[Ifeffit] No background subtraction in some cases?

[Bruce Ravel]

Alexander,

DUBBLE certainly does write out a quirky data file.  This was a topic of 
discussion when I was in Ghent earlier this year.  I came up with a solution 
of the sort that Matt mentioned in his email -- a plugin.  It can be found 
here, where its installation is described in detail.

  http://cars9.uchicago.edu/ifeffit/BruceRavel/DubbleBeamline

I tested one of the data files in your zip file against the plugin and it 
seemed to work.  Speak up on the list if you run into any troubles.

I had hoped that the folks who run DUBBLE would point their users at that web 
page.

B



On Friday 02 April 2010 04:22:30 am Alexander Riskin wrote:
> Dear all,
> 
> Recently we've measured samples at the DUBBLE Beamline at ESRF for iron
> and molybdenum (K-edge). After measuring, the DUBBLE software generates
> a .dat file which must then be translated to other files (depending on
> the fact whether transmission or fluorescence is measured) using some
> script in linux. When we try to import some of these transformed files
> (for transmission measured) into Athena however, the program fails to
> subtract a background from mu(E), therefore no k and R-space plots are
> available (see project files MoPEL002 and MoPEL004, the original
> dat.sample files are included in the zip files). Other files however,
> work fine (both transmission and fluorescence measured ones).
> 
> After analyzing the structure of the .dat files, it was discovered which
> columns are the Io an It data and the correct ln(Io/It) could be
> manually generated. This manual procedure yields data sets identical to
> the ones in the dat.sample files, we named them dat.good files. When
> importing these files into Athena, the background subtraction works
> fine. It is the exact same data however...
> 
> Although the problem can be bypassed by processing the data manually,
> the fact that Athena processes some files correctly and others not seems
> very strange to us since they all come from the same beamline. We
> thought it would be interesting to let you all know.
> 
> Thanks for your time and for making such wonderful software,
> Alexander Riskin
> 

-- 

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

 National Institute of Standards and Technology
 Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2
 Building 535A
 Upton NY, 11973

 My homepage:    http://xafs.org/BruceRavel
 EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/