Abstract A first-generation CMOS Charged Particle Spectrometer chip [1] was designed at JPL for flight on the STRV-2 spacecraft. These devices will collect electron and proton spectra in low Earth orbit as part of an experiment to demonstrate Active Pixel Sensor (APS) technology in space. This paper presents the results of total dose testing on these chips and, where possible, attempts to extend the results to other Active Pixel Sensors. I. Introduction CMOS charged particle spectrometers have been proposed [1] as a candidate for measuring space particle environments. These devices, which are a form of Active Pixel Sensor (APS), are fabricated in a standard CMOS process and have a variety of advantages. Integrated analog processing, digital control circuitry and a single 5 V power supply provide easy interfacing, resulting in a compact, powerful instrument. A first-generation CMOS Charged Particle Spectrometer chip, designated CPS32, was designed at JPL for flight on the STRV-2 spacecraft, as part of an experiment to demonstrate APS technology in space. A collection of CPS32 chips will be used to measure the energy spectra of trapped electrons and protons in STRV-2’s low earth orbit, while a pinhole camera will allow simultaneous collection of angular information for low energy electrons. This capability is made possible by the pixellation of the detector, and its easy digital interfacing. During the 1-year mission, these devices will be exposed to an estimated dose of 10 krad (100 Gy), from a mixture of trapped protons and electrons. They will be required to operate at unregulated ambient temperatures, expected to vary between -40°C and +60°C. This paper presents the results of total dose testing of these chips with a Co60 gamma source. Due to funding limitations, we were not able to perform displacement damage testing using protons. However, the results obtained here indicate that the total dose effects will predominate. Where possible, an attempt is made to extend the results to other APS applications. |
