Forchi`, V.F.
(Vincenzo Forchi`)

THPOS09 Electron-Beam Stabilization for the European Storage-Ring Free-Electron Laser at Elettra
Mauro Trovò, Daniele Bulfone, Miltcho B. Danailov, Giovanni De Ninno, Bruno Diviacco, Vincenzo Forchi`, Marco Lonza (Elettra, Basovizza, Trieste), Luca Giannessi (ENEA C.R. Frascati, Frascati - Roma)

The temporal structure of the storage-ring free-electron laser at Elettra shows high sensitivity to electron-beam instabilities. In fact, even small beam orbit oscillations (of the order of few microns) may perturb the FEL dynamics and periodically switch off the laser. In order to improve the FEL operation and performance, a longitudinal multi-bunch feedback and a local orbit feedback have been activated. This paper reports on the beneficial effect of these feedback systems. Plans for a future "slow" longitudinal feedback are also briefly described.