An Analog Trigger System for Atmospheric Cherenkov Telescope Arrays

Arrays of Cherenkov telescopes typically use multi-level trigger schemes to keep the rate of random triggers from the night sky background low. At a first stage, individual telescopes produce a trigger signal from the pixel information in the telescope camera. The final event trigger is then formed by combining trigger signals from several telescopes. In this paper we present a Cherenkov telescope trigger scheme based on the analog pulse information of the pixels in a telescope camera. Advanced versions of all components of the system have been produced and a working prototype has been tested, showing in most cases features which surpass previous designs in terms of compactness, low noise, short delay, low power consumption and flexibility to be adapted to different observation conditions. Finally, issues related to integrating the trigger system in a telescope camera and in the whole array will be dealt with.