Predicting SAXS images beyond single scattering

Laser-generated solid density plasmas can be used to produce highly energetic electrons and ions. Diagnosing properties within those plasmas at nm length scales and down to fs time scales plays a crucial role in understanding the involved processes. This has only recently become feasible through the advent of X-Ray Free Electron Lasers (XFELs). XFELs now make experimental techniques like Small Angle X-Ray Scattering (SAXS) applicable to solid density plasmas. We present a scalable GPU-based software framework for simulating photon scattering processes of X-ray beams in matter using Monte-Carlo methods. These simulations enable us to produce synthetic SAXS signals from the interaction of a modeled X-ray pulse with an arbitrarily complex, 3D electron density distribution obtained e.g. from detailed particle-in-cell simulations. Our new framework allows for single and multiple scattering and is extendable to include complex physics processes like ionization, atomic excitation and de-excitation to further enhance its predictive capability.