Simulation study on identification of gamma ray-emitting radionuclides based on scintillation light output ratios

• Published in: Radiation physics and chemistry (Oxford, England : 1993) England : 1993), 2025-01, Vol.226, p.112178, Article 112178
• Main Authors: Kim, Seunghyeon, Lee, Sangjun, Park, Jae Hyung, Kim, Jinhong, Jegal, Seokhyeon, Song, Siwon, Lee, Bongsoo
• Format: Article
• Language: English
• Subjects: Equivalent energy; Intensity-weighted average energy; MCNP simulation; Radionuclide identification; Scintillation light output ratio
• ISSN: 0969-806X
• DOI: 10.1016/j.radphyschem.2024.112178

Radiation from gamma-ray emitting radionuclides poses significant health risks due to its high penetrating power. Currently, no technique offers effective shielding against it. Nevertheless, the rapid increase in the production and application of radionuclides warrants efficient and reliable radionuclide-detection systems. Although conventional scintillation detectors that adopt spectral analysis are widely used for their cost-effectiveness and robustness, their performance can be hindered by factors such as radioactive statistical fluctuations and background radiation. Advanced spectral-processing techniques, including machine-learning approaches, offer improvements; however, they are generally computationally intensive and not suitable for rapid onsite applications. In this study, a novel analytical approach for radionuclide identification based on the ratio of scintillation light output from scintillators with different attenuation properties is proposed. The scintillator assembly comprises four cylindrical scintillators: bismuth germanate (BGO), cerium-doped gadolinium gallium garnet (GAGG:Ce), europium-doped calcium fluoride (CaF2:Eu), and polyvinyltoluene-based plastic scintillators. The deposited energy in each scintillator is simulated using the Monte Carlo N-Particle Transport (MCNP) code, and the amount of scintillation light output (SLO) is calculated by a mathematical light yield model of the scintillator. From the calculated light output, the light output ratios for different scintillator combinations are derived and their dependence on the energy of incident gamma rays is evaluated. This approach exploits a parameter called equivalent energy to estimate the gamma-ray energy, which is then used to identify gamma ray-emitting radionuclides by comparing the results with known intensity-weighted average energies. The proposed method is validated with both monoenergetic and polyenergetic gamma rays using standard gamma-ray data. The results demonstrate that SLO ratio-based approach can effectively identify radionuclides without relying on traditional spectral measurement techniques, offering a promising alternative for rapid and efficient gamma-ray detection and analysis. •In MCNP simulation, we identify monoenergetic/polyenergetic gamma-ray radionuclides using scintillators.•Scintillators with various characteristics provide diverse radionuclide features.•Scintillation light output ratios allow identification in specific energy levels.•The propos