Progress towards a high-resolution x-ray photon counter

Progress towards x-ray shot-noise limited imaging with resolution superior to film is reported for a large format amorphous silicon imaging system containing 1536x1920 pixels. Improvements over previous work include the development of a complete system, the use of charge-sensitive amplifiers, and careful control of extrinsic noise. A charge-sensitive amplifier with 1000:1 dynamic range is used to detect the signal in the presence of a large parasitic capacitance, 95pF, which both increases the intrinsic noise in the amplifier and technical noise coupled from other sources. The RMS noise level, 4200 e, is within two octaves of single x-ray counting.