• C. Evain, M.-E. Couprie, J.-M. Filhol, M. Labat, A. Nadji
  SOLEIL, Gif-sur-Yvette
• A. Zholents
  ANL, Argonne

SOLEIL is presently installing a laser bunch slicing set-up to produce ultra-short X-ray pulses. We propose a method to generate coherent synchrotron radiation at high harmonics in a storage ring using an echo scheme. Like in the method proposed recently for free electron lasers, the echo scheme uses two modulators and two dispersive sections. We show that this can be done at the synchrotron SOLEIL by adapting the classical slicing scheme. In the present study at SOLEIL, the two laser/electrons interactions are planned to occur in two out of vacuum wigglers of period 150 mm, and the high harmonic radiation will be emitted in an APPLE-II type undulator with a period of 44mm or 80 mm in the beamline TEMPO or with a period of 52 mm in the beamline DEIMOS.