ATLAS Level-1 Endcap Muon Trigger for Run 3

High Energy Accelerator Research Organization

^* e-mail: atsushi.mizukami@cern.ch

Published online: 16 November 2020

Abstract

The Large Hadron Collider is expected to operate with a centre-ofmass energy of 14 TeV and an instantaneous luminosity of 2.0 10³⁴ cm⁻²s⁻¹ for Run 3 scheduled from 2021 to 2024. In order to cope with the high event rate, an upgrade of the ATLAS trigger system is required. The level-1 endcap muon trigger system identifies muons with high transverse momentum by combining data from fast muon trigger detectors, called Thin Gap Chambers on the Big Wheel. Inner muon detectors (the Small Wheel and the Tile Calorimeter) coincidence was introduced to reduce fake muon contamination. In the ongoing Phase-1 upgrade the present Small Wheel is replaced with the New Small Wheel and additional Resistive Plate Chambers are installed in the inner region of the ATLAS muon spectrometer for the endcap muon trigger. Precision track information from the new detectors can be used as part of the muon trigger logic to enhance the performance significantly. The trigger processor board, Sector Logic, has been upgraded to handle the additional data from the new detectors. The new Sector Logic board has a modern FPGA to make use of Multi-Gigabit transceiver technology, which is used to receive data from the new detectors. The readout system for trigger data has also been re-designed to minimize the use of custom electronics and instead use commercial computers and network switches, by using TCP/IP for the data transfer. The new readout system uses a software-based data-handling. This paper describes the development of the level-1 endcap muon trigger and its readout system for Run 3.