Gerrit Berend Gerritsen

An infrared image converter equipped with an array of extrinsic silicon photodetectors

A scanning infrared image converter is described in which the line scanning is performed by sampling of the signals from a one-dimensional array of identical detectors, thus eliminating the need for a fast mechanical line scanning device. Gallium-doped silicon acting as an extrinsic photoconductor at an operating temperature of 4°K has been chosen as a detector material. A temperature resolution of 0.1-0.2°C at a speed of 50 frames/s is obtained with the apparatus. This limitation of the resolution can be ascribed to errors in the gain adjustment of the preamplifiers, the noise equivalent temperature difference of the detectors being much lower than the experimental temperature resolution value.