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

14.16  The Guide_m McStas Component

Release: McStas 1.12c

Neutron guide.

Identification

Description

Models a rectangular guide tube centered on the Z axis. The entrance lies in the X-Y plane. 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: 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

%VALIDATION May 2005: extensive internal test, no bugs found Validated by: K. Lieutenant

%BUGS This component does not work with gravitation on. Use component Guide_gravity then.

Input parameters

Parameters in boldface are required; the others are optional.

Name

Unit

Description

Default

reflect

str

Reflectivity file name. Format [q(Å^-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_left

1

Low-angle reflectivity, left mirrror.

0.99

R0_right

1

Low-angle reflectivity, right mirror.

0.99

R0_top

1

Low-angle reflectivity, top mirror.

0.99

R0_bottom

1

Low-angle reflectivity, bottom mirror.

0.99

Qc_left

Å\(^{-1}\)

Critical scattering vector, left mirrror.

0.0219

Qc_right

Å\(^{-1}\)

Critical scattering vector, right mirror.

0.0219

Qc_top

Å\(^{-1}\)

Critical scattering vector, top mirror.

0.0219

Qc_bottom

Å\(^{-1}\)

Critical scattering vector, bottom mirror.

0.0219

aleft

Å

Slope of reflectivity, left mirrror.

6.07

aright

Å

Slope of reflectivity, right mirror.

6.07

atop

Å

Slope of reflectivity, top mirror.

6.07

abottom

Å

Slope of reflectivity, bottom mirror.

6.07

mleft

1

m-value of material. Zero means completely absorbing, left mirrror.

2

mright

1

m-value of material. Zero means completely absorbing, right mirror.

2

mtop

1

m-value of material. Zero means completely absorbing, top mirror.

2

mbottom

1

m-value of material. Zero means completely absorbing, bottom mirror.

2

W_left

Å\(^{-1}\)

Width of supermirror cut-off, left mirrror.

0.003

W_right

Å\(^{-1}\)

Width of supermirror cut-off, right mirror.

0.003

W_top

Å\(^{-1}\)

Width of supermirror cut-off, top mirror.

0.003

W_bottom

Å\(^{-1}\)

Width of supermirror cut-off, bottom mirror.

0.003

W

Å\(^{-1}\)

Overall width of supermirror cut-off, overwrites values from individual mirrors

0

m

1

Overall m-value of supermirrors, overwrites values from individual mirrors

0

alpha

Å

Overall slope of reflectivity, overwrites values from individual mirrors

0

R0

1

Overall, low-angle reflectivity, overwrites values from individual mirrors

0

Qc

Å\(^{-1}\)

Overall, critical scattering vector, overwrites values from individual mirrors

0

Links