MICROMEGAS: results and prospects

A lot of effort has been invested in the development of the Microstrip Gas Chamber (MSGC) [2] in order to be used as tracker for the LHC project. This technique allows good localization accuracy and double track resolution. However, it is necessary to operate it with a relatively low gas gain because of the presence of the insulator near the amplification region and because of the fragility of the structure. Recently a new preamplification structure, called GEM [3], has been introduced which can give an additional gas gain, and compensates the lack of gain of the original MSGC. Other concepts of novel proportional counters have been proposed recently: CAT [4], MICRO-DOT [5]. A review of recently developed gaseous detectors can be found in reference [6]. MICROMEGAS [1] is a high gain gaseous detector, which can stand up alone without a need of an additional preamplification. It combines high accuracy, high rate capability, excellent timing properties and robustness. These results were confirmed by a similar structure having wider amplification gap and thicker metallic grid [7].