Diffusive Transfer of Polarized 3He Gas through Depolarizing Magnetic Gradients

TL;DR

This study investigates how polarized 3He gas diffuses through magnetic field gradients, assessing depolarization effects to improve polarized ion sources for accelerators.

Contribution

The paper presents experimental measurements of 3He spin relaxation during diffusion across magnetic gradients, providing insights into depolarization mechanisms.

Findings

Depolarization increases with transverse magnetic field gradients.

Measurement technique infers polarization transfer between cells.

Results inform design of polarized 3He sources for accelerators.

Abstract

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.