Adaption of an FPGA-based Sampling-ADC for the Crystal Barrel Calorimeter

The digitization stage of the main electromagnetic calorimeter of the CBELSA/TAPS experiment in Bonn (Germany) is being equipped with 80MS/s, 14 bit sampling-ADCs (SADCs), which were adapted from a prototype for the PANDA experiment. Onboard data processing with FPGAs allows determination of the signal characteristics, reducing the data volume substantially. The optional readout of the unprocessed sampled waveforms allows offline analysis and refinement of the FPGA algorithms. A partial setup has shown promising results during a photoproduction-beamtime. It has been demonstrated that the readout-rate limitation of the current QDC readout can be overcome. The full setup is planned to be commissioned within the next year. This paper will present an overview of the SADC project. After an introduction of the CBELSA/TAPS experiment, the new SADC readout will be motivated, followed by its technical specifications and the setup in the experiment. An outline of the firmware and findings from first tests conclude the paper.