7.9 The Pol_guide_vmirror McStas Component
Polarising guide with nvs x 2 supermirrors sitting in v-shapes inside, upgraded from original
single V-cavity.
Identification
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Author: Peter Willendrup
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Origin: DTU
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Date: June 2022
Description
Models a rectangular guide with entrance centered on the Z axis and with nvs x two
supermirrors sitting in v-shapes inside. The entrance lies in the X-Y plane. Draws a true
depiction of the guide with mirrors, and trajectories. The polarisation is handled similar to in
Monochromator_pol. The reflec functions are handled similar to Pol_mirror. The up direction
is hardcoded to be along the y-axis (0, 1, 0)
The reflectivity parameters can be 1. double pointer initializations with 5 parameters (e.g.
{R0, Qc, alpha, m, W} AND inputType=0), or 2. double pointer initializations with 6
parameters (e.g. {R0, Qc, alpha, m, W, beta} AND inputType=0), or 3. table names
(e.g."supermirror_m2.rfl" AND inputType=1), or 4. individually assigned values (e.g.
rR0=1.0, rQc=0.0217, ... etc AND inputType=2). NB! This might cause warnings by the
compiler that can be ignored. Note that the reflectivity functions that use with values and
those that use tables are different.
GRAVITY: YES
%BUGS No absorption by mirror.
Input parameters
Parameters in boldface are required; the others are optional.
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Name |
Unit |
Description |
Default |
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nvs |
1 |
Number of V-cavities across width of
guide |
1 |
|
xwidth |
m |
Width at the guide entry |
0.1 |
|
yheight |
m |
Height at the guide entry |
0.1 |
|
length |
m |
length of guide |
0.5 |
|
rR0 |
1 |
Cavity wall reflectivity below critical
scattering vector, use with inputType =
2 |
1.0 |
|
rQc |
Å\(^{-1}\) |
Cavity wall reflectivity critical scattering
vector, use natural Ni (m=1 definition)
value of 0.0217, use with inputType = 2 |
0.0217 |
|
ralpha |
Å |
Cavity wall slope of reflectivity, use with
inputType = 2 |
6.5 |
|
rmSM |
1 |
Cavity wall m-value of material. Zero
means completely absorbing. Use with
inputType = 2 |
2 |
|
rW |
Å\(^{-1}\) |
Cavity wall width of reflectivity cut-off,
use with inputType = 2 |
0.00157 |
|
rbeta |
Å\(^{2}\) |
Cavity wall curvature of reflectivity, use
with inputType = 2 |
80 |
|
rUpR0 |
1 |
Mirror spin up reflectivity below critical
scattering vector, use with inputType =
2 |
1.0 |
|
rUpQc |
Å\(^{-1}\) |
Mirror spin
up reflectivity critical scattering vector,
use natural Ni (m=1 definition) value of
0.0217, use with inputType = 2 |
0.0217 |
|
rUpalpha |
Å |
Mirror spin up slope of reflectivity, use
with inputType = 2 |
2.47 |
|
rUpmSM |
1 |
Mirror spin up m-value of material. Zero
means completely absorbing. Use with
inputType = 2 |
4 |
|
rUpW |
Å\(^{-1}\) |
Mirror spin up width of reflectivity
cut-off, use with inputType = 2 |
0.0014 |
|
rUpbeta |
Å\(^{2}\) |
Mirror spin up curvature of reflectivity,
use with inputType = 2 |
0 |
|
rDownR0 |
1 |
Mirror spin down reflectivity below
critical scattering vector, use with
inputType = 2 |
1.0 |
|
rDownQc |
Å\(^{-1}\) |
Mirror spin down reflectivity critical
scattering vector, use natural Ni (m=1
definition) value of 0.0217, use with
inputType = 2 |
0.0217 |
|
rDownalpha |
Å |
Mirror spin down slope of reflectivity, use
with inputType = 2 |
1 |
|
rDownmSM |
1 |
Mirror spin down m-value of material.
Zero means completely absorbing. Use
with inputType = 2 |
0.65 |
|
rDownW |
Å\(^{-1}\) |
Mirror spin down width of reflectivity
cut-off, use with inputType = 2 |
0.003 |
|
rDownbeta |
Å\(^{2}\) |
Mirror spin down curvature of
reflectivity, use with inputType = 2 |
0 |
|
debug |
1 |
if debug > 0 print out some internal
runtime parameters |
0 |
|
allow_inside_start |
1 |
Allow neutron to start inside cavity (no
propagation to entry plane) |
0 |
|
rPar |
1 |
Cavity wall parameters array for rFunc,
use with inputType = 0 |
{1.0, 0.0217,
6.5, 2,
0.00157, 80} |
|
rUpPar |
1 |
Mirror Parameters array for rUpFunc,
use with inputType = 0 |
{1.0, 0.0217,
2.47, 4,
0.0014} |
|
rDownPar |
1 |
Mirror Parameters for rDownFunc, use
with inputType = 0 |
{1.0, 0.0217,
1, 0.65,
0.003} |
|
rParFile |
|
Cavity wall parameters filename for
rFunc, use with inputType = 1 |
"" |
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rUpParFile |
|
Mirror Parameters filename for rUpFunc,
use with inputType = 1 |
"" |
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rDownParFile |
|
Mirror Parameters filename for
rDownFunc, use with inputType = 1 |
"" |
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