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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