Alignment of L3 subshell vacancy states created without Coster–Kronig decay through the selective photoionization in 82Pb, 90Th and 92U and effect of external magnetic field
Alignment of the L3 (J = 3∕2) subshell vacancy states produced following selective photoionization in the L3 subshells of the 82Pb, 90Th and 92U elements have been investigated through the angular distribution measurements of the emitted L3 subshell X-ray lines. The L3 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 L3 subshell X-rays were removed through the uniform mixing of the reference element into primary element and the simultaneous detection of the L3 (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 (Ein) from secondary target were selected in such way that BL3 < Ein < BL2, BLi (i = 1–3) being the binding energy of Li subshell. The selective photoionization leads to reduction in the observed anisotropy due to shifting of unaligned vacancies fromthe L1 and L2 (J = 1∕2) subshells to the L3 subshell (J = 3∕2) through the Coster–Kronig (CK) transitions. The present measurements undoubtedly conclude that anisotropy in the L3 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 L3 subshell X-rays.
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