McStas logo McStas - A neutron ray-trace simulation package ILL; PSI; ESS Niels Bohr Institute DTU Physics NEXMAP


About McStas
 Conditions of use
 Project funding

 Other Downloads (share)

Mailing list

Search web/mailinglist

 Wiki (GitHub)
 McStas manual


Report bugs (GitHub)

Code-repository (GitHub)

McStas: Mirror Component

[ Identification | Description | Input parameters | Output parameters | Links ]

The Mirror Component

Single mirror plate.


  • Author: Kristian Nielsen
  • Origin: Risoe
  • Date: August 1998
  • Version:(Unknown)


Single mirror plate (used to build guides in compound components).
The component Mirror models a single rectangular neutron mirror plate.
It can be used as a sample component or to e.g. assemble a complete neutron
guide by putting multiple mirror components at appropriate locations and
orientations in the instrument definition, much like a real guide is build
from individual mirrors.
Additionally, it may be centered in order to be used as a sample or
monochromator plate, else it starts from AT position.
Reflectivity is either defined by an analytical model (see Component Manual)
or from a two-columns file with q [Angs-1] as first and R [0-1] as second.
In the local coordinate system, the mirror lies in the first quadrant of the
x-y plane, with one corner at (0, 0, 0). Plane is thus perpendicular to the
incoming beam, and should usually be rotated.

Example: Mirror(xwidth=.1, yheight=.1,R0=0.99,Qc=0.021,alpha=6.1,m=2,W=0.003)

Example values: m=4 Qc=0.02 W=1/300 alpha=6.49 R0=1

Input parameters

Parameters in boldface are required; the others are optional.
Name Unit Description Default
reflect 0-1 [str] Name of reflectivity file. Format q(Angs-1) R 0
xwidth m width of mirror plate  
yheight m height of mirror plate  
R0 1 Low-angle reflectivity 0.99
Qc AA-1 Critical scattering vector 0.021
alpha AA Slope of reflectivity 6.07
m 1 m-value of material. Zero means completely absorbing. 2
W AA-1 Width of supermirror cut-off 0.003
center 1 if true (1), the Mirror is centered arount AT position. 0
transmit 1 When true, non reflected neutrons are transmitted through the mirror, instead of being absorbed. 0

Output parameters

Name Unit Description Default


[ Identification | Description | Input parameters | Output parameters | Links ]

Generated automatically by McDoc, Peter Willendrup <> / Wed Jan 12 15:13:31 2022

Last Modified: Wednesday, 12-Jan-2022 16:13:31 CET
Search website mailinglist archive GitHub repos