Performance of New High-Precision Muon Tracking Detectors for the ATLAS Experiment

TL;DR

This paper reports on the development and deployment of small-diameter Muon Drift Tube chambers for the ATLAS experiment, significantly enhancing muon detection rate capability and spatial acceptance in high-background regions.

Contribution

Introduction of sMDT chambers with half the diameter of existing MDTs, enabling higher rate capability and better spatial coverage in the ATLAS muon spectrometer.

Findings

Twelve sMDT chambers constructed for ATLAS detector upgrade.

Chambers installed in the winter shutdown 2016/17.

Enhanced muon momentum resolution in upgraded regions.

Abstract

The goals of the ongoing and planned ATLAS muon detector upgrades are to increase the acceptance for precision muon momentum measurement and triggering and to improve the rate capability of the muon chambers in the high-background regions corresponding to the increasing LHC luminosity. Smalldiameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half the drift-tube diameter of the current ATLAS Muon Drift Tube (MDT) chambers with 30 mm drift tube diameter and otherwise unchanged operating parameters, the sMDT chambers share all the advantages of the MDTs, but have an about an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The construction of twelve chambers for the feet regions of the ATLAS detector has been completed for the installation in the winter shutdown 2016/17 of the Large Hadron Collider. The purpose of this upgrade of the ATLAS muon spectrometer is to increase the acceptance for three-point muon track measurement which substantially improves the muon momentum resolution in the regions concerned.