Measuring Duke storage ring lattice using tune based technique
The Duke electron storage ring is a dedicated driver for oscillator Free-Electron Lasers (FELs). A 34 m long straight section of the storage ring is used to host up to four FEL wigglers in several different configurations. A total of six wigglers, two planar OK-4 wigglers and four helical OK-5 wigglers, are available for FEL research. The storage ring magnetic lattice has to be designed with great flexibility to enable the storage ring operation with different FEL wigglers, at various wiggler settings, and for different electron beam energies. Since 2012, the storage ring has demonstrated all designed characteristics in terms of lattice flexibility and tuning. This work is aimed at gaining better understanding of the real storage ring lattice by performing a series of measurements of the beta-functions along the storage ring. Unlike the LOCO technique, the β-functions in the quadrupoles are directly measured with good accuracy using a tune measurement system. We will describe our experimental design and techniques, and measurement procedures. We will also report our preliminary results for the lattice characterization.
