Double bent monochromator with multiple slabs
Author: <a href="mailto:plink@physik.tu-muenchen.de">Peter Link</a>.
Origin: Uni. Gottingen (Germany)
Date: Feb. 12,1999
Double bent monochromator which uses a small-mosaicity approximation as well as the approximation vy^2 << vz^2 + vx^2. Second order scattering is neglected. For an unrotated monochromator component, the crystal plane lies in the y-z plane (ie. parallel to the beam). When curvatures are set to 0, the monochromator is flat. The curvatures approximation for parallel beam focusing to distance L, with monochromator rotation angle A1 are: RV = 2*L*sin(DEG2RAD*A1); RH = 2*L/sin(DEG2RAD*A1);
Example: Monochromator_2foc(zwidth=0.02, yheight=0.02, gap=0.0005, NH=11, NV=11,
mosaich=30, mosaicv=30, r0=0.7, Q=1.8734)
Example values for lattice parameters
PG 002 DM=3.355 AA (Highly Oriented Pyrolytic Graphite) PG 004 DM=1.607 AA
Heusler 111 DM=3.362 Å (Cu2MnAl)
CoFe DM=1.771 AA (Co0.92Fe0.08)b Ge 311 DM=1.714 AA Si 111 DM=3.135 AA Cu 111 DM=2.087 AA Cu 002 DM=1.807 AA Cu 220 DM=1.278 AA Cu 111 DM=2.095 AA
Parameters in boldface are required; the others are optional.
|
Name |
Unit |
Description |
Default |
|
|
|||
|
reflect |
k, R |
reflectivity file name of text file as 2 columns |
0 |
|
zwidth |
m |
horizontal width of an individual slab |
0.01 |
|
yheight |
m |
vertical height of an individual slab |
0.01 |
|
gap |
m |
typical gap between adjacent slabs |
0.0005 |
|
NH |
columns |
number of slabs horizontal |
11 |
|
NV |
rows |
number of slabs vertical |
11 |
|
mosaich |
arcmin |
Horisontal mosaic FWHM |
30.0 |
|
mosaicv |
arcmin |
Vertical mosaic FWHM |
30.0 |
|
r0 |
1 |
Maximum reflectivity |
0.7 |
|
Q |
Å\(^{-1}\) |
Scattering vector |
1.8734 |
|
RV |
m |
radius of vertical focussing, flat for 0 |
0 |
|
RH |
m |
radius of horizontal focussing, flat for 0 |
0 |
|
DM |
Å |
monochromator d-spacing instead of Q=2*pi/DM |
0 |
|
mosaic |
arcmin |
sets mosaich=mosaicv |
0 |
|
width |
m |
total width of monochromator |
0 |
|
height |
m |
total height of monochromator |
0 |
|
verbose |
0/1 |
verbosity level |
0 |
|
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Component source code found in file Monochromator_2foc.comp.
Additional note from Peter Link.