Abstract: A large area solid state x-ray detector employs a number of photodiodes that are charged electrically then discharged by exposure to x-ray. Ghost images resulting from release of charge trapped in photodiodes during prior exposures are eliminated by adjusting the biasing during a reset portion of the imaging cycle. Biasing may be increased to decrease the recharge time or reversed in polarity to evenly discharge the diodes or decreased to preserve the offset so that it may be removed from subsequent images by image processing.

Abstract: A large area solid state x-ray detector employs a plurality of cells arranged in rows and columns composed of photodiodes that are charged, exposed to x-rays which deplete their charge in proportion to the exposure, and then recharged to determine the amount of exposure. Fast scanning of the photodiodes consistent with the reduction of dark current effects is obtained without ghost images by employing a non-imaging scan following the imaging scan. The non-imaging scan employs a greater proportion of each scan duration for charge restoration than the imaging scan. In one embodiment simultaneous non-imaging recharging of the photodiodes is performed to substantially reduce this non-imaging time.