Nanosecond generation of intense electron currents with high-Tc superconducting rings

Pulse compression of intense electron beams similar to340 keV, similar to1 kA, and similar to10 ns) was observed for the following two superconducting ring lenses (supertrons): an already sintered 1 mum sized powder-pressed Bi(2223)-based ring lens and a double-layered lens having an outer melt-processed Y-based ring. The outer- and innermost diameters of the lenses were 22 and 16 mm, respectively, with a total axial length of 55 mm including a funnel-type inlet. The powder-pressed lens compressed the electron pulses to similar to5 ns in duration at 70 K, whereas the double-layered lens provided similar to3.7 ns pulses. The durations were both longer than those (similar to1.4-3.0 ns) for previous double-layered lenses in which the inner rings were made from sintered Bi(2223)-based materials. These results are explained by a ferrite-core model for supertrons. (C) 2002 Elsevier Science B.V. All rights reserved.