Neon soft x-ray lithography source based on low energy fast miniature plasma focus device

Plasma emissions can be intense source of high energy radiations and can serve as a source for soft x-ray lithography however; it is a complex phenomenon which is substantially influenced by the performance of the associated components such as electrical circuit parameters and filling gas parameters of the plasma focus device. Fine tuning of these parameters can determine the dominant energy emitted as well as their emission efficiency. This can be effectively accomplished when the characteristics of their influence on the plasma dynamics is well understood. For this purpose, experimental analysis were done to study the influence of synchronous operation of Pseudo Spark Gap (PSG) switches on current pinch and X-ray emission, influence of operating gas pressure, percentage of dopant added and the presence or absence of cathode rods on plasma dynamics and X-ray emission. Extensive imaging of the plasma dynamics was done using laser Shadowgraphy technique and the current derivative and X-ray signals were also simultaneously monitored using Rogowski coil and BPX65 silicon PIN photodiodes respectively. Our results deduce the tolerable extent of asynchronisation that does not deteriorate the pinching and the X-ray. The experimental results also infer that the lower operating gas pressure regime is suitable for hard X-ray (>2500 eV) (HXR) emission while higher pressure is suitable for soft X-ray (900 - 1600 eV) (SXR) emission. The obtained images evidently reveal the dependence of symmetry of plasma sheath on the proportion of dopant added and the influence of cathode rods on density, symmetry and curvature of plasma sheath with consequential effect on x-rays emitted from plasma source.