MEASUREMENT OF K-SHELL FLUORESCENCE YIELDS OF SELECTED ELEMENTS FROM CS TO PB USING RADIOISOTOPE X-RAY-FLUORESCENCE

K-shell fluorescence yields were measured for Cs, Sm, Eu, Ho, Ta, W, H g, and Pb using a Ge(Li) detector employing the reflection geometry. T he target atoms were excited by using gamma rays from Co-57 radioactiv e sources of strength 100 mCi. Recently determined values of w(K) for Ba, Ce, Nd, Gd, Dy, Er, and Yb are also tabulated. The experimental re sults are compared with the literature experimental values, theoretica l predictions, and the semiempirical fits.