Scattering from cylinders of two different sizes using the Size-Spacing Coupling Approximation.
The sample is made of cylinders deposited on a substrate.
The distribution of particles is made of:
80% of cylinders with radii and heights equal to $5$ nm
20% of cylinders with radii and heights equal to $8$ nm.
The interference function is Radial Paracrystal with a peak distance of $18$ nm and a damping length of $1$ $\mu$m.
The wavelength is equal to 0.1 nm.
The incident angles are $\alpha_i = 0.2 ^{\circ}$ and $\varphi_i = 0^{\circ}$.
The Size-Spacing Coupling Approximation is implemented using the function setApproximation. By default the Decoupling Approximation is used (see Size-distribution model: Decoupling Approximation).
For this size-distribution model, an additional dimensionless parameter, the coupling parameter Kappa, has to be specified (see line 33). It defines how the distance between particles is linked with their sizes.