Upgrade of the reference area of the CERN-ISOLDE Resonance Ionization Laser Ion Source

The Resonance Ionization Laser Ion Source (RILIS) is currently the most frequently used ion source at ISOLDE, thick target ISOL facility. The reference system enables the stabilization and imaging of the laser beams to facilitate the optimization and maintenance of the laser set up, to achieve maximum ionization efficiency for the duration of an experiment. The beams are directed into the ion source cavities of either of the two ISOLDE target stations through windows in the magnetic-dipole mass separators. Wedged quartz plates are positioned in the middle of the laser beam paths between the laser table and the hot-cavity ion sources. Fresnel reflections of the laser beams from the surfaces of the plates are directed back to laser laboratory towards a dedicated reference beam monitoring and stabilization system. Previously, only beams from one separator at a time can be observed, causing a common operational bottleneck where a set-up on another separator could not progress while the RILIS was in operation. The goal of the project is the upgrade of the previous reference area to allow beams from both separators to be stabilized and monitored simultaneously to reduce set-up time between on-line experiments.