Wakefield Calculations for Radiation Stopper 1 (RST1)

Limborg-Deprey, C.

SLAC National Accelerator Laboratory

关键词: Light Sources;    Energy Absorption;    43 Particle Accelerators;    Beam Bunching;    Electron Beam Injection;   

DOI  :  10.2172/1000393
RP-ID  :  SLAC-TN-10-083
RP-ID  :  AC02-76SF00515
RP-ID  :  1000393

美国|英语

来源: UNT Digital Library

【 摘 要 】

The main result of this note is that no wakefield mitigation is required for the Radiation Stopper (RST1) in the LCLS injector. The RST1 geometry is not symmetric in the vertical direction, and we derive a slight modification to the diffraction model wake for a cylindrically symmetric (2D) cavity that can be used for this problem. Performing a full 3D MAFIA calculation for the nominal 1 mm (rms) long bunch, we show that the modified diffraction model well describes the wakefields generated in RST1. The results imply an on-axis emittance growth of 0.0075%, well below the 0.5% tolerance threshold. To reach the 0.5% threshold the beam would need to be mis-steered by a large amount - 7 mm - from the axis. One reason that the effect is small is that the beta functions at the RST1 are small.