New perspectives for undoped CaF$_2$ scintillator as a threshold activation neutron detector

Pawel Sibczynski (1) , Andrzej Dziedzic (1) , Krystian Grodzicki (1) , Joanna Iwanowska-Hanke (1) , Marek Moszyński (1) , Lukasz Swiderski (1) , Agnieszka Syntfeld-Każuch (1) , Dariusz Wolski (1) , Frédérick Carrel (2) , Amélie Grabowski (2) , Matthieu Hamel (2) , Frederic Laine (2) , Adrien Sari (2) , Alessandro Iovene (3) , Carlo Tintori (3) , Cristiano Fontana (4) , Felix Pino (4)

1 National Centre for Nuclear Research [Otwock]
2 LCAE (CEA, LIST) - Laboratoire Capteurs et Architectures Electroniques (CEA, LIST)
3 CAEN S.p.A.
4 Dipartimento di Fisica e Astronomia "Galileo Galilei"

In this paper we present the prompt photofission neutron detection performance of undoped CaF$_2$ scintillator using Threshold Activation Detection (TAD). The study is carried out in the frame of C-BORD Horizon 2020 project, during which an efficient toolbox for high volume freight non-intrusive inspection (NII) is under development. Technologies for radiation monitoring are the part of the project. Particularly, detection of various radiological threats on country borders plays an important significant role in Homeland Security applications. Detection of illegal transfer of Special Nuclear Material (SNM) - $^{235}$U, $^{233}$U and $^{239}$Pu - is particular due to the potential use for production of nuclear weapon as well as radiological dispersal device (RDD) V known also as a “dirty bomb”. This technique relies on activation of $^{19}$F nuclei in the scintillator medium by fast neutrons and registration of high-energy $\beta$ particles and $\gamma$-rays from the decay of reaction products. The radiation from SNM is detected after irradiation in order to avoid detector blinding. Despite the low $^{19}$F(n,$\alpha$)$^{16}$N or $^{19}$F(n,p)$^{19}$O reaction cross-section, the method could be a good solution for detection of shielded nuclear material. Results obtained with the CaF$_2$ detector were compared with the previous study done for BaF$_2$ and $^3$He detector. These experimental results were obtained using $^{252}$Cf source and 9 MeV Varian Linatron M9 linear accelerator (LINAC). Finally, performance of the prompt neutron detection system based on CaF$_2$ will be validated at Rotterdam Seaport during field trails in 2018.

Mots clés: BaF2; uranium; MCNP; photofission; neutron detection; threshold activation detection; TAD; CaF2; nuclear material; scintillators; fluorine; border monitoring; SNM; instrumentation; nuclear instrumentation; ionizing radiation; radioactivity; neutrons; Neutron-gamma discrimination; plastic scintillator; non-intrusive inspection; beta-rays; gamma-rays; linear accelerator (LINAC); detector

Domaines: Instrumentations et Détecteurs [physics.ins-det]; Physique Nucléaire Expérimentale [nucl-ex]

Pawel Sibczynski, Andrzej Dziedzic, Krystian Grodzicki, Joanna Iwanowska-Hanke, Marek Moszyński, et al.. New perspectives for undoped CaF$_2$ scintillator as a threshold activation neutron detector. EPJ Web of Conferences, 2018, 170, pp.07012. ⟨10.1051/epjconf/201817007012⟩. ⟨cea-01772811⟩