Explosive detection system using pulsed 14 MeV neutron source

• Published in: Fusion engineering and design Vol. 85; no. 7; pp. 1562 - 1564
• Main Authors: Sharma, Surender Kumar, Jakhar, Shrichand, Shukla, Rohit, Shyam, Anurag, Rao, C.V.S.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2010; Elsevier
• Subjects: Ammonium nitrate; Applied sciences; Controled nuclear fusion plants; Digital pulse-height spectrum; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Experimental methods and instrumentation for elementary-particle and nuclear physics; Explosive detection; Installations for energy generation and conversion: thermal and electrical energy; Neutron sources; Nuclear physics; Particle sources and targets; Physics; Pulsed neutron source; Ammonium nitrate; Digital pulse-height spectrum; Explosive detection; Pulsed neutron source; Hydrogen; Nitrates; Nitrogen; Carbon; Neutron source; Nuclear fusion reactor; Concentration effect; Bismuth; Pulsed source; Neutron irradiation; Fast neutron; Measurement method; Sampling; Optical fiber
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2010.04.044

The main elements present in the explosives are hydrogen (H), nitrogen (N), oxygen (O) and carbon (C). The elemental density ratios (C/O, N/O, H/N, etc.) of explosives are different from the other substances. The explosives are characterized by low H and C concentration and high N and O concentration. The elemental composition of explosive materials can be found by measuring the γ-rays produced due to the activation of explosive material by 14 MeV neutrons. A pulsed fast neutron system is used for the identification of H, N and O. Ammonium nitrate sample has been irradiated by pulsed 14 MeV neutrons of 10 8 neutrons/pulse and the pulse width less than a microsecond. The material has been irradiated with 5–7 neutron pulse in order to increase the γ-ray count. The resulting γ-ray spectrum due to the activation of ammonium nitrate is recorded and presented in this work. The γ-ray spectrum has been recorded using 3″ × 3″ Bismuth Germanium Orthosilicate (BGO) and fast digitizer with sampling rate of 2 GS/s. The signal is transferred through fiber optic cable to the personal computer for further processing and analyzing. Pulse-height spectrum is constructed through a dedicate MATLAB routine in which the number of energy bins can be kept as per requirement.