Portable digital X-ray and gamma-ray imaging system with pinhole and coded mask collimators

The system is based on combined detector: scintillating plate+image intensifier+CCD matrix. The sensitivity of the detector allows the detection of single photon with energy higher than 60 keV. With pinhole collimator (total field of view is 20/spl times/20 degrees, angular resolution is 1.2 degree) system detects the minimum activity of 7.4 MBq (Cs-137 point source) at 1 m distance in 2 min. and SNR=5. For CsI(TI) scintillator of thickness of 1 mm detector's special resolution is 0.5 mm. The hexagonal URA masks of ranks 6 and 9 are used for coded mask imaging; transparent elements of mask are cylindrical holes of diameter 1.3-2.2 mm (the steps of hexagonal structure are 2-2.5 mm). The images of the same objects obtained with pinhole collimator and coded masks show fivefold increase of sensitivity in last case.