Test of a Silica Aerogel Threshold Cherenkov Counter for the TJNAF Hall A Spectrometers with 1-4 GeV/c Particles

摘要

The silica aerogel threshold Cherenkov counter for the Jefferson Lab Hall A spectrometers has been tested at CERN with a beam of positrons, pions and protons in order to characterize its efficiencies to particle detection in the 1 to 4 GeV/c momentum range. A detection efficiency to particles above the Cherenkov threshold (e(sup +) and (pi)(sup +)) greater than 95% and to particles below the threshold (p) of about 5% has been quoted in the whole momentum range explored. The detection efficiency to protons is due both to induced (delta)-rays production (3.5%), and to accidentals due to the high counting rate.