Re: [Ifeffit] Basic questions about the preliminary data processing in Athena

2018-08-14 Thread Haifeng Li
Hi, Carlo, Thanks for your physical explanation for the calibration. I have another question. I measured the same element at different beamlines. So if I want to compare different samples measured at different beamlines, how should I do for this situation given the possible different calibration

Re: [Ifeffit] Basic questions about the preliminary data processing in Athena

2018-07-27 Thread Robert Gordon
HI Haifeng, Suppose you measure Fe foil three times, and all three scans overlap. They are aligned. But suppose the edge positions are at 7116 eV instead of 7112 eV. The calibration is off. You can adjust to it, but, as Carlo mentioned, it is really an angle correction, not simply a shift in e

Re: [Ifeffit] Basic questions about the preliminary data processing in Athena

2018-07-27 Thread Bruce Ravel
On 07/27/2018 01:32 PM, Haifeng Li wrote: What is the real difference between calibration and alignment? Do they have specific meaning? In Athena, calibration means to determine a value for e0 shift such that a particular point in the data is specified to be a particular energy. Then the val

Re: [Ifeffit] Basic questions about the preliminary data processing in Athena

2018-07-27 Thread Haifeng Li
Hi, Robert, Thanks for your help. One more question. What is the real difference between calibration and alignment? Do they have specific meaning? Thanks, Haifeng On Sun, Jul 22, 2018 at 5:45 PM, Robert Gordon wrote: > Hi Haifeng, > > Here's my take on what you described: > > Two sample to b

Re: [Ifeffit] Basic questions about the preliminary data processing in Athena

2018-07-23 Thread Carlo Segre
The calibration should be done at the beamline with a foil. Once that is done, then you don't really want to change it. Remember that just shifting the energy is not actually the correct way to do a shift. The energy shift is a non-linear function of the angle (Bragg's Law) and so when yo

Re: [Ifeffit] Basic questions about the preliminary data processing in Athena

2018-07-23 Thread Haifeng Li
Hi, Carlo, Thanks for your answer. I may ask you more questions. Why you do not recommend to calibrate the data? Calibration is used to find the E0 and match it to the literature data. What is the real difference between calibration and alignment? Thanks, Haifeng On Sun, Jul 22, 2018 at 5:30 P

Re: [Ifeffit] Basic questions about the preliminary data processing in Athena

2018-07-22 Thread Robert Gordon
Hi Haifeng, Here's my take on what you described: Two sample to be studied at the same edge using the same reference. Three scans on A and three on B are done with simultaneous reference. First: compare the three reference scans for A. If they agree, then compare the data scans. If they also

Re: [Ifeffit] Basic questions about the preliminary data processing in Athena

2018-07-22 Thread Carlo Segre
Hello Haifeng: Personally, I would not calibrate the data but merely align the references of A2 and A3 to the reference of A1 and similarly align B2 and B3 references to that of B1. Once merged, you can then aligh the reference of the merged B samples to that of the merged A samples. If y

[Ifeffit] Basic questions about the preliminary data processing in Athena

2018-07-22 Thread Haifeng Li
Dear ALL, I am a beginner in Athena. Recently I got the spectra and I am confusing about the data calibration and alignment. The manual shows that calibrate the reference data of one scan and align other reference data to that calibrated one. Here I want to show examples. I have two samples A and