Fig. 3: (Peak-)fluence dependence of the ion yields of Xe at 1325 eV.

a Ion yields of Xe as a function of peak fluence. Theoretical ion yields are volume-integrated with a single (solid lines) or double (dashed lines) Gaussian spatial profile (see Supplementary Discussion S1 for details). Error bars of the experimental data include systematic and statistical errors (see Methods). The theoretical ion yields (both single and double Gaussian cases) are scaled to the experimental asymptotic values. The respective factors as specified next to the curves, with +10 being the reference. b Computed Xe ion yields as a function of fluence without volume integration. c Fluence distribution function in the X-ray focus for different peak fluences, assuming a single Gaussian spatial profile.