LHCb silicon tracker DAQ and DCS online systems

The LHCb experiment at the Large Hadron Collider (LHC) at CERN in Geneva (Switzerland) is designed to perform precision measurements of b quark decays. The Silicon Tracker (ST) plays a crucial role in reconstructing particle trajectories and consists of two silicon micro-strip detectors, the Tracker Turicensis upstream of the LHCb magnet and the Inner Tracker downstream. The radiation environment and the magnetic field represent new challenges for the implementation of a Detector Control System (DCS) and the data acquisition (DAQ). The DAQ has to deal with ∼272K analog read-out channels, 2K read-out chips and real time DAQ at a rate of 1.1 MHz with data processing at TELL1 level. The TELL1 real time algorithms for clustering thresholds and other computations run on dedicated FPGAs that implement 13K configurable parameters per board, in total 1.17M parameters for the ST. After data processing the total throughput amounts to about 6.4 GB from an input data rate of ∼337 GB per second. A finite state machine based hierarchical control system is the fundamental of the DCS and allows distributed control access and multi-platform use. The implementation of the DCS system for two sub-detectors requires a design which can be used for TT and IT which have a different hardware mapping. With the DCS an operator is able to control the power supplies, to program the read-out chips and to monitor online the state of all the hardware in the read-out chain. It features as well a monitoring of temperature and humidity readings and can take automated actions on warnings or alarms. To guarantee safe operation a completely independent, hardware-based system is used for the 'vital' alarms to ensure redundancy.