Cornell University, Department of Physics, Ithaca, New York
CLASSE, Ithaca
University of Minnesota, Minneapolis, Minnesota
CESR-LEPP, Ithaca, New York
Technion, Haifa
In April 2008, we propose to begin operation of the Cornell Electron Storage Ring (CESR) as a test accelerator, CesrTA, for International Linear Collider (ILC) damping ring research. Utilizing 12 damping wigglers, the baseline CesrTA lattice at 2.0 GeV will offer a natural geometric emittance of 2.25 nm. An experimental program has been laid out which focuses on several key areas of damping rings R&D. First we will test vacuum chamber designs to suppress electron cloud growth in the wiggler magnets. Secondly, we will develop correction, tuning and emittance monitoring strategies to achieve vertical emittances of a few picometers. As part of this effort we will validate alignment and survey techniques being developed by the Linear Collider Alignment and Survey group (LiCAS) for curved tunnel applications. After achieving ultra-low emittance, we intend to explore the impact of the electron cloud, the fast ion instability and other beam dynamics effects on ultra-low emittance beams. Finally, we plan to test various technical systems required for the ILC damping rings. This paper provides an update on conceptual design issues for CesrTA and describes the experimental program in detail.
CLASSE, Ithaca
CHESS, Ithaca, New York
Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
Cornell University, Department of Physics, Ithaca, New York
The status of plans for an Energy-Recovery Linac (ERL) X-ray facility at Cornell University is described. Currently, Cornell operates the Cornell High Energy Synchrotron Source (CHESS) at the CESR ring and the ERL is planned to be an extension to the CESR ring with the addition of a 5-GeV superconducting c.w. linac. Topics covered in this paper include the full layout on the Cornell campus, the different operation modes of the accelerator, methods to limit emittance growth, control of beam-ion effects and ways to limit transverse instabilities. As an upgrade of the CESR ring, special attention is given to reuse of many of the existing components. The very small electron-beam emittances would produce an x-ray source that is highly superior than any existing storage-ring light source. The ERL includes 18 X-ray beamlines optimized for specific areas of research that are currently being defined by an international group of scientists. This planned upgrade illustrates how other existing storage rings could be upgraded to work as ERL light sources with vastly improved beam qualities and with limited dark time for x-ray users.
CLASSE, Ithaca
Six 1300 MHz superconducting niobium 2-cell cavities are manufactured for the prototype of Cornell ERL injector to boost the energy of a high current, low emittance beam produced by a DC gun. Designed for high current beam acceleration, these cavities have new characteristics as compared to previously developed low-current cavities such as those for TTF. Precision manufacture is emphasized for a better straightness of the cavity axis so as to avoid unwanted emittance dilution. We present the manufacturing, processing and vertical test performance of these cavities. We also present the impact of new cavity characteristics to the cavity performance as learnt from vertical tests. Solutions for improving cavity performance are discussed.