Journal Article

A High-Density Polarized 3He Gas–Jet Target for Laser–Plasma Applications

Swaczyna, Robert, Giesen, Ulrich, Kannis, Chrysovalantis, Feilbach, Herbert, Pfeifer, Heinz, Pfennings, Johannes, Soltner, Helmut, Fedorets, Pavel, Klehr, Franz, Engin, Ilhan, Büscher, Markus, Schneider, Claus Michael, Engels, Ralf, Schnitzler, Norbert, Glückler, Harald, Zheng, Chuan, Lennartz, Manfred

2022

Overview

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 1019 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.

• Publisher: MDPI AG
• Subject: Coils / Compressed gas / Density / Energy / Experiments / Gas jets / gas-jet target / hyperpolarized 3He / Lasers / laser–plasma acceleration / Magnetic fields / Nuclear fusion / phelix laser / Plasma / Polarization / polarized ion beams