Lattice design for the Diamond-II light source storage ring

To satisfy user demands for a high-brightness, high-capacity synchrotron light source, a novel multibend achromat (MBA) lattice structure has been developed for the Diamond-II storage ring upgrade. This lattice combines the high-dispersion locations characteristic of hybrid MBA lattices with newly introduced midcell straight sections to allow extra insertion devices to be installed. The resulting structure is named the modified hybrid six bend achromat (MH6BA) lattice. When adapted to fit in the existing 560.6 m Diamond storage ring tunnel, it reaches a natural emittance of 162 pm rad at 3.5 GeV. The characteristics of the MH6BA lattice, the methodology used to optimize the linear and nonlinear beam dynamics, and the lattice performance in a range of conditions are discussed.