The LHCb experiment is a forward spectrometer, designed to study beauty and charm quarks Physics at the 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 paper, 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 paper 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.
LHCb (Large Hadron Collider beauty) is one of the four large particle physics experiments aimed at studying differences between particles and anti-particles and very rare decays in the charm and ...beauty sector of the standard model at the LHC. The Experiment Control System (ECS) is in charge of the configuration, control, and monitoring of the various subdetectors as well as all areas of the online system, and it is built on top of hundreds of Linux virtual machines (VM) running on a Red Hat Enterprise Virtualisation cluster. For such a mission-critical project, it is essential to keep the system operational; it is not possible to run the LHCb’s Data Acquisition without the ECS, and a failure would likely mean the loss of valuable data. In the event of a disruptive fault, it is important to recover as quickly as possible in order to restore normal operations. In addition, the VM’s lifecycle management is a complex task that needs to be simplified, automated, and validated in all of its aspects, with a particular focus on deployment, provisioning, and monitoring. The paper describes the LHCb’s approach to this challenge, including the methods, solutions, technology, and architecture adopted. We also show limitations and problems encountered, and we present the results of tests performed.
The LHCb experiment has gone through a major upgrade for LHC Run 3 at CERN, scheduled to start in the middle of 2022. The entire readout system of the experiment has been replaced by Front-End and ...Back-End electronics that are able to record LHC events at the full LHC bunch crossing rate of 40 MHz. In order to maintain synchronicity across the full system, clock and control commands are originated from a single Readout Supervisor (SODIN) and distributed downstream through a Passive Optical Network (PON) infrastructure, reaching all Back-End cards of the readout system, via a two-level hierarchy and utilizing PON splitters. An FPGA firmware core, called LHCb-PON and based on the CERN TTC-PON, is instantiated on SODIN and all Back-End cards and provides the communication protocol while ensuring a stable distribution of control commands within the readout period of 25 ns as well as a clock signal with fixed and deterministic latency with a precision of a few hundreds of picoseconds. This is achieved by the firmware backbone that provides clock recovery and ensures the transmission of a control word downstream with fixed latency. Additionally, the LHCb-PON also provides monitoring functionalities over the upstream link, with less strict timing requirements, connecting multiple Back-End cards to the central SODIN. This is achieved by having each Back-End card send data upstream through a Time Division Multiplexing scheme. This paper describes the implementation, measurements and results from the usage of the system during the start-up of The LHC Run 3.
In 2017 the CERN IT department and the major LHC experiments reviewed the possibility to build a common High Level Trigger facility, to share costs and for a more efficient utilization of computing ...resources. This paper describes a Proof-of-Concept built by the CERN IT-CS group and the LHCb online and offline teams to demonstrate the feasibility of the proposal: the dedicated, high speed connection between the LHCb detector and the IT data-centre, the setup of the servers and how they were used for offline simulation and online data taking, the different technologies considered and used, the challenges encountered and how they were tackled. The Proof of Concept exceed expectations and the remote servers were used for real data taking for more than two months during the summer 2018.
LHCb is one of the 4 LHC experiments and continues to revolutionise data acquisition and analysis techniques. Already two years ago the concepts of “online” and “offline” analysis were unified: the ...calibration and alignment processes take place automatically in real time and are used in the triggering process such that Online data are immediately available offline for physics analysis (Turbo analysis), the computing capacity of the HLT farm has been used simultaneously for different workflows : synchronous first level trigger, asynchronous second level trigger, and Monte-Carlo simulation. Thanks to the same software environment, LHCb can switch seamlessly and fast from Online to Offline workflows, run them simultaneously and thus maximize the usage of the HLT farm computing resources.
LHCb is one of the 4 experiments at the LHC accelerator at CERN. During the upgrade phase of the experiment, several new electronic boards and Front End chips that perform the data acquisition for ...the experiment will be added by the different sub-detectors.
These new devices will be controlled and monitored via a system composed of GigaBit Transceiver (GBT) chips that manage the bi-directional slow control traffic to the Slow Control Adapter(s) (SCA) chips. The SCA chips provide multiple field buses to interface the new electronics devices (I2C, GPIO, etc). These devices will need to be integrated in the Experiment Control System (ECS) that drives LHCb.
A set of tools was developed that provide an easy integration of the control and monitoring of the devices in the ECS. A server (GbtServ) provides the low level communication layer with the devices via the several user buses in the GBT-SCA chip and exposes an interface for control to the experiment SCADA (WinCC OA), the fwGbt component provides the interface between the SCADA and the GbtServ and the fwHw component, a tool that allows the abstraction of the devices models into the ECS. Using the graphical User Interfaces or XML files describing the structure and registers of the devices it creates the necessary model of the hardware as a data structure in the SCADA. It allows then the control and monitoring of the defined registers using their name, without the need to know the details of the hardware behind. The fwHw tool also provides the facility of defining and applying recipes named sets of configurations which can be used to easily configure the hardware according to specific needs.
LHCb MiniDAQ control system Granado Cardoso, Luís; Gaspar, Clara; Viana Barbosa, João ...
EPJ Web of Conferences,
2019, Volume:
214
Journal Article, Conference Proceeding
Peer reviewed
Open access
LHCb is one of the 4 experiments at the LHC accelerator at CERN,
specialized in B-physics. During the next long shutdown period, the LHCb
experiment will be upgraded to a trigger-less readout system ...with a full software trigger in order to be able to record data with a much higher instantaneous luminosity. To achieve this goal, the upgraded systems for Timing and Fast Control (TFC) and Data Acquisition (DAQ) will have new electronic boards and a new software stack will be introduced for data acquisition. In the development stage, all these components are housed in servers named MiniDAQ. These new components will need to be integrated in an upgraded Experiment Control System (ECS) based on the WinCC OA SCADA and the CERN JCOP framework. The ECS provides full monitoring and control for all these subsystems and many important features like configuration recipes and automated actions. This paper describes the implementation of the upgraded ECS and its component fwMiniDAQ, which integrates all the new developments and can be easily distributed to the sub-detector developers and configured for their various setups.
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