Proceedings NSRP‐19, Dec. 12‐14, 2012 Mamallapuram, Tamil Nadu, India 12 Vacancy Transfer Probability Of Platinum And Lead By Using 2π‐Geometrical Configuration And A Weak γ‐ Source L. Francis Maria Anand 1 , M. T. Rameshan 1 , S. B. Gudennavar 1 , S. G. Bubbly 1 , L. D. Horakeri 2 and B. R. Kerur 3 1 Department of Physics, Christ University, Bangalore-560 029, Karantaka. 2 Department of Physics, S. K. Arts College and H. S. Kotambri Science Institute, Vidyanagar, Hubli-580 031, Karantaka. 3 Department of Physics, Gulburga University, Gulburga-585 106, Karantaka. ABSTRACT The K-L i , K-M radiative and K-L total vacancy transfer probabilities for platinum and lead have been determined from the measured K-shell x-ray intensity ratios. The platinum and lead targets were excited using a weak 57 Co gamma source and the K x-rays were detected using HPGe x-ray detector coupled to 16k MCA employing 2π geometrical configuration. The results are compared with the theoretical values of Scofield (1969) and others experimental data. A good agreement was found between our experimental values and other experimental data. Keywords: K x-ray fluorescence, 2π-geometrical configuration, K x-ray intensity ratios, vacancy transfer probabilities Introduction The study of K x-ray intensity ratio and vacancy transfer probability of elements has been of great importance in various fields like atomic, molecular, nuclear physics and material science. Also the accurate values of vacancy transfer probabilities are required to understand the basic studies of electron capture, internal conversion of gamma rays, photoelectric effect, characteristic x-ray production, radiative and non radiative transition probabilities. Over the years several researchers have measured K x-ray intensity ratios and vacancy transfer probabilities employing variety of methods and detectors [1- 5]. However, these methods involve complicated single and double reflection geometries and strong sources (~10 9 Bq or more). In the present investigation, we have extended the simple 2π geometrical configuration method developed earlier by us [6-9] to measure the K x-ray intensity ratios and vacancy transfer probabilities of platinum and lead. The method uses a weak gamma source to excite the targets and involves sandwiching the target between the detector and source. Because of the wide solid angle, source strength could be of the order of 10 4 Bq. The targets of thickness with 0.75 ≤ β ≤ 0.95 (β, the self attenuation correction factor) are found to be suitable. vacancy transfer probabilities of platinum and lead. The method uses a weak gamma source to excite the targets and involves sandwiching the target between the detector and source. Because of the wide solid angle, source strength could be of the order of 10 Theory Theory The total vacancy transfer probability from the K shell to any of the L i shells, η KLi , is the sum of the radiative vacancy transfer probability, η KLi (R), and the non-radiative vacancy transfer probability, η KLi (A), The total vacancy transfer probability from the K shell to any of the L η KL = η KLi (R) + η KLi (A) (1) η The K-L i radiative vacancy transfer probability is given by The K-L 4 Bq. The targets of thickness with 0.75 ≤ β ≤ 0.95 (β, the self attenuation correction factor) are found to be suitable. i shells, η KLi , is the sum of the radiative vacancy transfer probability, η KLi (R), and the non-radiative vacancy transfer probability, η KLi (A), KL = η KLi (R) + η KLi (A) (1) i radiative vacancy transfer probability is given by (2) where I(KL i ) is the K-L i x-ray intensity, I K (R) is the total intensity of K x-rays and ω K is the K shell fluorescence yield. Since K to L 1 radiative transition is forbidden, we have only K-L 2 and K-L 3 transitions and the corresponding radiative vacancy transfer probabilities [10] are given by (3) (4) The probability for the radiative transfer of a vacancy from K to M shell is defined as the average number of M shell vacancies created per K shell vacancy decay through a radiative K-M transition and is given by (5) where . The total vacancy transfer probability, η KL can be expressed in terms of K shell fluorescence yield, ω K and the K x-ray intensity ratio I(K β )/I(K α ) [11] as (6) The K shell x-ray intensity ratios are the ratios of the intensities of K α2 to K α1 , K β1 to K α1 and K β to K α . The ratio of the intensity of the characteristic x-ray of type i to type j is given by (7) where i = K α2 , K β1 , K β and j = K α1 , K α1 , K α , for the intensity ratios , and , and are the measured K x-ray intensities of type i and j respectively, ε i and ε j are the efficiencies of the detector for fluorescence K x-ray of type i and j respectively, β i and β j are the self-absorption correction factors for the K x-ray of type i and type j respectively in the target material and are calculated using the eqn. (8), exp(- μ xiw t w ) and exp(-μ xjw t w ) are the window attenuation correction factors for fluorescence x-rays of type i and j respectively; here μ xiw and μ xjw are the mass attenuation