Dear Maurizio, Matt,
I just checked why some older files from my beamline work correctly
while the newer ones are not identified as xas data. After your
explanation the reason is quite simple. In the old format the last line
of the header was
#enc_energy mono_energy mono_bragg Step_Pos mono_X1vert....
After rewriting major parts of the beamline software among other things
the last line of the header changed to:
# E_enc E_step Bragg_enc Bragg_step...
Once I replace E_enc with something like energy_enc or enc_energy the
data is correctly identified as xas data.
So, the easiest solution for data taken at P65 is that I will change the
header in the data file so that the first column has a name that
contains "energy". I think i remember that Athena was looking for the
first column were the value of every point n+1 is larger than the value
of point n. it then usually correctly identified that column to be the
energy axis. However, I think labeling the columns correctly, that means
following common accepted conventions, is much easier than programming a
bunch of complicated fail safe energy axis recognising procedures.
Cheers,
Edmund
On 28.02.23 18:16, Matt Newville wrote:
Hi Siebe,
Just to agree with Edmund and Mauro: selecting "energy" and changing
data type from "raw" to "XAS" should help. But, you would have to do
this for every file, which is not ideal.
The file reader is trying to guess whether data is in energy (and if
so, what units are used) and whether it is really XAS data or some
other kind of data. I suspect that it is defaulting to "raw" because
the energy column is not labeled "energy", but "col1" -- it sort of
looks like the reader is not doing a good job of guessing what the
columns mean.
Posting a file would help diagnose why it is guessing wrong. The file
reading does try to guess what beamline a data file came from, so if
you send a file, maybe we can add enough hints for files from that
beamline to work more reliably.
On Tue, Feb 28, 2023 at 6:37 AM Welter, Edmund <edmund.wel...@desy.de>
wrote:
Dear Siebe,
did you try to change the data type from "raw" to XAS. If you
click on the small arrow on the right you should have the choice
between xas and raw. On my computer that works and after that I
can choose the unit for the X-axis. For some reason "raw" seems to
be the preset choice. Maybe Matt could change that, I fell into
this trap several times.
Cheers,
Edmund
------------------------------------------------------------------------
*From: *"van der Veer, Siebe" <s.van.der.v...@rug.nl>
*To: *"XAFS Analysis using Ifeffit"
<ifeffit@millenia.cars.aps.anl.gov>
*Sent: *Tuesday, 28 February, 2023 13:16:18
*Subject: *[Ifeffit] XAS viewer unit detection during data reading
Dear all,
I am not sure if this mailing list is the correct medium for this
question. Apologies, if not.
I am looking to import files in XAS viewer, which worked fine in
ATHENA, but in XAS viewer the correct units of the data are not
detected and I cannot manually change them. I can get a plot of
the data, but the data is not recognized by the software as XAS
data, i.e. a lot of plotting/conversion options do not show.
I hope the following screenshots provide sufficient information to
illustrate my issue.
Reading in a .dat file of fluorescence data. I can't change the
units in the marked area.
image.png
The data can be read into the XAS viewer, but I don't have the
regular plotting options in these dropdown menus.
image.png
Any advice would be much appreciated.
Kind regards,
--
*Siebe van der Veer* | *PhD student*
Nanostructures of Functional Oxides | Zernike Institute for
Advanced Materials
University of Groningen | Nijenborgh 4, 9747 AG Groningen | The
Netherlands
Email: s.van.der.v...@rug.nl|
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--
--Matt Newville <newville at cars.uchicago.edu
<http://cars.uchicago.edu>> 630-327-7411
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