Optimization and characterization of a coincidence beta-ray spectrometer.

Area of Science:

• Nuclear Physics and Instrumentation
• Radiation Detection and Measurement
• Radiological Physics

Background:

• Accurate beta spectrometry and dosimetry in mixed beta-gamma fields are challenging due to the need to distinguish between radiation types.
• Traditional methods may struggle to effectively reject gamma-ray events, leading to spectral inaccuracies.
• Developing robust systems for radiation discrimination is essential for safety and research applications.

Purpose of the Study:

• To develop and evaluate a novel Si-plastic scintillator coincidence beta-ray spectrometer.
• To achieve pure beta-ray spectra by effectively rejecting gamma-ray detection events.
• To assess the system's performance in mixed beta-gamma fields under varying radiation rates.

Main Methods:

• Utilized a Si-plastic scintillator coincidence setup for beta-ray detection.
• Employed a compact digital processing system to record pulse height and arrival time in list mode.
• Conducted spectral measurements using mixed beta-gamma fields from 90Sr/90Y and 137Cs sources.

Main Results:

• The coincidence spectrometer successfully collected pure beta-ray spectra by rejecting gamma events.
• System performance was evaluated across a range of beta (7.3-241 cps) and gamma (500-8000 cps) count rates.
• The coincidence beta spectrum remained stable and unperturbed by gamma events, except for low-energy perturbations at very low beta-to-gamma count ratios.

Conclusions:

• The developed Si-plastic scintillator coincidence spectrometer is effective for beta spectrometry and dosimetry in mixed fields.
• The coincidence technique provides a reliable method for isolating beta spectra from background gamma radiation.
• Further optimization may be needed for low beta-to-gamma count rate scenarios to mitigate low-energy spectral perturbations.