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!



Transportable optical Sr clock presented by PTB

Building an optical clock based on the Th-229 nuclear transition is the ultimate goal of the nuClock project. We like to claim that such a nuclear clock will be less sensitive to perturbations (because the nucleus is so much smaller than the orbits of valence electrons), offer a supreme quality factor (because the transition energy is so large, and the lifetime of the isomer is so long), and outperform existing clocks in flat-out all respects (well, we become a little bit emotional sometimes). We…

PhD defense/exam Lars von der Wense

Lars von der Wense, nuClock superhero of 2015, will face his PhD exam on Friday, Feb. 3. Although his chances of success appear rather small, we still wish him all the best 🙂 Good luck, Lars!

New preprint publication

A few days ago, a new manuscript was submitted to the arXiv preprint server. It discusses a new approach to measure (or at least contrain) the Th-229 isomer energy by optically exciting Th+ or Th2+ ions into metastable electronic states, and seeking to observe internal conversion from the excited electronic state to the nucleus. Laser excitation into a suitable metastable state seems to be an intricate process, involving 4 or even 6 resonant lasers. This publication is a joint work by the MPIK Heidelberg,…

In the alpha decay of U-233, how many percent of the atoms go into the Th-229 isomer?

The alpha decay of U-233 is a well-established approach to obtain Th-229 atoms or ions in the isomeric state. In fact, it is the only method to date that has been shown to be capable of populating the isomer. Still, the probability of feeding the isomer has not been measured. A value of 2% is often found in literature, yet retracing how this number was obtained is difficult. We used the available U-233 decay data from the NuDat database and, based on this data, calculated a probability of at least…

Happy New Year 2017

We hope you all had a joyful holiday season. With 2017 just around the corner, nuClock wishes peace, luck, and success in 2017 to all of you: the partners, associates, fans & followers, and all your family and friends. Happy New Year!

"Physics World" 2016 Breakthrough of the Year

Towards the end of each year, the editors of the "Physics World" elect ten experiments or publications that they consider to be the most important scientific breakthroughs of the past year. Although an entirely subjective choice, this "Top-10" list has gained quite some visibility over the past years. To our great delight, the direct detection of the the Th-229 isomer by the LMU Munich group was ranked third among the ten breakthroughs of 2016! Congratulations to Lars, Bene, and Peter from Munich,…

Laser spectroscopy of Th-229 recoil ions

In a joint experiment of the LMU group and the PTB group a first run of laser spectroscopy experiments has been done on trapped Th-229 from the Munich recoil ion catcher, with laser systems and optical detection methods developed at PTB. The measurements should provide crucial information on the nuclear properties of the isomeric state from the hyperfine structure of electronic transitions. The first experimental campaign in October/November this year has proven the joint working of the systems and…

Laser spectroscopy of Nobelium

Nobelium is one of these heavy and short-lived elements at the bottom of the periodic table. It has a  nuclear charge Z = 102 and even its most stable isotope has a half-life of less than a minute. Elements with Z > 100 are called transfermium elements, and so far, no laser spectroscopy has ever been performed on these elements. Last week, Mustapha Laatiaoui and his team reported on the first laser spectroscopy of two nobelium isotopes. They used the GSI facility to produce No-252 and No-254,…