A comparison of n-γ discrimination by the rise-time and zero-crossing methods

The n-gamma discrimination performance of two experimental arrangements based on the rise-time method and the zero-crossing method was compared for a 50.8 mm-diametered and 50.8 mm-high BC501A liquid scintillator coupled to a 50.8 mm-diametered 9807B photomultiplier in this work. The low energy limitation of the detected neutron with different detector high voltages and the figure of merit of the n-gamma discrimination in four neutron energy regions (1-2 MeV, 0.75-1 MeV, 0.5-0.75 MeV and below 0.5 MeV) were studied by using the Am-Be neutron source. Under a time statistical model of the photoelectron emission process in scintillation counters, the intrinsic capability of the n-gamma discrimination performance under the optimal condition was evaluated. The experimental results of the zero-crossing method demonstrate a better n-gamma. discrimination performance than those of the rise-time method, which is consistent with the calculated results.