Mainz 2022 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 71: Structure and Dynamics of Nuclei XIII

HK 71.3: Vortrag

Donnerstag, 31. März 2022, 16:45–17:00, HK-H7

Nuclear structure investigations on ^253−255Es by laser resonance ionization spectroscopy — •Steven Nothhelfer for the Einsteinium collaboration — Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany — Helmholtz-Institut Mainz, 55099 Mainz, Germany — GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany

Experimental data on the hyperfine structure splittings and isotope shifts of spectral lines in transuranium elements reveal valuable information about the structure of their atomic nuclei. In this poster we will present results of laser resonance ionization spectroscopy performed on the rare isotopes ^253−255Es at the RISIKO mass separator in Mainz. With small sample sizes ranging down to fg, the prominent 351.5 nm ground-state transition (5f¹¹7s² → 5f¹¹7s7p) was measured in all three Es isotopes. Furthermore, four additional ground-state transitions were measured in ²⁵⁴Es. Hyperfine structure analysis resulted in spin values of I(²⁵⁴Es) = 7 and I(²⁵⁵Es) = 7/2. Nuclear magnetic dipole moments as well as spectroscopic electric quadrupole moments were derived from the extracted hyperfine coupling constants. The literature value of the nuclear magnetic dipole moment for ²⁵⁴Es obtained from angular anisotropy measurements of ²⁵⁴Es α-radiation [1] deviates from our more precise value of this quantity.
Further measurements are planned on ²⁵⁴Es using a new high-resolution gas-jet apparatus [2]. Most recent results will be presented.
[1] N. Severijns et al., Phys. Rev. C 79 (2009), 064322. [2] S. Raeder et al., Nucl. Instrum. Methods. Phys. Res. B 463 (2020), 272-276.