Soft X-ray Fresnel-like diffraction from thin films edges by an ultrafast laser plasma source

Summary form only given. We will show how it is possible to perform Fresnel-like diffraction experiments in thin films with this kind of partially coherent compact source. Soft-X radiation is generated by focusing intense laser pulses from a Ti:Sapphire system (50 fs, 800 nm, 120 mJ energy, 10 Hz rep. rate) on a Teflon target down to a 15-mum diameter spot. Soft-X imaging of a damaged 100-nm thick parylene-N film is achieved using a LiF plate as detector; the sample is kept 3 mm away from the plate, whereas the source-sample distance is about 30 cm. A 200-nm thick Ni filter evaporated on a second parylene film is partially overlapped to the sample, stopping in some sample regions the spectral contribution below 350 eV. Images are read offline by fluorescence excitation of color centers generated in the plate; acquisition is performed with a microscope coupled to a low noise CCD camera.