for the HERA-B RICH group
The performance of the ring imaging Cherenkov counter of the
HERA-B experiment is evaluated. The measured values of the basic parameters such as the number of detected photons per ring and Cherenkov
angle resolution are found to agree with a priori estimates. The counter turns out to be very robust at elevated track densities, and has been
performing stably over two years of operation, with a very low fraction of noisy channels.