  A new downstream tracking system, known as the Mighty Tracker, is planned to
be installed at LHCb during LS4 of the LHC. This will allow an increase in
instantaneous luminosity from $2\cdot10^{33}~\mathrm{cm}^{-2}\mathrm{s}^{-1}$
to $1.5\cdot10^{34}~\mathrm{cm}^{-2}\mathrm{s}^{-1}$ and therefore an overall
higher irradiation and up to six times higher occupancy. To keep the material
budget as low or even lower as for the current detector, the Mighty Tracker is
planned as a hybrid system with silicon pixels in the inner and scintillating
fibers in the outer region. For the pixel detector part HV-CMOS MAPS with a
pixel size of $55~\mathrm{x}~165~\mathrm{\mu m^2}$ will be used. This
technology has been chosen because of its low production costs, low material
budget, high radiation tolerance and good timing resolution. To fulfill the
requirements, the development and characterization of the sensors focuses on
radiation damage with fluences up to
$2\cdot10^{15~}\mathrm{MeVn_{eq}}/\mathrm{cm^2}$ and a timing resolution
$\leq3~\mathrm{ns}$. The timing resolution is restricted due to the
$40~\mathrm{MHz}$ trigger-less DAQ by LHCb. To characterize and further develop
the MightyPix a new readout system called MARS (Mighty TrAcker Readout System)
has been developed. MARS is a modular system, able to test different single
chips in the laboratory as well as at testbeam facilities. It has been used to
perform first characterization studies of development-chips investigating
radiation tolerance and timing resolution as well as the dependence of the
sensor settings on the overall performance.
