Time over threshold electronics for an underwater neutrino telescope

The use of time over threshold (ToT) digitization techniques for the treatment of the output signals of the photomultiplier tubes (PMTs) of the KM3NeT detector is under consideration by the KM3NeT consortium. In this technique the leading and trailing edge of the signal above a certain threshold are time stamped and the corresponding times are sent to the onshore acquisition system. More information can be obtained by applying the same scheme at multiple threshold levels. In this note, we present the efficiency of such a digitization technique applied to signals provided by the HEllenic LYceum Cosmic Observatories Network (HELYCON) extensive air shower detector. We describe the operation and performance of these electronics and we evaluate the reconstruction accuracy of PMT signals using data collected from Extensive Air Showers of Cosmic Rays. Finally, we report on our plans to use this electronics in Optical Modules proposed for KM3NeT.