Optimum thickness for He-3 neutron polarising filters

Gaseous He-3 neutron polarisers are undergoing rapid development for use wi th neutron beams. For any polarising transmission filter, polarisation incr eases and transmission decreases with increasing filter thickness. There is an optimum thickness for such fillers to minimise the errors in quantities measured in a given available time. Formulae and sample calculations are p resented for a number of important cases including the use of He-3 polarisi ng filters in conjunction with ocher types of polarisers. (C) 1999 Elsevier Science B.V. All rights reserved.