Aerogel as Cerenkov radiator for RICH detectors
April 4, 2002
Aerogel as Cerenkov radiator is used already in low intensity, low moltiplicity environment (e.g. HERMES experiment).
The LHCb detector plans to use it, with n=1.03, in the hot environment of pp collisions at 14 TeV at LHC. The purpose is to cover the 'k-tagging' region and the large multiplicity decays of the B particle, corresponding to a range of about 2 - 10 GeV.
It is necessary to have exceptional quality of aerogel, in order to obtain the best photoelectron yield and the best angular resolution.
Two qualities of aerogel are tested. Results on Np.e.,
σθ and π-p separation from a test beam with particle momenta in the range 6-10 GeV are given. The photodetectors used were 4 large HPDs, designed and built at CERN. They have a 5" diameter and the anode is divided in 2048 pads.
A comparison data-MonteCarlo expectations is performed.
Ageing tests under intense radiations (γ,p,n) have also been carried out.