An algorithm for charge-integration, pulse-shape discrimination and estimation of neutron/photon misclassification in organic scintillators

Polack, J. Kyle; Flaska, Marek; Enqvist, Andreas; Sosa, Charles; Lawrence, Christopher; Pozzi, Sara A.

doi:10.1016/j.nima.2015.05.048

Cited by 75 publications

(26 citation statements)

References 13 publications

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“…EJ-309 and NaI(Tl) scintillators were selected to induce scatters in the front plane and to obtain gamma-ray absorptions and neutron scatters in the back plane [5]. Pulse shape discrimination is used in the EJ-309 scintillators to classify events as neutron or gamma-ray events [8].…”

Section: Concept Designmentioning

confidence: 99%

Angular-resolution and material-characterization measurements for a dual-particle imaging system with mixed-oxide fuel

Poitrasson-Rivière

Polack

Hamel

et al. 2015

Nuclear Instruments and Methods in Physics Research Section A:

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a b s t r a c t A dual-particle imaging (DPI) system, capable of simultaneously imaging fast neutrons and gamma rays, has been operated in the presence of mixed-oxide (MOX) fuel to assess the system's angular resolution and material-characterization capabilities. The detection principle is based on the scattering physics of neutrons (elastic scattering) and gamma rays (Compton scattering) in organic and inorganic scintillators. The detection system is designed as a combination of a two-plane Compton camera and a neutronscatter camera. The front plane consists of EJ-309 liquid scintillators and the back plane consists of interleaved EJ-309 and NaI(Tl) scintillators. MCNPX-PoliMi was used to optimize the geometry of the system and the resulting prototype was built and tested using a Cf-252 source as an SNM surrogate. A software package was developed to acquire and process data in real time. The software was used for a measurement campaign to assess the angular resolution of the imaging system with MOX samples. Measurements of two MOX canisters of similar isotopics and intensity were performed for 6 different canister separations (from 51 to 301, corresponding to distances of 21 cm and 131 cm, respectively). The measurements yielded a minimum separation of 201 at 2.5 m (86-cm separation) required to see 2 separate hot spots. Additionally, the results displayed good agreement with MCNPX-PoliMi simulations. These results indicate an angular resolution between 151 and 201, given the 51 step. Coupled with its large field of view, and its capability to differentiate between spontaneous fission and (α,n) sources, the DPI system shows its potential for nuclear-nonproliferation applications.

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Section: Concept Designmentioning

confidence: 99%

Angular-resolution and material-characterization measurements for a dual-particle imaging system with mixed-oxide fuel

Poitrasson-Rivière

Polack

Hamel

et al. 2015

Nuclear Instruments and Methods in Physics Research Section A:

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“…The upper distribution means the pulse had a larger "tail" component than in the lower distribution, so the upper distribution corresponds to neutron pulses and the lower corresponds to photon pulses. For this work we utilized the software tool,SlicePSD [30] to generate the discrimination line in a robust and repeatable way. The SlicePSD generated discrimination line is displayed as the red line on The measured neutron PHD is shown in Fig.4.…”

Section: 0validation Measurement Methodologymentioning

confidence: 99%

Evaluation of neutron light output response functions in EJ-309 organic scintillators

Norsworthy

Poitrasson-Rivière

Ruch

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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An accurate model of the nonlinear detector response of organic scintillators to neutrons is required to correctly simulate fast neutron detection, as well as interpret measured pulse height data. Several empirical and semi-empirical models are available to fit measured scintillator light output data. In this work, EJ-309 light output data from neutrons depositing 1.15 MeV to 5.15 MeV on hydrogen wereanalyzed using empirical models as well as semi-empirical models based on the work of Birks and Voltz. Although all tested models fit the experimental light output data well in the measured range, the models were observed to diverge in low-energy extrapolation. The modelswerethen tested by comparing a measurement and MCNPX-PoliMi simulation of an EJ-309 detector response to fast neutrons from a 252 Cf spontaneous fission source. The agreement between the measured and simulated pulse height distributionsvaried significantly depending on the light output model used. The best agreement between simulated and measured neutron pulse height distributionswas achieved by using the Birks model. The bin-by-bin agreement was better than 5% over the range 0.08 to 2.18 MeVee, and better than 10% from 2.18 to 3.13 MeVee. The integral count rate over the range 0.08 to 3.14 MeVee differed by less than 1% in absolute units. 1.0 Introduction The IAEA is interested in high-fidelity Monte Carlo modeling of detector technologies for international safeguards applications[1]. Several ongoingsafeguards projects employ organic scintillators as fast neutron detectors, such as theLiquid-Scintillator Neutron Coincidence Collar (LS-NCC) [1],the Fast Neutron Multiplicity Counter (UM-FNMC) [2,3],radiation portal monitors (RPMs)[4,5], and the Dual Particle Imager (DPI) [6-8]. Organic scintillators are also frequently employed in a wide variety of applications including, but not limited to, nuclear physics [9], material characterization [6,3,10,2], imaging [6-8], and nuclear medicine[11,12].

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“…Three seconds of RPM data acquisition are triggered when movement is detected by the occupancy sensors. Detector pulses are digitized and pulse shape discrimination based on a charge integration method is used to discern pulses arising from neutron versus gamma ray interactions in the detectors [29]. Pulse shape discrimination, therefore, allows for the creation of Each PHD binon-average containsless than 50 counts after background subtraction.…”

Section: Raw Rpm Datamentioning

confidence: 99%

Radionuclide identification algorithm for organic scintillator-based radiation portal monitor

Paff

Fulvio

Clarke

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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We have developed an algorithm for on-the-fly radionuclide identification for radiation portal monitors using organic scintillation detectors. The algorithm was demonstrated on experimental data acquired with our pedestrian portal monitor on moving special nuclear material and industrial sources at a purpose-built radiation portal monitor testing facility. The experimental data also included common medical isotopes. The algorithm takes the power spectral density of the cumulative distribution function of the measured pulse height distributions and matches these to reference spectra using a spectral angle mapper. F-score analysis showed that the new algorithm exhibited significant performance improvements over previously implemented radionuclide identification algorithms for organic scintillators. Reliable on-the-fly radionuclide identification would help portal monitor operators more effectively screen out the hundreds of thousands of nuisance alarms they encounter annually due to recent nuclear-medicine patients and cargo containing naturally occurring radioactive material. Portal monitor operators could instead focus on the rare but potentially high impact incidents of nuclear and radiological material smuggling detection for which portal monitors are intended.

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An algorithm for charge-integration, pulse-shape discrimination and estimation of neutron/photon misclassification in organic scintillators

Abstract: 2016-11-02T18:49:00

Cited by 75 publications

References 13 publications

Angular-resolution and material-characterization measurements for a dual-particle imaging system with mixed-oxide fuel

Angular-resolution and material-characterization measurements for a dual-particle imaging system with mixed-oxide fuel

Evaluation of neutron light output response functions in EJ-309 organic scintillators

Radionuclide identification algorithm for organic scintillator-based radiation portal monitor

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