International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

Monte Carlo Modelling of Fast Neutron Scattering by Various Compounds in View
of Elaboration of a Single Shot Inspection System

U. Wiacek¹, K. Drozdowicz¹, B. Gaba´nska¹, V.A. Gribkov², and R. Miklaszewski³

¹The Henryk Niewodnicza´nski Institute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland
²Institute for Theoretical and Experimental Physics, Moscow, Russia
³Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland

Corresponding Author: rysiek@ifpilm.waw.pl

Modern, portable or transportable neutron generators, based on the Plasma-Focus principle, are capable to produce a flash of the very intense (up to 109 of 2.45 MeV neutrons from D–D and up to 1011 of 14 MeV neutrons per shot from D–T reactions) and very short neutron pulses (10 ns). Taking advantage of these capabilities it is possible to determine the elemental content of unknown samples from information existing in a field of scattered neutrons. It allows proposing an alternative approach to the detection of explosives and other illicit materials. The time–of–flight method can be involved in the identification procedure due to the short neutron pulse duration. It is expected that a single shot inspection system can be elaborated on the basis of the proposed method, limited in time only by computer data processing.

Results of the Monte Carlo simulations of the scattered neutron field from several compounds (explosives and everyday use materials) are presented in the paper. The MCNP5 code has been used to get info on the angular and energy distributions of neutrons scattered by the above mentioned compounds assuming the initial neutron energy equal to 2.45 MeV (D–D). A new input has been elaborated that allows modeling not only a spectrum of the neutrons scattered at different angles but also their time history from the moment of generation up to detection. Such an approach allows getting approximate signals as registered by hypothetic scintillator+photomultipler probes placed at various distances from the scattering object, demonstrating a principal capability of the method to identify an elemental content of the inspected objects.

Full text paper