Radiation from a laser-plasma accelerated electron beam passing through an undulator

In the quest for ultra-compact sources, a test experiment is under preparation, to couple an electron beam from a laser driven plasma accelerator, stable and tunable in energy, to an undulator. The electron beam is generated in the colliding laser pulses scheme, by focusing two short and intense laser pulses in an underdense plasma plume. The electron bunch has an energy tunable in the range 100-300MeV with 1% energy spread, a length 10fs, a charge in the 10pC range, while its radius and divergence are respectively 1μm and 3mrad. As a first step toward a FEL experiment, the transport and radiation through an undulator of this short and compact electron beam is studied. Numerical predictions for the spontaneous emission through an undulator in the 40-120nm range is presented.