Copper Alloying to Improve Barium Electron Beam Source
Original Publication Date: 1988-Sep-01
Included in the Prior Art Database: 2005-Feb-15
A technique is described whereby copper alloying is used to improve the stability and the resistance to oxidation of barium electron beam source materials. Barium, in addition to copper, is typically used in some high temperature oxide superconductors, such as Y1Ba2Cu306. It is a highly reactive metal, oxidizes rapidly and reacts with water or moisture to form BaO plus H2 and has a very high vapor pressure. These characteristics make controlled beam evaporation of Ba, as used in high Tc films, extremely difficult and results in two specific problems such as: - High vapor pressure of Ba (6.8 x 10-3 Torr), at its melting point of 710oC, results in high evaporation rates (greater than 2 A/sec.). The high Ba rate must be compensated by a proportional increase in other sources.