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.
Categories: physics.ins-det