Study of the d$E$/d$x$ resolution of a GEM Readout Chamber prototype for the upgrade of the ALICE TPC

TL;DR

This paper evaluates a GEM-based readout chamber prototype for the ALICE TPC upgrade, demonstrating that it maintains the current particle identification resolution after replacing MWPCs.

Contribution

It provides experimental validation that GEM readout chambers can replace MWPCs without loss of dE/dx resolution in the ALICE TPC.

Findings

GEM prototype's dE/dx resolution matches current MWPC performance.

Test beam results confirm suitability for ALICE TPC upgrade.

GEM chambers are viable for future high-luminosity conditions.

Abstract

The ALICE Collaboration is planning a major upgrade of its central barrel detectors to be able to cope with the increased LHC luminosity beyond 2020. For the TPC, this implies a replacement of the currently used gated MWPCs (Multi-Wire Proportional Chamber) by GEM (Gas Electron Multiplier) based readout chambers. In order to prove, that the present particle identification capabilities via measurement of the specific energy loss are retained after the upgrade, a prototype of the ALICE IROC (Inner Readout Chamber) has been evaluated in a test beam campaign at the CERN PS. The d$E$/d$x$ resolution of the prototype has been proven to be fully compatible with the current MWPCs.