[Ifeffit] Find white line position

Bruce Ravel bravel at bnl.gov
Thu Aug 2 06:41:15 CDT 2018


It's not very sophisticated.

Starting with the "flattened" spectrum (see 
http://bruceravel.github.io/demeter/documents/Athena/bkg/norm.html#the-flattening-algorithm), 
it simply finds the highest point in the spectrum.  Literally just the 
ceiling function.

The flattened spectrum is used rather than the normalized spectrum 
because the curvature of the post-edge (or even the curvature of the 
pre-edge in fluorescence data with a energy dispersive detector) could 
result in other regions being higher in value than the white line.

This is a pretty horrible algorithm.  It is, I think, guaranteed to find 
an obviously wrong point for a metal.  Basically it works for spectra 
with a white line and it will almost certainly fail for spectra without 
a white line.

Use with caution!

HTH,
B


On 08/02/2018 01:28 AM, Hiroshi OJI wrote:
> Dear all,
> 
> I have a question about one of the useful function, "find white line
> position" in Athena.
> 
> Could anyone tell me how Athena find the white line position by this
> function? In other words, I would like to know the algorithm to find the
> white line position in Athena.
> 
> Thank you very much for your help, in advance.
> 
> Best regards,
> 
> Hiroshi Oji
> 
> 


-- 
  Bruce Ravel  ------------------------------------ bravel at bnl.gov

  National Institute of Standards and Technology
  Synchrotron Science Group at NSLS-II
  Lead Beamline Scientist, 06BM (BMM)
  Building 743, Room 114
  Upton NY, 11973

  Homepage:    http://bruceravel.github.io/home/
  Beamline:    https://www.bnl.gov/ps/beamlines/beamline.php?r=6-BM
  Software:    https://github.com/bruceravel
  Demeter:     http://bruceravel.github.io/demeter/


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