Use of standard CMOS pixel imagers as ionizing radiation detectors

The recent developments in the domain of the standard CMOS imagers for visible light, mainly in the reduction of the pixel size, has led us to investigate the suitability of some of these devices as ionizing radiation detectors. A standard 640x480 imager with 5.6x5.6 micrometer pixel size (Micron product type MT9V011) has been characterized with both photons ( ⁵⁵Fe and 8 keV X-ray tube) than charged particles sources ( 500 MeV electrons). The main results obtained are: a small pixel multiplicity (4–5), for the detection of either X-ray or charged particles; a good linearity of the response; a S/N ratio ≫ 30 for a Minimum Ionizing Particle and an estimated sensitivity down to about 2 keV.