A phoswich design using real-time rise time discrimination for Compton suppression of LaBr[formula omitted]:Ce detector

Abstract

As one of the detectors with superior performances, the Compton continuum in the spectra of the Cerium-doped Lanthanum 3-Bromide (LaBr3:Ce) detector should be suppressed for better performances. A compacted LaBr3:Ce/NaI:Tl phoswich detector has been designed to reduce the Compton continuum and improve the peak-to-total (P/T) ratio of the photopeaks. The LaBr3:Ce scintillator is surrounded by a well-type NaI:Tl scintillator and is coupled to a single photomultiplier tube (PMT). The Compton continuum is reduced by identifying the gamma-ray energy depositions in different scintillators using the real-time rise time discrimination (RTD) method. A Geant4 code with actual geometry was performed to simulate the suppressed and unsuppressed spectra. The peak efficiency of total energy at 1332 keV and 662 keV is 1.58% and 2.75%, the peak to total ratio at 137Cs point source and 60Co point source are 0.545 and 0.367, respectively. The reduction of the Compton continuum and the improvement of the P/T ratio will greatly expand the application range of the LaBr3: Ce detector in low-intensity measurements.