New method to determine effective atomic number of samples via external bremsstrahlung

Abstract

In the present investigation, the variation in the external bremsstrahlung (EB) intensity produced due to the beta particles emitted by the 90 Sr-90 Y source in the elements Al, Cu, Ag, Sn, and Pb as well as some lead compounds was studied as a function of their masses per unit area. By a suitable regression analysis, two new, handy, and simple expressions for the effective atomic number of the radiator were derived in terms of the measured EB intensity. The novelty of the present method is that these expressions require either two different samples of the same mass per unit area or a single sample of two different masses per unit area for determining the effective atomic number. To check the efficacy of the method, from the measured EB intensity of the group of lead compounds, their effective atomic number was determined by making use of these expressions. The results were found to be in good agreement with the modified atomic number Z mod , calculated by using the theoretical expression of Markowicz and Van Grieken. This establishes the fact that this new method employs simple and very handy expressions which will be convenient particularly in the case of samples which are not abundantly available in nature.

Effective atomic number of some rare earth compounds determined by the study of external bremsstrahlung

“…Over the entire b-spectral range of the radioactive source used. Here typically, n¼2, K is a constant to be determined and S=r is the mass attenuation coefficient defined for the E av b which in the present case is around 908keV (Manjunatha et al, 2014) and rt is the mass per unit area and N ¼ N 0 rt=A is the number of atoms per unit area. N 0 is the Avogadro number and A is the atomic/molecular weight.…”

“…A discussion on the linear variation of S=r with lnZ, is provided by Manjunatha et al (2014). By a proper linear regression analysis, best fit values of lnK, C and D were respectively found to be À44.275 ± 0.168, À0.356 ± 0.038 and 0.792 ± 0.011 after fixing n¼2.…”

“…In the present study, the Z eff was determined by employing the two sample method. This method has been described in a recent paper by the authors (Manjunatha et al, 2014). In this method if I 1 /N 1 and I 2 /N 2 are the EB intensities per atom per cm 2 of the element of known Z and the sample whose Z eff needs to be determined, respectively, then, by a suitable modification of Eq.…”

“…Several investigators have used the EB intensity produced due to radiative interaction of the b-particles with the composite materials to determine their effective atomic number (Kurudirek, 2013;Kurudirek & Celik, 2012;Manjunatha, 2013;Manjunatha & Rudraswamy 2007;Shivaramu, 1990). However efforts to determine the Z eff of rare earth samples are very few in literature.…”

“…In a recent work, (Manjunatha, Sankarshan, and Umesh, 2014) we have shown that the Z eff of such sample could be determined with good accuracy by using a method called "two sample method". In this method, the external bremsstrahlung intensities produced in two targets of the same mass per unit area (one elemental target of known Z and the other sample of interest whose Z eff needs to be determined) are suitably compared to deduce the effective atomic number of the sample of interest.…”