Project
C-ATLAS Upgrade 2021/23

Code CERN/FIS-PAR/0026/2021

Beneficiary Entity

LIP - Laboratório de Instrumentação e Física Experimental de Partículas

Project summary

The aim of this proposal is to support a strong Portuguese participation in the work towards the ATLAS [ATLAS-EXP] experiment upgrade for the High-Luminosity LHC phase (HL-LHC) [HL-LHC]. The work plan proposed in this project focuses on specific contributions to the ATLAS Phase II upgrade, to allow ATLAS to operate at luminosities up to 7.5 times above the LHC design. These activities are already well under way, initiated during a previous funded project, and our work has had an important impact in ATLAS. The requested funding will be crucial to fulfil our scientific goals as well as the Portuguese commitments to the experiment. The ATLAS Collaboration is currently finishing Phase I of the detector upgrade [ATLAS-UPG1]. Our contributions to Phase I have been successfully completed, and included the use of the TileCal outer cells in the muon trigger, to significantly reduce the muon reconstruction fake rate in poorly instrumented rapidity regions. A new physics run (Run 3) is due to start in 2022 and last for 3 years, already at 2.5 times the design LHC instantaneous luminosity. Funding for the operation and physics exploitation activities during Run 3 is requested in a different proposal. LIP is a founding member of the ATLAS Collaboration and has made crucial contributions to the TileCal calorimeter, the forward detectors and trigger/data acquisition (TDAQ) design, construction and commissioning. Our team members have/are occupying a number of roles of responsibility in the collaboration in areas where the group is involved, and the importance of our activities was recognized by the collaboration in awarding prizes for outstanding contributions to several group members. We continue to make leading contributions to the ATLAS TileCal and TDAQ. The respective Memoranda of Understanding (MoUs) for Phase II have been signed by the Minister of Science, and represent a very significant financial contribution by the Portuguese funding agency, FCT. This contribution, however, covers exclusively the construction costs of the final deliverables. It must be matched by the necessary funding to support the associated R&D and software development effort, including the required human resources, that will ensure the proper development, design, prototyping, and debugging of thenew systems and upgrades. The most important projects that we aim to continue from the previous funded project include the complete renewal of the TileCal hadronic calorimeter High Voltage distribution system (TileCal HV) [TILEUPG2], which is entirely under LIP’s responsibility, as well as fast event reconstruction in the TDAQ using graphical processors (GPUs) as hardware accelerators. Our detailed study of the ageing of TileCal optical components proved to be crucial to realize a potential problem with loss of scintillating light yield. This has impacted on the ATLAS strategy for TileCal PMT replacement but must be continued in thecurrent project. A new area of activity will be the R&D and construction of the new High Granularity Timing Detector (HGTD) [HGTD-TDR]. This is an important new addition to ATLAS, intended to mitigate the effects of a very high pileup rate. Its inclusion in the current work programme follows from a decision by the collaboration to abandon the Hardware Tracking for the Trigger (HTT) co-processor. The HTT was one of the new systems planned for the ATLAS upgrade, and one of the areas in which we have contributed in the last few years. It was abandoned after much debate and detailed studies, in favour of a software-only approach, made possible by very significant software improvements and tuning. The current proposal has long-term strategic value, both to the ATLAS team and to LIP as a whole. Part of this value comes from supporting our long-term involvement in the TileCal. Another part comes from exploring the application of commodity computing hardware accelerators, such as GPUs, to time-critical trigger software, which we believe will pay strong dividends. And finally, the creation or consolidation, at LIP, of capabilities to produce electronics and firmware for particle physics applications, is again of strategic importance for the future. Part of this work will therefore be carried out in close collaboration withthe LIP electronics laboratory, eCRLab, and Detector Laboratory. Complementing these hardware oriented activities, other crucial tasks in this project will focus on detailed studies of the radiation-induced ageing of TileCal fibres and scintillators, exploiting our core expertise, and on specific prospective physics analyses to make the most of the HL-LHC dataset. In summary, this project has four main lines of development: development of the new TileCal HV system, performance aspects of the TileCal (optics and use in muon trigger); the challenging new HGTD detector; and the ATLAS trigger, with open ended R&D on the application of GPUs to trigger processing; and prospective physics studies.

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Support under

Reforçar a investigação, o desenvolvimento tecnológico e a inovação

Region of Intervention

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Funding

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Acknowledgements