Active fast neutron singles assay of 235U enrichment in small samples of triuranium octoxide

Parker, Helen M. O'd.; Aspinall, Michael; Couture, A.; Cave, Frank; Orr, C.H.; Swinson, Bryan; Joyce, Malcolm J.

doi:10.1016/j.pnucene.2016.07.022

Cited by 7 publications

(5 citation statements)

References 11 publications

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“…As an alternative, active neutron methods such as active neutron multiplicity counting (Ensslin et al 2007) use an external source of neutrons (typically an 241 Am-Li source) in an active well coincidence counter to induce fissions of 235 U. Coincident detection of the emitted neutrons by several neutron detectors allows the 235 U mass to be determined. The overall accuracy of 235 U enrichment was estimated to only be 4.4% relative (±0.9 wt% at 20% enrichment) (Dolan et al 2014, Parker et al 2016.…”

Section: Neutron-based Techniquesmentioning

confidence: 93%

Evaluation of Uranium-235 Measurement Techniques

Kaspar

Lavender

Dibert

2017

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Section: Neutron-based Techniquesmentioning

confidence: 93%

Evaluation of Uranium-235 Measurement Techniques

Kaspar

Lavender

Dibert

2017

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“…The controller includes an FPGA-based data acquisition card and custom-built analysis software developed in LabVIEW [7], [14]. 2) custommade de-randomizing electronics (Los Alamos National Laboratory, NM) connected to a JSR-15 multiplicity shift register (Canberra Industries Inc., CT) for the measurement of Uranium-235 enrichment in small samples of low-enriched triuranium octoxide [15], and 3) a bespoke 32-bit, 64-channel, binary counter with a serial PC interface (Lancaster University, UK) for reactor imaging [13] and neutron tomography using an isotropic source [16]. In addition, the commercially available multichannel Pulse Train Recorder (model: PTR-32) by the Institute of Isotopes (Hungarian Academy of Sciences or Energia, Budapest) is also fully compatible with the MFAx technology and offers an embedded de-randomizing function.…”

Section: A Review Of the Measurementsmentioning

confidence: 99%

Real-Time Capabilities of a Digital Analyzer for Mixed-Field Assay Using Scintillation Detectors

Aspinall

Joyce

Lavietes

et al. 2017

IEEE Trans. Nucl. Sci.

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Abstract-Scintillation detectors offer a single-step detection method for fast neutrons and necessitate real-time acquisition, whereas this is redundant in two-stage thermal detection systems using helium-3 and lithium-6, where the fast neutrons need to be thermalized prior to detection. The relative affordability of scintillation detectors and the associated fast digital acquisition systems have enabled entirely new measurement setups that can consist of sizeable detector arrays. These detectors in most cases rely on photo-multiplier tubes which have significant tolerances and result in variations in detector response functions. The detector tolerances and other environmental instabilities must be accounted for in measurements that depend on matched detector performance. This paper presents recent advances made to a high-speed FPGA-based digitizer. The technology described offers a complete solution for fast-neutron scintillation detectors by integrating multichannel high-speed data acquisition technology with dedicated detector high-voltage supplies. This configuration has significant advantages for large detector arrays that require uniform detector responses. We report on bespoke control software and firmware techniques that exploit realtime functionality to reduce setup and acquisition time, increase repeatability and reduce statistical uncertainties.

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“…ANY application systems adopt multiple organic scintillation detectors for fast neutron assay [1][2][3][4][5][6][7][8][9][10][11]. Detector arrays of this sort can consist of tens of detectors that rely on photo-multiplier tube (PMT) technology for scintillation light capture, voltage conversion and signal amplification.…”

Section: Introductionmentioning

confidence: 99%

Modeling Photo-multiplier Gain and Regenerating Pulse Height Data for Application Development

Aspinall¹,

Jones²

2018

EPJ Web Conf.

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Abstract-Systems that adopt organic scintillation detector arrays often require a calibration process prior to the intended measurement campaign to correct for significant performance variances between detectors within the array. These differences exist because of low tolerances associated with photo-multiplier tube technology and environmental influences. Differences in detector response can be corrected for by adjusting the supplied photo-multiplier tube voltage to control its gain and the effect that this has on the pulse height spectra from a gamma-only calibration source with a defined photo-peak. Automated methods that analyze these spectra and adjust the photomultiplier tube bias accordingly are emerging for hardware that integrate acquisition electronics and high voltage control. However, development of such algorithms require access to the hardware, multiple detectors and calibration source for prolonged periods, all with associated constraints and risks. In this work, we report on a software function and related models developed to rescale and regenerate pulse height data acquired from a single scintillation detector. Such a function could be used to generate significant and varied pulse height data that can be used to integration-test algorithms that are capable of automatically response matching multiple detectors using pulse height spectra analysis. Furthermore, a function of this sort removes the dependence on multiple detectors, digital analyzers and calibration source. Results show a good match between the real and regenerated pulse height data. The function has also been used successfully to develop auto-calibration algorithms.

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Active fast neutron singles assay of 235U enrichment in small samples of triuranium octoxide

Cited by 7 publications

References 11 publications

Evaluation of Uranium-235 Measurement Techniques

Evaluation of Uranium-235 Measurement Techniques

Real-Time Capabilities of a Digital Analyzer for Mixed-Field Assay Using Scintillation Detectors

Modeling Photo-multiplier Gain and Regenerating Pulse Height Data for Application Development

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