Compensated gadolinium-loaded plastic scintillators for thermal neutron detection and counting

Jonathan Dumazert (1) , Romain Coulon (1) , Guillaume H. V. Bertrand (1) , Chrystèle Dehé-Pittance (1) , Matthieu Hamel (1) , Fabien Sguerra (1) , Stéphane Normand (1) , Laurence Méchin (2)

1 LCAE (CEA, LIST) - Laboratoire Capteurs et Architectures Electroniques (CEA, LIST)
2 Equipe Electronique - Laboratoire GREYC - UMR6072

Plastic, scintillator loading with gadolinium-rich organometallic complexes shows a high potential for the deployment of efficient and cost-effective neutron detectors. Due to the low-energy photon and electron signature of thermal neutron capture by gadolinium-155 and gadolinium-157, alternative treatment to Pulse Shape Discrimination has to be proposed in order to display a trustable count rate. This paper discloses the principle of a compensation method applied to a two-scintillator system: a detection scintillator interacts with photon radiation and is loaded with gadolinium organometallic compound to become a thermal neutron absorber, while a non-gadolinium loaded compensation scintillator solely interacts with the photon part of the incident radiation. Posterior to the nonlinear smoothing of the counting signals, a hypothesis test determines whether the resulting count rate after photon response compensation falls into statistical fluctuations or provides a robust image of neutron activity. A laboratory prototype is tested under both photon and neutron irradiations, allowing us to investigate the performance of the overall compensation system in terms of neutron detection, especially with regards to a commercial helium-3 counter. The study reveals satisfactory results in terms of sensitivity and orientates future investigation toward promising axes.

Mots clés: gadolinium-rich organometallic complex; helium-3 counter; photodetector; pulse shaping circuits; solid scintillation detectors; statistical analysis; thermal neutron detection; thermal neutron counting; photon signature; electron signature; thermal neutron capture; gadolinium-155; gadolinium-157; pulse shape discrimination; compensation method; scintillator detection; photon radiation; gadolinium organometallic compound; gadolinium loaded compensation scintillator; counting signal; statistical fluctuation; neutron activity; photon irradiation; neutron irradiation; gadolinium-loaded plastic scintillator; plastic scintillator; detector; nuclear instrumentation; instrumentation; Neutron-gamma discrimination

Domaines: Instrumentations et Détecteurs [physics.ins-det]; Traitement du signal et de l'image [eess.SP]; Physique Nucléaire Expérimentale [nucl-ex]

Jonathan Dumazert, Romain Coulon, Guillaume H. V. Bertrand, Chrystèle Dehé-Pittance, Matthieu Hamel, et al.. Compensated gadolinium-loaded plastic scintillators for thermal neutron detection and counting. 2015 4th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA), Apr 2015, Lisbon, Portugal. pp.7465523, ⟨10.1109/ANIMMA.2015.7465523⟩. ⟨cea-01823371⟩