The CTA Instrument
An artists impression of the Cherenkov Telescope Array. Source G. Perez, SMM, IAC
Current systems of Cherenkov telescopes use at most four telescopes, providing best stereo imaging of particle cascades over a very limited area, with most cascades viewed by only two or three telescopes. An array of many tens of telescopes will allow the detection of gamma-ray induced cascades over a large area on the ground, increasing the number of detected gamma rays dramatically, while at the same time providing a much larger number of views of each cascade. This results in both improved angular resolution and better suppression of cosmic-ray background events.
In a possible design scenario, the southern hemisphere array of CTA will consist of three types of telescopes with different mirror sizes in order to cover the full energy range. The northern hemisphere array would consist of the two larger telescope types.
- The low energy instrumentation will consist of a few 24 metre-class telescopes with a moderate field of view (FoV) of the order of 4-5 deg.
- The medium energy range, from around 100 GeV to 1 TeV, will be covered by telescopes of the 10-12 metre class with a FoV of 6-8 degrees.
- The high energy instruments, operating above 10 TeV, will consist of a large number of small (4-6 metre diameter) telescopes with a FoV of around 10 degrees