Conceptual Design of a Polarized 3He Target for the CLAS12 Spectrometer

TL;DR

This paper proposes a conceptual design for a polarized helium-3 target for the CLAS12 spectrometer, utilizing advanced optical pumping to achieve high polarization and target density for improved experimental luminosity.

Contribution

It introduces a novel two-cell polarized helium-3 target design optimized for the CLAS12 spectrometer, leveraging high-field optical pumping techniques for enhanced polarization.

Findings

Achieves 60% helium-3 polarization in the target cell.

Provides a target thickness suitable for maximum luminosity at 2.5 μA beam current.

Design supports the experimental requirements of the CLAS12 spectrometer.

Abstract

We present a conceptual design for a polarized $^3$He target for Jefferson Lab's CLAS12 spectrometer in its standard configuration. This two-cell target will take advantage of advancements in optical pumping techniques at high magnetic field to create 60\% longitudinally polarized $^3$He gas in a pumping cell inside the CLAS12 5 T solenoid. By transferring this gas to a 20 cm long, 5 K target cell, a target thickness of $3 \times 10^{21}$ $^3$He/cm$^2$ will be produced, reaching the detector's specified maximum luminosity with a beam current of 2.5 $\mu A$.