Generic guide concepts for the European Spallation Source
2015 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 803, 89-99 p.Article in journal (Refereed) Published
The construction of the European Spoliation Source (ESS) faces many challenges from the neutron beam transport point of view: the spoliation source is specified as being driven by a 5 MW beam of protons, each with 2 GeV energy, and yet the requirements in instrument background suppression relative to measured signal vary between 10(-6) and 10(-8). The energetic particles, particularly above 20 MeV, which are expected to be produced in abundance in the target, have to be filtered in order to make the beamlines safe, operational and provide good quality measurements with low background. We present generic neutron guides of short and medium length instruments which are optimised for good performance at minimal cost. Direct line of sight to the source is avoided twice, with either the first point out of line of sight or both being inside the bunker (20 m) to minimise shielding costs. These guide geometries are regarded as a baseline to define standards for instruments to be constructed at ESS. They are used to find commonalities and develop principles and solutions for common problems. Lastly, we report the impact of employing the over-illumination concept to mitigate losses from random misalignment passively, and that over-illumination should be used sparingly in key locations to be effective. For more widespread alignment issues, a more direct, active approach is likely to be needed.
Place, publisher, year, edition, pages
2015. Vol. 803, 89-99 p.
Neutron guides, Neutron scattering instrumentation, Misalignment, European spoliation source, VITESS, Monte Carlo simulation
IdentifiersURN: urn:nbn:se:uu:diva-267644DOI: 10.1016/j.nima.2015.09.035ISI: 000363464600013OAI: oai:DiVA.org:uu-267644DiVA: diva2:874501