OSIRIS: the polarisation analysis spectrometer and diffractometer at ISIS

Methodologies for polarised neutron scattering on pulsed sources are under development at ISIS using the new instrument OSIRIS. The first operative op tion is a high-intensity high-resolution Delta d/d similar to 2.4 x 10(-3) powder diffraction detector in near-backscattering geometry, which is now o perational. We present the instrument and examples of recent experiments. T he elastic option will be followed by the inelastic, where a multiple cryst al analyser and associated detectors in near-backscattering geometry will p rovide polarisation analysis with an estimated energy resolution of Delta E similar to 25 mu eV. This part is currently being built, and is expected t o be completed within little more than a year. (C) 2000 Elsevier Science B. V. All rights reserved.