NSLS-II is planning an upgrade to an ultra-low emittance storage ring using a novel lattice concept, the complex bend, composed of combined-function magnets. To evaluate technical challenges and study beam dynamics with complex bend, two bending magnets of existing NSLS-II bare lattice are proposed to be replaced with complex bends, introducing lattice asymmetry. To study the impact of asymmetry on NSLS-II bare lattice, an asymmetric lattice is developed by adjusting quadrupole triplets in the Cell 8 long straight section. This paper presents the modified linear optics, optimization of nonlinear dynamics, and a comparison with the nominal bare lattice. The optimized asymmetric bare lattice is also experimentally measured in the machine, and dynamic aperture measurements are reported.
Song et al. (Thu,) studied this question.