A High-Field Polarized ³He Target for Jefferson Lab’s CLAS12 Spectrometer

Polarized ³He nuclear targets are invaluable surrogates for polarized neutron targets in spin-dependent scattering studies of the structure of matter. Traditional polarized ³He targets have seen steady improvements and active use over the last three decades, however they have been limited to operation in low magnetic fields. This has precluded their use in spectrometers that utilize high-magnetic-field tracking systems, such as Jefferson Lab's CLAS12 spectrometer. Developments in high-magnetic-field metastability exchange optical pumping of ³He, recently incorporated into the design of a polarized ³He ion source for RHIC and the EIC, could enable a new, polarized ³He fixed target to operate within high fields. Combining high-field techniques with the double-cell cryogenic target design used for the MIT-Bates 88-02 experiment, polarization and target density comparable to traditional polarized ³He targets could be reached while within a high magnetic field environment. We discuss the conceptual design for such a target, show our progress in this target's development, and outline plans for in-beams tests in Jefferson Lab's Hall B.