From the actinides and beyond down to the tiniest masses: On the exotic “chemical” nuclear isomer in 229Th, an excursion to the heaviest known elements, and the ECHo project on the electron neutrino m
Prof. Dr. Christoph E. Düllmann (Institut für Kernchemie, Universität Mainz, HIM Mainz und GSI/Darmstadt)

Long-lived transuranium isotopes are central in the study of a variety of hot physics topics. The institute of nuclear chemistry has decade-long expertise and suitable infrastructure for handling these exotic substances, which are often available only in very limited amounts.
In my seminar, I will first discuss current research on thorium-229, in which a long-lived metastable nuclear state at the unusually low excitation energy of around 10 eV exists that is thought to provide a basis for the development of an ultra-precise “nuclear” clock. This provides the only known example of an atomic nucleus that is accessible using laser-based techniques and is also in the focus of a new joint project among QUANTUM, the Institute of Nuclear Chemistry, and HIM.
I will then briefly describe synthesis and study of nuclear, atomic and chemical properties of elements beyond the actinides, which can be produced at accelerator facilities like GSI Darmstadt at the single-atom-level.
Finally, I will introduce the ECHo-project aiming at the determination of the electron neutrino mass via high-precision calorimetric measurements of the electron capture-spectrum of the artificial radioisotope holmium-163, which is produced and separated in a joint effort between the Institute of Nuclear Chemistry and QUANTUM.