Design and Construction of UVSOR-III

A 750 MeV low energy synchrotron light source, UVSOR, has been operational since 1983. To meet the strong demands for brighter light, an upgrade project was performed in 2003, in which the emittance was reduced from 160 nm-rad to 27 nm-rad and four 1.4-m long short straight sections were created. Thereafter, the light source was renamed UVSOR-II. During the ten years after this major upgrade, we have continued upgrading the light source. The top-up injection scheme was introduced and a new 4-m long straight section was created by moving the injection point. In 2012, the bending magnets were replaced with combined function ones to further reduce the emittance. These upgrades resulted in a light source, renamed UVSOR-III, that has an emittance of 17 nm-rad, is equipped with six undulators, and is fully operated in the top-up mode. The commissioning is in progress and user operation will start in August 2012.