Optimization of a Water Window Capillary Discharge Radiation Source

Abstract

Computer modeling of a fast electrical discharge in a nitrogen-filled alumina capillary was performed in order to discover discharge system parameters that lead to high radiation intensity in the so-called water window range of wavelengths (2–4 nm). The modeling was performed by means of the two-dimensional RMHD code Z*. The time and spatial distribution of plasma quantities were used for calculating the ion level populations and for estimating the absorption of the 2.88 nm radiation line in the capillary plasma, using the FLYCHK code. Optimum discharge parameters for the capillary discharge water window source are suggested. The heating of the electrodes and the role of capillary channel shielding were analyzed according to the Z* code.