File:Full covariance map of neon.png

English: A covariance map revealing correlations between electrons emitted from neon (and from some N₂ and water vapour contamination). The map is constructed shot by shot from electron energy spectra recorded at the photon energy of 1062 eV, which are shown along the x and y axes after averaging over 480 000 FEL shots. Volumes of the features on the map give relative probabilities of various ionization sequences, which can be classified as: (a) Ne core-core; (b) H₂O core-core, core-Auger, and Auger-Auger; (c) Ne Auger-Auger; (d) Ne valence-valence; (e) N₂ core-Auger; (f) H₂O core-valence; (g) Ne core-Auger; (h) Ne core-valence; (i) double Auger and secondary electrons from electrode surfaces; and (j) Ne main (core) photoelectron line.