Laser-cooling of ions and ion acceleration in the RF-quadrupole ring trap PALLAS

We report on the commissioning of the table-top RF-Quadrupole storage ring PALLAS*, dedicated to the experimental realization of crystalline ion beams. Images of large prolate Mg-24(+)-ion crystals are presented, operating PALLAS locally as a linear rf-trap and applying laser-cooling, beautifully confirming prior theoretical and experimental work. For few-ion strings, a radial oscillation of the crystal was observed, stabilized only by additional indirectly cooled impurity ions. On the challenging way towards crystalline ion beams, we demonstrate the acceleration of an ion distribution initially at rest, i.e., the very first operation of PALLAS as a storage ring, still to be heavily improved. Further applications, as the systematic investigation of residual gas damping, or sympathetic cooling for, e.g., the mass determination of heavy radioactive isotopes are briefly discussed.