Fast pulse sampling module for real-time neutron–gamma discrimination

• Published in: Nuclear science and techniques Vol. 30; no. 5; pp. 130 - 137
• Main Authors: Cai, Jia-Le, Li, Dao-Wu, Wang, Pei-Lin, Zhang, Zhi-Ming, Li, Xiao-Hui, Feng, Bao-Tong, Hu, Ting-Ting, Tong, Teng, Zhou, Wei, Wei, Long
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.05.2019; School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China%Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China; Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
• Subjects: Energy; Hadrons; Heavy Ions; Nuclear Energy; Nuclear Physics; Neutron–gamma discrimination; Real time; Domino Ring Sampler 4; Plastic scintillators; Neutron-gamma discrimination
• ISSN: 1001-8042; 2210-3147
• DOI: 10.1007/s41365-019-0595-1

An adaptable and compact fast pulse sampling module was developed for the neutron–gamma discrimination. The developed module is well suited for low-cost and low-power consumption applications. It is based on the Domino Ring Sampler 4 (DRS4) chip, which offers fast sampling speeds up to 5.12 giga samples per second (GSPS) to digitize pulses from front-end detectors. The high-resolution GSPS data is useful for obtaining precise real-time neutron–gamma discrimination results directly in this module. In this study, we have implemented real-time data analysis in a field programmable gate array. Real-time data analysis involves two aspects: digital waveform integral and digital pulse shape discrimination (PSD). It can significantly reduce the system dead time and data rate processed offline. Plastic scintillators (EJ-299-33), which have proven capable of PSD, were adopted as neutron detectors in the experiments. A photomultiplier tube (PMT) (model #XP2020) was coupled to one end of a detector to collect the output light from it. The pulse output from the anode of the PMT was directly passed onto the fast sampling module. The fast pulse sampling module was operated at 1 GSPS and 2 GSPS in these experiments, and the AmBe-241 source was used to examine the neutron–gamma discrimination quality. The PSD results with different sampling rates and energy thresholds were evaluated. The figure of merit (FOM) was used to describe the neutron–gamma discrimination quality. The best FOM value of 0.91 was obtained at 2 GSPS and 1 GSPS sampling rates with an energy threshold of 1.5 MeV ee (electron equivalent).