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This paper presents test-beam results of monolithic pixel detector prototypes fabricated in 200 nm Silicon-On-Insulator (SOI) CMOS technology studied in the context of high spatial resolution performance. The tested detectors were fabricated on a 500 μ m thick high-resistivity Floating Zone type n (FZ-n) wafer and on a 300 μ m Double SOI Czochralski type p (DSOI Cz-p) wafer. The pixel size is 30 μ m × 30 μ m and two different front-end electronics architectures were tested, a source follower and a charge-sensitive preamplifier. The test-beam data analyses were focused mainly on determination of the spatial resolution and the hit detection efficiency. In this work different cluster formation and position reconstruction methods are studied. In particular, a generalization of the standard η -correction adapted for arbitrary cluster sizes, is introduced. The obtained results give in the best case a spatial resolution of about 1.5 μ m for the FZ-n wafer and about 3.0 μ m for the DSOI Cz-p wafer, both detectors showing detection efficiency above 99.5%. [ABSTRACT FROM AUTHOR]

The ultra-thin and highly granular CMOS Monolithic Active Pixel Sensors (MAPS) are typically optimized for high rate high precision tracking, which implies the use of a very thin active medium and digital readout. Both features hamper using the devices for identifying low momentum particles by means of dE/dx. Still, MAPS feature charge sharing and typically clusters of more than one fired pixel per impinging particles are formed. It was previously shown that the number of fired pixels per cluster scales with the dE/dx, which allowed identifying highly ionizing nuclear fragments [1]. Assuming a sufficiently strong response to different dE/dx, this approach could also be considered for distinguishing minimum ionizing particles (MIP) from light fragments like alpha particles in tracking detectors. In this work, we study this response with particle beams with a dE/dx of up to four times the ones of MIPs, for non-irradiated and irradiated chips, with different sensing nodes as implemented in the MIMOSIS-1 prototype used for the vertex detector of the CBM experiment. [ABSTRACT FROM AUTHOR]