Photon Counting Using Microchannel Plate Intensified Electrographic Cameras

Abstract

Electrography has proven to be a useful tool for astronomical and aeronomical investigations. The addition of microchannel plate intensification provides significant enhancements in responsivity and resolution and offers the potential of providing detection of single photon events. In practice, long exposures and film fog have precluded the use of this kind of detector as a photon counting device. For low light levels or short exposures, it is possible with the correct algorithm to separate individual photon events from the film fog. This has several advantages including increased low light sensitivity, increased photometric accuracy, and increased resolution. A computer algorithm has been developed and applied to microchannel plate intensified electrographic emulsions to identify and centroid individual photon events. Modifications of this algorithm which treat the case of occasional overlap of photon events are discussed. This algorithm is very general and can be applied to other imaging detection techniques and can be used to analyze starfields in conventional astronomical photography.