FABRICATION OF RADIATION DETECTOR USING PBI2 CRYSTAL

Radiation detectors have been fabricated from lead iodide (PbI2) cryst als grown by two methods: zone melting and Bridgman methods. In respon se characteristics of the detector fabricated from crystals grown by t he zone melting method, a photopeak for gamma-rays from an Am-241 sour ce (59.5 keV) has been clearly observed with applied detector bias of 500 V at room temperature. The hole drift mobility is estimated to be about 5.5 cm(2)/Vs from measurement of pulse rise time for 5.48 MeV al pha-rays from Am-241. By comparing the detector bias versus saturated peak position of the PbI2 detector with that of the CdTe detector, the average energy for producing electron-hole pairs is estimated to be a bout 8.4 eV for the PbI2 crystal. A radiation detector fabricated from PbI2 crystals grown by the Bridgman method, however, exhibited no res ponse for gamma-rays.