Author/Authors :
Abbon، نويسنده , , P. and Alekseev، نويسنده , , Holger M. and Angerer، نويسنده , , H. and Apollonio، نويسنده , , M. and Birsa، نويسنده , , C. Marisa R. and Bordalo، نويسنده , , P. and Bradamante، نويسنده , , F. and Bressan، نويسنده , , A. and Busso، نويسنده , , L. and Chiosso، نويسنده , , M. and Ciliberti، نويسنده , , P. and Colantoni، نويسنده , , M.L. DA COSTA LOUZADA1، نويسنده , , S. and Dafni، نويسنده , , T. and Dalla Torre، نويسنده , , S. and Delagnes، نويسنده ,
Abstract :
A fast photon detection system has been built for the upgrade of COMPASS RICH-1, the large size gaseous RICH detector in use at the COMPASS Experiment at the CERN SPS since 2001. The photon detectors of the central region have been replaced by a new system based on multi-anode photomultipliers coupled to individual fused silica lens telescopes and a fast readout electronics system, while in the outer region the existing MWPCs with CsI photocathodes have been equipped with a new readout system, based on the APV chip. RICH-1 has been successfully operated in its upgraded version during the 2006 run. We report on the upgrade design and construction, and on the preliminary characterization of the upgraded RICH-1 performances: at saturation about 60 photons per ring have routinely been obtained and the background level has drastically been reduced thanks to the good time resolution of the new system, leading to a 2 σ π –K separation above 55 GeV/c.
Keywords :
COMPASS , rich , Multi-anode photomultiplier tubes , UV lenses , Photon detection
