Component Manual for the Neutron Ray-Tracing Package McStas, version 3.8.6

14.57  The Foil_flipper_magnet McStas Component

A magnet with a spin-flip foil inside

Identification

Description

ESCRIPTION A magnet with a spin-flip foil inside

This component models a magnet with a constant magnetic field and a slanted magnetized foil inside acting as a spin-flipper. This arrangement may be used to target the geometry of a Spin-Echo SANS instrument (Rekveldt, NIMB, 1997 || Rekveldt, Rev Sci Instr. 2005). In its most basic form a SE-SANS instrument nrelies on inclined field regions of constant magnetic field, which can be difficult to realize. Instead it is possible to emulate such regions using a magnetized foil.

In this component th emagntzied foil is modelled as a canted (by the angle phi) mathematical plane inside a region of constant magnetic field of dimensions (xwidth,yheight,zdepth). Furthermore, exponetially decaying stray fields from the constant field region may be specified by giving parameters (Bxwidth,Byheight,Bzdepth) > (xwidth,yheight,zdepth).

Input parameters

Parameters in boldface are required; the others are optional.

Name

Unit

Description

Default

stray_field

Toggle for modelling of stray fields.

1

xwidth

m

width of the magnet

yheight

m

height of the magnet

zdepth

m

thickness of the magnet

Bxwidth

m

width of the B-field of thev component

-1

Byheight

m

height of the B-field of the component

-1

Bzdepth

m

thickness of the B-field of the component

-1

phi

rd

angle (from the xz-plane) of the foil-spinflipper inside the magnet

0.0

foilthick

um

Thickness of the magnetized foil

0.0

Bx

T

Parameter used for x composant of field.

By

T

Parameter used for y composant of field.

Bz

T

Parameter used for z composant of field.

foil_in

Toggle for optional foil in the flipper.

1

verbose

Toggle verbose mode

0

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