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[ Identification | Description | Input parameters | Output parameters | Links ]
The Monochromator0 component
Non-flat monochromator crystal with multiple scattering
Identification
- Author: Thomas C Hansen
- Origin: ILL (Dif/D20)
- Date: 08 March 2000
- Version: 2.0
Description
Non-flat monochromator which uses a small-mosity approximation as well as the approximation vy^2 << vz^2 + vx^2. The crystal may be in transmission geometry as well as in reflection. Multiple scattering is possible. The individual reflectivity for each neutron is calculated from its velocity vector, the structure factor of the monochromator crystal and its mosaic. For an unrotated monochromator component, the crystal plane lies in the y-z plane (ie. parallel to the beam).
Input parameters
Parameters in boldface are required; the others are optional.| Name | Unit | Description | Default |
|---|---|---|---|
| xmin | m | Lower x-bound of crystal | |
| xmax | m | Upper x-bound of crystal | |
| zmin | m | Lower z-bound of crystal | |
| zmax | m | Upper z-bound of crystal | |
| ymin | m | Lower y-bound of crystal | |
| ymax | m | Upper y-bound of crystal | |
| mosh | min | Horizontal mosaic (FWHM) | |
| mosv | min | Vertical mosaic (FWHM) | |
| dist | m | Distance from target (sample), not yet used (17.2) | |
| xw | m | Width of target (sample), not yet used (0.01) | |
| write | 1 | Flag (1/0) to write debugging information in a file | |
| F2 | fm**2 | Structure factor of monochromator material | |
| Vc | AA**3 | Unit cell volume of monochromator material | |
| omega | deg | Rocking angle difference from Bragg reflection position (0) | |
| Q | 1/AA | Wavevector of scattering | |
| harmonic | 1 | Order of first higher, contamining harmonic (2 for Cu or HOPG, 3 for Ge) | |
| B | 1 | Debye-Waller factor of monochromator material | |
| LIMIT | 1 | Upper limit of multiple scattering events to avoid infinite loops (1001) | |
| blade | 1 | Number of blade in a focussing monochromator of several blades (0) | |
| present | 1 | Flag (1/0) of presence of the component in focussing monochromators with variable number of elements (1) |
Output parameters
None.Links
- Source code for
Monochromator0.comp. - Source code of d20adapt.instr, where this component is used
[ Identification | Description | Input parameters | Output parameters | Links ]
Generated automatically by McDoc, Kristian Nielsen <kristian.nielsen@risoe.dk> / Jan 22 2001
