Deviation from the single-particle model in the angular distribution of thorium L3 x rays in proton-impact ionization

作     者：T. Papp J. L. Campbell J. A. Maxwell 

作者机构：Guelph-Waterloo Program for Graduate Work in Physics University of Guelph Guelph Ontario Canada N1G 2W1 

出 版 物：《Physical Review A》 (物理学评论A辑：原子、分子和光学物理学)

年 卷 期：1993年第48卷第4期

页      面：3062-3062页

核心收录：

学科分类：070207[理学-光学] 07[理学] 08[工学] 0803[工学-光学工程] 0702[理学-物理学] 

摘      要：Angular distributions of L3 x-ray transitions, including electric-dipole-forbidden ones, were measured for 1-, 2-, and 3-MeV proton impact on a thorium target, where the excitation and detection systems were cylindrically symmetric. A sophisticated spectrum-analysis technique was applied, where both the Lorentzian broadening of the transitions and the Si(Li) detector response function with various tailing features were taken into account. The anisotropy-parameter ratios are expected to be independent of the ionization process, and to be characteristic of the x-ray transitions in the independent-particle model. The ratios of the anisotropy parameters of the electric-dipole-allowed transitions were in disagreement with this expectation, even when the higher-order multipole contributions were taken into account. These results follow the same trend as earlier angular distribution and angular correlation measurements. Additionally, the electric-dipole-forbidden LtL3M2) and Ls(L3M3) transitions had a P4(cos(θ)) term, which is not expected within the framework of the single-particle-model predictions. Possible causes for this discrepancy are explored.