DESIGN AND CHARACTERISTICS OF MICROGAP COUNTERS ON SILICON

The microgap couter (MGC) is a promising development in the field of s mall gas-filled position sensitive detectors. In the MGC the anode str ips are carried by small insulating ridges of SiO2 or polyimide, that are mounted on top of the cathode strips. The exact widths of the anod e and the insulator strips can play an important role in the maximum a ttainable gas gain. We present results of a study of the gas gain and the maximum anode-cathode potential for anode widths running from 4 to 15 mu m and SiO2 strip widths between 6 and 30 mu m. For the realisat ion of these micro-structures in standard IC technology, we use a wafe r stepper machine with a step size of 1 x 1 cm(2). Despite this surfac e limitation, we have managed to enlarge the MGC to an active area of 5 x 5 cm(2). Details about this project will be highlighted. (C) 1998 Elsevier Science B.V. All rights reserved.