Prismatic platelet growth of HgI2 with organic additives

The Faile growth method, when used with purified mercuric iodide (HgI₂), along with low molecular weight polyethylene, has yielded tetragonal prismatic HgI₂ crystals. Thermal desorption-gas chromatography/mass spectroscopy (TD-GC/MS) studies reveal the existence of alkanes, alkynes, and ketones in the growth ampoules along with low molecular weight polyethylene, presumably decomposition byproducts from the polyethylene. The influence of these desorbed byproducts on the HgI₂ crystal morphology is compared to the basic Bravais-Friedel-Donnay-Harker (BFDH) crystal model. From these comparisons, it is apparent that ketones assert the most influence on the HgI₂ crystal morphology by slowing the growth of the {110} faces, thereby, causing the prismatic crystal shapes to grow. The growth method has been used to produce HgI₂ crystals with proper dimensions for room-temperature-operated Frisch collar gamma-ray spectrometers. Presently, these HgI₂ devices have yielded a best energy resolution of 1.8% at 662 keV.