Bug #1636

Unexpected wavelength depent intensity Roughness vs. ParticleLayout

Added by a.glavic about 4 years ago. Updated 3 months ago.

Status:RejectedStart date:14 Nov 2016
Priority:HighDue date:
Assignee:-% Done:


Target version:-


When implementing a DWBA model I would expect the intensities of the structure factors to mostly depend (in first order) on the values of k_i and k_f, as these define the Fresnel coefficients. For a simulation with different incident wavelength but same k_i I would expect a similar result, which might be a bit distorted due to different refraction.
Especially, I would expect that roughness scattering to behave the same way as scattering from particles when they occur within the same layer.

I have build a simulation with a set of layers, where layer 2 has a roughness and 2D paracrystal of cylinders. Simulating the GISANS from this model for different lambda and constant k_i yields virtually identical roughness scattering but 3 orders of magnitude different intensity from the particles.

(As I wasn't sure which layer the roughness needs to be in to have the same prefactors I repeated this with particles in layer 2 and roughness for layer 3. Beam and detector resolution is included to rule out numerical effects from the simulation grid.)

model_3.py Magnifier - used model script (7.7 KB) a.glavic, 14 Nov 2016 13:23

test_SF_rough_vs_particle.png - Comparison plot for different wavelength (410 KB) a.glavic, 14 Nov 2016 13:23


#1 Updated by wuttke about 4 years ago

  • Parent task set to #1438

#2 Updated by wuttke about 4 years ago

  • Parent task changed from #1438 to #1688

#3 Updated by a.glavic almost 4 years ago

I will have to test this again, but I think I found my mistake now. I did not define the materials correctly using SLD instead of delta.

#4 Updated by pospelov about 3 years ago

  • Status changed from New to Rejected

Rejected, see #1823

#5 Updated by wuttke 3 months ago

  • Parent task deleted (#1688)

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