Monte-Carlo event generation for the interaction of x-ray laser fields and hot electrons

We present a novel approach for an event generator inherently using exact QED descriptions to predict the results of high-energy electron-photon scattering experiments that can be performed at modern x-ray laser facilities.
With the advent of advanced laser systems producing high-frequency x-ray beams, e.g. the EuropeanXFEL as a prominent example, a regime of laser-plasma interaction is reached, where all-optical methods are no longer applicable. Instead, the interaction of hot electrons and the x-ray laser pulse needs to be modeled with a QED-driven approach. Future experiments taking place at HED-HIBEF, LCLS, and other facilities targeting this regime, will encounter processes in x-ray scattering from (laser-driven) relativistic electrons, where the effects of the energy spectrum of the laser field as well as multi-photon interactions can not be neglected anymore.
In contrast to the application window of existing QED-PIC codes, our event generator makes use of the fact, that the classical nonlinearity parameter barely approaches unity in high-frequency regimes. Therefore, based on a momentum-space Furry-picture formulation of strong-field QED, this allows taking the finite bandwidth of the x-ray laser into account in the description of the QED-like multi-photon interaction. Consequently, we exploit these effects in Compton scattering, Breit-Wheeler pair production, and trident pair production in x-ray laser fields.