Development of microstrip gas chambers on resistive supports

Summary form only. Recent developments of microstrip gas chambers (MSGCs) manufactured on various semiconducting glass and plastic supports are discussed. While in all cases short-term measurements indicate a rate capability up to and above 5*10/sup 5/ counts/s-mm/sup 2/, long-term exposure to radiation shows gain modifications, the larger the higher the resistivity of the chamber substrate, possibly due to surface charging-up. A choice of low-resistivity supports minimizes this effect. MSGCs on semiconducting glasses in the range between 10/sup 9/ to 10/sup 15/ Omega -cm and on plastic foils, (Tedlar, Kapton, ion-implanted Kapton, and Upilex) with equivalent surface resistivities between 10/sup 11/ and 10/sup 17/ Omega /square have been realized. For the more conducting supports, aging phenomena seem to appear at the highest integral fluxes, more or less pronounced depending on the gas and the materials used, in particular for the electrodes.<>