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In this work, an experimental study was conducted on the structural and dielectric properties for nickel-doped Pb1−xNixTiO3 (PNT) perovskite-based ceramics with varying nickel concentrations (x (wt) = 0%, 5%, 10%, 15%, 17%, and 20%). The ceramics were prepared using the hydrothermal process at low temperature, which was compared to the solid-state method. The precursors, in stoichiometric amounts, were placed in an alkaline environment using an autoclave and were heat-treated at 180°C for 24 h. The obtained powders underwent characterization after filtration, washing, and drying. X-ray diffraction analysis with Rietveld refinement highlighted that the powders crystallize in a tetragonal perovskite structure with P4mm space group and transform into a pseudo-cubic structure upon the introduction of nickel cations into the lattice. Scanning electron microscopy was used to observe the material structures at the micro level, revealing a homogeneous grain shape with a decrease in average grain size as the nickel concentration in the compound increased. Raman spectroscopy was employed to study the active phonon modes of the materials. The dielectric properties of the different Pb1−xNixTiO3 compositions were analyzed using dielectric spectroscopy in a temperature range from room temperature to 500°C, and at frequencies ranging from 1 kHz to 1.6 MHz. The results confirm the insertion of nickel cations into the PbTiO3 lattice and highlight the resulting enhanced dielectric constant (εr), transition temperature (TC), and dielectric loss (tan δ). [ABSTRACT FROM AUTHOR]

This work aims to study the dosimetrc parameters of the new 60 Co-source model Co0.A86 used in high dose rate brachytherapy and manufactured by BEBIG (Eckert & Ziegler BEBIG GmbH, Germany). The radial dose function, 2D along&away dose rates and the dose rate constant were investigated in a water phantom. Accordingly, we use the recommendations from the AAPM and ESTRO on dose calculation for high-energy (average energy higher than 50 keV) photon-emitting brachytherapy sources cited in the HEBD working group report. Furthermore, we compared the obtained results with the quoted values in the previous studies. The value of air-kerma strength calculated in this work was 3.030 ± 0.002 UBq -1 . Moreover, the radial dose function and 2D along&away dose rates are evaluated in different tissues and compared with the results obtained in the water and we found a notable difference. To reach the goal we have used MCNPX code for simulation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)