The performance of the ring imaging Cherenkov counter (RICH) for the HERA-B
experiment has been evaluated. The measured values of the basic parameters
such as the number of detected photons per ring and Cherenkov angle resolu
tion are found to agree with a priori estimates. Also at higher track densi
ties, the detector is capable of identifying individual rings. Particle ide
ntification has been achieved by determining the momentum from tracks in th
e vertex detector and main tracking system, hits in the electromagnetic cal
orimeter and track directions as measured by the RICH. (C) 2001 Elsevier Sc
ience B.V. All rights reserved.