How to select the required energy resolution

The BACH monochromator has both the entrance and the exit slit. These two elements are important in the determination of the energy resolution of the photon beam delivered by the monochromator. In order to check the resolution the user can utilize the ENERGY Resolution.VI. In this VI it is necessary to set the grating in use, the energy of interest and the opening of the two slits. The VI returns the theoretical (very close to the actual) resolution and the resolving power. These VIs are just calculators and can be used any time!

Then, using the MAIN set the chosen opening of the ENTRANCE SLIT and EXIT SLIT. When you change the enrance slit opening the beamline will take ~30 minutes to stabilize, so you can observe some energy shifts..It would be better not changing the ENTRANCE SLIT very often unless necessary.

The STEP for XPS scans is usually set 1/3 or even a lille bit less than 1/3 of the total resolution. Only a finite number of steps can be choosen because they depend on the pass energy. The acquisition program will set the possible step closer to the value chosen by the user.

The best resolution which can be reached with the ScientaR3000 depends on the slit aperture and the pass energy.
Using the smallest slit (0.2) the analyser resolutions are the following:

PE=2: ~3 meV
PE=10: ~10 meV
PE=20: ~20 meV
PE=50: ~50 meV
PE=100:~100 meV
PE=200:~200  meV

Using 0.8 slit the resolution can be ~2.5 times larger and should be evaluated case by case by measuring the Fermi Level.
Last Updated on Friday, 20 April 2012 11:30