The First Year of the HEM-B RICH

Y~ , 'P -~upL2~~~~, l-LL ?m The operational expcrience of the RICH detector Tor the first year at HERA-B is descrihcd. The design criteria, detcc- tor coinponcnts, and reconstruction software are reviewed. The results show that the main dcsign goals have been achieved. is a fine-grained forward spec- most of the timc according to the standard b trOmcter constructed around the beam-pipe to meaSl,re the fi- resulting in a kaon. Thc charge of the kaon in the decay of (he nal states of interest. Thc geometric acceptance of the detector covers about 90% of the solid angle in the CMS frame. A schcmatic of the detector is shown in Figure 1. The protons, entering from the right, interact with 8 wire targets positioned inside the heam-pipe. The particles produced in an interaction are first tracked by 8 layers of silicon strip detector, deployed within 1 cm of the beam during data-taking, with high spatial A D~~~~~ criteria