L₁ fluorescence yield of Yb and Ir

The authors report results concerning the L₁ atomic fluorescence yield, omega ₁, of Yb and Ir, determined by comparing the L X-ray spectrum with the K and gamma spectra, emitted after disintegration of ¹⁷⁰Tm and ¹⁹¹Os, respectively. The experimental results are: Yb, omega ₁=0.131+or-0.013; Ir, omega ₁=0.152+or-0.014. These results are in general agreement with experimental results from other authors in the same Z region, enhancing the need for new theoretical calculations in this region of atomic numbers.