Abstract
This work aims to study the alignment properties of electron vacancies produced by proton bombardment in the low-energy region from 100 to 250 keV. The alignment parameter of , and ions after subshell ionization has been investigated experimentally. The typical x-ray spectra are measured for each target at emission angles from to . The angular dependence of differential intensity ratios and is studied as a function of the second-order Legendre polynomial ). Our result demonstrates that and lines exhibit anisotropic emission spatially. The anisotropy parameter is converted to the alignment parameter by considering the Coster-Kronig (CK) correction coefficient and anisotropy coefficient. The results are compared with theoretical prediction within the framework of the semiclassical theory of inner-shell ionization, and good agreement is found in general. A small discrepancy around the inflection point of the alignment parameter is attributed to the atomic parameters employed only for single ionization in the CK correction coefficient.
- Received 23 December 2021
- Revised 9 March 2022
- Accepted 3 May 2022
DOI:https://doi.org/10.1103/PhysRevA.105.052807
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