Report / ACCDT / DR EDMS D*1009305 ILC-REPORT-2012-038

The CESR Test Accelerator Electron Cloud Research Program Phase I Report

Palmer, M. A. ; Billing M. G. ; Dugan, G. F. ; Furman, M. A ; Rubin, D. L.

Abstract: The build-up of the electron cloud (EC) in the positron damping ring (DR) of the International Linear Collider (ILC) is one of the principal risk factors for the overall physics performance of the accelerator. In positron storage and damping rings, electrons are produced in the accelerator vacuum chambers through photoemission and secondary emission. Interaction between the resulting EC and the beam can lead to single- and multi-bunch instabilities in the beam. The onset of a single-bunch head-tail instability, which cannot in general be controlled by a conventional feedback system, will lead to emittance growth in the beam. For the ILC DR, which targets a geometric vertical emittance of 2 pm-rad, we must ensure that the machine can be operated safely below this instability threshold. Below the threshold for the onset of single-bunch instabilities, sub-threshold emittance dilution may still occur through the interaction of the beam with the nonlinear fields of the EC. With the ultra low emittance target of the ILC DR, there is little margin for such emittance diluting effects. Hence this area was identified as one requiring further R&D in order to complete the ILC technical design.

Keyword(s): electron-cloud, cesrta
Note: Draft - November 26, 2012

The record appears in these collections:
Accelerator Design & Technology > ILC Beamline Areas > Damping Ring (DR)
Documentation > Publications & Notes > Reports
Accelerator Design & Technology > ILC General

 

 Record created 2012-12-20, last modified 2012-12-21


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