Life on board ESS

Scandinavia was highly represented at the ICNS meeting in Knoxville, Tennessee. Scandinavian scientists gave three invited talks and several (8) oral contributions, not counting many posters. In total, 30 contributions were presented by scientists affiliated in Scandinavia, which is a very large number compared to other countries, but reflects the expertise and experience of Scandinavia in the field of neutron research. Moreover, a parallel one-day workshop on neutron instrument simulation was organised by McStas experts from Copenhagen and Risø (and ILL!) where neutron scientists could get some training in instrument modeling.

This does not come as a surprise since the neutron community in Scandinavia has developed neutron science for decades through the research carried out at the facilities for neutron scattering in Denmark, Sweden and Norway.

• In Denmark, Risø National Laboratory (now Risø DTU) has an outstanding international reputation in neutron diffraction and neutron scattering research and has been developed over the years thanks to their reactor-based neutron facility. Risø has had a seminal role in neutron methods and has had an impact on all neutron instruments. All the expertise acquired there has been passed on to other neutron centres in the world, in particular SINQ at PSI, Switzerland, where Danish scientists are operating several instruments.
• In Sweden, scientists are using neutron scattering methods in soft condensed matter, in physics and chemistry in engineering sciences; they work at the ILL, Grenoble, at ISIS in UK, at PSI in Switzerland, but also in Germany. In Sweden, experiments were performed at the Swedish research reactor R2 in Studsvik. The NFL - Studsvik Neutron Research Laboratory was a leading institute for neutron sciences. As a company, Studsvik operates not only in Sweden, but also in UK, Germany or USA and has a further company segment for Global Services.
• In Norway, the research reactor JEEP II at Kjeller (Institute for Energy Technology, IFE, near Oslo) is a national resource for material physics research and neutron irradiation technology. The availability of this multi-purpose reactor is kept very high to content the many user-groups.

All these centres have joined forces to develop modeling tools to optimise various neutron instruments, which explains why the Copenhagen / Roskilde group is acquired such high repute in neutron instrument modeling and virtual experiments run on computers.

As a complement to the international organisation now being built up by ESS Scandinavia for designing and developing the accelerator driven, next generation neutron source in Sweden; the 273 neutron users in Scandinavia will provide us with a solid base of supporting expertise right in the neighbourhoods of Lund!

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The closing address to ICNS was given by a lyrical Sunil Sinha, in great form. Sunil reviewed the impact of neutron scattering methods on major fields of science, stressing the uniqueness of neutrons but also the complementarity with synchrotron x-rays. He said, and he was absolutely right, that modern neutron sources sit next to synchrotron x-rays sources. This is why ESS will be built next to the MAX IV synchrotron!

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I'm walking around the booths at the ICNS exhibition center where ESS Scandinavia is represented in Knoxville, Tennessee. There seems to be a concern here on the value of neutron methods and the impact of neutron scattering in science. This is quite a serious point at a time when the ESS is being debated. In Europe, we (neutron centres) have made some efforts to reach out towards the general public.

The ILL has produced wonderful brochures of which I've been the editor. ESS Scandinavia has also done a great job with the "Neutrons & Health" booklet where we explain how neutron science amongst other things can help us understand living processes, the motion of molecules in a cell, seeing the proteins more clearly and develop drug design etc. We are also preparing a new booklet on "Neutrons for Society/Neutrons for Science" - a real must for all of you who would like to understand more about neutron scattering, how it develops materials science and benefits mankind through research!

I feel that it is up to the neutron centres to tackle the impact question regarding the value of neutron scattering in scinence by themselves. They should not wait for someone else to do the job. ESS Scandinavia is committed to promote and increase the awareness of neutron science in society, develop the research community and strengthening the interaction between x-ray users and and neutron users.

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Neutrons and x-rays probe properties of particles which are the basic components of matter and complement each other nicely. They form radiations with similar wavelength ranges in the nanometer range, however x-rays are sensitive to charged particles, in particular electrons in atoms, while neutrons interact with massive particles such as atom nuclei and possess a magnetic moment which makes them like a microscopic compass.

X-rays are said to be electronic while neutrons are magnetic!

A major difference between neutrons and x-rays arises from sources to produce them. Synchrotron x-ray sources are very bright and focussed: they produce narrow parallel beams of x-rays with high degree of monochromaticity. Neutron sources are big, unfocussed and lead to neutron beams which are at least 10-12 orders magnitude less bright than x-ray beams!

However, neutrons are unique and are needed for their applications in magnetism, in studies of liquids, polymers, soft matter and biology because neutrons easily locate hydrogen atoms.

The obvious strategy for scientists is to use both x-ray and neutrons. With x-rays, they observe static atomic arrangements and detect electronic properties. With neutrons, a very gentle probe, scientists observe motions of atoms, arrangement and dynamics of magnetic moments in materials, and determine bio-active centres in biological macromolecules or proteins.

More intense neutron beams are needed!

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