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

The Filter_gen Component

Identification

• Author: EF (from Flux_adapter)
• Origin: ILL
• Date: Dec, 15th, 2002
• Version: 1.5

Description

This component changes the neutron flux (weight) in order to match
a reference table in a file.
Typically you may set the neutron flux (source-like), or multiply it
using a transmission table (filter-like).
The component may be placed after a source, in order to e.g.
simulate a real source from a reference table, or used as a filter (BeO)
, or as a window (Al). The behaviour of the component is
specified using the 'options' parameter, or from the file itself (see below)
If the thickness for the transmission data file D was t0, and a different
thickness t1 would be required, then the resulting transmission is:
  D^(t1/t0).
You may use the 'thickness' and 'scaling' parameter for that purpose.

File format:
This file may be of any 2-columns free format (k[Angs-1],p), (omega[meV],p)
and (lambda[Angs],p) where p is the weight. The type of the file may be
written explicitely in the file, as a comment, or using the 'options'
parameter.
Non mumerical content in file is treated as comment (e.g. lines starting
with '#' character).
A table rebinning and linear interpolation are performed.

EXAMPLE : in order to simulate a PG filter, using the lib/data/HOPG.trm file
     Filter_gen(xmin = -0.1, xmax = 0.1,
      ymin = -0.1, ymax = 0.1,
      file="HOPG.trm")

in this file, the comment line
    # wavevector multiply
sets the behaviour of the component. One may as well have used
    options="wavevector multiply"
in the component instance parameters.

Input parameters

Output parameters

Links

• Source code for Filter_gen.comp.
• HOPG.trm file as an example.

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