ICCD Sensitivity Investigation.

Abstract : The sensitivity of an Intensified Charge Coupled Device (ICCD) utilizing a CCD to detect photoelectrons has been evaluated for operating conditions anticipated in space applications. Data processing techniques for signal discrimination have been identified and evaluated using simulated star scanning measurements and estimated signal and background (zodiacal light) intensities. Since the ICCD is capable of detecting single photoelectrons with a high signal-to-noise ratio, the practical sensitivity is limited by the intensity of background light. The background produces signals which occasionally exceed the detection threshold in the absence of a target. The rate of these 'background events' has been calculated for various conditions and found to be acceptably low even for detection of relatively faint objects (visual magnitude, m(v) = 8) with a high detection probability (99%) in quite intense backgrounds (up to -1.2 stellar magnitudes per square degree) corresponding to the zodiacal light at about 10 degrees from the sun, provided that scattering and diffraction of sunlight at 10 deg off axis is less than -1.2 m(v).