Minimum Resolution Requirements for Gamma Identification Algorithms

Abstract

Each year, millions are spent to improve detector resolution. This research indicates that higher resolution detectors are not always necessary. The Gamma Detector Response and Analysis Software (GADRAS), Gamma Acquisition and Analysis (Genie), and GammaVision identification routines were employed to analyze simulated NaI spectra of highly enriched uranium (HEU) under various conditions as detector resolution was increased. The purpose was to determine the detector resolution where HEU was no longer identified. The programs were evaluated using six source configurations: bare HEU, with shielding, and with shielding and an interference source. GammaVision was inappropriate for this research because its identification always assigned “peaks” from its library without confidence levels even at 100% resolution. GADRAS identified isotopes using template matching while Genie and GammaVision utilized mathematical routines. GADRAS was the most successful for suboptimal detector resolution isotope identification. Furthermore, suboptimal detector resolutions can effectively identify HEU even with interfering photopeaks.