Comparative Gamma Spectroscopy with SrI2(Eu), GYGAG(Ce) and Bi-loaded Plastic Scintillators

Conference · Fri Nov 19 00:00:00 EST 2010

OSTI ID:1016302

Cherepy, N J

We are developing new scintillator materials that offer potential for high resolution gamma ray spectroscopy at low cost. Single crystal SrI{sub 2}(Eu) offers {approx}3% resolution at 662 keV, in sizes of {approx}1 in{sup 3}. We have developed ceramics processing technology allowing us to achieve cubic inch scale transparent ceramic scintillators offering gamma spectroscopy performance superior to NaI(Tl). We fabricated a bismuth-loaded plastic scintillator that demonstrates energy resolution of {approx}8% at 662 keV in small sizes. Gamma ray spectroscopy can be used to identify the presence of weak radioactive sources within natural background. The ability to discriminate close-lying spectral lines is strongly dependent upon the energy resolution of the detector. In addition to excellent energy resolution, large volume detectors are needed to acquire sufficient events, for example, to identify a radioactive anomaly moving past a detector. We have employed a 'directed search' methodology for identifying potential scintillator materials candidates, resulting in the discovery of Europium-doped Strontium Iodide, SrI{sub 2}(Eu), Cerium-doped Gadolinium Garnet, GYGAG(Ce), and Bismuth-loaded Polymers. These scintillators possess very low self-radioactivity, offer energy resolution of 3-8% at 662 keV, and have potential to be grown cost-effectively to sizes similar to the most widely deployed gamma spectroscopy scintillator, Thallium-doped Sodium Iodide, NaI(Tl). In this study, gamma ray spectra of a variety of sources, were obtained employing SrI{sub 2}(Eu), GYGAG(Ce), Bi-loaded polymers, LaBr{sub 3}(Ce), and NaI(Tl). The effects of detector size, energy resolution, and background radioactivity (including self-radioactivity) on the ability to distinguish weak sources is quantified, based on a simple model, and qualitatively compared to laboratory data.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 1016302
• Report Number(s): LLNL-PROC-462914; TRN: US1103037
• Resource Relation: Conference: Presented at: IEEE Nuclear Science Symposium, Knoxville, TN, United States, Oct 30 - Nov 06, 2010
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUMM MECHANICS
GENERAL PHYSICS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
36 MATERIALS SCIENCE
CERAMICS
ENERGY RESOLUTION
GADOLINIUM
GAMMA SPECTROSCOPY
MONOCRYSTALS
PERFORMANCE
PHOSPHORS
PLASTIC SCINTILLATORS
POLYMERS
PROCESSING
RADIOACTIVITY
RESOLUTION
SODIUM IODIDES
SPECTRA
SPECTROSCOPY
STRONTIUM IODIDES