Investigation on L-shell X-ray fluorescence parameters for heavy elements and compounds E. Cengiz ⇑ , E. Tıras ßog ˘lu, V. Aylıkcı, G. Apaydın, N. Küp Aylıkcı Department of Physics, Faculty of Arts and Science, Karadeniz Technical University, 61080 Trabzon, Turkey article info Article history: Received 24 May 2010 In final form 15 August 2010 Available online 20 August 2010 abstract The L-shell X-ray intensity ratios, the production cross-sections, the average L-shell fluorescence yields, the L 3 sub-shell fluorescence yields and the radiative vacancy transfer probabilities from the L 3 sub-shell to the M, N and O sub-shells for heavy elements and their compounds from Ta to Pt were measured. The samples were excited by 59.5 keV c-rays from a 241 Am annular radioactive source. The L X-rays emitted by the samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The exper- imental values were compared with the theoretical and other experimental values for pure elements. Ó 2010 Elsevier B.V. All rights reserved. 1. Introduction When an electron is removed from an atomic shell or sub-shell by photons, electrons or charged-particles having sufficient energy, the reorganization of the atom can take place by different pro- cesses which are radiative transitions and non-radiative transi- tions. The radiative transition is a single electron process in which a vacancy of a single ionized atom is transferred to an outer shell and the released energy is emitted as a fluorescence X-ray. The fluorescence yield of ith shell or sub-shell of an atom, x i , is the probability that a vacancy in that shell or sub-shell is filled by a radiative transition. The non-radiative processes are Auger and Coster–Kronig, and at least two electrons are discussed in these processes. In Auger process, an inner-shell vacancy is filled up by an electron from an outer shell and the excess energy is transferred to another electron either in the same shell or outer shell which is slighter of binding energy. Coster–Kronig (CK) pro- cess is a special Auger process in which an inner-shell vacancy is transferred from one sub-shell to higher sub-shell of the same shell [1]. The vacancy transfer probabilities from L 3 to X (X = M, N and O) is defined as the number of X shells vacancies produced in the de- cay of one L 3 sub-shell vacancy through radiative and non-radia- tive transitions. Sharma et al. [2] investigated the L sub-shell vacancy decay processes for Te, I, Ba, La elements using the Mn Ka X-rays and a low-energy Ge detector. The L i (i = l, a, g, b and c) fluorescence cross-sections were measured by Tirasoglu et al. [3] for the elements in the atomic range 70 6 Z 6 92 using a Si(Li) detector. Hajivaliei et al. [4] calculated the K a 1 ,K a 2 ,K b 1 ,K b 2 and the L l ,L a , L b and L c X-ray production cross-sections and the relative intensity ratios for the elements in the atomic range 60 6 Z 6 70 using 20–25 MeV proton impact. Moreover, Singh et al. [5] measured the L X-ray fluorescence cross-sections and the relative intensities for Hf, Re, Ir, Pt and Pb in the energy range 15–60 keV. Kennedy et al. [6] determined the L sub-shell ionization cross-sections for Ta, W and Pt elements using the experimental X-ray production cross-sections and the available radiative transition probabilities, fluorescence and Coster–Kronig factors. The relative L-shell X-ray intensities of Sm, W, Ir, Au, Hg, Pb and U were measured by Darko and Tetteh [7] using a Cd-109 radioiso- tope source and a Si(Li) detector. Tirasoglu et al. [8] investigated chemical effects on the L i (i = l, a, g, b and c) production cross-sec- tions and the L i /L a (i = l, g, b and c) intensity ratios for Hg, Pb and Bi compounds at 59.5 keV using a Si(Li) detector with resolution 157 eV at 5.96 keV. The relative intensities of some L lines of gold were studied by Jha and Agrawal [9] using the electron beam exci- tation. Furthermore, Kucukonder et al. [10] measured the L X-ray intensity ratios and the production cross-sections for the heavy elements using a 241 Am radiative source and a Si(Li) detector. Apaydın et al. [11] calculated the L-shell average fluorescence yield and the production cross-section for the elements in the atomic range 75 6 Z 6 92 using a 57 Co radioactive source and a Si(Li) detector. Özdemir [12] measured the L sub-shell fluorescence and the Auger yields for the elements from Cs to U using a 241 Am radioactive source of strength 100 mCi and a Si(Li) detector. Fur- thermore, the L sub-shell fluorescence yields were investigated by a lot of researchers [13–17]. Average L and M shell vacancy distributions produced by inner- shell ionization were derived by Rao et al. [18] using the available experimental and theoretical data on the radiative and the Auger transition ratios. Dogan and Ertugrul [19] determined the radiative vacancy transfer probabilities from L 3 to M i ,N i to O i in the atomic range 73 6 Z 6 92. Also, Sharma et al. [20] calculated the radiative vacancy transfer probabilities L i (i = 1, 2 and 3) to M, N and higher shells for the elements from Ir to U. The radiative vacancy transfer 0009-2614/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.cplett.2010.08.020 ⇑ Corresponding author. Fax: +90 462 3253195. E-mail address: erhan_cengiz@ktu.edu.tr (E. Cengiz). Chemical Physics Letters 498 (2010) 107–112 Contents lists available at ScienceDirect Chemical Physics Letters journal homepage: www.elsevier.com/locate/cplett