[ Identification | Description | Input parameters | Links ]

The Air Component

Identification

• Site:
• Author: M. B. Nielsen
• Origin: DTU Fysik, NBI
• Date: 05.02.2015

Description

The component simulates air and can be inserted as if it was just some extra sample placed somewhere in the beam line.
The air component is intended to be used in all kinds of setups where air may introduce background.
Code structure in this component is based on the component Saxs_spheres.
The shape of the sample may be a filled box with dimensions
xwidth, yheight, zdepth, a filled cylinder with dimensions radius and yheight,
a filled sphere with radius R.
(NB: As we assume air to be an ideal gas, the volume fractions of the elements in the gas are merely the mole fractional part of the given element.
From this the number density of atoms/molecules is calculated)
The air is dry and assumed to be made of nitrogen, oxygen and argon - all other constituents are neglected.

So far the calculations of the scattering probability (and hence also the weight multiplier) assumes the x-ray source to be unpolarized.
Further the component does not yet account for absorption of x-rays. I.e. absorption is simply omitted, but it may OR may NOT be negligible.
I have not yet looked into this last question, so I can't say if the lack of absorption is a bad thing or if it is allowable.

Example:
COMPONENT air1 = Air(
frac = 0.4, pressure = 50000, temperature = 270,
xwidth = 0.5, yheight = 0.5, zdepth = 1.5, target_index = 1,
focus_xw = 0.5, focus_yh = 0.5)
AT (0, 0, 15) RELATIVE Origin

Input parameters

Links

• Source code for Air.comp.

[ Identification | Description | Input parameters | Links ]