The `Powder_filter` component

Incorporating code from Single_crystal, written by KN, December 1999 Box-shaped powder filter

Identification

Author: B. Fortescue
Origin: Based on Be_filter, written by SN Klausen, December 1999,
Date: August 2000
Version: 1.0

Description

This is a general box-shaped powder filter 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 something like:
    xmin =-0.05 , xmax = 0.05, ymin = -0.05, ymax = 0.05,
    zmin = -0.05, zmax = 0.05,
    ax=2.714, ay=0, az=0,
    bx=-1.357, by=2.350, bz=0,
    cx=0, cy=0, cz=4.405,
    pack = 1, sigma_a = 0.0156,
    DW=1, reflections="BeO.ref",
    XBlades=2, YBlades=2
with file BeO.ref.
See also filter.ps (PS doc).

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description
reflections	string	File name containing structure factors of reflections
xmin	m	Lower x-value of powder sample
xmax	m	Upper x-value of powder sample
ymin	m	Lower y-value of powder sample
ymax	m	Upper y-value of powder sample
zmin	m	Lower z-value of powder sample
zmax	m	Upper z-value of powder sample
pack	1	Packing factor of powder
ax
ay
az
bx
by
bz
cx
cy
cz
sigma_a	barns	Absorption cross-section per unit cell at 2200 m/s
DW	1	Debye-Waller factor of reflection
XBlades	1	Number of vertical absorbing blades
YBlades	1	Number of horizontal absorbing blades

Output parameters

None.

The Powder_filter component

Identification

Description

Input parameters

Output parameters

Links

The `Powder_filter` component