Electron cloud in the wigglers of the position dampling ring of the international linear collider

Abstract

The ILC positron damping ring comprises hundreds of meters of wiggler sections, where many more photons than in the arcs are emitted, and with the smallest beampipe aperture of the ring. A significant electron-cloud density can therefore be accumulated via photo-emission and via beam-induced multipacting. In field-free regions the electron-cloud build up may be suppressed by adding weak solenoid fields, but the electron cloud remaining in the wigglers as well as in the arc dipole magnets can still drive single-bunch and multi-bunch beam instabilities. This paper studies the electron-cloud formation in an ILC wiggler section for various scenarios, as well as its character, and possible mitigation schemes.

The conversion of CESR to operate as the test accelerator, CesrTA, Part 4: superconducting wiggler diagnostics

“…• The grooved RFA SCW assembly was coated with TiN and then reinstalled in the L0 EC experimental region in January 2011. Simulations [6] predicted distinct longitudinal and transverse EC density distributions in wiggler beam pipes. The design goal of the wiggler RFA beam pipe is to place RFAs at strategic longitudinal locations in the wiggler magnetic field to measure the corresponding transverse EC density distributions.…”