Swedness is a SSF sponsored graduate school in neutron scattering (www.swedness.se) which was launched in early 2017. The intention of the SwedNess initiative is to increase the number of users for neutron scattering and to strengthen expertise within this area in Sweden. This is important in light of the European Spallation Source (ESS, www.europeanspallationsource.se) which is currently being built in Lund.
Neutrons have both particle-like and wave-like properties. They do not possess a charge but a spin, which makes them carriers of a magnetic moment. Neutrons are produced either through fission at reactor sources (as at the ILL in Grenoble) or through spallation in an accelerator-based pulsed source (such as the ISIS facility in the UK). Scattering of neutrons with matter allows the study of arrangements and dynamics of atoms and molecules in materials over an enormous range of distances and times. Combined, the various methods of neutron scattering (like diffraction, inelastic and quasielastic scattering, small angle scattering, tomography, reflectometry and surface scattering) are capable of extracting very subtle information about the properties and behavior of many different materials and systems. Due to recent technological developments, the ESS will provide the community with unique capabilities. The ESS will represent the strongest neutron source in the world and will be offering novel instrumentation.
SwedNess is set up as a collaborative effort between six Swedish universities: Uppsala, Chalmers, KTH, Linköping, Lund, and Stockholm. During the first half of the year 2017 20 PhD students PhD were recruited to the school. During their project and through the curriculum of SwedNess, these students will be extensively and intensively trained in neutron scattering, to become specialist users in several neutron techniques.
SU hosts three SwedNess students, two at MMK and one at DBB. The picture below shows the three students at the first annual meeting – which was held in Gothenburg April 23 – 25, 2018 – presenting their first results in the poster session. From left to right: Stefanie Siebeneichler (MMK), Marie Lycksell (DBB), Paulo Barros (MMK).
Maria Lycksell who is supervised by Erik Lindahl researches on membrane protein-lipid complexes and combines in her research molecular dynamics simulations with small angle neutron scattering (SANS) experiments to study the dynamic interactions between membrane proteins and the surrounding lipid bilayer. These interactions are key for many functions, such as ligand-gated ion channels. SANS provides structural data at room temperature where the interaction and dynamics of the complex is realistic, however the data only give low-resolution information. Combining experiments with molecular simulations of membrane protein complexes can allow the development of high-resolution accurate lipid structure and dynamics at room temperature, which is important both in fundamental biochemistry and drug design applications.
Paulo Barros who is supervised by Ulrich Häussermann, investigates the behavior of clathrate hydrates at extreme (high pressure and low temperature) conditions by neutron diffraction and inelastic neutron scattering experiments. Clathrate hydrates are inclusion compounds in which water forms a host with polyhedral cages that enclose small concentrations of guest molecules M. Clathrate hydrates occur widely in nature with M e.g. CH4 and CO2 and have important environmental implications. For example, it is expected that global warming will set free tremendous amounts of the greenhouse gas methane, currently stored as clathrate hydrate in the permafrost. Neutron scattering is highly sensitive to hydrogen and can reveal even small changes in hydrogen-bonded networks. Understanding the stability and transitions of clathrate hydrates at extreme conditions relates to understanding their potential environmental impact.
Stefanie Siebeneichler, who is supervised by Anja-Verena Mudring, focuses on the characterization of the magnetic properties of complex materials such as inorganic transition metal phosphate open framework structures. These materials often combine magnetism with a second property, like ion conduction or luminescence. The connectivity of the transition metal polyhedra controls via superexchange directly the magnetic behaviour. The topologies of these network structures frequently give rise to spin frustrations and complex, new, magnetic behaviour. Since neutrons carry a spin they can act as tiny magnets. This can be exploited to extract the magnetic structure of a material in neutron diffraction experiments.