A study on large area Hamamatsu photomultipliers for Cherenkov neutrino detectors

Many of the existing neutrino telescopes use large area photomultipliers integrated into transparent glass vessels to make the detection element called "optical module". The characteristics of the photomultipliers have a severe impact on the performance of the whole detectors. This paper describes a large work of characterization of large area photomultipliers performed in the frame of R&D activities of large volume underwater neutrino detectors. Dedicated studies are also reported about noise pulses, super bialkali photocathode photomultipliers, ageing effects, influences of the Earth's magnetic field and on the effects of the external glass vessels on the optical module's noise pulses.