An aging study of semiconductive microstrip gas chambers and a gas electron multiplier

The aging behavior of wire chambers have been of great interest for many years. Recently a new generation of proportional chambers have been developed including the microstrip gas chamber (MSGC) microgap chamber (MGC) and gaseous electron multiplier (GEM). Aging studies of these detectors are of particular interest to the LHC (Large Hadron Collider) community because the baseline design of the CMS experiment includes MSGCs as part of the tracking system. In this work we report aging studies of two MSGC's and a GEM detector with a MSGC used for readout. The GEM is constructed from Kapton and copper, the MSGC's are constructed from semiconductive glass and gold. When the MSGC's are operated in argon and dimethyl ether (DME) gas mixture and irradiated with a 6 KeV photon beam, > 100 mC/cm charge can be accumulated without degradation of the detector performance while the GEM+MSGC can tolerate 220 mC/cm without degradation of performance, corresponding to about 20 years of operation at the LHC.