Page 14 - ILLS Annual Report 2018

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 topics covered are metallurgy, applied neutron scattering, cultural heritage, new neutron scattering techniques, instrumentation and scientific computing. Stress mapping accounts for about half of the proposals submitted, and during the past year metal additive manufacturing was a hot topic for neutron residual stress characterisation. Furthermore, a certain proportion of the proposals represent current industrial collaborations.
SANS is an attractive, yet underused, technique for the whole materials science community–the College still has a few days available (with Highlight proposals not allocated in the last round). Nevertheless, the ILL’s efforts to reach out directly to the materials science and engineering community are increasing, as are the number of proposals we are receiving as a result. A growing number of non-member countries are also presenting highly ranked experiments. In situ and operando work is needed in all fields and on all instruments, and users are collaboratively engaged in proposing and developing new sample environments at the ILL. These include, for example, the set-up for in situ metal printing on SALSA (with the Fraunhofer-IWS team), the development of a confined shear cell (with Malmo University) on FIGARO and the development of a method proposed recently on D33 (with PSI teams) to deal with ToF Bragg imaging.
COLLEGE 2 – THEORY
E. Rebolini (College 2 Secretary)
College 2 focuses on research fields covering hard condensed matter,
electronic structure and soft matter. It pursues independent research in synergy with researchers from the other Colleges and ILL users, and hosts many long-term and occasional visitors as part of successful collaborations. In 2018, a new post-doc and a new PhD student joined the ILL Theory group, working respectively on magnetism in high-Tc superconductors and finite-temperature spin dynamics. A long-term visiting PhD student also joined us for a year to conduct simulations
of iron-sulphur metalloproteins and their redox potentials. In 2018, College 2 also reached out to experimentalists by organising the Theory day ‘Theoreticians at the ILL–at your service’ as well as a series of lectures within the framework of the ILL’s PhD seminars.
COLLEGE 3 – NUCLEAR AND PARTICLE PHYSICS
S. Degenkolb (College 3 Secretary)
College 3 uses the ILL reactor to address questions in nuclear and
particle physics, including experiments concentrating on particles
other than the neutron and studies of the neutron itself. In 2018, the STEREO experiment published its first constraints on sterile neutrinos in the eV mass range, proposed to explain observations of unexpectedly low electron antineutrino flux at nuclear reactors. The decennial conference on ‘Particle Physics at Neutron Sources’ (PPNS-2018)
was co-organised with the LPSC, and hosted there in May. A total of 136 participants attended, and celebrated 50 years since the first experimental observations of ultracold neutrons. LOHENGRIN (PN1) saw a series of successful nuclear spectroscopy experiments using conversion electron and fast timing set-ups, respectively complementing spectroscopy of the 2012 EXILL campaign, and FIPPS today, with mass-separated fission products. FIPPS had its first fission experiments during cycle 184, using an active target with 235U diluted in a scintillator. This system, used to study structure in neutron-rich nuclei,
combines for the first time the selectivity of multiple-gamma-ray coincidences with tagging of neutron-induced fission events.
COLLEGE 4 – MAGNETIC EXCITATIONS
L. Mangin-Thro (College 4 Secretary)
College 4 is dedicated to magnetic excitations in ordered and disordered magnets, superconductors and frustrated systems. Both the subcommittees and the ILL’s 2018 Highlights confirm interest in the latter to be particularly strong: two articles deal with geometrically frustrated magnetism in a pyrochlore and a kagome antiferromagnet respectively; another concerns
a low-dimensional material, an Ising-like antiferromagnetic spin chain. In addition, a hyperfine interaction study has been performed on double perovskites. From an experimental point of view, significant demand for IN4 was observed during the last proposal round. This could not be satisfied, however, due to the absence of this thermal time-of-flight spectrometer following its decommissioning. To take its place, the new instrument PANTHER is being built as part of the Endurance suite of upgrades. Another development in terms of instruments concerns IN5, which should soon benefit from a new beam guide, increasing flux by a factor of three. Moreover, considerable effort is being made to achieve higher fields (10T), a sample environment also in high demand in the last proposal round.
COLLEGE 5A – CRYSTALLOGRAPHY
O. Fabelo (College 5A Secretary)
During 2018, College 5A accepted 87 proposals carried out on ten
different ILL and CRG instruments. The samples studied were mainly
single crystals or powder samples, although some amorphous or poor crystalline materials were also treated during the three reactor cycles.
This number of proposals, with its slight increase with respect to previous years, continues an increasing trend. The scientific topics covered include hydrogen storage materials, ionic conductors (cationic and anionic), superconductors, catalysts, memory shape materials, high-voltage battery materials and the anharmonicity of light atoms, among others. It should be noted that Materials for Energy is an area that, as in previous years, has received significant support from the College 5A community, highlighting the importance of neutron scattering techniques for shedding light on the physics behind these prominent materials. College 5A’s user community
is formed largely of experienced and well-established groups within the chemistry, solid-state and condensed-matter physics communities, and spans 14 different countries. Moreover, our user database has expanded with the inclusion of several new research groups, thereby ensuring the health of the community over the coming years.
COLLEGE 5B – MAGNETIC STRUCTURES
N. Qureshi (College 5B Secretary) and D. Honecker (focus group Secretary) College 5B deals with static magnetic properties of crystalline materials, investigated by means of powder or single-crystal diffraction—including more sophisticated techniques such as spherical neutron polarimetry, as can be seen from two of this year’s Magnetism Highlights—as well as small-angle neutron scattering (SANS) and reflectometry techniques.
Strong interest in frustrated compounds with exotic ground states, some of them in form of thin films and nanomaterials, persists. Multiferroic materials remain ‘trendy’, but an upturn in the trend for low-dimensional systems can also be observed.
The search for new classes of skyrmion-hosting materials and studies of the phase stability of chiral magnets are at the focus of the SANS community.
ANNUAL REPORT 2018