Beschleunigerphysik

The proton cycle in the SIS100 synchrotron is designed to deliver single bunches with $2\times10^{13}$ particles at 29 GeV. During the cycle beam dynamics near transition energy have to be analyzed to avoid a significant emittance blow-up. [...]

The multipass regenerative multibunch beam breakup instability is specific to recirculating linacs (linear accelerators) and energy recovery linacs operating in continuous wave mode where particle bunches pass multiple times through the same superconducting RF cavities with extremely high quality factor. Parasitic electromagnetic modes excited in the cavities can affect bunch dynamics in such a way, that on its subsequent passes it excites the modes further and a positive feedback loop is formed. [...]