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Abstract

Certain highly charged ions (HCIs) exhibit enhanced sensitivity to fundamental interactions due to the
specifics of their level structure, enabling improvement in atomic clocks and frequency metrology. This
allows more precise tests of fundamental physics than achievable with atoms or singly charged ions,
e. g. in the search for a possible time variation of the fine-structure constant alpha. Their narrow optical
transitions make them suitable targets for quantum metrology, as recently demonstrated for Ar¹³⁺. Anelectron beam ion trap (EBIT) is used to produce ions in the desired charge states. However, the high
temperature within EBITs requires a transfer of the HCIs into a cooling trap to perform high-resolution
spectroscopy. This work presents a setup comprising an EBIT and a beamline suitable for transfer,
bunching, precooling and deceleration of extracted HCIs. In the EBIT, an electron beam is electrically
accelerated and magnetically compressed to sequentially ionize neutral atoms injected into the trap center
to generate HCIs. The ion optics, diagnostic elements and a decelerating/pre-cooling unit of the beamline
prepare them for re-trapping. Time-of-flight measurements were performed to determine the charge state
distribution of the extracted ions. Furthermore, a retarding field analyzer allowed the determination of
their mean kinetic energy as well as their energy spread, which has been subsequently reduced in the
pre-cooling unit.