Characterization study of an intensified complementary metal–oxide–semiconductor active pixel sensor

Abstract

An intensified CMOS active pixel sensor (APS) has been constructed for operation in low-light-level applications: a high-gain, fast-light decay image intensifier has been coupled via a fiber optic stud to a prototype "VANILLA" APS, developed by the UK based MI3 consortium. The sensor is capable of high frame rates and sparse readout. This paper presents a study of the performance parameters of the intensified VANILLA APS system over a range of image intensifier gain levels when uniformly illuminated with 520 nm green light. Mean-variance analysis shows the APS saturating around 3050 Digital Units (DU), with the maximum variance increasing with increasing image intensifier gain. The system's quantum efficiency varies in an exponential manner from 260 at an intensifier gain of 7.45 × 10(3) to 1.6 at a gain of 3.93 × 10(1). The usable dynamic range of the system is 60 dB for intensifier gains below 1.8 × 10(3), dropping to around 40 dB at high gains. The conclusion is that the system shows suitability for the desired application.