title: Trapped ion chain thermometry and mass spectrometry through imaging.
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 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.
authors: Northwestern University, Evanston, Illinois, USA. Present address: The Rowland Institute at Harvard, Cambridge, Massachusetts, USA.. rvaishnavi85@gmail.com.
authors: Vaishnavi
authors: V
authors: Rajagopal
authors: Northwestern University, Evanston, Illinois, USA. Present address: Clemson University, Clemson, South Carolina, USA.. jmarler@clemson.eu.
authors: Joan P
authors: JP
authors: Marler
authors: Northwestern University, Evanston, Illinois, USA.. markkokish2019@u.northwester.edu.
authors: Mark G
authors: MG
authors: Kokish
authors: Northwestern University, Evanston, Illinois, USA.. b-odom@northwestern.edu.
authors: Brian C
authors: BC
authors: Odom