Ultra-Fast Sampling and Data Acquisition Using the DRS4 Waveform Digitizer

Ultra-fast sampling through flash A/D converters is expensive and power consuming. Switching capacitors arrays are a valid alternative, combining good sampling performance to relatively low cost and power consumption. In this work we describe a 1152 channels readout system based on the DRS4 ultra-fast analog sampler, operated at 2GS/s sampling frequency. This type of readout is particularly suitable for Cherenkov telescopes, where a large number of channels (pixels) need to be sampled at ultra-fast sampling speed to catch the short-lasting Cherenkov flashes. This digitization system was successfully installed in the MAGIC telescopes during its major upgrade. We discuss the design of the electronics and the measured performance of the system.