The ALICE HMPID detector ready for collisions at the LHC

ALICE has been specifically optimized to study heavy-ion collisions at the LHC, up to a charged particle density of 8000 per unit of rapidity in central heavy-ion collisions at s NN = 5.5 TeV . The High Momentum Particle Identification Detector (HMPID) has a proximity focusing geometry with a liquid C6F14 Cherenkov radiator coupled to Multi-Wire Pad Chambers (MWPC) equipped with CsI photocathodes, over a total active area of 11 m 2 . It has been designed to identify charged pions and kaons in the range 1 ⩽ p ⩽ 3 Gev / c and protons in the range 2 ⩽ p ⩽ 5 Gev / c . The as-built detector and all relevant subsystems (gas, liquid C6F14, cooling and control) are described. Installation issues and first commissioning results are also presented.