1998•Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topicsRequires access
High current operation of a storage-ring free-electron laser
R. Roux, Marie-Emmanuelle Couprie, R.J. Bakker, D. Garzella, D. Nutarelli, Laurent Nahon, M. Billardon
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Abstract
The operation of storage-ring free-electron lasers (SRFEL) at high current still represents a challenge because of the growth of longitudinal beam instabilities. One of these, the quadrupolar coherent synchrotron oscillation, is very harmful for free-electron-laser (FEL) operation. On the Super-ACO storage ring, they either prevent the FEL start-up, or result in a very poor stability of the FEL source. A new feedback system to damp the quadrupolar coherent synchrotron oscillation has been installed on the ring and the stabilized beam parameters have been systematically measured. As a result, the FEL gain is higher and the FEL operates more easily and with a higher average power. Its stability, which is very critical for user applications, has been significantly improved as it has been observed via systematic measurements of FEL dynamics performed with a double sweep streak camera.