A first comparison of the responses of a 4He-based fast-neutron detector and a NE-213 liquid-scintillator reference detector

Abstract

He NE-213 Scintillation Gamma-rays Fast neutrons Pulse-shape discrimination a b s t r a c t A first comparison has been made between the pulse-shape discrimination characteristics of a novel 4 He-based pressurized scintillation detector and a NE-213 liquid-scintillator reference detector using an Am/Be mixed-field neutron and gamma-ray source and a high-resolution scintillation-pulse digitizer. In particular, the capabilities of the two fast neutron detectors to discriminate between neutrons and gamma-rays were investigated. The NE-213 liquid-scintillator reference cell produced a wide range of scintillation-light yields in response to the gamma-ray field of the source. In stark contrast, due to the size and pressure of the 4 He gas volume, the 4 He-based detector registered a maximum scintillationlight yield of 750 keV ee to the same gamma-ray field. Pulse-shape discrimination for particles with scintillation-light yields of more than 750 keV ee was excellent in the case of the 4 He-based detector. Above 750 keV ee its signal was unambiguously neutron, enabling particle identification based entirely upon the amount of scintillation light produced.

Tagging fast neutrons from a 252 Cf fission-fragment source

“…The ∼1.8 ns FWHM of the gamma-flash distribution is consistent with the observed timing jitter on our PMT signals and the slight tail in the distribution is possibly due to time walk in the electronics. Note that 4 He scintillator is highly insensitive to gamma-rays [14,18] and any electrons produced via Compton scattering or pair production will result in only a very small scintillation signal. These events will be entirely suppressed by the relatively high software Also shown are three representations of the neutron-kinetic energy distribution constructed using the information presented by Thomas in Ref.…”

“…NE-213 is an organic liquid scintillator that has been employed for decades as a fast-neutron detector. The NE-213 liquid-scintillator detector used here has been reported upon earlier [1,18,19]. It consisted of a 62 mm long × 94 mm cylindrical aluminum "cup" fitted with a borosilicate glass optical window [20].…”

Nuclear recoil scintillation linearity of a high pressure 4He gas detector

“…More importantly, the detector is naturally less sensitive to gamma-rays because the recoiling electron will likely travel far enough to deposit some of its energy into the detector wall instead of the scintillating gas [1]. Thus, the main discrimination strategy in the modern iteration of the detector is simply to compare the size of the pulse and discard events below a threshold as electron recoil backgrounds [9,10]. For neutron recoils, on the other hand, the detector has been used to extract spectral information about neutron sources [5,11,12].…”

Multi-Grid detector for neutron spectroscopy: results obtained on time-of-flight spectrometer CNCS

“…Sensitivity to fast neutrons described above also contributes to background. Due to the pulsed nature of a spallation source, fast neutrons due 1The same mechanism, energy loss by inelastic scattering, is used in 4 He detectors for fast neutrons [30]. to the spallation process, arrive in a peak at a fixed time with respect to the elastic peak and other features.…”