Results from tests on matrices of lead tungstate crystals using high energy beams

The performance of lead tungstate crystals using photomultipliers and Si avalanche photodiodes to detect the scintillation light has been studied using high energy electron, pion and muon beams at CERN. Results from tests carried out in 1993 and 1994 are presented. Good energy resolution has been obtained using photomultipliers. Some further development is required of crystals and avalanche photodiodes in order to achieve a performance, with avalanche photodiode readout, similar to that obtained using photomultipliers.