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[en] Experimental ionization cross sections for K-shell by protons for elements from Be to U available in the literature from 1953 to 1999 are fitted to deduce the empirical K-shell ionization cross sections, 5400 values of cross sections have been collected from various references. The deduced empirical cross sections are compared to the experimental data and to the theoretical values obtained by our research group within the ECPSSR theory and also with the reference ionization cross sections obtained by Paul and Sacher [H. Paul and J. Sacher At. Data. Nucl. Data. Tables 42 (1989) 105]
[en] Theoretical M-shell X-ray production cross sections have been calculated within the ECPSSR model. The semi-empirical cross sections are then deduced by fitting the available experimental data normalized to their corresponding theoretical values for elements with 72≤ Z ≤ 90 by proton in the energy range 0.1-4.0 MeV. Also, an analytical formula has been used to calculate the empirical X-ray production cross sections by direct fitting of the same experimental data, which are found to be universal, both for individual and collective fits. On the other hand, based on the individual fitting which gives the reliable cross sections, we attempt to deduce another new empirical cross sections by assuming that the ratio empirical to ECPSSR of the cross sections is roughly the same for all elements. In addition, our results are presented for selected heavy elements, namely 74W, 79Au and 83Bi, being the most extensively studied. Finally, a comparison is made between the different procedures followed here and the experimental data
[en] Within the individual treatment of the elements from beryllium (4Be) to uranium (92U), the experimental databases are normalized to their corresponding values of the ECPSSR model to deduce the semi-empirical cross sections. These databases rely on the different compilations available in the literature and on the other data extracted from papers published from 1953 till 2010. In the present paper, a fourth order polynomial was used to fit very well the existing normalized database of K-shell ionization cross sections by proton. These procedures generate a new set of parameters for the sake of the quick calculation of the semi-empirical cross sections. A comparison is made between the deduced results and those obtained by using the ECPSSR model where a remarkable discrepancy is observed at low-proton velocity regime especially for the lightest elements
[en] The induced damage in single crystals of Yttrium aluminium garnet (Y3Al5O12) bombarded at GANIL with 561 MeV 51Cr, 466 MeV 128Te, 880 and 957 MeV 208 Pb and 885 MeV 238U ion beams, and at Algiers with reactor neutrons has been studied by optical measurements, profilometry and X-ray diffraction techniques (XRD). The optical absorption spectrum increases with fluence up to saturation level and absorption bands at about 250, 300, and 380 are observed after irradiation with ions and neutrons. X-ray diffraction as well as profilometry measurements show the volume expansion of the sample after irradiation due to the phase transformation from crystalline to amorphous phase. This volume expansion increases as a function of fluence and mean electronic stopping power S e. It reaches saturation at high fluence, but the evolution with S e shows a maximum at 17 keV/nm then it decreases significantly at 31 keV/nm. The track radii deduced from these techniques is seen to increase as a function of mean electronic stopping power from 8 to 17 keV/nm. From the analysis of the results, it is clear that the color centres do not contribute significantly to the swelling in the case of heavier ions with S e larger than 12 keV/nm
[en] The thermal annealing behavior of the Y3Al5O12, CaF2 and LiF single crystals bombarded at Algiers with reactor neutrons has been monitored by optical absorption spectroscopy. The irradiation was performed at about 315 K. On heating samples after irradiation, the optical absorption bands decrease and disappear completely at 873 and 523 K in the case of Y3Al5O12 and CaF2, respectively. Activation energies of 1.2±0.02 and 0.9±0.2 eV are estimated for Y3Al5O12 and CaF2, respectively. On the other hand, the LiF crystal shows a complex annealing behavior. Here, the optical absorption spectrum presents different shapes after each annealing temperature. Four steps are distinguished and discussed on heating samples from 300 to 673 K. Above 673 K, the absorption drops by about 50%; it completely disappears at 773 K
[en] A large database containing about 5400 experimental K-shell ionization cross-sections by protons for elements from Be to U is collected from various sources and compilations available in the literature from 1953 to 1999. The data are divided into groups corresponding to their atomic numbers and fitted separately by analytical functions to deduce empirical K-shell ionization cross-sections. The deduced empirical K-shell ionization cross-sections are presented together with the reference ones obtained by Paul and Sacher for selected elements [H. Paul, J. Sacher, At. Data Nucl. Data Tables 42 (1989) 105]. The two sets of results are compared to the calculations within the ECPSSR theory and discussed.
[en] In this paper, the measured K β /K α intensity ratio values published in the literature from 1980 to 2011 have been reported. The weighted- and unweighted-mean values of the experimental data were fitted by the analytical function to deduce new semiempirical and empirical intensity ratios in the atomic range of 16 Z 92. The semi-empirical intensity ratios were then deduced by fitting the experimental data normalized to their corre- sponding theoretical values and the experimental data were directly fitted to deduce the empirical ones. The results were compared with the other theoretical and experimental values reported in the literature
[en] The induced damage in single crystals of yttrium alumina garnet (Y3Al5O12) bombarded at GANIL with 561 MeV 51Cr, 466 MeV 128Te, and 957 MeV 208 Pb ions, and at Algiers with reactor neutrons has been studied by optical measurements. Optical absorption bands centered at 250, 300 and 380 nm are observed after irradiation with ions and neutrons. The variation of the absorption as a function of fluence and electronic stopping power are presented and discussed. Photoluminescence, excited from 380 nm optical absorption band of this garnet is measured at room temperature. The results show the increase of the emission band width with increasing electronic stopping power. The confrontation of the results obtained with ions and neutrons irradiation confirm the contribution of the energetic heavy ions to point defects production. Furthermore, the existence of an electronic stopping power threshold between 10 and 15 keV/nm for oxygen ions displacements is derived
[en] In this study, empirical K-shell fluorescence yields (ωK) from the available experimental data for elements with 6≤Z≤99 were calculated. The experimental data are fitted using the quantity (ωK/(1-ωK))1/q (where q=3, 3.5 and 4) vs. Z to deduce the empirical fluorescence yields. A comparison is made between the results of the procedures followed here and the literature theoretical and empirical values.
[en] The database, which relies on different compilations available in the literature and on other experimental values extracted from papers published from 1992 till 2010, is used, within the individual treatment of the elements from beryllium (4Be) to uranium (92U), to deduce the empirical cross sections. These experimental data can be presented in a single curve, depending on a scaling law extracted from studies in the most familiar theories of collision (PWBA and BEA). Then, a fourth order polynomial was used to fit very well the existing database of K-shell ionization cross sections by proton. This procedure generates a new set of parameters to calculate empirical cross sections. Following the present procedure, our results are compared with those obtained using the ECPSSR model where a discrepancy is observed in the low-proton energy regime. - Highlights: → We used the experimental data to define the K-shell ionization cross sections. → These values are presented in a single curve used PWBA and BEA theories. → The empirical values are defined for each element separately.