M-Shell Fluorescence Yields of Bismuth, Lead, Gold, and Osmium

The partial M-shell fluorescence yields of four heavy elements (bismuth, lead, gold, and osmium) have been determined. The method employed was similar to that used for previous measurements of L-shell fluorescence yields. Thin foils of the materials to be studied were exposed to x rays or γ rays which could create vacancies in the L shells of the irradiated materials. The M-shell fluorescence yields were then determined by measuring the coincidence rate between the L and the M x rays observed following the M-shell ionization. It is shown that for the method used here the M-shell fluorescence yield determined is predominantly a combination of the fluorescence yields of the MIV and the MV subshells. The following values were obtained: bismuth, 0.037±{}0.007; lead, 0.032±{}0.006; gold, 0.030±{}0.006; and osmium, 0.016±{}0.003.