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 ~272 K analog read-out channels, 2 K 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 13 K configurable parameters per board, in total 1.17 M 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.