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Publisher Summary This chapter examines the improvements to an image intensifier for a γ-ray scintillation camera. A 35 cm input field image intensifier tube designed for scintillation cameras was described at the Fifth Symposium on Photo-Electronic Image Devices. This tube had a photon gain of about 100 and the energy resolution was 20%. Γ-rays travel through a collimator, then impinge on a scintillator that is in contact with the input faceplate of a demagnifying high gain image intensifier. Because of the thickness of the scintillator and of the input faceplate, a diffused spot of light is generated on the photocathode producing a correspondingly diffuse image on the output screen. The requirements of spatial resolution and high counting rate are linked to the temporal response and gain of the tube. The position of the center of the scintillation may be determined by using several photomultipliers. It is found that a counting rate of 105 s−1 can be achieved. Two tubes have been studied both having fast response, compactness, and allowing simple electronic localization using only 3 or 4 photomultiplier tubes. It is observed that the two stage image tube is a high performance tube, allowing good energy resolution and high spatial resolution. |
