LHCb Silicon Tracker DAQ and ECS Online Systems

The LHCb experiment at CERN is designed to perform precision measurements of b quark decays. The Silicon Tracker plays a crucial role in reconstructing particle trajectories and consists of two silicon micro-strip detectors, the Tracker Turicensis and the Inner Tracker. The radiation environment and the magnetic field represent new challenges for the implementation of the Experiment Control System (ECS) and the data acquisition (DAQ). The DAQ has to deal with $\sim $272 000 analog read-out channels and real-time DAQ at a rate of $\sim {\hbox {1.1}}~{\hbox {MHz}}$ with data processing at the Trigger Electronics and L1 (TELL1) board level. The TELL1 real-time algorithms for clustering thresholds and other computations run on dedicated FPGAs. After data processing the total throughput amounts to about 6.4 GB from an input data rate of $\sim {\hbox {337}}~{\hbox {GB~ per ~second}}$. The ECS is based on the hierarchical finite state machine paradigm and allows distributed control access and multi-platform use. The ECS is able to control and monitor the detector hardware infrastructure (power supplies, DAQ electronics …) as well as monitor the environmental parameters. It can also take automated actions on warnings or alarms. Finally a completely independent, hardware based safety system ensures the detector safe operation.