Sophisticated online analysis in ADC boards

For the readout of the calorimeter of the WASA-at-COSY experiment a QDC board using flash ADCs and FPGAs to perform the pulse integration was developed. In the initial version only a simple pulse finding algorithm was implemented in order to avoid delay cables by storing the digitized signals in a pipeline of a few microseconds. Recently a new version with 16 ADCs at a sample rate of 240 MHz and 12 Bit resolution was developed for tests of cylindrical drift chambers (straw tubes) in the Straw Tube Tracker of the PANDA experiment. The goal was to measure the energy loss by charge readout in addition to drift time measurement. Due to the irregular cluster structure of the straw signals complex algorithms for pulse finding, pulse feature extraction and triggering were implemented. The algorithm can detect pileup and find pulse groups. Integration is possible over single pulses and over complete groups. Different methods for the calculation of starting time, including constant fraction, are implemented. Internal trigger generation depends on various criteria, e.g. slew rate, amplitude or sum of consecutive samples