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McStas: Guide_anyshape

[ Identification | Description | Input parameters | Links ]

The Guide_anyshape Component

Reflecting surface (guide and mirror) with any shape, defined from an OFF file.

Identification

  • Site:
  • Author: Emmanuel Farhi
  • Origin: ILL
  • Date: August 4th 2010

Description

This is a reflecting object component. Its shape is 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'.

The reflectivity is specified either from the usual parametric description
R0,Qc,alpha,W,m, or from a reflectivity file 'reflect' with a 2 column
format [q(Angs-1) R(0-1)].

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).
Such files may be generated from XYZ data using:
qhull < coordinates.xyz Qx Qv Tv o > geomview.off
or
powercrust coordinates.xyz
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.

%BUGS
This component does take into account gravitation accurately.

Input parameters

Parameters in boldface are required; the others are optional.
NameUnitDescriptionDefault
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 reflectivity3
m1m-value of material. Zero means completely absorbing.2
WAA-1Width of supermirror cut-off0.003
reflectq(Angs-1) R(0-1)(str) Reflectivity file name. Format0
geometrystrName of the OFF/PLY file describing the guide geometry0
AT ( , , ) RELATIVE
ROTATED ( , , ) RELATIVE

Links


[ Identification | Description | Input parameters | Links ]

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


Last Modified: Wednesday, 03-Jan-2024 19:59:10 CET
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