[ Identification | Description | Input parameters | Links ]
MCViNE_DGSSXRes_process ComponentScatters towards a target disk (position target_x/y/z or target_index, radius focus_r) and picks the arrival time at the target uniformly in tof_at_target +/- dtof/2 (absolute neutron time, s). The final speed follows from the flight distance. Weight: solid_angle/4pi * dtof * dE/dt * vf/vi, as in MCViNE. Record ki/kf with monitors to build the resolution ellipsoid (similar in purpose to McStas' TOFRes_sample, with MCViNE's weighting). Union process. Part of the Union components: define this process, collect it into a material with Union_make_material (absorption is set there with my_absorption, the absorption inverse penetration depth at 2200 m/s), assign the material to Union_box/Union_cylinder/Union_sphere/Union_mesh geometries, and add a Union_master after them. Geometry, attenuation and multiple scattering are handled by Union_master; this component provides the MCViNE kernel: the scattering coefficient and the final-state sampling (weight). Isotropic process (powder/liquid-like); rotation is irrelevant. The target is the Union focusing of the geometry (target_index / target_x.. and focus_r / focus_xw,focus_xh / focus_aw,focus_ah on Union_box etc.). The kernel code is shared with the standalone component MCViNE_DGSSXRes (mcvine-lib.c). Uses share/mcvine-lib.h/.c and share/mcvine-union-lib.h/.c; the process type MCViNE is declared in share/union-lib.h and registered with Union_master in share/mcvine-union-lib.h. Example: MCViNE_DGSSXRes_process(focus_r=0.0125, tof_at_target=0.0052, dtof=1e-5, scattering_coefficient=10)
| Name | Unit | Description | Default | |
| tof_at_target | s | Desired absolute time of arrival at the target | 0.001 | |
| dtof | s | Width of the time window | 1e-5 | |
| scattering_coefficient | m^-1 | Scattering coefficient (inverse penetration depth for scattering) | 0 | |
| sigma_scat | barn | Alternative: scattering cross section per unit cell (used when Vc>0) | 0 | |
| Vc | AA^3 | Unit cell volume; when >0 the coefficient is sigma_scat/Vc | 0 | |
| packing_factor | 1 | Packing factor (scales the scattering coefficient) | 1 | |
| interact_fraction | 1 | Union: fraction of interactions forced to this process (-1: by cross section) | -1 | |
| init | string | Deprecated and unused, accepted like on the other Union components (see Union_init). | "" |
| AT ( | , | , | ) RELATIVE | |||
|---|---|---|---|---|---|---|
| ROTATED ( | , | , | ) RELATIVE |
MCViNE_DGSSXRes_process.comp.
[ Identification | Description | Examples | Input parameters | Links ]
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