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12.23 The AF_HB_1D_process McStas Component
1D Antiferromagnetic Heisenberg chain
Identification
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Author: Mads Bertelsen
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Origin: University of Copenhagen
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Date: 20.08.15
Description
1D Antiferromagnetic Heisenberg chain
Part of the Union components, a set of components that work together and thus sperates geometry and physics within McStas. 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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atom_distance |
Å |
Distance between atom’s in chain |
1 |
|
number_density |
1/Å\(^{3}\) |
Number of scatteres per volume |
0 |
|
unit_cell_volume |
Å\(^{3}\) |
Unit cell volume (set either unit_cell_volume or number density) |
0 |
|
A_constant |
unitless |
Constant from Müller paper 1981, probably somewhere between 1 and 1.5 |
1 |
|
J_interaction |
meV |
Exchange constant |
1 |
|
packing_factor |
1 |
How dense is the material compared to optimal 0-1 |
1 |
|
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 |
|
init |
string |
Deprecated and unused. Accepted so that instruments written for McStas/McXtrace 3.8.7 and earlier, which name the Union_init component here, still compile. |
"" |
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Links
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Component source code found in file AF_HB_1D_process.comp.
