Nanosecond discharges with runaway electrons and X-rays in atmospheric pressure air, nitrogen, CH4, SF6, xenon, krypton, argon and helium

Diffuse discharges were formed in a highly nonuniform electric field by point-plane gaps in atmospheric pressure air, nitrogen, CH4, SF6, xenon, krypton, argon and helium by two nanosecond-pulse generators. The rise time of generators were 0.3 (SLEP-150) and 1 ns (RADAN-220), and a full width at half maximum (FWHM) were 1 and 2 ns, respectively. The variables affecting the discharge characteristics, including the gap spacing d and applied pulse parameters, were investigated. With both generators supershort avalanches electron beam (SAEB) and X-rays were obtained. The characteristics of measured SAEB and X-rays on the all generators were studied. With Generator #1 in atmospheric pressure air it was obtained that FWHM of the total SAEB current pulse from the entire foil area is ̃ 100 ps and the amplitude of SAEB ̃ 100 A. With Generator #2 in all gases at the pressure of one atmosphere SAEB was registered.