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Polarized SANS

This example shows how to simulate polarized SANS with BornAgain, using the Born Approximation.

The main difference between simulating GISAS and SAS in BornAgain is the presence of only a single layer in the multilayer object. This triggers the software to calculate the differential scattering cross section in the Born Approximation.

In this example, a sample with a magnetic core-shell particle is constructed. Beam and detector are setup to detect the spin-flip scattering channel and the result of this simulation is plotted as usual.

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#!/usr/bin/env python3
"""
Simple example demonstrating how polarized SANS experiments can be
simulated with BornAgain.
"""
import bornagain as ba
from bornagain import ba_plot as bp, deg, nm, R3
import matplotlib.pyplot as plt


def get_sample():
    """
    A sample with a magnetic core-shell particle in a solvent.
    """

    # Materials
    B = R3(0, 1e7, 0)
    material_Core = ba.RefractiveMaterial("Core", 6e-06, 2e-08, B)
    material_Shell = ba.RefractiveMaterial("Shell", 1e-07, 2e-08)
    material_Solvent = ba.RefractiveMaterial("Solvent", 5e-06, 0)

    # Form factors
    ff_1 = ba.Sphere(10*nm)
    ff_2 = ba.Sphere(12*nm)

    # Particles
    particle_1 = ba.Particle(material_Core, ff_1)
    particle_1_position = R3(0, 0, 2*nm)
    particle_1.translate(particle_1_position)
    particle_2 = ba.Particle(material_Shell, ff_2)

    # Core shell particles
    particle = ba.CoreAndShell(particle_1, particle_2)

    # Particle layouts
    layout = ba.ParticleLayout()
    layout.addParticle(particle)
    layout.setTotalParticleSurfaceDensity(0.01)

    # Layers
    layer = ba.Layer(material_Solvent)
    layer.addLayout(layout)

    # Sample
    sample = ba.Sample()
    sample.addLayer(layer)

    return sample


def get_simulation(sample):
    """
    A polarized SANS simulation
    """
    n = 200

    # Beam from above (perpendicular to sample):
    beam = ba.Beam(1e9, 0.4*nm, 0.001*deg)

    # Detector opposite to source:
    detector = ba.SphericalDetector(n, -7*deg, 7*deg, n, -7*deg, 7*deg)

    beam.setPolarization(R3(0, 1, 0))
    detector.setAnalyzer(R3(0, -1, 0))

    return ba.ScatteringSimulation(beam, sample, detector)


if __name__ == '__main__':
    sample = get_sample()
    simulation = get_simulation(sample)
    result = simulation.simulate()
    bp.plot_simulation_result(result)
    plt.show()
auto/Examples/scatter2d/PolarizedSANS.py