HIGH-RATE OPERATION AND LIFETIME STUDIES WITH MICRO-STRIP GAS-CHAMBERS

Micro-Strip Gas Chambers manufactured on supports with low resistivity , 10(9) to 10(12) Omega cm, can withstand without gain loss due to cha rging-up the very high rates expected in tracking detectors at CERN's Large Hadron Collider. Several technologies allowing to realize suppor ts in this range of resistivity are described, namely electron-conduct ing glass and thin-layer conductive coatings. At very high radiation f luxes, the formation and deposit on electrodes of thin insulating laye rs cause premature deterioration of the detector. The ageing rate is f ound to be extremely sensitive to the purity and nature of the filling gas, and can be kept small only by a careful selection of the manufac turing materials. Experimental results on ageing are presented for sev eral types of detectors.