CERN Accelerating science

ATLAS Note
Report number	ATL-DAQ-PROC-2025-022
Title	The upgrade of the ATLAS Trigger and Data Acquisition system for the High Luminosity LHC
Author(s)	Wengler, Thorsten (CERN)
Corporate Author(s)	The ATLAS collaboration
Collaboration	ATLAS Collaboration
Publication	2025
Imprint	04 Nov 2025
Number of pages	5
In:	The 32nd International Symposium on Lepton Photon Interactions at High Energies (Lepton Photon 2025), Madison, Wisconsin, Us, 25 - 29 Aug 2025
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	TDAQ upgrade ; HL-LHC ; Run-4
Abstract	The ATLAS experiment at CERN is currently carrying out a major upgrade programme for the High-Luminosity LHC era, to be installed following the end of the current Run-3 in 2026. In order to deliver an order of magnitude more data than previous LHC runs, 14 TeV protons will collide with an instantaneous luminosity of up to $7.5 \times 10^{34}\,\mathrm{cm}^{-2}\mathrm{s}^{-1}$, resulting in much higher pileup and data rates than the current experiment was designed to handle. While this is essential to realise the physics programme, it presents a huge challenge for the detector, trigger, data acquisition and computing. The detector upgrades themselves also present new requirements and opportunities for the trigger and data acquisition system. We will discuss the motivation for the upgrade, the architecture of the trigger and data acquisition system for Run-4, and recent progress on the design, technology and construction of the system.
Copyright/License	preprint: © 2025-2026 CERN (License: CC-BY-4.0)