Impedance Characterization and Collective Effects in the MAX IV 3 GeV Ring

Galina Skripka , Åke Andersson , Francis Cullinan (1) , Ryutaro Nagaoka (1) , Pedro Tavares

1 SSOLEIL - Synchrotron SOLEIL

Collective instabilities in the MAX IV 3 GeV storage ring are enhanced by the combination of high beam current, ultralow emittance and small vacuum chamber aperture. To mitigate instabilities by Landau damping and improve lifetime three passive harmonic cavities are installed to introduce synchrotron tune spread and bunch lengthening respectively. We present the results of studies of collective effects driven by the machine impedance. Bunch lengthening and detuning were measured to characterize the effective impedance and estimate the effect of the harmonic cavity potential. Investigations of collective effects as a function of parameters such as beam current and chromaticity are discussed.

Mots clés: ion; impedance; synchrotron; feedback; experiment

Domaines: Physique des accélérateurs [physics.acc-ph]

Galina Skripka, Åke Andersson, Francis Cullinan, Ryutaro Nagaoka, Pedro Tavares. Impedance Characterization and Collective Effects in the MAX IV 3 GeV Ring. 2nd North American Particle Accelerator Conference, Oct 2016, Chicago, United States. pp.WEA3CO04, ⟨10.18429/JACoW-NAPAC2016-WEA3CO04⟩. ⟨hal-01645829⟩