A Comparative Study of Straight-Strip and Zigzag-Interleaved Anode Patterns for MPGD Readouts

TL;DR

This study compares straight-strip and zigzag-interleaved anode patterns in MPGD readouts, demonstrating that zigzags can achieve comparable or better position resolution with fewer channels by optimizing geometric parameters.

Contribution

The paper provides a systematic comparison of zigzag and straight-pad anode patterns, highlighting the advantages of zigzags in reducing channels while maintaining high spatial resolution.

Findings

Zigzag patterns achieve similar or better resolution than straight pads.

Fewer channels are needed with zigzag anodes for the same performance.

Optimized zigzag geometries provide uniform response without pad response functions.

Abstract

Due to their simplicity and versatility of design, straight strip or rectangular pad anode structures are frequently employed with micro-pattern gas detectors to reconstruct high precision space points for various tracking applications. The particle impact point is typically determined by interpolating the charge collected by several neighboring pads. However, to effectively extract the inherent positional information, the lateral spacing of the straight pads must be significantly smaller than the extent of the charge cloud. In contrast, highly interleaved anode patterns, such as zigzags, can adequately sample the charge with a pitch comparable to the size of the charge cloud or even larger. This has the considerable advantage of providing the same performance while requiring far fewer instrumented channels. Additionally, the geometric parameters defining such zigzag structures may be tuned to provide a uniform detector response without the need for so-called pad response functions, while simultaneously maintaining excellent position resolution. We have measured the position resolution of a variety of zigzag shaped anode patterns optimized for various MPGDs, including GEM, Micromegas, and micro-RWELL and compared this performance to the same detectors equipped with straight pads of varying pitch. We report on the performance results of each readout structure, evaluated under identical conditions in a test beam.