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#!/usr/bin/env python3
# /// script
# requires-python = ">=3.10"
# dependencies = ["bornagain>=25,<26"]
# ///
"""
Mesocrystal positional disorder (Debye-Waller damping) below and above
the substrate critical angle (alpha_c ~ 0.2 deg). Below alpha_c the
scattering wavevector has a sizable imaginary qz; the DWF uses the
analytic square q.q = qx^2+qy^2+qz^2, the correct continuation of
|q|^2 to complex q.
"""
import bornagain as ba
ba.require_versions("bornagain>=25,<26")
from bornagain import deg, nm, nm2, R3
def get_sample(sigma):
# Materials
particle_color = (0.86, 0.24, 0.18)
particle_mat = ba.RefractiveMaterial("Particle", particle_color, 6e-05, 2e-07)
substrate_color = (0.28, 0.57, 0.82)
substrate_mat = ba.RefractiveMaterial("Substrate", substrate_color, 6e-06, 2e-07)
vacuum = ba.Vacuum()
# Basis particle and 3D lattice
inner_ff = ba.Sphere(2.5*nm)
inner_particle = ba.Particle(particle_mat, inner_ff)
lattice = ba.Lattice3D(R3(6*nm, 0, 0), R3(0, 6*nm, 0), R3(0, 0, 6*nm))
crystal = ba.Crystal(inner_particle, lattice, sigma)
# Mesocrystal: shaped crystal
outer_ff = ba.Cylinder(15*nm, 120*nm)
outer_particle = ba.Mesocrystal(crystal, outer_ff)
# Layers
top_layer = ba.Layer(vacuum)
top_layer.deposit2D(ba.Dilute2D(0.0005/nm2, outer_particle))
top_layer.setNumberOfSlices(20)
# Sample
sample = ba.Sample()
sample.addLayer(top_layer)
sample.addLayer(ba.Layer(substrate_mat))
return sample
def simulate(alpha_i, sigma):
n = 200
beam = ba.Beam(1e9, 0.1*nm, alpha_i)
detector = ba.SphericalDetector(1, -0.01*deg, 0.01*deg, n, 0, 2*deg)
simulation = ba.ScatteringSimulation(beam, get_sample(sigma), detector)
return simulation.simulate()
if __name__ == '__main__':
sigmas = [0*nm, 0.5*nm, 1.0*nm, 1.5*nm]
panels = [(0.08*deg, 'evanescent'), (0.20*deg, 'propagating')]
results = []
_, axes = ba.plt.subplots(1, 2, figsize=(12, 5), sharey=True)
for ax, (alpha_i, regime) in zip(axes, panels):
for sigma in sigmas:
result = simulate(alpha_i, sigma)
results.append(result)
ax.semilogy(result.yCenters()/deg, result.flatVector(),
label=f'sigma = {sigma/nm:.1f} nm')
ax.set_title(f'alpha_i = {alpha_i/deg:.2f} deg ({regime})')
ax.set_xlabel('alpha_f (deg)')
ax.legend()
axes[0].set_ylabel('Intensity')
ba.plt.tight_layout()
ba.showSample3D(get_sample(sigmas[0]), sample_size=220*nm, seed=0)
ba.plt.show()
|
BornAgain
≻ git-develop
≻ Documentation ≻ Examples ≻ GISAS ≻ Structures and correlations ≻ Mesocrystal evanescent
