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

[William Bisson]

Dear all,

Daresbury in the UK, produces the raw data in angle of mono steps/angle 
which is then merged, corrected for the monochromator and converted into 
eV and log (It/Io).

Do I take it xmu coloumn refers to log (It/Io) for the data entry into 
Ifeffit?

Regards
William

On Thu, 2 Dec 2004, SCHLEGEL Michel 177447 wrote:

>
>>> But: I'm not aware of any beamline saving data in mono steps.
>>> AFAIK, only the old Lytle data is in this format.  We should not
>>> do anything to encourage this very bad practice. For the record,
>>> it's bad because it assumes you know:  1) steps per degree, 2)
>>> value of steps at angle=0, and 3) lattice spacing of crystal.  If
>>> you don't know all three values, you have nothing.
>>>
>>> So, I agree it would be foolish to try to support every beamline
>>> format, and not likely to be successful.  I also think putting in
>>> the lattice constant for YB66 or polynomial coefficients for the
>>> thermal expansion curve of Si is a similarly doomed.
>>>
>>
>> I think that Matt is right.
>>
>> It is a shame to waste the old Lytle data, but let us not
>> allow that to continue.  If someone really wants the data
>> from that old Lytle data bank then there are inconvenient
>> ways to extract the information, just as it should be.
>
> Would it be advisable - realistic to convert once and for all
> the old Lytle data from the mono step scale to the energy scale?
> (I mean, by wirtue of a well-hacked perl macro).  Is there any
> scientific reason why the old  mono step scale should be kept?
>
>> I second the "Athena test".
>
> As such, spec files with all scans cannot be read by Athena, but
> you can copy out individual "scans" in separate files, for which
> comment lines all start with  "#", the last line given the name
> of the motors and detectors ("energy", "IO"...) and the data is
> then ordered as an array. The promblems are (1) usually all scans
> (table, slits...) are collected in one file, and (2) the column
> ordering varies from file to file (a problem which is already
> wonderfully addressed by Athena, though).
> So maybe a separate splitting macro to take out the do the job
> would be more convenient than asking athena to do all theis work.
> Granted it's tedious, but compared to the time needed to correctly
> extract, interpret & fit the data...
>
> Michel
>
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