Diffusive transfer of polarized ³He gas through depolarizing magnetic gradients

Transfer of polarized ³He gas across spatially varying magnetic fields will facilitate a new source of polarized ³He ions for particle accelerators. In this context, depolarization of atoms as they pass through regions of significant transverse field gradients is a major concern. To understand these depolarization effects, we have built a system consisting of a Helmholtz coil pair and a solenoid, both with central magnetic fields of order 30 gauss. The atoms are polarized via metastability exchange optical pumping in the Helmholtz coil and are in diffusive contact via a glass tube with a second test cell in the solenoid. We have carried out measurements of the spin relaxation during transfer of polarization in ³He at 1 torr by diffusion. We explore the use of measurements of the loss of polarization taken in one cell to infer the polarization in the other cell