  Three storage ring lattices have been designed as options for a future
upgrade of the Stanford synchrotron radiation lightsource (SSRL). The three
options differ in circumference and targeted future site, with one to be built
in the tunnel of the present SPEAR3 ring, one as a green field ring on the SLAC
campus, and the third in the tunnel of the decommissioned PEP-II ring. The
lattices are based on the newly proposed hybrid 6-bend achromat (H6BA) lattice
cells, which is ideal for pushing the photon beam brightness while achieving
excellent nonlinear dynamics performance. The transparent matching conditions
are enforced to minimize the negative impact of the loss of periodicity due to
insertion of various long straight sections. Numerical optimization is
performed to further improve the nonlinear dynamics. In addition to reaching
very low emittances, the lattices can accommodate traditional off-axis
injection and achieve beam lifetimes similar to or exceeding that of typical
third generation rings.
