Neutron guide system for small-angle neutron scattering instruments of the Jülich Centre for Neutron Science at the FRM-II

Following the shut-down of the FRJ-2 research reactor in Jülich a large part of the neutron scattering instrumentation operating there is currently being moved to the FRM-II research reactor in Garching-München. The installation of these instruments requires the design and set-up of new neutron guides with geometrical and optical features imposed by the positioning of the instruments in the neutron guide hall and by the foreseen significant improvement of the instrument performance. Particularly three SANS diffractometers require a special approach due to on one hand, their pre-determined size and on the other hand, the demanded neutron wavelength range. Expected characteristics of three neutron guides (currently under construction) optimized using VITESS and McStas simulation packages, namely the vertically “S-shaped” guides serving the KWS2 and KWS1 conventional SANS instruments and the horizontally “S-shaped” guide serving the focusing KWS3 instrument, will be reported on.