2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/87923The capability of performing accurate measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically-pumped polarized 3He spin filter and a relative transmission measurement technique. 3He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method.35 pages, 11 figures, LaTeX format, submitted to Phys. Rev. A (1999)Instrumentation and Detectorstext