A challenge in realizing a steady-state microbunching (SSMB) light source is achieving a high average current from a stored beam with a peak current low enough to avoid collective effects that spoil the longitudinal phase space. We plan to investigate resolving this challenge by combining recent advances in isochronous transport and induction cells. The recently commissioned SLS-2 upgrade uses an anti-bend arc cell to control dispersion and reduce emittance. We use this anti-bend design to yield an arc whose R56 can be adjustable to near-zero on a per-arc basis. This fine control of momentum compaction allows for better mitigation of effects that spoil the longitudinal phase space. A consequence of RF technology, which most ring-based light sources use, is that high average current can only be achieved by pushing peak current, as only 1-2% of the circumference actually stores current. High peak current drives other design considerations which result in a fast churning of the longitudinal phase space. A ring with low peak current to avoid this churning has an average current too low to make a useful SSMB light source. Induction cells with a reset time of ~10 ns have recently been developed for cinematographic radiography. An induction cell could allow over 95% of the ring to store current, yielding a high average current and low peak current. Here we outline an investigation to explore the beam dynamics and technology of such an isochronous induction cell storage ring.
Ehrlichman et al. (Thu,) studied this question.