Abstract:
Modern synchrotron light sources are competing to increase x-ray brightness and, eventually, approach the diffraction limit, which sets the goal of lattice emittance. All recent synchrotron facility upgrades follow the MultiBend Achromat approach by arranging small horizontal beta function and dispersion inside discrete bending dipoles. In this presentation we will discuss a concept of a lattice element that we call “Complex Bend,” which is a sequence of dipole poles interleaved with strong alternate focusing so as to maintain the beta function and dispersion oscillating at low values. Comprising the ring lattice with Complex Bends, instead of regular dipoles, will minimize the H-function and reduce horizontal emittance while localizing bending to a small fraction of the storage ring circumference, which should provide more space for insertion devices.

We present the details of the Complex Bend (versions I, II and III), considerations regarding the choice of optimal parameters, and thoughts for its practical realization. We will discuss some work on the ring lattices with Complex Bend elements for NSLS-II upgrade.