XPS und UPS measurements with the ASTRAIOS analyzer

Today we give you another glimpse into the first results of our brand-new hemispherical electron energy analyzer, the ASTRAIOS 190 2D-CMOS. We present data from a polycrystalline silver sample at room temperature, investigated by means of ultraviolet photoelectron spectroscopy (UPS) and x-ray photoelectron spectroscopy (XPS).­­­

UPS of valence band structure of a silver sample

Angle-integrated UPS is commonly used to measure the occupied valence band density-of-states in order to determine the energetic position of electronic states near the Fermi level. These states govern the chemistry as well as the electrical properties of a material. The Ag sample was illuminated with UV photons with an energy of 21 eV, corresponding to the He I emission line from a SPECS UVS 300 UV source and focused onto the sample using µFOCAL VUV optics. The ASTRAIOS was operated in the wide-angle mode, with a conical acceptance angle of 40 degree. The size of the entrance slit within the lens optics, virtual entrance slit mechanism, is set to 50µm. At room temperature the measured width of the fermi level, 107 meV, is mainly determined by thermal broadening.

XPS data taken with the ASTRAIOS 190

Furthermore, we performed XPS measurements on the same area of the Ag sample with a SPECS focused x-ray monochromator µFOCUS 500, using Al Kα with an energy of 1486.61 eV. In the main panel of the figure below, the Ag 3d3/2 and Ag 3d5/2 lines are plotted for different pass energies of the ASTRAIOS analyzer, ranging from 7.5 to 60 eV. The inset of the figure is from the survey spectrum of the Ag sample measured in medium area mode with a pass energy of 50 eV and shows a smooth transmission of the analyzer in the entire energy range. 

More tests are in progress and we will keep on posting new results regularly. Check our homepage, follow us in our social media channels, or sign in for our newsletter and do not miss any news about the ASTRAIOS 190.


The ASTRAIOS 190 is a revolutionary ARPES analyzer for 2D momentum mapping. It is based on a direct k-mapping single spot shifting lens with a virtual entrance slit for ultimate k- and energy resolved measurements.

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