A TDC for the characterization of KM3NeT PMTs

The optical modules of the future KM3NeT neutrino telescope will contain many photomultiplier tubes with a diameter of about 3 in. In order to characterize these photomultiplier tubes, a 16 channel Time-Over-Threshold TDC with a GigaBit Ethernet communication channel has been built in an Altera StratixIV evaluation board. The TDC data is packed in UDP packages and sent to the host PC. Control is implemented using I2C command packages send to the TDC by the host PC. After execution of I2C commands a result package is send back to the host. We will present the TDC setup and first results.