Linear polarization of L3 sub-shell X-ray lines for some high-Z elements

In this paper, the degree of polarization of the fluorescent L X-ray lines L-& ell;, L-alpha 1 and L-alpha 2, is studied theoretically with respect to incident energy for some high-Z elements from tungsten to Uranium. The linear polarization for each characteristic line is evolved through alignment parameter assessed by nonrelativistic dipole approximation (NDA) in a point Coulomb potential (A(20)), and accommodating the effect of screening in a screened Coulomb potential (A(20)*) and analytical perturbation theory (A(20)**). The values of degree of linear polarization predicted using alignment parameters (A(20,) A(20)*and A(20)*) are not exactly the same as reported by K & auml;mpfer et al. (Phys Rev A 93:033409, 2016) but the trends are almost the same. Since alignment is model sensitive, therefore, the degree of linear polarization will also be dependent on the theoretical approximation/model used. For L(& ell;)lines, polarization is found to be in the range (12 to 43) %, whereas for the L-alpha 1 line, the ultimate vigorous line of the L-shell emission, the estimated polarization is positive with value range from (+ 2.5 to + 7.5)% and for the L-alpha 2 line the polarization is negative with value range from (- 9.5 to - 27) %. These calculations are in exemplary compromise with the earlier theoretical results and manifest barely a feeble vulnerability of polarization on the vibrancy of the incident radiation. The present polarization trends show resemblance with the results of K & auml;mpfer et al. (2016) and & Ouml;zdemir et al. (Appl Radiat Isotopes 69:991, 2011), although the values are not absolutely matching.