A study on the use of lead fluoride for electromagnetic calorimetry

The properties of lead fluoride as a Cerenkov material for use in electromagnetic calorimetry were studied. A prototype calorimeter module consisting of a 5*5 array of 2.1-cm*2.1-cm*18.5-cm crystals was built and tested in a test beam. Results are given on energy resolution, shower size, and e/ pi separation for electrons and pions in the range of 1-4 GeV. The light output was found to give >or=1000 photoelectrons per MeV in good quality crystals and to provide useful signals down to as low as 32 MeV. Measurements were made on radiation damage in lead fluoride using /sup 60/Co gamma rays and high energy ionizing particles, as well as on thermoluminescence after irradiation. It was found that only modest damage occurs up to a level of approximately 30 krad in large, calorimeter size crystals, and that the damage can be easily removed by optical bleaching.< >