Dynamic properties of ultra-fast pulsed capillary discharge devices

The authors report a fast pulsed capillary discharge device, which combines the features of transient hollow cathode discharge with the inherent characteristics of the capillary discharge to guarantee radiation in the VUV and soft X-ray region with ns rise time. Various combinations of discharge parameters differing in capacitance of the cell, in the aspect ratio and in the pressure of the filling gas have been studied in order to optimize this table top source to technical and scientific backlighting applications. After rapidly igniting the discharge by an electron beam resulting from the hollow cathode effect, the plasma emits bright radiation in the soft-X-ray and VUV region, with λ ge 3 nm. Using Argon as the filling gas, the spectrum consists of Ar VII to Ar X lines during the period of extreme emission. Energy losses due to radial thermal conduction effect shorten the radiation pulse. A series of VUV spectra which are detected by a calibrated spectrometer covers the period of the discharge and allows a quick estimation of discharge parameters. The spatial evolution of the radiation source is studied using a time resolved Slit-Wire camera. Two different regimes of wall and gas dominated discharges have been identified based upon the spectra obtained, under different operating pressures