• M.G. Billing, M.J. Forster, H.A. Williams
  CLASSE, Ithaca, New York

This paper describes the results of measurements compared with the analysis of errors for a method of determining accelerator Twiss and coupling parameters from the singular value decomposition of beam position monitor data, taken on a turn-by-turn basis for a storage ring in fully coupled transverse beam coordinates. Using the transversely coupled-coordinate formalism described by Billing et al*, the measurement technique expands on the work of Wang et al**, which describes the SVD of the same data under the assumptions of no transverse coupling of the beam parameters. This particular method of data analysis requires a set of BPM measurements, taken when the beam is resonantly excited in each of its two dipole, betatron normal-modes of oscillation

*M. Billing, et al, to be published in Phys. Rev. S T – Accel Beams
**C. Wang, et al, Phys. Rev. S T – Accel Beams 6, 104001 (2003)

• M.G. Billing, H.A. Williams
  CLASSE, Ithaca, New York

Wake fields arising from the discontinuities in the vacuum chamber produce energy spread. In an energy recovery linac (ERL), a spent beam is decelerated before it is dumped in order to use its energy for the acceleration of new beam. While the energy spread accumulated from wakes before deceleration does not increase during deceleration, it becomes more important relative to the beam's decreasing energy. Therefore, in an ERL, wakes can produce very significant energy spread in the beam as it is decelerated to the energy of the beam dump so that beam transport to the dump may become impractical. This effect can place a limit either on the maximum charge per bunch or on the wake field-budget for the ERL. As an example of these wake field effects, this paper discusses their impact for the present design of the Cornell ERL and estimates the effects for typical vacuum chamber components being considered.

• M.A. Palmer, J.P. Alexander, M.G. Billing, J.R. Calvey, S.S. Chapman, G.W. Codner, C.J. Conolly, J.A. Crittenden, J. Dobbins, G. Dugan, E. Fontes, M.J. Forster, R.E. Gallagher, S.W. Gray, S. Greenwald, D.L. Hartill, W.H. Hopkins, J. Kandaswamy, D.L. Kreinick, Y. Li, X. Liu, J.A. Livezey, A. Lyndaker, V. Medjidzade, R.E. Meller, S.B. Peck, D.P. Peterson, M.C. Rendina, P. Revesz, D.H. Rice, N.T. Rider, D. L. Rubin, D. Sagan, J.J. Savino, R.D. Seeley, J.W. Sexton, J.P. Shanks, J.P. Sikora, K.W. Smolenski, C.R. Strohman, A.B. Temnykh, M. Tigner, S. Vishniakou, W.S. Whitney, T. Wilksen, H.A. Williams
  CLASSE, Ithaca, New York
• J.M. Byrd, C.M. Celata, J.N. Corlett, S. De Santis, M.A. Furman, A. Jackson, R. Kraft, D.V. Munson, G. Penn, D.W. Plate, A.W. Rawlins, M. Venturini, M.S. Zisman
  LBNL, Berkeley, California
• J.W. Flanagan, P. Jain, K. Kanazawa, K. Ohmi, H. Sakai, K. Shibata, Y. Suetsugu
  KEK, Ibaraki
• K.C. Harkay
  ANL, Argonne
• Y. He, M.C. Ross, C.-Y. Tan, R.M. Zwaska
  Fermilab, Batavia
• R. Holtzapple
  CalPoly, San Luis Obispo, CA
• J.K. Jones
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• D. Kharakh, M.T.F. Pivi, L. Wang
  SLAC, Menlo Park, California
• E.N. Smith
  Cornell University, Ithaca, New York
• A. Wolski
  Cockcroft Institute, Warrington, Cheshire

Funding: Support provided by the US National Science Foundation, the US Department of Energy, and the Japan/US Cooperation Program.

In March of 2008, the Cornell Electron Storage Ring (CESR) concluded twenty eight years of colliding beam operations for the CLEO high energy physics experiment. We have reconfigured CESR as an ultra low emittance damping ring for use as a test accelerator (CesrTA) for International Linear Collider (ILC) damping ring R&D. The primary goals of the CesrTA program are to achieve a beam emittance approaching that of the ILC Damping Rings with a positron beam, to investigate the interaction of the electron cloud with both low emittance positron and electron beams, to explore methods to suppress the electron cloud, and to develop suitable advanced instrumentation required for these experimental studies (in particular a fast x-ray beam size monitor capable of single pass measurements of individual bunches). We report on progress with the CESR conversion activities, the status and schedule for the experimental program, and the first experimental results that have been obtained.

Slides