The 3He polarizing filter on the neutron reflectometer D17

The D 17 neutron reflectometer at the Institut Laue-Langevin, Grenoble, can now carry out neutron polarization analysis experiments with a polarized He-3 gas filter. The cell containing the gas is housed in the evacuated detector tank. The gas polarization decays with time and must be replenished periodically. A novel method to accomplish this in situ, known as local filling, has been developed to minimize down-time on the instrument. The instrument is now optimized for the rapid collection of off-specular scattering with polarization analysis, complementary to a polarizing supermirror analyser which is used for measurements of specular reflectivity. Cell performance, test and experimental data are presented, along with methods for analysing the data collected using the filter. (c) 2006 Elsevier B.V. All rights reserved.