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McStas: Guide_anyshape_r

[ Identification | Description | Input parameters | Links ]

The Guide_anyshape_r Component

Reflecting surface (guide and mirror) with any shape, defined from an OFF file and a patch to allow m-, alpha- and W-values added per polygon face. Derived from Guide_anyshape / Guide_anyshape_r .


  • Site:
  • Author: Emmanuel Farhi, adapted by Peter Link and Gaetano Mangiapia
  • Origin: ILL/MLZ
  • Date: August 4th 2010


This is a reflecting object component, derived from Guide_anyshape.
Its shape, as well as m-, alpha- and W-values (IN THIS ORDER) for each face, are defined from
an OFF file, given with its file name. The object size is set as given from the file, where
dimensions should be in meters. The bounding box may be re-scaled by specifying
xwidth,yheight,zdepth parameters. The object may optionally be centered when
using 'center=1'.

If in input only the values of R0 and Qc are specified, leaving m, alpha and W all null, then
Guide_anyshape_g will use the values of these last three parameters that are specified in the OFF
file for each face: floating point based values may be provided for them.
In case at least one among m, alpha and W is not null, then Guide_anyshape_g will use these
values as input (common for all the faces), ignoring those specified in the OFF file

The complex OFF/PLY geometry option handles any closed non-convex polyhedra.
It supports the OFF and NOFF file format but not COFF (colored faces).
Standard .OFF files may be generated from XYZ data using:
qhull < Qx Qv Tv o >
and viewed with geomview or java -jar jroff.jar (see below).
The default size of the object depends of the OFF file data, but its
bounding box may be resized using xwidth,yheight and zdepth.
PLY geometry files are also supported.

This component does take into account gravitation accurately.

Input parameters

Parameters in boldface are required; the others are optional.
xwidthmRedimension the object bounding box on X axis is non-zero0
yheightmRedimension the object bounding box on Y axis is non-zero0
zdepthmRedimension the object bounding box on Z axis is non-zero0
center1When set to 1, the object will be centered w.r.t. the local coordinate frame0
transmit1When true, non reflected neutrons are transmitted through the surfaces, instead of being absorbed. No material absorption is taken into account though0
R01Low-angle reflectivity0.99
QcAA-1Critical scattering vector0.0219
alphaAASlope of reflectivity0
m1m-value of material. Zero means completely absorbing.0
WAA-1Width of supermirror cut-off0
geometrystrName of the OFF/PLY file describing the guide geometry0


[ Identification | Description | Input parameters | Links ]

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

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