Beam-breakup calculations for the DARHT accelerator

Paul Allison, Michael J. Burns, George J Caporaso, Art G. Cole

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


An induction line that will accelerate a 4-MeV, 3-kA beam of electrons to 16- to 20-MeV in 64 gaps is modeled. To suppress beam-breakup (BBU) instabilities induced by excitation of RF deflecting modes, the growth factor Γ must be kept sufficiently small (e.g. <3). On prototype DARHT cavities, RF measurements have shown that the normally degenerate TM modes are split in frequency by the asymmetry that the two pulsed-power drive rods present to the cavity. If half the cavities had vertical and half had horizontal drive-rod orientations, the effective number of gaps would be reduced by half if there were no coupling between the modes by the solenoid focusing and if the split modes had no overlap. The LLNL (Lawrence Livermore National Laboratory) code BREAKUP was used to study BBU growth for drive rod alternation patterns of blocks of 1, 2, 4, 8, 16, 24, 32, or 64 (no alternation) for both constant and alternating polarity solenoids.

Original languageEnglish (US)
Title of host publicationConference Record of the 1991 IEEE Particle Accelerator Conference
Place of PublicationPiscataway, NJ, United States
PublisherPubl by IEEE
Number of pages3
ISBN (Print)0780301358
StatePublished - 1992
Externally publishedYes
EventConference Record of 1991 IEEE Particle Accelerator Conference Part 5 (of 5) - San Francisco, CA, USA
Duration: May 6 1991May 9 1991


OtherConference Record of 1991 IEEE Particle Accelerator Conference Part 5 (of 5)
CitySan Francisco, CA, USA

ASJC Scopus subject areas

  • Engineering(all)


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