Infrastructure for neutron science with contributions from Uppsala University
Scientists from Uppsala University are actively engaged in method and instrument development for neutron-based science. The reflectometer Super-ADAM, the only neutron infrastructure completely owned by the Swedish community, is also operated by Uppsala University.
The neutron reflectometer Super-ADAM
Super-ADAM is a Swedish national research infrastructure located at the Institut Laue-Langevin (ILL) in Grenoble, France. The neutron reflectometer offers a large experimental area and modular design as well as access to diverse sample environments making it a valuable tool for a wide range of research topics, including but not limited to life sciences and food, quantum materials, and energy materials. You can read more about Super-ADAM at the website of the Division for Materials Physics.
Contributions to ESS
The European spallation source (ESS) is set to be the world's most powerful accelerator-driven neutron source and expected to advance research in materials and life sciences, energy, environmental technology, cultural heritage and fundamental physics. The initial layout includes 15 beamlines and is currently under construction in Lund, Sweden.
The FREIA Laboratory at Uppsala University is contributing to the Fast Reflectometer for Extended Interfacial Analysis (FREIA) beamline.
FREIA
The Fast Reflectometer for Extended Interfacial Analysis (FREIA) to be installed in ESS is a horizontal reflectometer, which will provide unprecedented versatility with its 3 modes of operation: standard geometry, inverted geometry and unique capability of doing kinematic analysis. Its construction pioneers the use of elliptical guides and a fast shutter system, this way scientist will be able to do much faster measurements opening the realm of kinematic studies to the world.
The FREIA Laboratory is contributing to this world-leading instrument with the design of the detector bench and flight tube. These systems accurately position the detector in the path of the reflected neutrons and minimize the loss of them during the trajectory from the sample to the detector. The flight tube also allows the installation of a future polarization upgrade for further enhancing the capabilities of the instrument. The FREIA Laboratory, in close collaboration with ISIS Design Division (STFC) and partners at the ESS, is developing the mechanical design and dimensioning of these systems.
FREIA is a multi-purpose instrument with a horizontal sample geometry and a broad simultaneous momentum transfer (Q-range) for structural and kinetic studies. The instrument design has been optimised for the studies within condensed matter and life sciences. For maximizing the benefit of the high ESS flux for kinetic studies, a novel collimation system for measuring the full Q-range simultaneously has been designed. For example, it will be possible to study the kinetics of biochemical reactions in H2O like liquid-liquid interfaces e.g. oil-water.
Kinetic experiments on FREIA are done by selecting a part of the neutron beam from a beam with broad divergence, using two sets of precision slits and a system of fast beam shutters. The beam paths are thus constrained by three apertures and one, well defined-beam, can be formed by the collimation system on a per-pulse basis. The FREIA Laboratory is developing the fast shutter mechanism, operated in vacuum, which ensures that the aperture area is blocked and unblocked with a reaction time of 15 ms. Further work will be required to verify the neutron absorption performance and in optimizing the control system.
The number of ESS beamlines is planned to increase to 22 in the future, and Uppsala University is involved in several of the proposed concepts.
ECHIR
A close collaboration between Uppsala University, ESS, and several industrial partners constitutes the ECHIR (ESS Chip Irradiation) project. The goal of the project is to establish a high-flux neutron irradiation beamline for testing radiation effects in microelectronics, as for example used in aviation, power electronics, deep neural networks and board-level integrated systems. ECHIR would strengthen the development of components and systems resilient to radiation, increase Europe’s technological autonomy, and improve supply‑chain security in the semiconductor industry.
GERSEMI
GERSEMI is a proposal for a neutron spin echo (NSE) spectrometer at ESS. NSE is a technique suited to study dynamics in condensed matter, for example protein domain motions and biomembrane fluctuations, polymer chain dynamics or magnetic relaxations. The long and strong pulses of ESS would allow for high-resolution measurements.
SAGA
SAGA (Surface Analysis using Grazing Angle neutron scattering) is a Swedish proposal for a grazing-incidence small-angle scattering (GISANS) beamline at ESS. SAGA would be one of only two dedicated GISANS instruments in the world and the only one connected to a source with high brightness. The GISANS technique would benefit research on materials surfaces and interfaces, including liquid interfaces. Read more about the proposed instrument design and emerging science cases on the SAGA website.
Development of instrument components and methods
Upgrade of the OSIRIS spectrometer
OSIRIS is a high-resolution spectrometer located at the ISIS Pulsed Neutron and Muon Source, England. The instrument is optimised for probing slow dynamics and has been used for studies of hydrogen dynamics in proton conducting oxides and metal hydrides, with a view towards their application in, e.g., fuel cells and hydrogen storage. A collaboration of ESS, ISIS, Chalmers University of Technology and Uppsala University contributed to an upgrade of the spectrometer, namely with a new supermirror guide and a silicon analyser leading to five-fold increase in flux and a 2.5 times better energy resolution, respectively.
Port-GISANS
Grazing-incidence neutron scattering (GISANS) can provide unique information on soft-matter systems and magnetic structures, even if they are buried beneath a surface. However, the widespread use of the technique is hindered by the lack of sufficiently brilliant neutron sources. The Port-GISANS project addresses this problem by using nested neutron mirrors, beam shaping and focussing to increase the neutron flux. The optics preserve the lateral resolution along an interface but relaxes the resolution out-of-plane; the flux gain thus comes with a loss of depth resolution.
A device has been constructed together with the company SwissNeutronics and tested at the SANS beamline at the Delft Reactor Institute, Netherlands. The portable device can in principle be used with any SANS instrument though, including the soon-to-open SKADI beamline at ESS.
NUrF: UV-visible absorption and fluorescence spectroscopy combined with SANS
NUrF was designed as a sample environment for simultaneous access to complementary information on the structure of bulk solution samples. The set-up consists of a compact optical unit surrounding the sample holder that can be integrated into small-angle neutron scattering (SANS) instruments at different neutron sources. Quasi-simultaneous SANS, UV-visible absorption, fluorescence spectroscopy and inline density measurements are possible.
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Part of Review of Scientific Instruments, 2020