Two-Dimensional Silicon Vidicon Astronomical Photometer

We have developed and successfully used an integrating two-dimensional silicon diode array vidicon photometer which is exceptionally well suited for use with telescopes. The video signal is read out from the 1-cm silicon target of the vidicon through a current mode preamplifier and then converted to digital form and stored on magnetic tape. The 256 x 256 element frames are recorded at 20,000 eight-bit words/sec. The vidicon tube has a published quantum efficiency ranging from 85% at 0.5 micro to 6% at 1.1 micro and must be cooled to about -65 degrees C to eliminate thermal dark current. The minimum detectable signal in the present system is about 1000 carriers per resolution element, limited by preamplifier and other system noise. The system is used as a single-frame camera. The large dynamic range (>10(3)), linear response, high quantum efficiency over a large spectral region, and low cost of the system make it well suited for digital direct image and spectroscopy as well as for a laboratory digitizer of two-dimensional m terial.