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Lead-free (1−x) BaTiO3 –x BaMg1/3Nb2/3O3 ceramics with x = 0.03, 0.04, 0.05 and 0.06 were prepared by solid-state synthesis. The effects of the Ba(Mg1/3Nb2/3)O3 addition on the phase composition, dielectric and ferroelectric properties, as well as the electromechanical response of the classic ferroelectric BaTiO3 were investigated. The room-temperature X-ray diffraction analyses of all the ceramics revealed a perovskite phase after sintering at 1300 °C with a composition-dependent symmetry. The samples with a lower concentration of Ba(Mg1/3Nb2/3)O3, i.e., x = 0.03 and 0.04, were tetragonal, while the samples with x = 0.05 and 0.06 were found to be cubic. The result is in agreement with the dielectric, ferroelectric and electromechanical properties. With x increasing from 0.03 to 0.06 the temperature of the diffused maximum of the dielectric permittivity decreased from 348 K to 265 K. All the ceramics showed a large electromechanical response: the calculated room-temperature electrostrictive coefficient M 33 of the sample with x = 0.06 was 1.4 · 10−16 m2/V2, which is comparable to the value measured for Pb(Mg1/3Nb2/3)O3 ceramics.

The aim of this article is to determine the resolution of the neutron diffraction system (NDS) installed around the Algerian Es Salam research reactor. By using a new method based on neutron radiography technique we have measured the beam divergence at the exit of Soller Collimator (α2) and hence determine effective collimations. The determination of the adequate resolution of our NDS is performed on experimental results obtained from neutron diffraction patterns for different collimation divergences (α2) and (α3) values obtained from several apertures sizes (S2) and (S3).

This paper reports the effect of neutron irradiation defects on electrical properties of n-type FZ-silicon via the measurements of electrical resistivity. For this purpose, FZ-silicon single crystal was irradiated with neutron fluences ranging between 1.54 × 10 16 and 2.5 × 10 18 cm −2 . The samples irradiated at F 1 = 1.54 × 10 16 cm −2 , F 2 = 7.43 × 10 17 cm −2 and F 3 = 2.5 × 10 18 cm −2 were isochronally annealed from room temperature up to 750 °C. It is found that, for fluences ranging respectively from 1.54 × 10 16 cm −2 to 1.23 × 10 17 cm −2 (stage I) and from 3.09 × 10 17 cm −2 to 2.5 × 10 18 cm −2 (stage II) the resistivity is linearly related to the neutron fluence with two different slopes. The annealing temperature dependence on the electrical resistivity fits well the relation ρ 0 exp(− CT ), where C is a constant depending on the neutron fluence and ρ 0 is approximately equal to the resistivity after irradiation. For annealing temperatures higher than 550 °C, we have found that the resistivity is a decreasing function with respect to the neutron fluence and the transmutation-doped phosphorus atoms become electrically active.

During the last three years a static neutron radiography facility has been designed and installed around one of the horizontal neutron beam channels of the Es-Salam research reactor. In order to extend the field of application of neutron radiography, a development project is actually undertaken. The purpose of this project is the implementation of neutron tomography (NT). The Es-Salam research reactor provides a 10 9 n/cm 2 s thermal neutron beam for the installation of a tomography facility. The aim of this Tomography facility will be to visualize dynamic processes and to implement fast reconstruction methods. A first step in this direction was the design and the realization of an exposition cell, a beam-catcher, a turn table and a neutron beam collimation system. All electronic parts of the detection system will be provided and installed within the frame work of a Technical Cooperation Project (TCP) with the International Atomic Energy Agency (IAEA). This paper describes the estimation procedure of the main design parameters according to the measurement of the beam properties for final tomography station as well as the composition and the performance of the proposed detection system. Moreover, the influence of physical parameters of the irradiation in-pile parts on the image quality and acquisition process is discussed.