Measurement of $^3$He$^{++}$ Polarization at 5.3 MeV via Scattering with an Unpolarized $^4$He Target

TL;DR

This paper discusses the development of a polarized helium-3 ion source for RHIC, focusing on measuring the polarization of helium-3 ions via scattering with an unpolarized helium-4 target, a key step for future experiments.

Contribution

It introduces a novel method to measure helium-3 polarization using scattering with helium-4, advancing the development of polarized ion sources for collider applications.

Findings

Concept for polarization measurement developed in 2014.

Progress made in ion source development and polarimeter construction.

Expected demonstration experiment in the coming years.

Abstract

Since 2012, a BNL-MIT collaboration has worked to develop a polarized $^3$He ion source for the Relativistic Heavy Ion Collider (RHIC) using the existing Electron Beam Ionization Source (EBIS). $^3$He atoms are polarized using optical pumping at high field and injected as neutral atoms into the EBIS. A critical issue is the demonstration that the polarization of the extracted $^3$He$^{++}$ ions from the source is high. In 2014, a concept to measure the nuclear polarization was developed in this paper. Since then, the development of the polarized $^3$He ion source has progressed, the polarimeter is under construction, and the demonstration experiment is expected to take place in the next several years.