Title :
Update of thermionic cathode progress
Author_Institution :
Hughes Aircraft Corp., Torrance, CA, USA
Abstract :
An update of progress in programs for improving thermionic cathode devices is presented. Innovative changes in the M-type impregnated cathode, specifically, the MM, CMM, MMM and transition metal emitters designed to preserve the initial cathode surface, are discussed. Also considered are low-cost high-brightness cathodes for high-definition television (HDTV), CPD types developed in the US and scandate types in Europe and Japan. High-temperature, high-brightness cathodes (LaB/sub 6/ and transition metal carbides) for lithographic or other unique applications are also discussed. Consideration is given to low-work-function cathodes (e.g. scandate) which can deliver 1-2 A/cm/sup 2/ at a much lower temperature than conventional impregnated cathodes and are capable of delivering pulsed currents in the range of 100 A/cm/sup 2/.<>
Keywords :
life testing; oxide coated cathodes; reviews; thermionic cathodes; CMM cathodes; CPD cathodes; HDTV; LaB/sub 6/; M-type impregnated cathode; MM cathodes; MMM cathodes; controlled porosity dispenser; high-brightness cathodes; high-definition television; low-work-function cathodes; mixed metal matrix cathodes; operational lifetime; pulsed currents; scandate cathodes; scandate types; thermionic cathode progress; transition metal carbides; transition metal cathodes; transition metal emitters; update current density; Brightness; Cathodes; Coordinate measuring machines; Current density; Europe; HDTV; Life testing; Microwave devices; NASA; Temperature;
Conference_Titel :
Electron Devices Meeting, 1991. IEDM '91. Technical Digest., International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-0243-5
DOI :
10.1109/IEDM.1991.235373
