Non-Specular Scattering from Black Chrome in the Extreme Ultraviolet

An instrument being developed at the Lawrence Livermore National Laboratory is very sensitive to extreme ultraviolet (EUV) radiation. In order to characterize EUV scattering, we are measuring and comparing non-specular intensity reflected from several black chrome plated samples provided by LLNL. The measurements are challenging because the intensity drops off very quickly for non-specular angles making it difficult to see the signal above the background levels of EUV. Doing photon counting with a very low background detector and measuring for extended periods of time, we were able to see above background signals over a large range of non-specular angles. The analysis of our data involves deconvolutions to reconstruct the original image and determine reflectance as a function of angle. We can then reconstruct the non-specular reflectance as a function of scattering angle.