PAC09 - List of Authors (Sheppard, J.)

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Sheppard, J.

Paper	Title	Page
WE6PFP068	Emittance Evolution of the Drive Electron Beam in a Helical Undulator for ILC Positron Source	2656
	W. Gai, M. Borland, K.-J. Kim, W. Liu, A. Xiao ANL, Argonne J. Sheppard SLAC, Menlo Park, California
	Funding: This work was supported by the US Department of Energy Office of Science under Contract No. DE-AC02-06CH11357. The effect of ILC positron source’s helical undulator to the drive electron beam is of great interest. People have been looking into the effect of wakefield, quad misalignment and also the effect of radiation. In this paper we’ll report an emittance damping effect of the ILC positron source undulator to the drive electron beam and our QUAD-BPM error simulation results. For 100m RDR undulator, the emittance of drive electron beam will be damped down by about 1% instead of growing as the damping is stronger than quantum excitation for this RDR undulator with the RDR drive electron beam. Quad-BPM misalignment simulations show that a 20um rms misalignment error in a 250m long undulator beamline can cause about 5% emittance growth in drive electron beam. Taking into consider the damping effect of undulator, the net emittance growth will be smaller.

Paper

Title

Page

WE6PFP068

Emittance Evolution of the Drive Electron Beam in a Helical Undulator for ILC Positron Source

2656

W. Gai, M. Borland, K.-J. Kim, W. Liu, A. Xiao
ANL, Argonne
J. Sheppard
SLAC, Menlo Park, California

Funding: This work was supported by the US Department of Energy Office of Science under Contract No. DE-AC02-06CH11357.

The effect of ILC positron source’s helical undulator to the drive electron beam is of great interest. People have been looking into the effect of wakefield, quad misalignment and also the effect of radiation. In this paper we’ll report an emittance damping effect of the ILC positron source undulator to the drive electron beam and our QUAD-BPM error simulation results. For 100m RDR undulator, the emittance of drive electron beam will be damped down by about 1% instead of growing as the damping is stronger than quantum excitation for this RDR undulator with the RDR drive electron beam. Quad-BPM misalignment simulations show that a 20um rms misalignment error in a 250m long undulator beamline can cause about 5% emittance growth in drive electron beam. Taking into consider the damping effect of undulator, the net emittance growth will be smaller.