[Ifeffit] Re: Ifeffit Digest, Vol 22, Issue 1

[Bruce Ravel]

Hi,

There are three aspects to this morning's thread that I'll comment on.

(1)  I won't disagree that XAS data should be presented to the
     beamline user in the form of signal as a function of energy.
     That should be considered a standard format for data
     presentation.  That said, it is, apparently, less clear to me
     than to some others what Athena should and shouldn't do.  Athena
     already has utilities for e.g. converting from keV to eV (a
     fairly trivial chore) and converting dispersive data measured as
     a function of pixel position into data as a function of energy (a
     fairly tricky chore).  It's not clear to me that encoder to
     energy conversion is so very different from those.

     It'll be easy enough to ignore, if it really bugs you ;-)

(2)  I am uncomfortable with the phrase "the Athena test".  I cannot
     comfortably be a part of any discussion of file standardization
     that has such an obvious conflict of interest built in from the
     get-go.

(3)  Supporting data harvested from SPEC files has long been on my
     list of things to do.  A good, object-oriented interface to spec
     files built with perl would take a week or two of solid work to
     build and test properly.  I am aware of many beamlines (a few at
     the ESRF for example, as well as any crystallography beamline
     that wants to pop off a quick absorption scan) that use SPEC, so
     that would be a useful thing to have -- not just for Athena but
     for anything in perl that wants to play with SPEC files.  (A
     quick google search turns up nothing of the sort, sadly.)

     The issue of incompletely documented columns is, as Matt pointed
     out, a real one with SPEC files.  However, it's not a problem
     unique to SPEC files.  DND-CAT, for instance, produces files that
     have that problem in spades.  (Well... the ones that Dave Barton
     keeps sending to me do...!)  Dealing with non-obvious files is
     the reason that Athena's column-selection dialog replots the data
     every time you click one of the column buttons.  This allows you
     to poke at an unclear file until you find some columns that make
     sense.

B

-- 
 Bruce Ravel  ----------------------------------- ravel at phys.washington.edu
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 NRL Synchrotron Radiation Consortium (NRL-SRC)
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 National Synchrotron Light Source
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