[ Identification | Description | Input parameters | Output parameters | Links ]

# The `SANS_Guinier` Component

Sample for Small Angle Neutron Scattering: Guinier model

## Identification

- Author: Henrich Frielinghaus
- Origin: FZ-Juelich/FRJ-2/IFF/KWS-2
- Date: Sept 2004
- Version: 1.3

## 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, zthick=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 "zthick" | 0.5
Rg | Angs | : Radius of Gyration | 100
qmax | AA-1 | : Maximum scattering vector | 0.03
xwidth | m | : horiz. dimension of sample, as a width (m) | 0.01
yheight | m | : vert.. dimension of sample, as a height (m) | 0.01
zthick | m | : thickness of sample (m) | 0.001

## Output parameters

Name | Unit | Description | Default
--- | --- | --- | ---
q_v |  |  |

## Links

- Source code for `SANS_Guinier.comp`.
- Sans_spheres component

[ Identification | Description | Input parameters | Output parameters | Links ]