Compact coaxial diode electron beam system: Carbon cathodes and anode fabrication techniques

A coaxial electron beam generator has been developed which produces current densities of 1-3 A cm^-2 at the anode foil, is compact (Marx ∼0.2 m³) and yet utilizes an anode of 50 cm length and 250 cm³ volume. Carbon cathodes (carbon fibers and graphite felt) tested on this system have been found to be superior to metal foil blades for current risetime and peak current. Techniques for readily fabricating cylindrical anodes of arbitrarily large volume and length are also described. The use of this system in exciting Ar/5% N₂ gas mixtures has resulted in intense laser emission (E_max∼2 mJ) on the (0,3) transition of the N₂ (C→B) band at 405.9 nm. Also, coaxial photolytic experiments involving XeF₂ and a buffer gas have yielded strong XeF emission on the B→X (ultraviolet) and C→A (blue-green) bands.