Study in a beam test of the resolution of a Micromegas TPC with standard readout pads

TL;DR

This paper reports on a beam test of a Micromegas TPC, measuring its resolution and drift properties under magnetic fields, and compares results with simulations and analytical models, highlighting fundamental limitations.

Contribution

It provides new experimental data on Micromegas TPC resolution and drift properties, validated against simulations, for potential application in Linear Collider TPCs.

Findings

Measured drift properties of argon-isobutane mixture

Point resolution close to fundamental limits

Performance suitable for Linear Collider TPCs

Abstract

The results of a beam test performed at the KEK PS in June 2005 are presented. Drift properties of an argon-isobutane mixture have been accurately measured and compared with predictions at magnetic fields between 0 and 1 Tesla. The r.m.s. point resolution of a padrow is compared with simulation and with an analytical calculation. The fundamental limitations due to detector geometry and gas properties are reviewed and the measured performances of the detector are found to be close to this limit. A numerical application to the case of a Linear Collider TPC is presented.