[ Identification | Description | Input parameters | Links ]

`V_sample`

Component-
**Site:** -
**Author:**Kim Lefmann and Kristian Nielsen -
**Origin:**Risoe -
**Date:**15.4.98

A Double-cylinder shaped incoherent scatterer (a V-sample) with both elastic and quasielastic (Lorentzian) components. No multiple scattering. Absorbtion included. The shape of the sample may be a box with dimensions xwidth, yheight, zthick. 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. Example: V_sample(radius_i=0.001,radius_o=0.01,h=0.02,focus_r=0.035,pack=1, target_index=1)

Name | Unit | Description | Default | |

radius | m | Outer radius of sample in (x,z) plane | 0 | |

thickness | m | Thickness of outer wall | 0 | |

zdepth | m | depth of box sample | 0 | |

Vc | Unit cell volume [AA^3] | 13.827 | ||

sigma_abs | barns | Absorbtion cross section pr. unit cell | 5.08 | |

sigma_inc | barns | Incoherent scattering cross section pr. unit cell | 5.08 | |

radius_i | m | radius-thickness | 0 | |

radius_o | m | Same as radius | 0 | |

h | m | Same as yheight | 0 | |

focus_r | m | Radius of disk containing target. Use 0 for full space | 0 | |

pack | 1 | Packing factor | 1 | |

frac | 1 | MC Probability for scattering the ray; otherwise penetrate | 1 | |

f_QE | 1 | Fraction of quasielastic scattering (rest is elastic) | 0 | |

gamma | 1 | Lorentzian width of quasielastic broadening (HWHM) | 0 | |

target_x | 0 | |||

target_y | m | position of target to focus at | 0 | |

target_z | 0 | |||

focus_xw | m | horiz. dimension of a rectangular area | 0 | |

focus_yh | m | vert. dimension of a rectangular area | 0 | |

focus_aw | deg | angular width dimension of a rectangular area | 0 | |

focus_ah | deg | angular height dimension of a rectangular area | 0 | |

xwidth | m | horiz. dimension of sample | 0 | |

yheight | m | vert. dimension of sample | 0 | |

zthick | m | Same as zdepth | 0 | |

rad_sphere | m | Radius for a spherical sample | 0 | |

sig_a | barns | Same as sigma_abs | 0 | |

sig_i | barns | Same as sigma_inc | 0 | |

V0 | Same as Vc [AA^3] | 0 | ||

target_index | 1 | relative index of component to focus at, e.g. next is +1 | 0 | |

multiples | 1 | Apply crude estimate for multiple scattering | 1 |

AT ( | , | , | ) RELATIVE | |||
---|---|---|---|---|---|---|

ROTATED ( | , | , | ) RELATIVE |

- Source code for
`V_sample.comp`

. - Test
- results (not up-to-date).
- The test/example instrument vanadium_example.instr.
- The test/example instrument QENS_test.instr.

[ Identification | Description | Input parameters | Links ]

Generated on 2023-09-19 20:01:36