7–11 Jul 2025
University of the Witwatersrand, Johannesburg
Africa/Johannesburg timezone

Overview of the current status of the High Granularity Timing Detector for the ATLAS phase 2 upgrade

8 Jul 2025, 14:40
20m
Solomon Mahlangu House (University of the Witwatersrand, Johannesburg)

Solomon Mahlangu House

University of the Witwatersrand, Johannesburg

Oral Presentation Track B - Nuclear, Particle and Radiation Physics Nuclear, Particle and Radiation Physics-2

Speaker

Rachid Mazini (School of Physics, The University of the Witwatersrand)

Description

The increase of the particle flux (pile-up) at the HL-LHC with instantaneous luminosity up to $L ≃ 7.5 × 10^{34} cm^{−2}.s^{−1}$ will have a severe impact on the ATLAS detector reconstruction and trigger performance. The end-cap and forward region where the liquid Argon calorimeter has coarser granularity and the inner tracker has poorer momentum resolution will be particularly affected. A High Granularity Timing Detector (HGTD) will be installed in front of the LAr end-cap calorimeters for pile-up mitigation and luminosity measurement. The HGTD is a novel detector introduced to augment the new all-silicon Inner Tracker in the pseudo-rapidity $\eta$ range from 2.4 to 4.0, adding the capability to measure charged-particle trajectories in time as well as space. Two silicon-sensor double-sided layers will provide precision timing information for minimum-ionising particles with a resolution as good as 30 ps per track in order to assign each particle to the correct vertex. Readout cells have a size of 1.3 mm $\times$ 1.3 mm, leading to a highly granular detector with 3.7 million channels. Low Gain Avalanche Detectors (LGAD) technology has been chosen as it provides enough gain to reach the large signal over noise ratio needed. The requirements and overall specifications of the HGTD will be presented as well as the technical design and the project status. The R&D effort carried out to study the sensors, the readout ASIC, and the other components, supported by laboratory and test beam results, will also be presented. Finally, the involvement of the ATLAS Wits/ICPP group in several HGTD activities will be discussed.

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Primary author

Rachid Mazini (School of Physics, The University of the Witwatersrand)

Co-authors

Mr Katlego Machethe (iThemba Labs) Mukesh Kumar (School of Physics and Institute for Collider Particle Physics, University of the Witwatersrand) Thabo James Lepota (School of Physics and Institute of Collider Particle Physics, University of the Witwatersrand)

Presentation materials

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