Jose Luis Henares crowns fellowship with PhD degree
Jose Luis Henares, LA³NET Fellow hosted by GANIL (France) has been awarded the doctoral degree from the University of Caen. The dissertation took place on 8th March 2016 at GANIL.
In his doctoral thesis the now Dr. Henares presents the development of a Resonant Ionization Laser Ion Source (RILIS) at GANIL facility. RILIS is a selective ion source technique which is based on a step-wise resonant excitation process where the elements of interest are ionized via atomic resonant excitation by laser radiation. The off-line RILIS test bench at GANIL consists of three tunable titanium:sapphire lasers and a hot-cavity ion source. In this work a new three-step Zn ionization scheme was developed and the already known ionization schemes for Sn have been compared in order to identify the best ionization scheme for titanium:sapphire laser systems. Furthermore, several configurations of the ion source geometry were tested (two diameters and two lengths) in order to provide an optimal ionization efficiency and ion beam emittance. An increasing of the ionizer diameter was found to enhance the production of laser ionizer elements, while no enhancement was observed by modifying the ionizer length. The time-of-flight of the generated ions was also studied for the different ion source configurations at several temperatures. In addition, a technique to measure the convolution of the spatial and energetic spread of the ion bunches at the detection point was developed. Finally, two contamination reduction techniques were studied: Firstly, the ions trajectories through the ion source cavity can be modified by the electric field generated due to resistive heating. Therefore, a study of the appropriate configuration of the electric field direction was performed to reduce the alkali contamination of the ion beam. Secondly, a low work function material was tested in order to reduce the production of alkali contaminants and molecular sidebands generated inside the ion source.