Yudai Shigekawa, a PhD student from Osaka, spent a year with the Vienna group. Today, almost exactly one year after his arrival, he disassembled the experimental set-up again, ready to be shipped back to his home university.
Yudai constructed an experiment to investigate the decay of U-233 into Th-229. The U-233 sample was sandwiched in between an alpha detector (for measuring alpha particles with high energy and time resolution) and an MCP (to perform spectroscopy on low-energy electrons). The experiment used coincidences between alpha particles and IC electrons to search for the IC decay channel of the Th-229 isomer, and to measure the isomer energy. Over the course of the year, Yudai brought a lot of knowledge into the group, especially with regards to alpha- and electron measurements, and in the preparation of samples. His research stay also included visits to nuClock partners in Munich and nuClock associates at GSI.
Yudai, thanks a lot for staying with us!
No joke: there exist peer-reviewed journals on arts! The publications look just like science publications: title, author list, abstract, acknowledgements, list of reference… plus the well-beloved discussions with reviewers. Anyways, the most reputated journal covering the interface between science, technology, and arts is probably Leonardo Magazine, published by MIT Press. This is where we published a study on one of the two projects that nuClock associate Kerstin Ergenzinger is currently working on. Please find the link here (or download in the “Publications” section), and an accompanying audio blog post here.
If you want to learn more about the artworks, Kerstin has put a number of photos and videos on her webpage. Kerstin’s work is supported by Daniel Canty, a poet based in Montreal. Check out his webpage as well!
If you want to see the installations in real life, plan for one of the following exhibitions:
Over the two years, the LMU Munich group has established the detection of internal conversion (IC) electrons as a successful technique to detect the Th-229 isomer. This scheme as already been used to measure the half-life of the isomer in the neutral charge state, but the really important experiment, a measurement of the isomer energy, is still pending. Such an experiment would need to measure the kinetic energy of the IC electron released in the isomer decay. The LMU team just made an important step towards this goal by laying out the theoretical foundation of such an experiment. The publication appeared yesterday in The European Physical Journal A., it is fully Open Access and can be found here.
A new PhD student joined the nuClock team! Kjeld Beeks from Eindhoven University of Technology just started his PhD in the Vienna group. He will work towards optical excitation and optical detection of the Th-229 isomer transition. Good luck with this challenging work, Kjeld!
Adriana’s theory group just published two new papers, both of which might have a significant impact on experiments building on the Th-229 isomer.
The first paper is a study on a new optomechanical system, which interfaces optical fields and X-rays via an optical cavity. In short, one mirror of an optical cavity is formed by a micro-cantilever, which bears a layer of Th-229 nuclei. These can be excited by X-rays, which impart momentum to the cantilever and change its quantum state, thereby changing the cavity field: a coupling between the optical and X-ray regime! The paper had already been around on the arXiv and has now been published with Sci. Rep., please find the paper here.
The second paper is of purely theoretical nature and a collaboration with Nikolay Minkov from Sofia, Bulgaria. It discusses a new approach to model the lowest nuclear states in Th-229 and arrives at M1 and E2 transition rates between the isomer and the ground state that are markedly different (substantially smaller) compared to all previous models. Among other explanations (strong IC, isomer energy larger than expected, …), such a small coupling could potentially explain why the optical excitation and de-excitation of the isomer was not observed in past experiments. This work has been accepted for publication with Phys. Rev. Lett. and is already available on the arXiv now.
Congratulations to Adriana and her team!