A Distributed Monitoring and Control System for the Laser Ion Source RILIS at CERN-ISOLDE

In this work, the implementation of the LabVIEW-based RILIS Equipment Acquisition and Control Toolset (REACT) software framework is documented, revised, and further developed to accomplish remotely operated in-source laser spectroscopy experiments at CERN-ISOLDE. The Resonance Ionization Laser Ion Source (RILIS) is an integral part of the radioactive ion beam user facility ISOLDE at CERN. Its task as an ion source is to ensure high isobaric purity and production efficiency of the ion beams that are generated for the various experimental setups of the facility. Reliable operation requires directing 3 pulsed laser beams, precisely wavelength-tuned and overlapped in time to a precision of 5 nanoseconds, to converge into a 3mm diameter ion source cavity located 25m away in an inaccessible radioactive environment. These stable conditions have to be maintained for up to 7 days at a time per experiment setup. Within recent years, the array of RILIS equipment and its need to interface with other experimental apparatus outside of the laser laboratory has steadily grown. This has increased the demand for developing software to address machine supervision and data acquisition tasks, as well as installing automated safety systems. In order to meet these demands, a distributed monitoring and control system was commissioned and continually developed since 2011, which focuses on modularity and flexibility to adapt to changing experiment requirements. The system is implemented using the data-flow oriented graphical programming language LabVIEW and makes extensive use of the integrated shared variable technology to facilitate network data communication. The presented work documents the conceptual design, implementation details and newly developed functionalities for programs currently available to the RILIS operators to support the setup and operation of the laser ion source equipment. Moving the supervisory control of the RILIS installation to a separate building outside the designated radiation supervised ISOLDE hall area has compounded the need for commissioning a new control room and implementing comprehensive remote monitoring, control, and automation programs for the crucial laser parameters. In the course of this thesis work, this entailed the development of stabilization programs for the laser power, laser timing, and the laser wavelength. Additional software components have been refactored and extended to make use of the modular and extensible structure of the equipment communication programs within the REACT framework. These developments have enabled the RILIS operators to conduct in-source laser spectroscopy experiments, one of the most demanding objectives, remotely from the newly commissioned control room, representing a significantly improved and ergonomic work environment. In addition to permitting remote operation, the increased automation of the system has enabled the transition from shift work to monitored on-call operation as the standard for 2015.