At the end of 2019 two major European neutron sources will stop their operation. With the closure of Orphée, French users will lose their national source, with the closure of the BER2 at HZB, German users will focus even more on the MLZ at Garching.
Furthermore, the international users of both facilities will put even more pressure on the availability of beam time at our international source, the Institute Laue Langevin (ILL), and also at the MLZ. However, ESS will come into full operation in the late twenties only. In particular for the French user community, this means the risk of losing knowledge in neutron science, in the period between the closure of Orphée and the getting into operation of ESS. A first attempt to bridge this gap is made by additional CRG instruments at ILL and SINQ. In the interest of keeping the European leadership in neutron science, French scientists are warmly welcome to become an active partner at MLZ.
In this framework, the workshop will discuss opportunities of an enhanced cooperation between French and German neutron scientists covering topics from innovative instrumentation to exploring new fields in neutron science.
The Directors of 2FDN and MLZ look forward to welcoming French and German neutron scientists at this workshop.
On behalf of 2FDN On behalf of MLZ
Virginie Simonet Peter Müller-Buschbaum
Fabrice Cousin Stephan Förster
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Influence of pressure on the formation of mesoglobules of the thermoresponsive polymer poly(N-isopropyl acrylamide) (PNIPAM) in aqueous solution, when heated above its cloud point is investigated using very small angle neutron scattering. At a critical pressure, a remarkable increase in the size of PNIPAM mesoglobules is noted. We presume that the observed increase in the size of mesoglobules is due to the pressure induced enhancement in hydration and subsequent aggregation of mesoglobules.
We routinely supply in-situ dynamic light scattering with one fixed scattering angle at the instrument KWS-2 at MLZ to users who would like to control their sample during the neutron measurement. Recently, we have successfully tested a three angle dynamic light scattering set-up at KWS-2. For the Jülich neutron spin echo spectrometer we are currently developing a prototype sample environment which includes two scattering angles and a transmission detector.
Using quasi-elastic neutron scattering, we study the pressure-dependent hydration behavior of an aqueous poly(N-isopropylacrylamide) solution during heating through its cloud point (CP). At high pressure, the hydration water diffuses more rapidly than at low pressure, which indicates enhanced hydrophobic hydration. An abrupt dehydration, mainly of the hydrophobic groups, is observed at the CP at low pressure, whereas both hydrophilic and hydrophobic groups dehydrate gradually at high pressure.
Compared to poly(N-isopropylacrylamide) PNIPAM, poly(N-isopropylmethacrylamide) PNIPMAM shows different behavior, though it has a similar chemical structure, only with additional methyl groups on the backbone, e.g. a higher transition temperature (43 °C instead of 32 °C). We studied the temperature-dependent phase behavior of PNIPMAM in D2O using small-angle neutron scattering. Different from PNIPAM, inhomogeneities and physical crosslinks appear in the one-phase state due to the methyl groups.
The MLZ provides a number of different instruments – tailored to different scientific problems – to scientists from all over the world.
As control-suite NICOS is established, providing a common user interface with scripting capabilities and data collection. The hardware abstraction is mostly implemented in 'entangle', a TANGO device server written in Python, but also EPICS, SECoP, and selected other protocols are in use. Finally, a PLC interface specification effectively allows PnP of hardware.
Although a silicon-based electrode is a promising candidate as anode in Li-ion batteries, repeated cycling results in significant morphological changes of the silicon particles leading to formation of highly porous silicon structures. We applied small-angle neutron scattering (SANS) with selective contrast matching to provide quantitative insights into the solid-electrolyte-interphase (SEI) coverage around the silicon particles and filling of the evolving porosity within the electrode.
A new multianalyzer Bambus is being constructed at Panda, MLZ. The objective is to construct broad reciprocal space maps at multiple energy transfers, in order to get insights of broad features at low energy or study complex dispersion laws. Because this spectrometer is designed as a complementary option to the normal TAS mode, a fast switch between the two setups is foreseen. The general concept will be presented together with the final design, and the results obtained with two prototypes.
Major instrument upgrades at DNS, including a new Fe/Si supermirror based focusing polarizing bender, and a 300 Hz disc chopper system, have been accomplished recently. This has opened up possibilities to combine polarized neutrons with time-of-flight spectroscopy for the studies of exotic magnetic order and excitations in emergent quantum materials. In this poster, an overview about those upgrades and some selected recent examples will be given
"Energy research with Neutrons" (ErwiN) addresses the need for rapid data collection and studies of small sample volumes in the range of mm3, which are the main driving force for the concept of a high-throughput monochromatic diffraction instrument at the MLZ. ErwiN will especially be suited for addressing structural studies and its uniformity of energy-related systems and materials by using simultaneous bulk/spatially resolved NPD
Ni superalloys are used for high T applications that require good mechanical properties. The aim of reaching higher service T forces the development of new materials. VDM alloy 780 Premium has been developed for higher service T and this work shows its in-situ structural characterization by means of XRD and ND. The morphology is studied by SEM and SANS, the solvus T of the different phases is determined and the structural properties correlated with hardening of the materials.
The cold-neutron three-axis spectrometer MIRA is an instrument optimized for low-energy excitations. Its excellent intrinsic 𝑄-resolution makes it ideal for studying incommensurate magnetic systems. MIRA is uses advanced neutron focusing optics such as elliptic guides, which enable the investigation of small samples under extreme conditions. Scientific topics include the investigation of complex inter-metallic alloys and spectroscopy on incommensurate magnetic structures.
KOMPASS is a polarized cold-neutron three axes spectrometer currently undergoing its final construction phase at the MLZ in Garching. The instrument is designed to exclusively work with polarized neutrons and optimized for zero-field spherical neutron polarization analysis.
 M.Janoschek et al., NIMA 613 (2010) 119
 A.C.Komarek et al., NIMA 647 (2011) 63
The construction of KOMPASS is funded by the BMBF through the Verbundforschungsprojekt 05PK16PK1.
The neutron single crystal diffractometer BIODIFF is dedicated to structure determination of proteins. Typical scientific questions address the determination of protonation states of amino acid side chains, the orientation of water molecules and the characterization of the hydrogen bonding network between the protein and an inhibitor or substrate. BIODIFF is designed as a monochromatic diffractometer and is able to adapt the wavelength to the size of the unit cell of the sample crystal.
STRESS-SPEC is the dedicated diffractometer for materials science applications at MLZ. It offers high thermal neutron flux and is mainly used for fast residual strain and texture (bulk, local or gradient) measurements. Here we will give an overwie on the current status of the instrument.
As we pioneered the use of robotic sample manipulation at STRESS-SPEC, future improvements of the position accuracy of this device through a new adaptive control system will be also outlined.
NECTAR is a superior beam-line with access to fission neutrons for non-destructive inspection of large and dense objects, where thermal neutrons or X-rays face limitations due to their comparatively low penetration. With the production of fission neutrons at the instrument, gamma rays are inherently produced in the same process.
Here we present the advantages of combining the information gained from neutron imaging in conjunction with gamma imaging at the NECTAR beam-line.
Lithium ion batteries most commonly use graphite as an anode material. Understanding the dynamical processes of the lithiation and delithiation play a crucial role in understanding performance, degradation of graphite based anodes. Our operando neutron diffraction of LiCoO2/graphite cells showed the occurrence of inhomogeneously delithiated graphite anodes.Phase coexistence of multiple stages is followed by relaxation into a single phase or a two phase mixture close to the mean lithium content.
In addition to the “normal triple axis” mode, PUMA is equipped with the multi-analyzer setup consisting of 11 arbitrarily configurable analyzer-detector channels suited for kinetic experiments to realize an entire (Q,E)-scan in a single shot. Moreover, the same setup can be used also for polarization experiments to determine the spin flip and the non-spin flip components simultaneously at the same state of the sample. I will present the current status of PUMA with the multi-analyzer setup.
Investigations of magnetic excitations focus on new magnetic materials, quantum magnetism, superconductivity, heavy-fermion or low-dimensional systems, frustrated and multiferroic materials. PANDA, being a high-resolution, high-flux cold TAS spectrometer with a remarkably low background, successfully contributes with high-level experiments to a broad variety of these scientific topics. We here present a selection of recently published results where PANDA experiments significantly contributed.
PUMA is optimally designed for measuring inelastic neutron scattering which covers a wide energy and momentum range. Owing to high thermal-neutron flux at FRM-II, PUMA is recognized as one of the most powerful thermal neutron TAS. This attracts various user community groups to conduct challenging measurements on PUMA such as magnetic fluctuations in unconventional superconductors or spin-waves in quantum magnets. Here we present selected research results mainly acquired on PUMA in recent years.
Poly(2-alkyl-2-oxazoline) molecular brushes, featuring PMeOx-b-PBuOx side arms, are investigated in aqueous solution. While hydrophobic PBuOx is attached to the backbone, storing the anticancer drug, Paclitaxel, the hydrophilic PMeOx is at the periphery, facilitating transport in water. With small-angle neutron scattering, the structure of the PTX-loaded molecular brushes with different backbone length was revealed, disclosing the effect of the molecular architecture on the drug-loading ability.
Stimuli-responsive physical hydrogels change their properties upon a small change of the environment and may be used as fast sensors, for drug delivery or for tissue engineering. In this work, we investigate the telechelic pentablock terpolymer P(n-BuMA-co-TEGMA)-b-PDMAEMA-b-PEG-b-PDMAEMA-b-P(n-BuMA-co-TEGMA) in dilute aqueous solution as a function of temperature and pH using small-angle neutron scattering (SANS), elucidating the core-shell structure and the conformation of chains in the shell.
The neutron imaging beam line ANTARES is located at a cold neutron beam port of FRM II and offers high sensitivity, high spatial resolution and excellent flexibility for sample environment and other components. ANTARES provides many advanced options: a double crystal monochromator, a neutron velocity selector, grating interferometer and an option for imaging with polarized neutrons.
We will show the instrument ANTARES as well as typical applications and recently performed scientific projects.