Operation and performance of the ATLAS semiconductor tracker in LHC Run 2

TL;DR

This paper reports on the operation, stability, and radiation damage studies of the ATLAS semiconductor tracker during LHC Run 2, demonstrating high efficiency despite challenging conditions.

Contribution

It provides a comprehensive analysis of the SCT's performance, stability, and radiation effects during Run 2, highlighting operational success under high luminosity conditions.

Findings

99.9% operational availability during Run 2

Data-quality efficiency of 99.85%

Detailed radiation damage studies and module degradation analysis

Abstract

The semiconductor tracker (SCT) is one of the tracking systems for charged particles in the ATLAS detector. It consists of 4088 silicon strip sensor modules. During Run 2 (2015$-$2018) the Large Hadron Collider delivered an integrated luminosity of 156 fb$^{-1}$ to the ATLAS experiment at a centre-of-mass $pp$ collision energy of 13 TeV. The instantaneous luminosity and pile-up conditions were far in excess of those assumed in the original design of the SCT detector. Due to improvements to the data acquisition system, the SCT operated stably throughout Run 2. It was available for 99.9% of the integrated luminosity and achieved a data-quality efficiency of 99.85%. Detailed studies have been made of the leakage current in SCT modules and the evolution of the full depletion voltage, which are used to study the impact of radiation damage to the modules.