Time-of-flight neutron spectrum unfolding for mixed-oxide nuclear fuel and plutonium metal using a dual-particle imager

Journal Article · Sat Nov 01 00:00:00 EDT 2014 · Nuclear Science Symposium and Medical Imaging Conference record

DOI:https://doi.org/10.1109/NSSMIC.2014.7431257· OSTI ID:1582004

Hamel, Michael C. ^[1]; Polack, J. Kyle ^[1]; Poitrasson-Riviere, Alexis ^[1]; Klemm, Dietrich D. ^[1]; Flaska, Marek ^[1]; Clarke, Shaun D. ^[1]; Pozzi, Sara A. ^[1]; Tomanin, Alice ^[2]; Peerani, Paolo ^[2]

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1. Univ. of Michigan, Ann Arbor, MI (United States)
2. Joint Research Centre, Ispra (Italy)

A dual-particle imager with sensitivity to both neutrons and photons has been developed for the detection of special nuclear material. This system has the capability to provide spectral information on detected sources that is useful for safeguard applications. In nuclear facilities with high photon background rates, neutron detection can aid in identification and verification capabilities. The dual-particle imager creates a reconstructed neutron spectrum by correlating neutron counts in pairs of liquid scintillators. The reconstructed spectrum, a combination of energy deposited and time-of-flight, contains resolution effects that blur the true, emitted source-spectrum. To reduce the impact of resolution effects, the reconstructed spectrum can be unfolded to create an estimated source spectrum. A statistical technique, maximum-likelihood expectation-maximization, has been shown to produce an unfolded result for Cf-252 and Am-Be. This technique requires a system response-matrix that contains reconstructed spectra for single neutron energies. Since measuring mono-energetic neutrons is difficult, the system-response-matrix is simulated. Monte Carlo modeling with MCNPX-PoliMi has been show to produce an accurate system response. This work expands on previous neutron unfolding results by showing results for mixed-oxide fuel and plutonium metal measured with the dual-particle imager. Furthermore these results also demonstrate the ability of the dual-particle imager to discrimination between spontaneous fission neutrons and (α,n) reaction neutrons.

• Research Organization: Univ. of Michigan, Ann Arbor, MI (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Nonproliferation and Verification Research and Development (NA-22)
• Grant/Contract Number: NA0002481; NA0002534; NE0000324
• OSTI ID: 1582004
• Journal Information: Nuclear Science Symposium and Medical Imaging Conference record, Vol. 2014; Conference: 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), Seattle, WA (United States), 8-15 Nov 2014; Related Information: ISBN 978-1-4799-6097-2; ISSN 1091-0026
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS