Page 16 - ILL Annual Report 2019

COLLEGE INTRODUCTIONS
COLLEGE 1 – APPLIED MATERIALS SCIENCE, INSTRUMENTATION AND TECHNIQUES
S. Cabeza (College 1 secretary)
College 1 deals with applied physics and new instrumentation techniques in neutron scattering. The main areas covered are metallurgy, applied neutron scattering, cultural heritage, new neutron-scattering techniques, instrumentation and scientific computing. This college
hosts proposals from a diverse user community ranging from polymer scientists to metallurgists and nuclear physicists.
Neutron strain characterisation on SALSA accounted for around half of all the proposals submitted in 2019, and neutron-imaging studies will continue in 2020 with NeXT.
Batteries and metal additive manufacturing remain hot topics for neutron investigations, with both in situ and in operando experiments in these areas being popular. The ILL is committed to supporting this kind of work and has provided new set-ups and methodological improvements in the last year. Important contributions to the nuclear physics community have also been achieved recently, with studies on the double-differential neutron cross section of compounds for new, very-cold-neutron moderators, for example. In addition, spatial resolution and near-surface characterisation at SALSA is gaining attention, while the first stroboscopic measurements studying plasticity in high-cycle fatigue tests have also been successful.
The ILL’s efforts over recent years to reach out to the materials science and engineering community have resulted in increasing interest in our techniques and the arrival of new users. Many of College 1’s proposals include industry-related topics and collaboration with industry.
COLLEGE 2 – THEORY
N. Garcia (College 2 secretary)
College 2 covers three areas of science: soft matter, electronic structure
and magnetism. The Theory Group delivers independent and highly advanced research on these topics while continuously benefitting from collaborations with experimentalists inside and outside the ILL. The College has a strong tradition of hosting visiting scientists working on topics such as geometrically frustrated and strongly correlated magnetism, the impact of human mobility on the spread of disease, coarse-graining of bovine serum albumin and polymer nanocomposites.
This year, some members of the group have been involved in neutron experiments at the ILL and at external labs in Europe and beyond. Others have provided theoretical input for local experiments, illustrating our desire to ensure a strong theoretical background to the interpretation of experimental data.
It has, therefore, been an exciting year for ideas and interaction. Our three postdocs are reaching the end of their time with the Theory Group and others will soon be arriving. Thus, we look forward to 2020, to the start of new projects and to the pursuit of those currently showing good promise.
COLLEGE 3 – NUCLEAR AND PARTICLE PHYSICS
C. Michelagnoli (College 3 secretary)
College 3 is dedicated to nuclear and particle physics research. In 2019,
STEREO moved on to data-taking phase 3; this follows refinement of the analysis of data from phase 2 and submission of a detailed paper on oscillation analysis in relation to improving constraints on a hypothetical sterile neutrino. In addition, PERKEO was installed at PF1B, with considerable support from several of the ILL’s technical services, while measurements of the Fierz interference term from the beta spectrum of unpolarised neutrons began and data is now being collected.
LOHENGRIN saw another successful fast-timing campaign, with several experiments measuring the lifetimes of excited nuclear states down to below 10 ps. Various types of diamond were also studied as fission fragment detectors; this is particularly important for the FIPPS fission campaigns. Furthermore, a number of experiments were performed on FIPPS using additional HPGe clovers from IFIN-HH, including a 233U fission run with active target and the first experiment using a 2 GBq radioactive 63Ni target (to shed more light on shape isomerism in light nuclei).
COLLEGE 4 – MAGNETIC EXCITATIONS
L. Mangin-Thro (College 4 secretary)
College 4 is dedicated to inelastic neutron scattering studies in
magnetic compounds. A healthy number of proposals were received in 2019, with a significant increase in the second round. The proposals were well distributed over all the spectrometers designed for magnetic excitations, with the usual heavy demands on magnetic frustration, quantum magnetism and superconductors being observed. The actual trend, however, is towards ever more sophisticated set-ups. For the first time in several years a measurement requiring high pressure to study a quantum phase transition was proposed. It should be noted that there were also new proposals on molecular magnets—a very strong topic for College 4 in the past.
The thermal time-of-flight spectrometer PANTHER is now available, and the first commissioning experiments will study powder samples. In subsequent rounds, proposals with single crystals and various sample environments, including dilution fridges and magnets, will be investigated.
COLLEGE 5A – CRYSTALLOGRAPHY
O. Fabelo (College 5A secretary)
College 5A focuses primarily on fundamental science, including crystallographic studies using crystalline materials. The College uses both powder and single-crystal materials. The main objective of the experiments carried out in 2019 was to investigate the correlation between crystal structures and physical properties. Neutron techniques provide unique opportunities for determining the structural features underlying the physical properties of crystalline materials and property–material relations.
Over the last year, College 5A studied hydrogen storage materials, ionic conductors (cationic and anionic), superconductors, catalysts, shape-memory materials, high-voltage battery materials, crystal structure determination in inorganic materials, pharmaceutical compounds, hybrid materials and co-ordination polymers. More recent calls for proposals reveal a noticeable interest in materials for energy applications, including batteries and photovoltaic materials.
Our user community includes chemists as well as solid-state and condensed-matter physics researchers, originating for the most part from the ILL member countries. We should, however, stress the international character of our research teams, reflecting a well-established neutron network across international laboratories. As for ILL instruments,
College 5A uses a broad range, most of them diffraction-related and showing a trend towards non-conventional conditions.
ANNUAL REPORT 2019