Speaker
Description
Actinide isotopes play a crucial role in various scientific research initiatives, serving as targets for accelerator-based irradiation experiments, as targets for laser spectroscopic investigations aimed at exploring atomic and nuclear properties, as laser ablation sources or as recoil ion sources for alpha-decay daughter nuclides. Each experiment demands specific parameters such as sample thickness, geometry, (radio)chemical purity, and backing material. Consequently, tailored targets are essential for each experiment.
At the Joahnnes Gutenberg University Mainz, Germany, various production techniques are employed, such as elec-trochemical deposition, Drop-on-Demand printing or spin-coating. All these methods are constantly being further developed and refined to improve the yield and quality of the desired samples and to adapt to new requirements. The development process often commences with preparatory work using inactive lanthanides as chemical homologs for the actinides. Subsequently, neutron activation of the lanthanides in the TRIGA Mainz research reactor is often performed, resulting in radioactive lanthanide tracers (e.g. Tb-160). This enables the application of radiochemical characterization methods, including gamma spectroscopy and radiographic imaging. The optimized procedure is then applied to the desired actinide isotopes, some of which are highly valuable due to their limited availability. Additional characterization methods for the finished samples include alpha spectroscopy, conventional weighing with a µg balance, optical microscopy as well as scanning electron microscopy with energy dispersive x-ray spec-troscopy.
To expand the range of available actinide isotopes, tailored irradiation of suitable isotopes is performed, e.g. in the high-flux reactor of Institute Laue Langevin (ILL) in Grenoble, France. This way the nuclides Cm-242 and Bk-249 were made available recently.
This presentation provides an overview of diverse production and characterization methods, accompanied by a detailed discussion of specific examples from ongoing projects.