Production of a partially polarised 4.56 MeV neutron beam using the associated particle method

Abstract

The associated particle technique was used with the D(d,n) 3He reaction to produce a highly collimated partially polarised 4.56 MeV neutron beam. A coincidence time resolution of 5 ns was obtained by using dual parameter pulse height analysis to correct for the kinematic variations in flight times of the 3He particles. A rotating self-supporting thin film deuterated polyethylene target was used to reduce problems caused by elastically scattered deuterons from the target. A neutron beam intensity of 70 neutrons/sec· msterad was obtained at a deuteron bombarding beam current of 1.5 μA. The background count rate outside the neutron beam solid angle corresponded to a neutron flux of intensity 10 −4 of that in the collimated beam. This beam to background ratio is high enough to allow the use of this method in small angle scattering experiments.