Anharmonic contributions in real RF linear quadrupole traps

TL;DR

This paper investigates how anharmonic terms in RF quadrupole traps affect large ion cloud storage, analyzing different geometries to optimize trap design using simulations and potential fitting.

Contribution

It introduces a method to evaluate anharmonic content in trap geometries, aiding the design of traps suitable for large ion clouds.

Findings

Identifies trap geometries with minimized anharmonic effects.

Provides a simulation-based approach for trap optimization.

Analyzes potential distribution within the trap volume.

Abstract

The radiofrequency quadrupole linear ion trap is a widely used device in physics and chemistry. When used for trapping of large ion clouds, the presence of anharmonic terms in the radiofrequency potential limits the total number of stored ions. In this paper, we have studied the anharmonic content of the trapping potential for different implementations of a quadrupole trap, searching for the geometry best suited for the trapping of large ion clouds. This is done by calculating the potential of a real trap using SIMION8.0, followed by a fit, which allows us to obtain the evolution of anharmonic terms for a large part of the inner volume of the trap.