Sources of radiation on ARC-EN-CIEL proposal

The ARC-EN-CIEL project [1] proposes a panoply of light sources for the scientific community. The choice to base the FEL sources on HGHG (High Gain Harmonic Generation) radiation and their Non Linear Harmonics seeded with the High order Harmonics generated in Gas (HHG) is further confirmed with the successful demonstration experiment of such a scheme at SCSS Prototype Accelerator in Japan [1]. In phase 1 (220 MeV), the radiation extends down to 30 nm, phase 1' (800 MeV) and phase 2(1 GeV), the radiation reaches 1 nm, with 30-100 fs pulses. The first FEL "LEL1" utilizes in-vacuum undulators of period 26 mm for the modulator, and APPLE-type radiators of period 30 mm, close to the standard SOLEIL insertion devices. The second FEL branch "LEL2" uses in-vacuum planar U18 undulators as radiator. In addition, THz radiation from the magnets of the compression chicanes will be provided and has been calculated using SRW. ARC-EN-CIEL Phase 3 adds ERL loops at 1 GeV and 2 GeV where undulators emit conventional synchrotron radiation above 10 keV from short period in-vacuum undulators and soft X ray using a variable polarisation undulator. An FEL oscillator in the 40-8 nm spectral range is installed in the 1 GeV loop. The HHG seeded "LEL4" uses the electron beam from the 2 GeV loop and further accelerated to 3 GeV for producing coherent light production below 1 nm Recent calculations and optimisations are presented.