Mass absorption coefficient in the 200-800 eV region of sp carbon atoms measured using self-standing polyethylene thin films.

To experimentally determine the mass absorption coefficient (μ) of a sp-carbon (C) atom in the soft X-ray region, soft X-ray absorption spectra (XAS) in the 200-800 eV and C K regions of 200-nm-thick self-standing polyethylene (PE) films were measured in the transmission and total electron yield (TEY) modes. PE films were prepared by a spin-coating method. Their experimentally measured thickness and density are 200 nm and 0.920 g/cm, respectively. Soft X-ray absorption measurements were performed in beamline BL-6.3.2 at the Advanced Light Source. Although surface oxygen can be slightly observed in the O K and C K regions in TEY-XAS, it cannot be observed in absorbance-XAS. The absorbance-XAS profiles agree well with the calculated profiles, except in the C K threshold. Hence, it can be confirmed that the absorption-XAS measurements are achieved. From the absorbance, μ of sp-C in PE is 7 × 10 cm/g near 288 eV and 294 eV.