Spatial resolution improvement of PICOSEC Micromegas precise timing detectors

TL;DR

This paper investigates enhancing the spatial resolution of PICOSEC Micromegas detectors through high readout granularity, achieving around 0.5mm resolution with moderate timing performance, suitable for combined timing and tracking applications.

Contribution

The study demonstrates that increasing readout granularity improves spatial resolution up to a point, with detailed analysis of pad size effects on timing and spatial performance.

Findings

Achieved approximately 0.5mm spatial resolution with 3.5mm pads.

Further reducing pad size to 2.2mm did not significantly improve spatial resolution.

Timing resolution remained better than 20ps with medium granularity.

Abstract

The combination of a Cherenkov radiator with a semi-transparent photocathode and a Micromegas based amplification stage allows PICOSEC Micromegas detectors to achieve a time resolution of better than 15ps. While tileable prototypes with 10x10 channels feature 1x1 cm^2 readout pads, finer readout granularity can be used to improve the spatial resolution. We report on the study of high readout granularity PICOSEC Micromegas prototypes which achieve around 0.5mm spatial resolution with 3.5mm large pads. No significant improvement was found when readout pad size was further reduced to 2.2mm. The timing resolution of the leading pad was found to be slightly degraded but remained better than 20ps for a medium granularity prototype. The achieved spatial resolution can enable PICOSEC Micromegas to be used as precise timing and moderate resolution tracking detector simultaneously.