Natural Zirconium Research Articles

The total neutron production from the alpha induced reaction on natural zirconium

The total neutron production from the alpha induced reaction on natural zirconium

Study of photonuclear reactions with the alpha particles’ emission on zirconium, niobium, and molybdenum

Photonuclear reactions with the emission of protons and alpha particles have been little studied experimentally since their cross-sections are much smaller than those of the (γ, n) channel due to the Coulomb barrier. However, the study of such reactions is of great applied interest to producing medical isotopes. Besides, experimental data on photonuclear reactions with the emission of charged particles for nuclei with Z = 40, 41, 42 open up great opportunities for learning the role of magic numbers. In the presented article, we obtained the weighted average yields of (γ, αn)-reactions for natural zirconium, niobium, and molybdenum at bremsstrahlung γ-quanta of 20 MeV boundary energy for the first time. A significant effect of a closed N = 50 shell was established on the reaction yield with the emission of alpha particles. Our research shows that the semi-direct mechanism for (γ, αn) reactions dominates in the energy range below the Coulomb barrier. As a result, we can note the prospects of applying (γ, αn)-reaction on 94Mo to produce the 89Zr promise medical radionuclide isotope using electron accelerators.

Cross sections for natZr(n,xn)88Zr and natZr(n,xn)89Zr reactions at neutron energies from 29.4 to 42 MeV

Cross sections of natZr(n,xn)88Zr and natZr(n,xn)89Zr were measured at six neutron energies in the energy range of 29.4–42 MeV by irradiating natural zirconium (natZr) samples. The neutrons were produced via 9Be(p,n)9B reaction induced by bombarding a 0.25 mm thick beryllium target with 35, 40, and 45 MeV protons. The neutron spectrum produced at each proton energy was simulated by using the PHITS code. Two neutron peaks were observed in the simulated spectra for each proton energy. By using the estimated activity ratio factor for each neutron peak and experimentally measured γ-ray activities of 89Zr and 88Zr, the cross sections of natZr(n,xn)89Zr and natZr(n,xn)88Zr reactions were obtained, respectively. These experimentally measured cross sections were compared with the cross sections estimated by the TALYS-1.95 calculations and those from the EAF library. For natural zirconium, these cross sections are reported here for the first time in the neutron energy range of 29.4–42 MeV.

Synthesis, Characterization and Activity Test of Natural Zirconium Zeolite (Zr-ZA) Catalyst in The Esterification Reaction of Glycerol with Acetic Acid Anhydride

Synthesis of Zr-ZA catalyst used as catalyst for esterification reaction of glycerol with acetic acid anhydrous has been done. Catalysts are characterized using an infrared spectrophotometer, X-ray diffraction, and measurement of surface acidity, while reaction products are characterized using a gas chromatography-mass spectrometer. Effect of catalyst acidity, reaction time and re-addition of acetic acid anhydrous studied by glycerol conversion and selectivity value of triacetin were yielded. Infra-red spectrophotometer and X-ray diffraction analysis of the catalyst showed that the synthesized catalyst was zirconium zeolite (Zr-ZA), while esterification analysis using a gas chromatography-mass spectrometer showed a triacetin product.

The influence of hafnium impurities on the electrochemical performance of tantalum substituted Li7La3Zr2O12 solid electrolytes

Garnet-based Li7La3Zr2O12 (LLZO) is considered one of the most promising oxide-ceramic solid electrolyte materials for inorganic all-solid-state batteries. Dopants and substituents like Al, Ta, Nb, Ga, and W were shown to have a high impact on the total ionic conductivity, increasing it from 10−6 S/cm up to 10−3 S/cm. However, natural zirconium sources always contain a small amount of hafnium which could also act as dopant, but the separation of these two elements is complicated and expensive. In this work, we investigate the influence of various Hf-impurity concentrations on the performance of tantalum-doped LLZO. We synthesised Li6.45Al0.05La3Zr1.6−xHfxTa0.4O12 (LLZHO with x = 0 – 1.6) via conventional solid-state synthesis and have demonstrated that up to x = 0.1, hafnium impurities do not have a significant impact on the performance of the material. Above this concentration, the Li-ion conductivity is steadily reduced to around 70% when zirconium is fully substituted by hafnium resulting in Li6.45Al0.05La3Hf1.6Ta0.4O12. As the purity of Zr precursors has a great impact on their price, these findings can help to reduce the price of LLZO in general, as lower grade zirconium can be used in industrial scale applications.

Excitation function for the production of 96Nb in the natZr(p,x) reaction

Abstract. We have measured the excitation function for the production of 96Nb in proton induced reaction on natural zirconium in the energy range of 10.58 MeV to 43.61 MeV. The measurement was performed using a stacked-foil activation method combined with off-line γ-ray spectrometry. The stack containing Zr samples, Cu monitors, and several energy degraders was irradiated at the MC-50 Cyclotron of the Korea Institute of Radiological and Medical Sciences (KIRAM), Korea. The cross section of the natZr(p,x)96Nb reaction was extracted from the measured activity of reaction product using an HPGe γ-ray detector. The energy of the proton beam along the stacked foil was calculated using the code SRIM-2013. The proton beam flux was determined via the natCu(p,x)62Zn and natCu(p,x)65Zn monitoring reactions. The measured cross sections of the natZr(p,x)96Nb reaction as a function of the proton energy are compared with the literature data as well as with the theoretical predictions using the TALYS-1.95 nuclear model code and the TENDL-2019 nuclear data library.

The Zr-Doped CaO CO2 Sorbent Fabricated by Wet High-Energy Milling

We fabricated the Zr-doped CaO sorbent for high-temperature CO2 capture by the wet high-energy co-milling of calcium carbonate and natural zirconium dioxide (baddeleyite) for the first time. The morphology of the material was examined by scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. Its CO2 uptake capacity was determined using thermogravimetric analysis. After 50 carbonation–calcination cycles, the Zr-doped CaO sorbent characterized by a high enough CO2 uptake capacity of 8.6 mmol/g and unchanged microstructure due to CaZrO3 nanoparticles uniformly distributed in the CaO matrix to prevent CaCO3 sintering under carbonation. The proposed easy-to-implement CaO-based sorbents fabrication technique is promising for industrial application.

Cyclotron Production of 99Mo Radionuclide by Bombarding Zirconium Targets with Alpha Particle Beams

A possibility of manufacturing 99Mo via a nuclear reaction with 96Zr (α, n) in the R-7 cyclotron of the Tomsk polytechnic university is investigated. The beam energy of α-particles is 27 MeV for the beam current values 13, 15 and 22 μA. The targets are manufactured from natural zirconium shaped as disks measuring 30 mm in diameter and 1.5 mm in thickness. As a result of the experiments the designed yield of 99Mo is found to be on the order of (1.62 ± 0.15) (MBq/(μA·h) for 96Zr targets with 100% enrichment, which closely agrees with the yields reported by other authors. It is shown that a sufficient amount of 99Mo can be output for technetium-99m to be manufactured at a regional level.

Green synthesis of Cu/zirconium silicate nanocomposite by using Rubia tinctorum leaf extract and its application in the preparation of N‐benzyl‐N‐arylcyanamides

A simple and convenient protocol was established for the synthesis of the N‐benzyl‐N‐arylcyanamides through N‐benzylation of a wide variety of arylcyanamides using copper nanoparticles immobilized on natural zirconium silicate as a novel and green heterogeneous catalyst. In this study, we showed a novel, cost efficient, convenient and simple method for green synthesis of Cu/zirconium silicate nanocomposite by using Rubia tinctorum leaf extract as capping and reducing agent. The structure of the novel catalyst was successfully characterized using a number of micro/spectroscopic techniques such as XRD, FESEM, BET, EDS, TEM, FT‐IR and elemental mapping. TEM micrographs of obtaining biocatalyst revealed mostly spherical particles with an average diameter of about 15–25 nm on the surface of natural support. The prepared catalyst was used in the N‐benzylation of a variety of arylcyanamides with benzyl bromide and showed high activity and stability for the efficient synthesis of N‐benzylarylcyanamides in good yields. Remarkably, the catalyst can be easily recovered from the reaction medium and reused up to five runs without losing its catalytic activity.

Production cross sections of Mo, Nb and Zr radioisotopes from α-induced reaction on natZr

Cross sections of α-induced reactions on natural zirconium were measured up to 50 MeV using the stacked-foil technique, activation method and high resolution γ-ray spectrometry. The production cross sections of 93m,99Mo, 90g,92m,95g,95m,96Nb and 88,89g,95Zr were determined and compared with other experimental data measured earlier and result of theoretical calculations. The integral thick target yield of 99Mo was deduced from the measured cross section data.

Measurement of production cross sections in proton induced reactions on natural zirconium

The production cross sections of 90g,92m,95gNb, 86,88,89g,95Zr, 86g,87m,87g,88Y, 85gSr, and 83Rb in a proton induced nuclear reaction of natural zirconium were measured within the proton energy range of 35.7–66.6 MeV at the Korea Multi-purpose Accelerator Complex (KOMAC), Gyeongju, Korea. The excitation functions of radionuclides produced from the natZr(p,x) reactions were determined through a stacked-foil activation method and an off-line γ-ray spectroscopy. A high purity germanium (HPGe) detector was used to measure the induced activities of the radionuclides. The incident beam energy in each foil was calculated from the SRIM code. The proton flux was determined by using the natCu(p,x)62Zn monitor reaction. The measured data were compared with the experimental data in the literature and the data from the TENDL-2017 library based on the TALYS code. The present results are in general agreement with the literature data and in some cases with the calculated data from the TENDL-2017 library. However, in some of the cases, the calculated data from the TENDL-2017 library overestimate or underestimate the experimental data.

The physical and mechanical properties and local deformation micromechanisms in materials with different dependence of hardness on the depth of print

The size hardness effects are studied via the micro- and nanoindentation methods over the wide range of the depth of print h (from dozens of nanometers to several dozen micrometers) for several classes of materials, such as ionic and covalent single crystals (sapphire, silicon, lithium fluoride); metals (single-crystal Al, polycrystalline Cu, Ni, and Nb); ceramics (high-strength nanostructured TZP-ceramic based on the natural zirconium dioxide–baddeleyite mineral); amorphous materials (fused quartz); and polymers (polycarbonate and polytetrafluoroethylene). As is shown, some of them possess severe size hardness effects, whereas the others reveal the weak ones or even a lack of these effects. The thermoactivation analysis is implemented, as well, and the activating and energy characteristics of local deformation processes induced by an indenter are compared with the dominant plasticity micromechanisms of the studied materials at different stages of the print formation and with the size peculiarities. The materials with low hardness coefficients and meeting the requirements of ISО 14577 and GOST R 8.748-2011 standards in the nanohardness measurements are highlighted, as well. In the established load ranges, these materials are the promising candidates for their use as reference samples, which are designed to ensure the uniformity of the hardness measurements at the nano- and microscales, as well as for calibrating and testing the nanoindentometers.

New limit for the half-life of double beta decay of 94Zr to the first excited state of 94Mo

Neutrinoless Double Beta Decay is a phenomenon of fundamental interest in particle physics. The decay rates of double beta decay transitions to the excited states can provide input for Nuclear Transition Matrix Element calculations for the relevant two neutrino double beta decay process. It can be useful as supplementary information for the calculation of Nuclear Transition Matrix Element for the neutrinoless double beta decay process. In the present work, double beta decay of $^{94}$Zr to the $2^{+}_{1}$ excited state of $^{94}$Mo at 871.1 keV is studied using a low background $\sim$ 230 cm$^3$ HPGe detector. No evidence of this decay was found with a 232 g.y exposure of natural Zirconium. The lower half-life limit obtained for the double beta decay of $\rm^{94}Zr$ to the $2^{+}_{1}$ excited state of $\rm^{94}Mo$ is $T_{1/2} (0\nu + 2\nu)> 3.4 \times 10^{19}$ y at 90% C.L., an improvement by a factor of $\sim$ 4 over the existing experimental limit at 90\% C.L. The sensitivity is estimated to be $T_{1/2} (0\nu + 2\nu) > 2.0\times10^{19}$ y at 90% C.L. using the Feldman-Cousins method.

Isotopically modified molybdenum for safe nuclear power

The possibility of applying isotopically modified molybdenum like the structural material of fuel elements for light-water and fast reactors with dispersed fuel containing granules of the metal U–Mo-alloy in Mo matrix, has been discussed. It has been shown that with isotope-modified molybdenum with the neutron capture cross-section close to natural zirconium, the improved safety of nuclear reactors, i.e., both thermal and fast-neutron reactors, due to the improvement of heat-transfer emission in fuel elements has been achieved. Assessments demonstrated that molybdenum with economic practical cost may be obtained on the existing cascades of gas centrifuges developed for the separation of nonuranium isotopes.

Cross Sections for the \(^{nat}\)Zr\((p,xn)^{89,90}\)Nb Reactions Induced by 27.7 MeV Protons

The cross-sections for the formation of \(^{89}\)Nb and \(^{90}\)Nb radionuclides in proton induced nuclear reactions on zirconium were measured by using the well known activation method. The natural zirconium (\(^{nat}\)Zr) target and copper (\(^{nat}\)Cu) monitor foils were irradiated by 27.7 MeV proton beam at the MC50 Cyclotron of the Korea Institute of Radiological and Medical Science (KIRAMS), Korea. The induced gamma activities of the reaction products were measured by a coaxial high purity germanium (HPGe) detector coupled to a PC-based multichannel analyzer. The obtained cross sections for each nuclide are compared with those existing in literature and with the theoretical cross sections calculated by the TALYS - 1.4 code.

Excitation functions of natZr + p nuclear processes up to 70 MeV: New measurements and compilation

Excitation functions for the formation of various radionuclides of Nb, Zr, Y and Sr in proton-induced reactions on natural zirconium were measured up to 66MeV using the stacked-foil technique. New data are presented for 89m,89gNb, 90(m+g)Nb, 91mNb, 92mNb, 95m,95gNb, 96Nb, 86Zr, 87(m+g)Zr, 88Zr, 89(0.94m+g)Zr, 95Zr, 85m,85gY, 86m,86(0.99m+g)Y, 87m,87(0.984m+g)Y, 88Y, 90mY, 91mY and 85(0.87m+g)Sr. The experimental results are compared with the available literature data as well as the evaluated theoretical predictions by means of the TALYS code, up to 70MeV, as compiled in the TENDL-2013 library. For a number of short-lived radionuclides, i.e., 85mY, 85gY, 86mY, 90mY, 91mY and 87(m+g)Zr, the present experimental cross sections are likely the first to be reported for their formation in natZr+p.

Experimental cross section evaluation for innovative 99Mo production via the (α,n) reaction on 96Zr target

The high-specific activity 99Mo accelerator-based production, via the (α,n) reaction on 96Zr-enriched target, has been investigated in the present work. The excitation function measurement has been performed in the energy range 8–34 MeV at the ARRONAX facility, using the well-known stacked foils technique on natural zirconium as target. A general good agreement in the cross section trend has been observed, once compared to former measurements. A different (i.e. higher) peak value and a shift of about 2 MeV towards larger energies have however been found. Assuming a fully enriched 96Zr target irradiated by an α-beam at suitable energy (E = 25 MeV), the 99Mo production yield has thus been estimated. At last the alternative production routes, based on the 96Zr(α,n)99Mo and 100Mo(p,x)99Mo/99mTc reactions, are compared.

Сорбционно-фотометрическое и тест-определение общего содержания железа в природных водах с использованием сорбентов на основе оксида циркония, модифицированного полигексаметиленгуанидином, феррозином и ференом С

Сорбционно-фотометрическое и тест-определение общего содержания железа в природных водах с использованием сорбентов на основе оксида циркония, модифицированного полигексаметиленгуанидином, феррозином и ференом С

A new adsorbent for boron removal from aqueous solutions

A new adsorbent based on natural clinoptilolite and amorphous zirconium dioxide (ZrO2) was prepared for the uptake of boron from fresh water. The sorption behaviour of this adsorbent for boron was investigated using a batch system and found to obey Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. The ZrO2 loading level, pH, temperature, contact time, initial boron concentration and adsorbent dose, on the removal of boron were studied. It was found that the removal of boron increased while the adsorbent dose increased and the temperature decreased at an optimum pH (pH=8) and a contact time of 30 min. At optimum conditions, the maximum boron percentage removal was 75%. According to the D–R model, the maximum capacity was estimated to be>3 mg B/g of the adsorbent. The adsorption energy value (calculated as 9.13 kJ/mol) indicated that the adsorption of boron on clinoptilolite modified with ZrO2 was physical in nature. The parameters of the adsorption models and the pH investigations pointed to the possibility of a chemisorption process. The thermodynamic parameters (standard entropy Δ S°, enthalpy Δ H°, and free energy Δ G° changes) of boron adsorption were also calculated. The negative value of Δ S° indicated a decreased randomness at the solid–solution interface during the boron adsorption. Negative values of Δ H° showed the exothermic nature of the process. The negative values of Δ G° implied that the adsorption of boron on clinoptilolite modified with amorphous ZrO2 at 25°C was spontaneous. It was considered that boron dissolved in water had been adsorbed both physically and chemically on clinoptilolite modified with 30% ZrO2.

90Nb – a potential PET nuclide: production and labeling of monoclonal antibodies

Abstract Fast progressing immuno-PET gives reasons to develop new potential medium-long and long-lived radioisotopes. One of the promising candidates is 90Nb. It has a half-life of 14.6 h, which allows visualizing and quantifying processes with medium and slow kinetics, such as tumor accumulation of antibodies and antibodies fragments or polymers and other nanoparticles. 90Nb exhibits a high positron branching of 53% and an optimal energy of β + emission of E mean=0.35 MeV only. Consequently, efficient radionuclide production routes and NbV labeling techniques are required. 90Nb was produced by the 90Zr(p,n) 90Nb nuclear reaction on natural zirconium targets. No-carrier-added (n.c.a.) 90Nb was separated from the zirconium target via a multi-step separation procedure including extraction steps and ion-exchange chromatography. Protein labeling was exemplified using the bifunctional chelator desferrioxamine attached to the monoclonal antibody rituximab. Desferrioxamine was coupled to rituximab via two different routes, by the use of N-succinyl-desferrioxamine (N-suc-Df) and by means of the bifunctional derivative p-isothiocyanatobenzyl-desferrioxamine B (Df-Bz-NCS), respectively. Following antibody modification, labeling with 90Nb was performed in HEPES buffer at pH 7 at room temperature. In vitro stability of the radiolabeled conjugates was tested in saline buffer at room temperature and in fetal calf serum (FCS) at 37 ºC. The selected production route led to a high yield of 145 ± 10 MBq/μA h of 90Nb with high radioisotopic purity of >97%. This yield may allow for large scale production of about 10 GBq 90Nb. The separation procedure resulted in 76–81% yield. The Zr/90Nb decontamination factor reaches 107. Subsequent radiolabeling of the two different conjugates with 90Nb gave high yields; after one hour incubation at room temperature, more than 90% of 90Nb-Df-mAb was formed in both cases. At room temperature in aqueous solution, both 90Nb-Df-mAb constructs were more than 99% stable over a period of 18 d. The developed production and separation strategy provided 90Nb with purity appropriate for radiolabeling applications. Labeling and stability studies proved the applicability of 90Nb as a potential positron emitter for immuno-PET.