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Title: Strontium Iodide Instrument Development for Gamma Spectroscopy and Radioisotope Identification

Development of the Europium-doped Strontium Iodide scintillator, SrI2(Eu), has progressed significantly in recent years. SrI2(Eu) has excellent material properties for gamma ray spectroscopy: high light yield (>80,000 ph/MeV), excellent light yield proportionality, and high effective atomic number (Z=49) for high photoelectric cross-section. High quality 1.5 and 2 diameter boules are now available due to rapid advances in SrI2(Eu) crystal growth. In these large SrI2(Eu) crystals, optical self-absorption by Eu2+ degrades the energy resolution as measured by analog electronics, but we mitigate this effect through on-the-fly correction of the scintillation pulses by digital readout electronics. Using this digital correction technique we have demonstrated energy resolution of 2.9% FWHM at 662 keV for a 4 in3 SrI2(Eu) crystal, over 2.6 inches long. Based on this digital readout technology, we have developed a detector prototype with greatly improved radioisotope identification capability compared to Sodium Iodide, NaI(Tl). The higher resolution of SrI2(Eu) yields a factor of 2 to 5 improvement in radioisotope identification (RIID) error rate compared to NaI(Tl).
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  1. Lawrence Livermore National Laboratory (LLNL)
  2. Lawrence Berkeley National Laboratory (LBNL)
  3. Radiation Monitoring Devices, Watertown, MA
  4. Fisk University, Nashville
  5. ORNL
  6. Bridgeport Instruments, Austin, TX
  7. Northrop Grumman SYNOPTICS, North Carolina
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Conference: SPIE Optics + Photonics 2014, San Diego, CA, USA, 20140817, 20140921
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
Work for Others (WFO)
Country of Publication:
United States
scintillators; gamma ray detection; energy resolution; radioisotope identification