Fig. 3: Electron spectrometer calibration with two independent exposures.
From: Unifying frequency metrology across microwave, optical, and free-electron domains
a Deviations of the calibration markers at multiples of the photon energy from the nominal energy of the spectrometer for Exposures (Exp.) 1 and 2. Shaded areas correspond to error bars. Inset: a schematic depiction of obtaining the energy solution from the electron spectrum. b–d First, second, and third-order components of the polynomial fits of the energy solutions (pixel-to-energy mappings) for the two exposures. The first-order components illustrate the calibrated average dispersion. e Histogram of the pixel-wise root-mean-square deviation between the energy solutions of the two exposures. Red curve represents a normal distribution fit with a standard deviation of 20.9 meV.
