Mesocrystal

This examples deals with the modelling of a cylindrically shaped mesocrystal on a substrate. With this scope, three lattice basis vectors are defined, using spherical particles as the base of a first crystal structure. This base crystal structure is later combined with a cylinder form factor to form the mesocrystal.

The basis vectors of the base crystal are $5 \, {\rm nm}$ each, the sperical particles have a radius of $2 \, {\rm nm}$ and the cylindrical form factor to shape the mesocrystal is $20 \, {\rm nm}$ in radius and $50 \, {\rm nm}$ in height.

Intensity image

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#!/usr/bin/env python3
"""
Cylindrical mesocrystal on a substrate
"""
import bornagain as ba
from bornagain import deg, nm, kvector_t


def get_sample():
    """
    Returns a sample with a cylindrically shaped mesocrystal on a substrate.
    """

    # Define materials
    material_Particle = ba.HomogeneousMaterial("Particle", 0.0006, 2e-08)
    material_Substrate = ba.HomogeneousMaterial("Substrate", 6e-06, 2e-08)
    material_Vacuum = ba.HomogeneousMaterial("Vacuum", 0.0, 0.0)

    # Define form factors
    ff_1 = ba.FormFactorFullSphere(2.0*nm)
    ff_2 = ba.FormFactorCylinder(20.0*nm, 50.0*nm)

    # Define particles
    particle_1 = ba.Particle(material_Particle, ff_1)

    # Define 3D lattices
    lattice = ba.Lattice3D(ba.kvector_t(5.0*nm, 0.0*nm, 0.0*nm),
                           ba.kvector_t(0.0*nm, 5.0*nm, 0.0*nm),
                           ba.kvector_t(0.0*nm, 0.0*nm, 5.0*nm))

    # Define crystals
    crystal = ba.Crystal(particle_1, lattice)

    # Define mesocrystals
    particle_2 = ba.MesoCrystal(crystal, ff_2)

    # Define particle layouts
    layout = ba.ParticleLayout()
    layout.addParticle(particle_2, 1.0)
    layout.setWeight(1)
    layout.setTotalParticleSurfaceDensity(0.01)

    # Define layers
    layer_1 = ba.Layer(material_Vacuum)
    layer_1.addLayout(layout)
    layer_2 = ba.Layer(material_Substrate)

    # Define sample
    sample = ba.MultiLayer()
    sample.addLayer(layer_1)
    sample.addLayer(layer_2)

    return sample


def get_simulation(sample):
    beam = ba.Beam(1.0, 0.1*nm, ba.Direction(0.2*deg, 0*deg))
    detector = ba.SphericalDetector(200, -2*deg, 2*deg, 200, 0*deg, 2*deg)
    simulation = ba.GISASSimulation(beam, sample, detector)
    return simulation


if __name__ == '__main__':
    import ba_plot
    sample = get_sample()
    simulation = get_simulation(sample)
    ba_plot.run_and_plot(simulation)
MesoCrystal.py