PID Session at CM XXXVIII.

Roland Hohler, GSI, presented the status of the GSI and CERN beam times. He showed the used setup configurations, simulated expectations and for the GSI experiment first data, Cherenkovrings. The expected Cherenkov angle resolution of 8.7 mrad has to be compared to the measured one of 10.2mrad. He showed also pictures from the CERN setup. Alexander Britting, Erlangen, presented measurements of the work function of photo cathode material. The MCP-PMTs from BINP show a clear shift of the workfunction of several eV after illumination. He showed the results of the Hamamatsu-L4 detector which got damaged (u-leak) at the CERN beam time. Lifetime measurements of the Hamamatsu-M16 show no damage of the photo cathode after an illumination of 80mC/cm2. Oliver Merle, Giessen, improved the simulated Cherenkov ring reconstruction by including a dark noise model and a dead time model. Reconstruction works well until a dark count rate of 90 HZ per SiPm pixel. He achieves less than 1% misID at 4.5GeV/c and 22degree. Their next hardware prototype will be a disk quarter of borofloat 33 glass with a roughness of Rq=3nm read out by H10515B-100 detectors. Carsten Schwarz, GSI, discussed the procedure to enter the DIRC author list for papers representing the PANDA DIRCs. There is a formulated procedure for becoming an active member of the DIRC group and entering the autor list, and a procedure to leave the author list. Since interested groups, attending the DIRC meetings, have not yet funding and are not able to contribute sufficiently, these procedures cannot yet be applied strictly. For the moment they are applied for active groups and not applied for passive groups, who are expected to contribute in the near future. Valery Dodokhov, Dubna, showed the status of the radiator polishng at LZOS in Lytkarino. The four 900mm bars are polished and the roughness of specimens are measured with atomic force microscopes. The roughness is between 0.5-1.5nm. The damaged area at the edges for the 4 radiators ranges from 0.24 to 12.13mm2.