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

The Monochromator_curved Component

by Kristian Nielsen and Peter Link Double bent multiple crystal slabs with anisotropic gaussian mosaic.

Identification

Description

Double bent infinitely thin mosaic crystal, useful as a monochromator or
analyzer. which uses a small-mosaicity approximation and taking into account
higher  order scattering. The mosaic is anisotropic gaussian, with different
FWHMs in the Y and Z directions. The scattering vector is perpendicular to the
surface. For an unrotated monochromator component, the crystal plane lies in
the y-z plane (ie. parallel to the beam). The component also works in
transmission. Reflectivity and transmission files may be used.
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);

When you rotate the component by A1 = asin(Q/2/Ki)*RAD2DEG, do not forget to 
rotate the following components by A2=2*A1 (for 1st order) !

Example: Monochromator_curved(zwidth=0.01, yheight=0.01, gap=0.0005, 
          NH=11, NV=11, mosaich=30.0, mosaicv=30.0, 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 AA (Cu2MnAl)
CoFe         DM=1.771 AA (Co0.92Fe0.08)
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

Input parameters

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
transmit k, T transmission 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 arc minutes Horisontal mosaic FWHM 30.0
mosaicv arc minutes Vertical mosaic FWHM 30.0
r0 1 Maximum reflectivity 0.7
t0 0.3
Q AA-1 Scattering vector 1.8734
RV 0
RH 0
DM 0
mosaic arc minutes sets mosaich=mosaicv 0
width m total width of monochromator 0
height m total height of monochromator 0
verbose 0/1 verbosity level 0

Output parameters

Name Unit Description Default
mos_rms_y  
mos_rms_z  
mos_rms_max  
mono_Q  
SlabWidth  
SlabHeight  
rTable  
tTable  

Links


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

Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Feb 28 2006