Studies on Transverse Resonance Island Buckets in third and fourth generation synchrotron light sources

Abstract A Transverse Resonance Island Bucket optics has a betatron tune close to a resonance, such that the particle motion is governed by non-linear terms in the equation of motion. This results in additional stable fixed points in transverse phase-space, which can be populated with a single RF-bunch filling pattern. Thus, these optics have the potential of providing pseudo single-bunch operation, i.e. allows some beamlines to receive light pulses at the revolutionary frequency while the remaining beamlines continue to receive pulses with a frequency set by the ring RF. By blocking either the synchrotron radiation from the standard orbit or secondary orbit each beamline can individually choose whether they want multi- or single-bunch synchrotron radiation. Transverse Resonance Island Bucket optics were achieved in both MAX IV storage rings. In particular, the optics of the 1.5 GeV ring has been characterized both theoretically and experimentally, and we show that TRIBs are achieved in a lattice without any octupolar elements. Furthermore, a feasibility study was performed which indicates that the beamlines of the 1.5 GeV ring could make use of the synchrotron radiation from the island orbit while blocking the standard orbit radiation.