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Precise measurement under high counting rates has been a major challenge for γ -ray spectroscopy, where signals generally pile up with each other and their characteristic values are deeply coupled. An off-line pile-up pulse recovery algorithm based on template matching is developed for LaBr 3 scintillation detectors and has been applied to data from China Spallation Neutron Source (CSNS) Back-n white neutron beamline. As an improvement to the traditional Template Matching methods, the predetermined template shape is associated with pulse amplitudes, which is found crucial to achieve the best fitting results. Moreover, a universal strategy of setting the initial values of fitting allows to resolve signals that are separated in time by less than the characteristic rise time. Processing of simulated pulses demonstrates that the lower limit of interval to distinguish successive events is 10 ns, which is a significant improvement to the previous works. The algorithm performs well under a counting rate of 6 × 1 0 7 s−1, and is still effective up to 1 0 8 s−1. Analysis of experimental data indicates that this algorithm recovers over 98% count yield under a counting rates of no more than 4 × 1 0 6 s−1 in this work, providing a more reliable approach to deduce neutron-induced reaction cross sections. [ABSTRACT FROM AUTHOR]

The FIssion Neutron spectrum Detector Array (FINDA) has been designed for measurement of prompt fission neutron spectrum on the Back-n beam line at the China Spallation Neutron Source (CSNS). In order to test the neutron- γ discrimination performance of the EJ301 scintillator that will be used as a detector unit in the FINDA, a comparative study using three conventional digital pulse shape discrimination (PSD) methods has been carried out. An Am–Be source has been used to generate the mixed neutron- γ radiation and the waveform data has been obtained with a fast digitizer. Pulse interpolation, baseline restoration and pulses pile-up rejection have been applied for digital pulse processing. Charge comparison (CC) method and simplified charge comparison(SCC) method show a better capability of neutron- γ discrimination than rise time comparison(RTC) method over the entire energy range. Rise time comparison method needs a very fast digitizer or pulse interpolation to improve the PSD ability. The analysis of neutron- γ discrimination performance of the EJ301 scintillator provides a strong technical support for fast neutron measurement using the FINDA at CSNS. • The neutron- γ discrimination performance of an EJ301 scintillator that will used as a detector unit in the FINDA spectrometer at CSNS has been characterized. • A comparative study using three conventional digital pulse shape discrimination (PSD) methods has been carried out. • Charge comparison (CC) method and simplified charge comparison (SCC) method show a better capability of neutron- γ discrimination than rise time comparison (RTC) method over the entire energy range. • With the current test we discussed the results in view of applications on the Back-n beam line at CSNS and the analysis provides a strong technical support for fast neutron measurement using the FINDA. [ABSTRACT FROM AUTHOR]