Editing CERN Axion Solar Telescope (section)

=== X-ray telescope with a charged couple device (CCD) ===
This detector has a pn-CCD chip located at the focal plane of the X-ray telescope. The X-ray telescope is based on the popular Wolter-I mirror optics concept. This technique is widely used in almost all [[X-ray astronomy]] telescopes. Its mirror is made up of 27 gold-coated nickel shells. These parabolic and hyperbolic shells are [[Confocal paraboloidal coordinates|confocally]] arranged to optimize the resolution. The largest shell is 163&nbsp;mm in diameter, while the smallest is 76&nbsp;mm. The overall mirror system has a focal length of 1.6&nbsp;m.<ref name=":3" /><ref>{{Cite thesis|title=Search for Solar Axions with the CCD Detector and X-ray Telescope at CAST Experiment|url=https://cds.cern.ch/record/2023683?ln=en|publisher=TUPrints ULB|date=2015|place=Darmstadt, Germany|first=Madalin Mihai|last=Rosu}}</ref> This detector achieved a remarkably good signal to noise ratio by focusing the axions created inside the magnetic field chamber onto small, about few <math>mm^2</math> area.<ref name=":1" />