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

In the present investigation, the variation in the external bremsstrahlung (EB) intensity produced due to the beta particles emitted by the ⁹⁰Sr–⁹⁰Y 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. Copyright © 2014 John Wiley & Sons, Ltd.