Suppression of the transit -time instability in large-area electron beam diodes

Experiment, theory, and simulation have shown that large-area electron-beam diodes are susceptible to the transit-time instability. The instability modulates the electron beam spatially and temporally, producing a wide spread in electron energy and momentum distributions. The result is gross ineffic...

Full description

Saved in:
Bibliographic Details
Published in2002 14th International Conference on High-Power Particle Beams (BEAMS) Vol. 1; pp. 231 - 234
Main Authors Myers, Matthew C., Friedman, Moshe, Swanekamp, Stephen B., Chan, Lop-Yung, Ludeking, Larry, Sethian, John D.
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.06.2002
Subjects
Online AccessGet full text

Cover

Loading…
More Information
Summary:Experiment, theory, and simulation have shown that large-area electron-beam diodes are susceptible to the transit-time instability. The instability modulates the electron beam spatially and temporally, producing a wide spread in electron energy and momentum distributions. The result is gross inefficiency in beam generation and propagation. Simulations indicate that a periodic, slotted cathode structure that is loaded with resistive elements may be used to eliminate the instability. Such a cathode has been fielded on one of the two opposing 60 cm × 200 cm diodes on the NIKE KrF laser at the Naval Research Laboratory. These diodes typically deliver 600 kV, 500 kA, 250 ns electron beams to the laser cell in an external magnetic field of 0.2 T. We conclude that the slotted cathode suppressed the transit-time instability such that the RF power was reduced by a factor of 9 and that electron transmission efficiency into the laser gas was improved by more than 50%.
ISBN:9780735401075
0735401071
DOI:10.1063/1.1530842