Study of surface ionization and LASER ionization processes using the SOMEIL ion source. Application to the Spiral 2 Laser Ion Source development
Résumé
A prototype ion source, called SOMEIL (Source Optimisée pour les Mesures d'Efficacité d'Ionisation Laser) is constituted by a heated crucible filled up with the element to be ionized by surface ionization. That one is coupled with the ionizer tube made in the studied material. Within another oven is placed the element that is ionizing with the LASER beams. Temperatures of the ionizer tube and of each sample are independently tunable. The device is installed on a mass separator. The ionization efficiencies are calculated from estimation of the flow of atoms running out the ionizer tube. After using conventional material (Ta, Mo) the studies are focused on ceramics (realized by SPCTS Limoges) presenting a low work function to minimize the surface ionization and a high capacity to survive at temperature around 2000°C. Values of ionization efficiencies and work functions will be presented for the different materials mentioned above as well as the early beam characteristics of the LASER Ion source for the SPIRAL2 project.