Simulation of electrostatic properties and gas amplification in microstrip gas chambers and comparison with measurements

Abstract

had raised by about 30 %, when the high voltage was on during heating, but remained OCR Output orders of magnitude by heating it to 60°C for two days. After cooling down the gain verify this prediction we have reduced the resistivity of the substrate by more than two D263) used by us. However in long term applications a rising gain is expected. To So far we have not observed this effect under normal conditions with the glass (Schott this region would be accompanied by a high field and increased gas amplification [12]. the migration of the alkali ions in glasses [11] is also ignored. The high resistivity in A possible charge carrier depletion zone near the anode, which could be caused by resistivities.strength [10]. We neglect this field dependence and assume uniform bulk and surface Experimentally it is known that the conductivity in glasses increases with the field critica.lly on the treatment of the surface Glasses and plastic substrates have a non negligible surface conductivity which depends 2.1 Substrate properties tions, where the performance is deteriorating due to high rates are not simulated.For the computation of the electric field we neglect the ions in the gas. Thus condi applicability of the results.are not necessarily valid for all operating conditions of the detector and may limit the processes and preferred to use a simple model. As a consequence the computations have avoided the introduction of adjustable empirical parameters to account for theseThe processes occurring in a MSGC are far too complicated to be simulated in detail. We 2 The simulation model size of signals induced on the cathode strips and back plane electrodes.geometric parameters on the field, the gas amplification, the anode capacitance, and the surements with glass substrates. Finally in section 4 we estimate the effect of some to compute the field for different configurations and compare the simulation to meaIn the following section we describe the method, which then is used in section 3 amplification for the standard 90:10 argon methane mixture.currents. To allow comparisons with experimental data we have also simulated the gas applied the charge simulation method and included the influence of surface and bulk ref. [5] are similar to those presented here, but differ in the assumptions made for the encouraging steps in this direction have been done [5, 6,7,8]. The investigations of which could be reduced if reliable simulations with predictive power were available. VeryThe production and test of different structures is a tedious and expensive procedure the published results can be found in [2,3,4]. interesting developments since the first realization by A. Oed References to most of bers are replaced by lithographically produced strips on solid substrates have had many Gas microstrip detectors in which the wires of the standard multiwire proportional cham

Simulation of 3D electrostatic configuration in gaseous detectors

“…Three popular types of MPGDs, namely MicroStrip Gas Chamber (MSGC), microMEsh GAseous Structure (mi-croMEGAS) and MicroWire Detector (MWD) have been dealt with in order to simulate their electrostatic configurations. The accuracy of the results has been confirmed by comparing them with existing 2D BEM for MSGC [11] and with 3D FEM results for microMEGAS and MWD [12].…”

“…The potential contours on central XY -plane as calculated by neBEM with a vacuum substrate (dielectric constant 1.0) is presented in figure 3. A comparative study of electric field has been made between the present results and 2D calculation following charge simulation method [11]. In the geometry, two different substrates, namely vacuum and glass (dielectric constant 5.0), have been considered each with two different thickness, 100µm and 500µm.…”

“…In the geometry, two different substrates, namely vacuum and glass (dielectric constant 5.0), have been considered each with two different thickness, 100µm and 500µm. The cross-sections used in the neBEM calculation have been made identical to that used in 2D calculation in [11]. The drift plane is placed 1cm away from anodecathode plane and provided with a voltage of −3kV .…”