Calculation of double scattering of X-rays in two scattering geometries for a compressible fluid (argon)

Numerical estimates of double scattering of X-rays have been made in cylindrical and parallel-plate geometries for fluid argon in two states. For the cylindrical geometry the ratio of double scattering to single scattering is ~0.01 and independent of scatter angle to a first approximation, and thus does not seriously effect estimates of the radial distribution function. For the parallel-plate geometry the ratio is to a first approximation linear with angle and increases to ~0.15 at high angles; it thus seriously effects estimates of the radial distribution function and direct correlation function. The ratio can reach very high levels at low scatter angles if primary scattering is low.