MLZ User Meeting 2024

Dec 5, 2024, 12:00 PM → Dec 6, 2024, 5:00 PM Europe/Berlin

Munich Marriott Hotel

 

 

We are delighted to invite you to the MLZ User Meeting 2024 again at the Munich Marriott Hotel on Dec 05th & 6th! 

As always, the first day will be dedicated to specialized workshops organized by our Science Groups. And we will have an excellent conference dinner in the evening at a typical Bavarian restaurant.

On the second day, the MLZ Directorate will update on the current situation at the MLZ. Furthermore, scientific plenary talks by Judith Houston (ESS) & Günther Dollinger (Universität der Bundeswehr München) and a poster session will make this day! 

N.B.: Remember to attend our Date Evaluation Group's SANS-workshop on Dec 4th! 

 

Thu, December 5

12:00 PM → 1:00 PM Lunch

1:00 PM → 2:30 PM Material Science: MS I

1:00 PM Welcome by Science Group

1:05 PM Utilizing in-situ characterization techniques to probe the heat treatment response and micromechanical performance of LPBF processed and heat-treated Ti-6Al-4V

Ti-6Al-4V is the workhorse among all titanium alloys that are processed by solidification-based AM technologies. Its popularity resides from its interesting combination of quasi-static and dynamic mechanical properties, and its relatively low density, making it a candidate material for lightweight applications.
The structural performance of L-PBF processed Ti-6Al-4V parts, however, is heavily affected by the formation of a martensitic phase during rapid cooling, its partial decomposition during sequential heating and cooling cycles and a macroscopic internal stress distribution within L-PBF processed Ti-6Al-4V parts.
Martensite decomposition and stress relaxation behaviour in L-PBF processed Ti-6Al-4V is investigated using in-situ dilatomettry, allowing to inductively heat a sample while being irradiated by synchrotron X-rays, enabling to simultaneously measure the thermal expansion, phase fraction and internal stress evolution of an LPBF processed Ti-6Al-4V during heating and cooling.
The micromechanical behaviour of as-built and heat-treated two-phase Ti-6Al-4V samples is compared, both in the elastic and plastic regime, based on X-ray synchrotron diffraction spectra recorded during uniaxial tensile loading. The elastic stiffness and plasticity variations in the different hexagonal α and α’ phase directions is discussed and compared with numerically predicted critical resolved shear stress values.
The plastic deformation behaviour, strain localization and fracture onset of bilamellar Ti-6Al-4V, is discussed based on strain fields, obtained by 2D digital image correlation, recorded during uniaxial tensile loading inside a scanning electron microscope.
Generally, recommendations are given on how to heat treat LPBF processed Ti-6Al-4V alloys in order to enhance its quasi-static mechanical performance.

Speaker: Kim Vanmeensel (KU Leuven)

1:40 PM Influence of hydrogen on the γ-matrix lattice parameters of a Ni-based superalloy - a diffraction study

Hydrogen will play a significant role as an energy source and carrier. However, many material-related issues are yet to be clarified to successfully enable a hydrogen-ready energy infrastructure. In particular, hydrogen embrittlement of high-performance alloys is a well-known issue, which is still not entirely understood. Within this talk, the hydrogen embrittlement behaviour of the newly developed Ni-based superalloy VDM® Alloy 780 is discussed. An emphasis is set to understand the impact of hydrogen at the atomiclevel of the alloy. Therefore, specimens were charged electrochemically with hydrogen and subsequently characterized by synchrotron X-ray diffraction (XRD). The incorporation of hydrogen at interstitial sites of the crystal lattice leads to a slight increase of the lattice parameters as compared to hydrogen-free analogues. In-situ XRD measurements show converging lattice parameters of the charged and hydrogen-free samples at elevated temperatures. This indicates a reversibility of the hydrogen uptake by diffusion and subsequent effusion. Hot gas extraction measurements to quantify hydrogen concentrations within the alloys complement the diffraction data. Temperature-dependent hydrogen quantification suggests increasing diffusion rates of hydrogen with rising temperature, corroborating the findings of the XRD investigation. Additionally, tensile tests were conducted to quantify the influence of hydrogen on the alloy during deformation.

Speaker: Dr Alexander Mutschke

2:05 PM Macroscopic and microscopic residual stresses in nickel-aluminum bronze matrix composite surface deposits manufactured via laser melt injection

Nickel-aluminum bronze (CuBz) alloys are widely used due to their excellent mechanical properties and corrosion resistance. To enhance their use in high-value applications and lower the part replacement costs, improving their surface wear resistance is essential. Metal matrix composite (MMC) coatings have shown promise in this regard. One approach involves laser melting injection (LMI) of spherical fused tungsten carbide (sFTC), containing WC and W2C, onto CuBz substrates, reducing wear by up to 80%. However, residual stresses develop in MMC coatings, causing geometric distortion, reduced fatigue strength, and shorter service life.
This study uses neutron diffraction to analyze residual stress profiles in sFTC/CuAl10Ni5Fe4 coatings produced via LMI. A thermo-mechanical finite element model predicts temperature and stress patterns in the re-melted CuAl10Ni5Fe4 bronze. The effects of single/multiple laser tracks and pre-heating on residual stresses were explored. Additionally, detailed microscopic thermal misfit residual stresses were calculated. The results provide insights for optimizing the manufacturing process, reducing residual stresses, and improving MMC coating performance and longevity.

Speaker: Erik Walz (FRM II / STRESS-SPEC)

1:00 PM → 2:30 PM Neutron Methods: NM I

1:00 PM Welcome by Science Group

1:05 PM Parametric evaluation of boron based neutron imaging screens for improved detection efficiency and light output

Neutron imaging with cold and thermal neutrons typically use scintillator screens that use lithium-6 as a neutron converter. Compared to lithium-6, boron-10 offers nearly four time higher neutron absorption cross-section and larger daughter products that deposit their energy locally, offering the potential for higher neutron capture efficiency and spatial resolution. Screens were fabricated with varying neutron converter, mix ratio, phosphor type and particle size, and each screen had varying thickness. A set of over 200 samples was evaluated at ANTARES that represented thousands of parameter variations of screens. This series of measurements required changing samples between measurements over 600 times, which was enabled by the efficient facility and imaging system design at ANTARES and mature user program to facilitate access. The measurements led directly to two papers and development of improved screens continues. Boron-10 based screens exhibit higher neutron capture efficiency compared to lithium-6 based screens typically used today, offering improved image quality and/or reduced exposure times for the neutron imaging community.

Speaker: Aaron Craft (Idaho National Laboratory)

1:40 PM LumaCam: Event-Mode Neutron Detectors based on Scinillator Screens

LumaCam detectors have a structure resembling many established scintillator-based imaging detectors. The key difference is the imaging chip being fast enough to identify the individual scintillaton photons produced by a neutron interaction in the scintillator screen. This information can be used to provide enhanced spatial and temporal resolution, as well as noise suppression and particle discrimination capabilities. These advantages have led to a rapid growth in the usage of LumaCam detectors in the recent years, especially for time-of-flight imaging applications. We will explain the working principles of LumaCam detectors and illustrate the capabilities with results from many different applications such as fast and epithermal neutron resonance imaging, bragg-edge imaging, diffraction, and imaging at low flux sources.

Speaker: Alexander Wolfertz (TUM FRM2)

2:05 PM Neutron Event Simulation for AI-Based Data Processing

Recent developments of scintillator-based event-driven detectors have opened up the possibility of utilizing AI to identify single neutron events from sparse data readout. A crucial aspect for AI-based event detection is to provide training datasets that can be utilized to accurately train a neural network. Such training datasets require a “ground-truth” to avoid errors in the event identification process. To accommodate this, we present work on a Python-based simulation of neutron events to support AI-driven analysis of event data with a focus on position reconstruction of the events. The training-data simulation is based on observed distributions of photon characteristics utilizing event-mode neutron imaging, enabling the generation of large quantities of synthetic data. The objective of this project is to lay the groundwork for AI-based neutron event-mode imaging at the MLZ.

Speaker: Camille Gillespie (FRM-II)

1:00 PM → 2:30 PM Nuclear, Particle, and Astrophysics: NPA I

1:00 PM Welcome by Science Group

1:05 PM Status of the UCN source at FRM II

At the FRM II a UCN source with a solid deuterium converter and solid hydrogen premoderator, placed in a distance of ∼ 60 cm from the central fuel element inside the horizontal, through-going beam tube SR6, is currently under construction. It is supposed to generate UCN densities of 1000 - 10000 UCN per cubic centimeter in up to four connected experiments. This talk will give an overview of the current status of the project and an outlook to further developments and installations.

Speaker: Dr Andreas Frei (FRM II - TUM)

1:40 PM Towards first neutrons for neutron beta decay observations with PERC

The Proton Electron Radiation Channel (PERC) experiment will investigate the decay of the neutron by observing spectra of the emerging electrons and protons, and several correlations between neutron spin, and the electron, proton, and neutrino momenta. Its aim is in particular to improve on the parity violating beta asymmetry, and the Fierz term by an order of magnitude. PERC is under construction in the guide hall east of the FRM II and will use the intense cold beam of the MEPHISTO beam line.

In this talk, we will highlight the scientific impact on the current Cabibbo angle anomaly and the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, and the techniques to search for novel scalar and tensor interactions. We present the recent significant progress of the instrument and beamline, and discuss the route to the start of the science program next year.

Speaker: Irina Pradler (ATI - TU Wien)

2:05 PM Discussion

1:00 PM → 2:30 PM Quantum Phenomena: QP I

1:00 PM Welcome by Science Group

1:05 PM Insights Nuanced Magnetic Structure, Spin Superexchange, and Single-Ion Anisotropy in Perovskite-like CaCu$_3$Ti$_4$O$_{12}$ via Neutron Scattering Techniques

This comprehensive study delves into the complex magnetic properties and interactions of the perovskite-like compound CaCu$_3$Ti$_4$O$_{12}$, employing advanced neutron scattering techniques and resonant inelastic X-ray scattering (RIXS) to explore the underlying spin-orbital coupling and single-ion anisotropy. By synthesizing high-quality single crystals and utilizing a four-circle neutron diffractometer, we capture sufficient magnetic reflections to accurately determine the magnetic structure. In-depth investigations using a neutron three-axis spectrometer reveal the exchange interactions and anisotropic energies, elucidating the spin wave spectrum and highlighting the significant role of indirect exchange interactions mediated through Ti$^{4+}$. Additionally, the RIXS measurement uncovers the \textit{dd}-excitations, helping to establish the relationship along individual axes and confirming the anisotropic energies observed in the spin wave analysis. This research offers clear insights into both the collective spin-orbital coupling as modeled by the Kugel-Khomskii framework and the specific contributions of self-spin-orbit coupling concerned with single-ion anisotropy within CaCu$_3$Ti$_4$O$_{12}$. These findings contribute to a deeper understanding of magnetic interactions in systems with strong spin-orbital correlations and pave the way for future research into the delocalization of orbital excitation.

Speaker: Yung Hsiang Tung (Forschungszentrum Juelich JCNS-4)

1:40 PM Understanding the magnon dynamics in LuFeO3 for magnonics applications

Magnonics is a multidisciplinary field of research focusing on the study and application of magnons in information processing and technology [1]. Magnons can carry the spin information through thermally generated spin-wave spin currents over the large distances [2]. Insulating antiferromagnets (AFMs) are promising for next-generation high-density and high-speed spintronic applications due to their negligible stray field and ultrafast spin dynamics [3]. Especially, non-collinear AFMs with high magnon velocities corresponding to terahertz frequencies are greatly appreciated [1,4]. In view of the technological prospects LuFeO3 has attracted the attention[4]. We report here the magnon dynamics based on the inelastic neutron scattering studies performed on the single crystal of LuFeO3. The measured magnon dispersion along the (011) matches well with the simulated results obtained using the Holstein-Primakoff theory for the present antiferromagnets. Our analysis including the simulated and experimental results revealed that magnon propagates into such material with supersonic velocities of more than 20kms–1. This source of short wavelength magnon carriers opens the new prospects for terahertz antiferromagnetic magnonics and logic devices at terahertz frequencies.

[1] J. R. Hortensius, et al., Nat. Phys. 17, 1001 (2021).
[2] K. Uchida, et al., Nat. Mater. 2856, 10.1038 (2010)
[3] W. Lin, et al., Nat. Phys. 18, 800 (2022)
[4] J. Xu, et al., Phys. Rev. Lett 129, 117202 (2022)

Speaker: Dr Dnyaneshwar Raghunath Bhosale (Forschungszentrum Jülich, Lichtenbergstr. 1, 85747 Garching, Germany)

2:05 PM Phononic signature of spin-state crossovers in LaCOO$_3$

LaCoO$_3$ has been the subject of an intense investigation due to its intriguing transformation from a nonmagnetic insulator at low temperatures to a paramagnetic semiconductor, followed by an insulator-to-metal crossover. The nature of these transitions is the topic of long-standing and ongoing discussions. Generally, these crossovers are associated with the population of Cobalt low-spin (S = 0), medium-spin (S=1) and high-spin state (S = 2). An originally proposed order of low- and high-spin states should be visible via a concomitant structural distortion of LaCoO$_3$.
We have studied the lattice dynamical behavior of LaCoO3 with inelastic neutron and x-ray scattering over a large temperature range T = 2 K – 650 K combined with ab-initio lattice dynamical calculations based on density-functional-perturbation theory (DFPT). Our results reveal a pronounced anomalous softening of a low-lying phonon mode at $q_{pseudo-cubic}$ = (½,½,½) present over the range of the two crossover temperatures. The temperature range of the anomalous softening coincides with that in which magnetic fluctuations are observed in polarized neutron scattering. Thus, our results demonstrate a coupling of the magnetic to the lattice degrees of freedom and indicate the presence of dynamic spin-state order in LaCoO$_3$.

Speaker: Frank Weber (Karlsruhe Institute of Technology)

1:00 PM → 2:30 PM Soft Matter: SM I

1:00 PM Welcome by Science Group

1:05 PM Soft spheres at the interface probed by neutron reflectometry and interfacial rheology

Microgels - crosslinked polymer networks swollen in a good solvent - have been used to investigate the effect of compressibility on crystal and glass formation, and on its relation with the flow proprieties of the suspensions [1]. Their compressibility strongly affects microgels at interfaces [1, 2]. Here, poly(N-isopropylacryamide) (pNIPAM)-based microgels are confined at the oil- and air-water interface and used to investigate the flow properties of soft spheres in two dimensions [3]. We use neutron reflectometry to determine the particle architecture in-situ under compression and their response to external stimuli in the water phase [4,5]. Using interfacial rheology, two different flow-regimes are identified at different microgel concentrations, leading to two different master flow-curves. Both the storage modulus and the apparent yielding stress of the monolayer show a non-monotonic variation with concentration. Furthermore, the monolayer never reaches a jammed state. Computer simulations, based on a soft shoulder plus Hertzian model, confirm the non-monotonicity of the yield stress and the existence of different flow regimes.

[1] A. Scotti, et al. Chem. Rev. 122: 11675 (2022).
[2] A. V. Petrunin, et al. PCCP 25: 2810 (2023).
[3] M. M. Schmidt, et al. PRL 131: 258202 (2023).
[4] S. Bochenek et al. Nat. Comm. 13: 3744 (2022).
[5] Y. Gerelli et al. Soft Matter 20: 3653 (2024).

Speaker: Andrea Scotti (Division of Physical Chemistry - Lund University)

1:40 PM Influence of the architecture on the micellar structures from thermo- and pH-responsive triblock terpolymers

Self-assembled thermoresponsive hydrogels are attractive candidates for 3D bioprinting and tissue engineering. Here, we present a novel dual-stimuli system that features PDMAEMA, a weak cationic polyelectrolyte with pKa ~7.5 that is thermoresponsive when uncharged. It is combined in a triblock terpolymer with a hydrophobic polymethyl methacrylate block (PMMA, B) and a poly(N-(2-methacryloyloxyethyl) pyrrolidone) block (PNMEP, C), a hitherto uninvestigated polymer with a pKa of 5.2. The present study addresses the effect of the sequence of the two responsive blocks, namely BAC and BCA, on the temperature and pH-dependent micellar structures in dilute aqueous solution. Using dynamic light scattering and synchrotron small-angle X-ray scattering, we found that the micellar sizes and aggregation behaviour depend strongly on pH, temperature and the block sequence: At pH 6, both architectures show only little size change with increasing temperature. In contrast, at pH 8 and 25 °C, the hydrodynamic radius of the micelles formed by the BCA triblock terpolymer (24.5 nm) is larger than the one of the BAC (18.2 nm). Moreover, an increase in temperature results in the presence of large clusters of BCA micelles at 32 °C and above, while BAC does not exhibit any shape and size change up to 43 °C. Hence, the micellar structures depend strongly on the pH-value and temperature, and the same can be expected for the corresponding micellar hydrogels.

Speaker: Feifei Zheng (TUM)

2:05 PM Hybrid PNIPAM-based Hydrogels for Scalable H2 Evolution

Platinum (Pt) loaded carbon nitride (CN) is a promising photocatalyst under visible light for green hydrogen (H2) production. We aim to develop this system in a thin polymer film to make it industrially scalable.The Poly(N-isopropylacrylamide) (PNIPAM) hydrogel is used as a host matrix and water storage medium to facilitate homogeneous dispersion of the catalytic centers. The hybrid film's vertical distribution and inner microstructure are studied under in situ conditions with time-of-flight neutron reflectometry (ToF NR) and grazing incidence small angle neutron scattering (GISANS). The resulting H2 produced is measured by gas chromatography.

Speaker: Morgan Le Dû

1:00 PM → 2:30 PM Structure Research: SR I

1:00 PM Welcome by Science Group

1:05 PM Combined neutron- / X-ray crystal diffraction reveals switches for Fe(II) / Fe(III) binding in the cyanobacterial iron binding protein FutA that are resolved by XFEL X-ray induced photoreduction

Marine cyanobacteria are main contributors to carbon and nitrogen fixation, yet they are limited by iron availability. The most abundant and smallest photosynthetic organism on Earth is the cyanobacterium Prochlorococcus that can thrive in low nutrient waters. Interestingly, in contrast to most cyanobacteria that possess two FutA proteins to bind Fe(II) and Fe(III), Prochlorococcus has a single FutA iron binding protein, but the mechanism that would allow this single FutA protein to bind two different iron charge states remained unknown. Here we used neutron and X-ray diffraction to characterise FutA iron binding in different oxidation states at room temperature. The neutron diffraction study characterised the oxidised Fe(III) iron binding state, while a home source X-ray diffraction dataset revealed a reduced Fe(II) iron binding state. We characterised X-ray induced photo-reduction of the iron centre by spectroscopy. To study the transition between states we optimised crystallisation for serial experiments and designed a novel X-ray pump probe experiment that used an attenuated XFEL pulse for photoreduction, followed by a productive pulse to record data. The experiments reveal an alternative positioning of the Arg203 side chain in the second coordination shell of iron to maintain an overall charge neutral binding site for Fe(II) and Fe(III) states. This molecular switch provides a plausible mechanism for iron binding promiscuity. PNAS 121 (2024): e2308478121.

Speaker: Ivo Tews (University of Southampton)

1:40 PM Enhancing structural refinement of macromolecules obtained from neutron crystallography

Hydrogen atoms represent a large fraction of the total atomic content of macromolecules. Macromolecular X-ray crystallography affords the localisation of only the most ordered hydrogen atoms at (sub-)atomic resolution (around 1.2 Å or higher). However, many hydrogen atoms of biochemical significance remain undetectable by this method. Differently, neutron diffraction methods enable the visualisation of most hydrogen atoms, typically in the form of deuterium (2H) atoms at much more common resolution values (better than 2.5 Å). Novel refinement protocols have been implemented in the macromolecular refinement software REFMAC5, one of the flagship packages of the CCP4 suite of programs. One new feature for neutron data analysis in REFMAC5 is refinement of the protium/deuterium (1H/2H) fraction. Stereochemical restraints, including accurate covalent bond distances between the hydrogen atom and parent atom nuclei suitable for neutron refinement, are now included in the CCP4 Monomer Library, the source of prior chemical information used by REFMAC5. The newly developed REFMAC5 algorithms were tested by performing the re-refinement of several entries available in the PDB and of one novel structure (FutA) using either (i) neutron data only or (ii) neutron data supplemented by external restraints to a reference X-ray crystallographic structure. Furthermore, the refinement process of urate oxidase (UOX) in complex to a C5(S)-peroxo derivative of 9-methyl uric acid (MUA) is discussed.

Speaker: Lucrezia Catapano (MRC LMB)

2:05 PM Inspired by users: big data tools at the Swiss-Norwegian Beamlines at ESRF

The Swiss-Norwegian beamlines at the European Synchrotron Radiation Facility have now been in user operation for almost three decades. Over the last decade, the scientific activities on the beamlines have become more and more focused on solving problems in materials science and crystal chemistry, that also implies an advent of new users with little experience in synchrotron experimentation. Here we present an overview of the operational characteristics of the beamline software and the data tools developed for BM01 and BM31. The combination of large area detector Pilatus2M and flexible goniometer provides a very versatile diffraction platform for many types of X-ray diffraction and scattering experiments: powder diffraction, diffuse scattering, high-pressure experiments, surface diffraction and others.
The flexibility of the setup together with a large number of the experimental protocols requires a dedicated software for data acquisition and processing that has to be easy-to-use for beamline newcomers and, at the same time, must have a lot of advanced options for experts. An overview will be given to the SNBL data collection and processing pipeline: Pylatus (control software of the diffractometer), SNBL ToolBox (a set of tool for data reduction), Bubble (powder integration), Medved (data viewer) and a few other tools.

Speaker: Vadim Diadkin (SNBL@ESRF)

1:00 PM → 2:30 PM Positrons: e+ I

1:00 PM Welcome by Science Group

1:05 PM Open volume defects studies at NEPOMUC: highlights and future perspectives

I will review the main works done in the last years by my research group in collaboration with the researchers of NEPOMUC. These works include studies on vacancy like defects in silicon based materials, oxides, materials for hydrogen storage and soft matter.
At the light of the obtained results I will discuss the experimental requirements for a new class of measurements in material science at NEPOMUC.

Speaker: Prof. Roberto Brusa (University of Trento- Department of physics)

1:40 PM Investigation of free o-Ps decay at near zero implantation energy at the SLOPE facility

Depth resolved positron annihilation Doppler-broadening spectroscopy (DBS) at
the top-most atomic layer of solid materials is a fundamental but largely
unexplored field of research. This is because it requires monoenergetic
positron beams with energies in the order of only a few of eV.
SLOPE (Setup for LOw-energy Positron Experiments) is specially designed for
a low energy beam, enabling measurements down to implantation energies of
around 1 eV.
Previous depth resolved DBS measurements at SLOPE revealed a significant increase
in three gamma events at implantation energies below around 10 eV. This effect
is related to the Ore gap, which is the energy between the threshold of
Ps formation and the ionization energy of the target material.
We will present experimental results of this effect which showcase the
state-of-the-art capabilities of SLOPE.

Speaker: Maximilian Suhr (Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München)

2:05 PM Investigation of In-Flight Annihilation of Positrons using Coincidence Doppler Broadening Spectroscopy

Doppler Broadening Spectroscopy (DBS) of the positron electron annihilation line allows the analysis of defects inside materials. DBS uses the fact that during the annihilation momentum has to be conserved and is therefore transferred to the annihilation gammas. As a sufficient approximation the positron is assumed to be thermalized in the solid when it annihilates with an electron. In that case, the majority of the transferred momentum originates from the electrons.
However, when implanting high-energy positrons a small fraction of positrons will annihilate with electrons before thermalizing. This process of in-flight annihilation can be differentiated from annihilation of thermalized positrons by Coincidence DBS (CDBS). We used the CDB Spectrometer at the NEutron induced POsitron source MUniCh (NEPOMUC) in order get a deeper understanding of in-flight annihilation in several
materials of different densities and core annihilation probabilities. As positron source we utilized a 22Na source to supply high energy positrons. This not only gives insight into the thermalization process of the positron but also further expands the capabilities of the CDB Spectrometer.

Speaker: Leon Chryssos

2:30 PM → 3:00 PM Coffee break

3:00 PM → 4:40 PM Material Science: MS II

3:00 PM Investigating the ageing of multi-layer 5 Ah pouch cells with NCA cathodes and silicon anodes

The demand for Li-ion batteries continues to grow each year, whether for industrial applications or electric vehicles, making the enhancement of battery performance a key focus of research. One approach to achieving higher capacities is transitioning to materials with superior properties. Silicon has attracted significant attention as an anode material due to its high specific capacity of 3579 mAh/g, which surpasses that of conventional graphite. However, pure silicon experiences significant volume expansion during lithiation, causing mechanical stress that can lead to battery failure.
In this study, the lithiation mechanism and aging behavior of silicon anodes and LiNi$_{0.8}$Co$_{0.15}$Al$_{0.05}$O$_2$ (NCA) cathodes were examined in multi-layer 5 Ah pouch cells using neutron diffraction and promt gamma activation analysis (PGAA). The batteries were manufactured on a research production line at the iwb to closely replicate the conditions of commercial cells. Fresh cells, following formation and stabilization, were compared to aged cells at a 60% state of health.
As the cells age, capacity decreases, which is reflected in the evolution of NCA's cell parameters. The c- and a-parameters of the aged cells show a smaller range of movement compared to the fresh cells. Additionally, the peak positions of NCA shift during the relaxation phase after charging, indicating changes in the NCA structure because of Li loss. With the PGAA measuremetns, the loss of Li could be identified on both electrode and confirm the results from electrochemical and diffraction analyis.

Speaker: Thien An Pham

3:25 PM In-situ interface film forming on the high-voltage LiCoO2 cathode by a tiny amount of nanoporous polymer additives

LiCoO2 (LCO) has been proven for extensive commercial applications owing to its high specific capacity and stability. Therefore, there has been considerable interest in further enhancing its specific capacity by increasing the charging voltage. However, single-crystal LCO suffers from a significant capacity degradation when charged to 4.5 V due to the irreversible phase transition and unstable structure. Herein, an ultra-small amount (0.5%wt in the electrode) of multi-functional PIM-1 (a polymer with intrinsic microporosity) additive is utilized to prepare a kind of binder-free electrode. PIM-1 can modulate the solvation structure of LiPF6 due to its unique structure, which helps to form a stable, robust and inorganic-rich CEI film on the surface of LCO at a high voltage of 4.5 V. This reduces the irreversible phase transition of LCO, thereby enhancing cyclic stability and improving rate performance, providing new perspectives for electrodes fabrication and improving high-energy-density cathodes.

Speaker: Ruoxuan Qi (Technical University of Munich)

3:50 PM Targeted residual stress in electrical steel – Towards novel electric drives

Transportation, particularly motorized private transport, contributes significantly to fossil fuel con-sumption. Here, transitioning to battery electric vehicles (BEVs) is an option to reduce the con-sumption of fossil fuels. Electric drives used in BEVs require the careful guidance of the magnetic flux in the rotor. The rotor comprises a stack of non-oriented electrical steel sheets. Conventional-ly, material is removed from the sheets to create flux barriers. These removed areas reduce the mechanical strength and, hence, the achievable rotational speed of the drive, which affects its power density and efficiency. We showed that residual stress introduced by embossing, a local forming process, locally reduces the magnetic permeability. The locally reduced permeability dis-places the magnetic flux from these regions and concentrates it in other areas. Neutron grating interferometry, an advanced neutron imaging technique, is uniquely capable of mapping the magnetic flux displacement with high spatial resolution in the bulk of electrical steel.
In our contribution, we will present how nGI allowed us to verify the magnetic flux guidance by mapping the dependence of magnetic domain size and orientation on material parameters and applied magnetic field. Further, we will show our collaboration with mechanical and electrical en-gineering and an industry partner in a DFG transfer project to build more efficient electric drives using residual stress to guide the magnetic flux.

Speaker: Tobias Neuwirth

4:15 PM Perovskite Nanocrystal Nucleation Seeds for Improved Microstructure and Faster Crystallization in Organic-Inorganic Halide Perovskite Thin Films

Organic-inorganic halide perovskites have gained a huge interest in the scientific community owing to their favorable optoelectronic properties combined with their ease of production and abundance of raw materials. In many cases, polycrystalline thin films are fabricated for which thin film crystallinity and morphology are key factors affecting the perovskite properties. In this work, we present a novel approach for improving the thin film quality by employing external perovskite nanocrystals as seeds in slot-die coated formamidinium lead iodide thin films. Grazing incidence wide angle X-ray scattering (GIWAXS) and in-situ optical spectroscopy measurements show that the seed crystals improve the thin film texture by inducing a preferred crystallite orientation. Furthermore, we reveal a new crystallization pathway in seeded thin films with respect to unseeded ones via in-situ GIWAXS measurements.

Speaker: Mr Altantulga Buyan-Arivjikh (Technical University of Munich, TUM School of Natural Sciences, Department of Physics, Chair for Functional Materials)

3:00 PM → 4:40 PM Neutron Methods: NM II

3:00 PM MLZ-ELN as a new technical solution for an Electronic Laboratory Notebook

An existing ELN solution, the “Workbench”, ran as a prototype around the clock from September 2023 to June 2024. Due to the overall slow loading times with high data and user load, a new application has been under development since December 2023. While its frontend is heavily inspired by “Workbench”, the backend has been completely rewritten. It has the working title MLZ-ELN and has been running around the clock since July/2024 as a new ELN solution, again connected to Virtual Panda and an X-ray residual stress diffractometer.

Speaker: Josef Baudisch

3:25 PM MLZ open datacatalogue: What is the status?

Within the DAPHNE4NFDI consortium MLZ has been working on providing a FAIR data access option. The central part will be the MLZ datacatalogue ( which should be available before the Usermeeting).

We will show how the data in the catalogue look like, how you can really access it and a give an outlook on the coming data access options.

Speaker: Dr Bjoern Pedersen (Forschungs-Neutronenquelle Heinz Maier-Leibnitz(FRM II), TU München)

3:50 PM McStas for Virtual Experiments on PUMA

To increase neutron flux on small samples, we are developing a nested mirror optic (NMO) array for the PUMA thermal triple-axis spectrometer. This device is intended to reduce the beam size to 5 mm x 5 mm while preserving 50% of the incoming neutrons, resulting in an 8-fold increase in the flux available for small samples. However, the complex neutron flight paths generated from novel optics creates a new challenge in analyzing beam characteristics, such as the shape and the resolution function. We have integrated the McStas neutron simulation package with the McStasScript Python API to create a user-friendly GUI for simulating the PUMA instrument, including the new NMO optics. This combined program enables virtual neutron scattering experiments on PUMA. For staff, it facilitates testing optics, particularly NMO arrays. For users, it allows experiment simulations to optimize instrument parameters and acquire resolution functions. For students, it serves as a platform for learning neutron scattering techniques, offering practice in alignment and measurements without needing physical access to the instrument. We will discuss the progress of the NMO setup for PUMA and the McStasScript-PUMA integration, including planned features and capabilities.

Speaker: Adrian Merritt (Karlsruher Institut für Technologie)

4:15 PM Novel method for studying hydrogen storage process in the nanometer length scale using count rate of neutrons scattered at a small angle and probabilistic structure generation

Small-angle neutron scattering is useful for probing nanometer-scale structures but inhomogeneous materials like ball-milled powders used for hydrogen storage often yield fairly featureless diffraction patterns that are difficult to interpret [1]. Despite this, such patterns can still reveal important information. To explore this, Aslan et al. conducted an in situ investigation, measuring neutron count rates during hydrogen absorption and desorption [1]. The measurements revealed an increase in count rate during absorption and a decrease during desorption, with a further increase when hydrogen was replaced with deuterium. However, no change occurred during deuterium desorption, making it hard to extract real-space details about involved processes from the measurement.

To address this, probabilistic simulations were used to generate structures and calculate small-angle diffraction patterns [2]. Since the experiment measured count rates instead of diffraction patterns, a new method was developed to calculate neutron count rates from calculated diffraction patterns, accounting for instrument details [2–4]. The calculated neutron counts achieved qualitative agreement with experimental data, offering key insights into the hydrogen storage process that could not be obtained from measurements alone.
[1] 10.3233/JNR-190116
[2] 10.3390/ijms25031547
[3] j.nima.2016.06.105
[4] 10.1107/S1600576717011463

Speaker: Arnab Majumdar (Helmholtz Zentrum hereon)

MLZ_talk_Arnab.pdf

3:00 PM → 4:40 PM Nuclear, Particle, and Astrophysics: NPA II - CLOSED SESSION

3:00 PM → 4:40 PM Quantum Phenomena: QP II

3:00 PM Neutron diffraction study on magnetostructurally coupled triangular lattice antiferromagnet Ba3TbRu2O9

Ba3MA2O9 compounds have gained significant attention due to various exotic magnetic ground states depending upon the various combinations of M and A atoms. For instance: Ba3NiSb2O9, Ba3CuSb2O9, and Ba3IrTi2O9 exhibit quantum spin-liquid behavior [1-3], while Ba3ZnIr2O9 [4] shows a quantum spin-orbital liquid state. However, the magnetic ground of these compounds with M = rare-earth and A = 4d transition-metals is not explored too much. In this work, we show the magnetization and neutron diffraction results on Ba3TbRu2O9. Rietveld refinement of the neutron diffraction data infers the Tb magnetic order at ~9.8 K (TN) where ferromagnetic Tb moment planes are coupled antiferromagnetically along the c-direction. An antiferromagnetic Ru dimer ordering is also evident below TN from the Rietveld refinement of the neutron diffraction data. Further, the Rietveld refined Tb moment is fitted with the power law, and the derived critical exponent parameter indicates the 3D Ising interactions in the systems. Interestingly, the structural parameters like lattice constant, unit-cell-volume, and bond lengths show an anomaly at TN, indicating a magnetostructural coupling in the compound. The present study underscores the importance of the title compound in spintronic devices.

[1] J.G. Cheng, et al. Phys. Rev. Lett. 107, 197204 (2011).
[2] H.D. Zhou et al. Phys. Rev. Lett. 106, 147204 (2011).
[3] T. Dey, Phys. Rev. B 86, 140405 (2012).
[4] A. Nag, et al., Phys. Rev. Lett. 116, 097205 (2016).

Speaker: Dr Deepak Garg (Jülich Centre for Neutron Science at MLZ Forschungszentrum Juelich 85748 Garching)

3:25 PM Non-trivial Spin Structures and Multiferroic Properties of the DMI-Compound $Ba_{2}CuGe_{2}O_{7}$

Antiferromagnetic $Ba_{2}CuGe_{2}O_{7}$, characterized by a quasi-2D structure with Dzyaloshinskii-Moriya interactions (DMI), is a material that exhibits spiral spin structures with potential non-trivial topology and combines them with a variety of unconventional magnetic phase transitions. $Ba_{2}CuGe_{2}O_{7}$ is an insulator characterized by a tetragonal, non-centrosymmetric space group ($P\bar{4}2_{1}m$). The main features of the magnetic structure are due to the Cu2+ ions in a square arrangement. Below the Néel temperature $T_{N}$ = 3.05K, the DMI term leads to a long-range incommensurate, almost AF cycloidal spin spiral in the ground state.
Recently, a new phase with a vortex-antivortex magnetic structure has been theoretically described and experimentally confirmed in a pocket in the phase diagram at around 2.4K and an external field along the crystalline c-axis of around 2.2T. A lack of evidence for a thermodynamic phase transition towards the paramagnet in high resolution specific heat measurements and a finite linewidth in energy and momentum of the incommensurate peaks in neutron scattering, as opposed to the cycloidal ground state, seem to mark the vortex phase as a slowly fluctuating structure at the verge of ordering. Polarization measurements and neutron experiments including E-field in order to investigate its interplay with an external magnetic field are already planned and will allow for further pinning down multiferroic properties of $Ba_{2}CuGe_{2}O_{7}$.

Speaker: Peter Wild

3:50 PM Magnetic ground state in the frustrated Yb2-xNdxTi2O7 pyrochlore series

Pyrochlore magnets (R₂M₂O₇), with rare-earth ions arranged on corner-linked tetrahedra, are key to understanding magnetic frustration. These systems display diverse magnetic behaviors, including spin ice and spin liquid. Recently, researchers are exploring exotic magnetism by chemically manipulating or diluting these spin systems. We present magnetization and neutron-scattering measurements on polycrystalline samples of the Yb2-xNdxTi2O7 series. We recently synthesized Yb2-xNdxTi2O7 using the standard solid-state reaction, and powder x-ray diffraction analysis confirms this series adopts the pyrochlore structure. Fits to the dc magnetic susceptibility data using a Curie-Weiss law reveal a ferromagnetic coupling between the magnetic moments. Our ac magnetic susceptibility measurements show a sharp peak below 0.5 K, indicating a long-range order magnetic transition. As the neodymium content decreases, the transition shifts to lower temperatures, and the peak broadens, suggesting changes in the ground magnetic state and spin-spin correlations. Our investigation on the ground magnetic state of this new series for the composition x = 1 is characterized through neutron diffraction experiments down to 50 mK, and the inelastic neutron scattering experiment further confirms the crystal-field level and the magnetic anisotropy of the magnetic ions.

Speaker: Jonathan Gustavo Acosta Ramón (Jülich Centre for Neutron Science JCNS at MLZ, Forschungszentrum Jülich)

4:15 PM Magnetic structure in the new two-dimensional van der Waals ferromagnet Fe3GaTe2

Two-dimensional van der Waals (2D-vdW) ferromagnets are at the forefront of current condensed matter physics and materials science research due to their fascinating magnetic properties and massive potential in technological applications, such as magnetic tunnel junctions or spin current transmission. Fe$_{3}$GaTe$_{2}$, having a hexagonal structure of space group P63/mmc, is a new 2D-vdW ferromagnet with an exceedingly strong easy c-axis magnetic anisotropy and a very high Curie temperature (T$_{c}$) at about 380 K. There are similarities between Fe$_{3}$GaTe$_{2}$ and Fe$_{x}$GeTe$_{2}$ (x = 3~5), such as structure and magnetism. What is more striking is that Fe$_{3}$GaTe$_{2}$ has the best of both worlds: higher TC than Fe$_{3}$GeTe$_{2}$ and more valuable magnetic anisotropy than Fe$_{5}$GeTe$_{2}$, which makes Fe$_{3}$GaTe$_{2}$ particularly promising for potential applications. So far, few researchers have discussed the causes of Fe$_{3}$GaTe$_{2}$'s high TC and perpendicular magnetic anisotropy. Here, we grow high-quality Fe$_{3}$GaTe$_{2}$ single crystals and analyze their magnetic structure and behavior using VSM, XRD, and single crystal neutron scattering. Our research contributes to the development of novel 2D-vdW magnetic materials and will help the research of spintronic materials in the future.

Speaker: Po-Chun Chang

3:00 PM → 4:40 PM Soft Matter: SM II

3:00 PM Scattering Studies on Model Microplastic Flocculation

Microplastics have become a pressing issue due to their accumulation in aquatic and terrestrial environments and their presence in the food chain. In this talk, I will present the studies undertaken to flocculate a model microplastic system, viz., polystyrene latex suspension. This system, comprised of ~140 nm polystyrene spheres (microplastic) dispersed in water, was flocculated using Nanofloc® (VTA Technologie GmbH, Austria). The polystyrene particles serve as analogs to the microbeads in commercial face washes/scrubs and Nanofloc® induces flocculation. The polystyrene particles are negatively charged, while Nanofloc® solution is positively charged. A series of polystyrene colloids was prepared, and their flocculation was investigated using scanning electron microscopy (SEM), light scattering, and small-angle neutron scattering (SANS). The flocculation is instantaneous upon the addition of Nanofloc®. SEM image of the suspension, which exhibited complete flocculation, shows that the Nanofloc® uniformly covers the polystyrene particles with an interconnected network of compact and denser flocs. SANS studies were carried out as a function of polystyrene and Nanofloc® concentration. The scattering data for the particles with Nanofloc® was fitted using the models for fractal aggregates. The results of the study will be presented with details on model fitting, diffusion process, and the kinetics of flocculation.

Speaker: Dr BRIJITTA JOSEPH BONIFACE (Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH)

3:25 PM Water whitening of waterborne polymer films: Effect of the morphology of polymer latex.

Waterborne latex films, obtained from the dispersion of latex particles are of particular interest due to the non-content of volatile organic compounds (VOC), often mandatory under environmental legislation. However, abrupt water penetration inside the films restricts their lifespan and deteriorates the shine of the coating. In order to prepare efficient and solvent-free coatings with the low glass-transition temperature (Tg < the drying temperature) but with higher mechanical strength, hydrophilic layers were integrated (Acrylic acid/ Poly(acrylamide)) around the hydrophobic cores (mixture of Methyl methacrylate and Butyl acrylate) in the latex film. In another morphology of polymer latex, particles with soft core and hard shell were synthesized with different core-to-shell ratios, using emulsion polymerization. The water whitening of polymer films derived from solution was studied by the use of UV–vis spectroscopy, in situ SANS, and ESEM. The combined study provides the formation of the FCC-like structure by the latex films, which become more organized by including the hydrophilic hairy layers. The formation of water domains in the latex films disrupts the ordering of the films without having the hydrophilic layers while remaining intact for hydrophilic hairy layer latex films, when exposed them to water. On the contrary, latex films with soft cores and hard shells showed excellent water resistance and did not alter their ordering while exposed to water for a long time.

Speaker: Debasish Saha (FZ Juelich)

3:50 PM Insight on the myoglobulin interaction with lipid bilayers within sponge phases using polarized neutron reflectometry

We have studied the heme-protein-lipid interaction with lipid bilayers. This is key for understanding the encapsulation of the iron binding heme-protein like myoglobin and phytoglobin, in lipid nanoparticles, LNPs. This type of heme-bound iron can be used to treat anaemia instead of iron in organic salts that is conventionally used. Encapsulation is needed to prevent unwanted proteolytic and redox reactions. We have used sponge phase LNPs with diglycerolmonooleate (DGMO), glycerolmonooleate (GMO) and Polysorbate 80 (P80) as well as LNPs where DGMO was partially replaced with dioleoylglycerophosphocholine (DOPC) to form well defined lipid bilayers mimicking the lipid interface inside the sponge phase. To enhance the contrast and reduce the need for additional solvent contrasts we used silicon substrates with a switchable magnetic contrast layer (MCL) during polarised neutron reflectometry (PNR) experiments [8]. These substrates consisted of 10 nm Fe layer capped with 100 nm SiO2 layer to protect the Fe layer against corrosion and gave excellent response to the spin state of the neutrons. The formed lipid bilayers had a very high coverage of about 90%, which allowed studies of the interaction of the protein with the lipid interface. The results show that myoglobin interacts so strongly with the lipid bilayer that it was mostly removed from the substrate. The presence of DOPC increased the stability of the bilayer so that remains intact with very low amounts of protein attached.

Speaker: Prof. Tommy Nylander (Physical Chemistry, Lund University, Sweden)

4:15 PM Deuteration Service for Users of the MLZ Neutron Scattering Instruments

In order to provide users of the neutron scattering instruments at the MLZ with the appropriate partially or fully deuterated materials the JCNS built up a deuteration service, primarily from our core competence areas of polymers and ethoxylation. Similar services exist at other neutron sources, such as the ILL, ISIS or ANSTO. However, we are the first dedicated deuteration laboratory for neutron users in Germany.
During the MLZ User Meeting we want to present our services and capabilities to the MLZ user community. We will also detail how people can access our services and present the plans to incorporate our service into future neutron proposal calls at the MLZ.
We offer the deuteration of various soft matter systems, including polymers, surfactants and a variety of small molecules. We are capable of conducting different methods of controlled polymerizations, such as anionic or RAFT polymerizations, to generate polymers with narrow polydispersities and precise molecular weights. In addition, we are equipped to work with deuterated ethylene oxide in order to synthesize PEO and perform ethoxylations. Our catalogue of small molecules includes various deuterated monomers, surfactants as well as deuterated phase transfer catalysts.

Speaker: Kuno Schwärzer

3:00 PM → 4:40 PM Structure Research: SR II

3:00 PM Diffraction Computed Tomography for Non-Destructive Analysis of Li-Ion Batteries

This contribution discusses the application of Diffraction Computed Tomography (DCT), including both X-ray and neutron probes, as a powerful method for non-destructive structural analysis in materials science. DCT uses a pencil-beam scanning technique to yield the reconstructed images of internal structure and chemical gradients of materials, extending the traditional imaging approaches. A notable application of DCT is in the study of commercial lithium-ion batteries, where it has been used to resolve inhomogeneities in lithium distribution and structural evolution during cycling. We apply DCT to various commercial battery types, specifically focusing on cylindrical cells with different diameters, featuring diverse chemistries such as NCA, NMC, and graphite anodes. By employing high-resolution DCT, we map lithiation distributions and investigate electrode degradation mechanisms, providing key insights in battery performance and aging. The efficiency of the method, state-of-the-art resolution capabilities, and technique’s extension to neutrons are discussed.

[1] V. Kochetov et al, Powder diffraction computed tomography: a combined synchrotron and neutron study, J Phys Condens Matter 33 (10), 2021.
[2] D. Petz et al, Lithium distribution and transfer in high-power 18650-type Li-ion cells at multiple length scales, Energy Storage Mater 41, 2021.

Speaker: Dr Vladislav Kochetov (FRMII TUM)

3:25 PM Silicon-Induced Structural Changes in Commercial Li-ion Battery Anodes

This study investigates the structural dynamics of silicon-containing graphite anodes in commercial lithium-ion batteries (LIBs) using systematic X-ray and neutron powder diffraction techniques. Silicon, increasingly used in state-of-the-art LIB anodes, due to its potential to enhance battery performance, shows significant volume expansion, and the amorphization of silicon during lithiation [1, 2]. Such issues complicate the direct detection of lithium redistribution within the anode using diffraction techniques. However, an indirect structural response of silicon lithiation was observed, by the delayed Li intercalation into the graphite structure. Additionally, the study focuses on the impact of aging of high-silicon-content anodes, showing the degradation of the cell electrodes and the role of silicon in this process. The findings contribute to a better understanding of the complex interplay between silicon content, structural stability, and lithium distribution in advanced LIBs.
[1] Moon, J., et al., Nature Communications, 12(1), 2021 (DOI: 10.1038/s41467-021-22662-7).
[2] Limthongkul, P., et al., Acta Materialia, 51(4), 2003 (DOI: 10.1016/S1359-6454(02)00514-1).

Speaker: Tobias Hölderle

3:50 PM Temperature-resolved Crystal Structure of Ethylene Carbonate

For more than three decades, lithium-ion batteries (LIB) have been widely used as power sources for portable electronics and are of interest for electric vehicles and network applications (large-scale electricity storage). While there have been significant changes from the initial design of the LIB, the main solvents constituting the liquid electrolyte, responsible for the charge transfer between the electrodes, remained mainly unchanged [1]. An important class of solvents used in liquid electrolytes are linear and cyclic carbonates, because of the combination of physical/chemical properties in a mixture with two or more solvents with a lithium salt and additives [1]. Ethylene carbonate (EC), with its high dielectric constant [1] and ability to provide the protective SEI layer, is present in almost all commercial batteries, mixed with other solvents due to its high melting point [2].
After the determination of the crystal structure of EC from single crystals [3], this contribution presents room temperature data obtained by Neutron Powder Diffraction at SPODI (FRM II), temperature-dependent Neutron Powder Diffraction data from ECHIDNA (ANSTO) and Total Scattering and temperature dependent Powder X-Ray Diffraction data measured at P02.1 (DESY), showing the structural evolution from 3 K up to its melting point.
[1] G. Eshetu et al., Phys. Chem. Chem. Phys. 15, 9145-9155 (2013)
[2] J.-M. Tarascon & M. Armand, Nature 414, 359-367 (2001)
[3] C.J. Brown, Acta Cryst. 7, 92-96, (1954)

Speaker: Lea Westphal (TUM/MLZ)

4:15 PM Operando investigation of the electrolyte uptake of the electrodes in 18650-type Li-ion batteries

During the operation of Li-ion batteries, Li-ions are exchanged between the cathode and the anode of the battery. During this exchange, the lithium gets extracted (deintercalated) from one electrode and inserted (intercalated) into the other electrode. During this mass transport the structure of the materials changes, which leads to and volume expansion/contraction of the electrode materials. As these volume changes of the materials are non-linear, the liquid electrolyte get soak into / pressed out of the liquid electrolyte [1].
In this contribution, the theoretical changes of the electrode material were related to the operando liquid electrolyte excess measured with neutron radiography visible inside the center pin of the cell. The results have shown the correlation between the electrolyte uptake of the electrodes and the non-linear volume changes of the electrode materials.

1. Ziesche, R.F., et al., 4D imaging of lithium-batteries using correlative neutron and X-ray tomography with a virtual unrolling technique. Nature Communications, 2020. 11(1): p. 777.

Speaker: Dominik Petz

3:00 PM → 4:40 PM Positrons: e+ II

3:00 PM Ab initio calculations of positron lifetimes and the comparison with lifetime measurements in photochromic rear-earth oxihydrides

Rare-earth oxihydrides show a reversible photochromic effect, whereas the details of the underlying mechanism are not yet fully understood. A major influence on properties such as band gap, electrical conductivity, or light absorption is achieved by modifying the chemical composition, i.e. the O$^{2-}$ and H$⁻$ content of the material. Recently published results of PALS measurements performed with the Pulsed Low-Energy Positron System (PLEPS) at the research reactor FRM II on magnetron sputtered Yttrium-based thin films report the occurrence of different positron defect lifetimes in the materials. Very often, such results are difficult to interpret because, especially in complex materials, different defect types may lead to similar positron lifetimes.
Therefore, ab initio calculations, based on ABINIT were performed for further interpretation. ABINIT is an open-source software suite that uses density functional theory (DFT) using a plane wave basis set and pseudopotentials. With an additional package, self-consistent field calculations can be performed to determine positron lifetimes based on two-component density functional theory (TCDFT) using the projector augmented-wave (PAW) method. For our calculations, we used the local density approximation (LDA) and the generalized gradient approximation (GGA). The calculations and our measured data show a high degree of agreement. Furthermore, the DFT results help us to interpret the results.

Speaker: Marcel Dickmann

3:25 PM Positrons in a magnetic dipole trap: injection, confinement, and cooling

Many instabilities common to magnetized ion-electron plasmas are expected to be absent or suppressed in electron-positron "pair" plasmas. APEX (A Positron Electron eXperiment) aim to create and confine a low-energy pair plasma by combining non-neutral plasmas of electrons and positrons in a purely magnetic trap [1]. A significant challenge associated with this task is the accumulation and injection of sufficiently many positrons to obtain plasma densities. A lossless E×B-drift technique was recently adapted to inject bunches of positrons into a supported dipole trap [2]. The positron bunches were produced using a buffer-gas trap at the AIST positron facility [3]. An array of 21 gamma-ray detectors [4] was utilized to monitor annihilation events and investigate positron transport, cooling, and loss mechanisms (including Ps-formation) in the inhomogeneous magnetic field. We aim to extend this work by injecting bunches of positrons from the NEPOMUC into a levitating dipole trap [5], with the ultimate goal of producing and studying a low-energy pair plasma.

[1] Stoneking, et al. (2020), J. Plasma Phys., 86, 155860601.
[2] Deller, et al., Phys. Rev. E. (2024) 110, L023201.
[3] Higaki, et al. (2020), Appl. Phys. Express 13 066003
[4] von der Linden, et al. (2023), J. Plasma Physics, 89, 905890511.
[5] Card, et al. IEEE Trans. Appl. Supercond. (accepted) doi: 10.1109/TASC.2024.3462796

Speaker: Adam Deller (IPP)

3:50 PM The Ophanim Detector: Data Flow Architecture and Power Supply of a spatially resolved Antihydrogen Detector

The AEgIS experiment at CERN aims to measure the acceleration of cold antimatter in earth's gravity field by determining the vertical displacement of the beam. An important part of the experimental setup is a detector, that can determine the position of the antimatter particles. For this purpose, the Ophanim detector - a CMOS sensor with 3.85 billion pixels - is developed.
In order to transport Ophanim's large amounts of data, a pipeline with high bandwidth is necessary.
This presentation outlines, how the MIPI CSI-2 Protocol and USB SuperSpeed can be used to accomplish a fast and reliable data transfer.
Additionally, a fast and precise power supply is required to power the detector inside of the vacuum chamber. The discussion will explore how this is achieved using analog electronics.

Speaker: Markus Muenster (Student)

4:15 PM Development of a spatially resolved Antihydrogen Detector based on CMOS image sensor technology

To measure the gravitation pull on Antimatter, the AEgIS collaboration at CERN aims to perform moiré deflectometry on a beam of cold Antihydrogen. For such a measurement to be sufficiently accurate, the resulting fringe pattern needs to be resolved with micrometric accuracy. Here we present the technology and design considerations behind the OPHANIM detector, a purpose built Antihydrogen detector tailored to the requirements of the AEgIS gravity measurement.

Speaker: Michael Berghold (NEPOMUC / FRM2)

4:40 PM → 5:10 PM Coffee break

5:10 PM → 6:00 PM Material Science: MS III

5:10 PM 3D Hydrogen mapping in oil-filled porous steel gears for self-lubrication

Fluid-based lubrication systems in gearboxes are ubiquitous in present-day mechanical engineering to reduce power losses during operation, increase service life and efficiently dissipating heat. By integrating the volume of lubricating oil required for contact lubrication into the pores of a sintered component where it can extrude under load, the lubrication and sealing system can be significantly simplified or even completely eliminated. Oil-impregnated sintered friction bearings are commercially available, but the load bearing capabilities of these systems are not sufficient for the contact surfaces of toothed gears. In a novel approach, materials for gear fabrication were designed, targeting a specific porosity to enable oil impregnation of gears. Such impregnated gears will yield an improvement in tribological properties compared to conventional dry or once-lubricated systems while retaining their original mechanical strength, thus enabling to optimize the design of future gearboxes. The process of filling such porous steel gears with oil is currently being investigated. To understand this process and investigate the homogeniety of the distribution of oil in the gear, neutron imaging measurements were performed. Due to the flat sample geometry, neutron computed laminography was applied to spatially map the oil distribution in 3D for both filled and tested gears. Revealing inhomogenieties from filling and low oil contents in the state after successful extrusion under load.

Speaker: Simon Sebold (MLZ)

5:35 PM Alkaline and enzymatic hydrolysis of poly-(ethylene terephthalate) plastics: kinetics and mechanistic insights obtained through Neutron Reflectometry

With more than 82 million tons produced worldwide every year, poly-(ethylene terephthalate), PET, is one of the largest source of plastic waste. Among the various remedies sought to reduce the amount of PET into the environment, enzymatic hydrolysis holds great promise for upscaling. However, one of the challenges to overcome is the rapid loss of catalytic activity leading to incomplete polymer hydrolysis.
Many studies have been conducted to shed light on this issue, although methods that can provide direct measurement of polymer hydrolysis are lacking, making it difficult to obtain information from which to deduce mechanistic details. With the aim to fill this gap, we have used time-resolved Neutron Reflectometry (NR) as a technique to follow the PET degradation and providing a direct assessment of the hydrolysis rate of the polymer, and obtaining at the same time structural information on the enzyme /polymer/water system. We have seen that the enzymatic hydrolysis follows the Michaelis-Menten rate law, whereas the alkaline degradation is a pseudo first order kinetics, as expected. At the concentrations used in the experiments, the areal density of enzymes at the polymer surface is very low, ruling out surface passivation or overcrowding as inhibition mechanisms.

Speaker: Gaetano Mangiapia

5:10 PM → 6:00 PM Neutron Methods: NM III

5:10 PM Multiple scattering in polarized neutron diffraction

Polarized neutron diffraction is proven to be a powerful tool for studies of magnetic structure and microscopic dynamics of matter. This is assured by the success of the XYZ-polarization analysis technique, which lays the basis for separation of coherent, incoherent, and magnetic contributions to the scattering cross section. Even though polarized diffraction can provide a more robust information about the sample, it is characterized by a reduced neutron count rate as compared to unpolarized measurements. As a result, scientists may prefer to use thicker samples in order to achieve sufficient statistics with the shortest possible measurement time. It is also often the case that even for moderate sample thickness multiple scattering (MS) cannot be avoided when strongly scattering samples are investigated. Additionally, a prior knowledge of significance of MS can be used to choose an optimal sample geometry. All in all, effect of MS is usually significant enough and must be considered when analyzing the diffraction data.

In our work, we review existing approaches in handling MS in polarized neutron diffraction and investigate the possibility of a data-driven extraction of the respective contribution. We use McStas simulations, in which multiple scattering can be precisely estimated, as a baseline for comparison. We plan to incorporate the most suitable approach into the data reduction software used for processing polarized diffraction data at the DNS instrument.

Speaker: Oleksandr Koshchii (JCNS at MLZ, Forschungszentrum Jülich GmbH)

5:35 PM HYMN – A novel unified toolbox for in-situ magnetic hyperthermia experiments using neutron scattering

One of the most promising cases of magnetic hyperthermia is using magnetic nanoparticles (MNPs) in cancer therapy. In this treatment, MNPs are immersed into tumours and, by heating with external magnetic fields, typically 100-900 kHz, destroy cancer cells. Since it is a clinical application, optimising field parameters and the heating power is crucial to maintain both safety and high efficiency. Safety dictates an upper limit of the applied magnetic field. Hence, for a successful application, the heating power needs to be improved by optimising the MNP structure. Moreover, recent studies have shown a massive increase in magnetic heating by the excitation of transversal spin modes in MNPs in the low GHz range. An ideal tool for characterising such MNPs is small angle neutron scattering (SANS), with the extended functionality provided by the MIEZE technique. Our ERUM-Pro HYMN project aims to develop a novel, unified experimental and computational toolbox for in-situ magnetic hyperthermia experiments under clinical conditions, utilising the SANS and MIEZE-SANS techniques combined with nanomagnetic simulations. This will be achieved by developing two custom-made setups for operation in the 100-450 kHz (up to 30 mT) and 0.5-4 GHz (up to 2 mT) range. We present the first SAXS and SANS results, where we used in-situ RF heating at 450 kHz to examine magnetite nanocubes with 12, 34 and 53 nm sizes. For these samples, we have found promising indications of dynamic structure formation.

Speaker: Michal Dembski-Villalta

5:10 PM → 6:00 PM Nuclear, Particle, and Astrophysics: NPA III - CLOSED SESSION

5:10 PM → 6:00 PM Quantum Phenomena: QP III

5:10 PM Requirements for hydrogen absorption experiments with RNR in Pd/Co/Pd

Pt/Co/Pt and Pd/Co/Pd heterostructures with perpendicular magnetic anisotropy (PMA) are traditionally used for magnetic recording. PMA can be tuned by e.g. thin film thickness, strain, ion bombardment or temperature. Recently, it has been shown that the absorption of hydrogen in the heavy metal modifies the interfacial spin-orbit coupling and hence reduces the PMA.[1-3] As a result, reversible and non-destructive toggling of the easy axis of magnetization between in-plane and out-of-plane orientation at room temperature was demonstrated in a Co/GdO$_x$ all-solid-state device for magnetic hydrogen sensing.[4]

Resonance enhanced polarized neutron reflectometry (RNR) is an effective tool for studying the hydrogen uptake quantitatively and with time resolution of less than seconds and the hydrogen impact on the magnetic properties in PMA systems.[5]

In this contribution we report on results of RNR experiments on hydrogen uptake in Pt/Co/Pt trilayers sandwiched by 25 nm Nb layers on MgO(001) substrates fabricated by molecular beam epitaxy measured at D17 at ILL and the requirements to measure the switching of the easy axis on hydrogen uptake in the trilayer systems Pt/Co/Pt and Pd/Co/Pd.

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[1] S. M. Valvidares, et al., Phys. Rev. B 81, 024415 (2010)
[2] K. Munbodh, et al., Phys. Rev. B 83 094432 (2011)
[3] G. Causer et al., ACS Appl. Mater. Interfaces 38 35420 (2019)
[4] J. Tan et al. Nature Materials 18 35 (2019)
[5] L. Guasco et al., Nature Comm. 13 1486 (2022)

Speaker: Dr Sabine Puetter (Jülich Centre for Neutron Science JCNS at MLZ, Forschungszentrum Jülich GmbH)

5:35 PM Understanding the mechanisms of hydrogen induced modifications in correlated oxides.

Correlated oxides are the ideal platform for hydrogen induced structural and electronic modifications, due to the presence of high amount of oxygen, a quite flexible crystal structure and the delicate balance between structural and electronic degrees of freedom. A striking example are the nickelates, for which hydrogen can induce metal to insulator transitions [1], superconductivity [2], and colossal lattice expansion [3]. The mechanisms of interaction between hydrogen and the oxide is often not fully understood, due to the difficult detection of hydrogen in thin films. Neutron reflectometry (NR), in combination with x-ray scattering and other complementary techniques, can be a powerful tool for non-destructive, in situ, non-local characterization of such systems. Here we report on the specific case of LaNiO$_{3}$ which exhibits an intermediate insulating state followed by re-entrant metallicity accompanied by colossal expansion during hydrogen exposure. Via in situ NR we measured time-dependent hydrogen and oxygen content in the layer during reaction with H$_{2}$. By combining the stoichiometry obtained from NR with the x-ray diffraction and absorption spectra at various stages of reaction we propose a full reaction mechanism to explain the electronic phase changes observed.

References
[1] J. Shi, Y. Zhou, S. Ramanathan, Nat. Commun. 2014, 5, 4860.
[2] Ding, X., Tam, C.C., Sui, X. et al. Nature 615, 50–55 (2023).
[3] Haowen Chen, et al. Nano Letters 2022 22 (22), 8983-8990

Speaker: Laura Guasco

5:10 PM → 6:00 PM Soft Matter: SM III

5:10 PM Water dynamics in conductive PEDOT:PSS/cellulose nanocomposite films

PEDOT:PSS is a water-dispersable and electrically conductive polymer blend that is increasingly applied in numerous fields such as batteries and super-capacitors. While many studies focus on performance optimization, degradation issues because of humid environments are rarely discussed: PEDOT:PSS absorbs significant amounts of water (~50 wt%), which leads to a pronounced swelling factor of up to 1.6.
The integration of PEDOT:PSS into a cellulose nanofibril (CNF) matrix enhances significantly the mechanical integrity and limits water absorption. Moreover, a complex nanocomposite morphology is generated, which changes in dependence on the ambient humidity: high humidity leads to de-wetting of PEDOT:PSS from CNF bundles. As a result, the conductivity decreases. Upon drying, this behavior is reversible, however only after a first drying/humidifying cycle, which we refer to an initial kinetically trapped film morphology.
By studying the water dynamics via QENS, we identified two water species inside the films: fast-moving bulk water and slow-moving hydration water. In dry conditions, bulk water is completely released from the films, while parts of the hydration water remain inside the films. The remaining hydration water fraction provides a certain mobility for the PEDOT:PSS chains and supports their wetting on the CNF bundles. In addition, the QENS measurements provide detailed information about the diffusive behavior and the hydrogen-bonding environment of water molecules.

Speaker: Dr Lucas Kreuzer (MLZ (FRM II, TUM))

5:35 PM Structure and dynamics of a quasi-binary liquid in 2 and 3 dimensions

We investigated a quasi-binary liquid of 3-methyl pyridine and heavy water at the critical composition at different temperatures close to the phase transition. When adding antagonistic salt sodium tetraphenylborate the ions form locally lamellar structures that enclose the binary fluid. Then the system becomes 2-dimensional. Looking at the critical fluctuations, the dimensionality is confirmed. The dynamics of the 3 and 2-dimensional system displays diffusion on large length scales (dynamic light scattering) and fluctuations of the boundaries between the domains on small length scales (neutron spin echo spectroscopy). From that we obtain a master curve following the theory of Kawasaki. On the one hand the critical exponent $z$ is obtained that can be rationalized by theoretical concepts. The overall prefactor $R$ of the master curve displays approx. 2 times faster diffusion for the 2-dimensional compared to the 3-dimensional system. This can be explained by much lower viscosities (also measured) of the 2-dimensional system. This is theoretically explained by the lubrication effect.

Looking at the high-$Q$ scattering, we determined the critical correlation-function exponent $\eta$ that is extraordinarily large for the 2-dimensional system. It seems that the composition fluctuations in the 2 dimensions and the 3rd dimension are orientationally averaged.

A short excursion will also look on an aerogel as porous material that interferes with the binary fluid.

Speaker: Henrich Frielinghaus (JCNS)

5:10 PM → 6:00 PM Structure Research: SR III

5:10 PM Orthorhombic Symmetry and Anisotropic Properties of Rutile TiO2

The symmetry of the material is an important factor determining its properties. In this work, we demonstrate [1] both experimentally and by numerical simulations that the actual symmetry of the rutile phase of TiO2 is CaCl2-type [2] orthorhombic, described with space group Pnnm, in contrast to what it is commonly believed that rutile TiO2 has a tetragonal symmetry [2-4], described with space group P42/mnm. We present very precise first-principles calculations for the determination of the structural properties of rutile TiO2 and highlight the relevance of using the revised regularized SCAN meta-GGA density functional for the interpretation and analysis of neutron and synchrotron radiation diffraction measurements. We showed that symmetry lowering is present in both lattice constants and atomic positions. The lowering of the symmetry has a small but not negligible influence on the elastic, vibrational, and optical properties of rutile TiO2. Results are discussed in the context of analogous lower symmetry structure description in other rutile-type compounds: β-PbO2 [5], β-MnO2 [6] and MnF2 [6].
References:
[1] N. Gonzalez Szwacki, et al.; J. Phys. Chem. C 127 (2023) 19240
[2] W. H. Baur; Crystallogr. Rev. 13 (2007) 65
[3] D. T. Cromer and K. Herrington; J. Am. Chem. Soc. 77 (1955) 4708
[4] J. K. Burdett, et al.; J. Am. Chem. Soc. 109 (1987) 3639
[5] P. Fabrykiewicz, et al.; Phys. Rev. B 103 (2021) 064109
[6] P. Fabrykiewicz, et al.; Acta Cryst. A 75 (2019) 889

Speaker: Piotr Fabrykiewicz (Institute of Crystallography, RWTH Aachen University, Germany and Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching, Germany)

5:35 PM Wrap up

5:10 PM → 6:00 PM Positrons: e+ III

5:10 PM Vacancy defects in CsPbBr$_3$

The metal halide perovskites (MHPs) are attracting intense research interest due to their excellent optoelectronic properties. The all-inorganic member CsPbBr$_3$ is of particular interest for gamma-ray detector applications and LEDs. Further, single crystals can be grown via a solution route or by a melt process, and thin films can be solution processed or produced by vapour deposition.
Here we report the results of two-component density functional theory (TC-DFT) calculations for CsPbBr$_3$ and the results from variable-energy positron annihilation lifetime spectroscopy measurements on a range of single crystal CsPbBr3 samples as well as vapour processed thin samples. The TC-DFT calculations return positron lifetime values approximately similar to those previously reported for the model MHP MAPbI$_3$. Evidence for the detection of both B-site and A-site vacancy defects is presented.

Speaker: David Keeble (University of Dundee)

5:35 PM Pulsed Positron Beams for Materials Sciences at NEPOMUC

Pulsed low-energy positron beams of variable energy are powerful
tools for defect profiling in materials with positron annihilation lifetime spectroscopy (PALS). The UniBwM operates two pulsed positron beams at NEPOMUC: The Pulsed Low-Energy Positron System (PLEPS) for depth-resolved (1D-)defect profiling and the Scanning Positron Microscope (SPM), which in addition offers lateral micrometer resolution, thus enabling for the first time to measure 3D-defect distributions.
At first, we describe how PLEPS and SPM work in their present versions. To illustrate the unique features and possibilities our pulsed beams offer we show selected examples of PLEPS and SPM applications to condensed matter problems. Finally, we will give an outlook of the future developments of PLEPS and SPM at NEPOMUC.

Speaker: Werner Egger (Universität der Bundeswehr München)

8:00 PM → 11:00 PM Dinner

Fri, December 6

9:00 AM → 9:45 AM Plenary: Talk by Judith Houston (ESS)

9:00 AM Squishy stuff Probed by Small-Angle Scattering and Rheology

The aim of our research is to achieve a fundamental understanding of compressible soft materials, both static and under flow, and use this knowledge to further develop bio-relevant colloids. An object's bulk modulus K quantifies its resistance to an isotropic compression. For deformable colloids, K must be known to predict their response to crowding. Here, we will first present a new approach to exert osmotic stress on soft objects using partially-deuterated, high molecular weight, polyethylene glycol [1]. In this study, microgels were used as a model system for soft compressible spheres and their bulk modulus was determined by means of small-angle neutron scattering with contrast matching. We then extended this study to probe the effect of softness under shear using (i) a 1,2-shear cell to study the shear banding phenomenon in suspensions of microgels [2], and (ii) then analysis unprecedented shear thinning behavior at extremely high shears using a capillary rheometer. Both shear cell environments are currently being developed at ESS together with collaborators from MaxIV.

[1] J. E. Houston, L. Fruhner, A. de la Cotte, J. Rojo González, A. Petrunin, U. Gasser, R. Schweins, J. Allgaier, W. Richtering, A. Fernandez-Nieves, A. Scotti. Resolving the different bulk moduli within individual soft nanogels using small-angle neutron scattering. Science Advances 8: eabn6129 (2022).
[2] G. Bassu, J. E. Houston, M. A. Lara-Pẽna, H. Kriegs, M. P. Lettinga, L. Porcar, A. Scotti, M. Laurati, Link between permanent shear-banding and local concentration fluctuations in suspensions of compressible microgels, under review (2024).

Speaker: Judith Houston (European Spallation Source)

9:45 AM → 10:00 AM Plenary: Laudatio and award ceremony "MLZ Prize for Instrumentation and Scientific Use"

10:00 AM → 10:45 AM Plenary: Talk by Günther Dollinger (UniBW)

10:00 AM Materials Research Utilizing Pulsed Positron Beams at FRM II

Atomistic defects and voids often determine the mechanical, electrical or optical properties of materials. Positron lifetime spectroscopy offers the unique potential to analyze and characterize vacancy type atomic defects, defect clusters and nanoholes in nearly any kind of material. Our institute has developed instruments that use pulsed, low energy positron beams to obtain best resolution and sensitivity for the analyzes of these vacancy type defects. Our positron instruments profit from the high intense positron source NEPOMUC at FRM II that offers the most intense low energy positron beam world-wide.
In the talk I will review the state of the art of our two instruments: the Pulsed Low Energy Positron Spectrometer (PLEPS) and the Scanning Positron Microscope (SPM). I will demonstrate the actual performance on the basis of characterization of different kind of materials including tungsten materials for fusion first wall materials, nano-membranes and metal organic frameworks. I will also show actual research questions on nitrogen-vacancy centers in diamond as discussed as a quantum material that wait for further insitu analysis for charging and decharging by insitu light illumination at PLEPS.
The development of the instruments is by far not yet finished: The SPM is still waiting for the first positrons on the positron research platform of NEPOMUC and its transfer to its new position in the east hall of FRM II. In addition, the quality of the positron beams and the instruments can still be improved enhancing quality of lifetime spectra, improving insitu manipulation (light, electrical fields) of samples, combining positron lifetime spectroscopy with momentum analysis of the emitted photons (AMOC: Age Momentum Correlation) and enhancing throughput. In addition, we are developing a high frequency post-accelerator to apply high energy pulsed positron beams with millimeter range to thick materials.

Speaker: Günther Dollinger

10:45 AM → 11:15 AM Coffee break

11:15 AM → 12:15 PM Plenary: Update by the MLZ Directorate and the MLZ User Committee

12:15 PM → 12:45 PM Plenary: Messages by KFN, ENSA, and LENS

12:45 PM → 1:45 PM Lunch

1:45 PM → 4:45 PM Poster Session

1:45 PM P-059: 22Na-Sample Setup for Single-Specimen Coincidence Doppler Broadening Spectroscopy

This paper describes the design, construction and testing of a new ${}^{22}$Na isotope based sample-source setup called Single Specimen Positron Annihilation Spectroscopy (SSPAS) for measurements at the Coincidence Doppler Broadening Spectrometer (CDBs) positioned at the NEutron induced POsitron source MUniCh (NEPOMUC) beam line. Coincidence Doppler Broadening Spectroscopy (CDBS) measurements allow the detection of vacancy like defects due to the intrinsic attraction of positrons to such lattice defects. SSPAS addresses many problems of the previously employed sandwich sample design. SSPAS only requires a single sample and supports a wide range of sample sizes.
The ratio between 1275 keV and 511 keV gammas measured was approximately halved indicating lower background introduced by 1275 keV gammas. Most importantly, measurements showed the absence of the Kapton source component typically tainting Positron Annihilation Spectroscopy (PAS) data gathered with the conventional sandwich method. SSPAS is vacuum capable and CDBS measurement times are in the order of several days. Compared to the sandwich method, SSPAS allows for more accurate and more versatile measurements than previously possible without relying on the positron beam line.

Speaker: Roland Prossinger (NEPOMUC)

1:45 PM P-004: A Scintillation Detector as a First Main Detector for PERC

The instrument PERC at the FRM II will soon be ready for commissioning. Like its predecessors PERKEO II and PERKEO III, it will measure the beta spectrum of neutron decay and determine several of its correlation coefficients. It aims to improve the precision by up to one order of magnitude over current best values. This enables testing the Standard Model and search for new physics via effective couplings.

PERC will observe neutron decay in an 8 m long neutron guide and a high magnetic field will guide the charged decay products to the main detector, positioned downstream of the experiment. To detect and correct for backscattering events, another detector system will be installed upstream of the decay volume. The PERC spectrometer is designed such that one can install different types of detectors as a main detector, for example a scintillation detector, a silicon detector or a magnetic spectrometer, all of which offer unique advantages. Building on the knowledge and expertise from using scintillation detectors in the PERKEO experiments, the first detector to be installed is a scintillation detector with a PMT photon readout on the backside.

We present Geant4 simulations on a possible design for this scintillation detector and the resulting light yield and uniformity.

Speaker: Karina Bernert (TUM)

1:45 PM P-077: A Small Amount of Sodium Difluoro(oxalate)borate Additive Induces Anion-Derived Interphases for Sodium-Ion Batteries

In sodium-ion batteries (SIBs), the properties of the electrode-electrolyte interphases (EEIs) formed on the electrode surface, dominate the Na+ de-solvation process and Na+ (de)intercalation behavior, thereby influencing the battery performance. Currently, both high-concentration electrolytes and localized high-concentration electrolytes facilitate the formation of anion-derived and inorganic-rich interfacial chemistry, leading to excellent electrochemical performance. However, the expensive lithium salt and/or fluorinated diluent imposes a major concern. Herein, a small amount additive of 0.5 wt% sodium difluoro(oxalate)borate (NaDFOB) is introduced into 1 mol L–1 NaClO4/propylene carbonate electrolyte to construct a robust inorganic-rich EEIs via an anion preferential adsorption-decomposition mechanism. Results reveal that the DFOB– anion has a lower adsorption energy than the other components, which will be preferentially adsorbed in the inner Helmholtz plane (IHP) with the closer proximity to two electrode surfaces and thus being firstly decomposed to form inorganic-rich interphases, thereby effectively suppressing side reactions. Consequently, both Na-ion half-cells and full-cells using this electrolyte deliver excellent cycling performance. This strategy that regulates the interphase chemistry on the electrode surface through an anion preferential adsorption-decomposition strategy, provides a promising avenue for developing long-term cycling SIBs.

Speaker: Lan Xia (Technische Universität München)

1:45 PM P-030: Analysis of Neutron Diffraction Patterns for the Identification and Quantification of Crystalline Phases

Crystalline phases are determined by analyzing their neutron diffraction patterns. Typically, this is achieved by detecting the peak positions and intensities of a diffraction pattern, followed by measuring the similarity between these extracted information and records of known phases stored in a reference database.
The aim of this study was to use deep learning approaches to automatically identify phases without depending on a reference database. A comparative benchmarking of these methods was conducted, demonstrating their ability to effeciently and accurately classify crystalline phases.

Speaker: Loubna Kadri

1:45 PM P-086: Annihilation-gamma spectra of magnetically confined positrons scattering, cooling, and forming positronium

We present the time and energy spectra of the annihilation gammas of magnetically confined positrons undergoing collisions and charge exchange with background gas, He, and $\mathrm{CF_4}$ . The spectra are collected by a BGO (Bismuth Germanate) detectors in low-gain and high-gain mode. In high-gain mode, three detectors collect pile-up signals from timed electrostatic ejections. In low-gain mode, a 21-BGO (Bismuth Germanate) detector array situated in re-entrant ports 1 cm from the confinement volume detects ~10,000 gammas per shot. FPGA processing timestamps detections to 8 ns accuracy and records photon energy with 66 keV resolution. The spectra reveal elastic collision rates, inelastic cooling times, and a shift in the loss mechanism from positronium formation to collisional transport to the wall. This work opens the way for studying e+ diffusion in inhomogeneous fields, as well as e+ and positronium interactions with confined electrons and ions, which is essential for interpreting astrophysical and solar annihilation spectra.

Speaker: Jens von der Linden

1:45 PM P-008: APEX-LD: a levitated dipole trap for the confinement of an electron-positron pair plasma

Magnetic dipole traps have demonstrated good confinement properties for both non-neutral and quasi-neutral plasmas, making this a highly suitable type of trap for the creation and study of low-temperature, long-lived electron-positron pair plasmas. To generate such a plasma, the APEX (A Positron-Electron eXperiment) Collaboration is planning to inject positrons (supplied by the reactor-based beam NEPOMUC, then collected into pulses in a buffer-gas trap) into a compact levitated dipole magnetic field (APEX-LD), which is previously loaded with a comparable population of electrons. The dipole field of APEX-LD arises from a persistent current within the “floating coil” (F-coil): a 15-cm-diameter, closed, high-temperature superconducting (HTS) coil. To avoid the use of mechanical supports the F-coil is levitated from above by an open, copper “lifting coil.” A second HTS “charging coil” inductively charges the F-coil to a magnetic flux density on-axis of B = 0.5 T. Feedback-stabilization, implemented on a FPGA controller, enables over three hours of levitation. The design of APEX-LD, and magnetic field line visualizations from initial confinement experiments are presented. The future addition of an actively-cooled thermal radiation shield surrounding the trapping region will slow the resistive decay due to thermal warming, therefore increasing levitation time. This shield will also host the electrodes required to steer cold, dense pulses of e+ on to confining field lines.

Speaker: Alexander Card (Technische Universität München)

1:45 PM P-064: Application of Machine Learning in Event-Mode Neutron Imaging

The application of artificial intelligence (AI) is a growing field, especially with artificial neural networks (ANN). These tools are helpful for various applications, one of them being the optimization of data processing routines for detectors, from only optimizing classical processing algorithms in speed and efficiency to paving the way to new possibilities.
With this perspective in mind, we apply such ANNs to a novel type of neutron imaging detector: event-mode detection. The goal is the recreation of a part of the data processing routine. In particular, the reconstructing of scintillator events from scintillation photons.
This recreation of the classical algorithm was tried with convolutional neural networks (CNN). The current performance evaluation of these ANNs does not yet yield sufficient results to reach the set goal. So far only a general area of events could be successfully reconstructed by the ANN. Though the chosen approach and simplifications limited the current performance, they unveiled insights into changing the ANNs topology and the bounds of the CNNs in use.
In light of the fact that the AI does not reach the full performance of the classical algorithm so far, the results show loose proof of concept, and the general idea prevails. It is suspected that changes in the currently tried ANNs can solve the exposed problems completely. Therefore, opening a possibility for further inquiry, in addition to giving a perspective of surpassing the classical approach.

Speaker: David Schmid (FRM2-NECTAR)

1:45 PM P-017: Biopolymer-Templated Deposition of Hierarchical 3D-Structured Graphene Oxide/Gold Nanoparticle Hybrids for Surface-Enhanced Raman Scattering

Cellulose, a well-known natural biopolymer, possesses numerous advantages such as cost-effectiveness, renewability, ease of processing, and biodegradability [1]. Due to these inherent merits, cellulose has emerged as a promising bio-based substrate capable of synergistically combining with conductive materials (e.g., metals or carbon-based materials) for diverse applications including sensors, smart windows, and bioelectronics [2]. Typically, surface-enhanced Raman scattering (SERS), an advantageous analytical technique, allows for the rapid detection and structural analysis of biological and chemical compounds through their spectral patterns in nanotechnology [3]. Crucial for SERS is fabricating the substrates with strong and reproducible enhancements of the Raman signal over large areas and with a low fabrication cost. Herein, we present a straightforward approach utilizing the layer-by-layer spray coating method to fabricate (CNF) films loaded with gold nanoparticles (AuNPs) and graphene oxide (GO) to serve as SERS substrates. To investigate the fundamental mechanisms of enhanced SERS performance, grazing incidence small-angle X-ray scattering (GISAXS) technique combined with the machine learning random forest method is employed to identify different nanostructures for predicting vibrational frequencies and Raman intensities. Therefore, our approach provides a reference for facile and scalable production of universally adaptable SERS substrates with exceptional sensitivity

Speaker: Yingjian Guo (Deutsches Elektronen-Synchrotron DESY)

1:45 PM P-055: Challenges at the Li Metal/solid electrolyte interfaces for solid-state lithium batteries

Both LLZO and LATP are leading solid state electrolyte candidates because of their excellent characteristics, such as high ionic conductivity and wide electrochemical stability windows. However, their interfaces with Li metal anodes face stability challenges which hinders their application in solid-state lithium batteries.
In case of LLZO, we explore the differences between Al- and Ga-doped LLZO when interfaced with Li metal, and show that formation of Li metal interface with Ga-doped LLZO leads to a propensity of Ga to move from LLZO and form Ga-Li alloy layers, resulting in loss of dopant and associated changes in structure and electrochemical behavior not present in Al-doped LLZO. Neutron diffraction reveals that doping of LLZO with Ga results in complete transformation of the cubic phase to tetragonal phase when in contact with lithium metal.
In case of LATP, we overcome the chemical instability of LATP against Li, using a ultrathin PSiO polymer, which serves as multifunctional protection layer to enhance the interfacial stability between LATP and Li. It effectively blocks the direct contact between Li and LATP, regulates the homogeneous Li+ flux at the interface, promotes the intimate contact between PSiO and Li0 by forming Si-O-Li bonds, and generates an LiF-enriched interphase. As a result, it enables superior rate capability and cycling stability. Neutron depth profiling proves capability to measure the thickness of such a ultrathin layer.

Speaker: Dr Neelima Paul (Technical University of Munich, Heinz Maier-Leibnitz Zentrum (MLZ))

1:45 PM P-002: Characterizing an electron plasma into a levitated dipole to understand future positron injection and creation of positron-electron plasma

The APEX collaboration seeks to create positron-electron plasma by injecting positrons into an electron plasma, a thorough understanding of the electron plasmas. We present design and initial tests of a new diagnostic for the APEX-LD, which enables the measurement of the electric potential of the trapped plasma by injecting electrons along the axis. This information will augment the information garnered from the image charge signal on wall probes to yield a more complete picture of the equilibrium and the dynamics of the trapped plasma.
Further investigation into the behaviour of the stable toroidal mode in the levitated dipole and the transition into the unstable chirping mode are shown through the frequency of the electron plasma measured by image charges at the wall of the chamber.

Speaker: Veronika Bayer (IPP APEX)

1:45 PM P-069: Chemical Analysis with Neutrons at MLZ

At MLZ, various methods are available for chemical analysis with neutrons which enable highly sensitive determination of the element composition in a wide range of sample matrices. The classic methods of prompt gamma activation analysis and instrumental neutron activation analysis are available at the PGAA and NAA instruments. In addition, setups for neutron depth profiling (NDP), in-beam neutron activation analysis (iB-NAA) and prompt gamma-ray activation imaging in combination with neutron tomography (PGAI-NT) have been successfully established in recent years. Further approaches are under development, such as in-beam liquid scintillation counting (iB-LSC) and cyclic in-beam neutron activation analysis (ciB-NAA). We present the current and future possibilities of the methods.

Speakers: Dr Christian Stieghorst (TUM / FRM II), Dr Zsolt Revay (PGAA)

1:45 PM P-011: Commissioning of a polarized eV pulsed neutron beam and current mode gamma detector array at LANSCE

We developed a modular apparatus to polarize neutrons in situ at the Los Alamos Neutron Science Center using spin-exchange optical pumping. This technique requires the use of a glass cell filled with helium-3 gas and rubidium metal, which is heated until the rubidium is vaporized. An external magnetic field is applied, and the rubidium vapor is excited using a 795 nm, 50 watt laser, which is split to illuminate both ends of the cell. The rubidium exchanges spin with helium-3 gas, which, in an external magnetic field, has a spin-dependent neutron-nucleus cross section. This effectively filters out one spin state of the neutrons provided by the pulsed neutron beam, resulting in a neutron beam with a net polarization.

We also developed a current-mode gamma detector array composed of 24 NaI detectors. In the center of the detector array is a spin-transport tube, which is composed of a solenoid that maintains the spin state of the neutrons as they travel through the array. At the center of the tube is the location of the target material for the polarized neutron beam. The tube is wrapped in lithium-6 enriched plastic and powder to absorb scattered neutrons before they are able to reach the detector array. The array itself is also surrounded by lead bricks and borated polyethylene to prevent neutrons scattered in the beamline from hitting the detectors.

Speaker: Kylie Dickerson (Indiana University)

1:45 PM P-062: CREScent: characterization and advances

The PERC (Proton and Electron Radiation Channel) experiment is part of the new generation of high-precision measurements of angular correlations in neutron beta decay. Among the different approaches, the CRES (Cyclotron Radiation Emission Spectroscopy) technique is a perfect match for PERC, given it provides a highly precise frequency-based electron spectroscopy and it is non-destructive. The CREScent experiment is a proof-of-principle experiment, aiming to combine the CRES-technique with the signal amplification qualities of a RF cavity, naturally compensating for the extremely weak power of the expected radiation pulses. In order to do so, a proper characterization of the cavity, electron beam and magnetic field, as well as their interactions, must be performed.

Speaker: Alberto José Saavedra García (Atominstitut - TU Wien)

1:45 PM P-079: Crosslinking mechanisms in solutions of alginate-based graft copolymers with thermoresponsive side chains

Alginates are naturally occurring polysaccharides extracted from brown algae which are of interest for various biomedical applications$^{[1]}$. In aqueous alginate solutions, divalent cations such as Ca can cause the formation of a polymer network due to the attractive ionic interactions between the cation and the negatively charged carboxyl group on the alginate chains. Grafting thermoresponsive side chains on alginate provides a second crosslinking mechanism, triggered by heating above the collapse temperature of the side chains$^{[2]}$. In the present case, the side chains are random copolymers from poly(N-isopropylacrylamide) (PNIPAM) and the hydrophobic poly(N-tert-butylacrylamide) (PNtBAM)$^{[3]}$. The present study aims to investigate the effect of these crosslinking mechanisms on the conformation of such alginate-based graft copolymers in dilute solution. Temperature-resolved dynamic light scattering experiments in the presence or absence of Ca were conducted to determine the hydrodynamic radius. In a dilute solution at room temperature, Ca is found to reduce the hydrodynamic radius of the graft copolymers via intramolecular crosslinking. The presence of Ca has no effect, neither on the collapse temperature nor on the hydrodynamic radius of the collapsed copolymer chains.

References
1. R. Abka-khajouei et al., Mar. Drugs 2022, 20, 364.
2. Y. N. Dahdal et al., Polymer 2016, 85, 77.
3. K. Safakas, C. Tsitsilianis et al., Int. J. Mol. Sci. 2021, 22, 3824.

Speaker: Wenqi Xu (Technical University of Munich, TUM School of Natural Sciences, Soft Matter Physics Group)

1:45 PM P-071: DAPHNE Vision

As part of the DAPHNE4NFDI project, the DAPHNE Vision network promotes the cross-community collaboration among young scientists working on data processing with photon and neutron sources. It encourages the exchange of knowledge and experiences, helping participants benefit from each other's expertise and fostering new ideas and solutions.

DAPHNE Vision also aims to adapt solutions to current challenges faced by its members, ensuring practical application of advanced data management and analyzing methods. The network serves as an incubator for future ideas within the DAPHNE4NFDI framework, supporting long-term collaboration and innovation, and wants to engage PhD students in data processing.

The first DAPHNE Vision meeting was held on November 11th and 12th at the University of Göttingen, gathering participants from across Germany.

Speaker: Christian Trageser (Forschungszentrum Jülich)

1:45 PM P-066: Defect evolution in additively manufactured components with neutron grating interferometry (nGI)

Additive manufacturing (AM) has become increasingly popular in different applications where complicated geometries, weight reduction, and customized performance are desired. The additive nature of manufacturing provides an edge over conventional manufacturing processes regarding complex shapes, customized designs, and depositions. Internal defects like lack of fusion (LOF), cracks, and voids are major problems contributing to the part failure of additively manufactured parts. Tensile residual stress (TRS) developed due to high-temperature gradients and defects also affects the performance of the fabricated parts. It was found LOF defects can only be detected by neutron grating interferometry (nGI). nGI in ICON beamline, PSI is used to study the in-situ defect evolution of additively manufactured IN718 materials under tensile loading using FRM II tensile rig. Defect growth and crack growth propagation are also analyzed using nGI tomography to gather 3D information on the crack propagation zone. Microstructural analysis, defect, crack growth, and fractography study are also performed using destructive classical techniques such as optical microscopy and SEM, to complement the nGI non-destructive testing.

Speaker: Sapam Ningthemba Singh (FRM II, Technical University of Munich)

1:45 PM P-052: Design of a triple-cooling assembly for high purity germanium detectors for Coincidence Doppler Broadening Spectroscopy

Coincidence Doppler Broadening Spectroscopy requires the use of high purity Germanium detectors cooled to approximately 100K as these possess an excellent energy resolution for the analysis of the positron-electron annihilation radiation. To increase the overall detection efficiency the available solid angle should be covered by as many detectors as possible. Conventional cooling with large dewars, as in the current setup, would limit the total number of detectors, and filling many of them with liquid nitrogen would be impractical. For this reason, a novel approach was pursued in which multiple dewars are replaced by a pivoting, flexible cooling rod arrangement for three detectors connected to a cryo-cooler. In this contribution, the design and first tests will be presented.

Speaker: Patrick Oberländer (TUM/FRM2 NEPOMUC)

1:45 PM P-070: DEVA - Data Evaluation Group

The Data Analysis group DEVA was established in 2022. It provides support for processing and analyzing experimental data recorded with MLZ instruments. This service is specifically designed to support occasional and new users. In this context, the group also assists in the preparation of related publications. Currently, DEVA covers diffraction, small-angle scattering, imaging and elemental analysis methods on the instruments SPODI, STRESS-SPEC, SANS-1, REFSANS, ANTARES, PGAA (including NDP method) and NAA. It will be extended to further methods soon. Another well-received activity is the organization of workshops on various data analysis software. We report on the work of the group over the last years and give an outlook on future plans.

Speakers: Dr Christian Stieghorst (TUM / FRM II), Joana Rebelo-Kornmeier, Dr Neelima Paul (Technical University of Munich, Heinz Maier-Leibnitz Zentrum (MLZ))

1:45 PM P-034: EasyTexture: a new software for data reduction at POWTEX

POWTEX is a high-intensity time-of-flight diffractometer for POWder and TEXture analysis, which will serve the needs of the solid-state chemistry, geoscience, and materials science communities. The important part of the data processing workflow at POWTEX is data reduction, which implies a correction of the collected data by experimental artifacts that are caused by the instrument itself or its environment. In our work, we concentrate on the development of workflow for reduction of texture samples. In particular, we present a new open-source software called EasyTexture. The software performs a set of data reduction algorithms at POWTEX and prepares texture intensity resolved spectra for analysis within the MAUD package [1]. The user-friendly graphical interface of EasyTextrure is designed based on the EasyScience framework [2], which provides tools for creating intuitive and comprehensive interaction experience for its users.

[1] Lutterotti, Luca, et al., Z. Kristallogr. Suppl. 26 (2007), 125
[2] https://easyscience.software

Speaker: Oleksandr Koshchii (JCNS at MLZ, Forschungszentrum Jülich GmbH)

1:45 PM P-019: Electric field-assisted positron annihilation lifetime spectroscopy: Investigation of interface regions in thin-film Metal-Oxide-Silicon capacitors

Defects at internal interfaces pose a major concern for layered heterostructures. For example, in a MOSFET the defects at the SiO2/Si interface can introduce charge traps, which can degrade the electronic performance of the device. The defects in Metal-Oxide-Silicon (MOS) systems were extensively researched using depth-resolved beam-based positron-annihilation techniques. Unfortunately, the investigation of interfaces with a thickness of less than 5 nm is not a trivial task. This is due to the small extent of the interface compared to the implantation profile of monoenergetic positrons provided by large-scale facilities such as NEPOMUC or ELBE. In the past, efforts were made to manipulate the positron diffusion by applying an external electric field to various layered systems. The electric field leads to the drift of thermalized positrons towards the interfaces.
In this work, we present a positron drift experiment on a MOS system biased from -30 V (accumulation) to +30 V (depletion) investigated by electric field-assisted Positron-Annihilation Lifetime Spectroscopy (PALS). The results show, that the in-situ application of a sample bias, which is also available at the PLEPS, is a promising addition to the common positron annihilation methods to investigate ultra-thin structures such as interfaces.

Speaker: Ricardo Helm (Universität der Bundeswehr München)

1:45 PM P-010: Facet-dependent photovoltaic efficiency and stability variations in mixed Sn-Pb perovskite solar cells

Since the first breakthrough of perovskite solar cells by using a solid-state structure, the solar cell’s power conversion efficiency has increased from 9.7% to >26%. These exciting improvements are mainly attributed to achieving a pinhole-free thin film at the beginning and an increased understanding of microstructures on perovskite thin films. In addition, the rapid PCE improvement has been accompanied by an increased understanding of microstructures on perovskite thin films. The photovoltaic performance of PSCs has been found to strongly correlate with their facet orientations. For example, the charge carrier lifetime, open-circuit voltage deficit and device hysteresis of PSCs are related to the structure and density in (111) crystal facets of perovskite. Besides, different crystal facets have different atomic arrangements and coordination, which lead to different atomic potential landscapes and, subsequently, to different electronic, physical, and chemical properties. Nevertheless, the deep understanding of perovskite thin films, especially the crystal facets of the thin film, still lags behind that of single-crystal samples or other inorganic thin films. In this work, we prepare the mixed tin-lead perovskite film with different orientations according to the facet engineering. We research the role of the different perovskite crystal facets in stability and optoelectronic properties.

Speaker: Ms Xiaojing Ci (Technische Universität München)

1:45 PM P-018: FIREPOD: A new thermal high-throughput powder diffractometer at MLZ

The new instrument FIREPOD (FIne REsolution POwder Diffractometer) was successfully transferred from Berlin to Garching as part of a BMBF-funded project. At the MLZ,it will have a ‘second life’ as a dedicated high-throughput instrument, ideally suited for a wide range of fast parametric studies and studies with large sample series. As such, it perfectly complements the group of three unique thermal powder diffractometers located at the SR8 beam tube of the FRM II. Due to the optimised design of the detector, even very bulky sample environments can be used. The scientific focus will be on advanced materials research, including topics with promising industrial applications such as batteries, hydrogen storage, or construction and functional materials under a wide range of conditions, particularly in situ and in operando studies. The details of the instrument design and its forseen capabilies will be presented in detail.

Speaker: Christoph Hauf

1:45 PM P-045: Focusing with a nested mirror optic on the thermal triple-axis spectrometer PUMA at MLZ

A persistent challenge for inelastic neutron scattering is the low scattering cross-section of neutrons, necessitating larger sample sizes compared to other techniques. Focusing the neutron beam is a viable method to increase the flux and the nested mirror optic (NMO) is an ideal solution, providing a small, well-behaved beam at the sample position while maintaining space for sample environment equipment. At the thermal TAS PUMA at MLZ, the new NMO will decrease the beam size from about 20mm x20mm to 5mm x 5mm at the sample position while preserving 50% of the incoming neutrons, resulting in an 8-fold increase in flux on small samples. The McStas neutron simulation package offers a general tool for Monte Carlo simulations of neutron scattering instruments and experiments. We have built a user-friendly GUI for simulating the PUMA instrument with McStas, including the new NMO optics, enabling the simulation of neutron scattering experiments on a virtual PUMA instrument. The virtual instrument is useful for staff and users (testing optics, simulating experiments to test instrument parameters and acquire resolution functions) as well as for students (learning platform for neutron scattering, practice alignment). We will discuss the NMO setup for PUMA, along with the scientific case for this device, highlighting several planned use cases. Additionally, we will showcase the progress on the McStasScript-PUMA integration and discuss the planned features and capabilities.

Speaker: Adrian Merritt (Karlsruher Institut für Technologie)

1:45 PM P-028: Gas quenching process under ambient conditions for stable and efficient inverted perovskite solar cells

Inverted perovskite solar cells have gained significant attention due to their potential for high efficiency and stability. In the process, the active layer fabrication plays a key role in determining the performance of the solar cells. Gas quenching is an important technique in the preparation of perovskite solar cells, as it enhances film quality and cell performance by precisely controlling crystal growth and minimizing defects. This study explores the optimization of gas quenching under ambient conditions to enhance the quality of perovskite films. By systematically varying the quenching parameters, such as gas flow pressure and how long the gas flow is sustained, we demonstrate how a precise control over these conditions can improve the crystallinity and uniformity of the FA0.8Cs0.2Pb(I0.6Br0.4)3 layer. In this work, the influence of different ratios of DMF: NMP on the performance of gas-quenching assisted FA0.8Cs0.2Pb(I0.6Br0.4)3 solar cells are also explored. This approach provides a practical solution for scaling up the production of high-performance inverted perovskite solar cells while maintaining operational stability in real-world environments.

Speaker: Zhaonan Jin

1:45 PM P-056: Heterogeneity of Lithium Distribution in the Graphite Anode of 21700-Type Cylindrical Li-Ion Cells during Degradation

The electrochemical cycling of lithium-ion batteries proceeds through an active exchange of lithium ions and electrons between the cathode and anode materials. Besides material properties, such exchange is facilitated by cell parameters like electrode dimensions and geometry, current density, temperature, pressure, reaction rate, etc. Such parameters are neither uniformly distributed nor static in general and, therefore, serve as stabilizing factors of heterogeneous states in Li-ion batteries typically reflected in the lithium concentration distribution in the electrodes [1].
In previous studies, it was shown that with cell aging, the distribution of the lithium-ions in the graphite anode of 18650-type lithium-ion batteries changes [2]. In this contribution, the heterogeneity of a fresh and aged 21700-type Li-ion battery was investigated using multiple diffraction techniques with both synchrotron and neutron radiation. Measurements were completed using lab-based measurements like SEM, incremental capacity analysis, etc. The results have shown an interesting lithium distribution after cell aging, leading to the question of how the cell format influences the cell aging behavior.

1. Senyshyn, A., et al., Homogeneity of lithium distribution in cylinder-type Li-ion batteries. Scientific Reports, 2015. 5(1): p. 18380.
2. Mühlbauer, M.J., et al., Inhomogeneous distribution of lithium and electrolyte in aged Li-ion cylindrical cells. Journal of Power Sources, 2020. 475: p. 228690.

Speaker: Dominik Petz

1:45 PM P-020: High-efficiency diffractometer ERWIN

The instrument ERWIN, currently being assembled at the MLZ, is a high-efficiency diffractometer designed for rapid data collection, time-resolved measurements, parametric studies and investigations on small samples. ERWIN is characterized by a large two-dimensional wire chamber detector with a virtually seamless coverage of 135° and a vertical angle range of 15° which will allow the characterization of powder samples, textured bulk samples and single crystals. The spectrum of applications ranges from time- and spatially-resolved investigations of battery materials to the kinetics of hydrogen storage materials and deformation mechanisms of engineering materials under the influence of external loads. In this contribution we will present the scientific applications, specifications, current developments and planned expansion stages.

Speaker: Markus Hoelzel

1:45 PM P-065: High-resolution powder diffractometer SPODI

SPODI, the Structure Powder Diffractometer at the Heinz Maier-Leibnitz Zentrum in Germany, is a high-resolution neutron powder diffractometer used for the precise determination of crystal and magnetic structures as well as microstructural properties of materials. It features an optimized instrument geometry and advanced detector system, providing high angular resolution and allowing researchers to detect subtle structural features and phase transitions. Equipped with a position-sensitive detector, SPODI enables rapid data collection and studies of materials under varying conditions, such as temperature, electric and magnetic field, applied load etc. It plays a vital role in understanding complex materials like energy materials and magnetic materials, contributing to the development of materials with tailored properties. SPODI also emphasizes user collaboration, offering support for experiment programs and data analysis, which fosters diverse research projects across scientific fields.

Speaker: Anatoliy Senyshyn

1:45 PM P-046: Hot Neutron Single Crystal Diffraction on HEiDi: New Applications and Perspectives

The single-crystal diffractometer HEiDi at MLZ offers a broad spectrum of thermal and hot neutrons, excellent resolution, access to a large region of reciprocal space, low absorption and high sensitivity for light elements, making it a versatile tool for extended studies on many structures for nowadays topics in solid state physics, chemistry & mineralogy.
A key feature of HEiDi is its sample environment: Low T measurements are possible down to ~2 K, e.g. to study magnetic structures of rare earth orthoferrites (DFG SA 3688/1-1). A mirror furnace allows not only high T measurements up to 1300 K but also dedicated gas atmospheres to study light elements in potential battery materials, e.g. excess oxygen incorporation in brownmillerites and layered perovskites (DFG ME 3488/2-1) for a better understanding of the underlying diffusion processes and related structural and electronic changes. An optimization for tiny samples << 1 mm³ and high pressure cells within two BMBF projects (BMBF 05K16PA3, 05K19PA2) enables isotropic HP experiments up to 10 GPa, even at low temperatures, as new application and allowed development of a small Li-glass based area detector (PSD) prototype optimized for short λ.
As future extension of HEiDi’s capabilities we plan a wide angle version of this PSD. Access to large Q matches perfectly the growing need for total scattering studies, offering PDF analysis (pair distribution function) to study locally disordered functional materials as new application.

Speaker: Dr Martin Meven (JCNS/FZJ)

1:45 PM P-041: Imaging from meV to MeV Neutrons combined with Gamma Imaging at the NECTAR Instrument

Located at the SR10 at the FRM II, NECTAR is a versatile instrument and designed for the non-destructive inspection of various objects by means of fission neutron radiography and tomography. Compared to the Z-dependency of X-ray and gamma imaging, fission neutrons have the strong advantage of often providing similar contrast for heavy and light materials. Only few facilities around the world provide access to well collimated fast neutrons, with NECTAR at the FRM II being the only instrument that has a dedicated user program for fast neutron imaging. Aside from fast neutrons, thermal neutron as well as gamma imaging is possible by using different scintillator materials with the same detector system, extending NECTAR’s imaging capabilities to different modalities.
Here, we present the most recent upgrades to the NECTAR beam-line, including unparalleled elemental imaging capabilities as well as recent progress in event-mode imaging with fast neutrons.

Speaker: Adrian Losko (Technische Universität München, Forschungs-Neutronenquelle MLZ (FRMII))

1:45 PM P-049: Impact of hydrogen on a polycrystalline CoNiCr-based superalloy

Hydrogen plays a crucial in the ongoing transformation of the energy and mobility sector and is expected to become increasingly significant as a fuel for gas turbines. Key components of gas turbines are constructed from superalloys, making it essential to understand the impact of hydrogen on these high-temperature materials.
In this study, hydrogen embrittlement in a CoNiCr-based superalloy is investigated using a combination of NanoSIMS measurements, synchrotron and neutron diffraction, and analysis of fractured tensile samples from hydrogen-charged specimens. NanoSIMS mapping revealed the highest hydrogen concentration localized within the grain boundary pinning µ precipitates, a finding corroborated by synchrotron diffraction measurements showing significant lattice expansion of the µ phase after hydrogen charging.
Neutron diffraction experiments further indicate that the γ' phase absorbs more hydrogen than the γ phase, resulting in greater expansion and an increased lattice misfit between the γ and γ' phases.
Tensile tests demonstrate a pronounced influence of hydrogen on the mechanical properties of samples charged with high-pressure hydrogen. The presence of hydrogen within µ phase particles and at the γ/γ' interface promotes considerable crack initiation at the boundaries of the µ phase and facilitates crack propagation along weakened γ/γ' interfaces.

Speaker: Mr Oliver Nagel (Friedrich-Alexander-Universität (FAU) Erlangen-Nürnber)

1:45 PM P-015: in hospice adaptation of photosynthetic membranes of Symbiodinium to rising seawater temperatures

Symbiodinium is the photosynthetic endosymbiont of coral polyps. Rising seawater temperatures are associated with the mass expulsion of Symbiodinium from coral, the so-called “coral bleaching” events. Hard corals, such as Acropora cervicornis (staghorn coral), provide an important contribution to the coral reef ecosystem. Small angle neutron scattering (SANS) provides a unique perspective on actively metabolizing photosynthetic organisms and in particular the organisation of photosynthetic membranes within the cell[1].` Slavov et al.,[2] have provided a detailed structural hypothesis on the response of Symbiodinium to elevated temperatures and the need to provide relief from thermal stress by rearrangements of the photosynthetic membranes. Modelling of SANS data with a triple vesicle model based on literature understanding provides details of the structural rearrangements of the photosynthetic membranes of Symbiodinium. As well as providing as means to provide analysis of SANS curves from the environmentally important dinoflagellate Symbiodinium these results importantly show the utility of SANS as a structural tool in probing the response of photosynthetic organisms to environmental stress.

1.Y. Li, et al.,, Biochimica Et Biophysica Acta-Bioenergetics 1857 (1), 107-114 (2016).
2.C. Slavov et al., Biochimica et Biophysica Acta (BBA) - Bioenergetics 1857 (6), 840-847 (2016).

Speaker: Christopher Garvey (MLZ)

1:45 PM P-039: In situ synchrotron X-ray diffraction study of deformation behaviour of Ti-6Al-4V-Mo alloys manufactured using Laser Powder Bed Fusion

Laser-based additive manufacturing processes involve complex cyclic thermal history characterized by directional heat dissipation, large temperature gradient, repeated melting and rapid solidification. This leads to the formation of strong crystallographic texture for the prior β grains and brittle martensitic microstructure in Ti-6Al-4V. Consequently, the as-built Ti-6Al-4V parts show low ductility <10%, low rate of work hardening, and limited fatigue strength, which are unsatisfactory for aerospace applications. Therefore, the development of new alloys exhibiting a good combination of strength, ductility, and work hardening tailored for rapid solidification processing conditions is required.
In this study, in-situ alloying is explored for Ti-6Al-4V-Mo alloys during Laser Powder Bed Fusion to achieve desired phase compositions and phase stabilities, ensuring a good combination of strength and ductility. During uniaxial tension, in-situ high-energy synchrotron X-ray diffraction (HE-SXRD) was performed to track the deformation processes and mechanisms of stable and metastable Ti alloys. The results obtained gain new insights into how locally tuned phase stability influences the deformation behavior of additively manufactured Ti alloys, which facilitates the microstructural design when exploiting the TRIP effects.

Speaker: Guichuan Li (KU Leuven)

1:45 PM P-033: Influence of Azobenzene Moieties on the Swelling Behavior of Poly(Dimethylacrylamide) Films in Water Vapor under UV-Irradiation

In this study, we investigate the swelling characteristics of p(AzAm-co-DMAm) films in both isomer states of the photoswitchable molecule azobenzene (Az). The influence of UV-irradiation on the swelling behavior in water vapor is explored, aiming to control water uptake, expansion, and morphology on the nanoscale. The material holds promise for applications such as light sensors, photo-actuators, and drug-delivery systems. We use time-resolved FTIR spectroscopy to analyze group vibrations during swelling and irradiation, obtaining insights into the molecular interactions during the isomerization process. Additionally, by utilizing in situ time-of-flight neutron reflectometry on a thin film at the D17 instrument at ILL, we obtain time- and depth-resolved data about the water distribution. Our results reveal insights into how azobenzene moieties affect the microscopic properties of the polymer.

Speaker: David Kosbahn (TUM E13)

1:45 PM P-083: Insights into the Cyclability of LiF-Coated LiNi0.9Co0.05Mn0.05O2 Cathodes in Sulfide-Based All-Solid-State Batteries

All-solid-state lithium batteries (ASSLBs) have gained increasing attention as a potential alternative to conventional liquid electrolyte-based lithium-ion batteries (LIBs), yet still face significant challenges, particularly at the cathode|electrolyte interface. In this study, the surface of a Ni-rich LiNi0.9Co0.05Mn0.05O2 (NCM90) cathode was modified with a lithium fluoride (LiF) coating to enhance interfacial stability and cycling performance, using argyrodite Li6PS5Cl as the solid electrolyte.

The LiF coating was applied using both solid-state and liquid-state methods, with optimization of the sintering temperature at 700 °C. Detailed characterization, including XRD, SEM, and EDXS, confirmed the preservation of the cathode's bulk structure and the successful application of the LiF coating. The electrochemical performance of the coated cathode was evaluated, revealing that the 1% LiF coating prepared via the liquid-state mixing method significantly mitigated detrimental interfacial reactions, preserved ionic conductivity, and increased the cycling performance (reversible capacity, rate capability, etc.) and stability of ASSBs using argyrodite Li6PS5Cl as solid electrolyte.

Overall, the LiF-coated NCM90 cathodes exhibited superior performance, particularly when paired with the argyrodite Li6PS5Cl solid electrolyte, indicating the potential of surface modification strategies to address interfacial degradation and advance ASSLB technology.

Speaker: Ziyan Zhang (kit)

1:45 PM P-009: Kinetics of nanostructural and interfacial evolution induced by photopolymerization for submicrometer additive manufacturing

Photopolymerization offers excellent spatial resolution, low energy consumption and high curing speeds, making it a widely used industrial technology with great potential in additive manufacturing application. The kinetics of spatial and temporal nanostructural evolution and the interfacial formation in resin multilayers are the key to achieve controllable and high-precision manufacturing. In detail, the photopolymerization-induced transformation of resins from as-deposited to solid and cross-linked state needs to be correlated to the physical transformations. Here, we use spin-coated UV-curable multilayer films as research model. We investigate the kinetics of the nanostructure and interfacial evolution by modulating precursor resin components (solvents, active diluents, and glass temperature conditioning agents). Combining atomic force microscopy (AFM), scanning electron microscopy (SEM), and grazing incidence small angle X-ray scattering (GISAXS), the UV-curing induced nanoscale morphology as well as the buried interlayer interface of the multilayer films are probed. We reveal the kinetics of solvent- and reactive diluent-induced interface evolution in photocurable multilayer film fabrication. This paves the way for sub-micrometer additive manufacturing with high precision and controlled nanomorphology.

Speaker: Shouzheng Chen (Physik-Department, Lehrstuhl für Funktionelle Materielien, Technische Universität München, James-Franck-Strasse 1, 85748 Garching, Germany)

1:45 PM P-013: KWS-2 Extended Q-Range SANS Diffractometer: Cold vs. Thermal Neutron Use

The KWS-2 is a classical pinhole SANS diffractometer for the investigation of complex mesoscale morphologies and rapid structural changes in soft condensed matter and biophysical systems. By combining pinhole mode, focusing mode with lenses and WANS mode with detection capabilities up to 2$\theta$ = 50°, the instrument enables exploration of a wide Q range from 2.0×10$^{-4}$ - 2.0 Å$^{-1}$ and offers high neutron intensities with MHz detection capabilities, low background and adjustable experimental resolutions in continuous or TOF mode. SEC complementarity for in-situ protein purification provides the instrument with controlled quality biological samples. Robotic systems with automatic sample changer at the sample position allow a continuous supply of samples to the instrument and the merging of experiments from different user groups when similar experimental conditions are required.
Due to current technical problems, the FRM II reactor will be temporarily operated without a cold neutron source. By combining McStas simulations and test measurements on model biological systems with short wavelength neutrons, $\lambda$= 2.8 Å, available due to the optimized properties of the neutron guide and the possibility to tilt the velocity selector, we demonstrate the performance of the KWS-2 in the thermal neutron regime of the FRM II reactor and the possibility to contribute significantly to the MLZ user program during the temporary absence of a cold source without interruption.

Speakers: Anastasiia Fanova (JCNS), Aurel Radulescu (Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ)

1:45 PM P-057: KWS-3 Very Small Angle Neutron Scattering Diffractometer: current status

KWS-3 "VerySANS" is a very-small-angle-neutron-scattering diffractometer using a focusing mirror to achieve a high Q-resolution 3·10$^{−5}$ $Å^{−1}$. In “standard mode” with Q-range between 10$^{−4}$ and 2.5·10$^{−3}$ Å$^{−1}$ KWS-3 demonstrates worldwide best performance: intensity much higher than any pinhole SANS instrument and measurement time much shorter than any Bonse-Hart camera. Over the last years, we have finalized a multi-sample-position instrument concept: we have been able to propose to users optimal configurations with high flux and low background covering three decades within Q-range 3·10$^{−5}$ and 3·10$^{−2}$ Å$^{−1}$ . We can also offer a "SANS" configuration for strongly scattering samples with sample-to-detector distance (D) between 5 and 40 cm covering the Q-range of a classical SANS instrument between 2.5·10$^{−3}$ and 0.35 Å$^{−1}$ . Tilt stages/rotation table for the sample environment (SE) up to 500 kg have been commissioned as a mobile device and could be used across the whole instrument Q-range. Polarized neutrons and a supermirror analyser represent a novel option now available. The operation of the instrument without a cold source will also be discussed.

Speaker: Dr Vitaliy Pipich (Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ Forschungszentrum Jülich GmbH)

1:45 PM P-063: Light Yield Linearity of the BC-408 Plastic-Scintillator under Electron Excitation

The PERC (Proton and Electron Radiation Channel) facility, located at the neutron source FRM II of the Technical University of Munich (TUM), serves as a clean source of neutron decay products, namely protons and electrons. PERC aims to contribute to the determination of the Cabibbo-Kobayashi-Maskawa quark-mixing element (V𝑢𝑑), measure the correlation coefficients of free neutron decay (𝑎, 𝐴, 𝑏, 𝐶) and to search for new physics at the TeV scale. While the main detector is a silicon detector, the backscattering detector system of PERC consists of two scintillation detectors with SiPM read-out.

The light output of the plastic scintillator BC-408 is investigated in the low-energy range (0–60 keV) using an electron gun as a beta source and a Silicon Photomultiplier (SiPM). This approach enables continuous testing of the nonproportionality of the light output to the amount of absorbed energy by the scintillator, without relying on the fixed energies of standard radioactive beta sources. Understanding this nonproportionality is an important aspect of the performance of a scintillation detector like the backscattering detector system of PERC. Additionally, the performance of the electron gun is compared to selected calibration sources.

Speaker: Johannes Schilberg (Atominstitut - TU Wien)

1:45 PM P-036: Liquefaction of Li-Mg-N-H hydrogen storage system by LiBH4 as a way to accelerate its dehydrogenation

Hydrogen storage in light hydrides for mobile applications is a widely discussed but highly controversial topic. Is it safe enough? Is it effective enough? Does hydrogen energy have a future? The questions are numerous and multifaceted but almost none of them has a clear answer so far. A complex hydride system 6Mg(NH2)2:9LiH with LiBH4 as a dopant is one of promising candidates on a role of on-board hydrogen storage, since it it actively decomposes already at the 180oC, releasing only hydrogen. The role of the LiBH4 is expressed in forming of an low-melting liquid-phase with high hydrogen mobility with an intermediate product LiNH2, which highly enhances the rate of the dehydrogenation reaction. There are 2 mixed phases with a high Li-ion conductivity described: a metastable Li2BH4NH2 and a peritectically melting Li4BH4(NH2)3, and both of these phases were registered while performing DSC and XRD measurements. This 2-component system is investigated and a number of ratios was analyzed and thereupon a phase diagram was created. Its lowest melting point, i.e. eutectic point is located at 33% LiNH2 and at 90oC. The behavior under heating and the intrinsic structure of this eutectic composition was investigated by neutron total scattering. The composition corresponding to this eutectic mixture would be 6Mg(NH2)2:9LiH:6LiBH4.

Speaker: Anastasiia Kuznetsova (WPN Hereon Garching branch)

1:45 PM P-076: Mapping Scintillation Light Distribution of Individual Neutron Interactions in Scintillator Screens using LumaCam Detectors

LumaCam detectors have a structure resembling many established scintillator-based imaging detectors. The key difference is the imaging chip being fast enough to identify the individual scintillaton photons produced by a neutron interaction in the scintillator screen. This information can be used to provide enhanced spatial and temporal resolution, as well as noise suppression and particle discrimination capabilities. These advantages have led to a rapid growth in the usage of LumaCam detectors in the recent years, especially for time-of-flight imaging applications. To fully utilize their potential, a detailed understanding of the spatial and temporal distribution of the scintillation light produced by neutrons as well as possible noise sources is required. We will present fundamental research on neutron scintillator screens, using LumaCam detectors to map the photon distribution of individual neutron interactions.

Speaker: Alexander Wolfertz (TUM FRM2)

1:45 PM P-048: Micrometer positron beam at the Scanning Positron Microscope

Positron annihilation lifetime spectroscopy (PALS) is a powerful tool in a wide range of material science. To investigate inhomogeneous defect distributions, e.g. close to fatigue cracks or dispersive alloy, with PALS a monochromatic pulsed positron beam of variable energy with a diameter in the range of 1 µm and a time resolution of 200 ps FWHM is needed.
To this aim, the Scanning Positron Microscope (SPM) was developed and built at the Universität der Bundeswehr. To overcome the limit of low count-rates the SPM was transferred to the intense positron source NEPOMUC at the MLZ in Garching. A sophisticated beam preparation, including multiple remoderation steps, is needed to reach a lateral resolution in the micro-meter range. An essential component of the interface is the positron elevator which compensates for the energy loss caused by the remoderation process without altering other important beam properties like time structure and brightness.
In this contribution, we will give an overview of the current status of the SPM, which has become a complete makeover during the reactor shutdown. In addition, the latest developments of the positron elevator and the newly developed frequency stabilization system are reported. To ensure proper operation of SPM at NEPOMUC, stable amplitude, stable frequency and stable phase of the RF-signal are crucial. Moreover, future applications of the SPM will be discussed.

Speaker: Johannes Mitteneder (Universität der Bundeswehr)

1:45 PM P-042: MIEZEPY: An Open-Source Tool for Efficient MIEZE Data Reduction

MIEZEPY is an open-source software package designed for the efficient reduction of data acquired in the MIEZE (Modulation of Intensity with Zero Effort) mode. MIEZE is a neutron resonant spin echo technique that enables the measurement of the intermediate scattering function, S(Q, τ), in depolarizing sample environments, such as under high magnetic fields. This technique is implemented at the RESEDA (Resonance Spin Echo for Diverse Applications) spectrometer at MLZ, which offers sub-µeV energy resolution and an exceptional dynamic range (~ 8 orders of magnitude). MIEZE generates a complex four-dimensional dataset that is easy to manipulate using the user-friendly, intuitive interface of MIEZEPY. Our software allows users to quickly reduce their data and extract S(Q, τ) in a streamlined, hassle-free manner!

Speaker: Iryna Lypova (TUM/FRM II)

1:45 PM P-073: Mulitplexing TAS measurements assisted by active learning

Three-axis spectrometers (TAS) are versatile instruments to study inelastic neutron scattering. They allow high energy resolution investigations of fundamental excitations across various energy and momentum coordinates. However, traditional TAS methods are limited by point-by-point measurement in reciprocal space, which can be time-consuming and less effective for rapid kinetic studies. A promising method to more efficient TAS measurements is the multiplexing technique, such as Multiplexing-PUMA at MLZ. This method allows simultaneous measurements across multiple (Q, E$_{f}$)-channels, enabling broader reciprocal space mapping while maintaining high data quality.
The ARIANE (Artificial Intelligence-Assisted Neutron Experiments) approach has proven effective in optimizing single-point TAS measurements [1]. By applying machine learning techniques, it improves data acquisition efficiency. Building on this foundation, we propose an innovative extension of the ARIANE framework for multiplexing measurements in TAS. This extended approach will employ an active learning algorithm to dynamically identify regions of interest in the (Q,ω)-space. It will suggest and measure 11 different locations, provided it complies with the physical constraints of the PUMA multiplexing setup. This will significantly enhance information gain and overall experimental efficiency, maximizing the utilization of neutron beam time for users.

Reference: [1] Parente et al., Nat. Comm. 14, 2246 (2023)

Speaker: Eugenio Vitale

1:45 PM P-084: Multipoint Anionic Bridge: Asymmetric Solvation Structure Improves the Stability of Lithium-Ion Batteries

In this study, a novel concept of multipoint anionic bridge (MAB) is proposed and proved, which utilizes anions with different sites to connect with the asymmetric solvation structure (ASS). Compared to usual solvation structures, this study utilizes the multifunctional groups of difluoro(oxalate)borate anion (ODFB-), which can connect with Li+. By tailoring the concentration, the anion serves as a bridge between different solvated structures. The electrolyte is investigated through in situ techniques and simulations to draw correlations between different solvation structures and reaction pathways. The proposed design demonstrates remarkable high-temperature performance on both the anode and cathode sides, enabling stable cycling of LCO||graphite (0.5 Ah, 1.0 C) pouch cell for over 200 cycles at 80 °C, and facilitating Li||MCMB and Li||LFP cells to deliver stable performance for 200 cycles at 100 °C. This work paves a way to develop high-performance electrolyte systems by designing and using new multipoint anions to construct ASSs.

Speaker: Mr Tianle Zheng (Technische Universität München)

1:45 PM P-021: Neutron Spin Echo Spectroscopy with the J-NSE "PHOENIX: recent scientific examples

The neutron spin echo spectrometer J-NSE "PHOENIX" is presented together with the most recent scientific examples. Mostly, the slow motion on molecular length scales of proteins in solution and polymers in the melt or in solution are measured. Recent publications in this area include experiments on asymmetric tubes in a polymer melt, on the effect of crowding in solutions of single chain nano-particles and on the determination of the cooperativity length in glass forming polymers. A different application of the NSE spectrometer are precision measurements of the echo phase shift during scattering at polarized isotopes ($^3$He, $^{129}$Xe, $^{131}$Xe) for the determination of the incoherent scattering lengths of the corresponding isotope.

Speaker: Olaf Holderer (Forschungszentrum Jülich GmbH, JCNS at MLZ)

1:45 PM P-078: New options on the polarized neutron single crystal diffractometer POLI at MLZ

Polarized neutron diffraction is a powerful tool for studying condensed matter physics and to probe the spin and orbital properties of unpaired electrons. POLI is a polarized neutron single crystal diffractometer built on the hot neutron source at MLZ. Currently three standard setups are implemented on POLI: 1) zero-field spherical neutron polarimetry using CRYOPAD; 2) polarized neutron diffraction in magnetic fields; 3) non-polarized diffraction under various conditions.
We recently implemented a new actively shielded asymmetric split-coil superconducting magnet with a maximal field of 8T. The magnet is designed to facilitate polarized neutron diffraction with low stray fields, a large opening (30 ° vertical) and a large sample space suitable for e.g., piezo goniometers, and pressure cells. We also built a compact-size solid-state supermirror bender polarizer optimized for short neutron wavelengths to provide high neutron polarization in the vicinity of the magnet. An in-situ SEOP polarizer and analyzer will be available soon which maintains high levels of neutron polarization and intensity over long periods of time. The SEOP polarizer are well shielded magnetically and can be used with the large magnet. Transferring the BIDIM26 area detector of size 26cm by 26cm from LLB to MLZ is in progress [3].

[1] V. Hutanu, J. Large-Scale Res. Facil. 1, A16 (2015).
[2] V. Hutanu et al., IEEE Trans. Magn. 58, no. 2, pp. 1-5, (2022).
[3] A. Gukasov et al., Physica B 397, 131 (2007).

Speakers: Jianhui Xu (RWTH Aachen University; JCNS), Dr Leonie Heinze (Jülich Centre for Neutron Science (JCNS))

1:45 PM P-006: NICOS: News and developments

NICOS, the Networked Instrument Control System, is the standard experiment control software developed and used by MLZ, and has been successfully implemented at other facilities like PSI and ESS. Its high degree of adaptability makes it feasible to provide a good user experience while keeping development effort manageable through the use of a strong shared core codebase.

In this poster, we give an overview of the current state of NICOS, the features under development, and an outlook of what users can expect for future beam times.

Speaker: Mr Georg Brandl (Forschungszentrum Jülich)

1:45 PM P-023: Non-insulated ReBCO coils for the confinement of Electron-Positron Pair Plasmas

The APEX Collaboration endeavours to magnetically confine electron-positron pair plasmas. The operational APEX-LD experiment is at the initial stage of electron plasma experiments, and concurrently, the EPOS Stellarator is in design phase. A key technology in both experiments is REBCO (Rare-earth Barium Copper Oxide) high-temperature superconductors.

REBCO presents itself as a promising technology for compact magnetic traps with moderate field strengths (0.5 - 2 T) due to its higher operating temperature (approximately 20 K) and superior performance within a magnetic field in contrast to low-temperature superconductors such as Nb3Sn and NbTi. The non-insulated coil design, devoid of turn-to-turn insulation between the ReBCO windings, offers enhanced stability and robustness, and provides passive quench protection.

For EPOS, the non-planar coils require careful optimization of the winding pack orientation to prevent damage to the ReBCO tape. We've optimized, constructed and tested several test coils to validate the strain optimization process. Furthermore, we've built a number of compact, double pancake coils that not only emulate the winding pack conditions of the EPOS stellarator but also serve as a potential test platform for the injection of Rydberg positronium into magnetic fields.

Speaker: Paul Huslage

1:45 PM P-031: NREX and TRISP upgrades

TRISP is currently relocated to the guide hall east, and the length of the polarizing neutron guide increases from 10 m to 30 m. Transmission losses of this longer guide are minimized in the thermal spectrum range (1-4 Å) by a ballistic guide with parabolic and elliptic sections at the input and output, each 13 m long. The straight transmission polarizer in the center (4 m length) shows very good performance due to the low beam divergence at the exit of the first parabolic section. This guide design will provide a similar flux at TRISP as before, even with a slight increase at λ < 2 Å.

At NREX we installed new sample environment to investigate thin film samples in H2 or D2 atmospheres: A gas handling system with remote pressure control (0-1bar), a sample chamber with both neutron and x-ray windows, and a He3 cryostat (0.5 - 300K) also with neutron and x-ray windows for simultaneous reflectometry measurements. New sample holders with spring loaded electrical contacts permit simultaneous neutron and x-ray reflectometry, without the need to wire-bond the samples. The contact arrangement is of van-der-Pauw type (4 contacts on a square) connected to a relais matrix, such that the current flow and voltage measurement can be freely assigned, either parallel or perpendicular to the external H field, or in crossed geometry for Hall measurements. The voltage is measured by a sensitive lock-in amplifier, and thus very low excitation currents avoiding sample heating are possible.

Speaker: Thomas Keller (Max Planck Institute FKF)

1:45 PM P-001: Optimization Methods for Material Science

Optimization Methods for Material Science

The Setup for LOw-energy Positron Experiments (SLOPE) at the MLL creates a state-of-the-art monoenergetic positron beam, tailored to the needs of (near-) surface positron annihilation spectroscopy. [1]
The beam is guided by a series of magnetic coils and electrostatic lenses onto the sample, where the positrons annihilate with electrons inside the material. The Doppler broadening of the 511 keV line then reveals the local electronic structure.

The electromagnetic guidance system needs to be precisely optimized in order to focus the beam onto the sample. We showcase an implementation of Bayesian Optimization, which outperforms more conventional algorithms (e.g. downhill simplex), offering greater robustness and improved efficiency for the Beam optimization.

Additionally, we show that deep learning techniques can greatly reduce the number of measurements taken during beam width and position optimizations, while maintaining good accuracy. This results in faster optimization compared with traditional least squares fitting.

[1] L. Mathes, M. Suhr, V. V. Burwitz, D. R. Russell, S. Vohburger, and C. Hugenschmidt, "Surface and near-surface positron annihilation spectroscopy at very low positron energy," arXiv preprint, arXiv:2409.07952, Sep. 2024.

Speaker: Saad Alam

1:45 PM P-005: Origins of polysaccharide conformation and viscoelasticity in miscible heterogeneous solvent

Polysaccharide polymers constitute the fundamental building blocks of life and display a diverse set of conformations; the origins of which need further understanding. Utilising a model high molecular weight, high Trouton ratio bottlebrush-like 'pectin' polysaccharide extracted from okra (Abelmoschus esculentus) mucilage, we combine theoretical (molecular dynamics simulation) and experimental (rheology, calorimetry, and small-angle scattering) investigations, to unveil the underlying microscopic hydrodynamic origins of polysaccharide conformation. In miscible heterogenous solvents of water and glycerol (cosolvent), we observe that the polysaccharide chain undergoes a non-monotonic conformational transition from flexible-to-extended-to-collapsed configurations, resulting in pronounced viscoelastic responses. Molecularly structured water molecules within ca. 0.40 nm of the chain surface is observed with an increase of glycerol in the solvent composition. We postulate that this increased water elicits an entropically unfavourable dynamic solvent heterogeneity, which is ameliorated by swelling and collapse of polysaccharide chains. Together with elastic fixed window scans on the thermal backscattering spectrometer IN13 (Institute Laue-Langevin, France), we demonstrate water’s association to pectin chains. Our results offer new insights applicable to fundamental biopolymer science and biomaterial engineering, previously inaccessible through mean-field assumptions.

Speaker: Dr Pallab Kumar Borah (Technical University of Munich)

1:45 PM P-050: OSCARS: Taking science research to the next level

Open Science Clusters’ Action for Research and Society (OSCARS) is a EU-funded project that will bring your research data to new audiences and target new use-cases. The FAIR (Findable, Accessible, Interoperable and Reusable) principles facilitate research data to be used in new and novel ways, with increased citations acknowledging the original researchers and facilities that provided that data.

OSCARS covers a broad range of science activities, including Humanities and Social Sciences, Life Sciences, Environmental Sciences, Astronomy, and Neutron and Photon (PaN) Science. This allows adoption and tailoring of existing software and services to match PaN needs.

OSCARS builds on the outcome of the European Open-Science Cloud to support open science by four main approaches.
(1) Establishing community-based competence centres will enhance the communication between the science clusters.
(2) Creating a catalogue of existing services, data hubs and analysis platforms of varying maturity and identifying those with promising composability prospects to provide broader support for scientific investigation.
(3) Building connections towards other EOSC projects, task forces and related work to ensure benefits from existing work, to align OSCARS activity with effort elsewhere, and to increase the uptake of OSCARS outcomes.
(4) Overseeing a funding programme accepting a wide range of proposals that target open science and the FAIR data environment.

Speaker: Melanie Nentwich (DGK)

1:45 PM P-044: PALS of Hot-Rolled and Subsequently T4-Treated AlCu4Mg0.3Ag0.7

Positron Annihilation Lifetime Spectroscopy (PALS) is a unique tool for studying precipitation hardening in Al alloys, utilizing the tendency of positrons to get trapped in Cu clusters/precipitates.
Alloying AlCu with Ag has been shown to leverage the formation of the so-called Ω-phase, known for its particularly high strength and thermal stability.
After discussing optimal Al-alloy surface treatments for positron annihilation spectroscopy, we present PALS measurements of AlCu4Mg0.3Ag0.7 containing Ω-phase precipitation after hot-rolling and subsequent T4-treatment.
Our measurements showcase the high thermal stability of the Ω-phase and can be used to optimize process parameters of the strength hardening and the temperature treatment.
All data presented have been recorded at the SLOPE facility at TUM [1] and the ELBE facility at HZDR [2].

[1] L. Mathes, M. Suhr, V. V. Burwitz, D. R. Russell, S. Vohburger, and C. Hugenschmidt, "Surface and near-surface positron annihilation spectroscopy at very low positron energy," arXiv preprint, arXiv:2409.07952, Sep. 2024.

[2] A. Wagner, M. Butterling, M.O. Liedke, K. Protzger, R. Krause-Rehberg, "Positron annihilation lifetime and Doppler broadening spectroscopy at the ELBE facility," AIP Conference Proceedings 1970, 2018.

Speaker: Lucian Mathes

1:45 PM P-003: PANDA - Cold TAS going thermal

PANDA is the cold three-axis spectrometer (TAS) at MLZ, successfully serving scientists from around the world since 2005. In preparation for continued user operations, the instrument has undergone comprehensive maintenance and upgrades. It is now equipped with a new PG-002 monochromator, a versatile sample table capable of supporting cryomagnets, and an ADR cryostat operating from room temperature down to 300 mK (and 100 mK in single-shot mode), all within a single setup.

Due to the thermal overlap in the incoming spectrum, PANDA will be ready for experiments immediately upon the restart of user operations. To further optimize performance, the Cu-111 and bent Si-111 monochromators can be used to extend the energy range or minimize second-order contamination, respectively. Simulations indicate that the incoming flux at the sample position will reach (0.5–1) × 10⁸ n/cm²/s, enabling standard PG-filter experiments for energy transfers up to $\Delta$E $\approx$ 35 meV, as well as high-resolution Be-filter experiments for $\Delta$E $\approx$ 15 meV, though with intensities reduced by a factor of ~2.5 compared to standard reactor operation.

A key aspect of PANDA's restart will be the commissioning of the BAMBUS multiplexing option. Although it is designed for a cold spectrum, immediate tests, background characterization, and software validation are needed to enable its use for Be-filter experiments on, e.g., strongly scattering samples as soon as possible.

Speaker: Dr Lukas Beddrich (Jülich Centre for Neutron Science (JCNS) at MLZ, Forschungszentrum Jülich GmbH, Garching, Germany)

1:45 PM P-024: Physics-informed input representations for SANS patterns classification

Small Angle Neutron Scattering (SANS) is a vital technique for probing the structural properties of materials at the nanoscale. This makes it indispensable for studying nanometer-sized physical systems. Traditionally, SANS data analysis relies on mathematical models, but the advent of Machine Learning has offered new tools for data analysis. Recent work (Robledo, et al., 2024) shows that Convolutional Neural Networks (CNNs) can predict material structure from 2D SANS images with high accuracy across diverse datasets.

However, the computational cost and extensive data requirements of deep learning models pose challenges, particularly when dealing with smaller datasets. To address this, we propose a physics-informed input representation utilizing the Fourier transform in polar coordinates, which aligns naturally with the circular symmetry often observed in isotropic materials.

Our results, based on synthetic SANS patterns, show that this input representation can be effectively classified with a simpler shallow neural network, achieving performance comparable to deep CNNs. Moreover, when applied to CNNs, the physics-informed input encoding further enhances model accuracy. We evaluate the network's performance with real experimental data, exploring the robustness of our method.

In conclusion, we develop a more efficient data analysis procedure that incorporates domain-specific knowledge and facilitates faster and more robust SANS model recommendations for smaller datasets.

Speaker: Stefan Häusler

1:45 PM P-051: Plans to characterize the NEPOMUC beam with a Retarding Field Analyzer

The retarding field analyzer (RFA) is capable of measuring the intensity, spatial spread, as well as parallel and perpendicular energy distributions for the different positron beams provided by NEPOMUC.

The last RFA measurements were conducted nearly a decade ago[1], making new measurements essential, particularly in light of the recent modernizations at NEPOMUC. Moreover, the installation of a buffer-gas trap (BGT) system into the NEPOMUC beamline is planned, with the objective of providing high-intensity positron pulses with significantly narrower energy spreads to the experiments. It is therefore also necessary to characterize the output of the BGT, including the confirmation of its lack of adverse effects on the standard NEPOMUC beam, such as non-adiabatic transport.

Here, we present the preliminary plans for the upgrade of the RFA since its last use, as well as single-particle simulations of beam guiding and ray-tracing-based signal estimates.

[1] https://doi.org/10.1016/j.nima.2016.04.093

Speaker: Stefan Nißl (IPP)

1:45 PM P-080: Poly(acrylic acid) locally enriched in slurry enhances the electrochemical performance of the SiOx lithium-ion battery anode

Silicon oxide (SiOx) is recognized as a promising anode material for high-energy lithium-ion batteries (LIBs) due to its abundant reserves, facile synthesis, and high theoretical capacity. However, the practical use of the SiOx anode is severely hampered due to its poor cycling stability caused by a large volume change upon lithiation/delithiation. The waterborne poly(acrylic acid) (PAA) binder has been regarded as one of the most promising binders for SiOx-based anodes. In this work, a new concept is developed using locally an enriched PAA binder to enhance the structural stability of the electrode, the adhesion force between the electrode and the current collector, and the dispersion of carbon black within the electrode. By simply replacing water with an organic solvent (for example, N, N'-dimethyl formamide, DMF), the PAA binder is enriched locally in DMF because the PAA chains collapse in the DMF solution, leading to an increased functional group density. Improved electrochemical performance in terms of capacity retention and rate capacity is achieved by the locally enriched PAA binder in both half-cell and full-cell configurations. This work establishes a new concept practically feasible for applications of the alloying-based lithium-ion battery anode.

Speaker: Ming Yang (Technische Universität München)

1:45 PM P-058: QtiSAS: SA(N)S data reduction and analysis platform.

QTISAS is a versatile software package designed for the analysis and modeling of small-angle scattering (SAS) data, specifically for neutron and X-ray scattering experiments. Built with a user-friendly graphical interface and advanced computational algorithms, QTISAS facilitates the interpretation of scattering data from diverse sample types, including complex fluids, polymers, biological macromolecules, and nanomaterials. The software supports various modeling approaches, such as form factor fitting, structure factor analysis, enabling precise determination of particle sizes, shapes, and interparticle interactions. QTISAS integrates data reduction, visualization, and fitting processes within a single platform, streamlining workflows for both beginners and experienced researchers. Key features include support for multi-contrast datasets, batch processing, and automated fitting routines, making QTISAS an essential tool for researchers seeking reliable and high-throughput analysis of scattering data. The software is constantly updated to incorporate the latest scientific developments, ensuring compatibility with modern scattering techniques and experimental setups.

Speaker: Dr Vitaliy Pipich (Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ Forschungszentrum Jülich GmbH)

1:45 PM P-043: REFSANS: The horizontal time-of-flight reflectometer with GISANS option at the Heinz Maier-Leibnitz Zentrum

REFSANS is the horizontal TOF reflectometer at the MLZ, designed for reflectometry and GISANS studies of any interface, as well as to give simultaneous access to a range of Qz values.
Wavelength resolution may be tuned from 1.0 % up to 10%. The optics comprises neutron guide elements with different channels and special apertures to provide slit smeared or point focused beams for NR or GISANS measurements.
The investigation of kinetic processes is possible thanks to the possibility to embrace a Qz-range with a single instrumental setting. Time resolution can be pushed down to 30 s with data recorded in event-mode: this feature makes possible to perform various time re-binnings in order to tune the resolution/ intensity trade-off after the experiment.
Taking advantage of the long reactor shutdown, extensive simulations has been performed to find solutions that could increase the performance of the instrument and the flux at the sample position. It has been verified that with a modified design of the instrument geometry and with a new geometry of the radial collimators it would be possible to increase the flux on the sample up to a factor ~ 4 for NR and ~ 8 for GISANS measurements, for sample of typical sizes (50·80 mm²). The new design makes also possible to investigate small interfaces (30·30 mm²) with a gain factor of ~ 3 in intensity, opening new options for the experimental analysis of interfaces.

Speaker: Gaetano Mangiapia

1:45 PM P-067: Relocation of the cold triple axis spectrometer FLEXX to MLZ, Munich: Larmor diffraction and inelastic scattering

The cold triple-axis spectrometer (TAS) FLEXX at HZB is a well-designed and upgraded instrument [1-4]. There is a strong wish that this excellent instrument should be preserved for the community. One attractive gap in the present instrumentation suite of MLZ, is the Larmor-diffraction technique [5-6] (LD) and, as a natural extension, cold neutron resonant spin echo (NRSE). TAS comes at no extra cost, as it is the main backbone of such an instrument.
The instrument will be placed on a cold neutron guide. Further, new developments are under way to allow for application of magnetic fields at the sample, hitherto not possible [7-9]. This opens up new vistas in the exploration of materials. A last attractive option is the possibility to combine high magnetic fields together with cold TAS.

[1] M. Skoulatos et al., NIMA 647, 100 (2011).
[2] M.D. Le et al., Nucl. Instr. Meth. Phys. Res. A 729, 220 (2013).
[3] F. Groitl et al., Rev. Sci. Instrum. 86 025110 (2015).
[4] K. Habicht et al., EPJ Web of Conferences 83, 03007 (2015).
[5] M.T. Rekveldt, Jour. Appl. Phys. 84, 31 (1998).
[6] M.T. Rekveldt et al., Europhys. Lett. 54, 342 (2001).
[7] Neutron Spin Echo - Proceedings of a Laue-Langevin Institut Workshop, Grenoble, Springer- Verlag, Ed:
F. Mezei (1980).
[8] M.T Rekveldt et al., Jour. Appl. Cryst. 47, 436 (2014).
[9] K. Habicht, “Neutron-Resonance Spin-Echo Spectroscopy: A High Resolution Look at Dispersive Excita-
tions”, Habilitation, University of Potsdam (2016).

Speaker: Markos Skoulatos (TUM)

1:45 PM P-016: Resolution and sensitivity improvements in the detection of positrons using CMOS technology.

In 2023 we published an innovative positron detection technique based on direct detection using CMOS imaging sensors. That work did set the resolution record for real-time detectors but possibly not for non-realtime devices. We present our latest improvements on the result, which yield the highest spatial resolution ever achieved while detecting positrons.

Speaker: Francesco Guatieri (Università degli Studi di Trento)

1:45 PM P-082: Revealing the effect of solvent additive selectivity on formation kinetics in printed active layers for organic solar cells

Solvent additives have received tremendous attention in organic solar cells as an effective way to optimize morphology and phase separation. However, most research primarily focuses on solvent additives with superior solvation for non-fullerene acceptors (NFA) over polymer donors, such as the 1-chloronaphthalen (1-CN) and 1, 8-diiodooctane (1,8-DIO). Few researches are related to solvent additives characterized by better solubility for polymer donors than NFA. Furthermore, the impact of solvent additives is mainly investigated through spin coating rather than slot-die coating, which exhibits distinct kinetics in the film formation. Hence, the influence of solvent additive selectivity on the kinetics of the active layer formation in printed active layers remains unknown. In this study, we use PBDB-T-2F as the donor and BTPC3-4F as the acceptor and introduce two distinct solvent additives, one with superior solubility for PBDB-T-2F compared to BTP-C3-4F, and the other one with inferior solubility for PBDB-T-2F. The drying process of the slot-die coated active layers with different solvent additives is studied with in situ UV-vis absorption spectra and in situ grazing incidence wide angle X-Ray scattering (GIWAXS).

Speaker: Jinsheng Zhang (TUM)

1:45 PM P-081: SECoP: The Sample Enviroment Communication Protocol

The integration of sample environment (SE) equipment in a beam line experiment is a complex challenge both in the physical world and in the digital world. Different experiment control software offer different interfaces for the connection of SE equipment. Therefore, it is time-consuming to integrate new SE or to share SE equipment between facilities.

To tackle this problem, the International Society for Sample Environment (ISSE) developed the Sample Environment Communication Protocol (SECoP) to standardize the communication between instrument control software and SE equipment (see [1] and references therein). SECoP offers, on the one hand, a generalized way to control SE equipment. On the other hand, SECoP holds the possibility to transport SE metadata in a well-defined way.

Using SECoP as a common standard for controlling SE equipment and generating SE metadata will save resources and intrinsically give the opportunity to supply standardized and FAIR data compliant SE metadata. It will also supply a well-defined interface for user-provided SE equipment, for equipment shared by different research facilities and for industry.

Speaker: Alexander Zaft (JCNS-4)

1:45 PM P-038: Silicon detector for neutron beta decay measurements with PERC

The PERC facility is currently under construction at the FRM II in Garching, Germany. It will serve as an intense and clean source of electrons and protons from neutron beta decay for precision studies. It aims to improve the measurements of the properties of weak interaction by one order of magnitude and to search for new physics via new effective couplings.
PERC's central component is a 12 m long superconducting magnet system that has been delivered. It hosts an 8 m long decay region in a uniform field. An additional high-field region selects the phase space of electrons and protons, which can reach the downstream detector to minimize systematic uncertainties.
The downstream detector and the two upstream backscattering detectors will initially be scintillation detectors with (silicon) photomultiplier readout. In a later upgrade, the downstream detector will be replaced by a pixelated silicon PIN-detector. This new detector is 2mm thick. The entrance window consists of a 100nm thin p+ doped layer with a 300nm thin aluminium grid on top and the readout side is 500nm of pixelated n+ doping.
We are presenting the first results of its characterization.

Speaker: Manuel Lebert (Technical University Munich)

1:45 PM P-061: Simultaneously fitting molecular dynamics simulations to neutron and X-ray diffraction and spectroscopy data with a bayesian approach

Neutron and X-ray scattering experiments provide valuable insights into the nanoscopic properties of matter, a scale that is also accessible through Molecular Dynamics (MD) simulations. If the simulations reproduce the experiments, they can give greater insight into the material properties on the nanoscopic scale than traditional data analysis methods. However, existing MD forcefields are primarily optimized to reproduce macroscopic quantities.
In our work we establish a connection between published experimental data from neutron and X-ray experiments, specifically focusing on diffuse scattering and quasielastic neutron scattering, and MD simulations.
We integrate tools for MD simulation (LAMMPS) and scattering curve computation (Sassena) in a custom built Bayesian framework that employs a Markov Chain Monte Carlo approach to sample a parameter space. Our approach explores a broad range within the parameter space, enhancing the likelihood of finding the global minimum of forcefield parameters. This approach is highly versatile and can be adapted to different systems. We compare this approach to a simple brute force method of finding an adequate fit. In this work, we utilize liquid water as a proof of concept.

Speaker: Mrs Veronika Reich (GEMS at MLZ, Helmholtz-Zentrum Hereon)

1:45 PM P-060: Single crystal diffraction data reduction with OpenHKL

Data reduction is a crucial prerequisite to data analysis in neutron scattering experiments; in the case of single crystal diffraction, it involves the reduction of a set of images at fixed sample rotation increments to a set of Miller indices and detector coordinates. However, the available mature software solutions for this problem are either legacy codes, converted from X-ray diffraction, or are closed-source.

OpenHKL is a standalone program, currently under development, with a modern graphical user interface that facilitates the data reduction workflow. It is written in C++ for excellent speed, is open-source and well documented, natively handles neutron diffraction experiments with different detector geometries, and has a convenient Python scripting interface. It has been successful in the reduction of macromolecular crystallography data from the BioDiff instrument, and is being extended to work with other instruments.

This poster will present the latest updates in the development of OpenHKL.

Speaker: Zamaan Raza (Forschungszentrum Jülich)

1:45 PM P-027: Sputter-Deposited TiOx Thin Film as a Buried Interface Modification Layer for Efficient and Stable Perovskite Solar Cells

It is crucial to suppress the non-radiation recombination in the hole-blocking layer (HBL) and at the interface between the HBL and active layer for performance improvement. Herein, TiOx layers are deposited onto a SnO2 layer via sputter deposition at room temperature, forming a bilayer HBL. The structure evolution of TiOx during sputter deposition is investigated via in situ grazing-incidence small-angle X-ray scattering. After sputter deposition of TiOx with a suitable thickness on the SnO2 layer, the bilayer HBL shows a suitable transmittance, smoother surface roughness, and fewer surface defects, thus resulting in lower trap-assisted recombination at the interface between the HBL and the active layer. With this SnO2/TiOx functional bilayer, the perovskite solar cells exhibit higher power conversion efficiencies than the unmodified SnO2 monolayer devices.

Speaker: Xiongzhuo Jiang (Physics Department, TU Munich)

1:45 PM P-032: Status Report of the MEPHISTO Beamline

The author will present the actual status of the work at the MEPHISTO beamline. The installation of the neutron guide shielding in the reactor building and in the intermediate structure are advancing. The cooling plant is progressing with the construction of the compressor tower.

Speaker: Jens Klenke (FRM II)

1:45 PM P-025: Structural analysis of cation mixing in NCA-type battery cathodes

Lithium-ion batteries with high-nickel content Li$_{x}$Ni$_{0.8}$Co$_{0.15}$Al$_{0.05}$O$_{2}$ (NCA) cathodes and high-performance graphite are emerging as key components in electric vehicles, offering high energy and power densities at low costs [1, 2]. However, the efficiency of these batteries is hindered by the diffusivity of Li-ions, particularly in nickel-rich cathodes where Li$^{+}$/Ni$^{2+}$ cation mixing can block the 2D diffusion pathways, reducing the cell capacity and structural stability [3]. This study presents a systematic ex situ neutron powder diffraction analysis of NCA cathodes from real 18650-type cells, showing decreasing lithium concentration with higher charge states and the absence of cation mixing within the NCA structure during the electrochemical cycle, as revealed by Rietveld refinement.
[1] Zhao, G., et al., iScience, 25(2), 2022 (DOI: 10.1016/j.isci.2022.103744).
[2] Purwanto, A., et al., Materials Research Express, 5(12), 2018 (DOI: 10.1088/2053-1591/aae167)
[3] Dolotko, O., et al., Journal of Power Sources, 255, 2014 (DOI: 10.1016/j.jpowsour.2014.01.010)

Speaker: Tobias Hölderle

1:45 PM P-012: Structural studies of halide-based superionic Lithium conductors

The urgent need for sustainable energy solutions to address climate change and the increasing demand for high energy and power density have positioned solid-state batteries as a key area of research. Lithium metal chlorides (Li₃MCl₆) have emerged as promising candidates for next-generation batteries due to their high ionic conductivity, thermodynamic stability, and favorable mechanical properties. In this study, we investigated Li₃MCl₆ compounds with M = Dy, Ho, Tb, and Tm through X-ray diffraction (XRD), confirming that all samples crystallize in the space group P3̅m1, though exhibiting poor crystallinity and high disorder without post-synthesis annealing. Additionally, electrochemical impedance spectroscopy (EIS) was employed to evaluate their ionic conductivity, offering further insights into their potential for solid-state battery applications.

Speaker: Francesco Falsina

1:45 PM P-037: Suppressed degradation process of PBDB-TF-T1:BTP-4F-12 solar cells with solid additive EH-P

Solid additives have garnered significant attention due to their numerous advantages over liquid additives, which could help to enhance the device performance and stability of organic solar cells. In this study, we explore the potential of the polymer EH-P as a solid additive in green-solvent-based PBDB-TF-T1:BTP-4F-12 solar cells. Even tiny amounts of EH-P doping significantly improve device performance. For the reference solar cell without any additive, we found that cell device degradation is not caused by chemical reoxidation but by changes in crystallinity and microstructure evolution during aging in air under illumination. Operando GIWAXS and GISAXS are used to investigate this structure evolution. We discovered a three-stage degradation process for the reference cell. In general, the d spacing and crystallite coherence length decrease while the domain sizes increase, which causes the loss of JSC and FF. Furthermore, a decomposed component is detected in GIWAXS and GISAXS, which corresponds to the loss of VOC. EH-P doping effectively suppresses the evolution of crystallinity and domain sizes, enhancing device stability under illumination in the air. The detailed evolution of the donor and acceptor is further analyzed via separated-fitting the π-π stacking signal, and EH-P is found to be more effective for the acceptor. This demonstrates the promising potential of EH-P doping in solar cell technology.

Speaker: ZERUI LI (TUM)

1:45 PM P-035: Temperature-dependent neutron diffraction and magnetic studies on magnesium ferrite (MgFe2O4) powder prepared via Sol-Gel auto-combustion method using DL-alanine fuel

The present work investigates crystallographic and magnetic structures of post-annealed magnesium ferrite (MgFe2O4) powder using Neutron diffraction within a temperature range from 10 K to 300 K. The obtained crystallite and domain size variations show a robust correlation with the changes in magnetic properties, as determined by temperature-dependent magnetic measurements. Further, the study delves into the magnetic behavior under zero-field cooling (ZFC) and field-cooling (FC) conditions through the vibrating sample magnetometer (VSM), confirming the ferrimagnetic nature of MgFe2O4 powder. The decrease in Magnetic domain size with decreasing temperature and the negligible variation in crystallite size with a decrease in measurement temperature is thoroughly examined. This obtained decrease in domain size with decreasing temperature is attributed to the increase in the coercive field. Furthermore, the magnetic moments for one MgFe2O4 molecule have been estimated through the Rietveld refinement of neutron diffraction patterns, and the magnetic moment calculated from saturation magnetization shows good agreement. The Electron Spin Resonance (ESR) technique is employed to investigate the magnetic behavior of MgFe2O4 within a wide temperature range from 90 K to 300 K, focusing on dipolar and super-exchange interactions. The ESR spectra linewidth increases from 1225 Oe to 1870 Oe as the temperature decreases from 300 K to 90 K, indicating the enhancement of magnetic interactions.

Speaker: Dr Sudhanshu Kumar (Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM-II), Technische Universität München (TUM) and Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstraße 1, D–85748, Garching bei München, Germany.)

1:45 PM P-074: Temperature-resolved Crystal Structure of Ethylene Carbonate

For more than three decades, lithium-ion batteries (LIB) have been widely used as power sources for portable electronics and are of interest for electric vehicles and network applications (large-scale electricity storage). While there have been significant changes from the initial design of the LIB, the main solvents constituting the liquid electrolyte, responsible for the charge transfer between the electrodes, remained mainly unchanged [1]. An important class of solvents used in liquid electrolytes are linear and cyclic carbonates, because of the combination of physical/chemical properties in a mixture with two or more solvents with a lithium salt and additives [1]. Ethylene carbonate (EC), with its high dielectric constant [1] and ability to provide the protective SEI layer, is present in almost all commercial batteries, mixed with other solvents due to its high melting point [2].
After the determination of the crystal structure of EC from single crystals [3], this contribution presents room temperature data obtained by Neutron Powder Diffraction at SPODI (FRM II), temperature-dependent Neutron Powder Diffraction data from ECHIDNA (ANSTO) and Total Scattering and temperature dependent Powder X-Ray Diffraction data measured at P02.1 (DESY), showing the structural evolution from 3 K up to its melting point.
[1] G. Eshetu et al., Phys. Chem. Chem. Phys. 15, 9145-9155 (2013)
[2] J.-M. Tarascon & M. Armand, Nature 414, 359-367 (2001)
[3] C.J. Brown, Acta Cryst. 7, 92-96, (1954)

Speaker: Lea Westphal (TUM/MLZ)

1:45 PM P-014: Texture of Hot-Compressed Metastable β-Titanium Alloy Ti5321 Studied by Neutron Diffraction

The textures of the β- and α-phases of the metastable β-titanium alloy Ti5321 after hot deformation were investigated by neutron diffraction. A hot-rolled bar was solutionized in the β-phase field and then hot compressed above and below the β-transus temperature. The initial texture after full recrystallization and grain growth in the β-phase field exhibits a weak cube component {001}<100> and minor {112}<110> and {111}<110> components. After hot compression, a <100> fiber texture is observed, increasing in intensity with compression temperature. Below the β-transus temperature, dynamic recrystallization of the β-phase and dynamic spheroidization of the α-phase interact strongly. The texture of the α-phase is a <11–20> fiber texture, increasing in intensity with decreasing compression temperature. The mechanisms of texture formation during hot compression are discussed.

Speaker: Dr Weimin Gan (Helmholtz-Zentrum Hereon)

1:45 PM P-053: The Macromolecular Neutron Single Crystal Diffractometer BIODIFF for Proteins at the Heinz Maier-Leibnitz Zentrum MLZ

Neutron single crystal diffraction provides an experimental method for the direct location of hydrogen and deuterium atoms in biological macromolecules. At the FRM II neutron source the neutron single crystal diffractometer BIODIFF, a joint project of the Forschungszentrum Jülich and the FRM II, is dedicated to the structure determination of enzymes. Typical scientific questions address the determination of protonation states of amino acid side chains, the orientation of individual water molecules and the characterization of the hydrogen bonding network between the enzyme active center and an inhibitor or substrate. This knowledge is often crucial towards understanding the specific function and behavior of an enzyme. BIODIFF is designed as a monochromatic diffractometer and is able to operate in the wavelength range of 2.4 Å to about 5.6 Å. This allows to adapt the wavelength to the size of the unit cell of the sample crystal. Data collection at cryogenic temperatures is possible, allowing studies of cryo-trapped enzymatic intermediates. Recently a hexapod has been installed at BIODIFF which allows an online collimator alignment. Some recent examples will be presented to illustrate the potential of neutron macromolecular crystallography. In addition, a potential detector upgrade will be presented.

Speaker: Dr Andreas Ostermann (Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München)

1:45 PM P-029: The Resonant Spin-Echo Spectrometer RESEDA

The MIEZE (Modulation of Intensity with Zero Effort) technique is a high-resolution spin-echo time-of-flight technique, for which all spin manipulations are carried out upstream of the sample, in contrast to classical neutron spin-echo spectroscopy. Perhaps most intriguingly, this technique is robust against depolarizing conditions at the sample position.
Therefore, magnetic, or strongly incoherently scattering samples can easily be measured without loss of signal.
The spectrometer RESEDA is being further optimized for measurements in a small angle geometry. We present the current status of the newly installed superconducting solenoids as part of the RF flippers to significantly extend the dynamic range as well as the development and installation of a new detector on a translation stage within a new larger SANS-type vacuum vessel for flexibility with angular coverage and resolution.

Speaker: Johanna Jochum

1:45 PM P-075: TOFTOF – actual status and renewal concept

The cold neutron time-of-flight chopper spectrometer TOFTOF is versatile to address large parts of the relevant momentum and energy transfer range, with a tunable energy resolution, and it has a strong user base in the disordered materials community (materials sciences, soft matter, life sciences, magnetic materials). Here we want to discuss the actual status of TOFTOF and the expected influence of the broken cold source of the FRM II on TOFTOF.
The instrument is in operation since 2005, and some critical components (chopper system, detector electronics) are likely to ultimately fail, with no possibility for repair or spare part supply. At the same time, advances in neutron optics technology and the use of position sensitive detectors will be made use of to further enhance the attractiveness of the instrument to an even broader user base. Both points shows that a rebuild is needed to ensure ongoing TOFTOF user operation with a state of the art instrument. Here we want to discuss our plans for the rebuild of the Instrument TOFTOF.

Speaker: Marcell Wolf (TUM)

1:45 PM P-068: TOPAS: time-of-flight spectrometer with polarization analysis

We present the time-of-flight spectrometer TOPAS being assembled in the neutron guide hall east. It is optimized for mapping excitations in large areas of the reciprocal space utilizing thermal neutrons. The chopper system is designed to deliver neutrons in the thermal energy range, which allows for energy transfers up to 50 meV on the neutron energy loss side, and resolution around 5% of the incoming neutrons energy. The instrument includes polarization analysis based on a large He$^3$ cell in the primary beam and another He$^3$ cell embedded in the Magic-PASTIS system as the analyzer.

The contribution explains in more detail the design ideas, recent developments, technical solutions and parameters, as well as plans for future measurements at the instrument.

Speaker: Michal Stekiel (Juelich Centre for Neutron Science)

1:45 PM P-026: Towards F.A.I.R. data: Research data management at JCNS

The Jülich Center for Neutron Science (JCNS) institutes conduct cutting-edge experiments leveraging various techniques. These experiments generate diverse and complex datasets, varying significantly in type, format, and volume due to the range of instruments used both within and outside the institutes. The heterogeneous nature of the data—from raw measurements to processed results—creates challenges in ensuring data are properly organized, stored, and accessible for future use.

To address these challenges, we present the initial plan to the development of the JCNS-Jülich Data platform, a (meta)data management system designed to support stakeholders across the research lifecycle—from experiment preparation to data ingestion, analysis, curation, and publication. Aligned with the principles of F.A.I.R. data (Findability, Accessibility, Interoperability, and Reusability), the platform provides a structured and standardized approach to managing experimental data. Additionally, it incorporates guidelines from several neutron science initiatives, such as DAPHNE4NFDI and ExPaNDS, as well as the Helmholtz Metadata Collaboration (HMC), ensuring compliance with community standards and fostering interoperability with broader scientific efforts. This development represents steps towards the digital transformation at JCNS, enhancing the F.A.I.R.-ness of data.

Speaker: Ahmad Zainul Ihsan (JCNS-1, Forschungszentrum Jülich GmbH)

1:45 PM P-072: Towards FAIR data at MLZ

DAPHNE4NFDI is a consortium within the Nationale Forschungsdaten Infrastuktur (NFDI) in Germany, dedicated to the development of data management tools and best practices for research data from Photon and Neutron (PaN) sources. The consortium's tasks include collecting and documenting data and metadata during the experiment with the aim to develop the FAIRness (Findability, Accessibility, Interoperability, and Reuse) of data. Here we present draft recommendations for the captured, aggregated and stored metadata of experiments at PaN large scale infrastructure facilities, as well as an electronic lab book that we are developing and setting up for MLZ users.

Speaker: Yuliia Tymoshenko (IQMT KIT)

1:45 PM P-022: Towards the development of polarization analysis with high energy resolution for SPHERES

Neutron polarization analysis provides profound additions of knowledge to the field of soft condensed matter research. The ability to separate the coherent and incoherent scattering contributions gives information on spatial correlations and collective motion, and information from single particles, respectively.
In this study, we focus on upgrading the SPHERES (SPectrometer for High Energy RESolution) backscattering instrument at JCNS [1,2] to meet the demands for high energy resolution and polarization analysis. Because of geometry constraints the polarization analyzer would need to be located between the sample and the Si111 analyzers. Based on this design, we explore transmission wide angle polarizer supermirror analyzer option through Monte-Carlo simulations [3]. At this conference, we will present our work towards performing polarization analysis with the high-resolution capabilities at the SPHERES instrument.

[1] J.Wuttke, Rev. Sci. Instrum. 83, 075109 (2012)
[2] J.Wuttke, Rev. Sci. Instrum. 84, 115108 (2013)
[3] P. Böni, Nucl. Instrum. Methods Phys. Res. Sect. A 966, 163858 (2020)

Speaker: Chuyi Huang (Jülich Centre for Neutron Science)

1:45 PM P-085: Towards transferable force fields for simulating biological membranes

Classical molecular dynamics (MD) simulations are often used to provide detailed insights of model cell membranes difficult to access directly via experimental means. This can either be done directly or by aiding in the interpretation of experimental data (incl. those obtained from neutron scattering)
The utility of MD simulations, however, depends on the accuracy and transferability of the underlying force field description (e.g., parameters, functional forms etc.). Currently available lipid force fields are unreliable for modelling more realistic and complex membrane systems and their interaction with other biologically relevant molecules.
In this study, I take a robust bottom-up approach to re-examine and re-parameterize force field terms used in small molecule analogues of common components in different lipid species by comparing to their experimentally derived properties (e.g., pure liquid and solvation properties). Refinements for the force field descriptions of small molecules, including hydrocarbons and esters, are proposed. The effect of the refined parameters in lipid bilayer systems is also assessed. A key element of this work is minimizing confounding variables that can mislead parameterization efforts. This was done by ensuring that the calculation of observables is performed in a regime that reduce their sensitivities to the precise choice of simulation settings, and explicitly considering the correlations between different force field parameters.

Speaker: zihan Zhou (MLZ)

1:45 PM P-040: Tracking degradation of non-fullerene organic solar cells under dynamic environmental conditions

Organic solar cells (OSCs) can be flexible, lightweight, and low-cost, but one of the major problems hindering the applications of OSCs is their susceptibility to degradation. Much research has been done on understanding the degradation mechanisms in OSCs, particularly under extreme and sustained environmental conditions, such as low and high temperatures. While these studies provide valuable insights, they do not fully reflect the conditions most organic solar cells encounter in real-world environments. In everyday situations, environmental factors such as temperature, humidity, and light are not static but fluctuate over time. Therefore, it is essential to understand how these devices degrade not only under constant stress but also when exposed to changing conditions. This work investigates how BTP-4F non-fullerene organic solar cells degrade when subjected to several environmental cycles. Advanced characterization techniques, including grazing-incidence X-ray scattering (GIXS) and atomic force microscopy (AFM), are employed to track both in-situ and ex-situ structural changes in the active layer of OSCs, providing detailed insights into the degradation mechanisms.

Speaker: Lixing Li

1:45 PM P-047: Transmission Electron Microscopy – complementary technique for Neutron Scattering

Transmission electron microscopy (TEM) is used to produce images by illuminating a sample with an electron beam in a high vacuum. That makes it a powerful technique i.a. in soft matter studies. With the TEM, real space investigations are performed to obtain knowledge about particles shape, size and size distribution, self-assembly and aggregation.
The JCNS Transmission Electron Microscopy laboratory offers preparation and investigation of the samples to users who wish to support their neutron experiments done at the MLZ using (Cryo-) TEM.
The TEM instrument will be described, as well as the equipment for sample preparation.

Speaker: Joanna Michalska-Walkowiak (Jülich Centre for Neutron Science (JCNS) at MLZ, Forschungszentrum Jülich GmbH, Garching, Germany)

1:45 PM P-007: TUM Sample Environment: Preparing for user operation relaunch 2025

The Heinz Maier-Leibnitz Zentrum (MLZ) is a leading centre for cutting-edge research with neutrons and positrons. As part of the user operation at the MLZ, TUM Sample Environment (SE) group assists in the installation and operation of complex SE equipment on instruments, providing experimental support to MLZ scientists as well as maintenance and repair of equipment.
In particular, the year 2024 has been a period in which TUM sample environment group has faced the challenge of carrying out the necessary tasks in order to relaunch of operations in 2025. Among the most relevant actions, we can mention: definition of sample environment requirements per instrument, training of new personnel, test, repair and preventive maintenance of SE equipment and auxiliary components, refurbishment of workspaces, etc.
In this poster, you will have the opportunity to see the status of the Sample Environment activities in order to start the operation of the next reactor cycle

Speaker: Andreas Buchner

1:45 PM P-054: Unveiling the Kinetics of Block Copolymer Micelles Close Packing by In Situ GISAXS

Packing spheres has long been a key topic in science. While hard spheres often form dense, close-packed structures like face-centered cubic (FCC) lattices, soft spheres, such as block copolymers in selective solvents, tend to arrange into less dense structures. However, when using block copolymer templates in the sol-gel method, these soft spheres can achieve close-packed structures. In this study, in situ grazing-incidence small-angle X-ray scattering (GISAXS) is used to examine the self-assembly and co-assembly processes during the formation of close-packing structures. The results reveal that the hybrid films preferentially develop an FCC structure with cluster nuclei. After the polymer template is removed, a superlattice-like mesoporous metal oxide film is obtained, showcasing the potential for advanced applications due to its well-organized nanostructures.

Speaker: Guangjiu Pan (Technische Universität München, Fakultät für Physik, Lehrstuhl für Funktionelle Materialien)