Compton Edge Convolutional Model and Algorithm for Energy-channel Calibration

TL;DR

This work tackles the challenge of calibrating scintillation detectors when full-energy peaks are weak or absent by introducing a convolution-based method to fit the Compton edge. The approach models the measured spectrum as a convolution of the true spectrum with a Gaussian-like resolution function, linking the Compton-edge energy $E_{e,\max}$ to the observed channel by extracting parameters $B$, $A$, and $σ$ from the fit. Using BC408, NaI, and LaBr$_3$ detectors and ${}^{137}$Cs sources, the authors validate that the Compton-edge calibration agrees with full-energy-peak calibrations to within $1\%$, demonstrating broad applicability across detector materials. The method relies on the Klein–Nishina differential cross section and the resulting recoil-electron energy distribution, enabling automated, universal calibration without reliance on prominent full-energy peaks. This could significantly improve radiation-detection precision in dosimetry, environmental monitoring, and medical imaging by providing a robust alternative calibration pathway for Compton-dominated spectra.

Abstract

Scintillation detectors are essential tools for radiation measurement, but calibrating them accurately can be challenging, especially when full-energy peaks are not prominent. This is common in detectors like plastic scintillators. Current methods for calibrating these detectors often require manual adjustments. To address this, we propose a new method called the convolution model. This model accurately calibrates the energy-channel relationship of the Compton edge in various detectors. We tested it with plastic scintillator BC408, NaI crystal, and LaBr$_3$ crystal. Using ${}^{137}$Cs radioactive sources, we calibrated NaI and LaBr$_3$ detectors using full-energy peaks, then applied the convolution model to fit the Compton edge. Our results show errors within 1\% when compared to full-energy peak calibration.

Figures (8)

• Figure 1: Schematic diagram of the Compton effect
• Figure 2: Differential Cross Section for Recoil Electron Energy
• Figure 3: convolution process
• Figure 4: Differential Cross Section for Recoil Electron Energy
• Figure 5: Compton Edge Fitting