An overview of the hybrid silicon pixel array tube technology for position-sensitive photon detection

The Imaging Silicon Pixel Array (ISPA)-tube is a new kind of position-sensitive photon detector based on the hybrid technology. It combines the best aspects of image intensification with new possibilities offered by integrated electronics. In the place of the imaging phosphor screen as with conventional image intensifiers, the anode of the ISPA-tube is a matrix of small silicon pixels directly detecting, with a high spatial resolution, electrons emitted by a photocathode. Since the pixels are individually connected to an integrated electronic read-out chip, the tube features high gain, low noise and reaches single-photon sensitivity. This paper gives a brief overview of the ISPA-tube technology and its application fields with particular emphasis on gamma ray imaging. It concludes with the design trends for the next generation of tubes.