Bernd Reinhold (Max Planck Institut für Kernphysik, Heidelberg)
An extensive calibration of about 500 photomultiplier tubes (PMTs) has been done at MPI-K Heidelberg for the Double Chooz reactor neutrino experiment. The poster describes the experimental setup and gives an overview of the results focusing on charge distributions connected to transit times and after-pulse behavior. After successful completion of this task the setup has become a testbed for the whole chain of Double Chooz electronics. In this setup called "Super Vertical Slice" (SVS) 30 PMTs, several Front-end Electronic modules, Waveform Digitizers and the Level-1 Trigger and Timing System are brought together in one place prior to installation at the Far Detector site. It thereby is the missing link between a single channel "slice" of the detector readout ("vertical slice") and the complete setup at Chooz with 390 Inner Detector PMTs. The SVS has already proven to be very useful in tuning and verifying the Front-end Electronics response. The electronics response in case of very high energy depositions is also being studied. The results obtained hint at the feasibility of using muon-induced isotopes, such as B12 or Michel electrons, for detector calibration, thereby influencing the experiment's calibration strategy in the early phase of data taking. A 30 l barrel with the Gd-loaded Target scintillator is being prepared and will be used to measure scintillator properties together with the realistic electronics in place. A selection of measurement results obtained with the SVS will be presented in this poster.