Waveform Digitizing for LaBr$_3$/NaI Phoswich Detector

TL;DR

This paper demonstrates that waveform digitizing, combined with careful calibration, can reconstruct full energy events in LaBr3/NaI phoswich detectors, significantly improving detection efficiency by recovering events typically discarded due to Compton scattering.

Contribution

The study introduces a waveform digitizing method with calibration to recover double deposit events, enhancing detector efficiency.

Findings

Efficiency of photopeak at 662 keV increased by a factor of 2.

Full energy reconstruction of double deposit events achieved.

Waveform digitizer effectively recovers events usually rejected in spectral analysis.

Abstract

The detection efficiency of phoswich detector starts to decrease when Compton scattering becomes significant. Events with energy deposit in both scintillators, if not rejected, are not useful for spectral analysis as the full energy of the incident photon cannot be reconstructed with conventional readout. We show that once the system response is carefully calibrated, the full energy of those double deposit events can be reconstructed using a waveform digitizer as the readout. Our experiment suggests that the efficiency of photopeak at 662 keV can be increased by a factor of 2 given our LaBr$_3$/NaI phoswich detector.