Interpolating Cathode Pad Readout in Gas Proportional Detectors for High Multiplicity Particle Tracks*

*This research was supported by the U.S. Department of Energy under Contract No. DE-AC02-76CH00016. Experiments which are planned for the Superconducting Super Collider and the Relativistic Heavy Ion Collider will involve interactions in which detectors will need to identify and localize hundreds or even thousands of particle tracks simultaneously. Most types of conventional position sensitive, proportional detectors with projective geometry are not able to unravel the individual tracks in these environments. We have been investigating several forms of sub-divided cathode readout to address this problem. We report here on geometric charge division using chevron shaped cathode pads which lie in rows underneath each anode wire. Investigations have quantified the nonlinear effects due to avalanche angular localization, and how these become negligible with proper design of the cathode pad. Differential non-linearity of ±5%, and position resolution in the region of 50 μm rms, have been achieved.