International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

SM/EN-P11

Tagged Neutrons from Portable Neutron Generator for Detection of High Explosives and Fissile Materials in Cargo Containers

A.A. Ananiev, S.G. Belichenko, E.P. Bogolyubov, O.V. Bochkarev, E.V. Petrov, A.M. Polishchuk, Yu.G. Polkanov, and A.Yu. Udaltsov

All Russian Research Institute of Automatics (VNIIA), Moscow, Russian Federation

Corresponding Author: bogolubov@vniia.ru

Two prototypes of measuring inspection systems created in VNIIA and intended for active interrogation of cargo containers to detect high explosives (HE) and fissile materials (FM) are presented. Both systems are based on 14 MeV tagged neutrons (API) method.

The first system (for HE detection) includes:

  • VNIIA portable neutron generator ING-27 with built-in segmented 9-pixel semiconductor α-detector (30x30 mm2),
  • 12 scintillation γ-detectors based on bismuth germanate crystal (BGO) with size of diam 63x63 mm2,
  • γ-detector shielding from primary neutron flux (borated polyethylene + iron),
  • electronics for data acquisition and processing system.

Experimental results on detection of 50 kg of HE simulator melamine (C3H6N6) are presented for wood and iron matrix as container mock-up with average density of 0.4 g/cm3 and for different distances of HE simulator from container front wall. With increase of distance from container wall to melamine the excess of signal over background decreases. This is conditioned both by measurement geometry and attenuation of probe neutron beam and produced inelastic γ-quanta by container filling. Various decision-making algorithms and improvements are discussed.

The second system (for FMdetection) includes the same neutron generator, six plastic (polystyrene) large square (120x9x9 cm3) scintillators for detection of multiple coincidences of prompt neutrons and fission γ-quanta from FM. Radiation types were distinguished according to time of flight. Measurements were conducted for depleted uranium (8 kg) arranged in container filled with wood and iron of 0.4 g/cm3 average density at the distance of 60 cm from container front wall. Excess of two- and three-fold coincidences from uranium over the corresponding background value was observed both in neutron and γ-channels. The best signal/background ratio was revealed for container filled with iron.


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