Design of a High-Speed Digital System for Triple Discrimination Based on Stilbene-⁶Li Glass Composite Scintillators...

Area of Science:

• Nuclear instrumentation and detection
• Applied physics
• Radiation detection and measurement

Background:

• Accurate discrimination of neutron types and gamma rays is crucial for various applications, including nuclear security and research.
• Traditional methods face challenges in real-time processing and high-speed signal acquisition.
• Composite scintillators offer enhanced properties for radiation detection.

Purpose of the Study:

• To design and evaluate a high-speed digital prototype system for discriminating fast neutrons, thermal neutrons, and gamma rays.
• To assess the pulse shape discrimination (PSD) performance of a stilbene-6Li glass composite scintillator.
• To develop a cost-effective electronic solution for real-time signal processing in neutron detectors.

Main Methods:

• Utilized a stilbene-6Li glass composite scintillator as the neutron detector.
• Employed a high-speed acquisition board with an AD9434 analog-to-digital converter (ADC) and ZYNQ7020 field-programmable gate array (FPGA).
• Investigated PSD performance at various sampling rates and performed energy calibration using gamma-ray sources.

Main Results:

• Achieved stable PSD performance at sampling rates above 250 MSPS.
• Demonstrated Figure of Merit (FOM) values for neutron/gamma discrimination: 1.26 (fast neutron/γ), 2.18 (fast neutron/thermal neutron), and 3.25 (γ/thermal neutron).
• Measured low false alarm rates (FAR) for common gamma-ray sources (e.g., 0.33% for 60Co).

Conclusions:

• The developed high-speed digital system successfully discriminates between fast neutrons, thermal neutrons, and gamma rays.
• The system integrates waveform discrimination and energy spectrum measurement, meeting design objectives.
• This offers a high-performance, cost-effective electronic solution for advanced neutron detection applications.