Characterization of thin films by X-ray transmission measurements

We have used synchrotron radiation in order to determine the mass densities and the elemental composition of single and multilayered solid films. Soft X-rays were used to measure the spectral transmittance in a certain photon energy range, i.e. between 50 eV and 10 keV, and the local transmission profile at discrete photon energies within this range. To give an example, we present some results obtained for an optical filter which is to be used in the focal plane PN CCD-camera of ESAs XMM (X-ray Multi Mirror) astronomy satellite. Moreover, we established a laboratory set-up for transmittance measurements using the discrete line radiation emitted from a solid target X-ray source. Thus, we are able to control layer thicknesses of thin films produced by vacuum evaporation condensation. We describe the compact X-ray test facility, and give the obtained performance data of the filters.