Sample for Small Angle Neutron Scattering: Guinier model

Identification

Author: Henrich Frielinghaus

Origin: FZ-Juelich/FRJ-2/IFF/KWS-2

Date: Sept 2004

Version:(Unknown)

Description

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)

WARNING: This is a contributed Component.

Input parameters

Parameters in boldface are required;
the others are optional.

Name

Unit

Description

Default

transm

1

(coherent) transmission of sample for the optical path "zdepth"