A new approach to study the performance characteristics of the HERA-B RICH
using momenta reconstructed with RICH track direction measurements is prese
nted. The particle identification performance is found to meet design speci
fications: electron-pion separation for momenta up to 15 GeV/c, pion-kaon s
eparation to 54 GeV/c. The normalized photo-electron yield is found to he 4
2 +/- 5 cm(-1) rad(-2) and the single-photon angular resolution is better t
han 0.7 mrad. (C) 2001 Elsevier Science B.V. All rights reserved.