Characterisation of a gas discharge based light source for X-ray microscopy at a central wavelength of 2.88 nm

The X-ray line emission of He-like nitrogen ions in a pulsed discharge plasma is characterised in terms of the use for microscopy. The plasma is ignited in a pseudo spark like electrode geometry with a capacitive stored energy of 10-15 Joule. The resonance transition 1s2-1s2p of the He-like ion species at a central wavelength of 2.88 nm is investigated by means of spatially and time resolved measurements. Special interest is devoted to the admixture of xenon, which leads to a substantial reduction of the emitting plasma in its length and diameter, as well as to the detected temporal discrete emission peaks, occuring during a single discharge cycle. On the basis of time and spatially resolved diagnostics the plasma dynamics is investigated in the context of the light emission within the soft X-ray spectrum on a nanosecond timescale. Resultant a strong axial dynamic is connected with the temporal discrete emission peaks. Due to recorded emission spectra of different gases in the spectral range 1-5 nm, estimates concerning the range of achieved plasma parameters are reasonable