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

McStas

About McStas
 Conditions of use
 Authors/Contacts
 Project funding

Download
 Components
 Other Downloads (share)

Mailing list

Search web/mailinglist

Documentation
 Wiki (GitHub)
 McStas manual
 Publications

Links

Report bugs (GitHub)

Code-repository (GitHub)


McStas: Pol_mirror Component

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

The Pol_mirror Component

Polarising mirror.

Identification

  • Author: Peter Christiansen
  • Origin: RISOE
  • Date: July 2006
  • Version:(Unknown)

Description

This component models a rectangular infinitely thin mirror.
For an unrotated component, the mirror surface lies in the Y-Z
plane (ie. parallel to the beam).
It relies on similar physics as the Monochromator_pol.
The reflectivity function (see e.g. share/ref-lib for examples) and parameters
are passed to this component to give a bigger freedom.
The up direction is hardcoded to be along the y-axis (0, 1, 0)
IMPORTANT: At present the component only works correctly for polarization along the up/down
direction and for completely unpolarized beams, i.e. sx=sy=sz=0 for all rays.

For now we assume:
P(Transmit|Q) = 1 - P(Reflect|Q)
i.e. NO ABSORPTION!


The component can both reflect and transmit neutrons with a respective proportion
depending on the p_reflect parameter:
  p_reflect=-1 Reflect and transmit (proportions given from reflectivity) [default]
  p_reflect=1 Only handle reflected events
  p_reflect=0 Only handle transmitted events (reduce weight)
  p_reflect=0-1 Both transmit and reflect with fixed statistics proportions

The parameters can either be
double pointer initializations (e.g. {R0, Qc, alpha, m, W})
or table names (e.g."supermirror_m2.rfl" AND useTables=1).
NB! This might cause warnings by the compiler that can be ignored.

Examples:
Reflection function parametrization
Pol_mirror(zwidth = 0.40, yheight = 0.40, rUpFunc=StdReflecFunc, rUpPar={1.0, 0.0219, 6.07, 2.0, 0.003})

Table function
Pol_mirror(zwidth = 0.40, yheight = 0.40, rUpFunc=TableReflecFunc, rUpPar="supermirror_m2.rfl", rDownFunc=TableReflecFunc, rDownPar="supermirror_m3.rfl", useTables=1)

See also the example instrument Test_Pol_Mirror (under tests).

GRAVITY: YES

%BUGS
NO ABSORPTION

Input parameters

None.

Links


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

Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Wed Jan 12 15:13:20 2022


Last Modified: Wednesday, 12-Jan-2022 16:13:20 CET
Search website mailinglist archive GitHub repos