Deltoro, J. M. et al, Gadea, A., Perez-Vidal, R. M., Huyuk, T., & Illicachi, R. (2025). Implementation of a double trigger condition system based on charge comparison and TOF measurement for the NEDA detector array. Nucl. Sci. Tech., 36(2), 30–9pp.
Abstract: The NEutron Detector Array (NEDA) is designed to be coupled to gamma-ray spectrometers to enhance the sensitivity of the setup by enabling reaction channel selection through counting of the evaporated neutrons. This article presents the implementation of a double trigger condition system for NEDA, which improves the acquisition of neutrons and reduces the number of gamma rays acquired. Two independent triggers are generated in the double trigger condition system: one based on charge comparison (CC) and the other on time-of-flight (TOF). These triggers can be combined using OR and AND logic, offering four distinct trigger modes. The developed firmware is added to the previous one in the Virtex 6 field programmable gate array (FPGA) present in the system, which also includes signal processing, baseline correction, and various trigger logic blocks. The performance of the trigger system is evaluated using data from the E703 experiment performed at GANIL. The four trigger modes are applied to the same data, and a subsequent offline analysis is performed. It is shown that most of the detected neutrons are preserved with the AND mode, and the total number of gamma rays is significantly reduced. Compared with the CC trigger mode, the OR trigger mode allows increasing the selection of neutrons. In addition, it is demonstrated that if the OR mode is selected, the online CC trigger threshold can be raised without losing neutrons.
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Luo, X. L. et al, Agramunt, J., Egea, F. J., Gadea, A., & Huyuk, T. (2014). Test of digital neutron-gamma discrimination with four different photomultiplier tubes for the NEutron Detector Array (NEDA). Nucl. Instrum. Methods Phys. Res. A, 767, 83–91.
Abstract: A comparative study of the neutron-gamma discrimination performance of a liquid scintillator detector BC501A coupled to four different 5 in photomultiplier tubes (ET9390kb, R11833-100, XP4512 and R4144) was carried out Both the Charge Comparison method and the Integrated Rise-Time method were implemented digitally to discriminate between neutrons and gamma rays emitted by a Cf-252 source. In both methods, the neutron-gamma discrimination capabilities of the four photomultiplier tubes were quantitatively compared by evaluating their figure-of-merit values at different energy regions between 50 keVee and 1000 keVee. Additionally, the results were further verified qualitatively using time-of-flight to distinguish gamma rays and neutrons. The results consistently show that photomultiplier tubes R11833-100 and ET9390kb generally perform best regarding neutron-gamma discrimination with only slight differences in figure-of-merit values. This superiority can be explained by their relatively higher photoelectron yield, which indicates that a scintillator detector coupled to a photomultiplier tube with higher photoelectron yield tends to result in better neutron-gamma discrimination performance. The results of this work will provide reference for the choice of photomultiplier tubes for future neutron detector arrays like NEDA.
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