Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities

Conference · Mon Jul 07 04:00:00 EDT 2008

OSTI ID:934752

Bane, K L.F.; Adolphsen, C; Li, Z; Dohlus, M; Zagorodnov, I; Gonin, I; Lunin, A; Solyak, N; Yakovlev, V; Gjonaj, E; Weiland, T

In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 934752
• Report Number(s): SLAC-PUB-13276
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
ASYMMETRY
Accelerators
ACCPHY
BEAM EMITTANCE
CAVITIES
LINEAR ACCELERATORS
LINEAR COLLIDERS
PERFORMANCE