Vector analysis of polarization at small-angle neutron scattering

The three-dimensional (3-D) analysis in small-angle polarized neutron scatt ering (SAPNS) is presented, and the corresponding experimental device is de scribed. The peculiar properties of 3-D analysis allows (i) to investigate critical scattering in iron at energy transfer omega similar to 1-50 mu eV where direct measurement of the magnetic scattering is impossible, (ii) to determine the correlation length of the critical fluctuation very close to the Curie temperature where in the case of the conventional critical scatte ring the inelasticity and multiple scattering spoil the results. (C) 2001 E lsevier Science B.V. All rights reserved.