The Mu3e experiment is searching for the charged lepton flavour violating decay $ mu^+rightarrow e^+ e^- e^+ $, aiming for an ultimate sensitivity of one in $10^{16}$ decays. In an environment of up to $10^9$ muon decays per second the detector needs to provide precise vertex, time and momentum information to suppress accidental and physics background. The detector consists of cylindrical layers of $50, mutext{m}$ thin High Voltage Monolithic Active Pixel Sensors (HV-MAPS) placed in a $1,text{T}$ magnetic field. The measurement of the trajectories of the decay particles allows for a precise vertex and momentum reconstruction. Additional layers of fast scintillating fibre and tile detectors provide sub-nanosecond time resolution. The MuPix8 chip is the first large scale prototype, proving the scalability of the HV-MAPS technology. It is produced in the AMS aH18 $180, text{nm}$ HV-CMOS process. It consists of three sub-matrices, each providing an untriggered datastream of more than $10,text{MHits}/text{s}$. The latest results from laboratory and testbeam characterisation are presented, showing an excellent performance with efficiencies $>99.6,text{%}$ and a time resolution better than $10, text{ns}$ achieved with time walk correction.
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