Characterization of indium iodide detectors for scintillation studies

Indium iodide (InI) is a wide bandgap semiconductor (Eg = 2.0 eV) and has been investigated as an optical detector material for use in γ-ray scintillation spectroscopy. Single crystals of InI have been grown by the Bridgman process using zone-refined starting material and optical detectors have been fabricated from such crystals. The performance of these detectors has been investigated by measuring their quantum efficiency, direct X-ray detection characteristics, and electrical resistivity. The InI photodetectors have been coupled to Csl(Tl) scintillators and room-temperature energy resolutions of 7.5% (FWHM) and 9.8% (FWHM) were recorded for 662 keV and 511 keV γ-rays, respectively. Successful γ-ray detection has also been accomplished with InI photodetectors coupled to LSO (Lu2SiO5:Ce) scintillators, and a resolution of 14% (FWHM) has been recorded for 511 keV γ-rays. Finally, analysis of the electronic noise behavior of the InI detectors has been performed.