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#!/usr/bin/env python3
# /// script
# requires-python = ">=3.10"
# dependencies = ["bornagain>=25,<26"]
# ///
"""
Cylinders of two different sizes in Decoupling Approximation,
Local Monodisperse Approximation and Size-Spacing Coupling Approximation
"""
import bornagain as ba
ba.require_versions("bornagain>=25,<26")
from bornagain import deg, nm
def get_sample(approximation):
"""
A sample with cylinders of two different sizes on a substrate
in radial paracrystal ordering.
"""
# Materials
particle_color = (0.86, 0.24, 0.18)
particle_mat = ba.RefractiveMaterial("Particle", particle_color, 0.0006, 2e-08)
substrate_color = (0.28, 0.57, 0.82)
substrate_mat = ba.RefractiveMaterial("Substrate", substrate_color, 6e-06, 2e-08)
vacuum = ba.Vacuum()
# Particles
ff_1 = ba.Cylinder(5*nm, 5*nm)
ff_2 = ba.Cylinder(8*nm, 8*nm)
particle_1 = ba.Particle(particle_mat, ff_1)
particle_2 = ba.Particle(particle_mat, ff_2)
# Layers
layer_1 = ba.Layer(vacuum)
layer_2 = ba.Layer(substrate_mat)
# Distribution function
profile = ba.Profile1DGauss(3*nm)
if (not approximation=='LMA' and
not approximation=='DA' and
not approximation=='SSCA'):
raise Exception('Unknown approximation')
if approximation == 'LMA':
"""
Local Monodisperse Approximation: two independent layouts
with their own distinct interference functions
"""
# Interference functions
layout_1 = ba.RadialParacrystal(particle_1, 16.8*nm, 1000*nm)
layout_2 = ba.RadialParacrystal(particle_2, 22.8*nm, 1000*nm)
layout_1.setProbabilityDistribution(profile)
layout_2.setProbabilityDistribution(profile)
# Populate layer with two independent layouts
layer_1.addDeposit2D(0.5, layout_1)
layer_1.addDeposit2D(0.5, layout_2)
else: # 'DA/SSCA'
# Particle mixture
mix = ba.Mixture()
mix.addParticle(particle_1, 4)
mix.addParticle(particle_2, 1)
layout = ba.RadialParacrystal(mix, 18*nm, 1000*nm)
profile = ba.Profile1DGauss(3*nm)
layout.setProbabilityDistribution(profile)
"""
The only difference between Decoupling Approximation and
Size-Spacing Coupling Approximation is that in SSCA there is
a position phase offset between fractions defined by 'kappa' parameter:
DA: kappa = 0 (default value)
SSCA: kappa = 1
"""
if approximation == 'SSCA':
layout.setKappa(1)
# Populate layer with the layout
layer_1.deposit2D(layout)
# 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, 0., 2*deg, n, 0., 2*deg)
simulation = ba.ScatteringSimulation(beam, sample, detector)
return simulation
def simulate(approximation):
sample = get_sample(approximation)
simulation = get_simulation(sample)
result = simulation.simulate()
result.setTitle(approximation)
return result
if __name__ == '__main__':
ba.showSample3D(get_sample('LMA'), sample_size=240*nm, seed=0)
results = [
simulate('LMA'),
simulate('DA'),
simulate('SSCA')
]
ba.plot2d_to_row(results, unit_aspect=1)
ba.plt.show()
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