A photon calorimeter using lead tungstate crystals for the CEBAF Hall A Compton polarimeter

Abstract A new Compton polarimeter is built on the CEBAF Hall A electron beam line. Performances of 10% resolution and 1% calibration are required for the photon calorimeter of this polarimeter. This calorimeter is built with lead tungstate scintillators coming from the CMS electromagnetic calorimeter R&D. Beam tests of this detector have been made using the tagged photon beam line at MAMI, Mainz, and a resolution of 1.76%⊕2.75%/ E ⊕0.41%/E has been measured.