# Performance of a GridPix TPC readout based on the Timepix3 chip

## TL;DR

This paper evaluates a GridPix TPC readout with Timepix3 chips, demonstrating high efficiency, precise track measurement, and improved momentum resolution for future collider detectors.

## Contribution

It introduces a GridPix readout system with Timepix3 chips, showing its effectiveness for high-precision TPC measurements and potential for large-scale detector applications.

## Key findings

- High detection efficiency for single ionization electrons
- Energy loss resolution of 4.1% over 1 meter
- Simulation indicates 20% improvement in TPC momentum resolution

## Abstract

With the ultimate goal of developing a pixel-based readout for a TPC at the ILC, a GridPix readout system consisting of one Timepix3 chip with an integrated amplification grid was embedded in a prototype detector. The performance was studied in a testbeam with 2.5 GeV electrons at the ELSA accelerator in Bonn. The error on the track position measurement both in the drift direction and in the readout plane is dominated by diffusion. Systematic uncertainties are limited to below 10 $\mu$m. The GridPix can detect single ionization electrons with high efficiency, which allows for energy loss measurements and particle identification. From a truncated sum, an energy loss (dE/dx) resolution of 4.1% is found for an effective track length of 1 m. Using the same type of chips, a Quad module was developed that can be tiled to cover a TPC readout plane at the ILC. Simulation studies show that a pixel readout can improve the momentum resolution of a TPC at the ILC by about 20%.