Speaker
Gabriel Vidal-Sitjes
(Imperial College, London)
Description
The LHCb experiment has been optimized for high precision studies of CP
violation and other rare decay phenomena in B-meson decays at the CERN
LHC. Particle Identification (PID) in the momentum range from a few to
∼100 GeV/c is essential. Hadrons in this momentum range are identified by
means of two Ring Imaging Cherenkov (RICH) detectors using Silica Aerogel,
C4F10 and CF4 gas radiators. The RICH detectors will use Hybrid Photon
Detectors (HPDs) to measure the position of Cherenkov photons over the
wavelength range 200-600 nm. The HPDs have an 83 mm diameter quartz
entrance window. Electrostatic focusing images the photocathode onto a
pixelated anode sensor, bump-bonded to a read-out chip that is
encapsulated in the tube vacuum. The anode has 1024 pixels providing 2.5
mm × 2.5 mm granularity at the photocathode and the addresses of hit
pixels are read out at the LHC bunch crossing rate of 40 MHz.A total of 484
HPDs cover an area of ∼2.6 m 2 with ∼70% active area coverage. In this
talk we describe the RICH detectors, the performance of the HPDs in
laboratory measurements and tests using charged particle beams, and the
calibration that the HPDs will require when operating in the LHCb detector.
The status of the LHCb RICH detector construction and commissioning will
be presented.
Author
Gabriel Vidal-Sitjes
(Imperial College, London)
