Electron storage rings are the main sources of very bright photon beams. They are driving the majority of condensed matter material science and biology experiments in the world today. There has been remarkable progress in developing these light sources over the last few decades. Existing third generation light sources continue to upgrade their capabilities to reach higher quality photon beam while new light sources are being planned and designed with ever improving performance. Idea of ultimate storage rings (USR) has recently been proposed to have beam emittance down to few tens of pico-meters, reaching diffractive limit of hard X-ray. This theses work is dedicated to designing a storage ring with ultra-small beam emittance using n-bend achromat (n-BA) structure.

For ultimate storage rings, large natural chromaticities require strong sextupoles to correct. Strong non-linear effect requires the study of dynamic aperture (DA). We calculate and optimize the DA to achieve a 1.5 mm by 1.5 mm aperture size. Other instabilities such as intra-beam scattering (IBS) and microwave instabilities (MI) are evaluated self-consistently. Possible free electron laser (FEL) scheme has been proposed to facilitate the implementation of this ultimate storage ring design.