• M. Farkhondeh, dc. Cheever, W.A. Franklin, E. Ihloff, B. McAllister, R. Milner, W. North, C. Tschalaer, E. Tsentalovich, D. Wang, D. Wang, F. Wang, A. Zolfaghari, T. Zwart, J. van der Laan
  MIT, Middleton, Massachusetts

The MIT Bates Accelerator Center is delivering highly polarized electron beams to its South Hall Ring for use in Nuclear Physics Experiments. Circulating electron currents in excess of 200 mA with polarization of 70% are scattered from a highly polarized, but very thin atomic beam source deuterium target. At the electron source a compact diode laser creates photoemission of quasi-CW mA pulses of polarized electrons at low duty factors from a strained GaAs photocathode. Refurbished RF transmitters provide power to the 2856 MHz linac, accelerating the beam to 850 MeV in two passes before injection into the South Hall Ring. In the ring a Siberian snake serves to maintain a high degree of longitudinal polarization at the BLAST scattering target. A Compton laser back-scattering polarimeter measures the electron beam polarization with a statistical acuracy of 6% every 15 minutes.