CEBAF Energy Recovery Experiment

High current CW energy recovery linacs (ERLs) are seen as important elements in planned future facilities such as: next-generation light sources, electron coolers and electron-ion colliders. The Jefferson Lab FEL (5 mA, 50 MeV) has been the highest power superconducting ERL so far in operation. Full-scale demonstration of this technology with multiple cavities at the GeV energy scale is highly desirable. Such an experiment (E-02-102)¨ has recently been approved at Jefferson Lab. There are two phases to the proposed experiment. In the first, the beam would be accelerated in the North and South linacs to about 1 GeV and then decelerated in the North and South linacs to be dumped at the injection energy. This experiment requires a new half-wavelength (RF) magnetic chicane at the end of the South linac. The second phase is a current doubling experiment. The beam would be accelerated in the North and South linacs; it would then pass through a quarter-wavelength chicane, drift through the North and South linacs with no energy change, pass throughout the chicane a second time, and be decelerated in the North and South linacs and dumped. The effective gun current would thus be doubled. The experiments will involve careful measurements of all beam properties: energy, current, emittance, and beam halo. These are important parameters, crucial in characterizing the performance of energy recovery. Furthermore, this information will be valuable in advancing the planning, design and operation of future high-energy, high-current ERLs.