Hydrogen storage technologies in low weight hydrides promise to help with the global aim of CO2-emissions reduction. High mass energy densities are needed e.g. for heavy-load long distance mobility like trains, trucks, and airplanes. One of the potential reaction based systems is Mg(NH2)2+LiH with a reversible hydrogen capacity of 5.6 wt.% below 200oC. The kinetics of hydrogen...
In-situ experiments with ultracold neutrons (UCN) present an opportunity to profit from long observation times and high densities, but must confront numerous practical challenges. I will discuss the challenges and opportunities connected with in-situ measurements of the neutron's electric dipole moment, focusing on a modular multichamber concept based on UCN production, storage, and...
Clamp cells optimized for neutron scattering at low temperatures on the instruments DNS, MIRA, HEiDi, and POLI at the Heinz Maier-Leibnitz Zentrum [1] will be presented. The monobloc cell is available in two variants made of a CuBe alloy and a NiCrAl alloy, operational up to about 1.1 GPa and 1.5 GPa, respectively. Measurements aimed to elucidate magnetic properties are now possible due to the...
Heavy mineral separates from Hungarian sand samples were measured by instrumental NAA at the Budapest Research Reactor (BRR), but the amounts and weights of them were way too small to also analyze them effectively at the PGAA station of the BNC. Combined PGAA and in-beam NAA experiments were made on the samples at FRM-II to study their possibilities.
First, the mineral separates were...
Magnetic dipole traps have demonstrated good confinement properties for both non-neutral and quasi-neutral plasmas, making them highly suitable 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,...
Although the idea of a ‘cooperativity’ length scale ξ related to the glass transition is now wide-spread, there is much less consensus on whether this length scale can be related to thermodynamic fluctuations and, if yes, whether one has to consider temperature fluctuations δT. The crucial experiment to this end has to compare values of ξ from ‘thermodynamic’ formulae to independent values...
It is a common practice in science to approach a problem simultaneously from the theoretical and experimental side. However, it is important to compare theory and experiment as directly as possible in order to validate that the theory describes reality. This contribution focuses on bridging the gap between simulations and scattering experiments with neutrons and X-rays.
Although...
The itinerant ferromagnet nickel has a long history of studies investigating its spin wave and critical, paramagnetic scattering over a large range in temperature. Close to $T_C$ = 631 K, the behavior of Ni, as observed with neutron scattering, is well explained by mode coupling and renormalization group theory calculations based on the isotropic Heisenberg model. According to scaling theory,...
The water dynamics is key to functionality and phase behavior of synthetic and biological polymers. Responsive polymers react strongly to external stimuli such as temperature and pressure triggering chain collapse and phase separation. We investigate the dynamic behavior of hydration water in a 25 wt% aqueous poly(N-isopropyl acrylamide) (PNIPAM) solution in dependence on temperature (25 –...
Among new alloy systems being developed to supplement Ni-based superalloys in gas turbine applications, the Co-Re-based alloys show promise because of their excellent specific strength and relatively high melting range (1490°-1560°C). Alloying elements with various functions are added to these alloys. For example, Cr, and Ni, for oxidation resistance. Since the Co matrix undergoes an...
Optimization of the shape and intensity of a positron beam requires suitable beam diagnostics. The speed with which a low-energy positron beam can be optimized prior to a measurement is presently limited by available detection techniques, resulting in a sizeable loss of beam time to optimization. In this talk we will present two novel approaches to the detection of the position, shape and...
Magnetic excitations in stripe-phases of $La-$based hole-doped $214-$ nickelates, especially in the $Sr-$doped ones, have been vigorously explored using inelastic neutron scattering (INS) studies. In $Sr-$ doped samples, the spin stripe correlation is relatively short-ranged due to unavoidable disorder introduced by the randomly distributed dopant. However, often the results have been compared...
We report a comprehensive study of single crystals of the noncentrosymmetric rare-earth compound $\mathrm{EuPtSi}_{3}$ grown by the optical floating-zone technique. Measurements of the magnetization, ac susceptibility, and specific heat consistently establish antiferromagnetic order of localized $\mathrm{Eu}^{2+}$ moments below the Néel temperature $T_{\mathrm{N}} = 17~\mathrm{K}$, followed by...
We aim to apply “materials informatics” (MI) for the development of high-performance anion-exchange membranes (AEM), which may be applied to next generation energy devices, such as non-platinum fuel cell hybrid vehicles and all solid secondary batteries. Currently, there are two major obstacles to using MI for such systems: the unclear higher-order (hierarchical) structure/function...
Supramolecular polymers offer exciting prospects for materials with novel properties because of the reversibility of the non-covalent interactions, like H-bonding.[1,2] This work aims to unravel the correlation between H-bonding association and main chain polarity in supramolecular polymer melts. These are based on poly(ethylene)oxide (PEO) and poly(propylene)oxide (PPO) (in order of...
The ultimate goals of the APEX (A Positron Electron eXperiment) Collaboration are the generation and investigation of conned, strongly magnetized, electron-positron plasmas in the laboratory. The mass symmetry of such plasmas simplifies many aspects of their physics, as has been described in more than four decades of theory/simulation predictions.
Our road map to conducting experimental...
In the last two years the neutron optics group of FRM II has successfully sputtered non-depolarizing m=2 Cu/Ti supermirrors, which have been prepared with a standard DC magnetron sputtering facility. Control on the roughness grow and interdiffusion allowed us to get a very good maximum angle of total reflection (ca. 0.21°/λ) and polarized neutron reflectivity above 90%, as measured at the...
Structural investigations on functional ceramics is an important tool for material characterisation and tailoring of properties for specialised applications. This frequently requires high angular resolu-tion to resolve highly correlated phase coexistences or subtle structural features. The most common tool is high resolution X-ray or synchrotron radiation. Especially for in situ investigations...
The last two decades have seen the demonstration of the feasibility of neutron diffraction in fields as high as 40 T with the development of dedicated pulsed field devices based either on short or long duration pulsed magnets [1, 2]. These breakthroughs have allowed to extend the field limits beyond current superconducting (15 T split, 17 T solenoid) and resistive installations already...
Imaging techniques based on neutron beams are rapidly developing and have become versatile non-destructive analysing tools in many research fields. Due to their intrinsic properties, neutrons differ strongly from electrons, protons or X-rays in terms of their interaction with matter: they penetrate deeply into most common metallic materials while they have a high sensitivity to light elements...
Pressure is next to temperature the key thermodynamic parameter for the exploration of condensed matter. In this talk I will survey the state of the art of high pressure neutron scattering, covering both diffraction and inelastic scattering. I will focus on more recent methods able to reach pressures of 10 GPa and beyond, relevant for research on hard condensed matter. My talk will be largely...
Neutrons are powerful and have unique characteristics, which make possible non-destructive and operando characterizations of cylindrical and prismatic Li-ion batteries. X-rays are an equally competent tool that can provide complementary information on pouch type Li-ion cells during cell operation. Expectedly, both are also capable of providing information at material and electrode level. This...
The NOPTREX collaboration performs neutron spectroscopy measurements on p-wave resonances to quantify P-odd/T-odd measurement sensitivity. Beam-port adaptations to POLI would enable one of the highest fluxes of polarized eV neutrons in the world aided by the new 3He polarizer and analyzer. The 139La 0.7 eV p-wave resonance amplifies both parity-odd (P) and time-reversal odd (T) effects from...
Data obtained at a publicly funded research facility such as MLZ becomes available to other researchers after some period of time. The motivation for this policy is to make it possible to reuse data or verify published results. Given the huge variety of instruments, methods, and the extreme complexity of some of the experimental workflows, reuse of such data becomes absolutely impossible...
Lattice vibrations, i.e., phonons are ubiquitous in solids and getting detailed knowledge on them was one of the success stories of early inelastic neutron scattering. Nowadays, large neutron detectors along with ab-initio lattice dynamical calculations allow comprehensive experimental and theoretical mapping of phonon properties. However, calculations of lattice dynamics at or close to...
Orthorhombic Barium di-silicide (BaSi2) is an emerging sun light conversion material for thin film solar cells, owing to its suitable bandgap, high light absorption coefficient, and long minority-carrier lifetime. Moreover, Ba and Si are very abundant and environmentally benign materials. The nature of defects in BaSi2 thin films grown by Molecular Beam Epitaxy (MBE), Thermal Evaporation (TE),...
The neutron strain pilot projects within H2020- Sine2020 and BRIGHTNESS2 towards European neutron landscape & users have been key for facilitating industry access and collaborations in a regular basis. The shortcomings reducing the industrial experimental throughput are well known and very similar to all facilities. A central issue is the non-acceptance by industry to use the neutron technique...
Using the amide I band, infrared (IR-) spectroscopy can give information on the fold of the protein and also allows to follow aggregation phenomena. Small angle neutron scattering also reports on the global structure of proteins in solution and can give information on the shape of growing aggregates or folded proteins in solution.
We would like to explore the capabilities of infrared...
Fabricating functional material relies on non-equilibrium hydrodynamic flows. Spray deposition using atomization of complex liquids leads to a deposition of droplets on a substrate. The solvent evaporates and induces a complex flow in the dispersion. This leads to a nanostructuring of the nanoscale ingredients of the dispersion. Using cellulose nanofibrils and water as solvent, we have...
New high-flux and high-brilliance neutron sources demand a higher count-rate capability inneutron detectors. In order to achieve that goal, the Solid-State Neutron Detector (SoNDe)project developed a scintillation-based neutron detector. It is capable of fully exploiting theavailable flux current and coming neutron facilities, such as the European Spallation Source(ESS).[1] In addition to...
Inspired by the possible storage of nuclear waste in impermeable rock salt formations, numerous theoretical and applied studies have investigated the effect of gamma irradiation on the structural properties of halite over the last five decades. An important discovery has been the gamma irradiation - induced decoration of othervise invisible lattice defect substructures in this optically...
JALOUSIE is a modularized neutron detector concept that has been realized for the first time in POWTEX. It was developed to serve as alternative for classical 3He position sensitive detector tubes as used for large neutron scattering instruments. POWTEX has been fully instrumented at FRM II along this concept. Further JALOUSIE based systems are under production for DREAM and MAGiC at ESS.
The...
The Jülich Centre for Neutron Science offers the opportunity to fabricate thin film samples by Molecular Beam Epitaxy (MBE). We are running an MBE setup with effusion cells, electron guns for electron beam evaporation and a plasma source for use with oxygen or nitrogen. A large variety of deposition materials can be used. Please express your ideas! In the past, we have produced simple Fe...
The structures of materials under study are of ever-increasing complexity, now often exhibiting short-range order, nano-structure, or correlated disorder that affect their physical and/or functional properties. In order to quantify this increasing structural complexity, a maximal amount of information needs to be extracted from e.g. neutron diffraction patterns, whence the importance of...
