A theory of the magnetic field diffusion is developed in order to explain high-energy x-ray emission observed in vacuum spark plasmas. The acceleration mechanism is based on the intense induced electric field due to an abrupt inductance change when the plasma column expands from its pinch radius to a large radius. According to this magnetic field diffusion model, high-energy electrons are well collimated at the axis. In addition, the electron energy in this collimated flux can be easily more than 20 times the electrode voltage, which generates high-energy x-ray radiation by interaction with the dense plasma.
A 1-kJ vacuum-spark device has been developed as a pulsed X-ray source for applications in the field of microlithography, microscopy, flash radiography, etc. The optimization works for the pulsed soft-X-ray emission are presented. The optimization was made in two steps: 1) X-ray emission maximization and 2) X-ray emission reproducibility. For the X-ray emission maximization, the changed parameters were the main capacitor energy, the anode-cathode geometry, the anode material, and the trigger pulse amplitude. The best combination is [u]1 kJ for the main capacitor energy[/u], a [u]conical shape for the anode[/u], [u]6-12 mm anode-cathode separation[/u], [u]iron for the anode material, and 14-15 kV for the trigger pulse amplitude[/u]. In these conditions, energies of up to 10 J per pulse are obtained in the 3-40 keV range for the X-ray pulses. In order to have a good reproducibility, [i]a high-power, very fast, high-voltage trigger pulse is required.[/i] To fulfill these conditions, a pulse transformer and an air spark gap were added to the initial triggering device (a magnetic pulse compression circuit). With the new trigger pulse (20 J per pulse, 50-ns rise-time, 22-kV amplitude in an open circuit), an acceptable X-ray emission reproducibility was obtained The take away: success is all in the way you all build your spark. On Thu, Jan 10, 2013 at 1:16 AM, Eric Walker <[email protected]> wrote: > I wrote: > > I got ahold of Ron at physics.stackexchange.com and asked some questions >> to help bring his theory down to the realm of hobbyists [2]. Some >> interesting points came out of that chat, including these: >> > > Another interesting point I forgot to mention is that Ron suggested > somewhere that you might see a large energy release when loaded Pd/D is > irradiated with x-rays (possibly a dangerous amount of energy). This > suggests some fun experiments that could be attempted in an adjacent room > or in one's backyard, if one could get ahold of a x-ray cathode ray tube. > > Eric > >
