Rostock 2019 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 35: Precision Spectroscopy of atoms and ions
A 35.16: Poster
Donnerstag, 14. März 2019, 16:15–18:15, S Fobau Physik
Laser spectroscopic characterization of the nuclear clock isomer 229mTh — •Johannes Thielking1, Maksim V. Okhapkin1, Przemysław Głowacki1, David-Marcel Meier1, Lars von der Wense2, Benedict Seiferle2, Christoph E. Düllmann3,4,5, Peter G. Thirolf2, and Ekkehard Peik1 — 1Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany — 2Ludwig-Maximilians-Universität München, 85748 Garching, Germany — 3GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany — 4Helmholtz-Institut Mainz, 55099 Mainz, Germany — 5Johannes Gutenberg-Universität, 55099 Mainz, Germany
An optical clock based on the transition between ground state and low-lying isomer in the nucleus 229Th would be highly immune to field-induced frequency shifts and a sensitive probe of temporal variations of fundamental constants [1]. We recently performed the first measurement of the nuclear magnetic dipole and electric quadrupole moments and the mean square charge radius of the isomer [2]. This was achieved via high-resolution laser spectroscopy of the hyperfine structure of trapped 229Th2+ ions, loaded from the α decay of 233U. We are now preparing an experiment to investigate the excitation of the nucleus via electronic bridge and NEET processes [3,4] in the energy range from 7.2 to 10.2 eV, using two-step laser excitation in Th2+.
[1] E. Peik, Chr. Tamm, Europhys. Lett. 61, 181 (2003).
[2] J. Thielking et al., Nature 556, 321-325 (2018).
[3] S. G. Porsev et al., Phys. Rev. Lett. 105, 185501 (2010).
[4] F.F. Karpeshin et al., Nucl. Phys. A, 654, 579 (1999).