Radiation-induced lattice relaxation in [Formula: see text]-Fe[Formula: see text]O[Formula: see text] nanorods

We report radiation-induced lattice relaxation of the [Formula: see text]-Fe[Formula: see text]O[Formula: see text] and its associated alteration of particle morphology. The [Formula: see text]-Fe[Formula: see text]O[Formula: see text] was grown in solution by microwave hydrothermal synthesis technique in which more than half of the synthesized material was nanorods with axis along the (001) direction. Five sets of the synthesized [Formula: see text]-Fe[Formula: see text]O[Formula: see text] samples were irradiated using gamma-ray from [Formula: see text]Co cell with doses of 600 kGy, 700 kGy, 800 kGy, 900 kGy, and 1 MGy. The investigation of the pristine and gamma-irradiated samples was carried out using X-ray powder diffraction, transmission electron microscope, and electron paramagnetic resonance methods. Results showed that continuous alternation of radiation-induced lattice compression and expansion causes lattice relaxation. The morphology of the [Formula: see text]-Fe[Formula: see text]O[Formula: see text] nanorods was found to change with absorbed dose into buckyball-shaped particles in response to the alternation of the compression and expansion strain. The EPR results showed a correlation between distortion in the [Formula: see text]-[Formula: see text] octahedron structure and the relaxation of the lattice. The synthesis, growth, and relaxation are discussed in detail.

Isotope signature and elemental characteristics of subsurface formations around deep-laying coal seams probed by means of atomic and nuclear-based techniques

A systematic investigation on the isotopic and elemental signature, for both stable and radioactive elements, and mineral contents was performed to examine the characteristics of subsurface formations collected at different depths between 3.962 km and 4.115 km around deep-laying coal seams located under the Marmarica plateau in Egypt. Concentrations of major and minor oxides (Na₂O, MgO, Al₂O₃, SiO₂, SO₃, K₂O, CaO, TiO₂, MnO, ΣFeO + Fe₂O₃, SrO, ZrO₂, and BaO) were determined by X-ray fluorescence and dependencies among these concentrations revealed the type and sort of the formations. Organic contents were determined by Fourier Transform infrared spectroscopy to investigate the variation of the CO/CC bonding ratio with depth. Rare earth elements (REE), specifically Y, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu were determined by inductively coupled plasma mass spectrometry while actinoids were detected by the radioactive decay of its daughter nuclei. The results showed a high trapping of REE elements and actinoids in layers above the coal seams which indicates the occurrence of aqueous flow followed by possible sorption in these layers. The mobility of the fluid was investigated using the process radioactive decay series between Ra226 and Ac228 from one side and their daughters from the other side.

Neutron-induced mass shift of tin isotopes recognized using inductively coupled plasma mass spectrometry as an isotopic fingerprint on neutron reactions

The phenomenon of isotope shift in response to neutron irradiation was investigated. The high fission-neutron fluence of 1.44×10¹⁸ cm^-2 from the second Egyptian research reactor (ETRR-2) was used to induce a mass shift in a metallic tin sample. A triple-quadrupole inductively coupled plasma mass spectrometry system was used to analyze the isotope abundances in the mass range from A=111 to A=125. The problem of mass bias due to kinetic fractionation on use of the inductively coupled plasma mass spectrometry system was treated by our calibrating the mass bias with a standard reference tin solution and building a response function. The response function was used to obtain absolute abundances in each mass range instead of isotope ratios. The results show that the mass shifts in the irradiated sample are dependent on the cross section of the neutron capture reaction in the tin isotopes.

The influence of gamma radiation on organic compounds having carbon ring and its application in dosimetry

The formation of highly oxidizing radicals in multifunctional-solid compounds upon irradiation with gamma-ray had been investigated. Five organic compounds having a single carbon ring had been used in the present investigation; these materials are 1-chloro-4-nitrobenzene, 4′-aminoacetophenone, 3′-hydroxyacetophenone, n-anthranilic acid, and triphenylmethane. These material were irradiated using 60Co radiation with different doses between 20 and 100 kGy. Electron spin resonance spectroscopy spotted increases of the resonance absorption having landé factor around 2.0113 ± 0.003 upon irradiation with the increasing of dose. This resonance absorption was related to the formation of long-lived oxygen radicals that were attached to one of the radiation synthesized compounds. The method of infrared absorption spectroscopy emphasized the formation of cyclic and aliphatic hexane in addition to the active oxygen radicals. n-Anthranilic acid was found to be suitable for radiation the dosimetry with long-lasting radiation signature as electron spin and also to determine the exposure dose. The time-lapse infrared and electron spin resonance measurements had been used to tracked the formation of active species within the time-lapsed after the end of exposure; results showed that the dosimetric signature may be used as a tracker for the time when the exposure happens.

Determination of isotopes activity ratio using gamma ray spectroscopy based on neural network model

The uranium isotopes activity-ratio was determined using in-situ γ-ray spectroscopic measurements and an artificial neural network model. The method was developed to use forward-learn multilayer algorithm. Each layer consists of a perceptron, that controls the forward-learn process, and a mean-square-error mapping for the spectral data from the set of fired perceptrons. The set of output parameters should represent a vector of coefficients for double logarithmic polynomial that distinguish the instrumental efficiency. The forward-learn is controlled by a rejection function which is based on an input set Ψ of parameters that tells the neural layer to accept or reject data points. Each layer maps to the next layer by reducing chi-square-difference with the experimental uncertainty as weight. There are two supervised controls to the network, the maximum deviation from interpolated curve and the assumed initial set of rejection parameters (Ψ₀). The model was tested on spectra of known enrichments and gave an excellent agreement with low enriched uranium samples ((1.38 ± 0.14)% and (20 ± 1.55)%). The use of the algorithm on natural uranium ore and association with radium-226 daughters causes increase of uncertainty and deviation of the results from the certified value. The current algorithm provides a practical solution to a wide range of gamma-ray measurement problems encountered for in-situ characterization of uranium-containing materials. These include security, safeguards, fuel assessment, decontamination and decommissioning operations with no collimation or special setup. It is also applicable for large-scale installations.

Development of granular radioactive reference source from 152,154Eu adsorbed on tin tungstate matrix

A reference source with the granular active portion was made using 152,154Eu(III) loaded tin tungstate material. Batch equilibration method was used to investigate the interaction of 152,154Eu(III) radiotracer (10−4 M) in acid solutions on tin(IV) tungstate gel matrix. The sorption behavior of 152,154Eu(III) showed high affinity towards tin(IV) tungstate gel matrix at low pH values. Tin tungstate gel matrix was loaded with 152,154Eu from batch at pH 3. Standardization of the source was done spectroscopically with reference to primary certified set of radioactive sources and with the aid of HPGe detector. Random and true coincidence summing was carried out by following-up coincidence in 152Eu and possible interference between γ lines of 152Eu and 154Eu. The relation between the grain size and the activity of samples was studied. Correction factor for capsule attenuation was applied.

Redox sorption of Ce(III)/Ce(IV) on potassium bismuthate

Potassium bismuthate rods was synthesized in a form of elongated rods in non-aqueous methanol medium. The material morphology and structure were investigated using energy dispersive spectroscopy, scanning electron microscopy, and X-ray diffraction. The effects of annealing temperature on the material morphology and structure were investigated. Sorption kinetic study and ionic selectivity was investigated using batch technique. The sorption of Ce3+ on potassium bismuthate was found to be Ce3+ cation’s ionic state selective process. Results showed that the chemical sorption of Ce3+ ionic state in KBiO3 follows the reduction of Bi5+ to Bi2− as a result of the formation of cerium bismuthide ( Ce 2 3 + Bi 2 − O 2 ) . $({\rm{Ce}}_2^{3 + }{\rm{B}}{{\rm{i}}^{2 - }}{{\rm{O}}_2}).$ The suggested chemo-sorption mechanism includes equilibration parallel processes of the released K+ to form K2CeO2 and Bi2O3 that consumes the original material. The sorption kinetic has two different orders depending on contact time, isotherms fits adequately with Freundlich model and Dubinin-Radushkevich model. The material is considered a candidate for lanthanides radioactivity removal from aqueous media for radioactive waste disposal processes.

Preparation of graphite by thermal annealing of polyacrylamide precursor for adsorption of Cs(I) and Co(II) ions from aqueous solutions

In the present work, graphite nanostructures are prepared by thermolysis of a prepared polyacrylamide gel. The gel was prepared by radical chain polymerization and the synthesis of the nanostructures was done by step annealing at different temperatures. The structural of the prepared materials was studied by X-ray diffraction (XRD). The presence of carboxylic and phenolic functional groups on the graphite surface was confirmed by FT-IR analysis. Batch adsorption experiments were conducted to study the effect of equilibration time, initial metal cation concentration, and solution pH for the removal of Cs(I) and Co(II) from aqueous solutions. Kinetic data of Cs(I) adsorption was found to be well fitted with a pseudo-first-order kinetic model. The obtained isotherm data were correlated with the Langumir and Freundlich isotherm models. The effect of temperature on the equilibrium distribution values was utilized to evaluate the change in the standard thermodynamic quantities of enthalpy (ΔH°), entropy (ΔS°), and Gibbs free energy (ΔG°).

Radioactivity risk associated with the handling of compact fluorescent lamps

The objective of this work is focused in measuring the level of naturally occurring radionuclides in compact fluorescent lamps commonly used in Egypt. The activity concentration of radionuclides in the (238)U and (232)Th decay chains and from (40)K were determined through gamma-ray spectrometry measurements using high-purity germanium in a low-background configuration. It was found that the activity concentrations ranged from 45 to 198 Bq kg(-1) for (238)U, from 30 to 191 Bqkg(-1) for (232)Th and from 419 to 935 Bq kg(-1) for (40)K.

Radiation dose estimation of sand samples collected from different Egyptian beaches

A high pure germanium detector-based gamma-ray spectroscopy low-background counting system was used to determine the levels of natural radioactivity from beach sand samples on the Egyptian coast along the Mediterranean and Red Seas. The activity concentrations of (226)Ra, (232)Th and (40)K were found to lie in the range of 30±11 to 60±14 Bq kg(-1) with a mean of 39±15 Bq kg(-1), 12±3 to 30±14 Bq kg(-1) with a mean of 21±13 Bq kg(-1) and 392±22 to 413±22 Bq kg(-1) with a mean of 402±23 Bq kg(-1), respectively. Radiation hazard indices and annual effective doses were evaluated and compared with the international data. The results indicate that the values obtained fall below the internationally accepted maximum limits and do not pose any significant radiation hazard to individuals in the study area. From these results, a radiological baseline map of Egyptian beaches can be drawn and used as reference information to assess any future alterations in the radioactivity of beach sands due to any changes in the sea sediments.

High gamma-ray dose measurement using nuclear track detector

Three dosimetric properties of poly allyl diglycol carbonate (PADC) and their response to gamma irradiation are put forth. The variation of the optical absorption edge with the received dose can be used as a dosemeter for doses >500 kGy. The variationdielectric function is, to some extent, linear with dose logarithm but has a low precision. The fluorescence emitted from the irradiated PADC upon illumination by the 346-nm UV radiation intensifies the changes in the dielectric properties and shows an excellent dosimetric behaviour in response to gamma ray in both precision and simplicity of procedure. Results showed that this property could be used as a dosimetric properties for measuring doses between 100 Gy and 6 MGy.

Differentiation between earthquake radon anomalies and those arising from nuclear activities

The present work offers a methodology to correlate the earthquake time, magnitude and location based on the behavior of radon concentration. By correlating tectonic events to radon behavior, based on previously published radon data, radon concentration signals can be taken into consideration in decision making. Three correlations between magnitude, time and epicenter distance are presented. The applicability of any one of them depends on the measurement technique. Moreover, a suggested procedure is presented to determine the possible confusion between signals for radon anomalies originating from tectonic failure and those arising from nuclear activities. The suggested method depends on the change observed on the (219)Rn and (222)Rn daughters concentration ratios.

Experimental investigation and nuclear model calculations on proton-induced reactions on highly enriched 114Cd at low energies

The excitation functions of both Cd(p,n)(114m)In114 and Cd(p,2n)(113m)In114 reactions were evaluated experimentally by the stacked-foil technique on highly enriched (114)Cd isotope. Two stacks were irradiated by proton beam with energies 14.7 and 18MeV on the MGC-20 cyclotron at Nuclear Research Center, AEA, Egypt. The present results support the previous measurements. The theoretical interpretations of the measured excitation functions were done by EMPIRE-II (v2.18 Mondovi) code. Compatibility with predictions of hybrid Monte Carlo simulation (HMS) pre-equilibrium mechanism was obtained.