F.A. Balogun

Bio: F.A. Balogun is an academic researcher from Obafemi Awolowo University. The author has contributed to research in topics: Compton scattering & Thermoluminescence. The author has an hindex of 13, co-authored 31 publications receiving 424 citations. Previous affiliations of F.A. Balogun include University of Sassari.

Distribution of gamma-emitting natural radionuclides in soils and water around nuclear research establishments, Ile-Ife, Nigeria

Abstract: The average concentrations of gamma-emitting natural radionuclides 238U, 232Th and 40K in soils from 13 sampling locations around the nuclear research facilities at the Obafemi Awolowo University (OAU), Ile-Ife, have been measured by means of a well-calibrated high resolution gamma-ray spectrometer. Average data on 0–150 mm and 150–300 mm depth distributions in soils have been obtained. The average total specific activity values of 29.1 ± 4.0, 26.5 ± 3.8 and 131.8 ± 32.8 Bq kg−1 for 238U, 232Th and 40K respectively were obtained. The 137Cs concentration in soil samples was below the limit of detection. Average total specific-activity values of 4.2 ± 1.9 and 3.6 ± 2.1 Bq 1−1 were recorded for 238U and 232Th, respectively, in surface and drinking water.

Compton scattering tomography in soil compaction study

Abstract: Compton scattering imaging technique is investigated as a possible tool in soil density distribution mapping for agricultural purposes. In Compton scattering tomography, the number of photons that had been inelastically scattered from a well-defined volume of a sample is employed as a non-destructive technique to display soil density distribution. Images are also shown, of soil samples, at two closely related densities. Good contrast is recorded between the various inserts and their host matrix. Line scans through the images showed good contrast resolution, shape and edge definition. Spatial resolution could be enhanced by the use of a focussing collimator on the detector. This will also serve to increase the solid angle subtended at the detector by the scattering volume, with a possible reduction in counting time at the same precision level.

Natural radioactivity associated with bituminous coal mining in Nigeria

Abstract: Gamma spectroscopic method was used to determine the natural radioactivity associated with the mining of Nigerian bituminous coal for the purpose of determining the radiological implications of coal mining in the country. The activity concentrations of the radionuclides detected range from 0.20±0.002 to 48.42±5.32 Bq kg −1 . The overall natural radionuclide contribution to the radioactivity of the environment was found to be 404.16±23.44 Bq kg −1 . Of this, coal waste (tailing) alone contributed 49.5% representing the largest contribution. Coal contributed just 5.5%. A comparison of the concentrations obtained in this work for coal with those from other parts of the world indicates that the radioactivity content of the Nigerian bituminous coal is not significantly different. The outdoor and indoor exposure rates in air 1 m above the ground are estimated to be (6.31±1.20)×10 −8 and (7.57±1.20) ×10 −8 Gy h −1 , respectively, for the mining environment. These values compare very well with the global values reported by UNSCEAR: 5×10 −8 and 6×10 −8 Gy h −1 , respectively. The resulting annual effective dose equivalent estimated is (4.49±0.74)×10 −4 Sv yr −1 . This also compares favourably with the global value −4×10 −4 Sv yr −1 , reported by UNSCEAR.

Thermoluminescence properties of barium titanate prepared by solid-state reaction

Abstract: Barium titanate samples prepared through solid-state reaction have been analysed by X-ray diffractometry and thermoluminescence (TL) methods to ascertain their capability for usage as high gamma dose dosimeter for industrial and scientific applications. Exposure to gamma radiation doses from 60 Co was varied between 1 and 9 kGy. The glow curves obtained showed emission peak temperatures lying between 480 and 530 K and were found to be dose dependent. The emission peak temperature for each dose was found to shift towards high temperature as the dose increased indicating a non-first order kinetics, which could be attributed to the creation of deep level defects, caused by the irradiation. The reproducibility tests carried out on the samples showed that the sample preparation as well as the TL response of the barium titanate under gamma irradiation is reproducible and under acceptable limit. The dose response curve showed a good linearity over the dose range examined. The fading characteristics indicated that the TL spectra alter with storage time after irradiation and this has been attributed to the creation of traps of different energy level by irradiation and clustering effect leading to tunneling.

Barium titanate at the nanoscale: controlled synthesis and dielectric and ferroelectric properties

Abstract: The current trend in the miniaturization of electronic devices has driven the investigation into many nanostructured materials. The ferroelectric material barium titanate (BaTiO3) has garnered considerable attention over the past decade owing to its excellent dielectric and ferroelectric properties. This has led to significant progress in synthetic techniques that yield high quality BaTiO3 nanocrystals (NCs) with well-defined morphologies (e.g., nanoparticles, nanorods, nanocubes and nanowires) and controlled crystal phases (e.g., cubic, tetragonal and multi-phase). The ability to produce nanoscale BaTiO3 with controlled properties enables theoretical and experimental studies on the intriguing yet complex dielectric properties of individual BaTiO3 NCs as well as BaTiO3/polymer nanocomposites. Compared with polymer-free individual BaTiO3 NCs, BaTiO3/polymer nanocomposites possess several advantages. The polymeric component enables simple solution processibility, high breakdown strength and light weight for device scalability. The BaTiO3 component enables a high dielectric constant. In this review, we highlight recent advances in the synthesis of high-quality BaTiO3 NCs via a variety of chemical approaches including organometallic, solvothermal/hydrothermal, templating, molten salt, and sol-gel methods. We also summarize the dielectric and ferroelectric properties of individual BaTiO3 NCs and devices based on BaTiO3 NCs via theoretical modeling and experimental piezoresponse force microscopy (PFM) studies. In addition, viable synthetic strategies for novel BaTiO3/polymer nanocomposites and their structure-composition-performance relationship are discussed. Lastly, a perspective on the future direction of nanostructured BaTiO3-based materials is presented.

Influence of Bi2O3/PbO on nuclear shielding characteristics of lead-zinc-tellurite glasses

Abstract: This paper examines the nuclear shielding characteristics for two different lead-zinc-tellurite glass systems with the composition of TeO2–Bi2O3 – ZnO–PbO and TeO2–Na2O – ZnO–PbO coded as series A and series B, respectively. Nuclear shielding features of these glasses have been tested in terms of mass attenuation coefficient (μ/ρ), half value layer (HVL), removal cross section (∑R), exposure buildup factor (EBF), effective atomic number (Zeff), and mean free path (MFP). The μ/ρ values of these systems were generated by Geant4 Monte Carlo simulations over an extended energy range of 0.015–15 MeV. The generated data of μ/ρ were confirmed by XCOM calculations. The results show that the nuclear shielding ability of the lead-zinc-tellurite system increases as Bi2O3 content increases in the glasses of series A and as PbO content increases in the glasses of series B. Moreover, the nuclear shielding ability of the current glass systems have been compared with those of some conventional shielding materials and commercial glasses. It can be concluded that the present lead-zinc-tellurite glass systems could be useful to serve as novel shields for nuclear protection applications.

Physical, structural, optical and gamma ray shielding behavior of (20+x) PbO – 10 BaO – 10 Na2O – 10 MgO – (50-x) B2O3 glasses

Abstract: Glass samples of composition (20 + x) PbO – 10 BaO – 10 Na2O – 10 MgO – (50-x) B2O3 (x = 0, 5, 10, 15 and 20 mol%) have been prepared by melt quenching technique. Density, molar volume, average boron-boron separation, ion concentration, polaron radius, inter-nuclear distance, field strength, oxygen packing density and oxygen molar volume have been determined to study the physical properties of the glasses. The presence of no sharp peak in the XRD spectra confirms the amorphous nature of the glasses. The structural properties of these glasses have been investigated using Fourier Transform Infrared (FTIR) spectroscopic techniques. The direct and indirect band gap energies, refractive index, dielectric constant, optical dielectric constant, molar fraction, reflection loss and metallization have been also investigated from the UV-VIS spectra. Besides, the radiation attenuation features for the prepared glasses have been calculated using XCOM program. The mass attenuation coefficient values and effective atomic numbers are found to increase with an increase in the PbO content. The radiation shielding study revealed that Pb40B30 and Pb20B50 glasses have the lowest and highest values of mean free path and half value layer values. This indicates that the Pb40B30 glass has the highest photon shielding competence.