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McStas: Union_abs_logger_2D_space

[ Identification | Description | Input parameters | Links ]

The Union_abs_logger_2D_space Component

A sample component to separate geometry and phsysics


  • Site:
  • Author: Mads Bertelsen
  • Origin: ESS DMSC
  • Date: 19.06.20


Part of the Union components, a set of components that work together and thus
separates 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) Logger and conditional components can be placed which will record what happens
5) A Union_master component placed after all of the above

Only in step 5 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 component is an absorption logger, and thus placed in point 4) above.

A absorption logger will log something for each absorption event happening
in the geometry or geometries on which it is attached. These are specified
in the target_geometry string. By leaving it blank, all geometries are
logged, even the ones not defined at this point in the instrument file.
Multiple geometries are specified as a comma separated list.

This absorption logger stores the absorbed weight in a histogram spanning two
spatial directions. The position of the event is projected onto this plane.
The plotted data is very useful when ensuring the simulated geometry matches
the intentions. It is not recommended to use this tool for safety concerns,
as for example to estimate activity of a sample after irradiation.

The spatial plane in which the histogram is performed are chosen with the
D_direction_1 and D_direction_2 parameters which can be "x", "y" or "z".
The D1_min and D1_max parameters sets the limits for the first axis, and
D2_min / D2_max likewise for the second axis.

This absorption logger needs to be placed in space, the position is recorded in
the coordinate system of the logger component.

It is possible to attach one or more conditional components to this absorption
logger. Such a conditional component would impose a condition on the state of
the neutron after the Union_master component that executes the simulation,
and the absorption logger will only record the event if this condition is true.

To use the logger_conditional_extend function, set it to some integer value n
and make and extend section to the master component that runs the geometry.
In this extend function, logger_conditional_extend[n] is 1 if the conditional
stack evaluated to true, 0 if not. This way one can check what rays is logged
using regular McStas monitors. Only works if a conditional is applied to this

Input parameters

Parameters in boldface are required; the others are optional.
target_geometrystringComma separated list of geometry names that will be logged, leave empty for all volumes (even not defined yet)"NULL"
D_direction_1stringDirection for first axis ("x", "y" or "z")"x"
D1_min1histogram boundary, min position value for first axis-0.2
D1_max1histogram boundary, max position value for first axis0.2
n11number of bins for first axis100
D_direction_2stringDirection for second axis ("x", "y" or "z")"z"
D2_min1histogram boundary, min position value for second axis-0.2
D2_max1histogram boundary, max position value for second axis0.2
n21number of bins for second axis100
filenamestringFilename of produced data file"NULL"
order_total1Only log rays that have scattered n times, -1 for all orders-1
order_volume1Only log rays that have scattered n times in the same geometry, -1 for all orders-1
logger_conditional_extend_index1If a conditional is used with this logger, the result of each conditional calculation can be made available in extend as a array called "logger_conditional_extend", and one would then access logger_conditional_extend[n] if logger_conditional_extend_index is set to n-1


[ Identification | Description | Input parameters | Links ]

Generated on 2024-01-03 11:47:43

Last Modified: Tuesday, 16-Apr-2024 20:05:22 CEST
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