scholarly journals FAST NEUTRON RESPONSE OF A 6Li-LOADED LIQUID SCINTILLATOR

2007 ◽  
Author(s):  
Masateru Hayashi ◽  
Yukinobu Watanabe ◽  
Daisuke Kaku ◽  
Hideki Nakashima ◽  
Kenshi Sagara
Keyword(s):  
Fast Neutron ◽  
Liquid Scintillator

scholarly journals Timing Characterization of Helium-4 Fast Neutron Detector with EJ-309 Organic Liquid Scintillator

2018 ◽  
Vol 170 ◽  
pp. 07005 ◽  
Author(s):  
Yinong Liang ◽  
Ting Zhu ◽  
Andreas Enqvist
Keyword(s):  
Fast Neutron ◽  
Time Resolution ◽  
High Speed ◽  
Liquid Scintillator ◽  
Moving Average ◽  
Organic Liquid ◽  
Scintillation Detectors ◽  
Arrival Times ◽  
Helium 4 ◽  
Constant Fraction Discriminator

Recently, the Helium-4 gas fast neutron scintillation detectors is being used in time-sensitive measurements, such time-of-flight and multiplicity counting. In this paper, a set of time aligned signals was acquired in a coincidence measurement using the Helium-4 gas detectors and EJ-309 liquid scintillators. The high-speed digitizer system is implanted with a trigger moving average window (MAW) unit combing with its constant fraction discriminator (CFD) feature. It can calculate a “time offset” to the timestamp value to get a higher resolution timestamp (up to 50 ps), which is better than the digitizer's time resolution (4 ns) [1]. The digitized waveforms were saved to the computer hard drive and post processed with digital analysis code to determine the difference of their arrival times. The full-width at half-maximum (FWHM) of the Gaussian fit was used as to examine the resolution. For the cascade decay of Cobalt-60 (1.17 and 1.33 MeV), the first version of the Helium-4 detector with two Hamamatsu R580 photomultipliers (PMT) installed at either end of the cylindrical gas chamber (20 cm in length and 4.4 cm in diameter) has a time resolution which is about 3.139 ns FWHM. With improved knowledge of the timing performance, the Helium-4 scintillation detectors are excellent for neutron energy spectrometry applications requiring high temporal and energy resolutions.

Application research on neutron-gamma discrimination based on BC501A liquid scintillator

Kerntechnik ◽  
2021 ◽  
Vol 86 (6) ◽  
pp. 437-444
Author(s):  
J. Luo ◽  
S. Hou
Keyword(s):  
Fast Neutron ◽  
Figure Of Merit ◽  
Gamma Ray ◽  
Liquid Scintillator ◽  
Comparison Method ◽  
Mean Value ◽  
Neutron Multiplicity ◽  
Nuclear Disarmament ◽  
Zero Crossing ◽  
Non Destructive

Abstract Liquid organic scintillators are widely used in non-destructive analysis, which plays an important role in nuclear disarmament verification. This paper focused on studying the neutron-gamma discrimination technology in the fast neutron multiplicity measuring counter based on BC501A liquid scintillation detector. First, the charge comparison method, the zero-crossing time method and the rise time method were compared via the Geant4 and Matlab algorithm, and the result shows that charge comparison has the highest Figure of Merit. Then, a neutron-gamma discrimination system based on the six-probe fast neutron multiplicity counter was built and tested with a conclusion that the mean value of Figure of merit is 1.08, which verify the satisfactory neutron-gamma discriminating capability of the system. Finally, for the uranium samples, the mass are detected by fast neutron multiplicity counter, and the enrichment are measured by the characteristic gamma-ray signals using the system. The experimental results are in good agreement with the actual data.

scholarly journals THE USE OF FAST NEUTRON DETECTION FOR MATERIALS ACCOUNTABILITY

2014 ◽  
Vol 27 ◽  
pp. 1460140 ◽  
Author(s):  
L. F. NAKAE ◽  
G. F. CHAPLINE ◽  
A. M. GLENN ◽  
P. L. KERR ◽  
K. S. KIM ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Fast Neutron ◽  
Liquid Scintillator ◽  
Neutron Detection ◽  
Nuclear Material ◽  
Detector Response ◽  
Surprising Result ◽  
Neutron Detectors ◽  
Detection Techniques ◽  
Fast Neutron Detection

For many years at LLNL, we have been developing time-correlated neutron detection techniques and algorithms for applications such as Arms Control, Threat Detection and Nuclear Material Assay. Many of our techniques have been developed specifically for the relatively low efficiency (a few percent) inherent in man-portable systems. Historically, thermal neutron detectors (mainly 3 He ) were used, taking advantage of the high thermal neutron interaction cross-sections, but more recently we have been investigating the use of fast neutron detection with liquid scintillators, inorganic crystals, and in the near future, pulse-shape discriminating plastics that respond over 1000 times faster (nanoseconds versus tens of microseconds) than thermal neutron detectors. Fast neutron detection offers considerable advantages, since the inherent nanosecond production timescales of fission and neutron-induced fission are preserved and measured instead of being lost in the thermalization of thermal neutron detectors. We are now applying fast neutron technology to the safeguards regime in the form of high efficiency counters. Faster detector response times and sensitivity to neutron momentum show promise in measuring, differentiating, and assaying samples that have modest to very high count rates, as well as mixed neutron sources (e.g., Pu oxide or Mixed Cm and Pu ). Here we report on measured results with our existing liquid scintillator array and promote the design of a nuclear material assay system that incorporates fast neutron detection, including the surprising result that fast liquid scintillator becomes competitive and even surpasses the precision of 3 He counters measuring correlated pairs in modest (kg) samples of plutonium.

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