Proton induced K-shell ionization cross sections for a wide range of elements (4 ≤ Z ≤ 92) within ECPSSR theory and updated experimental data

AbstractWithin 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

Databases of L-shell X-ray intensity ratios for various elements after photon excitation

In this study, a comprehensive dataset of X-ray emission intensity ratios has been compiled, including I L β / I L α , I L γ / I L α , I Ll / I L α , I L γ / I L β , I Ll / I L γ , I Ll / I L β , I L γ 5 / I L α , I L γ 44 ′ / I L α , I L η / I L α , and I L γ 1 / I L α , extracted from literature spanning the years 1971 to 2023, and encompassing 83 research papers. Over this timeframe, a total of 2600 values were collected, comprising some 678 values for I L β / I L α , 696 values for I L γ / I L α , 617 values for I Ll / I L α , along with 132, 132, 89, 60, 70, 71, and 55 data points for I L γ / I L β , I Ll / I L γ , I Ll / I L β , I L γ 5 / I L α , I L γ 44 ′ / I L α , I L η / I L α , and I L γ 1 / I L α , respectively. The reported values are presented with precision up to three to four decimal places, accompanied by their associated uncertainties. Additionally, the tables include calculated weighted averages ( I L i / I L j ) W , uncertainty values ( ε I S D , ε E S D ), combined standard deviations ( z I S D , z E S D ), and average z-scores ( z ¯ I S D , z ¯ E S D ) for these intensity ratios. The data encompasses elements ranging from 39Y to 94Pu when excited by photon bombardment. The assessment of how these experimental data values are distributed according to atomic number indicates extensive coverage across most elements. However, a few isolated instances were identified where either no data or fewer than two data values were available

Hafnium to thorium M-shell X-ray production cross sections by proton impact

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. Keywords: M-shell X-ray production cross sections, ECPSSR theory, Semi-empirical and empirical cross section

Propriétés électriques des oxydes de tantale électrogénérés en milieu aqueux

L'anodisation du tantale en milieu aqueux a été réalisée par chronopotentiométrie. L'exploitation des diagrammes d'admittance permet d'accéder aux propriétés électriques de la couche d'oxyde formée. L'interface électrode/électrolyte peut être modélisée par un circuit équivalent comportant une résistance Rp en parallèle avec une capacité Cp. Cette boucle étant elle-même en série avec une résistance Rs. Les résultats ont montré l'influence du choix de l'électrolyte sur les propriétés électriques des couches d'oxyde formées. Dans un milieu donné, le produit Rp.Cp est constant pour une large gamme d'épaisseurs. La valeur de ce produit constitue un critère de qualité des couches formées ; une valeur élevée indique que le transfert électronique à travers la couche d'oxyde est difficile, donc un caratère plus marqué