The HADES and CBM experiment both employ gaseous RICH detectors for high performance electron identification. Currently, the HADES RICH detector is undergoing an upgrade of its photodetector in order to improve the performance for future measurements at SIS 18 and SIS 100 at GSI/ FAIR. Both RICH detectors will share the same H12700 MAPMTs from Hamamatsu and will use the same FPGA based readout electronics. Before mass production the readout electronics has been finally qualified in a proton testbeam at the COSY accelerator in November 2017. The time precision of the combined system of MAPMT and readout electronics has been measured to 260 ps, dominated by the precision of the MAPMTs. In order to enhance the UV sensitivity of the MAPMTs, WLS coatings with p-terphenyl have been investigated in detail, so far focusing on the increase of the quantum efficiency for wavelength > 200 nm. With the new fast readout electronics the decay constant of p-terphenyl was now determined to 2.4 ns comparing results from MAPMTs with and without WLS coating. These results compare well with time-resolved fluorescence measurements. This poster will present results from the COSY testbeam analysis focusing on the time precision and comparing results with and without WLS coating.
*supported by BMBF grants 05P15PXFCA, 05P15RGFCA, HGS-HiRe and GSI