Single detector-dual scintillator anti-comptom probes

Anti¬-Compton spectrometers have many applications in the fields of safeguards, medicine and security. One of the most important applications is in the location of low energy gamma sources in the presence of high-¬energy gamma background or the location of high-¬energy gamma radiation sources hidden within the same spread of radiation background. In most situations space constraints limit the application of large size detectors or classical anti¬-Compton spectrometers. We have designed a compact anti-¬Compton spectrometer based on a single chip, dual silicon photodetector optically coupled to isolated, annular scintillators. Preliminary room temperature testing with Csl(TI) and LYSO scintillators demon¬strate the readout capabilities of the spectrometer concept. We have measured an outstanding energy resolution of 12 % and 8 % for the 511 keV line from a 22Na source used to excite a LYSO and Csl(TI) respectively. The other variants of Si-Csl(TI) probes is also discussed.