Humboldt-Universität zu Berlin - Mathematisch-Naturwissen­schaft­liche Fakultät - Experimentelle Elementarteilchenphysik

Highly Charged Ion Clocks

High-precision clocks are based on vibrational modes of molecules (molecular clock) or electronic transitions in atoms or ions (atomic or ion clock). So-called highly charged ion clocks (HCI clocks) are predicted to be very sensitive instruments in searches for ultra-light dark matter particles since the outer electrons are closer to the nucleus and strongly impacted by relativistic corrections.

The group at HU conducts research on HCI clocks based in the element Californium. A Californium clock is one of up to seven clocks in the planned QSNET clock network.


An HCI clock consists typically of a source for the generation of ions (e.g. an EBIT (eletron beam trap)), a beam line for the selection of the right charge state, a particle trap for storage of the ions, and lasers for the cooling and manipulation of the stored ions. The image shows laboratory work on an EBIT (purple and black).