Geometric optimization of a neutron detector based on a lithium glass–polymer composite

Mayer, M.; Nattress, J.; Trivelpiece, Cory L.; Jovanovic, Igor

doi:10.1016/j.nima.2014.09.023

Cited by 27 publications

(9 citation statements)

References 12 publications

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“…All simulations were performed using Geant4.10.1 [31]. The size and shape of the detector have been chosen based on the general guidance from prior analyses [13,32]. The volume of the scintillating PVT can be chosen for a given neutron spectrum to achieve efficient thermalization, In all simulations the neutrons are produced by a point source and are incident upon the sidewall and filling the entire aperture of the detector.…”

Section: Detector Simulationmentioning

confidence: 99%

“…The other approach to realize neutron capture-based detectors with neutron/gamma discriminating properties is by combining scintillators of varying scintillation characteristics and neutron sensitivity into heterogeneous structures. Composites of lithium-doped glass embedded within a scintillating polymer [13,14,15,16] and lithium gadolinium borate (LGB) composites [17,18,19], have been demonstrated to be scalable to high efficiency while maintaining moderate cost, and have been used to perform capture-gated spectroscopy [18,19,20,21]. Composite designs that use 6 LiF:ZnS(Ag) scintillators have recently accomplished high levels of gamma discrimination [22].…”

Section: Introductionmentioning

confidence: 99%

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Development and operation of a 6LiF:ZnS(Ag)—scintillating plastic capture-gated detector

Wilhelm

Nattress

Jovanovic

2017

Nuclear Instruments and Methods in Physics Research Section A:

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We report on the design, construction, and operation of a capture-gated neutron detector based on a heterogeneous scintillating structure comprising two scintillator types. A flat, 500 μm thick sheet composed of a mixture of lithium-6-fluoride capture agent, 6 LiF, and zinc sulfide phosphor, ZnS(Ag), is wrapped around scintillating polyvinyl toluene (PVT) in a form of cylinder. The 6 LiF:ZnS(Ag) sheet uses an aluminum foil backing as a support for the scintillating material and as an optical reflector, and its optical properties have been characterized independently. The composite scintillator was tested using 252 Cf, DD fusion, 137 Cs, and 60 Co sources. The intrinsic detection efficiency for neutrons from an unmoderated 252 Cf source and rejection of gammas from 137 Cs were measured to be 3.6% and 10 −6 , respectively. A figure of merit for pulse shape discrimination of 4.6 was achieved, and capture-gated spectroscopic analysis is demonstrated.

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Section: Detector Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development and operation of a 6LiF:ZnS(Ag)—scintillating plastic capture-gated detector

Wilhelm

Nattress

Jovanovic

2017

Nuclear Instruments and Methods in Physics Research Section A:

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“…By constricting geometrical dimensions and careful material selection, discrimination Spectroscopic neutron detection using composite scintillators 1660232-3 between neutrons and gammas can be achieved through both pulse height and shape analysis. 2,3 Fig. 1.…”

Section: Principle Of Operation Of a Composite Scintillation Detectormentioning

confidence: 99%

“…The design and simulation of our detector architecture using the Geant4 framework has been previously described in detail. 2 Here we provide additional results relevant for detector scaling and neutron spectroscopy. The predicted capture efficiency for prompt neutrons produced by the 252 Cf source for a 50 mm diameter detector with a 6% weight…”

Section: Detector Simulationmentioning

confidence: 99%

Spectroscopic neutron detection using composite scintillators

Jovanovic

Foster

Kukharev

et al. 2016

Int. J. Mod. Phys. Conf. Ser.

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Shielded special nuclear material (SNM), especially highly enriched uranium, is exceptionally difficult to detect without the use of active interrogation (AI). We are investigating the potential use of low-dose active interrogation to realize simultaneous high-contrast imaging and photofission of SNM using energetic gamma-rays produced by low-energy nuclear reactions, such as 11 B(d,nγ) 12 C and 12 C(p,p′) 12 C. Neutrons produced via fission are one reliable signature of the presence of SNM and are usually identified by their unique timing characteristics, such as the delayed neutron die-away. Fast neutron spectroscopy may provide additional useful discriminating characteristics for SNM detection. Spectroscopic measurements can be conducted by recoil-based or thermalization and capture-gated detectors; the latter may offer unique advantages since they facilitate low-statistics and event-by-event neutron energy measurements without spectrum unfolding. We describe the results of the development and characterization of a new type of capture-gated spectroscopic neutron detector based on a composite of scintillating polyvinyltoluene and lithium-doped scintillating glass in the form of millimeter-thick rods. The detector achieves >10 8 neutron-gamma discrimination resulting from its geometric properties and material selection. The design facilitates simultaneous pulse shape and pulse height discrimination, despite the fact that no materials intrinsically capable of pulse shape discrimination have been used to construct the detector. Accurate single-event measurements of neutron energy may be possible even when the energy is relatively low, such as with delayed fission neutrons. Simulation and preliminary measurements using the new composite detector are described, including those conducted using radioisotope sources and the low-dose active interrogation system based on low-energy nuclear reactions.

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“…A detailed description of the detector geometry optimization, prototype fabrication, and performance characterization can be found in Refs. [7,10]. The composite detector exhibits pulse shape discrimination (PSD) properties due to the different scintillation decay times of the two distinct materials used in the composite.…”

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confidence: 99%

Neutron spectroscopy by thermalization light yield measurement in a composite heterogeneous scintillator

Shi

Nattress

Mayer

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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An exothermic neutron capture reaction can be used to uniquely identify neutrons in particle detectors. With the use of a capture-gated coincidence technique, the sequence of scatter events that lead to neutron thermalization prior to the neutron capture can also be used to measure neutron energy. We report on the measurement of thermalization light yield via a time-of-flight technique in a polyvinyl toluene-based scintillator EJ-290 within a heterogeneous composite detector that also includes 6 Li-doped glass scintillator. The thermalization light output exhibits a strong correlation with neutron energy because of the preference for near-complete energy deposition prior to the 6 Li(n,t) 4 He neutron capture reaction. The nonproportionality of the light yield from nuclear recoils contributes to the observed broadening of the distribution of thermalization light output. The nonproportional dependence of the scintillation light output in the EJ-290 scintillator as a function of proton recoil energy has been characterized in the range of 0.3-14.1 MeV via the Birks parametrization through a combination of time-of-flight measurement and previously conducted measurements with monoenergetic neutron sources.

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Geometric optimization of a neutron detector based on a lithium glass–polymer composite

Cited by 27 publications

References 12 publications

Development and operation of a 6LiF:ZnS(Ag)—scintillating plastic capture-gated detector

Development and operation of a 6LiF:ZnS(Ag)—scintillating plastic capture-gated detector

Spectroscopic neutron detection using composite scintillators

Neutron spectroscopy by thermalization light yield measurement in a composite heterogeneous scintillator

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