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
In an energy recovery linac (ERL) where beam-loss has to be minimal, and where beam positions and emittances have to be very stable in time, optic errors and beam instabilities due to ion effects have to be avoided. Here we explain why ion clearing electrodes are the least unattractive way of eliminating ions in an ERL and we present calculations of the remnant ion density and its effect on the beam. We also show a design of the clearing electrodes that should be distributed around the accelerator and illustrate their wake-field properties.