A large area CsI RICH Detector in ALICE at LHC

A 1m<SUP>2</SUP> CsI RICH prototype has been successfully tested in a hadron beam at CERN SPS. The prototype, fully equipped with 15k electronic channels, has been used to identify particles coming from pi-Be interactions. Track reconstruction has been performed by using a telescope consisting of four gas pad chambers. A detailed description of the detector will be presented and results from the test will be discussed.<P>List of figures<UL><LI>Figure 1 <A HREF="fig_11.27_bw.eps">Expected proton and antiproton yields including jet quenching mechanism in central Pb-Pb collisions at LHC.</A><LI>Figure 2 <A HREF="richscheme.eps">Schematic view of the HMPID CsI-RICH</A><LI>Figure 3 <A HREF="fig2-30a.eps">Experimental layout used at the SPS/H4 test beam</A><LI>Figure 4 <A HREF="fig2-36a.eps">Distributions of the mean number, per ring, of pad hits (<I>N<SUB>pad</SUB></I>), electrons (<I>N<SUB>tot</SUB></I>) and Cherenkov photoelectrons (<I>N<SUB>res</SUB></I>) as a function of the single-electron mean pulse height</A><LI>Figure 5 <A HREF="fig2-52a.eps">Mean single-electron pulse height as a function of high voltage measured at the centre of each of the four photocathodes</A><LI>Figure 6 <A HREF="uniformity.eps">Evaluation of the uniformity of the chamber gain for the photocathode PC32</A><LI>Figure 7 <A HREF="fig2-51.eps">Azimuthal distribution of the photon pad hits in the Cherenkov fiducial zone (HV=2050 V)</A><LI>Figure 8 <A HREF="fig4-14.eps">Photon angle (a) and track Cherenkov angle (b) distributions for beam events at the SPS</A><LI>Figure 9 <A HREF="fig2-69.eps">Track density on the HMPID cathode plane in real 350 GeV/c pi<SUP>-</SUP>-Be events</A><LI>Figure 10 <A HREF="r2137_14_3d.eps">Three dimensional display of an SPS 350 GeV/c pi<SUP>-</SUP>-Be event. Eleven tracks are reconstructed in the telescope by requiring one hit on each pad chamber to reconstruct a track</A></UL>