Measurement of the polarization of a pulsed electron beam with a Møller polarimeter in the coincidence mode

Abstract The Moller polarimeter at the Bates Linear Accelerator Center was used to measure the polarization of an 868-MeV electron beam with a duty cycle of 0.8%. Longitudinally polarized electrons in the beam were scattered from polarized atomic electrons in an FeCo foil, and the helicity-dependent scattering asymmetry was measured by detecting both electrons in coincidence with a pair of Cherenkov counters located symmetrically on either side of the beam. From the measured asymmetry, the beam polarization was inferred to be (42.4 ± 1.7 ± 1.2)%, where the first uncertainty is statistical and the second is systematic.