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L 1 –L 3 Coster–Kronig and L i ( i = 1,2,3) sub‐shell fluorescence yields for Th and U
Author(s) -
Kumar Ajay,
Puri Sanjiv,
Mehta D.,
Garg M. L.,
Singh Nirmal
Publication year - 2002
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.553
Subject(s) - atomic physics , photoionization , ionization , electron shell , l shell , fluorescence , excitation , physics , chemistry , shell (structure) , analytical chemistry (journal) , ion , optics , materials science , composite material , earth's magnetic field , chromatography , quantum mechanics , magnetic field
The L 1 –L 3 Coster–Kronig yield, f 13 , for Th and U was determined using measured intensities of the Lα x‐rays emitted following selective ionization of the L 3 sub‐shell by Mo K x‐rays ( B L 3< E inc. < B L 2) and of those emitted following ionization of the L i ( i = 1,2,3) sub‐shells by the 59.54 keV γ‐rays ( B L 1< E inc. < B K ), where B K/ L iis the K shell/L i sub‐shell ionization threshold of the target element. The measurements were performed using an energy‐dispersive x‐ray fluorescence set up involving an Si(Li) detector and photon sources consisting of an 241 Am radioactive annular source used in (i) the direct excitation mode and (ii) the secondary excitation mode together with the Mo secondary exciter. In addition, the L i ( i = 1,2,3) sub‐shell fluorescence yields (ω i ) for Th and U were deduced using our earlier measured x‐ray fluorescence cross‐sections at incident photon energies in the range 17–60 keV and the theoretical photoionization cross‐sections. The measured f 13 and ω i yields were compared with the available semi‐empirical values and the theoretical values based on relativistic Hartree–Dirac–Slater (RDHS) calculations. Copyright © 2002 John Wiley & Sons, Ltd.