He-3 polarization via optical pumping in a birefringent cell

A sapphire cell was used to obtain a high He-3 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 He-3 gas was measured as a function of neutron energy. A large He-3 polarization of 63 +/- 1% was obtained at a He-3 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. (c) 2005 American Institute of Physics