May 2025
From nuclear chemistry in Mainz to physics at CERN
"My heart beats strongly for the natural sciences, for both physics AND chemistry. As a PhD student in nuclear chemistry, I am able to combine both: I am researching the production of radioactive ions – such as atomic thorium (Th+) and thorium monofluoride (ThF+) – within the framework of the TACTICa project. These ions are caught in a Paul trap for quantum logic spectroscopy, in order to search for physics beyond the Standard Model. This involves a linear Paul trap, similar in function to ion traps used in the quantum computing group of Professor Schmidt-Kaler.
The radioactive ions are produced by laser ablation of so-called targets in ultra-high vacuum, with small, multiply charged molecular ions or large, singly charged clusters being found depending on the sample material and laser energy. This research merges physics and chemistry, as new insights into the chemistry of actinides and their molecules in the gas phase can be gained and at the same time the limits of the standard model of physics can be explored anew, should these ions one day be used as quantum sensors for the detection of dark matter.
©: Jonas Werner Photography
The chemically tailored targets for such experiments are produced in the radioactive laboratory of Prof. Dr. Düllmann. Our work is not limited to Mainz and the TACTICa project: Various researchers collaboratively produce samples for research institutions worldwide, including CERN. At the world’s largest particle physics research center, not only are PRISMA+ detectors used, but for the first time, a protactinium sample from the mentioned radioactive laboratory was produced and used in experiments at CERN-ISOLDE. The collaboration with CERN was a real highlight for me, as I not only produced the required sample for the experiment but also had the opportunity to participate in the experiment in Geneva. It was truly fascinating to see how our group contributed significantly to a successful ISOLDE experiment and how the first protactinium ion beam was generated – a milestone!
To my great delight, this experiment once again demonstrated that the interplay between physics and chemistry opens up new paths in both disciplines. Research in nuclear chemistry offers endless possibilities, and I look forward to further discoveries!"
Jonas Stricker originally comes from the field of chemistry. After completing his bachelor's degree in Bonn, he switched to nuclear chemistry in Mainz for his master's degree in 2020. He started his doctorate in Prof. Dr. Christoph Düllmann's working group at the beginning of 2023 and is bridging the gap between chemistry and physics with his research.