22 Feb 2011



The LHCb RICH Detector System


​Cherenkov angle versus momentum from the LHCb RICH 1 detector showing different particle types


The LHCb Ring Imaging Cherenkov (RICH) detector system consists of two detectors (RICH 1 and RICH 2) and can identify particles (mainly hadrons) in the momentum range 2-100 GeV/c. RICH 1 performs better at low momentum (up to 50 GeV/c) while RICH 2 works best at high momentum (above 30 GeV/c). RICH 1 was originally designed for two radiators: gas and aerogel. The aerogel was removed for the LHC Run II, as the operating luminosity of LHCb is double the design luminosity and the conditions were too challenging for the aerogel. The gas radiators are C4F10 for RICH 1 and CF4 for RICH 2.

The RAL group (including colleagues in Technology Department) has:

  • Manufactured the structure of the RICH2 detector in collaboration with industry and constructed the entry and exit windows of the detector at CERN.
  • Written the detailed simulation software to model the RICH detectors in the main Monte-Carlo programme.
  • Developed laser alignment and gas monitoring systems.
  • Developed the control software for the RICH detectors.


Left: RICH 2 being installed in the LHCb experimental hall

Right: RAL TD engineers construct the carbon fibre entry window of RICH 2 at CERN