Realizing low-emittance lattice solutions with Complex Bends

A concept of new lattice element called "Complex Bend" is recently proposed at NSLS-II. Replacing the regular dipoles in the Double-Bend Achromat lattice by Complex Bends significantly reduces the beam emittance. The first attempt of lattice design for potential NSLS- II upgrade based on Complex Bend, is described. Compared with the current NSLS-II lattice, the new solution modifies only three of the six girders per cell. The linear optics has been matched keeping unchanged the lattice parameters at the straight sections, where the light-generating insertion devices are located. The Complex Bend gradient is limited by 250 T/m assuming possible use of permanent magnets. The lattice provides 65 pm emittance without damping wigglers, use of which results in further decrease of the emittance. (paper)