Trapped Ion Chain Thermometry and Mass Spectrometry through Imaging

TL;DR

This paper introduces a non-destructive imaging-based thermometry and mass spectrometry method for trapped ion chains, enabling precise temperature and composition measurements through spatial imaging of ion motion.

Contribution

It presents a novel spatial-imaging technique for ion thermometry and mass spectrometry that does not require Doppler cooling scans, enhancing analysis of mixed-ion chains.

Findings

Spatial extent correlates with ion temperature.

Center-of-mass resonance frequency can be inferred from spatial spread.

Technique improves understanding of sympathetic cooling and ion mass spectrometry.

Abstract

We demonstrate a spatial-imaging thermometry technique for ions in a one-dimensional Coulomb crystal by relating their imaged spatial extent along the linear radiofrequency ion trap axis to normal modes of vibration of coupled oscillators in a harmonic potential. We also use the thermal spatial spread of bright ions in the case of a two-species mixed chain to measure the center-of-mass (COM) resonance frequency of the entire chain and infer the molecular composition of the co-trapped dark ions. These non-destructive techniques create new possibilities for better understanding of sympathetic cooling in mixed-ion chains, improving few-ion mass spectrometry, and trapped-ion thermometry without requiring a scan of Doppler cooling parameters.