The perturbation of backscattered fast neutrons spectrum caused by the resonances of C, N and O for possible use in pyromaterial detection

• Main Authors: Abedin, Ahmad Firdaus Zainal, Ibrahim, Noorddin, Zabidi, Noriza Ahmad, Abdullah, Abqari Luthfi Albert
• Format: Conference Proceeding
• Language: English
• Subjects: ABSORPTION; Absorption cross sections; Americium; BACKSCATTERING; Beryllium; CARBON; CHEMICAL EXPLOSIVES; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Computer simulation; COMPUTERIZED SIMULATION; CROSS SECTIONS; Cylinders; Detectors; ENERGY SPECTRA; FAST NEUTRONS; HE-3 COUNTERS; Helium; Helium isotopes; HYDROGEN; Land mines; Mine detection; Mine detectors; MONTE CARLO METHOD; NEUTRON DETECTION; NEUTRON SOURCES; Neutrons; NITROGEN; OXYGEN; Polyethylene; POLYETHYLENES; Sensors; THERMAL NEUTRONS
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.4916853

Neutron radiation is able to determine the signature of land mine detection based on backscattering energy spectrum of landmine. In this study, the Monte Carlo simulation of backscattered fast neutrons was performed on four basic elements of land mine; hydrogen, nitrogen, oxygen and carbon. The moderation of fast neutrons to thermal neutrons and their resonances cross-section between 0.01 eV until 14 MeV were analysed. The neutrons energies were divided into 29 groups and ten million neutrons particles histories were used. The geometries consist of four main components: neutrons source, detectors, landmine and soil. The neutrons source was placed at the origin coordinate and shielded with carbon and polyethylene. Americium/Beryllium neutron source was placed inside lead casing of 1 cm thick and 2.5 cm height. Polyethylene was used to absorb and disperse radiation and was placed outside the lead shield of width 10 cm and height 7 cm. Two detectors were placed between source with distance of 8 cm and radius of 1.9 cm. Detectors of Helium-3 was used for neutron detection as it has high absorption cross section for thermal neutrons. For the anomaly, the physical is in cylinder form with radius of 10 cm and 8.9 cm height. The anomaly is buried 5 cm deep in the bed soil measured 80 cm radius and 53.5 cm height. The results show that the energy spectrum for the four basic elements of landmine with specific pattern which can be used as indication for the presence of landmines.