Abstract
| The large hadron collider beauty (LHCb) experiment is a forward spectrometer, designed to study beauty
and charm quarks physics at the large hadron collider (LHC).
To exploit of the higher luminosity that will be delivered during
Run3, the full experiment needed a substantial upgrade, from
the detector to the data acquisition (DAQ) and high level trigger
(HLT). In this article, we will focus on the new DAQ system
for the LHCb experiment that represents a substantial paradigm
shift compared to the previous one, and to similar systems used by
similar experiments in the past and present times. To overcome
the inefficiencies introduced by a local selection implemented
directly with the readout hardware, the Run3 system is designed
to perform a full software reconstruction of all the produced
events. To achieve this, both the DAQ and the HLT need to
process the ∼30 MHz full event-rate. In particular, this article
will introduce the final design of the system; it will provide a
focus on the hardware and software design of the event building
(EB) and how we integrated technologies designed for the high
performance computing (HPC) world — like InfiniBand HDR
(200 Gb/s) — into the DAQ system; we will present performance
measurements of the full EB system under different operational
conditions; and we will provide a feedback from EB operation
during the beginning of the data-taking. |