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The disk spread function of flare of an x-ray image intensifier (XRII) was measured using monoenergetic x rays. The signal-to-noise ratio at the center of the disks and the pulse height spectrum of the flare are also measured. These measurements are correlated with the physical construction of the XRII. A simple model of the XRII is developed which is used to identify the various sources of flare.

Conventional 2D photodiodes used in multislice CT detectors impose a limitation on the number of slices that can be achieved. The limitations encountered are in the number of metal lines that can be run between photodiode elements without significantly reducing the photodiode active area and in the density of wirebonds that can be accomodated at the edge of the chip. In addition, the photodiodes cannot easily be tiled in two directions due to the need for wirebonding on at least one edge. We have developed a 2D back illuminated photodiode array for multislice CT that overcomes the above limitations. The light sensitivity, sensitivity profiles, risetime, crosstalk, linearity and shunt resistance of the back illuminated photodiodes have been evaluated. The results show that these parameters either meet or exceed the specifications required for CT. The back illuminated photodiode represents an enabling technology for truly large area CT detection systems.