A high-density polarized 3He gas-jet target for laser-plasma applications

TL;DR

This paper presents a high-density polarized helium-3 gas-jet target designed for laser-plasma applications, enabling precise positioning and stable polarization for nuclear physics experiments.

Contribution

The paper introduces a novel high-density polarized 3He gas-jet target with a 3D adjustment system and auxiliary gas system for improved stability and control in laser-plasma experiments.

Findings

Achieved gas jet densities of about 10^19 cm^-3

Demonstrated precise 3D positioning of the jet

First experimental results showing stable polarization

Abstract

A laser-driven spin-polarized 3He2+ beam source for nuclear-physics experiments and for the investigation of polarized nuclear fusion demands a high-density polarized 3He gas-jet target. Such a target requires a magnetic system providing a permanent homogeneous holding field for the nuclear spins plus a set of coils for adjusting the orientation of the polarization. Starting from a transport vessel at a maximum pressure of 3 bar, the helium gas is compressed for a short time and can be injected into a laser-interaction chamber through a non-magnetic opening valve and nozzle, thus forming jets with densities of about a few 10^19 cm-3 and widths of about 1 mm. The target comprises a 3D adjustment system for precise positioning of the jet relative to the laser focus. An auxiliary gas system provides remote target operation and flushing of the gas lines with Ar gas, which helps to reduce polarization losses. The design of the target, its operation procedures and first experimental results are presented.