New features of the long-wavelength polarisation analysis spectrometer - LONGPOL

Recent improvements in the performance of the long-wavelength polarisation analysis (PA) spectrometer (LONGPOL) at Australian Nuclear Science and Technology Organisation will be presented. By combining neutron PA and time-of-flight (TOF) energy analysis, LONGPOL can be used to simultaneously detect changes in momentum, polarisation and energy of the neutrons after interaction with the sample. The instrument now uses supermirror devices to polarise and analyse the neutron beam in the eight detectors with similar to95% polarisation efficiency. Preliminary analysis of the spectrum of a magnetic diffuse feature from a Mn90Cu10 crystal by the maximum entropy method indicates energy resolution of similar to20 mueV. The instrument is now resuming scientific use and PA experiments are being planned with energy analysis in the future with a view to transfer this capability for simultaneous polarisation and energy analysis to Australia's replacement research reactor. (C) 2003 Elsevier Science B.V. All rights reserved.