Field tests of X-ray backscatter mine detection

The implementation of a backscattered X-ray landmine detection system has been demonstrated. The next step was to evaluate the modality by assembling a system for field work. To assess the system's response to a variety of objects, buried plastic and metal antitank landmines, surface plastic antipersonnel landmines, and surface metal fragments were used as targets. The location of the test site was an unprepared field. The X-ray machine used for the field test system was an industrial X-ray machine which was operated at 150 kV and 5 mA and collimated to create a 2 cm diameter X-ray spot on the soil. The detectors used were two plastic scintillation detectors: one collimated to respond primarily to photons that have undergone multiple collision and the other uncollimated to respond primarily to photons that have had only one collision. To provide motion, the system was mounted on a gantry and rastered side-to-side using a computer-controlled stepper motor with a come-along providing the forward movement. Data generated from the detector responses were then analyzed to provide the images and locations of landmines. A new analysis method that increases resolution was used. Changing from the lab environment to the field did not decrease the system's ability to detect buried or obscured landmines. The addition of rain, blowing dust, rocky soil and native plant-life did not lower the system's resolution or contrast for the plastic or the metal landmines. Concepts for a civilian mine detection system based on this work using commercial off the shelf (COTS) equipment were developed.