The JLab Frozen Spin Target

A polarized, frozen spin target has been designed and constructed at Jefferson Lab for use inside the CEBAF Large Acceptance Spectrometer. Protons in TEMPO-doped butanol are polarized via dynamic nuclear polarization (DNP) to approximately 90% using microwaves and an external, 5 T solenoid magnet The target sample is then cooled to approximately 30 mK while an internal 0.56 T superconducting magnet is used to maintain the polarization. Relaxation times in excess of 3S00 hours have been observed.