An improved pulse-line accelerator-driven, intense current-density, and high-brightness pseudospark electron beam

A high-voltage (200 kV), high current-density, low-emittance (23/spl pi//spl middot/mm mrd), high-brightness (8/spl times/10/sup 10/ A/(mrd)/sup 2/) electron beam was generated in a pseudospark chamber filled with 15 Pa nitrogen and driven by a modified pulse line accelerator. The beam ejected with /spl les/1-mm diameter, 2.2-kA beam current, 400-ns pulse length, and about 20 cm propagation distance. Exposure of 10 shots on the same film produced a hole of 1.6-mm diameter at 7 cm downstream of the anode, and showed its good reproducibility. After 60 shots, it was observed that almost no destructive damage traces were left on the surfaces of the various electrodes and insulators of the pseudospark discharge chamber. It was experimentally found that the quality of the pseudospark electron beam remains very high, even at high voltages (of several hundred kilovolts), similar to low voltages, and is much better than the quality of the cold-cathode electron beams.