• Y. Li, X. Liu, V. Medjidzade, M.A. Palmer, D.H. Rice, D. L. Rubin, J.J. Savino
  CLASSE, Ithaca, New York

Funding: Work supported by the National Science Foundation, the US Department of Energy, and the Japan/US Cooperation Program

In concert with the ILC global design effort, the CESR is being converted into ILC Damping Ring Test Accelerator. The vacuum system is undergoing staged reconfigurations to support both the CesrTA physics goals and the CHESS X-ray sources. Six superconducting wigglers were moved to a sector with zero-dispersion. The sector is densely populated with beam instrumentation and diagnostic devices. A new photon stop chamber will be used to handle the high synchrotron radiation power generated from the SCWs at high positron beam energy. A 12-m long gate-valve isolated straight sector was created in a second location, where many electron-cloud diagnostic chambers will be installed and tested. We also configured two very short sections in the arcs, with additional gate valves, to provide flexibility of exchanging various meter-long test chambers with minimum impact to the operations. Many retarding field analyzers were integrated into the vacuum modifications in SCWs, dipoles, and drifts to study EC growth and suppression techniques. Creating environments where both local and collaborator provided equipment can be easily installed has been a major objective in the modifications.

• J.P. Alexander, C.J. Conolly, E. Fontes, W.H. Hopkins, B. Kreis, H. Liu, A. Lyndaker, M.A. Palmer, D.P. Peterson, P. Revesz, J.J. Savino, R.D. Seeley
  CLASSE, Ithaca, New York
• J.W. Flanagan
  KEK, Ibaraki

Funding: NSF

We report on the performance goals and design of the CESRTA x-ray beam size monitor (xBSM). The xBSM resolution must be sufficient to measure vertical beam sizes under 20um. The xBSM images 2–4keV synchrotron radiation photons onto one-dimensional photodiode array. Instrumentation in the dedicated x-ray beam line includes upstream interchangeable optics elements (slits, coded apertures, and Fresnel zone plates), a monochrometer and the InGaAs photodiode detector. To provide sufficient x-ray flux in 2 GeV operation, the beam line is evacuated, with only a thin diamond window isolating the detector vacuum from the damping ring. The readout is a beam-synchronized FADC that is sufficient to measure consecutive bunches independently in a 4ns bunch spacing configuration.

• 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.

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