Precision X-ray optics for fundamental interactions in atomic physics, resolving discrepancies in the X-ray regime

Reliable knowledge of the complex X-ray form factor (Re(f) and f ") is requ ired for many fields including crystallography, medical diagnosis and XAFS studies. However, there are discrepancies between theory and theory, experi ment and experiment and theory and experiment of 10% and more, over central X-ray energies. Discrepancies exist for most elements, despite claimed exp erimental accuracies of 1%. This paper summarises the current variation bet ween experimental and theoretical results, and outlines key issues for obta ining experimental accuracies of 1% in critical wavelength ranges for selec ted elements to address these issues. This paper critically surveys availab le experimental data for attenuation coefficients and suggests a procedure for obtaining significantly higher accuracy measurements in the future.