Neutron activation and analyses

Detection of abandoned land mines is a difficult problem. The only true mine detection systems in the inventory are based on visible and infra-red observation, on metal detection, on microwave detection, and on nuclear techniques. Each of these systems is able to detect a mine from one of its characteristics, i.e. presence of antennas or trigger wires, or presence of a metallic detonator, or anomalies in microwaves backscattering properties of a soil with a mine. The interest of nuclear techniques is related to their capability to detect in depth, and their capability to recognize sensitive elements of the explosives in the mines, such as nitrogen. A few nuclear methods are of interest: it is required to detect all the explosive constituents of the mines, to analyse roughly their relative concentrations, and to compare them with reference data from a database. Taking these requirements into account, in addition to more operational considerations, we have selected and tested the more efficient way to detect the sensitive elements of the explosives hidden in the soil. Fast and thermal neutron interrogation analysis (FNA+TNA) has been qualified in our laboratories as a powerful close distance method for identifying the presence of an explosive, from all of its sensitive elements: carbon, nitrogen, oxygen, hydrogen, etc. A ground mobile mine detection system would be designed, with a multisensor detection equipment including cameras, microwave sensors, metallic sensors, and FNA/TNA sensor