Beam-cavity interaction physics for mildly relativistic, intense-beam klystron amplifiers

Author

Carlsten, B.E. ; Faehl, R.J. ; Fazio, M.V. ; Haynes, W.B. ; Ryne, R.D. ; Stringfield, R.M.

Author_Institution

Los Alamos Nat. Lab., NM, USA

Volume

22

Issue

5

fYear

1994

fDate

10/1/1994 12:00:00 AM

Firstpage

730

Lastpage

739

Abstract

We examine beam-cavity interaction physics relevant to mildly relativistic, intense-beam klystron amplifiers. This is an interesting but difficult regime of operation, because of the combination of high beam current and low voltage. The advantage of this regime is that it is relatively easy to access high beam powers (and potentially high microwave output powers) at relatively low beam energy. We calculate the effect of the extremely high beam loading in the input and idler cavities. The output cavity´s shunt impedance must match the low beam impedance in order to prevent high output gap voltages that will reflect electrons back upstream. This leads to very low cavity Q factors (<10). We derive expressions for mode purity for such low-Q cavities and show that acceptable cavities can be designed

Keywords

Q-factor; cavity resonators; electron beams; impedance matching; klystrons; microwave generation; microwave power amplifiers; relativistic electron beam tubes; beam-cavity interaction physics; cavity Q factors; high beam current; idler cavities; input cavities; intense-beam klystron amplifiers; low voltage operation; mildly relativistic tubes; mode purity; shunt impedance; Electron beams; Impedance; Klystrons; Low voltage; Microwave circuits; Physics; Power amplifiers; Power generation; US Department of Energy; Weapons;

fLanguage

English

Journal_Title

Plasma Science, IEEE Transactions on

Publisher

ieee

ISSN

0093-3813

Type

jour

DOI

10.1109/27.338289

Filename

338289