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 1.98% for the isomer population. The NuDat data was generated by estimating or assuming a set of branching ratios for gamma and internal conversion transitions. The NuDat database can therefore be used as a reference for the 2%-value, but this value is based on estimated (not measured) branching ratios.

A short essay on the topic can be found here, questions and comments to the author are more than welcome!

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, and to their collaborators at GSI, Mainz, and elsewhere!

This year’s number-one went to be the discovery of gravitational waves by the LIGO collaboration. The magazine “Physics World” and the corresponding webpage www.physicsworld.com are published by the British Institute of Physics (IOP), the full story can be found here.

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, deposited a few of these atoms on a filament, then quickly heated the filament to release the atoms into the gas phase, and performed resonance ionization via an intermediate step; the produced ions were then detected. This very efficient spectroscopy and detection scheme allowed the researches to perform the measurements with the veeery small production rate of these atoms.

Mustapha and his team at GSI are associate partners of the nuClock consortium. Congratulations to this beautiful result!

link to the Nature publication

link to the GSI press release

The 2016 Ars Electronica Festival took place last week in Linz: a perfect venue for the first public appearance of nuClock’s art project! Kerstin Ergenzinger presented her past & future work, and Thorsten Schumm took part in a podium discussion on future plans of strengthening the arts/science collaboration in Europe.

Simon Stellmer and Kerstin Ergenzinger on the “Future Innovators Summit” stage, presenting the concept of the nuClock artwork currently under development. (credits: FEAT)

nuClock coordinator Thorsten Schumm (at the microphone) at a podium discussion among researchers, artists, and policy makers. (credits: FEAT)

A few months ago, nuClock joined the FEAT initiative to explore the interplay between arts and sciences. The cooperation with artist Kerstin Ergenzinger of Berlin will come to life at the upcoming Ars Electronica exhibition in Linz, Austria. Ars Electronica is the world’s largest and most influential exhibition of digital art. Held annually since 1979, it is set up as a 4-day festival with a focus on the interface between arts, electronics, and society. The motto of this year’s meeting is “RADICAL ATOMS and the alchemists of our time”: what a picture-perfect setting for our nuClock work! The event will last from September 8 through 10, and is expected to attract 600 exhibitors and 100.000 visitors.

nuClock will be featured on the opening day, Thursday Sept. 8. At first, Kerstin Ergenzinger and Simon Stellmer will have an interview with Annick Bureaud, which will later morph into a video blog. Later, the two will present the concept of nuClock’s first piece of art: an installation that builds on earlier “navigating noise” artwork. In addition, Thorsten Schumm will join a podium discussion on arts and sciences.

To prepare for the exhibition, Simon Stellmer spent a two-day visit at Kerstin Ergenzinger’s studio in Berlin last week. In turn, Mrs. Ergenzinger visited the MLS facility in Berlin-Adlershof, where a joined TU WIEN / PTB experiment is currently prepared to search for the Th-229 isomer transition. This measurement – detecting a faint signal on top of large background noise – is the inspiration for the joint artwork.