Dynode-timing method for PET block-detectors

The focus of this paper is the investigation of a new dynode-timing technique. This method allows utilization of dynode signals from single or multiple PMTs, operated with negative high-voltage. The technique will provide an event-timing trigger without deteriorating the anode signal. A printed circuit board has been developed and built for this investigation. Benchmark measurements have been performed, comparing timing of the anode signal, timing of the inverted dynode signal and timing of the newly developed LVPECL-logic based board. Timing measurements were performed with plastic as well as LSO scintillators. From the preliminary measurements we find a gain from the dynode-timing method compared to the standard timing scheme of ~ 30 ps for two Photonis XP2020Q PMTs with LSO (10 mm times 10 mm times 10 mm). The timing-resolution improves significantly in quad-PMT (Hamamatsu R9800) detectors by ~280 ps, a factor of ~2.