Advancements in Gd-based neutron detection: $\gamma - \gamma$ coincidence approach

Jonathan Dumazert (1) , Romain Coulon (1) , Gwenole Corre (1) , Matthieu Hamel (1) , Quentin Lecomte (1) , Vladimir Kondrasovs (1) , Chrystèle Dehé-Pittance (1) , Guillaume Bertrand (1) , Jean-Michel Bourbotte (1) , Sara Garti (1) , Romuald Woo (1)

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

CEA LIST is working on the development of a high-sensitivity thermal neutron counter, based on the insertion of gadolinium in spherical plastic scintillators. As the radiation sensor comprises one or several volumes of scintillating polymers, it is, by nature, sensitive to both neutron and gamma radiations. This property allows the development of a versatile detector, provided that it is possible to algorithmically separate the signature of both types of radiations. The technologically building brick is, moreover, to be implemented in a transportable (<15 kg) system, handled by a first intervention task force in an exposed area. The aim of this paper is to study, both through Monte Carlo simulation and experimentally, an algorithmic architecture of the measurement chain discriminating neutron and gamma events. The presentation is subdivided in three main sections. First, we detail a comparative study between the outputs of a numerical modeling tool, developed to simulate the total response of the sensor to varying radiation sources and the results of a series of experiments carried out in a controlled environment. Second, we describe the building and numerical pre-validation of a simulation code dedicated to the study of consolidated algorithmic architecture, namely γ–γ quasi-coincidence on two adjacent plastic scintillators. Third, we comment on an experimental study of γ–γ quasi-coincidence, Gd-based neutron detection and a comparison between the results and the estimated of the numerical study. We conclude with the presentation of first estimates of neutron sensitivity), gamma-background vulnerability, and n/γ discrimination ratio for the scaled and assessed, material and algorithmic architectures.

Mots clés: nuclear instrumentation; gamma background vulnerability; γ–γ quasi-coincidence; neutron sensitivity; radiation source; n/γ discrimination; sensor; discrimination neutron-gamma; scintillating polymer; neutron; gamma-rays; algorithmic architecture; Modelling; simulation; Monte Carlo; Particle transport; high-sensitivity thermal neutron counter; transportable system; first intervention task force; gadolinium; measurement chain; spherical plastic scintillator; instrumentation; ionizing radiation; plastic scintillator; Radioactivity

Domaines: Instrumentations et Détecteurs [physics.ins-det]; Physique Nucléaire Expérimentale [nucl-ex]; Algorithme et structure de données [cs.DS]; Traitement du signal et de l'image [eess.SP]; Modélisation et simulation; Applications [stat.AP]

Jonathan Dumazert, Romain Coulon, Gwenole Corre, Matthieu Hamel, Quentin Lecomte, et al.. Advancements in Gd-based neutron detection: $\gamma - \gamma$ coincidence approach. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2020, 954, pp.161199. ⟨10.1016/j.nima.2018.09.034⟩. ⟨cea-01916037⟩