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Mesocrystal particles example

Scattering from cylindrically shaped mesocrystals on a substrate.

  • The sample is made of cylinder-shaped mesocrystals with outer dimensions: $R = 20$ nm, $H = 50$ nm.
  • The lattice axes are directed along x, y and z, with lattice parameter $5$ nm in each direction.
  • The nodes are spheres with $R = 2$ nm.
  • The planar distribution of the particles is diluted and random.
  • The incident wavelength is equal to 0.1 nm.
  • The incident angles are $\alpha_i = 0.2 ^{\circ}$ and $\varphi_i = 0^{\circ}$.

3D visualization

Scattering intensity

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#!/usr/bin/env python3
"""
Cylindrical mesocrystal on a substrate.
Calculation using exact computation and 
an approximate algorithm of the Fourier sum with a cutoff.
"""
import bornagain as ba
from bornagain import ba_plot as bp, deg, nm, R3


def get_sample():
    # Materials
    material_particle = ba.RefractiveMaterial("Particle", 0.0006, 2e-08)
    material_substrate = ba.RefractiveMaterial("Substrate", 6e-06, 2e-08)
    vacuum = ba.RefractiveMaterial("Vacuum", 0, 0)

    # Basis particle
    inner_ff = ba.Sphere(3*nm)
    inner_particle = ba.Particle(material_particle, inner_ff)

    # 3D lattice
    lattice = ba.Lattice3D(R3(8*nm, 0, 0), R3(0, 8*nm, 0),
                           R3(0, 0, 8*nm))

    # Crystal
    crystal = ba.Crystal(inner_particle, lattice)

    # Mesocrystal: shaped crystal
    outer_ff = ba.Cylinder(20*nm, 50*nm)
    outer_particle = ba.Mesocrystal(crystal, outer_ff)

    # Layers
    layer_1 = ba.Layer(vacuum)
    layer_1.depositParticle(0.0001, outer_particle)
    layer_2 = ba.Layer(material_substrate)

    # Sample
    sample = ba.Sample()
    sample.addLayer(layer_1)
    sample.addLayer(layer_2)

    return sample


def get_simulation(sample):
    beam = ba.Beam(1e9, 0.1*nm, 0.2*deg)
    n = 200
    detector = ba.SphericalDetector(n, -2*deg, 2*deg, n, 0, 2*deg)
    simulation = ba.ScatteringSimulation(beam, sample, detector)
    return simulation


def simulate(title, use_fourier):
    sample = get_sample()
    simulation = get_simulation(sample)
    if use_fourier:
        simulation.options().setMesoReciprocalSum(True, 2.5)
    result = simulation.simulate()
    result.setTitle(title)
    return result


if __name__ == '__main__':
    results = [
        simulate('exact sum', False),
        simulate('Fourier sum', True),
    ]
    bp.plot_to_row(results)
    bp.plt.show()
auto/Examples/scatter2d/Mesocrystal.py