[Ifeffit] programming error in Hephaestus??

Bruce Ravel bravel at anl.gov
Fri Jun 1 11:13:41 CDT 2007


On Friday 01 June 2007, I.Reitz wrote:

A couple more comments:

> And I have also a question to you: Why do you use 30 eV/e- as ionization
> energy for the gases? Is there a reference for that?

That's not very defensible.  32 eV is probably a better number.  30=32
isn't an awful approximation ;-)

> In addition, don´t we have to take the room temperature into account not
> only the pressure, that means:
> Density(Temperature) = (273,15K/293,15K)*0.003749g/cm^3(at 273,15K)

Of course you do.  Hephaestus is really supposed to be a quick-n-dirty
tool to help you out at the beamline and is targeted at the XAS user.
If you want to absorb aproximately 10 percent of the photons in I0, it
doesn't really seem necessary to make the user measure the ambient
temperature in the hutch.  Or, to put it another way, having controls
for temperature or density or whatever adds complexity to Hephaestus's
interface without adding much value to its intended user.

B


-- 
 Bruce Ravel  ---------------------------------------------- bravel at anl.gov

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