A study of monolithic CMOS pixel sensors back-thinning and their application for a pixel beam telescope

This paper reports results of a detailed study of charge collection and signal-to-noise performance of CMOS monolithic pixel sensors before and after back-thinning to 50 and 40μm. This study shows that neither their noise nor their response to ionising particles has been degraded by the thinning process. The thinned chips have been used to build a pixel beam telescope for the ALS 1.5 GeV e- beam test facility. After alignment, an extrapolation resolution better than 9μm has been measured for a configuration of four equally spaced pixel detector planes