Progress Toward An Erl Extension To Cesr

The status of plans for an Energy-Recovery Linac (ERL) x-ray facility at Cornell University are described. Cornell currently operates the Cornell High Energy Synchrotron Source (CHESS) at the CESR ring. The ERL is planned to be an extension to that ring by a 5-GeV superconducting c.w. linac. The very small electron-beam emittances would produce an x-ray source that is considerably better than any existing storage-ring light source. The ERL design that is presented has to allow for non-destructive transport of these small emittances. It includes up to 18 x-ray beamlines for specific areas of research that are currently being defined by an international community. Special attention is given to reuse of many of the existing ring components. Here it is described which subjects are being investigated or win have to be studied at Cornell to prepare for the construction of this new hard x-ray source; references to other contributions to this conference (PAC07) demonstrate this effort. This project illustrates how existing storage rings could be upgraded as ERL light sources with vastly improved beam qualities and with limited dark time for x-ray users. The presented list of research topics shows R&D issues for any such upgrade project.