Monte Carlo N-Particle simulations of an underwater chemical threats detection system using neutron activation analysis

Abstract

A: In this paper we present Monte Carlo N-Particle (MCNP) simulations of the system for underwater threat detection using neutron activation analysis developed in the SABAT project. The simulated system is based on a D-T neutron generator emitting 14 MeV neutrons without associated α particle detection and equipped with a LaBr 3 :Ce scintillation detector offering superior energy resolution and allowing for precise identification of activation γ quanta. The performed simulations show that using the neutron activation analysis method with the designed geometry we are able to identify γ-rays from hydrogen, carbon, sulphur and chlorine originating from mustard gas in a sea water environment. Our results show that the most efficient way of mustard gas detection is to compare the integral peak ratio for Cl and H.

A new detector concept based on the prompt gamma radiation analysis for In vivo boron monitoring in BNCT

“…Thus, it is often considered as a cheaper and easier-to-operate alternative to semiconductors in many applications, e.g. homeland security ( 18 ) . Drawbacks of this detection material are its hygroscopicity and internal radiation, which may affect detection of low activity samples in the energy range up to almost 4 MeV, especially in the case of large detectors, e.g.…”

Performance of the SABAT Neutron-Based Explosives Detector Integrated with an Unmanned Ground Vehicle: A Simulation Study

“…Thus, neutron-activation-based sensors are still under intense development. One such device has been developed at the Jagiellonian University in Kraków within the SABAT project devoted to the detection of munitions, chemical agents, and heavy fuel oil sunk in the Baltic Sea [5][6][7][8]. A schematic view of the SABAT sensor is presented in Figure 1.…”

“…Neutrons are absorbed or scattered inelastically on nuclei of the investigated object exciting them. The activated nuclei de-excite to the ground state, emitting γ quanta whose energies are characteristic for each isotope [5]. These quanta can be detected by a scintillator or semiconductor detector, which enables the reconstruction of the elemental content of the tested substance and, as a consequence, its identification [6].…”

“…Alternatively, in the case of the pulsed mode of neutron generator, one can register the time of the pulse generation and use it as a start signal for the γ-ray detector. This allows separation of the prompt γ quanta from neutron inelastic scattering from those generated in the capture processes and increases the performance of detection [5]. In the first prototype of the SABAT sensor, we use the CAEN A5202 unit based on two Citiroc-1A chips produced by WeeROC, providing 64-channel readout [14].…”

“…As was mentioned before, as a neutron source, we considered the newest version of the compact and lightweight DT generator by Thermo Fisher Scientific, P-320 [10], providing 10 8 neutrons per second. As in the previous studies, the assumed γ quanta spectrometer is a scintillator detector with a 2" × 2" LaBr 3 :Ce:Sr crystal read out by a photomultiplier tube [5]. The scenario simulated in this work contains a realistic model of the generator and detector installed on the vehicle described at the end of Section 1 operating at different distances from the tested object placed on the ground or buried in the soil at various depths.…”