Small angle X-ray scattering from helical filaments

The intensity of small angle X-ray scattering has been calculated for a dilute suspension of identical, randomly oriented particles composed of two rigid coaxial helical filaments with negligible cross section and uniform electron density. The scattering is also computed for particles consisting of a single helix. Numerical calculations have been made for several values of the helix parameters. A series of intensity curves illustrates the effect of these parameters on the scattered intensity. The calculated intensities can be used in analysis of scattering data from suspensions of helical macromolecules.