Construction and Beam Test of a Small

Abstract

A compact homogenous electromagnetic calorimeter with an energy resolution of better than 5%= E=GeV , made out of lanthanum doped lead tungstate crystals from Bogoroditsk, Russia, has been built for use in the ZEUS detector. The whole calorimeter, composed of 4x4 crystals, each of dimensions 23.823.8200 mm , light guides and photomultipliers, ts into a space of 121227 cm . Beam tests with electrons up to 100 GeV showed an energy resolution of better than 4:9%= E=GeV , a linearity of better than 1% and a position resolution of 1.1 mm. The inuence of temperature variations and recovery of an irradiated crystal on the total energy signal could be corrected to better than 1%. EGS4 simulations reproduce the results very well