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May 8 – 12, 2023
Norfolk Waterside Marriott
US/Eastern timezone

One year of LHCb triggerless DAQ: achievements and lessons learned.

May 8, 2023, 11:00 AM
Marriott Ballroom V-VI (Norfolk Waterside Marriott)

Marriott Ballroom V-VI

Norfolk Waterside Marriott

235 East Main Street Norfolk, VA 23510
Oral Track 2 - Online Computing Track 2 - Online Computing


Pisani, Flavio (CERN)


The LHCb experiment is one of the four large experiments on the LHC at CERN. This forward spectrometer is designed to investigate differences between matter and antimatter by studying beauty and charm Physics. The detector and the entire DAQ chain have been upgraded, to profit from the higher luminosity delivered by the particle accelerator during Run3. The new DAQ system introduces a substantially different model for reading-out the detector data, which has not been used in systems of similar scale up to now. We designed a system capable of performing read-out, event-building and online reconstruction of the full event-rate produced by the LHC, without incurring the inefficiencies that a low-level hardware trigger would introduce. This design paradigm requires a DAQ system capable of ingesting an aggregated throughput of ~32 Tb/s, this poses significant technical challenges which have been solved by using both off-the-shelf solutions - like InfiniBand HDR - and customly developed FPGA-based electronics.
In this contribution, we will: provide an overview on the final system design, with a special focus on the event-building infrastructure; present quantitative measurements taken during the commissioning of the system; discuss the resiliency of the system concerning latency and fault tolerance; and provide feedback on the first year of operations of the system.

Consider for long presentation Yes

Primary authors

Presentation materials