Abstract
The LHCb experiment will make precision measurements of CP violation and rare b-hadron decays. Efficient particle identification with high purity over a wide momentum range is vital to these aims. The experiment employs two ring-imaging Cherenkov (RICH) detectors with three radiators, silica aerogel, C 4F 10 and CF 4, to cover the momentum range from around 1–100 GeV/ c. The RICH system employs a number of innovative techniques, both in hardware and software. A total of 484 custom-built pixel Hybrid Photon Detectors (HPDs) will be used to measure the spatial positions of Cherenkov photons with wavelengths in the range 200–600 nm, covering an active area of around 3.3 m 2. The production of the HPDs has now been completed and the tube quality, including the photo-cathode quantum efficiency, far exceeds expectations. The installation of RICH 1 is almost complete; RICH 2 has been installed and aligned, and commissioning is almost complete. Reconstruction studies incorporating realistic backgrounds indicate excellent kaon efficiencies of around 97% and pion misidentification probabilities of around 6%, averaged over the full momentum range. This paper provides a general overview of the status of the LHCb RICH project, with emphasis on the readiness for LHC start-up and for physics.
Highlights
The LHCb experiment [1] will make precision measurements of CP violation and rare decays of b hadrons at the Large Hadron Collider (LHC)
The beam-pipe directly seals to the 2 mm ring-imaging Cherenkov (RICH) 1 entrance window, which serves as the Al exit window to the LHCb vertex locator (VELO)
7.2 m to a precision of ∼150 μrad before the move; afterwards the mirror movement was estimated to be ∼100 μrad. This is to be compared with the expected RICH 2 Cherenkov angle resolution of ∼700 μrad, there was no need to re-align the mirrors in situ
Summary
The LHCb experiment [1] will make precision measurements of CP violation and rare decays of b hadrons at the Large Hadron Collider (LHC). The LHCb detector, shown, is a forward spectrometer. This design is optimized to accept the decay products of band b hadrons, which are preferentially produced with a strong angular correlation in the forward-backward directions. Two ring-imaging Cherenkov (RICH) detectors perform π/K separation from around 1 to ∼100 GeV/c. The polar angular acceptance of the upstream RICH 1 detector, in the spectrometer bending plane, is 25 to 300 mrad, while that for the downstream RICH 2 is 15 to 120 mrad. Pixel Hybrid Photon Detectors (HPDs) have been developed to detect and reconstruct the Cherenkov rings [3]. A total of 484 HPDs cover the ∼3.3 m2 total photon detection area, consisting of 196 HPDs in RICH 1 and 288 in RICH 2
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
