The Electron Storage Ring
The 7-GeV electrons are injected into the 1104-m-circumference storage ring, a circle of more than 1,000 electromagnets and associated equipment, located in a radiation-proof concrete enclosure inside the experiment hall, which is large enough to encircle Chicago's U.S. Cellular Field. A powerful electromagnetic field focuses the electrons into a narrow beam that is bent on a circular path as it orbits within aluminum-alloy vacuum chambers running through the centers of the electromagnets.
The sequencing, or lattice, of magnets in the APS storage ring produces a beam of very small size and low angular divergence, qualities prized by users of synchrotron light sources. The lattice also results in 40 straight sections, or sectors, in the storage ring. Five sectors are used for beam injection and rf equipment. The remaining 35 can be instrumented to provide the sources of the brightest x radiation in the Western Hemisphere.