The experimental characterisation of gas microstrip detectors. Pt. 1

Since its introduction by Oed, the gas microstrip detector (GMSD) has been studied by several groups for potential applications in high energy physics, space science, materials science and medicine. The GMSD is a form of the gas proportional counter in which an extremely precise pattern of metallisation is laid down on an insulating substrate using standard microlithographic techniques. The undoubted potential of the GMSD was vitiated throughout its early development by the presence of gain instabilities which are severely aggravated by high counting rates so robbing it of its one great advantage over a wire counter. This gain instability was quickly determined to be a result of the effect of the very high electric fields at the edge of the anode on the substrate material. In extensive tests with conventional glasses (pyrex, etc) the well-known ionic polarisation effects of such materials were shown to be responsible. The following results are taken mainly on devices fabricated on semiconducting glass. (author)