Minimized Emittance Growth with Elliptical Beam Pipes in FEL (Free-Electron-Laser).

摘要

Wakefield effects can cause emittance growth in free-electron-laser systems and reduce free-electron-laser gain. This paper explains that, by using beam pipes with elliptical cross sections, discontinuities can be allowed along a beam pipe without introducing wakefields. To use a beam pipe with an elliptical cross section, wakefield-less transitions between beam pipes with circular and elliptical cross sections are also needed. A concept to achieve such a transition is discussed. 4 refs., 7 figs.