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CTA - Abteilung Hofmann
Abstract:
The Cherenkov Telescope Array (CTA) is the next generation ground-based observatory for
gamma-ray astronomy that will reach a performance unprecedented in the field. This thesis
focuses on optimising this performance in the core energy range of CTA around 1TeV. In a
first part, the wavelength-dependent angular efficiency of light concentrators for the camera
system FlashCam, proposed for the medium size telescopes of CTA, is determined with a
dedicated test system. For hexagonal concentrators with three reflective coatings a signalto-
noise ratio enhancement of 2.2 compared to a camera without concentrators is observed.
By varying the distance between concentrators and photo-sensors, a fine-adjustment of the
angular efficiency increases this ratio by another 3%-5%.
In a second part, the angular resolution and the sensitivity of CTA are studied by means
of simulations. By optimising different quality selection cuts on telescope data, sensitivity
enhancements of 20%-40% compared to the CTA requirements are reached and 30%-40%
for the angular resolution. With the optimised cuts, spatially extended emission models of
the radio galaxy Centaurus A are investigated and it is found that the optimised angular
resolution of CTA allows for different theoretical emission models to be discriminated based
on the predicted emission regions.
