Status and Plans for the CMS High Granularity Calorimeter Upgrade Project

TL;DR

The CMS High Granularity Calorimeter upgrade aims to replace existing detectors with a highly granular, radiation-hard calorimeter capable of precise energy, position, and timing measurements in the HL-LHC environment.

Contribution

This paper details the design, current status, and challenges of the innovative HGCAL project for the HL-LHC upgrade.

Findings

HGCAL will have approximately six million silicon sensor channels.

The calorimeter is designed for high radiation tolerance and precise timing (~50ps).

Project progress and upcoming challenges are summarized.

Abstract

The CMS Collaboration is preparing to build replacement endcap calorimeters for the HL-LHC era. The new high-granularity calorimeter (HGCAL) is, as the name implies, a highly-granular sampling calorimeter with approximately six million silicon sensor channels (approx. 1.1cm2 or 0.5cm2 cells) and about 250 thousand channels of scintillator tiles readout with on-tile silicon photomultipliers. The calorimeter is designed to operate in the harsh radiation environment at the HL-LHC, where the average number of interactions per bunch crossing is expected to exceed 140. Besides measuring energy and position of the energy deposits, the electronics is also designed to measure the time of their arrival with a precision in the order of 50ps. This paper summarises the reasoning and ideas behind the HGCAL, describes the current status of the project, and highlights some of the challenges ahead.