⁶LiF:ZnS(Ag) Neutron Detector Performance Optimized Using Waveform Recordings and ROC Curves

Area of Science:

• Nuclear instrumentation
• Radiation detection and measurement

Background:

• Neutron detectors are crucial for various applications, including nuclear physics and security.
• Optimizing neutron sensitivity while rejecting gamma background is a persistent challenge in detector design.

Purpose of the Study:

• To optimize the neutron sensitivity and gamma rejection of a 6LiF:ZnS(Ag)-scintillator-based neutron detector.
• To determine the optimal integration window durations for pulse-shape discrimination (PSD) using a two-window charge comparison (CC) method.
• To identify the optimal bias voltage for the silicon photomultiplier (SiPM) photosensor.

Main Methods:

• Utilized Gaussian separation and Receiver Operating Characteristic (ROC) curves for optimization.
• Recorded detector waveforms using a monochromatic cold neutron beam and gamma sources (137Cs, 60Co).
• Applied a two-window charge comparison (CC) pulse-shape discrimination (PSD) technique to differentiate neutron capture events.

Main Results:

• Optimized integration window durations for the prompt (0-100 ns) and delayed (100-2300 ns) windows were determined.
• The ROC curve analysis confirmed the experimental performance of the optimized detector.
• The optimal bias voltage for the SiPM was identified, enhancing detector performance.

Conclusions:

• The developed pulse-shape discrimination technique effectively optimizes neutron sensitivity and gamma rejection.
• The study provides a methodology for optimizing scintillator-based neutron detectors.
• The findings contribute to the development of more efficient and reliable neutron detection systems.