The MuPix system-on-chip for the Mu3e experiment

Mu3e is a novel experiment searching for charged lepton flavor violation in the rare decay mu(+) -> e(+)e(-)e(+). Decay vertex position, decay time and particle momenta have to be precisely measured in order to reject both accidental and physics background. A silicon pixel tracker based on 50 mu m thin high voltage monolithic active pixel sensors (HV-MAPS) in a 1 T solenoidal magnetic field provides precise vertex and momentum information. The MuPix chip combines pixel sensor cells With integrated analog electronics and a periphery with a complete digital readout. The MuPix7 is the first HV-MAPS prototype implementing all functionalities of the final sensor including a readout state machine and high speed serialization with 1.25 Gbit/s data output, allowing for a streaming readout in parallel to the data taking. The observed efficiency of the MuPix7 chip including the full readout system is >= 99% in a high rate test beam. (C) 2016 Elsevier B.V. All rights reserved.