Freiburg 2024 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 41: Precision Spectroscopy of Atoms and Ions V / Ultra-cold Plasmas and Rydberg Systems II (joint session A/Q)
A 41.1: Vortrag
Freitag, 15. März 2024, 14:30–14:45, HS 1098
Laser Spectroscopy of Californium-253,254 — •Sebastian Berndt for the Fermium collaboration — Johannes Gutenberg Universität Mainz, 55099 Mainz, Germany
Laser resonance ionization spectroscopy (RIS) is an efficient and element-sensitive technique to study the atomic and nuclear structure of transuranium elements. We present recent activities at the RISIKO mass separator at Johannes Gutenberg University Mainz (JGU) regarding laser spectroscopy of the exotic isotopes 253,254Cf. Here, theoretical predictions point to a relevant role of 254Cf in kilonova events associated with r-process nucleosynthesis in the cosmos. For this study, targets of 244−248Cm were neutron-irradiated at the High Flux Isotope Reactor, Oak Ridge National Laboratory (ORNL) to breed 253,254Es, which was chemically separated at ORNL’s Radiochemical Engineering Development Center. This sample was shipped to JGU via Florida State University and then sent to Institut Laue-Langevin for a second irradiation with thermal neutrons to produce 255Es (39.8 d). As the sample also contained about 109 atoms of 252Cf, this was in addition transmuted to 253,254Cf. The hyperfine structure of the 420 nm ground state transition in 253Cf as well as the isotope shift of 254Cf in the 417 nm and 420 nm ground-state transitions were investigated with high resolution RIS, giving access to the nuclear ground-state properties.
Keywords: laser spectroscopy; californium; exotic isotopes; isotope shift; hyperfine structure