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

 Linux Install (deb/rpm)
 Mac OS X Install
 Unix Install (src code)
 Windows Install
 Other Downloads (share)

Mailing list

Search web/mailinglist

 McStas manual
 Known problems
 C Compilers




Report bugs


McStas Ubuntu live-dvd

McStas: Virtual_mcnp_ss_Guide Component

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

The Virtual_mcnp_ss_Guide Component

Neutron guide initiated using Virtual_mcnp_ss_input.comp, and replacing Virtual_mcnp_ss_output.comp - see examples//Test_SSR_SSW_Guide.instr


  • Author: Esben klinkby and Peter Willendrup
  • Origin: Risoe-DTU
  • Date: Marts 2012
  • Version: $Revision$


Based on Kristian Nielsens Guide.comp
Models a rectangular guide tube centered on the Z axis. The entrance lies
in the X-Y plane.
The component must be initiated after Virtual_mcnp_ss_input.comp,
and replaces Virtual_mcnp_ss_output.comp  - see examples/Test_SSR_SSW_Guide.instr.
The basic idea is, that rather than discarding unreflected (i.e. absorbed)
neutrons at the guide mirrors, these neutron states are stored on disk. 
Thus, after the McStas simulation a MCNP simulation can be performed based
 on the un-reflected neutrons - intended for shielding studies.
(details: we don't deal with actual neutrons, so what is transferred between 
simulations suites is neutron state parameters: pos,mom,time,weight. The latter is
whatever remains after reflection.

For details on the geometry calculation see the description in the McStas
reference manual.
The reflectivity profile may either use an analytical mode (see Component
Manual) or a 2-columns reflectivity free text file with format
[q(Angs-1) R(0-1)].

Example: Virtual_mcnp_ss_Guide(w1=0.1, h1=0.1, w2=0.1, h2=0.1, l=2.0,
          R0=0.99, Qc=0.021, alpha=6.07, m=2, W=0.003

Upcomming in 2012 based on ESS shielding 
Validated by: D. Ene & E. Klinkby

This component does not work with gravitation on. Use component Guide_gravity then 
(doesn't work with SSR/SSW unfortunately)

Example values: m=4 Qc=0.0219 W=1/300 alpha=6.49 R0=1

Input parameters

Parameters in boldface are required; the others are optional.
Name Unit Description Default
reflect str Reflectivity file name. Format [q(Angs-1) R(0-1)] 0
w1 m Width at the guide entry  
h1 m Height at the guide entry  
w2 m Width at the guide exit  
h2 m Height at the guide exit  
l m length of guide  
R0 1 Low-angle reflectivity 0.99
Qc AA-1 Critical scattering vector 0.0219
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

Output parameters

Name Unit Description Default


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

Generated automatically by McDoc, Peter Willendrup <> / Fri Mar 17 20:40:06 2017

Last Modified: Friday, 17-Mar-2017 21:40:06 CET
Search website mailinglist archive GitHub repos