Technologically-enhanced electronic image sensors are used in various fields
as diagnostic techniques in medicine or space applications. In the latter
case the devices can be exposed to intense radiation fluxes over time which
may impair the functioning of the same equipment. In this paper we report the
results of gamma-ray irradiation tests on CMOS image sensors simulating the
space radiation over a long time period. Gamma-ray irradiation tests were
carried out by means of IGS-3 gamma irradiation facility of Palermo
University, based on 60Co sources with different activities. To reduce the
dose rate and realize a narrow gamma-ray beam, a lead-collimation system was
purposely built. It permits to have dose rate values less than 10 mGy/s and
to irradiate CMOS Image Sensors during operation. The total ionizing dose to
CMOS image sensors was monitored in-situ, during irradiation, up to 1000 Gy
and images were acquired every 25 Gy. At the end of the tests, the sensors
continued to operate despite a background noise and some pixels were
completely saturated. These effects, however, involve isolated pixels and
therefore, should not affect the image quality.
Research-grade CMOS image sensors for demanding space applications
