Comparison between measured and simulated X-ray flux from different undulators at SOLEIL

At SOLEIL, Insertion Devices (IDs) performances are first evaluated with the electron beam commissioning then by the study of the radiation properties with the beamline. Spectra calculated from magnetic measurements with Synchrotron Radiation Workshop code and the ones measured on the beamline are compared. Even and odd harmonics width are measured and spatial distributions at a fixed energy are checked for several gap and phase values. Radiation properties are detailed in the cases of a 20 mm period planar in-vacuum undulator (U20), a 42 mm period APPLE II device (HU42) and a 80 mm period APPLE II device (HU80) generating non periodic magnetic fields components.