A principle of application of β→X internal excitation to the determination of elements in thin metallic films

The principle of application of characteristic X-rays excited directly by β-irradiation in order to determine the concentration of elements in thin metallic films is described. A mathematical expression for evaluation of the excitation yield as a function of the mass number of element and the parameters characterizing the continuous spectrum of β radiation of the applied radionuclide is presented. The results of model investigations on the excitation of the characteristic X-rays in the Fe-Cr and Fe-Ti mixtures by means of 14C β-radiation source have been shown. The model investigations were carried out using powder samples containing the mixture of both elements and a 14C source in the form of BaCO3. A spectrometer with a Si(Li) detector was used for the detection of characteristic X-rays excited by β-irradiation. Results of the diffusion profiles of Cr and Ti in thin steels films are described as an example of the application of this method. 4 refs. (author)