[ Identification | Description | Input parameters | Links ]
Incoherent ComponentA Double-cylinder shaped incoherent scatterer (like Vanadium) with both elastic and quasielastic (Lorentzian) components. No multiple scattering (but approximation available). Absorption included. Sample focusing: The area to scatter to is a disk of radius 'focus_r' situated at the target. This target area may also be rectangular if specified focus_xw and focus_yh or focus_aw and focus_ah, respectively in meters and degrees. The target itself is either situated according to given coordinates (x,y,z), or defined with the relative target_index of the component to focus to (next is +1). This target position will be set to its AT position. When targeting to centered components, such as spheres or cylinders, define an Arm component where to focus to. Sample shape: Sample shape may be a cylinder, a sphere, a box or any other shape box/plate: xwidth x yheight x zdepth (thickness=0) hollow box/plate:xwidth x yheight x zdepth and thickness>0 cylinder: radius x yheight (thickness=0) hollow cylinder: radius x yheight and thickness>0 sphere: radius (yheight=0 thickness=0) hollow sphere: radius and thickness>0 (yheight=0) any shape: geometry=OFF file The complex geometry option handles any closed non-convex polyhedra. It computes the intersection points of the neutron ray with the object transparently, so that it can be used like a regular sample object. It supports the PLY, OFF and NOFF file format but not COFF (colored faces). Such files may be generated from XYZ data using: qhull < coordinates.xyz Qx Qv Tv o > geomview.off or powercrust coordinates.xyz and viewed with geomview or java -jar jroff.jar (see below). The default size of the object depends of the OFF file data, but its bounding box may be resized using xwidth,yheight and zdepth. Example: Incoherent(radius=0.05,focus_r=0.035, pack=1, target_index=1) Incoherent(geometry="socket.off",focus_r=0.035, pack=1, target_index=1)
| Name | Unit | Description | Default | |
| geometry | str | Name of an Object File Format (OFF) or PLY file for complex geometry. The OFF/PLY file may be generated from XYZ coordinates using qhull/powercrust | 0 | |
| radius | m | Outer radius of sample in (x,z) plane | 0 | |
| xwidth | m | Horiz. dimension of sample (bounding box if off file), as a width | 0 | |
| yheight | m | Vert. dimension of sample (bounding box if off file), as a height. A sphere shape is used when 0 and radius is set | 0 | |
| zdepth | m | Depth of sample (bounding box if off file) | 0 | |
| thickness | m | Thickness of hollow sample | 0 | |
| target_x | 0 | |||
| target_y | m | position of target to focus at | 0 | |
| target_z | 0 | |||
| focus_r | m | Radius of disk containing target. Use 0 for full space | 0 | |
| focus_xw | m | horiz. dimension of a rectangular area | 0 | |
| focus_yh | m | vert. dimension of a rectangular area | 0 | |
| focus_aw | deg | horiz. angular dimension of a rectangular area | 0 | |
| focus_ah | deg | vert. angular dimension of a rectangular area | 0 | |
| target_index | 1 | Relative index of component to focus at, e.g. next is +1 | 0 | |
| pack | 1 | Packing factor | 1 | |
| p_interact | 1 | MC Probability for scattering the ray; otherwise transmit | 1 | |
| f_QE | 1 | Fraction of quasielastic scattering (rest is elastic) | 0 | |
| gamma | 1 | Lorentzian width of quasielastic broadening (HWHM) | 0 | |
| Etrans | meV | Global energy-transfer, for use in inelastic settings | 0 | |
| deltaE | meV | Width in energy around Etrans, for use in inelastic settings | 0 | |
| sigma_abs | barns | Absorption cross section pr. unit cell at 2200 m/s | 5.08 | |
| sigma_inc | barns | Incoherent scattering cross section pr. unit cell | 5.08 | |
| Vc | Unit cell volume [AA^3] | 13.827 | ||
| concentric | 1 | Indicate that this component has a hollow geometry and may contain other components. It should then be duplicated after the inside part (only for box, cylinder, sphere) | 0 | |
| order | 1 | Limit multiple scattering up to given order 0:all (default), 1:single, 2:double, ... | 0 |
| AT ( | , | , | ) RELATIVE | |||
|---|---|---|---|---|---|---|
| ROTATED ( | , | , | ) RELATIVE |
Incoherent.comp.
[ Identification | Description | Input parameters | Links ]
Generated on 2024-01-03 11:47:43