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

Ajay  Sharma; Raj  Mittal

doi:10.15415/jnp.2013.11008

Authors

Ajay Sharma Physics Department, Chitkara University, Himachal Pradesh-174103-INDIA
Raj Mittal Nuclear science Laboratories, Physics department, Punjabi University Patiala-147002-INDIA

DOI:

https://doi.org/10.15415/jnp.2013.11008

Keywords:

Alignment, cross-section, anisotropy, angular distribution and x-ray fluorescence

Abstract

Alignment studies are made for tungsten near L3 sub-shell threshold 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 reflection set-up. The weighted average of alignment values with 10% error comes 0.155 ± 0.009. Theoretically, the value of alignment parameter A20 is calculated using non-relativistic dipole approximation in a point Coulomb potential and is found 0.151 at L3 threshold energy (10.676 keV). For empirical A20 evaluations, IGELCS interpolated experimental LXRF cross-section σ*Lg (g = α, ℓ) values of Mann et al with 8% reported errorsare used along with the radiative decay rates. The comparison among theoretical, 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.

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