[Ifeffit] MBACK and Athena

[Bajamundi Cyril]

Chris, 
I measured the spectra of copper foil which gave me
	Cu foil
Then I changed the sample to Sample 1 and did 3 successive scans. 
	Sample1_scan1
	Sample1_scan2
	Sample1_scan3
Thanks.

Cyril
-----Original Message-----
From: ifeffit-bounces at millenia.cars.aps.anl.gov [mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf Of Christopher Patridge
Sent: Friday, March 08, 2013 3:43 PM
To: XAFS Analysis using Ifeffit
Subject: Re: [Ifeffit] MBACK and Athena

Cyril,

Is the copper foil a separate file or is this file imported together with the other scans as a reference channel?

If separate files, then there is not a clear relationship between sample and the foil since these were collected at different times and hence corrections for drift or other gremlins will not be the same.

Chris

********************************
Christopher J. Patridge, PhD
NRC Post Doctoral Research Associate
Naval Research Laboratory
Washington, DC 20375
Cell: 315-529-0501

On 3/8/2013 2:49 AM, Bajamundi Cyril wrote:
> Dear Bruce,
>
> The motivation for the question is that I'm concerned whether the shift in E values after calibration is conserved when the calibrated data has been saved in the .xmu file.
> But thanks to the link you have sent to me and your previous answer in the mailing list archive <<http://www.mail-archive.com/ifeffit@millenia.cars.aps.anl.gov/msg02755.html>> things are a bit clearer now.
> So here's a follow up. I have taken the following scans successively 
> Cu foil
> Sample1_scan1
> Sample1_scan2
> Sample1_scan3
> I then process the data in Athena, to begin I calibrated the Cu foil spectrum, such that the nice orange circle falls at the tabulated value of 8979 eV. This in turn gives some "eshift" value of -0.360. What is the relationship of this eshift to the spectra of  sample 1, should I apply this eshift to the scans for sample 1 as? Definitely I can't apply the E0.
>
> This is still a bit vague  in my mind, even after reading the basic data processing section in the documentation.
> Thank you in advance.
>
> Warm regards,
> Cyril
>
> -----Original Message-----
> From: ifeffit-bounces at millenia.cars.aps.anl.gov 
> [mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf Of Bruce 
> Ravel
> Sent: Thursday, March 07, 2013 3:55 PM
> To: XAFS Analysis using Ifeffit
> Subject: Re: [Ifeffit] MBACK and Athena
>
> On Thursday, March 07, 2013 12:10:26 PM Bajamundi Cyril wrote:
>> 1.     Is this procedure valid? In the sense that no information or features
>> of the spectrum are lost from merge.xmu to merged.xmu.mnor file.
> Do you have some reason to believe that might be happening?  If so, perhaps you could ask a more explicit question.
>
>> 2.     How will the procedure <Calibrate data> affect this procedure?
> Calibration, as it is defined in Athena, is a procedure that changes *both* the E0 and the Eshift values so that a selected point in the spectrum has a selected energy value.
>
>    http://bruceravel.github.com/demeter/aug/process/cal.html
>
> I'm not certain I've answered your question, but I am unclear what is motivating your question.
>
> B
>
>
> --
>   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/ifeffit/Demeter
>
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