[ Identification | Description | Input parameters | Output parameters | Links ]
Single_crystal
ComponentSingle crystal with mosaic. Delta-D/D option for finite-size effects. Rectangular geometry. Multiple scattering and secondary extinction included. The mosaic may EITHER be specified isotropic by setting the mosaic input parameter, OR anisotropic by setting the mosaic_h, mosaic_v, and mosaic_n parameters. Geometry is a box. Crystal structure is specified with an ascii data file. Each line contains 4 or more numbers, separated by white spaces: h k l ... F2 The first three numbers are the (h,k,l) indices of the reciprocal lattice point, and the last number is the value of the structure factor |F|**2, in barns. The rest of the numbers are not used; the file is in the format output by the Crystallographica program. Lines begining by '#' are read as comments (ignored). Example: Single_crystal(xwidth=0.01, yheight=0.01, zthick=0.01, delta_d_d=1e-4, mosaic = 5, ax = 3.8186, ay = 0, az = 0, bx = 0, by = 3.8843, bz = 0, cx = 0, cy = 0, cz = 11.6777, reflections="YBaCuO.lau") Vanadium incoherent elastic scattering with multiple scattering Single_crystal(xwidth=0.01, yheight=0.01, zthick=0.01, reflections="", absorbtion=5.08, incoherent=4.935, ax=3.0282, by=3.0282, cz=3.0282/2)
Name | Unit | Description | Default |
---|---|---|---|
reflections | string | File name containing structure factors of reflections. Use empty ("") or NULL for incoherent scattering only | |
xwidth | m | Width of crystal | |
yheight | m | Height of crystal | |
zthick | m | Thichness of crystal (no extinction simulated) | |
delta_d_d | 1 | Lattice spacing variance, gaussian RMS | 1e-4 |
mosaic | arc minutes | Crystal mosaic (isotropic), gaussian RMS | -1 |
mosaic_h | arc minutes | Horizontal (rotation around Y) mosaic (anisotropic), gaussian RMS | -1 |
mosaic_v | arc minutes | Vertical (rotation around Z) mosaic (anisotropic), gaussian RMS | -1 |
mosaic_n | arc minutes | Out-of-plane (Rotation around X) mosaic (anisotropic), gaussian RMS | -1 |
ax | 3.8186 | ||
ay | AA | Coordinates of first unit cell vector | 0 |
az | 0 | ||
bx | 0 | ||
by | AA | Coordinates of second unit cell vector | 3.8843 |
bz | 0 | ||
cx | 0 | ||
cy | AA | Coordinates of third unit cell vector | 0 |
cz | 11.6777 | ||
p_transmit | 1 | Monte Carlo probability for neutrons to be transmitted without any scattering. Used to improve statistics from weak reflections | -1 |
absorbtion | barns | Absorbtion cross-section per unit cell at 2200 m/s | 0 |
incoherent | barns | Incoherent scattering cross-section per unit cell | 0 |
aa | deg | . | 0 |
bb | deg | unit cell angles alpha, beta and gamma. Then uses norms of vectors a,b and c as lattice parameters | 0 |
cc | deg | . | 0 |
order | 1 | limit multiple scattering up to given order (0: all, 1: first, 2: second, ...) | 0 |
Name | Unit | Description | Default |
---|---|---|---|
hkl_info | structure | Internal |
Single_crystal.comp
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[ Identification | Description | Input parameters | Output parameters | Links ]
Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Thu Nov 27 09:31:06 2008