X-ray fluorescence holography of 0.078Â wt% copper in silicon steel

X-ray fluorescence holograms of 0.078 wt% Cu in silicon steel were measured at a synchrotron radiation facility, SPring-8. The present fluorescent X-ray detection system combining a toroidally bent graphite analyzer and an avalanche photodiode enables us to record high-quality holograms by eliminating a strong Fe fluorescence from the sample. The reconstructed atomic image around Cu shows a bcc lattice, which indicates the presence of Cu in an α-Fe lattice.