A frozen spin polarized target, constructed at Jefferson Lab for use inside a large acceptance spectrometer, is described. The target has been utilized for photoproduction measurements with polarized tagged photons of both longitudinal and circular polarization. Protons in TEMPO-doped butanol were dynamically polarized to approximately 90% outside the spectrometer at 5 T and 200--300 mK. Photoproduction data were acquired with the target inside the spectrometer at a frozen-spin temperature of approximately 30 mK with the polarization maintained by a thin, superconducting coil installed inside the target cryostat. A 0.56 T solenoid was used for longitudinal target polarization and a 0.50 T dipole for transverse polarization. Spin-lattice relaxation times as high as 4000 hours were observed. We also report polarization results for deuterated propanediol doped with the trityl radical OX063.
@article{arxiv.1204.1250,
title = {The Jefferson Lab Frozen Spin Target},
author = {C. D. Keith and J. Brock and C. Carlin and S. A. Comer and D. Kashy and J. McAndrew and D. G. Meekins and E. Pasyuk and J. J Pierce and M. L. Seely},
journal= {arXiv preprint arXiv:1204.1250},
year = {2015}
}
Comments
11 pages, 12 figures, preprint submitted to Nuclear Instruments and Methods in Physics Research, Section A