Trace element and hydrocarbon analysis of mercuric iodide by ion microprobe and electron induced x-ray fluorescence techniques

Since 1971, research on mercuric iodide (HgI2) crystals as nuclear radiation detectors has generated a growing interest in the semiconductor and crystalline properties of this material. An investigation pursued only recently pertains to the trace element and hydrocarbon impurities present in the raw HgI2 starting material. While various purifying schemes have been employed, there is only a very limited understanding of their effectiveness. This paper describes studies undertaken with ion microprobe and electron x-ray fluorescence techniques (1) to quantify the trace elements in the residues removed from the starting material as well as in the final single crystals, and (2) to show the influence of impurity removal on nuclear detector performance. Both elemental and hydrocarbon contamination have been identified. The results indicate a preferred method of purification of the HgI2 growth material