Position sensing from charge dispersion in micro-pattern gas detectors with a resistive anode

Micro-pattern gas detectors, such as the Gas Electron Multiplier (GEM) and the Micromegas need narrow high-density anode readout elements to achieve good spatial resolution. A high-density anode readout would require an unmanageable number of electronics channels for certain potential micro-detector applications such as the Time Projection Chamber. We describe below a new technique to achieve good spatial resolution without increasing the electronics channel count in a modified micro-detector outfitted with a high surface resistivity anode readout structure. The concept and preliminary measurements of spatial resolution from charge dispersion in a modified GEM detector with a resistive anode are described below.