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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]

A portable Single Sphere Neutron Spectrometer (SSNS) is designed to measure the neutron energy spectrum in the mixed radiation field. The spectrometer consists of a 30 cm diameter single polyethylene moderating sphere with 19 pieces 6Li and 1-piece 7Li glass scintillator detectors located at the orthogonal X/Y/Z axis. The output signals from each detector are processed and readout by the Silicon Photomultipliers (SiPMs) and the Application Specific Integrated Circuit (ASIC) electronic system. The neutron energy responses of portable SSNS are calibrated in the mono-energetic neutron reference fields (144 keV, 1.2 MeV, 5 MeV, 14.8 MeV) based on the 5SDH-2 tandem accelerator in China Institute of Atomic Energy, which are also simulated from 0.0253 eV to 20 MeV by Monte Carlo simulation. The performance of portable SSNS is tested at different distances in 241Am–Be neutron reference radiation field in National Institute of Metrology, China. The fluence response of SSNS is about 0.28 cm2 for 241Am–Be neutron source. • A portable Single Sphere Neutron Spectrometer (SSNS) is designed to measure the neutron energy spectrum. • The output signals from each detector are processed and readout by the SiPMs and the ASIC electronic system. • The SSNS is calibrated in monoenergetic neutron reference radiation fields. • The neutron energy responses are simulated by Monte Carlo simulation. • The performance of portable SSNS is tested in 241Am–Be neutron reference radiation field. [ABSTRACT FROM AUTHOR]