Characterization of two prototypes for a new large area four anode photomultiplier

Two prototypes of a new large area four-anode photomultiplier have been produced by Hamamatsu for the NEMO collaboration. The new multianode photomultiplier allows us to introduce information on the direction of the detected light, by working as four individual photomultipliers. Using a testing facility realized in our laboratory, we have measured the performance of prototypes at room temperature, atmospheric pressure and under different light conditions. The response of the phototube has been measured for each anode separately. The prototype performance meets the design specifications, so these photomultipliers may be proposed for the first time for the construction of a km3 scale neutrino underwater telescope, under the KM3NeT framework.