Gammastic: Towards a pseudo-gamma spectrometry in plastic scintillators

Matthieu Hamel (1) , Chrystèle Dehe-Pittance (1) , Romain Coulon (1) , Frédérick Carrel (1) , Philippe Pillot (1) , Eric Barat (1) , Thomas Dautremer (1) , Thierry Montagu (1) , Stéphane Normand (1)

1 LCAE (CEA, LIST) - Laboratoire Capteurs et Architectures Electroniques (CEA, LIST)

War against CBRN-E threats needs to continuously develop sensors with improved detection efficiency. More particularly, this topic concerns the NR controls for homeland security. A first analysis requires indeed a fast gamma spectrometry so as to detect potential special nuclear materials (SNM). To this aim, plastic scintillators could represent the best alternative for the production of large-scale, low-cost radiation portal monitors to be deployed on boarders, tolls, etc. Although they are known to be highly sensitive to gamma rays, due to their poor resolution, information relative to the nature of the SNM is tricky. Thus, only the Compton edge is obtained after interaction, and no information of the photoelectric peak is observed. This project concerns new developments on a possible pseudo-gamma spectrometry performed with plastic scintillators. This project is articulated on a combination of two developments: The design of new materials most suitable for recovering the photoelectric peak after gamma interaction with the scintillator. This work concerns mainly plastic scintillators loading with heavy elements, such as lead or bismuth. The analysis of the resulting signal with smart algorithms. This work is thus a pluridisciplinary work performed at CEA LIST and embeds 4 main disciplines: MCNPX simulations (simulated spectra), chemistry of materials (preparation of various plastic scintillators with different properties), instrumentation (lab experiments) and smart algorithms. Really impressive results were obtained with the unfolding of simulated spectra at various energies (from 241Am to 60Co) and an innovative approach was proposed to counter-balance the quenching effect of luminescence by heavy elements in plastic scintillators.

Mots clés: Plastics; Lead; Deconvolution; Nuclear measurements; Scintillation counters; Gamma-rays; Spectroscopy; Inference algorithms; Bismuth; gamma-ray spectroscopy; Monte Carlo; national security; nuclear materials safeguards; solid scintillation detectors; pseudogamma spectrometry; CBRN-E threats; chemical threats; biological threats; radiological threats; nuclear threats; high yield explosive threats; sensor detection efficiency; homeland security; fast gamma spectrometry; special nuclear material detection; large scale radiation portal monitors; low cost radiation portal monitors; Compton edge; photoelectric peak; scintillator-gamma interaction; lead loaded plastic scintillators; bismuth loaded plastic scintillators; MCNPX simulations; material chemistry; plastic scintillator preparation; 241Am simulated spectra; 60Co simulated spectra; luminescence; instrumentation; nuclear instrumentation; simulation; plastic scintillator; particle transport

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Analyse de données, Statistiques et Probabilités [physics.data-an]; Instrumentations et Détecteurs [physics.ins-det]

Matthieu Hamel, Chrystèle Dehe-Pittance, Romain Coulon, Frédérick Carrel, Philippe Pillot, et al.. Gammastic: Towards a pseudo-gamma spectrometry in plastic scintillators. 2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications (ANIMMA), Jun 2013, Marseille, France. pp.06727889, ⟨10.1109/ANIMMA.2013.6727889⟩. ⟨cea-01822346⟩