Application of the LIGA process for fabrication of gas avalanche devices

Abstract

Arrays of holes having steep wall sides have been successfully prepared by using a deep X-ray lithography technique, or LIGA process, on various thicknesses (50 - 1,000 mu m) polymethylmethacrylate (PMMA) plastic sheets. Electrical contact layers onto the top and bottom sides were deposited by metal evaporation in a vacuum. The completed LIGA devices were studied as an alternative design of the gas electron multiplier (GEM). The first measurements of performance were very promising: a lower limit to the avalanche gain of similar to 3,000 was obtained, and the actual gain is probably much larger. Detailed experimental results and field simulations will be described in this study. In addition, an application of a LIGA device to serve as a drift plane electrode, avoiding the angle dependency, will be discussed.