A gamma, x-ray and high energy proton radiation-tolerant CIS for space applications

Photon counting is useful in space-based imagers wherever quantitative light-intensity evaluation is necessary. Various types of radiation, from cosmic rays to high-energy proton beams to gamma radiation, have an effect on the functionality and accuracy of imagers and the literature is extensive [1,2]. Techniques to maximize sensor tolerance have also been developed for a number of years and several imagers resistant to up to 30Mrad (Si) of gamma radiation have been reported. These sensors have several shortcomings: either significant noise performance degradation, up to several orders of magnitude [2], or unacceptably high pre-radiation noise levels [3]. In addition, many radiation-tolerant sensors use dedicated processes, thus possibly limiting their suitability for mass-market applications [4].

Photon counting is useful in space-based imagers wherever quantitative light-intensity evaluation is necessary. Various types of radiation, from cosmic rays to high-energy proton beams to gamma radiation, have an effect on the functionality and accuracy of imagers and the literature is extensive [1], [2]. Techniques to maximize sensor tolerance have also been developed for a number of years and several imagers resistant to up to 30Mrad (Si) of gamma radiation have been reported. These sensors have several shortcomings: either significant noise performance degradation, up to several orders of magnitude [2], or unacceptably high pre-radiation noise levels [3]. In addition, many radiation-tolerant sensors use dedicated processes, thus possibly limiting their suitability for mass-market applications [4].