The CMS Phase-1 Pixel Detector Upgrade

TL;DR

The paper details the design, construction, and initial performance of the upgraded CMS Phase-1 pixel detector, which enhances tracking and coverage to handle higher luminosities at the LHC.

Contribution

It presents the novel design and successful implementation of the upgraded pixel detector for improved performance at higher luminosities.

Findings

Enhanced tracking performance observed in early operation

Lower mass and improved coverage compared to the original detector

Successful commissioning and initial data-taking performance

Abstract

The CMS detector at the CERN LHC features a silicon pixel detector as its innermost subdetector. The original CMS pixel detector has been replaced with an upgraded pixel system (CMS Phase-1 pixel detector) in the extended year-end technical stop of the LHC in 2016/2017. The upgraded CMS pixel detector is designed to cope with the higher instantaneous luminosities that have been achieved by the LHC after the upgrades to the accelerator during the first long shutdown in 2013-2014. Compared to the original pixel detector, the upgraded detector has a better tracking performance and lower mass with four barrel layers and three endcap disks on each side to provide hit coverage up to an absolute value of pseudorapidity of 2.5. This paper describes the design and construction of the CMS Phase-1 pixel detector as well as its performance from commissioning to early operation in collision data-taking.