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Particles crossing an interface

In this example, very similar to our basic GISAS example, it is shown how to position particles in order to cross multilayer interfaces: the $z$ position of particles originally located within the air layer must be adjusted slightly downwards in order to cross the air-substrate interface.

The simulation kernel automatically detects particles crossing interfaces and adjusts the calculations accordingly, causing a drop on speed to complete each simulation.

The script below models a air-substrate bilayer in which cylindrical particles made of two materials are added to the air layer and their $z$ coordinate is shifted downwards in order to cross the air-substrate interface.

Scattering intensity

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#!/usr/bin/env python3
"""
Scattering from particles that cross the interface between vacuum and substrate.
"""
import bornagain as ba
from bornagain import ba_plot as bp, deg, nm, nm2, R3


def get_sample():
    # 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 = ba.Cylinder(5*nm, 5*nm)
    particle = ba.Particle(particle_mat, ff)
    particle.translate(0, 0, -3*nm)

    # Layers
    layer_1 = ba.Layer(vacuum)
    layer_1.deposit2D(ba.Dilute2D(0.0001/nm2, particle))
    layer_2 = ba.Layer(substrate_mat)

    # 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 = 100
    detector = ba.SphericalDetector(n, -1*deg, 1*deg, n, 0, 2*deg)
    simulation = ba.ScatteringSimulation(beam, sample, detector)
    return simulation


if __name__ == '__main__':
    sample = get_sample()
    ba.showSample3D(sample, sample_size=120*nm, seed=0)
    simulation = get_simulation(sample)
    result = simulation.simulate()
    bp.plot_datafield(result, unit_aspect=1)
    bp.plt.show()
auto/Examples/scatter2d/ParticleAcrossInterface.py