Bismuth iodide (III) crystals for nuclear radiation detectors

Bismuth tri-iodide (BiI/sub 3/) is an attractive material for room temperature radiation detectors because of its wide bandgap energy and high photon stopping power. In this study, BiI/sub 3/ crystals have been grown by the vertical Bridgman technique using commercially available powder. The grown crystals have been characterized in terms of their structural properties and stoichiometry. Room temperature radiation detectors have been fabricated from the crystals and tested by measuring their leakage currents and spectroscopic responses. A clear peak corresponding to 5.48 MeV /spl alpha/-particles (/sup 241/Am) was recorded with a BiI/sub 3/ detector 82 /spl mu/m thick with 0.8 mm/sup 2/ palladium electrodes. The energy resolution of the 5.48 MeV peak was measured to be 2.2 MeV FWHM.