  We report on the construction, operation experience, and preliminary
background measurements of an InGrid detector, i.e. a MicroMegas detector with
CMOS pixel readout. The detector was mounted in the focal plane of the Abrixas
X-Ray telescope at the CAST experiment at CERN. The detector is sensitive to
soft X-Rays in a broad energy range (0.3--10 keV) and thus enables the search
for solar chameleons. Smooth detector operation during CAST data taking in
autumn 2014 has been achieved. Preliminary analysis of background data
indicates a background rate of $1-5\times
10^{-5}\,\mathrm{keV}^{-1}\mathrm{cm}^{-2}\mathrm{s}^{-1}$ above 2 keV and
$\sim 3\times 10^{-4}\,\mathrm{keV}^{-1}\mathrm{cm}^{-2}\mathrm{s}^{-1}$ around
1 keV. An expected limit of $\beta_\gamma \lesssim 5\times 10^{10}$ on the
chameleon photon coupling is estimated in case of absence of an excess in solar
tracking data. We also discuss the prospects for future operation of the
detector.
