Demonstration experiments for the electronic detection of trapped ions in a linear Paul trap

Abstract

We demonstrate a simple electronic detection method for trapped ions in a linear Paul trap. Singly charged calcium ions are confined in a linear Paul trap and are driven by an ac electric field at their secular frequency. The collective motion of the ions causes induced current on the trap electrodes, and the current signal is detected by a tuned circuit. This paper describes the design of the tuned circuit and the performance of this detection method. This method can be applied to various species of ions in different trap geometries. It serves as a simple tool to probe the existing ions in the trap, while in some cases, optical detection is not feasible. This method is particularly suitable for demonstration in teaching laboratories where the ion trap systems and detection circuits can be constructed by undergraduate students.