Trace explosives detection for finding landmines

Trace Explosive Detectors (TED) technologies have been investigated as a means of confirming the presence of a landmine at a given location. A field trial was performed with a landmine detector prototype based on Ion Mobility Spectrometry. The system was based on the detection of the explosives in soil and had a detection limit of 0.4 ppb w/w for TNT and 7.4 ppb why for RDX. The minefield was composed of 51 sites on wich the detector performance was evaluated. For most freshly buried sites it was found that the level of explosive was below the detection limit of the prototype. In addition, a quantitative analysis of the residual explosive transfer to the soil by hands was performed. Results showed that the level transfered by hands was in most cases below 0.1 ppb for TNT and at 0.8 ppb w/w or below for RDX. However, it was found that the explosive level contained in the soil increased with time to a level around 2-8 ppb w/w for TNT, ten month after the landmine burial. These rough tests have yielded some preliminary results concerning the level of explosives detectable after the burial of landmines and the dynamics of the explosive level build up in the soil with time.