A highly polarized hydrogen/deuterium internal gas target embedded in a toroidal magnetic spectrometer
Cheever, D × Ihloff, E Kelsey, J Kolster, Hauke Meitanis, N Milner, R Shinozaki, A Tsentalovich, E Zwart, T Ziskin, V Xiao, Y Zhang, C #
Elsevier science bv
Nuclear instruments & methods in physics research section a-accelerators spectrometers detectors and associated equipment vol:556 issue:2 pages:410-420
A polarized hydrogen/deuterium internal gas target has been constructed and operated at the internal target region of the South Hall Ring (SHR) of the MIT-Bates Linear Accelerator Center to carry out measurements of spin-dependent electron scattering at 850 MeV. The target used an Atomic Beam Source (ABS) to inject a flux of highly polarized atoms into a thin-walled, coated storage cell. The polarization of the electron beam was determined using a Compton laser backscattering polarimeter. The target polarization was determined using well-known nuclear reactions. The ABS and storage cell were embedded in the Bates Large Acceptance Toroidal Spectrometer (BLAST), which was used to detect scattered particles from the electron-target interactions. The target has been designed to rapidly (similar to 8h) switch operation from hydrogen to deuterium. Further, this target was the first to be operated inside a magnetic spectrometer in the presence of a magnetic field exceeding 2 kG. An ABS intensity 2.5 x 10(16) at/s and a high polarization (approximate to 70%) inside the storage cell have been achieved. The details of the target design and construction are described here and the performance over an 18 month period is reported. (c) 2005 Elsevier B.V. All rights reserved.