Fast capillary discharge device for soft x-ray generation in the "carbon-window" and "water-window" spectral regions

The paper presents a compact source of soft X-ray radiation based on a fast capillary discharge developed for "water window" microscopy methods. The central part of the source is the specially designed nanosecond voltage pulse generator capable of operating at a frequency of 600 Hz, with 100 ns pulse duration and energy per pulse 5 J. The discharge is created in a borosilicate capillary non-uniformly filled with gas. The plasma emission spectra obtained for the case of source operation in argon-helium mixture demonstrate well-pronounced lines in the "carbon window" range, in carbon dioxide-lines in the "water window" range. An analysis of the emission spectra in the range of 2-9 nm in cases of different inlet gas pressures made it possible to estimate the degree of ablation of the inner wall of the capillary and to determine the suitable operating pressure range.