PLATAN 2024 - Merger of the Poznan Meeting on Lasers and Trapping Devices in Atomic Nuclei Research and the International Conference on Laser Probing

Laser spectroscopy of fermium-255 at the RISIKO mass separator facility

11 Jun 2024, 14:50

20m

A102 (Agora, University of Jyväskylä, Finland)

Oral Presentation Plenary

Speaker

Mr Matou Stemmler (Johannes Gutenberg Universität Mainz, 55099 Mainz, Germany)

Description

Laser spectroscopy provides information about the fundamental properties of atomic and nuclear structure of the constituents of matter. Measurements are of general importance all along the nuclear chart but are specifically thrilling for the heavy actinides and superheavy elements, where data is sparse and theoretical descriptions can be tested. For an extensive measurement campaign at the RISIKO mass separator facility at the Institute of Physics at Johannes Gutenberg University Mainz, samples of the anthropogenic isotope ${}^{255}$Fm (Z=100) with $10^8$ to $10^9$ atoms each were made available. They were used for studies on the atomic level structure, ionization potential, and hyperfine structure in fermium. The samples initially originate from a ${}^{254}$Es sample that was produced at the HIFR high flux research reactor at the Oak Ridge National Laboratory, Oak Ridge (USA) by neutron breeding. The sample was subsequently re-irradiated at the Institut Laue-Langevin reactor in Grenoble (F) to produce suitable amounts of ${}^{255}$Es (half-life: 39.8 d), which decays to ${}^{255}$Fm (20.07 h) via $\beta^-$ decay, and chemically separated after appropiate ingrowth. This presentation will focus on the atomic structure studies of ${}^{255}$Fm, discussing new three-step laser ionization schemes. Rydberg level convergences were studied and the accuracy of the ionization level was improved.

Presentation materials

Presentation Matou Stemmler

Matou Stemmler PLATAN.pdf