A High-Performance Neutron Time Correlation Counter

Menlove, H.O.; Swansen, J.E.

doi:10.13182/nt85-a33701

Cited by 49 publications

(48 citation statements)

References 3 publications

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“…In our current evaluation, the strongest neutron source available corresponds to an emission rate of 5 Â 10 5 ns À 1 . To estimate the expected neutron count rate based on an emission rate of a high mass plutonium sample, previous measurements using a 3 He-based well counter HLNC-II (High-Level Neutron Coincidence Counter) are considered [8,11]. This counter represents a safeguards standard for the assay of high mass plutonium samples.…”

Section: Selection Of Operating High Voltage and Gamma Sensitivitymentioning

confidence: 99%

Experimental evaluation of a boron-lined parallel plate proportional counter for use in nuclear safeguards coincidence counting

Henzlová¹,

Evans²,

Menlove³

et al. 2013

Nuclear Instruments and Methods in Physics Research Section A:

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Section: Selection Of Operating High Voltage and Gamma Sensitivitymentioning

confidence: 99%

Experimental evaluation of a boron-lined parallel plate proportional counter for use in nuclear safeguards coincidence counting

Henzlová¹,

Evans²,

Menlove³

et al. 2013

Nuclear Instruments and Methods in Physics Research Section A:

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“…This compares favorably with alternative systems such as the Boron plate detector of [18] (FOM¼2.74), and the 3 He-based HLNCC-II detector, a safeguards standard employed by many nuclear facilities and the IAEA [19] (FOM¼2.67). The FOM here is higher primarily because of the efficiency is relatively high, but also because the neutron capture time is short.…”

Section: Discussionmentioning

confidence: 94%

A water-based neutron detector as a well multiplicity counter

Dazeley

Asghari

Bernstein

et al. 2015

Nuclear Instruments and Methods in Physics Research Section A:

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a b s t r a c tWe report the performance characteristics of a water-based neutron detecting multiplicity counter for the non-destructive assay of fissile sources. This technique could replace or supplement existing 3 Hebased multiplicity counters. The counter is a 1.02 m 3 tank containing pure deionized water doped with 0.5% GdCl 3 . It has highly reflective walls and eight 10-in. PMTs mounted at the top. An unshielded source well of 19 cm diameter, mounted at the top and center, extends 73 cm down into the detector. The counter was evaluated using low intensity 252 Cf and 60 Co sources, and a fast pulsing LED to simulate higher intensity backgrounds. At low gamma ray intensities ( $ 200 kBq or less) we report an absolute neutron detection efficiency of 28% and a 60 Co rejection/suppression factor of $ 10 8 to 1. For sources with high gamma ray intensities, the neutron efficiency was 22% 71% up to a 60 Co equivalent activity of 4 MBq. The detector background event rate, primarily due to muons and other cosmogenic particles, was found to be stable over a period of almost three months. The minimum detectable neutron source intensity above background was 3.1 n/s, assuming a one-hour data acquisition.

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“…To demonstrate and test the above theoretical considerations, measurements were performed using both an Epithermal Neutron Multiplicity Counter (ENMC) [12] and a second generation High Level Neutron Coincidence Counter (HLNCC) [13]. The former represents the present state-of-the-art in neutron well counter designs used for safeguards.…”

Section: Experimental Workmentioning

confidence: 99%

The optimum choice of gate width for neutron coincidence counting

Croft¹,

Henzlová²,

Favalli³

et al. 2014

Nuclear Instruments and Methods in Physics Research Section A:

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In the measurement field of international nuclear safeguards, passive neutron coincidence counting is used to quantify the spontaneous fission rate of certain special nuclear materials. The shift register autocorrelation analysis method is the most commonly used approach. However, the Feynman-Y technique, which is more commonly applied in reactor noise analysis, provides an alternative means to extract the correlation information from a pulse train. In this work we consider how to select the optimum gate width for each of these two time-correlation analysis techniques. The optimum is considered to be that which gives the lowest fractional precision on the net doublets rate. Our theoretical approach is approximate but is instructional in terms of revealing the key functional dependence. We show that in both cases the same performance figure of merit applies so that common design criteria apply to the neutron detector head. Our prediction is that near optimal results, suitable for most practical applications, can be obtained from both techniques using a common gate width setting. The estimated precision is also comparable in the two cases. The theoretical expressions are tested experimentally using 252 Cf spontaneous fission sources measured in two thermal well counters representative of the type in common use by international inspectorates. Fast accidental sampling was the favored method of acquiring the Feynman-Y data. Our experimental study confirmed the basic functional dependences predicted although experimental results when available are preferred. With an appropriate gate setting Feynman-Y analysis provides an alternative to shift register analysis for safeguards applications which opening up new avenues of data collection and data reduction to explore.

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A High-Performance Neutron Time Correlation Counter

Cited by 49 publications

References 3 publications

Experimental evaluation of a boron-lined parallel plate proportional counter for use in nuclear safeguards coincidence counting

Experimental evaluation of a boron-lined parallel plate proportional counter for use in nuclear safeguards coincidence counting

A water-based neutron detector as a well multiplicity counter

The optimum choice of gate width for neutron coincidence counting

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