[ Identification | Description | Input parameters | Links ]

# The `Powder_process` Component

Port of the PowderN process to the Union components

## Identification

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

## Description

    This Union_process is based on the PowderN.comp component originally written
    by P. Willendrup, L. Chapon, K. Lefmann, A.B.Abrahamsen, N.B.Christensen,
    E.M.Lauridsen.

    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 |
reflections | string | Input file for reflections. No scattering if NULL or "" [string] | "NULL" |
packing_factor | 1 | How dense is the material compared to optimal 0-1 | 1 |
Vc | AA^3 | Volume of unit cell=nb atoms per cell/density of atoms. | 0 |
delta_d_d | 0/1 | Global relative delta_d_d/d broadening when the 'w' column is not available. Use 0 if ideal. | 0 |
DW | 1 | Global Debye-Waller factor when the 'DW' column is not available. Use 1 if included in F2 | 0 |
nb_atoms | 1 | Number of sub-unit per unit cell, that is ratio of sigma for chemical formula to sigma per unit cell | 1 |
d_phi | deg | Angle corresponding to the vertical angular range to focus to, e.g. detector height. 0 for no focusing. | 0 |
density | g/cm^3 | Density of material. rho=density/weight/1e24*N_A. | 0 |
weight | g/mol | Atomic/molecular weight of material. | 0 |
barns | 1 | Flag to indicate if |F|^2 from 'reflections' is in barns or fm^2 (barns=1 for laz, barns=0 for lau type files). | 1 |
Strain | ppm | Global relative delta_d_d/d shift when the 'Strain' column is not available. Use 0 if ideal. | 0 |
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 |
format | no quotes | Name of the format, or list of column indexes (see Description). | {0, 0, 0, 0, 0, 0, 0, 0, 0} |

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

## Links

- Source code for `Powder_process.comp`.

[ Identification | Description | Input parameters | Links ]