MeV-energy x rays from inverse compton scattering with laser-wakefield accelerated electrons.

We report the generation of MeV x rays using an undulator and accelerator that are both driven by the same 100-terawatt laser system. The laser pulse driving the accelerator and the scattering laser pulse are independently optimized to generate a high energy electron beam (>200 MeV) and maximize the output x-ray brightness. The total x-ray photon number was measured to be ∼1×10(7), the source size was 5 µm, and the beam divergence angle was ∼10 mrad. The x-ray photon energy, peaked at 1 MeV (reaching up to 4 MeV), exceeds the thresholds of fundamental nuclear processes (e.g., pair production and photodisintegration).

Relativistic MeV photoelectrons from the single atom response of argon to a 10 19 W/cm2 laser field.

We present photoelectron measurements from argon ionization at 10(19) W/cm(2). Photoelectrons with energies above 400 keV, including a 1.2 MeV cutoff, are in quantitative agreement with a semiclassical, relativistic 3D ionization model that includes a nonparaxial laser field. L-shell photoelectrons have energies and momentum dominated by the field, including the acceleration out of the focus. Yields and angular distributions at 60 keV come from valence shell ionization by strong fields where rescattering and atomic processes determine photoelectron final states.