Evaluation of femtosecond X-rays produced by Thomson scattering under linear and nonlinear interactions between a low-emittance electron beam and an intense polarized laser light

The mechanisms of Thomson scattering under linear and nonlinear interactions are discussed theoretically and used to evaluate characters of femtosecond (fs) X-rays produced by collision between a low-emittance electron beam and an intense polarized laser light. In the evaluation, we start from the differential cross section of the Thomson scattering under the linear interaction, and calculate the effects of the interaction angle and the laser light polarization on the production of the fs X-rays. The energy and emission angular distributions of the produced fs X-rays are calculated under linear and nonlinear interactions between the electron beam and polarized laser light. A 214 keV (5.8×10−3 nm) X-ray beam with a pulse length of 228 fs and an intensity of 3×107 photons/pulse is numerically obtained by using the listed parameters of a 100 fs pulse laser and a low-emittance electron beam. The pulse length of the X-rays is expected to be in the duration of 100 fs by developing a 50 fs pulse laser (wavelength of 1 μm) and focusing the beam size down to 20 μm for both electron beam and laser light.