Abstract
Neutrons are an essential tool for science and industry for probing the structure and dynamics ofmatter from the mesoscale to the picoscale and from seconds to femtoseconds. In Europe research,industry and society benet from a globally unique environment of various neutron sources withthe agship facilities ILL in Grenoble, France, and ESS in Lund, Sweden. The latter is currently underconstruction and will represent the world’s most powerful neutron facility. The unique capabilities ofneutrons and the European neutron infrastructure have been highlighted in reports by the EuropeanNeutron Scattering Association (ENSA) and the ESFRI Neutron Landscape Group recently. More than8000 users utilize the available neutron sources in Europe, requesting nearly twice the availablecapacity oered per year. This high demand for research with neutrons is managed by peer reviewprocesses established to permit access to the facilities resulting in a highly competitive situation whichsometimes hampers access by well-qualied applicants.The main processes to release neutrons from atomic nuclei are: (i) ssion in nuclear reactors, (ii)spallation using high-power proton accelerators, and (iii) nuclear reactions induced by low-energyprotons or deuterons. The rst two techniques are used very successfully in Europe and oer thehighest neutron source strength with versatile options.In view of the continuously high demand for neutron experiments by science and industry and thephasing out of existing reactor-based neutron facilities in Europe in the near future, new solutions andstrategies are required to provide sustainable and eective access to neutrons in Europe. New neutroninfrastructures have to provide novel capabilities not oered by the present-day facilities based onthe ageing suite of research reactors in Europe. Enhanced performance does not necessarily rely onincreased source strength, which goes hand-in-hand with cost increase, but can include improvedexibility and accessibility, specialization on particular important societal challenges or optimizationon brilliance for small beams. In particular, cost-eective solutions are required to compensate thepotential capacity loss and complement high-ux sources such as the new ESS spallation neutronsource.The High Brilliance neutron Source (HBS) project will demonstrate the technical and operational conceptfor a neutron infrastructure based on a low-energy proton accelerator. HBS is designed as avery exible neutron infrastructure with neutron beams optimized for brilliance. It will host a full suiteof highly competitive instruments. Thus HBS will be capable to serve as a national or regional highlyattractive neutron research centre. The HBS source will benet of state-of-the-art accelerator technology,combined with unique target-moderator concepts. HBS will mark a change in paradigm forresearch with neutrons where every individual neutron instrument will have its own neutron sourcewith optimized pulse structure and a moderator adapted to the specic requirements of the instrument.Thus it will provide a unique and attractive option for achieving optimum and ecient brilliancefor all neutron experiments at a lower cost compared to present-day large-scale neutron facilities.
