A linear Paul trap to study the equilibrium of charged micron-sized particles in air

Abstract

We describe and use a macroscopic linear quadrupolar trap to explore the trapping and equilibrium properties of charged particles. These devices, when operated to trap atomic ions, are at the core of ion based quantum computer and optical atomic clock. To illustrate the characteristics of few particle trapping, and observe different force balance on a charged particle, a macroscopic linear trap, operating at room condition, is trapping micrometer-sized particles. Compared to atomic or molecular ions, their mass can not be neglected and requires an extra voltage for gravity force compensation. We show how this compensation can be demonstrated experimentally and that the choice of hollow-core glass spheres has the advantage of a good reproducibility of the experiments, that allows one to deduce with good precision the charge-to-mass ratio of the trapped particle.