Phoswich detectors with DSP analysis for low-energy, low-activity photon measurements

Several new phoswich detector designs coupled with digital pulse shape discrimination systems are under development for a variety of radiological measurements. Herein the authors report on two detectors for measuring small activities (nanocurie amounts) of low photon energy (30 to 150 keV) from either isotopic decay or beta-produced bremsstrahlung radiation. The lower limit of detection (LLD), assuming a 60-s counting time, for a phoswich well detector is 0.7 Bq (0.02 nCi) of gamma activity in the 20- to 100-keV range and 11 Bq (0.3 nCi) and 550 (15 nCi) for gamma rays and beta bremsstrahlung X rays, respectively. It is envisioned that these detectors would be useful for biomedical applications or for other measurements requiring low-level, low-energy photon measurement