[ Identification | Description | Input parameters | Links ]

# The `Incoherent_process` Component

A sample component to separate geometry and phsysics

## Identification

- Site:
- Author: Mads Bertelsen
- Origin: University of Copenhagen
- Date: 20.08.15

## Description

    This Union_process is based on the Incoherent.comp component originally written
    by Kim Lefmann and Kristian Nielsen

    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 |
sigma | barns | Incoherent scattering cross section | 5.08 |
f_QE | 1 | Fraction of quasielastic scattering (rest is elastic) [1] | 0 |
gamma | meV | Lorentzian width of quasielastic broadening (HWHM) [1] | 0 |
packing_factor | 1 | How dense is the material compared to optimal 0-1 | 1 |
unit_cell_volume | AA^3 | Unit cell volume | 13.8 |
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 | name of Union_init component (typically "init", default) | "init" |

AT ( | , | , |  | ) RELATIVE |  |
ROTATED ( | , | , |  | ) RELATIVE |

## Links

- Source code for `Incoherent_process.comp`.
- The test/example instrument Test_Phonon.instr.

[ Identification | Description | Input parameters | Links ]