[Ifeffit] Rebinning

Bruce Ravel ravel at phys.washington.edu
Wed Mar 12 15:02:37 CST 2003


Hey folks,

As an interface developer, I have to keep a broad perspective.  It
seems to me that, when Athena gets a rebinning capability, it should
give the user a choice between boxcar and convolution (and whatever
other technique someone makes a reasonable case for), thus I would
want to implement something like what Ken or Shelly wrote as well as
an interface to ifeffit's built-in convolution thingie.

To address one of Matt's points, I reckon I'll put a flag in Athena's
group object that would get set whenever E0 changes.  That way Athena
could automagically rebin the data before background removal for any
data group for which rebinning has been requested.  That combined with
some of Athena's other automation features should make handling large
amounts of qexafs data a breeze.

As for which approach is appropriate, Grant pointed out that
preserving resolution at high k is not completely necessary.  I agree,
but only with the caveat that your measurement is of a single edge.
One could imagine using quick measurement techniques to measure two
different, nearby edges --- perhaps for a dichroism experiment,
perhaps simply to measure two exafs spectra.  In that case, Matt's
concern about boxcar is quite valid.   That's not rocket science, but
it would be easy to forget at the beamline at 3 in the morning ;-)

Regards,
B

P.S.  I really have to insist that everyone (and _especially_ the
digest users) respect netiquette quoting guidelines.  In the last few
days there have been some egregious examples of poor netiquette on our
lovely, little mailing list.  Here's a nice explanation of how to
quote when responding to another person's posting:

  http://earlydues.hispeed.com/ieel/netiquette.htm#quote


	
-- 
 Bruce Ravel  ----------------------------------- ravel at phys.washington.edu
 Code 6134, Building 3, Room 222
 Naval Research Laboratory                          phone: (1) 202 767 5947
 Washington DC 20375, USA                             fax: (1) 202 767 1697

 NRL Synchrotron Radiation Consortium (NRL-SRC)
 Beamlines X11a, X11b, X23b, X24c, U4b
 National Synchrotron Light Source
 Brookhaven National Laboratory, Upton, NY 11973

 My homepage:    http://feff.phys.washington.edu/~ravel 
 EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/



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