Performance of Drift-Tube Detectors at High Counting Rates for High-Luminosity LHC Upgrades

TL;DR

This study evaluates the performance of small-diameter muon drift-tube chambers under high background rates, demonstrating their suitability for high-luminosity LHC upgrades through experimental testing and electronics improvements.

Contribution

It introduces and validates small-diameter muon drift-tube chambers with enhanced rate capability for LHC upgrades, supported by experimental results.

Findings

Small-diameter tubes increase rate capability significantly.

Chambers perform well at background rates up to 14 kHz/cm².

Upgraded electronics further improve tracking efficiency.

Abstract

The performance of pressurized drift-tube detectors at very high background rates has been studied at the Gamma Irradiation Facility (GIF) at CERN and in an intense 20 MeV proton beam at the Munich Van-der-Graaf tandem accelerator for applications in large-area precision muon tracking at high-luminosity upgrades of the Large Hadron Collider (LHC). The ATLAS muon drifttube (MDT) chambers with 30 mm tube diameter have been designed to cope with and neutron background hit rates of up to 500 Hz/square cm. Background rates of up to 14 kHz/square cm are expected at LHC upgrades. The test results with standard MDT readout electronics show that the reduction of the drift-tube diameter to 15 mm, while leaving the operating parameters unchanged, vastly increases the rate capability well beyond the requirements. The development of new small-diameter muon drift-tube (sMDT) chambers for LHC upgrades is completed. Further improvements of tracking efficiency and spatial resolution at high counting rates will be achieved with upgraded readout electronics employing improved signal shaping for high counting rates.