Modelling of radio emission in the SLAC T-510 experiment using microscopic Geant4 simulations

The SLAC T-510 experiment was designed to verify established microscopic models for simulation of radio emission from air-showers by reproducing the physics under controlled lab conditions. For this verification, the simulation toolkit Geant4 was expanded by the calculation of the emitted radio signal with the 'endpoint' and the 'ZHS' formalisms in parallel. We present and compare the results of the two simulation approaches, taking into account the details of the experimental set-up such as the beam energy, target geometry and material, and the magnetic field configuration. We put special emphasis on the discussion of the effects due to refraction and transition radiation and show a comparison of the simulation results with the measured data of the SLAC T-510 Experiment.