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10.17 The Powder_process McXtrace Component
A sample component implementing a powder scattering process
Identification
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Author: Mads Bertelsen and Erik B Knudsen
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Origin: ESS DMSC & DTU Physics & United Neux
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Date: 20.08.15
Description
This Union_process is based on the PowerN.comp component.
Part of the Union components, a set of components that work together and thus separates geometry and physics within McXtrace. The use of this component requires other components to be used.
1) One specifies a number of processes using process components like this one 2) These are gathered into material definitions using Union_make_material 3) Geometries are placed using Union_box / Union_cylinder, assigned a material 4) A Union_master component placed after all of the above
Only in step 4 will any simulation happen, and per default all geometries defined before the master, but after the previous will be simulated here.
There is a dedicated manual available for the Union_components
Algorithm: Described elsewhere
Input parameters
Parameters in boldface are required; the others are optional.
|
Name |
Unit |
Description |
Default |
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|
reflections |
string |
Input file for reflections. No scattering if NULL or ”” [string] |
”NULL” |
|
material |
str |
Reflection list for power |
”NULL” |
|
packing_factor |
1 |
How dense is the material compared to optimal 0-1 |
1 |
|
Vc |
Å\(^{3}\) |
Volume of unit cell=nb atoms per cell/density of atoms. |
0 |
|
delta_d_d |
0/1 |
Global relative delta_d_d/d broadening when the ’w’ column is not available. Use 0 if ideal. |
0 |
|
DW |
1 |
Global Debye-Waller factor when the ’DW’ column is not available. Use 1 if included in F2 |
0 |
|
nb_atoms |
1 |
Number of sub-unit per unit cell, that is ratio of sigma for chemical formula to sigma per unit cell |
1 |
|
density |
g/cm\(^{3}\) |
Density of material. rho=density/weight/1e24*N_A. |
0 |
|
weight |
g/mol |
Atomic/molecular weight of material. |
0 |
|
barns |
1 |
Flag to indicate if —F—ˆ2 from ’reflections’ is in barns or fmˆ2 (barns=1 for laz, barns=0 for lau type files). |
1 |
|
Strain |
ppm |
Global relative delta_d_d/d shift when the ’Strain’ column is not available. Use 0 if ideal. |
0 |
|
interact_fraction |
1 |
How large a part of the scattering events should use this process 0-1 (sum of all processes in material = 1) |
-1 |
|
format |
no quotes |
Name of the format, or list of column indexes (see Description). |
{0, 0, 0, 0, 0, 0, 0, 0, 0} |
|
mat_format |
vector |
List order in reflection list file |
{0,0,0,0,0} |
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Links
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Component source code found in file Powder_process.comp.
