Status of the HMPID CsI-RICH project for ALICE at the CERN/LHC

Abstract

Abstract--The ALICE High Momentum Particle Identification (HMPID) detector, presently under construction, consists of seven identical proximity focusing RICH counters, covering in total 11 m 2 and exploiting large area CsI photocathodes for Cherenkov light imaging. The detector design, assembly and quality checks will be presented, with particular emphasis on the CsI photocathodes production and validation procedure. Performance studies in beam tests of the produced detector modules and results on ageing of CsI photocathodes due to ions bombardment will be discussed.

Status and perspectives of gaseous photon detectors

“…RICH configuration/Cherenkov radiator PID (GeV/c) Photodetector/area (m 2 ) Trigger rate (Hz) Start of operation HADES@GSI [23] Mirror focusing/C 4 F 10 gas e þ /e À 0.1-1.5 MWPC/1.5 10 5 1999 COMPASS@CERN/SPS [24] Mirror focusing/C 4 F 10 gas π/K 3-55 MWPC/5.5 5 Â 10 4 2002 HALL-A@JLAB [25] Proximity focusing/C 6 F 14 liquid π/K 0.8-2.4 MWPC/1.2 10 5 2004 ALICE@LHC [26] Proximity focusing/C 6 F 14 liquid π/K 1.5-3K/p 2-5c MWPC/11 10 4 2009 PHENIX@RHIC [27] Proximity focusing/CF 4 gas e þ /e À 0.1-1.5 GEM/1. FEE.…”

Evolution and recent developments of the gaseous photon detectors technologies

“…RD26-type MWPC-based PDs have been [31] and still are successfully used by several experiments: NA44 [32] at CERN, HADES [33] at GSI, COMPASS [34] at CERN (5.5 m 2 active area), STAR [35] at RHIC, HALL-A [36] at JLAB, ALICE [37] at CERN (10 m 2 active area), etc. The impact of MWPCbased PDs on the physics results of the experiments is very relevant and they can be considered the classical successful gaseous PDs.…”

Advances in particle-identification concepts

“…The RICH counters of COMPASS [15], Hades [16], RICH at the JLAB-Hall A [18] and AL-ICE [17] experiments employ multiwire chambers with a solid CsI layer (figure 9), evaporated onto the cathode pads (figure 12) for photon detection. This photosensitive material requires a high purity chamber gas, usually methane, with water and oxygen content of order ppm, as well as careful handling of the photo-cathodes.…”