2019 Workshop on Polarized Sources, Targets, and Polarimetry

Magnetic Field Requirements for the CLAS12 Polarized Target

23 Sept 2019, 11:00

20m

Downtown Holiday Inn

Solid Polarized Targets Solid Polarized Targets

Speaker

Victoria Lagerquist (Old Dominion University, Jefferson Lab)

Description

Upcoming spin structure experiments in Hall B at Jefferson Lab will employ a new dynamically polarized target inside the CLAS12 detector system. Protons and deuterons in irradiated NH₃ and ND₃ will be polarized at 1 K using the 5 T field of the CLAS12 solenoidal magnet. For optimum polarization, the field uniformity requirements are around 100 ppm over the volume of the 12 cm³ target sample. I will present field map results for the solenoid, and discuss methods to improve the uniformity utilizing thin superconducting shim coils integrated within the 1 K refrigerator. I will also demonstrate that this method to adjust the 5 T field also enables the simultaneous opposite polarization of two adjacent target cells.

Presentation materials

Lagerquist PSTP 2019.pdf