We used the x-ray extended-range technique to measure the x-ray mass attenuation coefficients of silicon with an accuracy between 0.27% and 0.5% in the $5\mathrm{keV}-20\mathrm{keV}$ energy range. Subtraction of the x-ray scattering contribution enabled us to derive the corresponding x-ray photoelectric absorption coefficients and determine the absolute value of the imaginary part of the atomic form factor of silicon. Discrepancies between the experimental values of the mass attenuation coefficients and theoretically calculated values are discussed. New approaches to the theoretical calculation will be required to match the precision and accuracy of the experimental results.

• Received 10 December 2002

DOI:https://doi.org/10.1103/PhysRevA.67.042716