Identification of different reaction channels of high energy neutrons in liquid scintillators by the pulse shape discrimination method (original) (raw)
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Pulse shape analysis of liquid scintillators for neutron studies
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2002
The acquisition of signals from liquid scintillators with Flash ADC of high sampling rate ð1 GS=sÞ has been investigated. The possibility to record the signal waveform is of great advantage in studies with g's and neutrons in a high count-rate environment, as it allows to easily identify and separate pile-up events. The shapes of pulses produced by g-rays and neutrons have been studied for two different liquid scintillators, NE213 and C 6 D 6 : A 1-parameter fitting procedure is proposed, which allows to extract information on the particle type and energy. The performance of this method in terms of energy resolution and n=g discrimination is analyzed, together with the capability to identify and resolve pile-up events. r (N. Colonna).
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015
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, the 4 He-based detector registered a maximum scintillation-light 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, and above 750 keV ee its signal was unambiguously neutron.
The response of a liquid scintillator detector to 21– neutrons
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2002
A large volume ð4 lÞ liquid NE213 scintillator detector for neutrons in the energy range up to 800 MeV has been calibrated using a high accuracy tagging technique at E n ¼ 21; 34; 50; 60 and 100 MeV. The experiment is described together with a discussion of the accuracy in the absolute efficiency calibration. Results are presented on total and differential detection efficiencies along with information on the underlying nuclear reactions causing the detector response, including both charged particles and g-rays. The present results complement previous measurements for the same detector, so that an efficiency calibration now exists over an energy range of E n ¼ 2-800 MeV. The empirical results are compared with a calculated energy dependence of the detector response to neutrons. r (J. Blomgren).
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2004
We have investigated the use of digital pulse processing techniques for n/g pulse shape discrimination (PSD) in liquid scintillators, and the application of these techniques to a capture-gated fast neutron monitor developed using the enriched 10 B-loaded liquid scintillator BC523A. The motivation for this study has been to develop computationally fast digital PSD algorithms that can be implemented in a compact portable fast neutron monitor. The PSD separation achieved with a digital pulse risetime algorithm has a Figure of Merit comparable with previously reported analogue techniques, and provides extremely sensitive fast neutron detection in the presence of a strong gamma background. The capture-gated performance of a 685 cm 3 BC523A liquid scintillator cell was investigated using fast neutrons from an Am-Be source, and the application of digital pulse processing techniques to the capture-gated detection mode is discussed. The measured mean neutron capture time in BC523A was 470780 ns which is a factor of five shorter than that reported for liquid scintillators loaded with natural boron. r
Study of n-γ discrimination with NE213 and BC501A liquid scintillators of different size
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1994
A comparative study of n-y discrimination by the digital charge comparison method was carried out for NE213 and BC501A scintillators of different size coupled to a 130 mm diameter XP4512B photomultiplier. Particularly, the scintillators of diameter 50 mm X50 mm size are compared with those of 4 1 volume (160 mm in diameter and 200 mm in depth). The figure of merit, M, of 3.81 measured with the diameter 50 mm X 50 mm BC501A scintillator at 1 MeV energy lost by recoil electrons, is much better than M of 2.05 as observed with the 4 I volume cell. This is the effect of the reduced photoelectron yield by about 50% determined for the 4 1 volume scintillator. Moreover, the slowing down of the light pulse and multiscattering of neutrons have a further influence on the lowering of the M factor. The study of the M factor versus the initial delay and width of the gate set at the slow component showed that the early light of the slow component represented often by the intermediate component with the decay time constant of about 30 ns is of great importance for the n-y discrimination. Particularly, for the 4 1 volume cells it is sufficient to limit the width of the gate at the slow component to about 300 ns. The comparison of the NE213 and BC501A scintillators showed that the BC501A scintillator exhibits a larger light yield evidently observed for the 4 1 volume cell and thus giving a better n-y discrimination.
Response to Neutrons and γ-rays of Two Liquid Scintillators
Journal of Nuclear Physics, Material Sciences, Radiation and Applications
UltimaGold TM AB and OptiphaseTrisafe are two liquid scintillators made by Perkin Elmer and EG & G Company respectively. Both are commercially promoted as scintillation detectors for α and β particles. In this work, the responses to γ-rays and neutrons of UltimaGold TM AB and OptiphaseTriSafe liquid scintillators, without and with reflector, have been measured aiming to use these scintillators as γ-rays and neutron detectors. Responses to γ-rays and neutrons were measured as pulse shape spectra in a multichannel analyzer. Scintillators were exposed to gamma rays produced by 137 Cs, 54 Mn, 22 Na and 60 Co sources. The response to neutrons was obtained with a 241 AmBe neutron source that was measured to 25 and 50 cm from the scintillators. The pulse height spectra due to gamma rays are shifted to larger channels as the photon energy increases and these responses are different from the response due to neutrons. Thus, UltimaGold TM AB and OptiphaseTrisafe can be used to detect γ-rays and neutrons.
Pulse-shape discrimination in NE213 liquid scintillator detectors
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2013
The 16-channel fast stretcher BaFPro module, originally developed for processing signals of Barium Fluoride scintillators, has been modified to make a high performing analog pulse-shape analysis of signals from the NE213 liquid scintillators of the EDEN neutron detector array. The module produces two Gaussian signals, whose amplitudes are proportional to the height of the fast component of the output light and to the total energy deposited into the scintillator, respectively. An in-beam test has been performed at INFN-LNS (Italy) demonstrating a low detection threshold, a good pulse-shape discrimination even at low energies and a wide dynamic range for the measurement of the neutrons energy.
Measured response of a liquid scintillation detector to quasi- monoenergetic electrons and neutrons
Journal of Instrumentation, 2018
The response of a liquid scintillator (EJ-301) to monoenergetic electrons tagged by Compton backscattered gamma-rays has been measured using various radioactive -ray sources. It is observed that the measured electron response is linear up to an energy of 4 MeV. The resolution of the liquid scintillator at an energy 1 MeVee is found to be 11%. The pulse shape discrimination and pulse height response of the liquid scintillator for neutrons have been measured using the 7Li(p,n1)7Be*(0.429 MeV) reaction. A nonlinear response to mono-energetic neutrons for the liquid scintillator is observed at energies En=5.3 MeV, 9.0 MeV and 12.7 MeV. In addition, the measured response of the liquid scintillator for electrons and neutrons has been compared with simulated results obtained using the Monte Carlo based Geant4 toolkit.
New shapes for liquid scintillation detectors used in neutron spectrometry
New shapes for liquid scintillation detectors were developed as a neutron spectrometer in mixed fields n/g. Both simulations with MCNPX and an experimental set-up have been performed in order to test and optimize the geometric parameters of a new BC501-Abased scintillation detector. In order to enhance the pulse shape discrimination, the study of the influence of removing dissolved oxygen has been carried out by optimizing the bubbling time. The new shapes were compared with commercial detectors and show an improved performance for the g=n discrimination. r
Manufacture of a fast neutron detector using EJ-301 liquid scintillator
Science and Technology Development Journal - Natural Sciences
A fast neutron detector using the EJ- 301 scintillator was manufactured for study on detecting fast neutrons and gamma-rays. Detector characteristics include the energy linearity, the efficiency response and the neutron/gamma discrimination were guaranteed for neutron detection in the energy range from 50 to 3000 keVee. The ability discrimination of neutrons/gamma-rays of the detector was evaluated by the charge comparison (CC) method using an 252Cf source. The total efficiencies when measured on 22Na, 137Cs, 60Co and 252Cf sources were obtained 17.8%, 3.9%, 9.8% and 14.8%, respectively. The Figure of Merit (FoM) values of CC method were 0.4–1.55 for the range of energy 50–1000 keVee (keV electron equivalent).
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