Development of a hybrid radiation monitor based on NaI(Li+Tl) and PVT scintillators for homeland security
Résumé
The current geopolitical context and the national requirements of a continuous survey in strategical high frequency civil zones such as airports, seaports and train stations conduct to a growing need to develop performant radiation monitors. In this framework, LIST Institute from CEA Paris-Saclay is currently investigating the development of a novel system based on the coupling of inorganic/organic scintillators, respectively NaILTM from Saint-Gobain Crystals and EJ-200 and plastic scintillators from Eljen technology. Traditional technologies are mainly based on either gamma-ray sensible detectors such as for instance NaI(Tl) like the DIRAD radiological monitor, either on neutron detectors such as classical Radiation Portal Monitors (RPM) based on 3He counters. Recent generation RPM based on plastic scintillators only, proposed for instance by Bertin Technologies or Symetrica Inc., allows both gamma and neutron signatures detection. Nevertheless, their radiological identification capabilities are limited due to the low energy resolution of PVT. To counter this drawback, we hereby propose to deploy NaILTM scintillators, which present similar energy resolution capabilities than traditional NaI(Tl), allowing the identification of distinct radiological threats. Moreover, these detectors discriminate radiological from nuclear threats by means of Pulse Shape Discrimination (PSD) using 6Li component and associated 6Li(n,α)3H reaction. Additional PVT organic scintillators surrounding the NaILTM detectors enable an optimal thermalization of the incident neutron flux in presence of a nuclear threat. In addition, the collected signal of interest (total energy spectra and incident particles detected in coincidence) provides additional information on the threat's nature and increases the systems sensitivity. First proof-of-concept experiments with a 3× 3 NaILTM detector surrounded by cylindrical shaped EJ-200 scintillators and a CAEN® DT5730B digitizer are reported in this paper.
Mots clés
instrumentation
radioactivity
ionizing radiation
nuclear instrumentation
plastic scintillator
inorganic scintillator
organic scintillator
detector
gamma-rays
neutrons
Radiation Portal Monitor
radiological identification
signal processing
spectrum analysis
energy resolution
Pulse Shape Discrimination
Neutron-gamma discrimination
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IEEE_NSS_MIC_2022_NaIL_PVT_radiation_monitors.pdf (3.16 Mo)
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Fichier principal
IEEE_NSS_Summary_2022_NaIL_Vproposal.pdf (542.08 Ko)
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Origine : Fichiers produits par l'(les) auteur(s)