The reproducibility of the energy obtained when moving the monochromator was tested on 07.11.2023. The elog post can be found here https://elog-gfa.psi.ch/SF-Photonics/1069
Measuring the N2 absorption line the movement of the line when moving the monochromator was tracked using the PMOS. The results for typical changed about an absorption edge are summarized in the table below. Based on other measurements described in the elog post, the reproducibility depends on the size of the energy step and the direction of the energy change. Smaller energy changes are more reproducible than larger energy changes. It was found that there is a difference in final energy depending on the way the energy is approached (84 meV). However, when the approach is done the same way it is reproducible within ~20 meV for a final change of 6 eV.
| Energy change (eV) | N2 absorption (pixel) | difference (pixel) | difference (meV) |
|---|---|---|---|
| 420 -> 400 -> 406 | 1144.00 | -3.33 | -10.72 |
| 420 -> 400 -> 406 | 1151.00 | 3.67 | 11.79 |
| 420 -> 400 -> 406 | 1147.00 | -0.33 | -1.07 |
| 420 -> 400 -> 406 mean | 1147.33 | 0.00 | |
| 380 -> 400 -> 406 | 1166.00 | -7.50 | -24.12 |
| 380 -> 400 -> 406 | 1175.00 | 1.50 | 4.82 |
| 380 -> 400 -> 406 | 1179.00 | 5.50 | 17.68 |
| 380 -> 400 -> 406 | 1174.00 | 0.50 | 1.61 |
| 380 -> 400 -> 406 mean | 1173.50 | 0.00 | |
| different approaches | -26.17 | -84.14 |