A split-ring Paul trap for dipolar excitation of the radial ion motion and ellipticity studies

Abstract

A radial dipolar excitation has been applied to a hyperbolic Paul trap with a segmented ring electrode. In addition, this configuration allowed the generation of an elliptical Paul trap by superimposing the RF trapping field with an electrostatic azimuthally quadrupolar field. The changes in the radial ion motions with respect to the conventional Paul trap are discussed and investigated experimentally. As expected, the formerly degenerated radial eigenfrequencies $\nu_{r}$ of the standard Paul trap split into two separate resonances at $\nu_{x}$ and $\nu_{y}$ , while the axial eigenfrequency $\nu_{z}$ remains unaffected. The new trap design adds flexibility and extends the range of applications of Paul traps.