PMT characterization for the MAGIC-II telescope

MAGIC-I, a 17 m diameter Cherenkov telescope located on the Canary Island of La Palma, is the largest single-dishsingle-dish Imaging Atmospheric Cherenkov Telescope (IACT) in the world. For lowering the energy threshold and improving the sensitivity, the MAGIC collaboration is currently building a second telescope (MAGIC-II), using photomultipliers (PMTs) with a higher sensitivity. Various measurements of different characteristics of PMTs such as single photoelectron spectrum (SPE), afterpulse, timing characteristics, aging and photoelectron detection were performed. The results from selected PMT candidates of different companies will be reported here.