  We developed a low emittance electron storage ring with large 6D dynamic
aperture. Contrary to the traditional approach using strong focusing magnetic
cells with optimized (and large) horizontal phase advance, which yields huge
natural chromaticity, we employed a relatively weak focusing lattice with low
chromaticity per cell and, consequently, wide on- and off-momentum dynamic
aperture. Inevitable for weak focusing emittance growth, we compensated by
slicing the lattice into many short, with small bending angle, elementary
periodic cells. To reduce the size, we superimposed focusing gradient and
chromaticity compensating sextupole components over the dipole field utilizing
superconducting magnets based on the Canted Cosine Theta (CCT) winding
technology. The result is a model lattice with 50 pm horizontal emittance at 3
GeV beam energy, with 400-500 m circumference and large 6D aperture.
