A digital method for pulse-shape discrimination between neutrons and γ rays at a high counting rate and a low energy of detected radiation

Abstract

A digital method for pulse-shape discrimination between neutrons and γ rays was used in measurements at counting rates of up to ∼106 counts/s in the energy range of ∼2–800 keV. Pulses produced by neutrons and γ rays in a stilbene-based scintillation detector were digitized by a digital oscilloscope and transmitted to a computer for carrying out particle identification. Identification was performed for radiation of radionuclide sources and a pulsed neutron generator operating in a repeated triggering mode. Amplitude spectra of pulses identified as neutrons and γ rays of radiation from the generator were measured. At a detector counting rate of ∼8.5 × 105 counts/s, ∼90% of all recorded pulses were recognized as neutrons. In the energy range of ∼30–800 keV, the γ-ray suppression factor was ∼104–103 at counting rates of ∼1.5×105–5 × 105 counts/s, while the efficiency of identifying neutrons was >0.9. The suppression factor for γ rays with an energy of ∼10 keV was ∼300, and the neutron identification efficiency was ∼0.75.