Alignment of L 3 subshell vacancy states created without Coster–Kronig decay through the selective photoionization in 82Pb, 90Th and 92U and effect of external magnetic field
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Alignment of the L 3 (J = 3∕2) subshell vacancy states produced following selective photoionization in the L 3 subshells of the 82Pb, 90Th and 92U elements have been investigated through the angular distribution measurements of the emitted L 3 subshell X-ray lines. The L 3 subshell of 82Pb, 90Th and 92U elements were excited by the incident K X-rays of 37Rb, 41Nb and 42Mo elements from secondary targets, respectively. The K X-rays were obtained from the secondary targets excited by the unpolarized 59.54 keV photons obtained from 241Am point source. The measurements were performed with tri-axial experimental setup over the angular range 90–154∘ by moving the source and keeping the target-detector assembly fixed. The error in the normalization of the L 3 subshell X-rays were removed through the uniform mixing of the reference element into primary element and the simultaneous detection of the L 3 (J = 3∕2) subshell X-rays from primary element and isotropically emitted K (J = 1∕2) X-rays from reference element without disturbing the experimental setup. The incident photon energy (E in ) from secondary target were selected in such way that B L3 < E in < B L2, B Li (i = 1–3) being the binding energy of L i subshell. The selective photoionization leads to reduction in the observed anisotropy due to shifting of unaligned vacancies fromthe L 1 and L 2 (J = 1∕2) subshells to the L 3 subshell (J = 3∕2) through the Coster–Kronig (CK) transitions. The present measurements undoubtedly conclude that anisotropy in the L 3 subshell X-ray emission, if present, is at the most of the order of theoretical evaluated value. The alignment measurements with and without applied external magnetic field (~0.6 T) does not significantly change the emission of the L 3 subshell X-rays.
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