Given a Simulation instance, adding a constant background to it is as easy as:
simulation.setBeamIntensity(1e6)

  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  #!/usr/bin/env python3 """ Cylinder form factor in DWBA with constant background """ import bornagain as ba from bornagain import deg, nm def get_sample(): """ Returns a sample with uncorrelated cylinders on a substrate. """ # Define materials material_Particle = ba.HomogeneousMaterial("Particle", 0.0006, 2e-08) material_Substrate = ba.HomogeneousMaterial("Substrate", 6e-06, 2e-08) material_Vacuum = ba.HomogeneousMaterial("Vacuum", 0, 0) # Define form factors ff = ba.FormFactorCylinder(5*nm, 5*nm) # Define particles particle = ba.Particle(material_Particle, ff) # Define particle layouts layout = ba.ParticleLayout() layout.addParticle(particle) layout.setTotalParticleSurfaceDensity(0.01) # Define layers layer_1 = ba.Layer(material_Vacuum) layer_1.addLayout(layout) layer_2 = ba.Layer(material_Substrate) # Define sample sample = ba.MultiLayer() sample.addLayer(layer_1) sample.addLayer(layer_2) return sample def get_simulation(sample): beam = ba.Beam(1e6, 0.1*nm, ba.Direction(0.2*deg, 0)) detector = ba.SphericalDetector(100, 2*deg, 1*deg, 1*deg) simulation = ba.GISASSimulation(beam, sample, detector) background = ba.ConstantBackground(1.0e+03) simulation.setBackground(background) return simulation if __name__ == '__main__': import ba_plot sample = get_sample() simulation = get_simulation(sample) ba_plot.run_and_plot(simulation)