Figure 5
Ion spectra from xenon gas, zoomed in on high charge states. Comparison for (i) DESC inactive, (ii) attenuated intensities at inactive DESC with filter foil, imitating the transmission of DESC and (iii) DESC active. The time-of-flight measurements were averaged and converted to mass-over-charge ratio. Without DESC, the highest observed charge state was reduced from Xe14+ at full beam to Xe12+ using a 200 nm niobium foil (transmission ∼37%). After iteratively optimizing all mirrors of DESC for highest charge states, 12-fold ionized xenon was also observed, indicating a good alignment of DESC. We note that the total lower ion yield at (iii) is induced by slightly changed positions of the retractable time-of-flight spectrometer, which is not relevant for the appearance of the high charge states. Besides Xeq+, N+ at m/q = 14 from residual gas can also be observed in the `DESC inactive' measurements, which was present only at the beginning of the experiment. |