Wuppertal 2015 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 31: Dunkle Materie II
T 31.1: Gruppenbericht
Montag, 9. März 2015, 16:45–17:05, K.11.24 (HS 33)
Operation of an InGrid based X-ray detector at the CAST experiment — •Christoph Krieger, Klaus Desch, Jochen Kaminski, and Michael Lupberger — Physikalisches Institut, Universität Bonn, Nußallee 12, 53115 Bonn
The CERN Axion Solar Telescope (CAST) is searching for axions and other new particles emerging from the Sun and coupling to photons. Those particles are converted into soft X-ray photons in a high magnetic field. To enhance sensitivity for physics beyond the Standard Model it is necessary to cope with weak couplings and low energies, thus requiring an efficient background discrimination as well as a detection threshold below 1 keV.
Both requirements are fulfilled by an X-ray detector based on the combination of a Micromegas gas amplification stage with a highly integrated pixel chip (InGrid) which allows to make full use of the Micromegas structure’s granularity. The necessary precision in fabrication is achieved by the use of photolithographic postprocessing techniques. The high spatial resolution allows for a topological suppression of background events originating from cosmic rays as well as for the low detection threshold as single electrons can be detected.
After the detector’s energy threshold was evaluated at an X-ray generator to be low enough to allow for the detection of the carbon Kα line at 277 eV, the detector was mounted at one of CAST’s X-ray telescopes and installed along with the necessary infrastructure in 2014.
The data taken during the CAST run 2014 is being analysed. Background studies and rates will be presented as a first result.