Sample for Small Angle Neutron Scattering, Guinier model
Author: Henrich Frielinghaus
Origin: FZ-Juelich/FRJ-2/IFF/KWS-2
Date: Sept 2004
Sample that scatters with a Guinier shape. This is just an example where analytically an integral exists. The neutron paths are proportional to the intensity (low intensity > few paths).
Guinier function (Rg) a = Rg*Rg/3 propability_unscaled = q * exp(-a*q*q) integral_prop_unscal = 1/(2*a) * (1 - exp(-a*q*q))
propability_scaled = 2*a * q*exp(-a*q*q) / (1 - exp(-a*q*q))
integral_prop_scaled = (1 - exp(-a*q*q)) / (1 - exp(-a*qmax*qmax))
In this simulation method many paths occur for high propability. For simulation of low intensities see SANS_AnySamp.
Sample components leave the units of flux for the probability of the individual paths. That is more consitent than the Sans_spheres routine. Furthermore one can simulate the transmitted beam. This allows to determine the needed size of the beam stop. Only absorption has not been included yet to these sample-components. But thats really nothing.
Example: SANS_Guinier(transm=0.5, Rg=100, qmax=0.03, xwidth=0.01, yheight=0.01, zdepth=0.001)
Parameters in boldface are required; the others are optional.
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Name |
Unit |
Description |
Default |
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transm |
1 |
(coherent) transmission of sample for the optical path "zdepth" |
0.5 |
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Rg |
Å |
Radius of Gyration |
100 |
|
qmax |
Å\(^{-1}\) |
Maximum scattering vector |
0.03 |
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xwidth |
m |
horiz. dimension of sample, as a width |
0.01 |
|
yheight |
m |
vert.. dimension of sample, as a height |
0.01 |
|
zdepth |
m |
thickness of sample |
0.001 |
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Component source code found in file SANS_Guinier.comp.
Sans_spheres component