[ Identification | Description | Input parameters | Output parameters | Links ]
Filter_powder
ComponentThis is a general box-shaped powder filter/sample which simulates multiple coherent scattering vectors and absorption (incoherent scattering is modelled as absorption). Crystal structure is specified with an ascii data file. Each line contains seven numbers, separated by white space. 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). Optionally, a number of absorbing blades may be incorporated into the filter - these are X-Z or Y-Z planes evenly spaced along the X or Y axis of the filter which absorb any neutron encountering them. EXAMPLE: You may use, as a filter, something like (5x5x5 cm cube): Filter_powder( ax=2.714, by=2.714, cz=4.405, cc=120, sigma_a = 0.0156, reflections="BeO.lau") and as a sample (1x1x1 cm cube): Filter_powder( ax=3.8186, by=3.8186, cz=11.6777, xmin =-0.005 , xmax = 0.005, ymin = -0.005, ymax = 0.005, zmin = -0.005, zmax = 0.005, XBlades=0, YBlades=0, sigma_a = 0, reflections="YBaCuO.lau") * %BUGS This component is known to produce wrong results but is given in hope somebody will find it useful and fix it.WARNING: This is a contributed Component.
Name | Unit | Description | Default |
---|---|---|---|
reflections | string | File name containing structure factors of reflections | |
xmin | m | Lower x-value of powder sample | -0.05 |
xmax | m | Upper x-value of powder sample | 0.05 |
ymin | m | Lower y-value of powder sample | -0.05 |
ymax | m | Upper y-value of powder sample | 0.05 |
zmin | m | Lower z-value of powder sample | -0.05 |
zmax | m | Upper z-value of powder sample | 0.05 |
ax | AA | ,ay,az : Coordinates of first unit cell vector | 2.714 |
ay | 0 | ||
az | 0 | ||
bx | AA | ,by,bz : Coordinates of second unit cell vector | 0 |
by | 2.714 | ||
bz | 0 | ||
cx | AA | ,cy,cz : Coordinates of third unit cell vector | 0 |
cy | 0 | ||
cz | 4.405 | ||
pack | 1 | Packing factor of powder | 1 |
sigma_a | barns | Absorption cross-section per unit cell at 2200 m/s | 0.0156 |
DW | 1 | Debye-Waller factor of reflection | 1 |
XBlades | 1 | Number of vertical absorbing blades | 2 |
YBlades | 1 | Number of horizontal absorbing blades | 2 |
aa | - | ,bb,cc : unit cell angles alpha, beta and gamma (deg). Then uses norms of vectors a,b and c as lattice parameters. | 90 |
bb | 90 | ||
cc | 0 |
Name | Unit | Description | Default |
---|---|---|---|
XBlade_pos | |||
YBlade_pos | |||
xb | |||
xt | |||
yb | |||
yt | |||
pf_hkl_info |
Filter_powder.comp
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[ Identification | Description | Input parameters | Output parameters | Links ]
Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Thu Mar 4 21:22:11 2010