Implementation of a Large Scale Control System for a High-Energy Physics Detector: The CMS Silicon Strip Tracker

Control systems for modern High-Energy Physics (HEP) detectors are large distributed software systems managing a significant data volume and implementing complex operational procedures. The control software for the LHC experiments at CERN is built on top of a commercial software used in industrial automation. However, HEP specific requirements call for extended functionalities. This thesis focuses on the design and implementation of the control system for the CMS Silicon Strip Tracker but presents some general strategies that have been applied in other contexts. Specific design solutions are developed to ensure acceptable response times and to provide the operator with an effective summary of the status of the devices. Detector safety is guaranteed by proper configuration of independent hardware systems. A software protection mechanism is used to avoid the widespread intervention of the hardware safety and to inhibit dangerous commands. A wizard approach allows non expert operators to recover error situations and minimizes the downtime due to errors. Finally, the possibility of using a model-based methodology for prototyping 3D user interfaces for control systems is investigated. The presented software is in continuous operation for the control of the CMS tracker while some general solutions have been adopted in the control systems of other CMS sub-detectors.