Spectrum of fast electrons in subnanosecond breakdown of air-filled diodes at atmospheric pressure

The spectra of electron beams produced in air-filled diodes at atmospheric pressure were studied. The feasibility of correct reconstruction of the electron beam spectrum from an experimental dependence of its attenuation factor in foils of different thickness was demonstrated. The electron energy distributions were calculated on minimum a priori assumptions by regularization of an ill-posed problem (a Fredholm integral equation. The spectra of a subnanosecond electron beam generated in the gas gap during the voltage pulse rise time were reconstructed and analyzed. A time-of-flight spectrometer study and reconstruction of the spectrum from the data on e-beam attenuation confirmed the fact that groups of electrons with two-three characteristic energies can be generated in gas-filled diodes. In experiments, electrons of energy greater than that corresponding to the nominal voltage amplitude across the gap were detected.