Experimental Corroboration for a Ferrite-Core Model of High-Tc Bulk Superconductor Lenses (Supertrons)

Publisher Website
Google Scholar
Abstract
High-T c bulk superconductor lenses (Supertrons) for electron beams were operated over a temperature range from 65 to 130 K. The experimental results support a ferrite-core model of the lenses: Lenses for single short electron pulses are composed of fine grains of superconductors, as are ferrite cores. The lenses examined were Y-based 945°C and 750°C-sintered powder-pressed ones, an Y-based melt-processed one, a Bi-based 850°C-sintered powder-pressed one, and copper-block-made and copper-powder-pressed ones. Both the Bi-based and the Y-based 750°C-sintered lenses realized thinner electron beams ( ∼340 keV, ∼10 ns, ∼1.4 kA) with decreasing operation temperatures, especially below their T c's. The copper-powder pressed lens also worked better with falling temperatures, but was inferior to the Bi-based lens. These behaviors are understandable in view of the similarity in operation between ferrite cores and Supertrons.