CLASSE, Ithaca, New York
Funding: Work supported by the National Science Foundation and the US Department of Energy
The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) for the investigation of the beam physics of a linear collider damping ring. The low beta interaction region optics have been replaced with simple FOFO lattice structures. Superconducting damping wigglers are located in straights where horizontal dispersion can be constrained to be zero to minimize horizontal emittance. The flexibility of the CESR optics allows for an energy reach of 1.5 GeV /beam→ 6.0GeV/beam and a wide range of emittances and radiation damping times. We exploit that flexibility for measurements of the dependencies of various phenomena, on energy, emittance, and damping rate. At 2GeV beam energy, with no damping wigglers, the minimum horizontal emittance is 10nm. With 16 meters of wiggler magnets operating at 1.9 T, the horizontal emittance is reduced by a factor of four to 2.5 nm and the radiation damping time to 56ms. With tuning and alignment we expect to reach a vertical emittance approaching that of the International Linear Collider (ILC) damping rings. We report on the details of the CesrTA optics and the measurements of optical parameters.
CLASSE, Ithaca, New York
Funding: Support provided by the US National Science Foundation and the US Department of Energy.
The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) for low emittance damping ring R&D for the International Linear Collider (ILC). We are developing low emittance tuning techniques with a goal of 1) achieving a vertical emittance approaching that of the ILC damping rings and 2) Gaining an understanding of the effectiveness of those techniques. We will use gain mapping to characterize beam position monitor (BPM) electrode gains, orbit response analysis to determine BPM button misalignments, betatron phase and coupling measurements to characterize optical errors, and orbit and dispersion measurements to locate sources of vertical dispersion. We are investigating a nondestructive dispersion measurement that depends on exciting a synchrotron oscillation and monitoring the phase and amplitude at each BPM. We have developed the analysis tools necessary to correct magnet and alignment errors. An x-ray beam size monitor is being deployed that will allow us to monitor vertical emittance in real time, allowing for empirical tuning of beam size. We will describe the measurement and correction techniques and show data demonstrating their efficacy.
CLASSE, Ithaca, New York
LBNL, Berkeley, California
KEK, Ibaraki
ANL, Argonne
Fermilab, Batavia
CalPoly, San Luis Obispo, CA
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
SLAC, Menlo Park, California
Cornell University, Ithaca, New York
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.
