High Spatial Resolution MWPC Systems Using Electromagnetic Delay Line Readouts

We describe results of an investigation to develop multiwire proportional chamber systems utilizing electromagnetic delay lines for high resolution cosmic ray experiments. The delay line used is a plexiglas core type, with a delay constant of 7 nsec/mm. The interpolation properties of this readout scheme resulted in a measured spatial resolution of 75 microns (HWHM), using iron-55 X-rays and a wire spacing of 1 mm. Tracking accuracy over a 6 mm region near the center of the chamber was better than ±7 microns when fitted to a linear spatial dependence combined with a sinusoid of wire-spacing periodicity.