Advanced nuclear techniques for humanitarian demining

Nuclear techniques employing neutrons have proved to be a useful tool in the identification of commonly used explosives which present an elevated concentration of nitrogen. Characteristic /spl gamma/-rays emitted in the thermal neutron capture reaction or in the fast neutron inelastic excitation of nitrogen nuclei have been proposed as the signature to identify hidden explosives. Compared to the other proposed non-nuclear techniques, the nuclear sensor is the only one allowing to discriminate mines from other underground objects. The present challenge is to conceive a cost-effective, mobile detection system based on nuclear techniques which can be operated, in connection with other non-nuclear sensors, by non-specifically trained personnel in field conditions. We have started a detailed study to conceive a mobile system to detect small quantities of hidden explosives using modern technology in order to improve the overall effectiveness from the point of view of efficiency, costs and transportability. To this end we are proceeding to test a number of CsI(Tl) scintillators assembled with a photodiode readout and dedicated surface mounted fast front-end electronics. We are testing neural-network based decision algorithms for on-line analysis of the signals. Finally we are planning to test a mixed (thermal and fast neutron) technique in order to reduce both the scanning time and the false alarm rates.