Effect of finite slit height on the tail of a small-angle X-ray scattering curve

The equation of a small-angle X-ray scattering intensity curve, which would fulfil exactly Porod's law and which could be obtained by using cameras with a rectangular, triangular, or one of a number of trapezoidal cross-sectional profiles of the intensity of the primary beam, has been calculated. The equation thus obtained can be used to determine the effect of finite slit height of the collimating system on the tail of the diffraction curve.