Characterization of the Double-Double Bend Achromat Lattice Modification to the Diamond Light Source Storage Ring

The Diamond storage ring has recently been modified by replacing one of the original double bend achromat (DBA) cells with a double-DBA (DDBA) cell. The new cell marks a fundamental break to the machine symmetry, and the final engineered solution shares many design features in common with modern multi-bend achromat cells. In this paper we review the impact that the modification has had on the linear and nonlinear optics, collective effects, and overall performance. Where appropriate, comparison to model predictions are also made.