Study of Low beta-y Straight Section in SPEAR 3

The SPEAR 3 light source has two 7.6 m straight sections one of which is available for new insertion devices (ID). By reducing the vertical {beta}{sub y} function at the center of the straight from 9.8 m to 1.5 m, the beam size can be decreased from 44 {micro}m to 17 {micro}m to reduce the ID gap, but the ID length may be limited by the increased {beta}{sub y} variation in the ID. Alternatively, a ''double waist'' optics with two symmetric low {beta}{sub y} locations and a chicane may be considered to implement two IDs. In this paper, we discuss the low {beta}{sub y} optics, effects on the beam dynamic aperture, and the ID parameters needed to maximize photon flux density and brightness while maintaining electron beam lifetime.