Linearized Wigglers for Damping Rings

75779-Both U.S. and European scientists are evaluating the use of permanent magnet wigglers in the damping rings of linear colliders to reduce vertical emittance. These wigglers pose unique analysis, design, and engineering challenges. The first challenge is to control the nonlinear dynamics caused by the magnetic field transverse roll-off, which can disrupt beam quality and damage the wiggler. The second challenge is build-up of an electron cloud, which can reduce equilibrium emittance and impose an upper limit on the current. Phase I will design a ¿linearized¿ wiggler with greatly reduced transverse roll-off and nonlinear field effects. Two approaches will be individually analyzed using magnetic field analysis software, guided by previous experience with controlling transverse roll-off and higher-order fields. The approaches will be then evaluated together as an integrated system. Phase II will perform design verification tests on a half-period prototype to validate the Phase I approach. Also, a database will be established as a guide for end users of these wigglers. Commercial Applications and Other Benefits as described by the awardee: Besides addressing the problem of transverse roll-off and nonlinear field effects in colliders, the linearized wiggler also should be less expensive to build. The reduced cost should directly benefit other wiggler applications, such as in synchrotron storage rings, industrial processing, medicine, and academia.