[ Identification | Description | Input parameters | Links ]

# The `Union_conditional_PSD` Component

A conditional component in the shape of an area the neutrons must hit

## Identification

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

## Description

    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
    2) These are gathered into material definitions using Union_make_material
    3) Geometries are placed using Union_box/cylinder/sphere, 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 this master, but after the previous will be simulated here.

    There is a dedicated manual available for the Union components

    This is a conditional component that affects the loggers in the target_loggers
    string. When a logger is affected, it will only record events if the
    conditional is true at the end of the simulation of a ray in the master.
    Conditionals can be used to for example limit the loggers to rays that end
    within a certain energy range, time interval or similar.

    One can apply several conditionals to each logger if desired.

    In the extend section of a master, the tagging conditional can be acsessed by
    the variable name tagging_conditional_extend. Beware, that it only works as
    long as the tagging system is active, so you may want to increase the number
    of histories allowed by that master component before stopping.

    This conditional is a little special, because it needs to be placed in space.
    It's center location is like a psd.

    overwrite_logger_weight can be used to force the loggers this conditional
    controls to write the final weight for each scattering event, instead of the
    recorded value.

## Input parameters

Parameters in boldface are required; the others are optional.

Name | Unit | Description | Default |
target_loggers | string | Comma seperated list of loggers this conditional should affect | "NULL" |
master_tagging | 1 | Apply this conditional to the tagging system in next master | 0 |
tagging_extend_index | 1 | Not currently used | -1 |
xwidth | m | Width of target area |  |
yheight | m | Height of target area |  |
time_min | s | Min time (on psd), if not set ignored | 0 |
time_max | s | Max time (on psd), if not set ignored | 0 |
overwrite_logger_weight | 1 | Default = 0, overwrite = 1 | 0 |
init | string | Name of Union_init component (typically "init", default) | "init" |

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

## Links

- Source code for `Union_conditional_PSD.comp`.

[ Identification | Description | Input parameters | Links ]