Gadolinium iodide doped with Cerium (GdI3:2%Ce) and undoped gadolinium iodide (GdI3) crystals were grown by vertical Bridgman method with sealed quartz crucible. Crystal ingots with dimension of phi 15 mmx20 mm were cut and polished to be plates of 12 mmx10 mmx2.5 mm and 11 mmx8 mmx2.5 mm. GdI3:2%Ce without crack and inclusion were encapsulated for all the measurements. X-ray diffraction analysis shows that the Ce3+-doped GdI3 and undoped GdI3 crystal have the same structure. X-ray and ultraviolet excited luminescence spectra of GdI3:2%Ce present broad emission bands peaking at 520 nm and 550 mu, respectively, which correspond to 5d-4f transition luminescence of Ce3+. Three peaks located at 262, 335 and 440 nm can be observed in excitation spectra when photoluminescence is monitored at 550 nm. The GdI3:2%Ce crystal presents an excellent energy resolution of 3.4% and decay time of (58 +/- 3) ns under excitation of 662 keV gamma-rays from Cs-137 source. The results show the GdI3:2%Ce crystal is a promising scintillator for gamma ray and neutron detection.
