Heat treating and detectors characterization of α-HgI₂

α-HgI₂ crystal was grown using a static sublimation method in a self-designed vertical two-zone growth furnace. After 23 days growth, a single crystal of about 15 mm × 12 mm × 5 mm was obtained. The as-grown crystal was characterized by means of XRD and 4155 CVIV instrument, and the performance of the detector made with the as-grown HgI₂ crystal was tested. The results indicate that excess iodine exists in the as-grown crystal, which can be removed effectively by heating at a feasible temperature. The resistivity of the as-grown crystal is about 10¹² Ω · cm. The spectroscopy response to gamma ray (an uncollimated ²⁴¹Am radiative source with the principal energy of 59.5 keV) of the detectors shows that the energy resolution is 14.6% corresponding to FWHM ≈ 8.69 keV at room temperature.