Optimization of microstrip gas chamber design and operating conditions

Abstract

the width of the cathode strips from 80 ttm to 160 ttm.anodes we predict an increase by a factor of 4 of the maximum gain when increasing gains before discharges can be obtained for wide cathodes: as an example, for 10 pm estimated the optimum geometry of the detectors. The results indicate that higher that computes fields and gains and applying the discharge criterion, we have combined field strength at the edges of the anode and cathode strips; using a programWe also discuss a model to characterize the breakdown depending on the gzgains in excess of 1 could be achieved. resolution when usig high drift fields, i.e. above 5 kV/cm; in these conditions, stable of dimethylether and carbon dioxide. Detectors exhibit lower noise and better energy were obtained using argon-dimethylether in equal percentages (50-50), and mixtures measurements we have found gas mixtures allowing high stable gains; the best results structure and operating conditions of micro-strip gas chambers. In a systematic set of We discuss recent experimental and theoretical work aimed at optimizing the ABSTRACT CERN,

“Diamond” over-coated microstrip gas chambers for high rate operation

“…Large ion current towards the drift electrode at high drift fields is typical for MSGCs. The charge gain of the MSGC is also sensitive to the strength of drift field for given voltage on the cathodes [10]. Result presented in figure 6 shows that at drift fields above 400 V/mm the charge gain increases.…”

Multiwire Gas Proportional Counters: Decrepit Antiques or ClassicPerformers?

“…Unfortunately, substrate effects have led to considerable difficulties with operational stability, particularly at high flux levels . Various studies to determine the optimum configuration for an MSGC have been performed (Bouclier, Garabatos, Manzin, Sauli, Shekhtman & Temmel, 1993;Beckers, Bouclier, Garabatos, Million, Sauli & Shekhtman, 1994 1993; Allunni, Bouclier, Fara, Garabatos, Manzin, Million, Ropelewski, Sauli, Shekhtman, Daubie, Pingot, Pestov, Busso & Costa, 1993;Budtz-Jorgensen, Bahnsen, Olesen, Madsen, Jonasson, Schnopper & Oed, 1991), but at the time of writing the optimum characteristics for an MSGC are still unclear with somewhat conflicting results being reported by different groups. It seems clear that the substrate must possess sufficient conductivity to prevent charge up and polarization, or gain instabilities will result; however, highconductivity substrates can allow high current flow which causes heating.…”

High rate behavior and discharge limits in micro-pattern detectors

“…The presence of a high field on cathode edges limits the maximum voltage that can be reached in MSGCs, even in absence of radiation, due to spontaneous field emission [13]. It has been observed that under high irradiation rate and/or exposure to heavily ionizing tracks, occasional transitions from proportional avalanche to streamer occur at high operating voltage, most of the times followed by a discharge, harmful and often fatal to the delicate structures and readout electronics.…”