### 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  #!/usr/bin/env python3 """ Example of simulating a reflectometry experiment with a rough sample using BornAgain. """ import bornagain as ba from bornagain import angstrom, ba_plot as bp, deg, nm def get_sample(): # 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) # 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) roughness = ba.LayerRoughness(1*nm) # Sample sample = ba.MultiLayer() sample.addLayer(ambient_layer) for _ in range(10): sample.addLayerWithTopRoughness(ti_layer, roughness) sample.addLayerWithTopRoughness(ni_layer, roughness) sample.addLayerWithTopRoughness(substrate_layer, roughness) return sample def get_simulation(sample): n = bp.simargs['n'] scan = ba.AlphaScan(n, 2*deg/n, 2*deg) scan.setWavelength(1.54*angstrom) return ba.SpecularSimulation(scan, sample) if __name__ == '__main__': bp.parse_args(sim_n=500) sample = get_sample() simulation = get_simulation(sample) result = simulation.simulate() bp.plot_simulation_result(result) 
Examples/specular/SpecularSimulationWithRoughness.py