Study of Imperfections in Mercury Iodide by the Thermally Stimulated Currents Method

Thermally stimulated current and nuclear measurements are reported for HgI2 crystals. The energy of the imperfections is determine from the initial rise of the TSC current for each of the imperfections observed in this measurement. The different structures are isolated by using the thermal cleaning method. The retrapping mode, whether fast or slow, had been deternined by comparing the initial rise energy to the Bube and Grossweiner´s energies which apply to fast and slow retrapping centers respectively. For slow retrapping centers the capture cross section and the detrapping times are calculated whereas for fast retrapping centers the product of imperfection concentration and carrier life time is computed. Using this approach an effort is made to identify the imperfections which particularly affect the operation of nuclear detectors made of this crystal. In the present crystal we find two such levels.