L‐shell Coster–Kronig yields for Pb

Abstract

The f 13 Coster-Kronig yield for Pb was determined as 0.60 ± 0.03 using measured intensities of the La x-rays emitted following selective ionization in the L 3 sub-shell by the Rb K x-rays (B L 3 < E inc. < B L 2 / and of those emitted following ionization in the L i (i = 1, 2, 3) sub-shells by 59.54 keV g-rays (B L 1 < E inc. < B K ), B K and B L i being the K shell and L i sub-shell ionization thresholds of Pb, respectively. The measurements were performed using a 241 Am annular source in direct excitation mode and in secondary excitation mode along with an RbNO 3 secondary exciter as photon sources and an Si (Li) detector. Measurements of the f 12 and f 23 Coster-Kronig yields using similar experimental set-ups are also discussed. It is concluded that the f 12 and f 23 Coster-Kronig yields for 12 elements with 59 ≤ Z ≤ 90 measured by Oz et al. using a similar experimental set-up are not reliable. Copyright  2002 John Wiley & Sons, Ltd.Recently, we reported 5 the L i (i D 1, 2, 3) sub-shell fluorescence yields and L i sub-shell CK yield, f 13 , for Th and U, measured using the selective L i sub-shell photoionization method. In the present work, the measurements were extended to determine the L i sub-shell CK yield, f 13 , for Pb. The f 13 yield was deduced by measuring the intensities of the Pb L˛x-rays produced by 13.68 and 59.54 keV incident photons, which were chosen such that B L 3 < E inc. < B L 2 and B L 1 < E inc. < B K , respectively, where B K and B L i are the K-shell and L i (i D 1, 2, 3) sub-shell ionization thresholds of Pb, respectively, and their values are B K D 88.004 keV, B L 1 D 15.861 keV, B L 2 D 15.200 keV and B L 3 D 13.035 keV. 6 Necessary corrections and limitations of this method for measuring the f 12 and f 23 CK yields are also discussed. During the course of this work, a paper 7 reporting the measured f 12 ,

Li (i = 1, 2, 3) sub‐shell fluorescence yields for 79Au, 80Hg and 81Tl

“…4 The comparison is better presented in Fig. 2 by plotting these values together with the earlier measured values 13,14 for the extended range of elements with 77 Ä Z Ä 92. The measured ω 2 and ω 3 values are in close agreement with the RDHS values 8 and those given by Campbell.…”

“…The geometric arrangements have been described in earlier papers. 14,15 In the direct excitation mode, 59.54 keV -rays from the 241 Am source (emission probability D 35.6 per 100 decays) were used to ionize the L i (i D 1, 2, 3) sub-shells of the target element. In the secondary excitation mode, the 59.54 keV -rays excited the Rb K˛(13.37 keV) and Kˇ(14.98 keV) xrays from the RbCl secondary exciter, which ionized the L 3…”