Nuclear Gamma Resonance Research Articles

Short-Range Order in Gallium Solid Solutions in α-Iron

Short-range order in soft magnetic FeGa alloys containing from 3 to 25 at % Ga was studied using nuclear gamma resonance (Mössbauer) spectroscopy. The Mössbauer spectra were analyzed via fitting with subspectra corresponding to different configurations of the neighborhoods of the Fe atoms with Ga in the first and second coordination shells. It has been shown that in samples of alloys containing from 3 to 17 at % gallium, the short-range order is almost independent of the heat treatment conditions (quenching from a paramagnetic state or exposure in a ferromagnetic state) and is characterized by the presence of pairs of Ga atoms in the position of the second neighbors (B2-type clusters). At a Ga content of 17 to 21 at %, the portion of B2 clusters turns out to be significantly higher after quenching than after annealing, which correlates with the observed effect of heat treatment on the magnitude of magnetostriction. As the Ga concentration (21–25 at %) further increases, the observed features in the distribution of Ga atoms indicate the appearance and growth of D03 phase regions.

MOSSBAUER STUDIES OF NATURAL MINERAL RAW MATERIALS OF KAZAKHSTAN FOR BAUXITE-BASED PROPPANTS

The main problem at the oil and gas field is hard-to-recover reserves. The article discusses promising modern methods of increasing oil recovery. The analysis of widely used methods of extraction of hard-to-recover oil and gas reserves is carried out. The Mossbauer studies of the domestic natural mineral raw materials of proppants based on bauxite and aluminum oxides were carried out in order to study the structural and phase features of these materials. Proppants used in hydraulic fracturing to hold cracks play an important role in the oil and gas industry. The Moessbauer method is a powerful tool for studying the structure and electronic state of atoms in materials. It is based on the phenomenon of nuclear gamma resonance absorption and provides information about the chemical environment of the nucleus. In this study, proppants based on bauxite and aluminum oxides were used, which were subjected to a Mossbauer analysis.

Gamma-resonance method for the diagnosis of leukemia

Background. The modern concept of acute leukemia therapy involves stratification of patients into prognostic risk groups and a differentiated approach to treatment based on prognostic factors. However, antitumor treatment, including cytostatics, targeted agents, immunotherapy, cellular technologies, is not always highly effective, especially in patients with a poor prognosis. The development of new high-tech diagnostic methods and the refinement of leukemia prediction models remain an urgent clinical task.Aim. To demonstrate the fundamental capabilities of the nuclear gamma resonance method in the early diagnosis of leukemia.Materials and methods. The blood of 1 healthy man and 5 patients of different genders and ages with leukemia was examined. Gamma-resonance (Mossbauer) spectra of iron nuclei in their blood were analyzed.Results. Significant differences in the parameters of the spectra of 57Fe nuclei in the blood of both healthy men and patients of different genders and ages were revealed.Conclusion. Nuclear gamma-resonance spectroscopy at the atomic-nuclear level reveals the influence of cancer cells on the state of iron nuclei and, consequently, on the state of blood. This method can be used both for early diagnosis of leukemia and for assessing the population of tumor cells after achieving cytological remission in leukemia.

Ближний порядок в "неупорядоченных" твердых растворах алюминия в α-железе

The atomic structure of soft magnetic iron-aluminum alloys is studied by X-ray diffraction and nuclear gamma-resonance spectroscopy. The concentration dependence of the body-centered cubic lattice constant and the short-range order (SRO) parameters in the region of a disordered solid solution is monitored. It is shown that in the concentration range from 3 to 18 at.% Al, the lattice constant increases almost linearly. Discrete decomposition of nuclear gamma resonance spectra makes it possible to determine such SRO parameters as the relative fractions of contributions from coordinations without Al atoms and with one, two, and three Al atoms in the first and second coordination shells. The deviation of the values of these fractions from the average statistical probabilities indicates the presence of a chemical order in the arrangement of atoms. The largest deviations are observed at 12 and 15 at.% Al. Conditions of preliminary heat treatment, such as quenching from the paramagnetic state and holding in the ferromagnetic state, give very similar values of the SRO parameters. The method is characterized by a high resolution in the hyperfine field, while having a rather high sensitivity for determining the intensity of individual contributions.

Short-range order in "disordered" aluminum solid solutions in α-iron

The atomic structure of soft magnetic iron-aluminum alloys is studied by X-ray diffraction and nuclear gamma-resonance spectroscopy. The concentration dependence of the body-centered cubic lattice constant and the short-range order (SRO) parameters in the region of a disordered solid solution is monitored. It is shown that in the concentration range from 3 to 18 at.% Al, the lattice constant increases almost linearly. Discrete decomposition of nuclear gamma resonance spectra makes it possible to determine such SRO parameters as the relative fractions of contributions from coordinations without Al atoms and with one, two, and three Al atoms in the first and second coordination shells. The deviation of the values of these fractions from the average statistical probabilities indicates the presence of a chemical order in the arrangement of atoms. The largest deviations are observed at 12 and 15 at.% Al. Conditions of preliminary heat treatment, such as quenching from the paramagnetic state and holding in the ferromagnetic state, give very similar values of the SRO parameters. The method is characterized by a high resolution in the hyperfine field, while having a rather high sensitivity for determining the intensity of individual contributions Keywords: soft magnetic alloys, disordered Fe-Al solid solution, local ordering, X-ray diffraction, Mossbauer effect, distribution of atoms over coordination shells.

MOSSBAUER AND X-RAY FLUORESCENCE STUDIES OF FLY ASH BASED PROPPANTS

This article discusses the results of the study of proppants obtained from domestic raw materials - bauxite, kaolin and white clay, sand, as well as fly ash by nuclear gamma resonance spectroscopy (the Mossbauer effect) and X-ray fluorescence analysis. The hyperfine structure, electronic states and elemental composition of proppants are given. The results of the study of volatile ash obtained during pulverized coal burning of Ekibastuz, Shubarkul, Karazhyralinsky deposits at thermal power plants are analyzed. According to the results of the studies, various combinations of complex phases and the elemental composition of proppants were determined using Mossbauer spectroscopy and X-ray fluorescence analysis. The Mossbauer measurements were carried out on the MS1104Em spectrometer in the constant acceleration mode with a 57Co source in a chromium matrix at room temperature. The elemental composition of samples of proppants based on fly ash was determined using an energy dispersive X-ray fluorescence spectrometer (RFS) at the EDX-7000 installation of SHIMADZU.

Phase composition and local environment of iron ions in gadolinium-doped iron oxide nanoparticles

FeO ⋅ Fe2O3 ⋅ nH2O, Fe2.95Gd0.05O4 and Fe2.9Gd0.1O4 powders were obtained by chemical precipitation from aqueous solutions. The phase composition and local environment of iron ions in gadolinium-doped iron oxide nanoparticles were studied by X-ray diffraction analysis and nuclear gamma resonance (NGR) spectroscopy. Interpretation of radiographs and NGR spectra of synthesised samples indicates the presence of a superposition of maghemite γ-Fe2O3 and iron hydroxide α-FeOOH in the samples. It was found that under the deposition of powders in the presence of gadolinium nitrate, an increase in the content of iron hydroxide α-FeOOH is observed, which disappears after annealing at 200 °C.

Paramagnetic resonance investigation of mono- and di-manganese-containing systems in biochemistry.

Although not as important as iron, manganese is one of the key transition metal (d block) elements in biochemistry. The role of Mn in photosynthesis is perhaps its "starring role," but has been extensively covered elsewhere and will not be discussed in this chapter. In contrast to iron, for which 57Fe Mӧssbauer effect (nuclear gamma resonance) spectroscopy is available, 55Mn (100% abundant) lacks this ability. Instead, the defining technique for Mn is electron paramagnetic resonance (EPR) spectroscopy, as Mn(II), Mn(IV), and even Mn(III), as well as certain di-Mn systems are generally EPR active. This chapter describes how EPR and its advanced derivatives, electron spin echo envelope modulation (ESEEM) and electron-nuclear/electron-electron double resonance (ENDOR/ELDOR) spectroscopies, provide valuable biochemical information on many Mn-containing systems. These include endogenous Mn in mono- and di-Mn (protein) enzymes as well as brief mention of applications to Mn in non-protein biological systems.

Mössbauer Studies of Narrow Fractions of Fly Ash Formed after Combustion of Ekibastuz Coal.

Nuclear gamma-resonance spectroscopy on 57Fe nuclei, X-ray diffraction, and scanning electron microscopy have been used to study the narrow fractions of fly ash formed after combustion of the Ekibastuz coal. Two groups of samples of magnetic (ferrospheres) and non-magnetic type have been separated by granulometric and magnetic separation. A number of regularities associated with the granules size of fly ash have been established. According to the data of Mössbauer spectroscopy, a decrease in the magnetically ordered contribution has been identified with the growth of the particle size. After magnetic separation, iron in ferrospheres was found mainly in the structure of Fe3O4/γ-Fe2O3 and α-Fe2O3. The dominant phase was Fe3O4 (60–77%), the amount of which decreases with the growth of the grain size. With the growth of the particle size, the ratio of [Fe]tetra/[Fe]octa positions occupancy in Fe3O4 approaches 0.5; the structure of magnetite tends to the stoichiometric composition. α-Fe was found in the composition of ferrospheres, and a mechanism of its formation was proposed. The main components of the non-magnetic fractions of fly ash are mullite, hercynite, and silicate glass.

Charge State Of Impurity Atoms In Semiconductors Studyed By The Emission Mössbauer Spectroscopy Method

When studying the charge state and symmetry of the local environment of impurities, based on the data of nuclear gamma-resonance spectroscopy, it is concluded that the state of impurity atoms depends both on the type of conductivity and on whether these atoms are in the surface layer or in the bulk of semiconductors.

Iron administration in gallium arsenide

Based on the data obtained by nuclear gamma-resonance spectroscopy, it is concluded that the state of impurity atoms depends both on the type of conductivity and on whether these atoms are in the surface layer or in the bulk of semiconductors.

Peculiarities of crystal structure and superfine interactions in alloys Ti-Co-Sn

Alloys with the general formula TiCo2-хSn were produced by way of sintering primary components – pure metals in an argon atmosphere. The alloys were homogenized by annealing in the evacuated quartz vessel at T=1070 K during 500 h. X-ray diffraction analysis confirmed single-phase condition of all samples. Nuclear gamma resonance (NGR) analysis was made at T=295 and 80 K using radiation source BaSn119Sn. It was established, that Sn atoms in samples with x=0.6 and 1.0 are in two crystallographic positions, pyramids (1) and tetrahedrons (2) to which isomer shifts correspond (relative to SnO2 1.52-1.65 mm/s for Sn(1) and 2.99 mm/s for Sn(2). Zeeman splitting for Sn(1) in TiCo2Sn takes place at T=295 and 80 K, and for compositions with x=0.3-1.0 at T=80 K only. For Sn(2) it is noted only in alloy TiCoSn at T=80 K. The conclusion has been made on the reason of formation of effective magnetic fields on non-magnetic tin atoms nuclei.

Macroporous Magnetic Iron Oxides and Their Composites for Liquid-Phase Catalytic Oxidation

A novel synthetic approach is proposed to the production of macroporous magnetic iron oxides and their iron aluminate composites for liquid-phase catalytic oxidation. The materials were prepared by sol–gel synthesis where metal precursors were mixed with a colloidal template solution based on siloxane–acrylate latex. The pore structure and magnetic properties of the composites were studied as functions of temperature and magnetic field. The effects of the heat treatment schedule on the phase composition, porosity, and catalytic properties of the materials were elucidated. The results are supported by scanning electron microscopy, X-ray powder diffraction analysis, nuclear gamma resonance, and low-temperature nitrogen adsorption. The addition of aluminum ions in the course of sol–gel (template) synthesis allows the materials to preserve their pore structure upon high-temperature treatment, thereby improving the catalytic properties and significantly affecting the magnetic characteristics of the resulting magnetic composites.

Ferrimagnetic Nature of Composite Products Based on 1,1'-Diacetylferrocene, ε-Caprolactam, and Taurine

Nuclear gamma resonance (NGR) is used to study powders of externally homogeneous magnetite-like substances that form in the reaction between 1,1'-diacetylferrocene and e-caprolactam or 2-aminoethanesulfonic acid in a relatively low range of temperatures (100–180°C). The powders are shown to consist of magnetite and a ferrocene-containing matrix that contains 1,1'-diacetyleferrocene and an organic nitrogen-containing component. In studying the temperature dependence of the NGR spectra in the range of 295–80 K, it is established that a fast effective exchange of electrons occurs in the samples both internally and between two Fe2+/Fe3+ subsystems, ferrocene/ferricenium and sublattice B of magnetite. As a result, classical mechanisms of electron exchange retardation and the phase ordering of the magnetite structure do not work, and no Verwey transition is observed in the samples.

Influence of Thermomagnetic Treatment on the Damping Properties and Structure of Iron-Based Alloys

The paper describes the influence of thermomagnetic treatment on the parameters of the amplitude dependence of internal friction, the crystal and magneto-crystalline structure of Fe alloys with ferrite structure: Fe – 8%Cr, Fe – 16%Cr, Fe – 19%Cr, Fe – 4%Cr – 2%V, Fe – 3%Cr – 3%Al, and Fe–1.2%C–2% Si–2%Al graphitic steel with graphite and ferrite structure. The thermomagnetic treatment was carried out at a temperature of 450ºС. The structure was studied by means of metallography, X-ray crystal structure analysis, ferromagnetic resonance, and nuclear gamma resonance spectroscopy. It is shown that, the larger the ferrite grain in alloys with ferrite structure is, the greater an increase in internal friction is, in the amplitude range up to approximately the amplitude of its maximum owing to thermomagnetic treatment. The change of the damping properties of graphitic steel caused by thermomagnetic treatment is relatively small, due to a large number of diamagnetic inclusions of graphite and quite fine-grained ferrite matrix. The results of the X-ray crystal structure analysis, the ferromagnetic resonance and nuclear gamma resonance spectroscopy have shown that, in the case of thermomagnetic treatment, diffusion redistribution of atoms of alloying elements, combined with the change of structural anisotropy, takes place in Fe-Cr alloys.

Use of nuclear physics methods for investigation of short-range ordering and defects in iron based simulatuing alloys

The changes of short range ordering and electron density were investigated by means of the nuclear gamma-resonance and the positron annihilation spectroscopies in model alloys containing tungsten, chromium, molybdenum, and vanadium used as dopants. The change of the short-range ordering parameter sign was detected in alloys containing vanadium. Different ordering was also observed in binary and ternary iron alloys. It was shown that dislocations were the main defects in these materials after rolling.

Iterative algorithm for finding the domain of definition of the inverse nuclear gamma resonance problem solution

Iterative algorithm for finding the domain of definition of the inverse nuclear gamma resonance problem solution

Comment on “Observation of nuclear gamma resonance with superconducting tunnel junction detectors” [AIP Advances 6, 025315 (2016)

Comment on “Observation of nuclear gamma resonance with superconducting tunnel junction detectors” [AIP Advances 6, 025315 (2016)

Response to “Comment on ‘Observation of nuclear gamma resonance with superconducting tunnel junction detectors’” [AIP Advances 9, 059101 (2019)

Response to “Comment on ‘Observation of nuclear gamma resonance with superconducting tunnel junction detectors’” [AIP Advances 9, 059101 (2019)

Application of Nuclear Gamma-Resonance Spectroscopy for Determination of Grain-Boundary Diffusion Characteristics and the State of Grain Boundaries

Capabilities of application of Mössbauer spectroscopy for determination of grain-boundary diffusion parameters in coarse-grained and ultrafine-grained materials have been analyzed. Application of this method for revealing of non-equilibrium state of grain boundaries in ultrafine-grained materials obtained by severe plastic deformation is demonstrated.