~3He polarization via optical pumping in a birefringent cell

摘要

A sapphire cell was used to obtain a high ~3He nuclear polarization by means of spin-exchange optical pumping. The phase-shift difference between ordinary and extraordinary rays is well controlled using the thickness of the birefringent sapphire window so that a high circular polarization is obtained in the cell. Neutron transmission through the polarized ~3He gas was measured as a function of neutron energy. A large ~3He polarization of 63 ± 1% was obtained at a ~3He pressure of 3.1 atm. Neutron polarizations of 97 and 90% were obtained with transmission rates of 15 and 22% at 10 and 20 meV, respectively.