Zirconium Isotopes Research Articles

Study of the Nuclear Structure Properties in Strontium (90,92,94Sr) Isotopes Using Nuclear Shell-model Calculations

In the current research, various nuclear properties energy spectrum, reduced electromagnetic transition probabilities, nuclear moments, and the distributions of both the nuclear charge and mass density as a function of radial distance from the nucleus center (r) were computed for90,92,94Sr isotopes' using the NuShellX@MSU code. The Skyrme (SLy4) potential was utilized to compute the zirconium isotopes' wave functions with mass numbers 90, 92, and 94. By employing the Gloeckner interaction and bare G-matrix, the computed results showed good agreement with the available experimental information on the aforementioned nuclear features of all the above isotopes. Additionally, the spins and parities of energy levels were confirmed and determined in accordance with certain empirical values. Furthermore an acceptable agreement for transition strengthsB(E2;2_1^+→0_1^+ ) for 90,92,94Sr , and the dipole magnetic moment of the ground state in the90Sr isotope, was observed with the available experimental values. In these calculations, new values were predicted for the above nuclear properties, which had not been previously determined experimentally. KEYWORDS: energy spectra; gloeckner interaction; model space; nuShellX code; skyrme potential; transition strengths

Zirconium isotope tracing of the magmatic-hydrothermal transition

Zirconium (Zr) isotope has significant potential for tracing magmatic processes, particularly late-stage fractionation involving fluids. However, the fractionation of Zr isotopes between magma and fluid is still unclear. In-situ Zr isotope analyses of zircons from three granite-pegmatite suites in the Tibetan plateau show a wide range of δ94/90Zr values (IPGP-Zr) between −0.23 ‰ and +1.38 ‰, with the highest values in hydrothermally altered zircons from pegmatites. A coupled dissolution-reprecipitation process of zircons in a zircon-undersaturated melts is the most plausible mechanism to explain the strong enrichment of heavy Zr isotopes in hydrothermally altered zircons. During the formation of granitic pegmatite, exsolution of F-Na-Si-bearing fluids can enhance zircon solubility and will significantly remove Zr from the melt. Faster diffusion of 90Zr into the fluid channel will result in preferential accumulation of light Zr isotopes in the fluid, and drive the residual melt towards heavier Zr isotopes under disequilibrium conditions. Later, the reprecipitated zircons will inherit the heavy Zr isotope composition of the melt. Rayleigh fractionation models suggest fluid-melt fractionation factors for Zr isotope of about 0.99911–0.99930. This shows the major controls of fluid on Zr isotope fractionation during crystal-magma-fluid differentiation. Thus Zr isotope can be a powerful tracer of the magmatic-hydrothermal transition.

89Zr production with electron accelerators by irradiating molybdenum

89Zr is a promising radionuclide for high-resolution PET imaging with radiolabelled monoclonal antibodies. In the present study, the possibility of 89Zr production from molybdenum targets was investigated using electron accelerators. The 89Zr activity yields were determined experimentally for bremsstrahlung with endpoint energies of 20 and 55 MeV. The amount of radioactive impurities and stable zirconium isotopes associated with the 89Zr produced was estimated using experimental results and the TALYS 1.96 code. The conditions for achieving a minimum level of zirconium by-product isotopes to meet the expected clinical requirements are discussed in the article. The reaction 92Mo (γ, p2n)89Nb→89Zr was found to be the most promising for photonuclear production. It can provide the highest purity of zirconium radionuclide and the lowest amount of zirconium stable isotopes. A major advantage of the proposed method will be the ability to use natural molybdenum targets.

Intertwined quantum phase transitions in the zirconium and niobium isotopes

Nuclei in the A ≈ 100 region exhibit intricate shape-evolution and configuration crossing signatures. Exploring both even–even and their adjacent odd-mass nuclei gives further insight on the emergence of deformation and shape-phase transitions. We employ the algebraic frameworks of the interacting boson model with configuration mixing and the new interacting boson-fermion model with configuration mixing in order to investigate the even–even zirconium with neutron number 52–70 (40Zr) and odd-mass niobium (41Nb) isotopes with 52–62. We compare between the evolution in energy levels, configuration and symmetry content of the wave functions, two neutron separation energies and E2 transition rates, alongside comparison with the experimental data. The comparisons between the two chains of isotopes denote the occurrence of two types of QPTs, a crossing of normal and intruder configurations (named Type II QPT), and a shape-evolution of the intruder configuration (named Type I QPT). The latter QPT begins from spherical shape to axially deformed rotor in the Zr isotopes and from weak to strong coupling scenario in the Nb isotopes. This occurrence, named intertwined quantum phase transitions (IQPTs), in the even–even Zr chain is thus demonstrated to persists when coupling a proton to the boson core for the odd-mass Nb chain, even as deformation increases.

Zircon Zr[sbnd]Hf isotope disequilibrium during crustal anatexis: A record from the Mesozoic migmatite in the eastern Gangdese arc, South Tibet

Stable zirconium (Zr) isotopes have become the focus of attention as potential tracers of magma crystallization and differentiation processes. However, the effects of partial melting, especially disequilibrium melting, on Zr isotope fractionation remain unclear. Here we report in-situ zircon UPb ages, major and trace elements, and ZrHf isotope data for the migmatites in the eastern Gangdese arc, South Tibet. The leucosomes from the metatexite and diatexite migmatites are generally concordant with the foliation of the paleosome and display diffuse and gradational contacts with the melanosomes, indicating that they are in-source leucosomes. Zircon in the paleosome, the protolith of the migmatites, have UPb age of 361 ± 2 Ma and low 176Hf/177Hf ratios of 0.282399–0.282482. They exhibit intragrain variation in δ94/90Zr values, increasing from the core (−0.10 ‰ to +0.36 ‰) to the rim (+0.14 ‰ to +0.55 ‰) domains. The negative correlation between δ94/90Zr values and Zr/Hf ratios suggests preferential incorporation of light Zr isotopes during the crystallization of the zircon in the protolith. Most zircon in the leucosomes from the metatexite and diatexite migmatites exhibit distinct overgrowth rims around the inherited cores. The inherited cores have consistent UPb ages (ca. 360 Ma), trace elements, and Hf isotopic compositions (0.282362–0.282449) with zircon in the paleosome, indicating in situ partial melting. The inherited cores display δ94/90Zr values ranging from −0.12 ‰ to +0.31 ‰, consistent with the zircon core domains in the paleosome. The overgrowth rims have UPb ages of ca. 102 Ma and display higher 176Hf/177Hf ratios (0.282592–0.282900) and δ94/90Zr values (+0.01 ‰ to +0.63 ‰) than their inherited cores. The elevated 176Hf/177Hf for the overgrowth rims resulted from the retention of unradiogenic 177Hf in the residue due to limited zircon dissolution and more release of radiogenic 176Hf to the melts because of the garnet breakdown, indicating disequilibrium melting. The elevation of δ94/90Zr for the overgrowth rims relative to the inherited cores was not caused by the disequilibrium melting of other Zr-bearing minerals but was mainly controlled by the Zr isotopic composition and dissolution degree of the zircon in the protolith. The preferential melting of isotopically heavy zircon rims would elevate the δ94/90Zr values in the melts relative to their zircon-bearing protoliths. Crustal anatexis may be another important mechanism contributing to the Zr isotope fractionation during crustal differentiation.

Probing isoscalar giant monopole resonance in axially and triaxially deformed zirconium isotopes

Probing isoscalar giant monopole resonance in axially and triaxially deformed zirconium isotopes

Ниобий в проблеме обеспечения долговременной радиационной безопасности

The article provides a general overview discussing niobium and partially zirconium isotopes and their behavior in experimental and natural environments. In terms of weight, zirconium and niobium isotopes account for a quite tangible fraction of radioactive waste streams generated by nuclear industry. As it comes to natural environments, the behavior of substances containing these isotopes has been poorly studied even over the initial period of their one-time intake. Moreover, their chronic long-term intake over hundreds and thousands of years hasn’t been basically studied at all, which raises certain difficulties when demonstrating the long-term safety of radioactive waste disposal. This overview also evaluates the experimental studies focused on niobium behavior in natural environments, as well as some individual hypotheses about its potential behavior. The paper evidences that new experimental studies should be launched to support the forecasts regarding niobium isotope impacts on various types of biota, including human.

High-precision zirconium isotope analysis of Pacific seawater reveals large mass-dependent fractionations in the ocean

Zirconium (Zr) stable isotopes recently emerged as potential tracers of magmatic processes and, as a result, their behavior in high-temperature environments have been the focus of extensive characterization. In contrast, few studies have focused on Zr behavior and isotopic fractionation in low temperature or aqueous environments. Here, we describe a new analytical routine for highly precise and accurate analysis of Zr isotopes of water samples, using a combination of double-spike and iron co-precipitation methods. To assess the impact of potential systematic biases a series of experiments were conducted on natural and synthetic water samples. Our results show that the spike-to-sample ratio, matrix composition, and high field-strength element (HFSE) concentration have negligible effects on measured seawater Zr isotopic compositions, and that the Fe co-precipitation method used yields accurate and precise Zr isotope data. We thus apply this method to natural seawater samples collected from a water column profile in the Pacific Ocean off the coast of California, with depths ranging from 5 to 711 m. We find that the natural seawater samples are highly fractionated relative to solid-Earth values and display marked variability in δ94/90Zr as a function of depth, ranging from ∼ +0.650 ‰ near the surface, to + 1.530 ‰ near the profile bottom, with an analytical uncertainty of ± ∼0.045 ‰ (2 SE, external reproducibility). The δ94/90Zr value of seawater is much higher than that of Earth’s mantle and continental crust, which has a δ94/90Zr value near zero, indicating the presence of processes in the hydrosphere capable of inducing large mass-dependent fractionation. Furthermore, the seawater δ94/90Zr value exhibits systematic variations with respect to water depth and salinity, suggesting that Zr isotopic compositions may be sensitive to seawater chemical properties and source highlighting its potential utility as a tracer of biogeochemical processes within the ocean.

Zirconium and neodymium isotopes record intensive felsic volcanism in South China region during the Permian-Triassic boundary crisis

The Permian-Triassic mass extinction (PTME), the largest biocrisis in Earth's history, is regarded as having been triggered by volcanism, although the source and nature of this volcanic activity in the South China region remains in debate. In this regard, determining the geochemical composition of the volcanic and terrestrial source fluxes to marine depositional systems is crucial for differentiating material derived from the Siberian Traps Large Igneous Province versus regional volcanic arcs. Here, we report zirconium (Zr) isotopic compositions (δ94/90Zr) of Permian-Triassic boundary strata from a deep carbonate-ramp setting at Xiakou, South China, providing new insights regarding the provenance of volcanic ash layers and their host silicic mudstones. The δ94/90Zr composition of magmatically sourced materials is generally controlled by degree of melt crystallization and has the potential to discriminate between primitive and evolved igneous sources. At Xiakou, the pre-PTME Lower Unit contains volcanic ash layers with δ94/90Zr (+0.05 ± 0.03‰, 2SD) similar to that of upper continental crustal (UCC), recording dominantly detrital zircon sources. About 10 kyr before the mass extinction, a single ash layer (Bed 249) records a transient excursion to mantle-like values (∼0‰), followed by a protracted shift across the Permian-Triassic boundary (PTB) toward signatures characteristic of more evolved felsic sources (+0.19 ± 0.12‰) accompanied by a positive shift in Nd isotopes (εNd(t)). The high δ94/90Zr of volcanic ash layers from the Middle Unit (corresponding approximately to the interval between the PTME and PTB) indicates dominance of regional felsic volcanic sources. In this interval, volcanic ash δ94/90Zr values at Xiakou are distinctly higher than those at Meishan, suggesting that primary volcanic signatures are better preserved in deep-water facies (Xiakou) than in shallow-water facies (Meishan). In the Middle (excluding the Bed 249) and Upper (post-PTME) units, positive covariation of δ94/90Zr with Al2O3/TiO2, Zr/TiO2 and Zr/Sc ratios was the product of mixing of detrital and volcanic materials, with the latter having a dominantly felsic source. This study provides new insight into the sources of zircons in PTB sections of South China, and it demonstrates the general utility of sedimentary Zr isotopic compositions in determining magmatic provenance.

Characterisation of Three Sri Lankan Zircon Megacrysts as Potential Reference Materials for Microbeam U‐Pb Geochronology and Hf‐O‐Zr Isotope Measurements

In situ U‐Pb geochronology and hafnium, oxygen and zirconium isotope measurements in zircons using laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) and ion microprobe techniques can provide essential isotopic data to constrain geological evolutionary histories. Developing reliable zircon reference materials is the cornerstone for in situ zircon chronology and isotopic studies. In this study, the homogeneity of U‐Pb ages and Hf‐O‐Zr isotope ratios in three Sri Lankan zircon megacrysts (SLZA, SLZB and SLZC) were investigated using multiple analytical methods. The obtained U, Th, Pb and Hf mass fractions of the SLZA zircon were 839 ± 56 μg g‐1 (1s), 151 ± 15 μg g‐1 (1s), 198 ± 28 μg g‐1 (1s) and 8635 ± 286 μg g‐1 (1s), respectively. The mass fractions of U, Th, Pb and Hf in the SLZB zircon were 1106 ± 106 μg g‐1 (1s), 331 ± 61 μg g‐1 (1s), 376 ± 57 μg g‐1 (1s) and 9673 ± 976 μg g‐1 (1s), respectively. The U, Th, Pb and Hf mass fractions determined in the SLZC zircon were 551 ± 35 μg g‐1 (1s), 111 ± 8 μg g‐1 (1s), 129 ± 18 μg g‐1 (1s) and 7881 ± 393 μg g‐1 (1s), respectively. The chemical abrasion isotope dilution thermal ionisation mass‐spectrometry (CA‐ID‐TIMS) method yielded a Th‐corrected weighted mean 206Pb/238U age of 556.94 ± 1.29 Ma (95% conf., n = 5) for the SLZA zircon, 552.90 ± 1.29 Ma (95% conf., n = 7) for the SLZB zircon and 560.83 ± 1.29 Ma (95% conf., n = 7) for the SLZC zircon. The obtained Hf isotopic compositions of the SLZA, SLZB and SLZC zircons determined with the solution MC‐ICP‐MS method were 0.281651 ± 0.000014 (2s, n = 10), 0.281704 ± 0.000008 (2s, n = 10) and 0.281676 ± 0.000006 (2s, n = 10), respectively. The obtained O isotopes of the SLZA and SLZB zircons measured with the laser fluorination method were 12.14 ± 0.56‰ (2s, n = 4) and 11.91 ± 0.30‰ (2s, n = 4), respectively. The Zr isotopes of the SLZA, SLZB and SLZC zircons determined with double spike TIMS analysis yielded mean δ94/90ZrSRM3169 values of ‐0.03 ± 0.06‰ (2s, n = 10), ‐0.03 ± 0.04‰ (2s, n = 10) and 0.00 ± 0.07‰ (2s, n = 8), respectively. The SLZA zircon can be used as a primary reference or quality control material for microbeam U‐Pb, Hf and Zr isotope measurements because of its slight heterogeneity. The U‐Pb, Hf and Zr isotopic compositions of the SLZB and SLZC megacrysts were homogeneous. The O isotopic compositions in the SLZA and SLZB zircon were slightly dispersed, indicating that these two megacrysts can only serve as secondary reference materials for microbeam O isotope measurements.

Two-particle transfer processes as a signature of shape phase transition in Zirconium isotopes

We explore two-particle transfer reactions as a crucial probe of the occurrence of shape coexistence in shape phase transitions. The (t,p) reactions to the ground state and to excited 0+ states are calculated for the isotope chain of even-even Zirconium isotopes starting from stable nuclei up to beyond current experimental limits. Two-particle spectroscopic factors derived from Monte Carlo Shell Model calculations are used, together with the sequential description of the two-particle transfer reaction mechanism. The calculation shows a clear signature for a shape phase transition between 98Zr and 100Zr, which displays coexistence of a deformed ground state with an excited spherical 0+ state. Furthermore, we show that there is a qualitative difference with respect to the case of a normal shape phase transition that can be discriminated with two-neutron transfer reactions.

Ban‐1 Zircon: A New Natural Zircon Reference Material for LA‐MC‐ICP‐MS Zr and Hf Isotopic Determinations

New zircon reference materials for in situ zircon radiogenic Hf isotope and stable Zr isotopic determinations made by laser ablation multi‐collector inductively coupled plasma‐mass spectrometry (LA‐MC‐ICP‐MS) are required due to high data productivity and consequently high reference material consumption rate. This study examines a new natural zircon for Zr isotope ratios by double spike thermal ionisation mass spectrometry (TIMS), and for Hf isotopes by bulk solution nebuliser (SN)‐MC‐ICP‐MS with both Zr and Hf determined by LA‐MC‐ICP‐MS. A total of five zirconium isotope measurements from drilled zircons, determined by TIMS, yield a mean δ94/90ZrIPGP‐Zr value of ‐0.09 ± 0.06‰ (2s). Five and eight hafnium isotope measurements for powders from the drilled zircons and Ban‐1‐4 by SN‐MC‐ICP‐MS, yield mean 176Hf/177Hf ratios of 0.282985 ± 0.000011 (2s) and 0.282982 ± 0.000007 (2s), respectively. The mean δ94/90ZrIPGP‐Zr value and 176Hf/177Hf ratio determined by LA‐MC‐ICP‐MS analyses are ‐0.06 ± 0.09‰ (2s, n = 504) and 0.282985 ± 0.000035 (2s, n = 327), respectively. The isotopic homogeneities suggest that the Ban‐1 zircon is a suitable reference material for microbeam Zr and Hf isotopic measurements.

Zirconium isotopic composition of zircon reference materials by laser ablation multi-collector inductively coupled plasma mass spectrometry

Zirconium isotopes have been suggested as a new geochemical fingerprint for tracing magmatic evolution and continental crust differentiation. In this study, we optimized the Zr isotope measurement by laser-ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) and reported stable Zr isotope compositions for different zircon reference materials (ZRMs). The RESOLution laser, coupled with MC-ICP-MS, yielded better results than the New Wave laser when comparing crater shape and depth indices, signal intensity, and isotopic ratio variations. The best working conditions for Zr isotope measurements were found to be with a laser spot size of 23 μm, a repetition rate of 2 Hz, and energy density of 3 J cm−2 which resulted in a crater depth of ∼8 μm. The 90Zr intensities increased by a factor of 3.2, and the raw 94Zr/90Zr ratio remained constant within a broader range of sample gas flow rate with the addition of 8 mL min−1 N2 compared to the normal mode. Negligible interferences were identified from the gas blank and also from the different integrated cycles between the bracketing standard and samples. Using the above-mentioned parameters, we obtained a long-term δ94/90ZrGJ-1 stability of 0.08‰, comparable with femtosecond laser-ablation (fsLA)-MC-ICP-MS methods. ZRMs (e.g., 91,500, Plešovice, Penglai, SA01, Tanz, and Ban-1) yielded homogeneous Zr isotope compositions, consistent with double spiked solution methods within error. Furthermore, zircon megacrysts of LKZ-1 and Cam-1, synthetical MUN-zircon with high Yb content, and MTUR1 zircon standard from carbonatite also had homogeneous Zr isotope compositions that indicate they could be used as tuning and monitoring standards. On the contrary, GHR1, Temora-2, Qinghu, and Jilin zircons were not ideal ZRMs for Zr isotope measurement. Zr isotope variations among homogeneous ZRMs (except Plešovice) further prove that Zr isotopes are a potentially powerful geochemical tracer.

Magmatic crystallization drives zircon Zr isotopic variations in a large granite batholith

Stable zirconium (Zr) isotope of magmatic zircons is a promising new tracer to understand magma differentiation in the continental crust. However, magmatic processes controlling zircon Zr isotopic variations remain poorly constrained. Here we present high-spatial-resolution in-situ methods on magmatic zircons for U-Pb age, trace elements, Hf isotopes, and stable Zr isotopes (δ94/90Zr relative to IPGP-Zr) as well as bulk rock δ94/90Zr for a large granite batholith (SiO2 = ∼73 wt%) in the Jiaodong Peninsula, eastern North China Craton. Magmatic zircons are classified into high-luminance Type-I and low-luminance Type-II zircons in the cathodoluminescence images. Both types show indistinguishable U-Pb ages and initial Hf isotopic compositions, indicating their same magma source. Yet, they differ in chemical compositions and δ94/90Zr values. Type-I zircons display lower δ94/90Zr values (−0.35‰ to 0.15‰) than Type-II zircons (0.16–0.54‰). The δ94/90Zr values overall increase with decreasing Zr/Hf, Th/U ratios, Ti-in-zircon temperature, and increasing U abundances in zircons, implying that zircon δ94/90Zr values becomes heavier with the enhanced magma differentiation. Such concomitant correlations resulted from closed-system magma crystallization without noticeable segregation of feldspar and zircon, as revealed by high Sr and Ba content, limited Eu anomalies, and mantle-like δ94/90Zr in the bulk rocks (−0.01 ± 0.07‰ and 0.02 ± 0.04‰). Thus, Type-I zircons incorporating light Zr isotopes crystallized at an early stage of magma solidification, while Type-II zircons grew from more evolved residual melts with elevated δ94/90Zr values. Zoned zircon grains with Type-I cores and Type-II rims record the prolonged crystallization history covering both stages with contrasting melt compositions; whereas oscillation zircon grains of Type-I or Type-II, crystallizing at the stable melt composition, display the restricted intragrain variations of δ94/90Zr, Zr/Hf, and Th/U ratios. These results demonstrate that closed-system magmatic crystallization plays a critical role in zircon Zr isotopic variations. We further propose that the variability of δ94/90Zr values and multiple types of Zr isotopic profiles in zircons are predominantly driven by the compositional effect of adjacent melts from which zircons crystallize. The composition-related δ94/90Zr variations provide a fundamental framework for understanding Zr isotopic evolution in the silicic igneous system and can be used for exploring open-system magmatic processes in the mushy pluton bodies, which are important for continental crust evolution.

The rises and falls of zirconium isotopes during zircon crystallisation

The rises and falls of zirconium isotopes during zircon crystallisation

Deformation parameters and nuclear radius of Zirconium (Zr) isotopes using the Deformed Shell Model

In this search we studied the most important deformation parameters (beta 2, and sigma), root mean square of nuclear radius and major and minor of ellipsoid axises (a,b) in addition to the different -even Zirconium (Zr) isotopes (Z=40) for atomic number (A=80 → 104), using deformed shell model equations as a simple new program in Matrix Laboratory system.

Zirconium isotopes track volcanic inputs during the Permian-Triassic transition in South China

The Permian-Triassic mass extinction (PTME), the most severe biocrisis of the Phanerozoic, has been widely attributed to intense volcanism. Although the Siberian Traps Large Igneous Province is regarded as the main trigger of this bioevent, volcanic-arc activity around the margins of the Tethys Ocean may have played a significant role also. Here, we report results of a high-resolution study of zirconium (Zr) isotopes in bulk limestone and volcanic ash beds of the Permian-Triassic transition at Meishan, South China. Mass-dependent fractionation of Zr isotopes, which is controlled by magmatic crystallization, has the potential to differentiate between primitive and evolved igneous sources. The Zr isotopic composition (δ94/90Zr) of volcanic ash in Permian-Triassic transition beds at Meishan is more positive than mantle values, indicating that inputs were probably dominated by regional arc volcanism. The sedimentary beds having the heaviest Zr isotopes during the pre-PTME interval may also record inputs from a felsic volcanic source. A mixing model indicates that the observed negative shift of δ94/90Zr at the PTME horizon was likely due to detrital Zr inputs linked to intensified continental weathering. This study demonstrates that volcanism in South China during the Permian-Triassic transition was linked to regional arc magmatism.

Zr isotopes as a region of intertwined quantum phase transitions

The zirconium isotopes with $A=92--110$ have one of the most complicated evolution of structure in the nuclear chart. In order to understand the structural evolution of these isotopes, we carry a detailed calculation in a definite symmetry-based framework, the interacting boson model with configuration mixing (IBM-CM). We compare our calculation to a large range of experimental data, such as energy levels, two-neutron separation energies, $E2$ and $E0$ transition rates, isotope shifts, and magnetic moments. The structural evolution of the low lying spectra of these isotopes is explained using the notion of intertwined quantum phase transitions (IQPTs), for which a QPT involving a crossing of two configurations (Type II) is accompanied by a QPT involving a shape evolution of each configuration separately (Type I). In our study, we find the occurrence of Type I QPT within the intruder configuration, changing from weakly deformed to prolate deformed and finally to $\ensuremath{\gamma}$-unstable, associated with the U(5), SU(3) and SO(6) dynamical symmetry limits of the IBM, respectively. Alongside the Type I QPT, we also find the occurrence of Type II QPT between the normal and intruder configurations, where both Types I and II have a critical point near $A\ensuremath{\approx}100$. The good agreement of our calculation with the vast empirical data along the chain of isotopes demonstrates the relevance of IQPTs to the zirconium isotopes, and can serve as a case study to set path for new investigations of IQPTs in other nuclei and other physical systems.

Separation of zirconium and hafnium from early actinides and rare earth elements with eichrom’s pb resin in HCl

The separation of zirconium and hafnium isotopes from the early actinides and rare earth elements (REE) with Eichrom’s Pb resin has been studied. Batch studies were performed to characterize the behavior of actinium, thorium, zirconium, hafnium, lutetium, and yttrium on Pb resin from HCl solutions (0.001 M to 11 M). The early actinides and REE had no affinity for the resin at any concentration of HCl, but zirconium and hafnium showed a moderate uptake at high concentrations of HCl with a maximum extraction at 11 M HCl. Several column separations were tested, including with only tracer isotopes and with mass. Rapid, simple separations of zirconium from actinium, thorium, protactinium, and the REE with high yields and low elution volumes are presented with applications for tracer isotope production and fission product separations. The resin is less suitable for hafnium separations as hafnium tends to bleed off the resin even at high concentrations of HCl.

Constrained Optimization Criterion for Zirconium Isotope Separation by the Method of Laser-Assisted Retardation of Condensation

Constrained Optimization Criterion for Zirconium Isotope Separation by the Method of Laser-Assisted Retardation of Condensation