CERN Accelerating science

Article
Report number	SLAC-PUB-11227
Title	Resistive Wall Wakefield in the LCLS Undulator
Author(s)	Bane, Karl Leopold Freitag ; Stupakov, Gennady
Affiliation	(SLAC)
Publication	2005
Imprint	2005
Number of pages	4
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.3390
Abstract	In the Linac Coherent Light Source (LCLS), a short, intense bunch (rms length 20 microns, bunch charge 1 nC) will pass through a small, long undulator beam pipe (radius 2.5 mm, length 130 m). The wakefields in the undulator, particularly the resistive wall wake of the beam pipe, will induce an energy variation along the bunch, a variation that needs to be kept to within a few times the Pierce parameter for all beam particles to continue to lase. Earlier calculations included the short-range resistive wall wake, but did not include the frequency dependence of conductivity (ac conductivity) of the beam pipe walls. We show that for copper and for the LCLS bunch structure, including the ac conductivity results in a very large effect. We show that the effect can be ameliorated by choosing aluminum and also by taking a flat, rather than round, beam pipe chamber (if the vertical aperture is fixed). The effect of the (high frequency) anomalous skin effect is also considered.

Corresponding record in: Inspire