Berlin 2014 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 53: Precision measurements and metrology III (with Q)
A 53.2: Vortrag
Freitag, 21. März 2014, 11:00–11:15, DO24 1.101
Growing and characterisation of (thorium-doped) calcium fluoride crystals for a solid-state nuclear clock — •Matthias Schreitl1, Georg Winkler1, Christoph Tscherne1, Simon Stellmer1, Philipp Dessovic2, Peter Mohn2, Robert Jackson3, and Thorsten Schumm1 — 1Vienna Center for Quantum Science and Technology (VCQ), Atominstitut, Technische Universität Wien — 2Center for Computational Materials Science, Technische Universität Wien — 3School of Physical and Geographical Sciences, Keele University
The isotope 229Th is predicted to provide a unique low-energy excited nuclear state situated only 7.8±0.5 eV [1] above the ground state, opening the possibility to access nuclear physics with lasers. An estimated lifetime of hours [1] makes this narrow transition an excellent candidate for a new time standard.
The transition energy still remains to be determined with higher precision. Our experimental approach is based on embedding 229Th (>1014 nuclei) in the UV-transparent crystal structure of Calcium fluoride (CaF2).
We present progress in CaF2 growth in order to produce single crystals which are transparent in the relevant wavelength region. As the relevant isotope 229Th is radioactive and only available in very small quantities, preliminary measurements are carried out with the stable isotope 232Th. Here, we investigate the implantation of thorium ions into the crystal lattice and how this affects the transparency.
[1] B. R. Beck et al., Phys. Rev. Lett. 98, 142501 (2007)