Reduction of Polarization in Mercuric Iodide Nuclear Radiation Detectors

The majority of HgI2 detectors which have an energy resolution less than 5% for 241Am do not have severe plarization effects at all. Polarization effects are reported for detectors having energy resolution greater than 5% for 241Am in an attempt to discover if polarization is mainly due to either a nonoptimal fabrication or to severe trapping in the bulk crystalline material. An improved fabrication procedure using a rapid etch and evaporated palladium contacts is reported. This procedure has produced polarization free detectors which were refabricated from detectors which previously showed polarization.