Extended Data Fig. 1: Plots for the dip width evaluation.

a) Fitting results for a singe proton. In gray are the FFT data of 5 spectra, in blue the corresponding fit functions, resulting in a single proton dip width of (0.64 ± 0.06) Hz. b) Results of an evaporation measurement for dip width calibration, plotting the dip width against the corresponding proton number. In gray the data, in blue a linear fit for future data evaluation with (0.63 ± 0.01) Hz ⋅ x + (0.09 ± 0.13) Hz. The single proton value was taken from the results of graph a).