MCNPX simulation and experimental tests of the tagged neutron system for explosive detection in walls
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MCNPX simulation and experimental tests of the tagged neutron system for explosive detection in walls Hui Xue1 · Cong Li1 · Ya‑Dong Gao1 · Shi‑Wei Jing1,2,3 · Yu‑Lai Zheng2 Received: 18 March 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract An experimental detection system based on tagged neutron method was developed for detecting the explosives embedded in a concrete wall. The simulant samples of TNT and ammonium nitrate were tested by this system under different conditions. The experimental results were compared with the MCNPX code simulation results and have good consistency. On this basis, the simulation of RDX and Tetryl explosives hidden in different thickness walls was carried out. The simulation results show that the experimental system can detect the 300 g explosive hidden in a wall with a thickness of no more than 10 cm by using the ratio of delta and its standard deviation. Keywords Tagged neutron · Explosive in a wall · MCNPX · Standard deviation
Introduction Terrorist activities are the most important national security risk for many countries, which threatens the life security of a country’s people. Explosive attack, a common means of terrorists, has made countries attach great importance to explosive detection in recent years. X-ray imaging technology or gamma-ray scanners are often used to detect packages or luggage at checkpoints, airports, etc. [1]. X-ray or gammaray method is satisfactory for the determination of the shape and density of the inspected substance, but it cannot analyze the chemical elements of the inspected substance. Detection systems based on tagged neutron (TN) technology have been actively developed [2–4]. This technology is the use of T (d, n) α fusion reaction to produce a 14 MeV neutron and an alpha particle, which is emitted almost back to back. The detection of alpha by a position sensitive charged-particle detector determines the direction of the alpha particle and thus the direction (and emission time) of the corresponding * Shi‑Wei Jing [email protected] 1
College of Physics, Northeast Normal University, Changchun 130024, Jilin, China
2
China Institute of Atomic Energy, Beijing 121000, China
3
Key Laboratory of Sichuan Higher Education—Criminal Science and Technology Laboratory (Sichuan Police College), Luzhou 646000, Sichuan, China
neutron. The time of flight (TOF) of alpha particles and neutrons is determined by the alpha-gamma coincidence time. The neutron direction and TOF allows to focus the inspection on a specific volume, and perform inspections on the items contained in the volume. Compared with X-ray scanners, TN technology can measure local volumes and provide information on the elemental composition of irradiated items [5–7], greatly enhancing the recognition ability. This makes the technology become an important new research field. It is possible for terrorists to take the opportunity to hide the explosives inside the building’s concrete wall during the construction of the building, thereby destroying it. Although the probabilit
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