Preliminary Expected Performance Characteristics of an APS Multi-Bend Achromat Lattice

The Advanced Photon Source is the brightest storage ring synchrotron radiation source in the western hemisphere. It is presently in the midst of an upgrade to deliver even higher performance and powerful new capabilities for scientific research using hard x-ray techniques. Recently, it has become accepted that a new avenue for creating high brightness x-ray beams is opening up, based on technology that enables the use of multi-bend achromat (MBA) magnet lattices in the storage ring. In July, a report by the Basic Energy Sciences Advisory Committee (BESAC) [1] recommended considering the incorporation of this new technology to enhance research facilities such as the APS. Hence, the APS Upgrade is exploring how the incorporation of an MBA lattice into the on-going project can optimize the scientific capabilities. To facilitate discussion of the scientific impact and design optimization of such a lattice, this document describes the expected performance characteristics calculated for an initial “straw-man” design. Since the design is still being developed, these characteristics may change in the future as they are optimized with community input. A primary benefit of the MBA lattice is to dramatically increase x-ray brightness, which is achieved by implementing four improvements, listed here in order of importance: