Frequency Shift of L-Valence Band Spectra of Niobium and Tin in Nb3Sn Compound

Abstract

Soft X-ray L-emission spectra of tin in second order diffraction and of niobium in first order have been studied in pure elements, in oxides, and in intermetallic Nb3Sn compound.The study was done by a newly designed soft X-ray vacuum spectrograph. The curved crystal spectrograph is of the Johann type mounting. The radius of curvature of the bent crystal was 50.8 cm. The essential parts of the instrument are (i) an interchangeable bent crystal holder so that the spectrograph can cover a wide range of energy spectra by using crystals of different d-spacings to obtain highest resolution for the particular wavelength range; (ii) an adjustable Hartmann slit to control the effective width of the bent crystal; (iii) a half-shadow device to take two spectra onto the same film in the lower and upper half of the film; (iv) a sharp edge metal fixed to the Rowland circle to obtain a fiducial mark on the film; (v) a water-cooled rotatable Cu anode target; and (vi) a filament with both translational and rotational freedom to ensure optimum beam focusing.