https://doi.org/10.1140/epjd/e2013-30356-7
Regular Article
Alignment of L3 subshell vacancy states in Au, Bi, Th and U following photoionisation and effect of external magnetic field
1 Department of Physics, Panjab University, 160 014 Chandigarh, India
2 Department of Physics, College of Science, Al-Mustansirya University, 47162 Baghdad, Iraq
3 Department of Applied Sciences, Chitkara University, 140 401 Rajpura, India
a
e-mail: sanjeevkchandel@gmail.com
Received: 7 June 2012
Received in final form: 8 February 2013
Published online: 7 May 2013
Alignment of the L3 (J = 3 / 2) subshell vacancy states in the Au, Bi, Th and U elements following photoinisation have been investigated through angular distribution measurements of subsequently emitted L3 subshell X-rays. The 59.54 keV unpolarised γ-rays from the 241Am radioactive point-source were used to ionize the target and the subsequently emitted L X-rays were measured using an HPGe detector. The improved experimental procedure along with correct evaluation scheme permits straight-forward method for investigating anisotropy in photo-excited L X-ray emission. The efficiency of the detector and the absorption correction for the emitted L X-rays in the target remain fairly constant as the target-detector assemblage remains undisturbed in the present measurements at various angles. Isotropically emitted L1 subshell (J = 1 / 2) X-rays measured simultaneously were used to normalize the L X-ray spectra taken at different emission angles. The present measurements clearly support small theoretical predicted values of the alignment parameter; however, it is difficult to infer regarding the predicted anisotropic trends. The angular distribution measurements for the L3 subshell X-ray emission were also performed by placing the target in magnetic field ∼ 0.6 T. The earlier reported large anisotropy in angular distribution of the emitted L3 subshell X-rays and significant effect of external magnetic field on the angular distribution are ruled out.
Key words: Atomic Physics
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2013
