Fabrication of radiation detector using PbI2 crystal

Radiation detectors have been fabricated from lead iodide (PbI₂) 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 γ-rays from an ²⁴¹Am 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 cm²/Vs from measurement of pulse rise time for 5.48 MeV α-rays from ²⁴¹ Am. 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 about 8.4 eV for the PbI₂ crystal. A radiation detector fabricated from PbI₂ crystals grown by the Bridgman method, however, exhibited no response for γ-rays