Assay variance as a figure of merit for neutron multiplicity counters

Ensslin, N.; Dytlewski, N.; Krick, M. S.

doi:10.1016/0168-9002(90)90361-9

Cited by 15 publications

(16 citation statements)

References 7 publications

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“…[16] To illustrate the comparison between fast neutron and thermal neutron-based systems a computer code based on the well-known "Ensslin Figure-of-Merit" algorithms was developed to calculate assay uncertainties for various system parameters. [2] Some example results from this code are illustrated in Figure 1, showing (left) the calculated relative standard deviation (RSD) as a function of sample mass for a representative detection system. Calculations of measurement precision for the individual singles, doubles, and triples rates, as well as the total assay precision, were completed for a range of sample masses.…”

Section: Performance Improvementsmentioning

confidence: 99%

“…Aside from neutron detection efficiency, the die-away time of the detector is perhaps the most critical component of the multiplicity counter. [2] Simply stated, a detection system with a minimal die-away time allows for a correspondingly short counting gate width, and thus, fewer accidental coincidences. RSD's for several sample cases as a function of detector die-away time are shown in Figure 2.…”

Section: Performance Improvementsmentioning

confidence: 99%

“…[1, 2] HLNCC system parameters were either taken directly from the stat sheet on the CANBERRA website or from a similar study performed at Los Alamos National Laboratory. [2] System parameters for the FNMC prototype that could not be determined from simulations were assumed. Table 2 summarizes the parameters used in the calculations for both of the detection systems.…”

Section: Prototype Performance Comparisonmentioning

confidence: 99%

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MPACT Fast Neutron Multiplicity System Prototype Development

Chichester¹,

Pozzi²,

Dolan³

et al. 2013

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This document serves as both an FY2103 End-of-Year and End-of-Project report on efforts that resulted in the design of a prototype fast neutron multiplicity counter leveraged upon the findings of previous project efforts. The prototype design includes 32 liquid scintillator detectors with cubic volumes 7.62 cm in dimension configured into 4 stacked rings of 8 detectors. Detector signal collection for the system is handled with a pair of Struck Innovative Systeme 16-channel digitizers controlled by in-house developed software with built-in multiplicity analysis algorithms. Initial testing and familiarization of the currently obtained prototype components is underway, however full prototype construction is required for further optimization.Monte Carlo models of the prototype system were performed to estimate die-away and efficiency values. Analysis of these models resulted in the development of a software package capable of determining the effects of nearest-neighbor rejection methods for elimination of detector cross talk. A parameter study was performed using previously developed analytical methods for the estimation of assay mass variance for use as a figure-of-merit for system performance. [1, 2] A software package was developed to automate these calculations and ensure accuracy. The results of the parameter study show that the prototype fast neutron multiplicity counter design is very nearly optimized under the restraints of the parameter space.

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Section: Performance Improvementsmentioning

confidence: 99%

Section: Performance Improvementsmentioning

confidence: 99%

Section: Prototype Performance Comparisonmentioning

confidence: 99%

See 1 more Smart Citation

MPACT Fast Neutron Multiplicity System Prototype Development

Chichester¹,

Pozzi²,

Dolan³

et al. 2013

View full text Add to dashboard Cite

show abstract

“…[13] To illustrate the comparison between fast neutron and thermal neutron-based systems a computer code based on the well-known "Ensslin Figure-of-Merit" algorithms was developed to calculate assay uncertainties for various system parameters. [14] Some example results from this code are illustrated in Figure 1, showing (left) the calculated relative standard deviation (RSD) as a function of sample mass for a representative detection system. Calculation of measurement precision for the individual singles, doubles, and triples rates, as well as the total assay precision, were completed for a range of sample masses.…”

Section: Motivation -Performance Improvementmentioning

confidence: 99%

“…[14] Simply stated, a detection system with a minimal die-away time allows for a correspondingly short counting gate width, and, thus, fewer accidental coincidences. RSD's for several sample cases as a function of detector die-away time are shown in Figure 2.…”

Section: Motivation -Performance Improvementmentioning

confidence: 99%

MPACT Fast Neutron Multiplicity System Design Concepts

Chichester¹,

Pozzi²,

Dolan³

et al. 2012

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This report documents work performed by Idaho National Laboratory and the University of Michigan in fiscal year (FY) 2012 to examine design parameters related to the use of fast-neutron multiplicity counting for assaying plutonium for materials protection, accountancy, and control purposes. This project seeks to develop a new type of neutron-measurement-based plutonium assay instrument suited for assaying advanced fuel cycle materials. Some current-concept advanced fuels contain high concentrations of plutonium; some of these concept fuels also contain other fissionable actinides besides plutonium. Because of these attributes the neutron emission rates of these new fuels may be much higher, and more difficult to interpret, than measurements made of plutoniumonly materials. Fast neutron multiplicity analysis is one approach for assaying these advanced nuclear fuels.Studies have been performed to assess the conceptual performance capabilities of a fast-neutron multiplicity counter for assaying plutonium. Comparisons have been made to evaluate the potential improvements and benefits of fast-neutron multiplicity analyses versus traditional thermal-neutron counting systems. Fast-neutron instrumentation, using for example an array of liquid scintillators such as EJ-309, have the potential to either a) significantly reduce assay measurement times versus traditional approaches, for comparable measurement precision values, b) significantly improve assay precision values, for measurement durations comparable to current-generation technology, or c) moderately improve both measurement precision and measurement durations versus current-generation technology. Using the MCNPX-PoliMi Monte Carlo simulation code, studies have been performed to assess the doubles-detection efficiency for a variety of counter layouts of cylindrical liquid scintillator detector cells over one, two, and three rows.Ignoring other considerations, the best detector design is the one with the most detecting volume. However, operational limitations guide a) the maximum acceptable size of each detector cell (due to PSD performance and maximum-acceptable per-channel data throughput rates, limited by pulse pile-up and the processing rate of the electronics components of the system) and b)

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Analysis of neutron multiplicity measurements with allowance for dead-time losses between time-correlated detections

Vincent

1992

Nuclear Instruments and Methods in Physics Research Section A:

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Assay variance as a figure of merit for neutron multiplicity counters

Cited by 15 publications

References 7 publications

MPACT Fast Neutron Multiplicity System Prototype Development

MPACT Fast Neutron Multiplicity System Prototype Development

MPACT Fast Neutron Multiplicity System Design Concepts

Analysis of neutron multiplicity measurements with allowance for dead-time losses between time-correlated detections

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