f . .---1 . -A continuously operating, scanning x-ray machine is being developed for landmine detection using backscattered x-rays. The source operates at 130 kV and 650 mA. The x-rays are formed by electrons striking a high Z target. Target shape is an approximate 5 cm wide by 2 10 cm long racetrack. The electron beam is scanned across this targit with electromagnets. There are 105, I-cm by I-cm collimators in each leg of the racetrack for a total of 210 collimators. The source is moved in the

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... forward direction (the direction perpendicular to the 210-cm dimension) at 3 mi/h. The forward velocity and collimator spacing are such that a grid of collimated x-rays are projected at normal incidence to the soil. The spacing between the collimators and the ground results in a 2-cm by 2-cm x-ray pixel on the ground. A unique detector arrangement of collimated and uncollimated detectors allows surface features to be recognized and removed, leaving an image of a buried landmine. Another detector monitors the uncollimated x-ray output and is used to normalize the source output. The mine detector is being prepared for an Advanced Technology Dkmonstration (ATD). The ATD is scheduled for midyear of 1998. The results of the source performance in pre AXD tests will be presented. --.--