A POLARIZED NEUTRON BEAM PRODUCED BY BRAGG REFLECTION FROM CO–FE ALLOY

Abstract
A single crystal of Co–Fe alloy is being used to produce a diffracted beam of neutrons with a flux of 2.6 × 106 n/sq. cm sec over an area of 1.5 in. by 1.5 in. This beam contains 92 ± 5% first-order neutrons (λ = 1.37 Å, E = 0.0436 ev), 3 ± 5% second- and higher-order neutrons, and 5% incoherently scattered neutrons. The first-order part of the beam has a polarization of 0.98 ±.01; the second-order part of the beam has a polarization of 0.36 ±.03 in the same direction as the first-order part, and the over-all beam has a polarization of 0.92 ±.05. The neutron spins can be reversed by the magnetic resonance technique with flipping efficiencies of 98% for the first order and 97% for the over-all beam.