Operating the beamline

Setting the photon energy

The photon energy can be set using the following software:

• MSB-MONO Client (manually in Energy window) that commands MSB-MONO Server via TCP/IP;
• Kleopatra (manually using the SetEnergy button or Kleopatra console command) that commands MSB-MONO Server via TCP/IP;
• Beamline (manually using the Set button) that commands Kleopatra via TCP/IP,
• SpecsLab2 (automatically according to Eexc value in the Region Edit window) that commands Kleopatra via RS232;
• KolXPD (manually using the Monochromator control panel) that commands Kleopatra via TCP/IP;
• KolXPD (automatically according to excitation energy value in the region view or the actual position in the running CIS/CFS/NEXAFS/RESPES scan) that commands Kleopatra via TCP/IP.

Photon energies in the range between 40 and 1000 eV can be set freely, without any constraints. Bear in mind that tuning from lower towards higher photon energies is faster than in the opposite direction because of automatic procedure compensating for backlash in this case (the monocromator tunes first to a lower energy than requested in order to arrive always from lower to higher values).

Such backlash compensation may lead to a collision of the optical elements inside the monochromator when tuning to photon energies between 22 and 40 eV! Therefore, when setting energies in this range coming from higher-energy position, always perform this operation in a step-wise manner. E.g. if you require 22 eV photons, tune first to 40 eV, then 35, 30, 25, 24, 23, and then 22 eV. In the increasing direction no caution is needed, as the backlash compensation is not applied.

If you fail and the collision appears, ask the beamline scientist for permission to follow the troubleshooting procedure of unblocking and reference mark searching.

Photon energy error

Due to mechanical design of our monochromator, the error in photon energy setting and reproducibility appears to be similar to multiplicative. Therefore, in the photon energy range up to 50 eV the tuning will be almost perfect with the error below 0.1 eV, at 100 eV below 0.2 eV, at 500 eV and higher not more than several eVs. If your sample is metallic it is a good idea to measure some well defined sharp core levels or Fermi edge in order to have a reasonable energy reference for your data processing. Alternatively, a piece of clean Au foil can be mounted on the sample holder for reference measurements.

If the monochromator is heavily miscalibrated it may have lost its reference marks. They can be found using the procedure described in troubleshooting (ask the beamline scientist for permission first). If it does not help a more complicated monochromator calibration must to be performed.