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GSI Scientists Participate in Top 10 Discovery

Copyright: Christoph Düllmann, JGU Mainz

Graphical illustration of the nuclear clock



Scientists from GSI are participants in one of the ten most important discoveries of 2016. A publication by a team of researchers led by the Ludwig-Maximilians-Universität München (LMU) and including scientists and engineers from GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, the Helmholtz Institute Mainz (HIM), and the Johannes Gutenberg University Mainz (JGU) is among the most important breakthroughs in physics in 2016. The team’s work is featured as one of the “2016 Top Ten Breakthroughs of the Year” announced recently in Physics World — the magazine of the British Institute of Physics. The experiments in question lay one of the foundations for the development of a nuclear clock with previously unattained precision.

In the article, which was published in 2016, the researchers, some of whom come from the Super Heavy Elements departments at GSI and HIM, report on the first-ever direct detection of the exotic thorium isomer Th-229m. This is a decisive step that brings us closer to being able to build an ultra-precise nuclear clock based on this isomer. Atomic clocks are currently the most precise timekeepers in the world. The record is currently held by a clock that will keep time to within one second in 20 billion years. The team that has just been commended is led by PD Dr. Peter Thirolf and Lars von der Wense from the LMU München and has achieved the first experimental demonstration of an excited state of the thorium-229 isotope that had been sought worldwide for more than 40 years and could help improve the timekeeping precision by a factor of around ten. The researchers reported their findings in the scientific journal Nature. A nuclear clock features a multitude of potential applications, including the search for dark matter and gravitational waves. It would also provide ultra-high sensitivity to detect potential time variations of fundamental constants.

The ten most important “Breakthroughs of the Year” are selected by Physics World every year. The criteria for the list of the ten most important discoveries are the fundamental importance of the research result, a significant advance in knowledge, a strong connection between theory and experiment, and the discovery’s general interest for all physicists.

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Graphical illustration of the nuclear clock
Nuclear clock based on a transition in the atomic nucleus of thorium-229. For the first time, electrons emitted in the deexcitation of the isomer into the ground state could be directly detected.
Copyright: Christoph Düllmann, JGU Mainz