Inspecting Minefields and Residual Explosives by Fast Neutron Activation Method

As an upgrade of a robotic mobile system for anti-personnel landmine clearance, a fast neutron probe has been considered for the detection of mines and explosive residues. Laboratory tests were made by using the 14 MeV $6\times 10^{7}$ neutrons/sec beams with the associated alpha particle detection and with a ${\rm LaBr}_{3}$ gamma-ray detector. Simulant of the anti-personnel mine was used as a target. Several measurements were made with the target buried into the soil at different depths. For each depth minimal time measurement was estimated for false negative 0.4% and false positive equal to 10%. Tests showed that it is possible to detect buried landmines as well as residual explosives; however, in order to reach the optimal speed of 10 cm/s of the demining vehicle it is necessarily to use several sealed tube neutron generators and few dozen of ${\rm LaBr}_{3}$ gamma-ray detectors.