Nuclear clocks could make our time measurement even more accurate than atomic clocks. The key to this lies in thorium-229, an atomic nucleus whose lowest excited state has very low energy. A research team from the Kirchhoff Institute for Physics at the University of Heidelberg, TU Wien, Johannes Gutenberg University Mainz (JGU), the Helmholtz Institute Mainz (HIM), and GSI Helmholtzzentrum in Darmstadt has now succeeded in measuring this low energy. Using an extremely accurate detector, it was possible to detect the tiny temperature increase due to the energy released during the de-excitation of the atomic nucleus. This brings the realization of a nuclear clock a big step closer.
In radioactive decay, atomic nuclei spontaneously re-arrange, eject some part of their building blocks, and transform into a nucleus of a different atom. In this process, the new “daughter atom” usually has internally stored energy that is released in the form of