Characterization of the radiation from a low-energy X-pinch source

Abstract

The explosion of a single wire with a high current pulse has long been established as an excellent source of x-ray radiation. However, experimental analysis of single wire explosions shows that the radiation is emitted from an inhomogeneous plasma consisting of high-density high-energy emitting points located randomly in a low density background column. The X- pinch, in which two or more crossed wires are exploded by a large current pulse driven by a low inductance source, is a good source of soft x-ray radiation in the energy range of 100 eV to 10 keV. The geometry of the crossed wire load ensures that the plasma emitting the bulk of the harder radiation is reproducibly located at the crossing point of the wires. This renders the source ideal for applications such as x-ray microscopy and lithography. Previous work on X- pinches has been carried out using elaborate high-voltage pulsed power generators delivering a brief high current pulse. Results are presented here of a first comprehensive study of X-pinch discharges driven by a low energy (4 kJ), low voltage (30 kV) 9 (mu) F capacitor bank. X- ray emission from X-pinches made from a variety of wires of different sizes and materials is characterized and compared with x-ray emission from single wire discharges. Radiation output is measured for different spectral regimes and information is presented concerning both the spatial and temporal emission of the radiation. Conditions for optimal soft x-ray yield on such low power machines are established.