Bremsstrahlung in carbon thick targets by proton incidence

The subtraction of the continuum from an X-ray spectrum emitted by proton bombardment is usually carried out by means of a mathematical fitting. The purpose of the present work is to develop an analytical function to model the continuous spectrum generated in a PIXE experiment for different incident beam energies in carbon thick targets. With this purpose, PIXE spectra of a carbon bulk sample were measured in an ion accelerator. The proton beam energies were varied between 0.7 MeV and 2 MeV and the X-rays generated were collected by an energy dispersive spectrometer. The spectra analysis was performed taking into account the main effects underlying the production of the continuous spectrum. Nevertheless, for the cases considered here, it was found that the atomic bremsstrahlung is the most important and other contributions were neglected. The experimental spectra from carbon thick targets were corrected by self-absorption and detector efficiency. The results show that the spectral shape corresponding to thick targets corrected by these effects is similar to the functional behavior presented by thin targets.Fil: Pérez, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Bertol, Ana Paula Lamberti. Universidade Federal do Rio Grande do Sul; BrasilFil: Rodríguez, Tabatha P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Vasconcellos, Marcos Antônio Zen. Universidade Federal do Rio Grande do Sul; BrasilFil: Trincavelli, Jorge Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentin

Experimental determination of the Ag L -subshell x-ray-production cross sections by electron impact through two bulk target methods

The experimental determination of x-ray-production cross sections by electron impact on thick samples is faced in this work, especially focusing on the L subshells of Ag. The integrodifferential method used by An et al. is compared with a recently implemented approach involving the ionization distribution function. The first method has shown good results under suitable conditions, namely, when multiple scattering, bremsstrahlung enhancement, and other secondary effects are negligible. Monte Carlo simulations were performed in order to analyze the influence of these conditions and therefore to extend the validity range of the method by adding a correction factor. The second approach uses the ionization distribution function φ(ρz) to predict the intensity of the emitted photons; this magnitude is assessed by the poema software, previously developed, and it is used to determine correction factors to the cross sections included in the software database. Both approaches were tested by fitting several L-shell spectra measured in a wide interval of incident electron energies, ranging from 4.0 to 25 keV, with an electron microprobe equipped with a wavelength-dispersive spectrometer. The x-ray-production cross sections obtained for each L subshell and the total L x-ray-production cross section were compared with theoretical predictions based on the distorted-wave approach theory and with experimental determinations when available.Fil: Rodríguez, Tabatha P.. Universidad Tecnológica Metropolitana; ChileFil: Sepúlveda, Andrés H.. Universidad Tecnológica Metropolitana; ChileFil: Pérez, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Trincavelli, Jorge Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Castellano, Gustavo Eugenio. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin

L-shell X-ray production cross-sections for Mo by proton impact

Total L and Li subshell X-ray production cross-sections were determined experimentally for Mo by proton impact. The thick-target method was used, and the proton energies ranged from 200 keV to 3 MeV. The recorded X-ray spectra were fitted using novel open software for PIXE semi-quantitative analysis that takes into account X-ray emission, absorption and detection. K-shell X-ray production cross-sections of Ti and Cu samples were used to normalize our results for Mo. The measured Mo L X-ray production cross-sections are in excellent agreement with the predictions of the ECPSSR theory. The sensitivity of the theoretical L shell and Li subshell X-ray production cross-sections to the adopted fluorescence yields and Coster-Kronig coefficients was also studied.Fil: Pérez, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Rodríguez, Tabatha P.. Universidad Tecnológica Metropolitana; ChileFil: Trincavelli, Jorge Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Fernandez Varea, Jose M.. Universidad de Barcelona; EspañaFil: Suarez, Sergio Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentin

L shell X-ray production cross sections for Sr and Mo by proton impact

Total L X-ray production cross sections were measured for Sr and Mo by proton impact. Proton energies ranged from 200 keV to 3 MeV. K shell cross sections of Ti and Cu samples were obtained in order to normalize our results, bearing in mind that for those elements the cross sections have been vastly measured and modeled. The cross sections were obtained using the thick sample method and the results showed general agreement in the range of energies studied. The results obtained here for Sr and Mo are in well agreement with those predicted by the ECPSSR theory in the 500–3000 keV proton energy range. In the case of Sr and proton energies lower than 500 keV, the experimental results do not agree well to the calculated with ECPSSR, differing by values greater than 30%. This discrepancy may be due to an overstimation of the stopping power in oxides or secondary emissions that are not negligible in this energy range. All measured spectra were fitted by a novel open software for PIXE semi-quantitative analysis that take into account several physical phenomena related to X-ray production, absorption and detection.Fil: Pérez, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodriguez Cabello, Tabatha Pamela. Universidad Tecnológica Metropolitana; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Trincavelli, Jorge Carlos. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Suarez, Sergio Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentin