Fabrication of radiation detector using PbI/sub 2/ crystal

Radiation detectors have been fabricated from lead iodide (PbI/sub 2/) crystals grown by two methods: zone melting and Bridgman methods. In response characteristics of the detector fabricated from crystals grown by the zone melting method, a photopeak for /spl gamma/-rays from an /sup 241/Am source (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/sup 2//Vs from measurement of pulse rise time for 5.48 MeV /spl alpha/-rays from /sup 241/Am. By comparing the detector bias versus saturated peak position of the PbI/sub 2/ detector with that of the CdTe detector, the average energy for producing electron-hole pairs is estimated to be about 8.4 eV for the PbI/sub 2/ crystal. A radiation detector fabricated from PbI/sub 2/ crystals grown by the Bridgman method, however, exhibited no response for /spl gamma/-rays.<
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