Studies on different MaPMTs for a DIRC detector at the WASA-at-COSY experiment

The WASA-at-COSY experiment at the Forschungszentrum Juelich provides a nearly 4π detector including a forward spectrometer for studies on η- and η'-meson decays in proton-proton collisions. Simulations have shown that an additional Detector of Internally Reflected Cherenkov light (DIRC) in front of the Forward Range Hodoscope will significantly increase the particle identification and energy resolution for both the decayed particles and the background. The light generated inside the DIRC radiator is guided under total internal reflection towards the edge of the radiator where it is focused on a photon readout system by a special optic. For the reconstruction of the Cherenkov angle the photon readout system needs a good spatial resolution. This can be achieved by multi-anode photomultipliers (MaPMT). We report on studies of the characteristics of different MaPMTs (Hamamatsu Type H8500C, H9500 and H6568) and on results from a first test of a DIRC prototype at COSY.