  Collective X-ray Thomson scattering has become a versatile tool for the
diagnostics of dense plasmas. Assuming homogeneous density and temperature
throughout the target sample, these parameters can be determined directly from
the plasmon dispersion and the ratio of plasmon amplitudes via detailed
balance. In inhomogeneous media, the scattering signal is an average of the
density and temperature dependent scattering cross-section weighted with the
density and temperature profiles. We analyse Thomson scattering spectra in the
XUV range from near solid density hydrogen targets generated by free electron
laser radiation.The influence of plasma inhomogeneities on the scattering
spectrum is investigated by comparing density and temperature averaged
scattering signals to calculations assuming homogeneous targets. We found
discrepancies larger than 10% between the mean electron density and the
effective density as well as between the mean temperature and the effective
temperature.
