Item

Abstract

The Penning trap experiment Alphatrap tests quantum electrodynamics via g-
factor measurements of bound electrons in highly charged ions (HCI). The precision
of the measurements can be improved by cooling the HCI. This thesis describes a
novel and versatile method to sympathetically cool HCIs with laser-cooled beryllium
ions efficiently in high-precision Penning traps. The method is based on increasing
the coupling of two ions stored in separate penning traps by adding an electrical
tank circuit. In a proof of principle measurement this was demonstrated using a
⁸⁴Kr²³⁺ and ⁴⁰Ar¹¹⁺ ion: first, we saw an avoided crossing of the ion modes, and
second, we showed a Rabi oscillation in the energy transfer. Our coupling technique
enables active control of the coupling strength between the ions, so that a coupling
time of τ = 0:856(16) s was achieved. We see this as a possible tool to efficiently
cool a wide range of ion species.
In addition, an active beam stabilization system was installed to reduce fluctuations
of the cooling laser beam position and orientation, and to improve the alignment
of the laser with respect to the beryllium ions. This system was calibrated and
geometric losses of the laser transmission through our Penning trap setup were
estimated.