Abstract

We present results from a pulsed capillary ns discharge source, operated in Nitrogen and N/He mixtures, in an alumina capillary 2.1mm long with outer diameter of 6.3mm and inner diameter of 1.6mm The electrical energy stored is 0.5J with peak current of 6kA. Fast charging from an IGBT based pulsed power circuit allows operation at 35-600 Hz with voltages in the range of 18-24kV. Characteristic time-integrated N/He spectra were recorded and analyzed for values of 20-200 angstrom, with clear evidence of He-like Nitrogen emission at 28.8 angstrom, which represents a possible source for water window soft x-ray microscopy. Filtered diode measurements reveal the influence of axial electron beams, generated by hollow cathode dynamics, on the x-ray emission in the range of 300-450 eV. We discuss optimal voltage applied and pressure conditions for soft x-ray generation. Time-integrated MCP images of a filtered slit-wire system delivered clear evidence of full wall detachment with similar to 500 mu m in radial size for the entire emission range and similar to 200 mu m for the emission in the 300-450 eV range.