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Angular dependence of L 3 x‐ray emission following L 3 sub‐shell photoionization in Pb
Author(s) -
Kumar Ajay,
Garg M. L.,
Puri Sanjiv,
Mehta D.,
Singh Nirmal
Publication year - 2001
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.499
Subject(s) - photoionization , atomic physics , physics , l shell , ionization , photon energy , electron shell , shell (structure) , fluorescence , photon , photoelectric effect , analytical chemistry (journal) , chemistry , optics , ion , materials science , earth's magnetic field , chromatography , quantum mechanics , magnetic field , composite material
Abstract The Ll, Lα and Lβ 2,5,6,7,15 x‐ray fluorescence (XRF) differential cross‐sections in Pb were measured at the 13.6 keV incident photon energy ( E L3 < E inc < E L2 , E L i being the L i sub‐shell binding energy) and in the angular range 90–160°. At this incident photon energy, the L 3 sub‐shell vacancies ( J = 3/2) are produced only due to the direct ionization and the reduction in the observed anisotropy in the emission of the Ll, Lα and Lβ 2,5,6,7,15 x‐rays due to the transfer of unaligned L 1 and L 2 sub‐shell vacancies ( J = 1/2) to the L 3 sub‐shell through Coster–Kronig transitions is eliminated. The measurements were performed using Rb secondary exciter in conjunction with the 241 Am primary exciter as photon source and a Si(Li) detector. The differential cross‐sections for various x‐rays were found to be angle‐independent within experimental error. Integral cross‐sections for the Ll, Lα and Lβ 2,5,6,7,15 x‐rays were also deduced and were found to be in agreement with those evaluated using the most reliable theoretical values of L 3 sub‐shell photoionization cross‐section, fluorescence yield and x‐ray emission rates. Copyright © 2001 John Wiley & Sons, Ltd.