THE OPERATION OF PLASTIC MSGCS AT HIGH-RATES

The operation of MicroStrip Gas Counters (MSGCs) on a Upilex (polyimid e) substrate is described. The surface resistivity of the substrate wa s reduced by ion implantation or by coating with a thin film of nickel oxide. Results are presented concerning the surface resistivity and i ts stability, The lowering of the substrate resistivity allows MSGCs t o operate at very high rates and several devices were tested in a high flux X-ray beam. Substrates with optimum resistivity showed no gain c hanges whereas gain changes were seen on those with higher resistivity .