Terrestrial experiments involving detached growth of GeSi crystals by the Bridgman technique have been performed in preparation for microgravity experiments to be conducted on the International Space Station. These experiments typically produce large GeSi crystals that are sectioned for microscopy, microprobe analysis, and electron-backscatter diffraction analysis. Accurate microanalysis of these crystals is essential for feedback to further growth experiments, but is problematic as the Ge-Si binary exhibits continuous solid solution and it is therefore difficult to prepare homogeneous intermediate standards. There are no experimental measurements on standards of known composition in the Ge-Si binary that could be used to evaluate analytical accuracy. The accuracy of analysis in mineral, oxide, and semiconductor systems has previously been studied using experimental x-ray intensity measurements, correction algorithms and their derived α-factors, and mass absorption coefficient data sets. This study continues that approach and includes results of Monte Carlo calculations in the Ge-Si binary.