New storage ring lattice for the duke fel wiggler switchyard system
The Duke storage ring is a dedicated driver for the OK- 4 FEL and OK-5 FEL, and forthe state-of-the-art Compton gamma-ray source, High Intensity Gamma-Ray Source (HIGS). Toproduce FEL lasing below 190 nm and gammaray beams above 100 MeV, the FEL system needs tobe upgraded to increase the FEL gain by adding two more helical OK-5 wigglers to form afour-wiggler FEL. To preserve the linear polarization capability of the gamma-ray beamproduced by the planar OK-4 FEL, a wiggler switchyard system is under development whichwill enable the switch between two planar OK-4 wigglers and two helical OK-5 wigglers inthe middle of the FEL straight. In this work, we present the new magnetic lattice designedfor the operation of the wiggler switchyard system. This new lattice is developed withgreat flexibility for the operation with different numbers of FEL wigglers, variablebetatron tunes, and adjustable electron beam sizes at the collision point for the HIGS. Inaddition, the new lattice is developed for the operation in a wide range of energies, from240 MeV to 1.2 GeV, with proper nonlinear dynamics compensations in order to realize alarge dynamic aperture. Copyright © 2012 by IEEE.