Monolithic active pixel sensors for a linear collider

A new generation of semi-conducting pixel sensors for detecting minimum ionising particles (m.i.p.) was designed and first prototypes were fabricated in a standard CMOS technology, guided by the very high vertex detector performances demanded in future collider experiments. The device architecture resembles CMOS cameras, a recent alternative to CCD sensors for visible light imaging. The performances of the first prototype of Monolithic Active Pixel Sensors (MAPS), called MIMOSA, were evaluated with high energy π− beams at CERN. Preliminary test results demonstrate that the sensors detect m.i.p.s with very high efficiency and signal-to-noise ratio and provide excellent spatial resolution.