Measuring and unfolding fast neutron spectra using solution-grown trans-stilbene scintillation detector

• Published in: Nuclear engineering and technology 2023, 55(3), , pp.1021-1030
• Main Authors: Quang, Nguyen Duy, Kim, HongJoo, Vuong, Phan Quoc, Ton, Nguyen Duc, Nam, Uk-Won, Park, Won-Kee, Sohn, JongDae, Choi, Young-Jun, Kim, SungHwan, Youn, SukWon, Ye, Sung-Joon
• Format: Article
• Language: English
• Subjects: Energy calibration; Fast neutron detection; Iterative Bayesian spectrum unfolding; Monte-Carlo simulation; Pulse shape discrimination; Stilbene scintillator; 원자력공학
• ISSN: 1738-5733; 2234-358X
• DOI: 10.1016/j.net.2022.10.041

We propose an overall procedure for measuring and unfolding fast neutron spectra using a trans-stilbene scintillation detector. Detector characterization was described, including the information on energy calibration, detector resolution, and nonproportionality response. The digital charge comparison method was used for the investigation of neutron-gamma Pulse Shape Discrimination (PSD). A pair of values of 600 ns pulse width and 24 ns delay time was found as the optimized conditions for PSD. A fitting technique was introduced to increase the trans-stilbene Proton Response Function (PRF) by 28% based on comparison of the simulated and experimental electron-equivalent distributions by the Cf-252 source. The detector response matrix was constructed by Monte-Carlo simulation and the spectrum unfolding was implemented using the iterative Bayesian method. The unfolding of simulated and measured spectra of Cf-252 and AmBe neutron sources indicates reliable, stable and no-bias results. The unfolding technique was also validated by the measured cosmic-ray induced neutron flux. Our approach is promising for fast neutron detection and spectroscopy.