Cylinders and Prisms

Scattering from a mixture of cylinders and prisms without interference.

  • The sample comprises a substrate on which are deposited, in equal proportion, cylinders and prisms.
  • All particles are made of the same material.
  • Each type of particle has the same orientation.
  • The cylinders are 5 nm high and 5 nm in radius.
  • Each prism is 5 nm high with an equilateral triangular base, whose side length is equal to 10 nm.
  • There is no interference between the waves scattered by these particles. The distribution is therefore diluted.
  • The incident neutron beam is characterized by a wavelength of 1 Å.
  • The incident angles are αi = 0.2° and Φi = 0°.
  • The simulation is performed using the Distorted Wave Born Approximation (due to the presence of a substrate).


Real-space model: 
Intensity Image: 
Python Script: 
Mixture of cylinders and prisms without interference
import bornagain as ba
from bornagain import deg, angstrom, nm

def get_sample():
    Returns a sample with uncorrelated cylinders and prisms on a substrate.
    # defining materials
    m_air = ba.HomogeneousMaterial("Air", 0.0, 0.0)
    m_substrate = ba.HomogeneousMaterial("Substrate", 6e-6, 2e-8)
    m_particle = ba.HomogeneousMaterial("Particle", 6e-4, 2e-8)

    # collection of particles
    cylinder_ff = ba.FormFactorCylinder(5*nm, 5*nm)
    cylinder = ba.Particle(m_particle, cylinder_ff)
    prism_ff = ba.FormFactorPrism3(10*nm, 5*nm)
    prism = ba.Particle(m_particle, prism_ff)
    particle_layout = ba.ParticleLayout()
    particle_layout.addParticle(cylinder, 0.5)
    particle_layout.addParticle(prism, 0.5)
    interference = ba.InterferenceFunctionNone()

    # air layer with particles and substrate form multi layer
    air_layer = ba.Layer(m_air)
    substrate_layer = ba.Layer(m_substrate)
    multi_layer = ba.MultiLayer()
    return multi_layer

def get_simulation():
    Returns a GISAXS simulation with beam and detector defined.
    simulation = ba.GISASSimulation()
    simulation.setDetectorParameters(100, -1.0*deg, 1.0*deg,
                                     100, 0.0*deg, 2.0*deg)
    simulation.setBeamParameters(1.0*angstrom, 0.2*deg, 0.0*deg)
    return simulation

def run_simulation():
    Runs simulation and returns resulting intensity map.
    simulation = get_simulation()
    return simulation.getIntensityData()

if __name__ == '__main__':
    result = run_simulation()