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Welcome to the Website of nuClock!

nuClock is a European project headed for an ambitious goal: the development of a scientific clock that reaches a much higher precision compared to the best clocks that are operated today in some of the world’s finest laboratories. While such clocks use the electrons of an atom as the “pendulum”, we will use the nucleus of a very special atom – Thorium-229 – for setting the rhythm. Once we get our clock working, it can be employed aboard navigation satellites, it can help to synchronize networks, and it might lead astronomers to a better understanding of the universe.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 664732. It will run from 2015 to 2019. Stay with us: it’s sure going to be exciting!

European_Comission

NEWS

Lorentz symmetry tested by PTB partner

In his Special Theory of Relativity, Einstein formulated the hypothesis according to which the speed of light is always the same, no matter what the conditions are. It may, however, be possible that – according to theoretical models of quantum gravitation – this uniformity of space-time does not apply to particles. Physicists have now tested this hypothesis with a first long-term comparison of two optical ytterbium clocks at the Physikalisch-Technische Bundesanstalt (PTB). With these clocks,…
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nuClock on (summer school) tour

Optical clocks with trapped ions and the Th-229 nuclear clock will be a topic at several summer schools this year, featuring nuClock partner E. Peik as lecturer: European Frequency and Time Seminar EFTS 2019 1-5 July 2019, Besancon, France International School of Physics "Enrico Fermi" COURSE 206 - NEW FRONTIERS FOR METROLOGY: FROM BIOLOGY AND CHEMISTRY TO QUANTUM AND DATA SCIENCE, 4-13 July 2019, Varenna, Italy Les Houches predoc school on Interaction of Light and Cold Atoms 30…
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Comprehensive study of electronic structure of Th1+ in the isomer energy region

Using 2-photon resonant laser spectroscopy, the PTB team identifies 166 previously uncharted electronic states of the Th1+ ion in the energy range between 7.8 and 9.8 eV. The observed levels can be relevant for the excitation or decay of the 229mTh isomeric nuclear state which lies in this energy range. The high density of electronic levels promises a strongly enhanced electronic bridge excitation of the isomer in 229Th. Read more on arXive.
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Vienna team demonstrates all-solid-state VUV frequency comb in teamwork with TOPTICA

A VUV frequency comb seems to be a promising candidate for performing high-resolution spectroscopy on the Th-229 nucleus. Such a device up-converts the frequency of a stabilized femtosecond laser from the infrared to the ultraviolet using a process called "high-harmonic generation" (HHG). This process is usually performed in noble gas jets. It requires extreme optical field amplitudes, which usually can only be realized when enhancing the laser power in a passive built-up cavity. The Vienna team…
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Optical pumping to the Th-229 isomeric state demonstrated

While several groups make progress on determining the exact energy of the Th-229 isomer, the uncertainty is still too large for a direct optical excitation with a narrow-band source to be successful. Most approaches use the U-233 alpha-decay as a means of populating the isomer with a 2% probability. This alpha decay is however a violent process, transferring >80 keV of recoil energy to the "new-born" Th-229 ion, which makes further manipulation a formidable task. A Japanese consortium, with support…
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New paper on collective effects in Thorium-doped crystals

Brenden, Wen-Te, and Adriana of MPIK in Heidelberg have released a new paper investigating collective effects that could occur in Thorium doped crystals when excited by narrow-band coherent pulses. Here's the link to the paper. A variety of schemes are discussed with the goal of creating unique signatures of excitation which can be used to determine the detuning of the exciting laser pulses from 229Th nuclear transition energy. Other details such as multi pulsed excitation, pulse shape, phase shifting…

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Theoretical and experimental work leads to a redetermination of the Th-229 isomer charge radius

Marianna Safronova and colleagues from the Univ. of Delaware and from the Kurchatov Institute in St. Petersburg have performed new atomic structure calculations for Th+and Th2+that are used to relate measured spectroscopic isotope shifts to differences of the nuclear charge radii. Such calculations are notoriously difficult for these thorium ions because of strong configuration mixing of the electrons. Combined with experimental data on isotope shifts in Th+from 227Th to 232Th, measured at KfK Karlsruhe…
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Hertha-Sponer-Prize for Adriana Pálffy-Buß

Adriana Pálffy-Buß is awarded the prestigeous Herta-Sponer-Prize from the German Physical Society (DPG) for her pathfinding reasearch on quantum effects in the interaction of atomic nuclei with X-ray pulses. Here's the link to the press release. Congratulations Adriana!
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