Development of Portable SNMs Detection System with D-D Neutron Source based on Combination of Noise Analysis and Threshold Energy Neutron Analysis Method

摘要

Detection of hidden special nuclear materials (SNMs) used for nuclear explosives such as 235 U is important issue for nuclear security to counter terrorist threats. The interrogation systems used in a port and an airport has been developing in the world, and the active neutron-based interrogation system is the one of the candidates for this purpose. We are developing an active neutron-based interrogation system combined with radiation detectors and a D-D neutron source usable in seaports and airports. The D-D neutron source shown in Figs. 1 and 2 is a compact and light-weight portable discharge-type fusion neutron source called IECF (Inertial Electrostatic Confinement Fusion) device [1] . It provides 2.45 MeV mono-energetic neutrons whose production rate is more than 5x10 7 n/s in CW mode without using radioisotope such as tritium. An mportant advantage of IEC comes from the use of "gas target" and this enables stable high-power operation of IEC devices to produce copious amount of D-D neutrons in a compact system. We adopted new Threshold Energy Neutron Analysis (TENA) method and neutron and gamma-ray noise analysis method based on the variance-to-mean value method in the present interrogation system.