Alignment Studies for Tungsten Near L3 Sub-Shell Threshold Via Theoretical, Experimental and Empirical Methods

Alignment studies are made for tungsten near L3 sub-shell hreshold using theoretical, experimental and empirical approaches. Experimentally to measure alignment parameter, the angular distribution of L x-rays of tungsten (W-74) is measured in the angular range 0 to 120, where maximum anisotropy is expected. The experimental measurements are performed in XRF laboratories of Raja Ramanna Center for Advanced Technology (RRCAT), Indore, India using a three-dimensional double relection set-up. The weighted average of alignment values with 10% error comes 0.155 0.009. Theoretically, the value of alignment parameter A is calculated using non-relativistic dipole approximation in a point 20 Coulomb potential and is found 0.151 at L3 threshold energy (10.676 keV). For empirical A evaluations, IGELCS interpolated experimental 20 LXRF cross-section *Lg (g = , ) values of Mann et al with 8% reported errors are used along with the radiative decay rates. The comparison among heoretical, experimental and empirical values are similar and values being >0.1 at L3 threshold energy are certainly higher than the 5 to 8 percent uncertainties quoted in earlier experimental results. 

Keywords:- Alignment, cross-section, anisotropy, angular distribution and x-ray luorescence 
Authors:- Ajay Sharma 
Physics Department, Chitkara University, Himachal Pradesh-174103-INDIA 
Raj Mittal 

Nuclear science Laboratories, Physics department, Punjabi University Patiala-147002-INDIA