Gamma ray imaging using a cadmium zinc telluride crystal and micro-channel plates

Cadmium zinc telluride has proven to be a useful crystal for detecting gamma rays. It shows great promise for filling the need for a high energy and spatial resolution detector for gamma ray imaging. One of the challenges for the use of this device is in the storage and readout of the charge produced by the gamma interaction. The current thrust has been to use techniques similar to those developed for infrared detectors, which use a preamplifier and a charge coupled device for each pixel element. We present an alternative readout approach, which activates the back surface of the crystal so that the charge can be liberated into a vacuum. This photocathode device can then be coupled to a micro-channel-plate readout system