Simulating the Charge Dispersion Phenomena in Micro Pattern Gas Detectors with a Resistive Anode

摘要

The TPC for the International Linear Collider (ILC) will need to measureabout 200 track points with a transverse resolution close to 100 microns. Theresolution goal is beyond the capability of the conventional proportionalwire/cathode pad TPC and Micro-Pattern Gas Detectors (MPGD) are being developedto meet the challenge. The standard MPGD readout techniques will, however, havedifficulty in achieving the ILC-TPC resolution goal with the 2 mm x 6 mm padsas was initially envisioned. Proposals for smaller width pads will improve theresolution but will require a larger number of readout channels and increasethe TPC detector cost and complexity. The new MPGD readout concept of chargedispersion has the potential to achieve the ILC-TPC resolution goal withoutresorting to narrower pads. This was recently demonstrated in cosmic ray testsof a small prototype TPC read out with MPGDs using the charge dispersiontechnique. Here we describe the simulation of the charge dispersion phenomenafor the MPGD-TPC. The detailed simulation includes initial ionizationclustering, electron drift, diffusion effects, the intrinsic detectorpulse-shape and electronics effects. The simulation is in excellent agreementwith the experimental data and can be used to optimize the MPGD chargedispersion readout for the TPC.