Studying the response of a novel Hexagonal Boron Nitride Solid State neutron detector with Geant4

Nuclear nonproliferation is one of the pillars of nuclear safety. To prevent the acquisition of unauthorized nuclear material, new technology for its early detection must be created. One way to do so is by measuring the neutrons emitted by some radioactive isotopes. Graphene hexagonal Boron Nitride (GhBN), is being proposed as a novel material in the use of solid state neutron detectors. GhBN comprises layers of hexagonal boron nitride encapsulating a layer of graphene. The boron nitride serves to act as a very effective neutron trap, where the 10B isotope traps slow neutrons, following the nuclear reaction: 10B + n –> 4He + 7Li. Both daughter particles,4He and 7Li, then ionize atoms in the hBN layer creating an electron-hole pair that could be drifted to an electrode under an electric field. Geant4 Monte Carlo simulations of the GhBN detector were performed in this work, which showed a detector efficiency consistent with values reported in the literature for scalable hexagonal boron nitride. Polymethyl methacrylate (PMMA) was layered on top of the GhBN to moderate high energy neutrons; simulations showed that a thickness of 10mm was effective at increasing the efficiency of the detector at higher neutron energies, >1.0 MeV, and resulted in minor increases to efficiency for all neutron energies between 0.0253 eV and 18 MeV. To simulate a possible advanced geometry for the novel neutron detector, GhBN and PMMA were then layered to determine the effective limit of efficiency increase, which showed the most effective geometry being 5 layers each of GhBN and PMMA. In this contribution, we are going to show the results of the simulation work, which will contribute to the determination of the final, optimal design for this novel detector.