Measurements and simulations of Cherenkov light in lead fluoride crystals

The anticipated use of more than 1000 lead fluoride (PbF2) crystals as a fa st and compact Cherenkov calorimeter material in a parity violation experim ent at MAMI stimulated the investigation of the light yield (LY) of these c rystals. The number of photoelectrons (p.e.) per MeV deposited energy has b een determined with a hybrid photomultiplier tube (HPMT). In response to ra dioactive sources a LY between 1.7 and 1.9 p.e./MeV was measured with 4% st atistical and 5% systematic error. The LY optimization with appropriate wra ppings and couplings was investigated by means of the HPMT. Furthermore, a fast Monte Carlo simulation based on the GEANT code was employed to calcula te the characteristics of Cherenkov light in the PbF2 crystals. The computi ng time was reduced by a factor of 50 compared to the regular photon tracki ng method by implementing detection probabilities as: a three-dimensional l ook-up table. For a single crystal a LY of 2.1 p.e./MeV was calculated. The corresponding detector response to electrons between 10 and 1000 MeV was h ighly linear with a variation smaller than 1%. (C) 2001 Elsevier Science B. V. All rights reserved.