An Avalanche-type X-ray Image Pickup tube with an amorphous selenium (a-Se) photoconductive layer has been investigated. A new face plate technique using a BN face plate and a thin glass plate with an electrode pin is proposed. Defects of reproduced image of the pickup tube can be reduced by the technique. Generation factor of hole-electron pairs from an X-ray photon in this pickup tube reachs up to 10^4.
