The Pixel Luminosity Telescope: A detector for luminosity measurement at CMS using silicon pixel sensors

TL;DR

The Pixel Luminosity Telescope at CMS uses silicon pixel sensors to measure luminosity precisely during LHC runs, providing essential calibration data and systematic uncertainty assessments for high-energy physics experiments.

Contribution

This paper introduces the design, commissioning, and operational performance of the Pixel Luminosity Telescope at CMS, highlighting its role in luminosity measurement and calibration during LHC Run 2 and preparations for Run 3.

Findings

Successful measurement of per-bunch luminosity at 40 MHz

Effective calibration and correction procedures established

Stable operation during LHC Run 2 and readiness for Run 3

Abstract

The Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment at the LHC. It is located approximately 1.75 m from the interaction point and arranged into 16 "telescopes", with eight telescopes installed around the beam pipe at either end of the detector and each telescope composed of three individual silicon sensor planes. The per-bunch instantaneous luminosity is measured by counting events where all three planes in the telescope register a hit, using a special readout at the full LHC bunch-crossing rate of 40 MHz. The full pixel information is read out at a lower rate and can be used to determine calibrations, corrections, and systematic uncertainties for the online and offline measurements. This paper details the commissioning, operational history, and performance of the detector during Run 2 (2015-18) of the LHC, as well as preparations for Run 3, which will begin in 2022.