Tracking performance and radiation tolerance of monolithic active pixel sensors

CMOS sensors have been developed at IReS-LEPSI for 3 years for future vertex detectors needing very high granularity and minimal material budget. The first prototypes, made of small arrays of a few thousands of pixels, demonstrated the viability of the technology and its high tracking performances (e.g. signal-to-noise ratio = 20-30, more than 99% detection efficiency, spatial resolution of 1.5 mum). As a consequence, CMOS sensors are now being considered as promising alternatives to existing technologies for various vertex detectors of the coming decade, as well as for numerous other applications in various fields. Important steps were achieved recently in order to further understand the characteristics of this new technology and to continue assessing it for its different application domains: the radiation tolerance of sensors to high neutron fluences were studied and a real-scale prototype, made of arrays of 1 million of pixels, was fabricated. Preliminary results on radiation tolerance and on the performances of the real-scale prototype are presented. (C) 2003 Elsevier B.V. All rights reserved.