X-ray free electron laser for electron–positron pair production on the nuclei

In the present paper the production of electron–positron pairs via the scattering of intense beam of X-ray quanta on an ion/nucleus beam is considered. The process is moderately nonlinear for X-ray wavelength where only a few hundred quanta are participating in comparison to laser beams where millions of photons are necessary, requiring fantastically large intensities of the optical beams. Our analysis shows that production of electron–positron pairs on the nuclei at the focus of X-ray beams expected for the planned X-ray FEL facilities is actually possible.