Instrument Development and Gamma Spectroscopy With Strontium Iodide

Development of the Europium-doped Strontium Iodide scintillator, SrI2(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) SrI2(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 SrI2(Eu) crystals. Comparative gamma spectra acquired with LaBr3(Ce) and NaI(Tl) quantitatively depict the value of the high resolution of in SrI2(Eu) discriminating closely spaced gamma lines for radioisotope identification applications.