Fast- and super-fast-warm-up cathodes using novel APG/APBN heaters

Author

Cattelino, M.J. ; Miram, G.V. ; Smith, Bernard

Author_Institution

Varian Associates Inc., Palo Alto, CA, USA

Volume

38

Issue

10

fYear

1991

fDate

10/1/1991 12:00:00 AM

Firstpage

2239

Lastpage

2243

Abstract

A fast-warm-up heater/cathode approach for microwave tubes is described. Anisotropic pyrolytic graphite (APG) deposited onto anisotropic pyrolytic boron nitride (APBN) was used to fabricate heater wafers. Both planar and spherical heaters can be produced. APG/APBN characteristics are discussed along with methods for heater fabrication. Measured fast-warm-up thermal cycling data are presented for 4 to 60 mm cathode diameters. Fast warm-up times of 1-2 s for 4.0-6.4-mm-diameter cathodes and less than 20 s for 60-mm-diameter cathodes were demonstrated with highly reliable thermal cycling performance

Keywords

microwave tubes; thermionic cathodes; 1 to 20 s; 4 to 60 mm; APG/APBN heaters; C-BN; anisotropic pyrolytic graphite; anisotropic pyrolytic nitride; cathodes; fast-warm-up thermal cycling data; heater fabrication; heater wafers; microwave tubes; spherical heaters; super-fast-warm-up; Anisotropic magnetoresistance; Boron; Cathodes; Coatings; Electromagnetic heating; Fabrication; Impedance; Magnetic fields; Thermal conductivity; Wire;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.88505

Filename

88505