Instrument Development and Gamma Spectroscopy With Strontium Iodide

Development of the Europium-doped Strontium Iodide scintillator, SrI 2 (Eu), involves advances in crystal growth, optics and readout methodology for prototype detectors. We have demonstrated energy resolution of 3% at 662 keV for a 26 cm 3 SrI 2 (Eu) crystal, which is equivalent to the performance obtained with Cerium-doped Lanthanum Bromide of equivalent size. Compared to standard analog readout, use of a digital readout method allows improved energy resolution to be obtained with large volume SrI 2 (Eu) crystals. Comparative gamma spectra acquired with LaBr 3 (Ce) and NaI(Tl) quantitatively depict the value of the high resolution of SrI 2 (Eu) in discriminating closely spaced gamma lines for radioisotope identification applications.