Alignment of the ATLAS Inner Detector Tracking System

TL;DR

This paper details the alignment process of the ATLAS Inner Detector tracker using cosmic ray data from 2008, demonstrating improved tracking performance and discussing implications for physics measurements.

Contribution

It presents the alignment algorithms and evaluates their effectiveness in optimizing the ATLAS Inner Detector's tracking accuracy.

Findings

Alignment algorithms successfully reduced hit residuals.

Improved consistency between upper and lower track segments.

Enhanced accuracy of track parameters for physics analyses.

Abstract

The ATLAS detector, built at one of the interaction points of the Large Hadron Collider, is operational and has been collecting data from cosmic rays. This paper describes the track based alignment of the ATLAS Inner Detector tracker which was performed using cosmic rays collected in 2008. The alignment algorithms are described and the performance of the alignment is demonstrated by showing the resulting hit residuals and comparing track parameters of upper and lower segments of tracks. The impact of the alignment on physics measurements is discussed.