A Trigger and Readout Scheme for future Cherenkov Telescope Arrays
  The next generation of ground-based gamma-ray observatories, such as e.g. CTA, will consist of about 50-100 telescopes, and cameras with in total ~100000 to ~200000 channels. The telescopes of the core array will cover and effective area of ~ 1 km2 and will be possibly accompanied by a large halo of smaller telescopes spread over about 10 km2 . In order to make maximum use of the stereoscopic approach, a very flexible inter-telescope trigger scheme is needed which allows to couple telescopes that located up to ~1 km apart. The development of a cost effective readout scheme for the camera signals exhibits a major technological challenge. Here we present ideas on a new asynchronous inter-telescope trigger scheme, and a very cost-effective, high-bandwidth frontend to backend data transfer system, both based on standard Ethernet components and an Ethernet front-end interface based on mass production standard FPGAs. 
G. Hermann, C. Bauer, C. Foehr, W. Hofmann, T. Kihm, F. Koeck