A lead-glass hodoscope calorimeter that was constructed for use in the Jefferson Lab Real Compton Scattering experiment is described. The detector provides a measurement of the coordinates and the energy of scattered photons in the GeV energy range w
ith resolutions of 5 mm and 6%/sqrt(E{gamma} [GeV]). Features of both the detector design and its performance in the high luminosity environment during the experiment are presented.
Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scatterin
g polarization transfer was analyzed at an incident photon energy of 3.7~GeV at a proton scattering angle of cma$= 70^circ$. The longitudinal transfer KLL, measured to be $0.645 pm 0.059 pm 0.048$, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is $sim$3~times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.
