High level of $^3$He polarization of 81\% Maintained in an on-beam $^3$He spin filter using SEOP

TL;DR

This paper reports achieving and maintaining a high 3He polarization of 81% using SEOP in an on-beam spin filter, significantly improving neutron experiment efficiency and data quality.

Contribution

The study demonstrates a novel on-beam SEOP system capable of sustaining high 3He polarization levels with excellent stability, enhancing neutron scattering experiments.

Findings

Achieved 81% 3He polarization with ±2% stability.

Maintained high polarization over long periods, reducing experiment times.

Improved data quality by minimizing polarization decay effects.

Abstract

Maintaining high levels of 3He polarization over long periods of time is important to many areas of fundamental and particle beam physics. Long measurement times are often required in such experiments and the data quality is a function of the 3He polarization. This is the case for neutron scattering where the 3He can be used to analyze the spin of a scattered neutron beam and relatively small fluxes of polarized neutrons leads to experiment times longer than several days. Consequently the J\"ulich Centre for Neutron Science (JCNS) is developing spin-exchange optical pumping (SEOP) systems capable of polarizing the 3He gas in place on a typical neutron instrument. Using a polarizer device we constructed a high level of 3He polarization of 81 % \pm2% was maintained with good time stability. Such levels of polarization maintained over time will be able to reduce the measurement times for such experiments and eliminate time dependent data corrections.