Study of abnormal vertical emittance growth in atf extraction line

M. Alabau Pons, A. Faus-Golfe, P. Bambade, J. Brossard, G. Le Meur, C. Rimbault, F. Touze, R. B. Appleby, A. Scarfe, D. Angal-Kalinin, J. Jones, M. Woodley, G. White, S. Kuroda, F. Zimmermann

    Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


    Since several years, the vertical beam emittance measured in the Extraction Line (EXT) of the Accelerator Test Facility (ATF) at KEK, that will transport the electron beam from the ATF Damping Ring (DR) to the future ATF2 Final Focus beam line, is significantly larger than the emittance measured in the DR itself, and there are indications that it grows rapidly with increasing beam intensity. This longstanding problem has motivated studies of possible sources of this anomalous emittance growth. One possible contribution is non-linear magnetic fields in the extraction region experimented by the beam while passing off-axis through magnets of the DR during the extraction process. In this paper, simulations of the emittance growth are presented and compared to observations. These simulations include the effects of predicted non-linear field errors in the shared DR magnets and orbit displacements from the reference orbit in the extraction region. Results of recent measurements using closed orbit bumps to probe the relation between the extraction trajectory and the anomalous emittance growth are also presented.
    Original languageEnglish
    Title of host publicationEPAC 2008 - Contributions to the Proceedings|EPAC - Contrib. Proc.
    PublisherEuropean Physical Society Accelerator Group (EPS-AG)
    Number of pages2
    Publication statusPublished - 2008
    Event11th European Particle Accelerator Conference, EPAC 2008 - Genoa
    Duration: 1 Jul 2008 → …


    Conference11th European Particle Accelerator Conference, EPAC 2008
    Period1/07/08 → …


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