### Specular simulation with a rough sample

This example demonstrates how to compute reflected signal from a multilayered sample with surface roughness. All the experiment layout is exactly the same as the one described in reflectometry tutorial, but now all the layers (except the ambient media) have roughness on the top surface. The roughness is characterized by root-mean-square deviation from the mean surface position $\sigma = 1$ nm.

When comparing the result of the simulation to the result obtained in the reflectometry tutorial, one can notice up to two orders of magnitude attenuation of the reflected signal due to the roughness of the sample.

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58  #!/usr/bin/env python3 """ Example of simulating a reflectometry experiment with a rough sample using BornAgain. """ import bornagain as ba from bornagain import deg, angstrom, nm def get_sample(): """ Defines sample and returns it """ # creating materials m_ambient = ba.MaterialBySLD("Ambient", 0, 0) m_ti = ba.MaterialBySLD("Ti", -1.9493e-06, 0) m_ni = ba.MaterialBySLD("Ni", 9.4245e-06, 0) m_substrate = ba.MaterialBySLD("SiSubstrate", 2.0704e-06, 0) # creating layers ambient_layer = ba.Layer(m_ambient) ti_layer = ba.Layer(m_ti, 30*angstrom) ni_layer = ba.Layer(m_ni, 70*angstrom) substrate_layer = ba.Layer(m_substrate) # defining roughness roughness = ba.LayerRoughness() roughness.setSigma(1*nm) # creating multilayer multi_layer = ba.MultiLayer() multi_layer.addLayer(ambient_layer) for i in range(10): multi_layer.addLayerWithTopRoughness(ti_layer, roughness) multi_layer.addLayerWithTopRoughness(ni_layer, roughness) multi_layer.addLayerWithTopRoughness(substrate_layer, roughness) return multi_layer def get_simulation(sample, scan_size=500): """ Defines and returns a specular simulation. """ simulation = ba.SpecularSimulation() scan = ba.AngularSpecScan(1.54*angstrom, scan_size, 0, 2*deg) simulation.setScan(scan) simulation.setSample(sample) return simulation if __name__ == '__main__': import ba_plot sample = get_sample() simulation = get_simulation(sample) ba_plot.run_and_plot(simulation) 
SpecularSimulationWithRoughness.py