Gas electron multiplier made by deep-etch X-ray lithography

Abstract

dAs an alternative design for a gas electron multiplier (GEM), which is a charge preamplifying device when coupled with any gas avalanche microdetector, arrays of holes having steep walls have been successfully prepared on polymethylmethacrylate (PMMA) plastic sheets of various thicknesses by using a deep-etch X-ray lithography or LIGA process. The first measurements of performance were very promising. For a 300-mum-thick LlGA device, an avalanche gain of similar to3 x 10(3) was obtained from anode strips having the 10-mum width of the microstrip gas chamber (MSGC) used as a readout collection plane. The short-term stability of the gain was found to be constant, within 2% change of the gain over a one and one-half hour period, and the rate capability was extended to more than 10(5), mm(-2).s(-1).