Hi Ornel, Alignment is used to compensate for monochromators that do not maintain stable energy calibration between scans. In conventional measurements, you'll generally have several scans that are supposed to be of the same sample under identical conditions, and those scans may need to be aligned with each other. That is not the case for a time series, which is what I think you are saying you have. So in a time series, how do you compensate for any energy drift of the monochromator? If you are recording a simultaneous reference spectrum, you can align the reference spectra to each other. (Athena automatically will shift the sample spectra by the same amount that the reference spectra are shifted.) If you have a time series but don't have a simultaneous reference spectra, it becomes tougher. If you collected a reference spectrum before and after the time series, you could try to interpolate any shift that's seen, although that's dicey; shifts sometimes occur in jumps. But if there's no shift, you're probably OK! If you have a time series and no reference at all, or a reference only before the series, you're out of luck. You're relying then on the assumption of energy stability, which on some beamlines might be OK...but it is best to confirm that by at least measuring a reference before and after. --Scott Calvin Sarah Lawrence College On Oct 14, 2010, at 2:46 AM, ornella smila castro wrote:

Hi everyone,

I am trying to do some data processing with Athena but I am already stuck at the first step. The thing is: I read the worked example section of the "Athena's user guide" and on the example on the iron foil, it is mentioned to calibrate the data at the right energy (until here evrything is fine) but then it is said to align the data. Can anyone explain to me what does "alignment" exactly means, and what is the aim of "aligning the data". The data that I have collected were through a channel through which a solution flow (~200 microliters/hr) so I am not convinced that alignment makes sense.

Many thanks, Ornel