The RICH detector of the NA62 experiment at CERN

A long focus RICH counter has been proposed as the key element for particle identification in the NA62 experiment at CERN. The purpose of this detector is threefold: to identify and reduce muons contaminating pion samples at the level or less then than 1%; to measure the arrival time of charged tracks with a precision better than 100 ps; to provide a fast signal for the level-zero trigger. The design parameters of the detector and the results of test beams performed at CERN with a prototype are described in this paper.