Specific features of magnet design for the Duke FEL storage ring
The 1 GeV Duke FEL storage ring is dedicated to drive UV and VUV free electron laser devices. The high brightness and low emittance electron beams needed for these devices demand high performance and tight tolerances on the storage ring magnet lattice. Tight tolerances include close spacing of magnetic elements. We show how combined function magnets are used to eliminate discrete elements and odd shaped end pieces which cause magnetic coupling, saturation and severe undesirable field nonlinearities. Using this scheme we are able to achieve desirable ring dynamic aperture with only minor modification of existing hardware. Also included is a discussion of a non-standard septum magnet with stray field compensation which will be employed by this storage ring. The design, testing procedures, and preliminary results are outlined for this magnet.<<ETX>>