Development of 3 He Polarized Neutron Spin Filters at KENS

Abstract

We report on progress of the development of neutron spin filters based on polarized gaseous ³He at KENS (Neutron Science Laboratory, KEK). ³He polarizer cells made of quartz glass and sapphire are prepared and tested. Quartz glass cells with spin relaxation times of more than 100 h are routinely produced. A ³He polarization of 63% has been achieved with a sapphire cell of a ³He pressure of 3 atm, and with this ³He cell, a neutron polarization of about 86% was obtained at thermal energy.