LHCb RICH 2 Engineering Design Review Report Nota Interna Pubblica LHCb Collaboration CERN LHCb EDR 2002-009 1March 2002

The LHCb detector is a single arm spectrometer designed to exploit the large number of\nb-hadrons produced at the LHC in order to make precision studies of CPa symmetries and\nof rare decays in the B-meson system. It is therefore essential for the experiment that the\ndetector configuration includes a particle identification system with high separation power\nbetween kaons and pions. We will present in this note the engineering solutions for the\nlightweight, high precision Ring Imaging Cherenkov detector, RICH 2, of the spectrometer.\nThe design is built around a large space frame used as a high stability support for the\noptical system and as a supporting structure for the magnetic shielding needed for the photon\ndetectors. All material not essential for the operation of the detector is located outside the\nacceptance of the spectrometer. The space frame also defines the Cherenkov gas volume.