Stilbene crystals are used as neutron detectors connected with photomultiplier tubes. An online acquisition method assembled by CAMAC standard plug-ins, NIM plug-ins, a neutron-γ (n-γ) discrimination plug-in named Canberra-2160A, and an offline acquisition method, assembled with an oscilloscope, were developed to obtain nuclear signals from neutron detectors. The online and offline acquisition methods collected pulse signals simultaneously while n-γ discrimination and measurement of deuterium-deuterium (DD) and deuterium-tritium (DT) neutron beam were carried out by both acquisition methods. The resulting n-γ discrimination, detection efficiency, and neutron spectra of varying stilbene crystal sizes were obtained. The neutron events accounted for approximately 80% of the total events in this radiation field formed by DD neutron beam and 50% for DT neutron beam. The results of n-γ discrimination of the two acquisition methods matched very well. The figures of merit (FoM) of n-γ discrimination obtained by the online acquisition method were 2.158 for the radiation field formed by DD neutron beam and 1.802 for DT when over 10 5 pulses were used for analysis. The pulses acquired by the offline acquisition method were repeatedly used to obtain the best discrimination effects, neutron charge-amplitude spectrum, and pulse height spectrum after the particular waveform digitization process. It was shown that the offline acquisition method composed of stilbene crystals, a photomultiplier tube, and a digital oscilloscope could realize the same function and effect as the online acquisition method for monoenergetic neutron beam, but with fewer pulses. A feasible experimental method was obtained which have a good potential for the neutron flux monitoring of the pulsed-neutron radiation fields, in which the total number of events is small or the neutron propagation process is instantaneous.
K: Neutron detectors (cold, thermal, fast neutrons); Scintillators, scintillation and light emission processes (solid, gas and liquid scintillators); Particle identification methods; Digital signal processing (DSP)