Micromegas: Large-Size High-Rate Trackers in the High Energy Experiment COMPASS

Between 2002 and 2006, the COMPASS high-rate experiment at CERN has been successful using the Micromegas technique to reach high performances in particle detection. The twelve 40 cm times 40 cm Micromegas planes, the largest gaseous micro-pattern detectors ever used to date in a high energy experiment, provide an excellent tracking device in the hottest part of the spectrometer, even with the use of hadron beams. The detectors see a total flux of 30 MHz, with rates reaching 5 kHz/mm
²
in the region close to the beam. So far, they have accumulated more than 1 mC/mm
²
in their central region without experiencing any damage.