The Effects of Dislocations and Crystal Defects on the Energy Resolution and Response Uniformity of Mercuric Iodide Detectors

The energy resolution and response uniformity of HgI2 detectors to nuclear radiation depends strongly on dislocation density and distribution in the HgI2 crystal bulk. Several large planar detectors fabricated from the interiors of large single crystals verified this dependence. Scanning with collimated low-energy (6 keV) and medium-energy (60 keV) gamma-rays confirmed the association of poor resolution and counting efficiency with regions of high dislocation density and crystal imperfection.