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Cadmium (Cd) isotopes have great potential for understanding Cd geochemical cycling in soil and aquatic systems. Iron (oxyhydr)oxides can sequester Cd via adsorption and isomorphous substitution, but how these interactions affect Cd isotope fractionation remains unknown. Here, we show that adsorption preferentially enriches lighter Cd isotopes on iron (oxyhydr)oxide surfaces through equilibrium fractionation, with a similar fractionation magnitude (Δ114/110Cdsolid-solution) for goethite (Goe) (−0.51 ± 0.04‰), hematite (Hem) (−0.54 ± 0.10‰), and ferrihydrite (Fh) (−0.55 ± 0.03‰). Neither the initial Cd2+ concentration or ionic strength nor the pH influence the fractionation magnitude. The enrichment of the light isotope is attributed to the adsorption of highly distorted [CdO6] on solids, as indicated by Cd K-edge extended X-ray absorption fine-structure analysis. In contrast, Cd incorporation into Goe by substitution for lattice Fe at a Cd/Fe molar ratio of 0.05 preferentially sequesters heavy Cd isotopes, with a Δ114/110Cdsolid-solution of 0.22 ± 0.01‰. The fractionation probably occurs during the transformation of Fh into Goe via dissolution and reprecipitation. These results improve the understanding of the Cd isotope fractionation behavior being affected by iron (oxyhydr)oxides in Earth’s critical zone and demonstrate that interactions with minerals can obscure anthropogenic and natural Cd isotope characteristics, which should be carefully considered when applying Cd isotopes as environmental tracers.

In this study, we develop a method for high precision Cd isotope analysis by double spike MC-ICP-MS. Two-step Cd purification using AG-MP-1M resin and TRU resin was used to separate Cd from samples with a recovery of more than 95% Cd and a blank less than 0.1 ng. A practical double spike design and optimization procedure is proposed and the effect of the double spike ratio in the double spike-sample mixture (p) on the measured δ114/110Cd is evaluated, which broadens the appropriate p range from 0.3–0.6 to 0.1–0.8. In addition, the observed shift/deviation of the measured δ114/110CdNIST 3108 value from zero-delta due to the change of experimental conditions is discussed on a theoretical basis and a correction approach is developed. Potential Mo and Zr based polyatomic ions have no significant effect on δ114/110Cd in typical geological samples, while isobaric ions such as Sn, Pd and In can seriously affect the accuracy of measurements even at low concentration. It is shown that the tolerances of isobaric interference can be improved to 0.1, 0.05 and 0.02 for Sn/Cd, Pd/Cd and In/Cd, respectively, after mass discrimination correction. The precision and accuracy of the proposed method were verified by analyzing mixtures of NIST 3108 and a secondary reference material BGEG-Cd of different composition. Long term monitoring of the measured NIST 3108 and BGEG-Cd showed repeatability for δ114/110Cd of 0.00 ± 0.04‰ and −1.00 ± 0.04‰ (2sd, n = 45), respectively. Finally, we measured Cd isotope compositions of several geological standard materials including soil sediments and manganese nodules, and the δ114/110Cd values of 0.01 ± 0.02‰ (GSD-5a), 0.04 ± 0.02‰ (GSD-7a), −0.06 ± 0.05‰ (GSD-10), −0.34 ± 0.06‰ (GSD-11), −0.10 ± 0.06‰ (GSD-12), 0.10 ± 0.04‰ (GSD-17), 0.05 ± 0.03‰ (GSD-21), and 0.10 ± 0.07‰ (GSD-23) were in good agreement with the reported values, and a δ114/110Cd value of −0.08 ± 0.04‰ (GSD-3a) was reported for the first time.

The drainage of rice soils increases Cd solubility and results in high Cd concentrations in rice grains. However, plant Cd uptake is limited by sorption to iron plaques, and Cd redistribution in the plant is regulated by the nodes. To better understand the interplay of Cd uptake and redistribution in rice under drained and flooded conditions, we determined stable Cd isotope ratios and the expression of genes coding transporters that can transport Cd into the plant cells in a pot experiment. In soil, both water management practices showed similar patterns of isotope variation: the soil solution was enriched in heavy isotopes, and the root Fe plaque was enriched in light isotopes. In rice, the leaves were heavier (Δ114/110Cdleaf-shoot = 0.17 to 0.96‰) and the nodes were moderately lighter (Δ114/110Cdnode-shoot = -0.26 to 0.00‰) relative to the shoots under flooded conditions, indicating preferential retention of light isotopes in nodes and export of heavy isotopes toward leaves. This is generally reversed under drained conditions (Δ114/110Cdleaf-shoot = -0.25 to -0.04‰, Δ114/110Cdnode-shoot = 0.10 to 0.19‰). The drained treatment resulted in significantly higher expression of OsHMA2 and OsLCT1 (phloem loading) but lower expression of OsHMA3 (vacuolar sequestration) in nodes and flag leaves relative to the flooded treatment. It appeared that OsHMA2 and OsLCT1 might preferentially transport isotopically heavier Cd, and the excess Cd was purposefully retranslocated via the phloem under drained conditions when the vacuoles could not retain more Cd. Cd in seeds was isotopically heavier than that in stems under both water management practices, indicating that heavy isotopes were preferentially transferred toward seeds via the phloem, leaving light isotopes retained in stems. These findings demonstrate that the Fe plaque preferentially adsorbs and occludes light Cd isotopes on the root surface, and distinct water management practices alter the gene expression of key transporters in the nodes, which corresponds to a change in isotope fractionation between shoots and nodes/leaves.

With new advancements in MC-ICP-MS technology, small Cd isotope fractionations in geological processes have attracted more interest in recent years. However, challenges remain in obtaining high-precision Cd isotope data for geological samples with low Cd concentrations and complex matrices. By an improved Cd purification and cleaning resin scheme for low-Cd samples using AGMP-1M resin with >90% Cd recovery, the ratios of trace elements Sn, Mo, Zr, etc. to Cd in the samples, which could potentially jeopardize the accuracy and precision of Cd isotope analysis under a high-sensitivity setup, were less than 0.001 after purification, and the total procedure blank is ≤0.1 ng. Hence, a sample containing 20–30 ng Cd can be employed for purification and subsequent isotope measurement. Cadmium isotope fractionation (expressed in δ114/110Cd relative to NIST 3108) during column separation and instrument mass bias was corrected for by a 111Cd–113Cd double spike. NIST 3108 was determined at a concentration of 5–25 ng mL−1 on a Neptune Plus (112Cd signal intensity: ∼640 V ppm−1) and 25–50 ng mL−1 on a Nu plasma III (112Cd signal intensity:∼280 V ppm−1) MC-ICP-MS equipped with an Aridus II/III desolvator for more than one year, with a total external analytical precision of 0.034‰ (2SD, n = 181). NIST SRM 2711a, NOD-P-1 and GSS-1 were measured at 5, 10, 20, 25 and 50 ng mL−1 levels to be 0.532 ± 0.038‰, 0.133 ± 0.038‰ and 0.098 ± 0.027‰, respectively, indicating that good accuracy and precision of Cd isotope analysis can be achieved with an injecting sample size as low as 5 ng Cd. Our method can be reliably applied to various geological reference materials (GRMs). The δ114/110Cd values of GRMs with relatively high and low Cd concentrations are consistent with previous studies: NOD-A-1 (0.124 ± 0.067‰), GSD-11 (−0.274 ± 0.037‰) and BCR-2 (−0.030 ± 0.063‰). SGR-1b (0.069 ± 0.049‰), GSH-1 (−0.337 ± 0.077‰) and others are reported for the first time in this paper. The δ114/110Cd in basalt and stream sediments is relatively homogeneous and overlaps with that of the bulk silicate earth (BSE). The δ114/110Cd in shale and soils varies greatly from −0.694 to 0.532‰. Human hair and other animal organs are enriched in light isotopes relative to BSE, whereas terrestrial plants are enriched in heavy isotopes.

Understanding oceanic cadmium (Cd) cycling is paramount due to its micronutrient‐like behavior in seawater, which has been inferred from its similarity to phosphate (PO4) cycling. Cadmium concentrations follow a nutrient‐like consumption‐regeneration cycle in the top of the water column and are mainly controlled by water mass mixing and circulation in the deep ocean. However, an additional scavenging mechanism through cadmium sulfide (CdS) precipitates, occurring within sinking biogenic particles in oxygen deficient zones (ODZ), has been proposed. In this study, we report Cd stable isotope and concentration data for seven vertical seawater profiles sampled during GEOTRACES cruise GA08 in the northern Cape and Angola Basins, which feature a significant ODZ along their eastern margins. Outside the ODZ, Cd cycling is similar to that previously reported for the South Atlantic. While water mass mixing largely controls deep ocean Cd isotope signatures, Cd isotope fractionation in surface waters can be modelled as an open system at steady‐state buffered by organic ligand complexation. In the ODZ, stronger Cd depletion relative to PO4 is associated with a shift in δ114Cd towards heavier values, which is indicative of CdS precipitation. Our interpretation is supported by experimental CdS precipitation data and a size‐resolved particle model involving bacterial sulfate reduction as a precursor of CdS. Our estimates of the CdS flux to the seafloor (107 to 109 mol yr‐1) indicate that CdS precipitation is a significant process of Cd removal and constitutes a non‐negligible Cd sink that needs to be better quantified by Cd isotope analyses of marine sediments.

Zinc (Zn) and cadmium (Cd) are two important biological-sensitive elements, and their isotopes are strongly fractionated during biological processes. To develop the potential application of Zn and Cd isotopes for tracing the contribution of bacteria to metal mineralization, in this study we investigate for the first time the ranges and causes of isotope fractionation of Zn and Cd in a large hydrothermal system with bacteria from the world-class Jinding Zn-Pb deposit, southwest China. Extremely negative δ34SCDT values of sulfides (−48.6‰ to +7.7‰) obtained in this study and literature reveal the dominant biogenic sulfur associated with bacterial sulfate reduction. Both Zn and Cd isotope ratios are highly variable and significantly lighter compared with most of Zn-Pb ore deposits worldwide. The extremely negative δ66ZnJMC 3-0749L (down to −0.69‰) exceeds the range of Rayleigh fractionation during inorganic precipitation of ZnS. Zinc isotope ratios display a well-defined positive correlation with Zn/Cd ratios and the samples with lightest δ66Zn have lowest Zn/Cd ratios. This reflects that sphalerites formed in the early stages of mineralization already have extremely light Zn isotopic compositions. There is a negative relationship between δ34SCDT and δ66Zn, indicating that lighter Zn isotope ratios are related to stronger bacterial sulfate reduction, which results in heavier sulfur isotope ratios. Since organic compounds (e.g., Zn-carboxylate) in fluids are strongly enriched in heavy isotopes relative to free Zn2+ and Zn-sulfide, sulfides formed in the bacteria-rich hydrothermal systems would acquire light δ66Zn. Therefore, the extremely negative δ34SCDT and δ66Zn ratios demonstrate for the first time that bacterial metabolisms not only induced sulfate reduction, but also were directly involved in the formation of metals (e.g., Zn) in a large hydrothermal system. A similar process may have also partly contributed to the substantial fractionation of cadmium isotopes in the hydrothermal system. Overall, our studies show that zinc and cadmium isotopes may act as an effective tool in deciphering the specific role of organisms in formation of sulfides in hydrothermal systems and other settings.

The neutron capture cross-sectional reactions for 106,108,110,111,112,113,114,116Cd isotopes have been calculated with different level density models which are constant temperature Fermi gas (CTFG) model, back-shifted Fermi gas model, generalized superfluid model and Hartree–Fock–Bogoliubov model by using TALYS 1.9 and EMPIRE 3.2 codes for incident neutron energies up to 250 keV. The obtained results have been analyzed with each level density model parameters existing in Reference Input Parameter Library (RIPL-3) and available experimental data. As an outcome, to obtain more precise and coherent calculations with the experimental values, level density model and its parameters have been determined. Also, hadronic interactions of low-energy neutrons have been investigated for a situation by using GEANT4. © 2019, Indian Association for the Cultivation of Science.

Cd isotopes (107Cd and 109Cd) are generated from the silver target body during the bombardment of [18O]water in the routine production of 2-[18F]fluoro-2-deoxy- d -glucose ([18F]FDG) for PET (Positron Emission Tomography) diagnosis. Cadmium isotopes contribute significantly to the total activity of generated impurities and, due to being potentially radiotoxic to living organisms, they should be effectively reduced from FDG to prevent accidental injection of even small concentrations into patients. Purification of the final [18F]FDG can be based on a set of columns, fulfilling various functions in the cleaning process. To assess cadmium impurities and the efficiency of the purification process, a low background gamma spectrometry system with high resolution has been applied. Even activity of 3.5 kBq and 290 kBq has been measured on QMA (Sep-Pak Light Accell Plus QMA) columns for 109Cd and 107Cd isotopes, respectively. 107Cd activity in the five column set was higher than that of 109Cd. The rate of 18F production process was about 1 GBq/min, while that of 107Cd and 109Cd radionuclides was about 4.2 kBq/min and 50 Bq/min respectively. The same purification efficiency of both isotopes has been obtained at each step of the process. The production rate of 107Cd and 109Cd radionuclides was insignificant compared to the 18F production rate. Therefore [18F]FDG final product for use in injections before PET diagnostics was efficiently purified from cadmium radionuclide impurities.

The influence of an effective spin—isospin interaction in the particle—particle channel on the beta-decay half-lives and multineutron-emission probabilities is studied. The contributions of tensor correlations and coupling of the one- and two-phonon configurations are taken into account within a self-consistent approach that relies on the quasiparticle random-phase approximation and which employs Skyrme interaction. The beta-decay properties of neutron-rich cadmium isotopes are calculated.

Flooding in paddy soils alters the soil redox of manganese (Mn) and produces elevated concentrations of soluble Mn that can reduce cadmium (Cd) uptake by rice. To better understand the fates of Mn and Cd, along with changes in soil redox conditions, we conducted microcosm incubations in paddy soil covering the reduction to oxidation to re-reduction phases. The extractable Cd concentration decreased rapidly during the reduction phases but increased upon oxidation, and Cd availability largely depended on soil pH, Eh, pe + pH, and the extractable Mn concentration. Exogenous Mn can promote Cd binding with Fe–Mn(oxyhydro)oxides. A trade-off effect between the soil-extractable Cd and Mn concentrations across changes in pH, Eh, pe + pH was identified, and attaining an optimal pe + pH value of 6.8 was targeted. Furthermore, to provide insights into how the redox status of Mn changes to alter Cd mobilization in a paddy soil-rice system, Cd isotope ratios across the paddy soil-rice tissue continuum were investigated using planted rhizobox experiments under different irrigation regimes. The heavy Cd isotopes from the soil to liquid-phase (Δ114/110Cdextract-soil = 0.40–0.82‰) and from the soil to rice grain (Δ114/110Cdgrain-soil = 0.84–0.89‰) were preferentially enriched. Light isotopes were likely to be enriched in Cd bound to Fe/Mn-oxides, a process that was promoted by increased Mn availability. These results suggest that Cd isotopes are systematically fractionated within the paddy soil–rice system, which is caused by the unsteady soil redox, and the stabilization of Cd in the bound soil pool such as Fe–Mn(oxyhydro)oxides-Cd under reducing conditions could be developed as a Cd retention mechanism in paddy soils.

The potential-energy surfaces (PESs) for ground states of even-even $^{102--112}\mathrm{Cd}$ isotopes are obtained by using the three-dimensional relativistic Hartree-Bogoliubov model with the density-dependent meson exchange interaction. The quadrupole deformation parameters are extracted from the PES calculations and employed in the beyond mean-field projected shell model to study the yrast and excited states of these isotopes. Besides, the $E2$ transition probabilities and $g$ factors are obtained and compared with the experimental data. The present calculations support the experimental finding that yrast ${8}^{+}$ states of light Cd isotopes are of ${(\ensuremath{\pi}{g}_{9/2})}^{2}$ character whereas the yrast ${10}^{+}$ states of medium-mass Cd isotopes are found to possess ${(\ensuremath{\nu}{h}_{11/2})}^{2}$ character.

International audience; Cadmium (Cd) isotopes are known to fractionate during complexation with various environmentally relevant surfaces and ligands. Our results, which were obtained using (i) batch experiments at different Cd concentrations, ionic strengths, and pH values, (ii) modeling, and (iii) infrared and X-ray absorption spectroscopies, highlight the preferential enrichment of light Cd isotopes bound to humic acid (HA), leaving the heavier Cd pool preferentially in the solution (Δ114/110CdHA-Cd(aq) of -0.15 ± 0.01‰). At high ionic strengths, Cd isotope fractionation mainly depends on its complexation with carboxylic sites. Outer-sphere complexation occurs at equilibrium together with inner-sphere complexation as well as with the change of the first Cd coordination and its hydration complexes in solution. At low ionic strengths, non-specific Cd binding induced by electrostatic attractions plays a dominant role and promotes Cd isotope fractionation during complexation. This significant outcome elucidates the mechanisms involved in HA-Cd interactions. The results can be used during (i) fingerprinting the available Cd in soil solution after its complexation with solid or soluble natural organic matter and (ii) evaluate the contribution of Cd complexation with organic ligands and phytoplankton-derived debris vs. Cd assimilation by phytoplankton in seawater.

A116Cd–106Cd double‐spike method in combination with thermal ionization mass spectrometry (TIMS) was applied to obtain cadmium (Cd) mass fractions and stable isotope compositions in seven biogenic certified reference materials (pine needles, tomato leaves, spinach leaves, lichen, mussel tissue, oyster tissue, and pig kidney). This sample set was supplemented by the analysis of two manganese nodules and one soil reference material for which the Cd isotopic data has already been reported. The intermediate measurement precision of the whole protocol as determined for the NIST SRM 3108 Cd standard solution yields an excellent value of δ114/110Cd of −0.005 ± 0.029‰ (2SD, n = 47). The Cd isotopic compositions of the biogenic materials, reported as δ114/110Cd relative to NIST SRM 3108, range from −0.52 to +0.50‰. Plants show δ114/110Cd mean values ranging from −0.09 to +0.45‰ whereas the δ114/110Cd value of −0.17‰ was detected in the lichen and the values of −0.51, −0.52, and +0.47‰ were gathered for the oyster, mussel, and pig kidney tissues, respectively. The observed large variation of the δ114/110Cd values in the biogenic reference materials indicates a potential to use the natural mass-dependent Cd isotope fractionation in environmental, biogeochemical, and physiological studies.

Nucleosynthetic isotope variations are well documented for refractory elements in meteorites and the Earth, while moderately volatile elements generally display homogeneous compositions. Cadmium is a moderately volatile element with eight stable isotopes generated by a variety of nucleosynthetic processes. To address the extent of the nucleosynthetic variability in moderately volatile elements, new high precision Cd isotope data are presented for bulk samples of six carbonaceous and one enstatite chondrite. In addition, we report the first Cd isotope results of sequential acid leachates for the CM2 chondrite Jbilet Winselwan. Our new Cd data displays nucleosynthetic homogeneity for bulk chondrites and acid leachates within analytical uncertainties, in agreement with results for other moderately volatile elements. This implies that Cd isotopes were efficiently homogenised prior to incorporation into planetary bodies. We propose that Cd never significantly condensed into dust in stellar environments, or alternatively that such Cd-bearing dust was efficiently destroyed and recycled in the interstellar medium. Our leachate data provides evidence for further homogenisation during thermal processing in the protoplanetary disk including parent body processing. The data shows that Cd in carbonaceous chondrites mainly resides in the more easily dissolved phases, most likely sulphides that were affected by aqueous alteration. Less than 1% of the total Cd was recovered in the final leach fractions that employed HF and mainly dissolve silicates and refractory oxides. Cadmium is susceptible to thermal neutron-capture effects due to the large neutron capture cross-section of 113Cd (∼20,000 barns). We report variations of up to −0.6 ± 0.3 for ε113Cd (internally normalised to 116Cd/111Cd) in bulk chondrites, which renders Cd a potential thermal neutron-capture monitor. Most neutron dosimeters, such as Pt, Os and Hf, are sensitive to neutron capture in the epithermal energy range and have applications mainly limited to lunar samples or iron and stony-iron meteorites. The additional use of Cd, susceptible to neutron capture in the thermal energy range, therefore provides a new tool to determine the exposure histories of stony meteorites in more detail. Our study demonstrates that thermal neutron-capture effects in carbonaceous and enstatite chondrites can produce resolvable effects and require attention when assessing nucleosynthetic isotope variations., Geochimica et Cosmochimica Acta, 274, ISSN:0016-7037, ISSN:1872-9533

We probe the $N=82$ nuclear shell closure by mass measurements of neutron-rich cadmium isotopes with the ISOLTRAP spectrometer at ISOLDE-CERN. The new mass of $^{132}\mathrm{Cd}$ offers the first value of the $N=82$, two-neutron shell gap below $Z=50$ and confirms the phenomenon of mutually enhanced magicity at $^{132}\mathrm{Sn}$. Using the recently implemented phase-imaging ion-cyclotron-resonance method, the ordering of the low-lying isomers in $^{129}\mathrm{Cd}$ and their energies are determined. The new experimental findings are used to test large-scale shell-model, mean-field, and beyond-mean-field calculations, as well as the ab initio valence-space in-medium similarity renormalization group.

Cadmium isotopic compositions in non-contaminated systems and anthropogenic sources of Cd generally have different isotopic signatures. Cadmium isotopes, as a novel tracer, can be useful for fingerprinting the anthropogenic Cd sources, providing a promising source tracing technique in environmental studies. This review presents: (i) analytical techniques for Cd isotopic composition; (ii) isotopic signatures of Cd derived from anthropogenic activities; (iii) isotopic compositions of Cd in the industrial-impacted environmental samples; (iv) cadmium isotopic fractionation induced by geochemical process. Finally, the perspectives of using Cd isotopic compositions in environmental studies are also briefly discussed.

This paper presents a new method for the separation of Sn and Cd from geological matrices followed by high-precision isotope analyses that include low abundance isotopes (

Remobilization of zinc (Zn) from shoot to grain contributes significantly to Zn grain concentrations and thereby to food quality. On the other hand, strong accumulation of cadmium (Cd) in grain is detrimental for food quality. Zinc concentrations and isotope ratios were measured in wheat shoots (Triticum aestivum) at different growth stages to elucidate Zn pathways and processes in the shoot during grain filling. Zinc mass significantly decreased while heavy Zn isotopes accumulated in straw during grain filling (Δ66 Znfull maturity-flowering = 0.21-0.31‰). Three quarters of the Zn mass in the shoot moved to the grains, which were enriched in light Zn isotopes relative to the straw (Δ66 Zngrain-straw -0.21 to -0.31‰). Light Zn isotopes accumulated in phloem sinks while heavy isotopes were retained in phloem sources likely because of apoplastic retention and compartmentalization. Unlike for Zn, an accumulation of heavy Cd isotopes in grains has previously been shown. The opposing isotope fractionation of Zn and Cd might be caused by distinct affinities of Zn and Cd to oxygen, nitrogen, and sulfur ligands. Thus, combined Zn and Cd isotope analysis provides a novel tool to study biochemical processes that separate these elements in plants.

Excitation functions were calculated for the α-particle induced reactions 115In(α,x)117mSn, 114Cd(α,n)117mSn, 116Cd(α,3n)117mSn and natCd(α,x)117mSn to analyse the production of the medically important 117mSn (T½ = 13.6 d). For calculations three nuclear model codes (i.e. TALYS, EMPIRE and ALICE-IPPE) were used and the results were compared with the available experimental data. For the most important reaction, 116Cd(α,3n)117mSn, evaluated data are presented. The yield and radionuclidic purity of 117mSn from each reaction are discussed.

The projected shell model framework has been employed to carry out a systematic study on the deformation systematics of E ( 2 1 + ) and E ( 4 1 + ) / E ( 2 1 + ) values, BCS subshell occupation numbers, yrast spectra, backbending phenomena and electromagnetic quantities in 114–128Cd isotopes. Present calculations reproduce the observed systematics of the E ( 2 1 + ) , R 42 and B ( E 2 ; 2 + → 0 + ) values for 114–128Cd isotopic mass chain and give the evidence that deformation increases as one moves from 114Cd to 118Cd, thereafter it decreases up to 126Cd. This in turn confirms 118Cd to be the most deformed nucleus in this set of isotopic mass chain. The emergence of backbending, decrease in B ( E 2 ) values and change in g-factors in all these isotopes are intimately related to the crossing of g-band by 2-qp bands.

Experimental results on the excitation of isomeric nuclear states in the reactions 111Cd(γ, γ′)111m Cd, 113In(γ, γ′)113m In, and 115In(γ, γ′)115m In studied by the activation method at photon energies of up to 8 MeV are presented. The respective experiments were performed at the LUE-8 linear electron accelerator of the Institute for Nuclear Research (INR, Moscow). A method for calculating cross sections per equivalent photon was developed with the aid of a simulation on the basis of the GEANT-4 code. The data obtained in this way are discussed from the point of view of the possibility of studying collective nuclear excitations of various multipolarity near the threshold.

9 pags., 7 figs., Quadrupole moments and charge radii in cadmium isotopes are studied from a microscopic perspective. The results obtained from self-consistent deformed Hartree-Fock+BCS calculations with Skyrme forces are compared with isomer and isotope shifts measured from high-resolution laser spectroscopy experiments. The microscopic calculations reproduce fairly well the main features observed in those isotopes that include the linear increase with the neutron number of the quadrupole moments of the 11/2¿ isomers, as well as the parabolic behavior of the mean-square charge radii difference between isomers and ground states., This work was supported by Ministerio de Ciencia, Innovación y Universidades MCIU/AEI/FEDER,UE (Spain) under Contract No. PGC2018-093636-B-I00.

The shape evolutions of the even-even cadmium isotopes $^{110--116}\mathrm{Cd}$ are investigated in this work. The giant monopole resonances built on different shape isomeric states are studied using the quasiparticle random phase approximation, which is implemented with a finite amplitude method. We find the local minima corresponding to the prolate, oblate, and triaxial-deformed isomeric states in the even-even cadmium isotopes. Their responses to external monopole perturbations are quite different. Larger deformation tends to make the energy of the giant monopole resonance to shift lower. It is well known that the density functional models have some difficulties in predicting the right positions of the monopole resonances in cadmium isotopes: the centroid energies always seem too large compared to the experimental results. Our calculations show the giant monopole resonances built on the $\ensuremath{\gamma}$ soft isomeric states in the cadmium isotopes have centroid energies even lower than the experimental measurements. Therefore, if the isomeric branching of these $\ensuremath{\gamma}$ soft isomeric states turns out to be prominent, isomer mixing may be a good explanation to the longstanding puzzle.

Aiming at investigating the nuclear structure and the evolution of the deformation in Z = 48 Cd nuclei, which have only two protons less than the Z = 50 magic Sn, we have carried out a microscopic study of negative-parity high-spin states of odd-mass 111-127 Cd nuclei using the theoretical framework of projected shell model (PSM). The results have been obtained for the deformation systematics of the first excited state $ E(15/2^-)$ , yrast energy ratios ( $ R_{2/1}$ , yrast spectra, band crossings, backbending phenomena and B(E2) transition probabilities. The present calculations have reproduced the observed nuclear-structure properties quite successfully. It turns out from the results that the gradual and weak deformation in the entire mass chain of the cadmium isotopes under study is intricately linked to the non-degenerate nature of the quasi-particle valence orbits near the Fermi level for neutrons, which hinders the onset of deformations in these isotopes at $ N\geq 60$ . These isotopes are found to have weak prolate deformation in their ground states, 117Cd being the most deformed. Some higher-spin states have also been predicted in this work for which experimental data is not available yet. B(E2) values have also been reported, for the first time, in this work and are open for their experimental verification.

Background: The even cadmium isotopes near the neutron midshell have long been considered among the best examples of vibrational nuclei. However, the vibrational nature of these nuclei has been questioned based on $E2$ transition rates that are not consistent with vibrational excitations. In the neighboring odd-mass nuclei, the $g$ factors of the low-excitation collective states have been shown to be more consistent with a deformed rotational core than a vibrational core. Moving beyond the comparison of vibrational versus rotational models, recent advances in computational power have made shell-model calculations feasible for Cd isotopes. These calculations may give insights into the emergence and nature of collectivity in the Cd isotopes.Purpose: To investigate the nature of collective excitations in the $A\ensuremath{\approx}100$ region through experimental and theoretical studies of magnetic moments and electromagnetic transitions in $^{111}\mathrm{Cd}$.Method: The spectroscopy of $^{111}\mathrm{Cd}$ has been studied following Coulomb excitation. Angular correlation measurements, transient-field $g$-factor measurements and lifetime measurements by the Doppler-broadened line shape method were performed. The structure of the nucleus was explored in relation to particle-vibration versus particle-rotor interpretations. Large-scale shell-model calculations were performed with the SR88MHJM Hamiltonian.Results: Excited-state $g$ factors have been measured, spin assignments examined, and lifetimes determined. Attention was given to the reported $5/{2}^{+}$ 753-keV and $3/{2}^{+}$ 755-keV states. The $3/{2}^{+}$ 755-keV level was not observed; evidence is presented that the reported $3/{2}^{+}$ state was a misidentification of the $5/{2}^{+}$ 753-keV state.Conclusions: It is shown that the $g$ factors and level structure of $^{111}\mathrm{Cd}$ are not readily explained by the particle-vibration model. A particle-rotor approach has both successes and limitations. The shell-model approach successfully reproduces much of the known low-excitation structure in $^{111}\mathrm{Cd}$.

Amaranth (Amaranthus mangostanus L.) has superior capability for accumulating cadmium (Cd) and has the potential to be used for phytoremediation of Cd contaminated soils. Iron (Fe) is chemically similar to Cd and may mediate Cd-induced physiological or metabolic impacts in plants. The purpose was to investigate the model of time-dependent and concentration-dependent kinetics of Cd absorption under Fe deficiency, understanding the physiological mechanism of Cd absorption in amaranth roots. The kinetic characteristics of Cd uptake by amaranth grown in Cd enriched nutritional solution with or without Fe addition and with methanol-chloroform, carbonyl cyanide 3-chlorophenylhydrazone (CCCP), and lanthanum chloride (LaCl3) were compared using 109Cd2+ isotope labeling technique. The results showed that Cd uptake was time-dependent and about 90–93% of uptake occurred during the first 150 min. The kinetics of Cd uptake showed that two stages were involved. The saturation stage fitted the Michaelis-Menten model when concentrations of Cd were lower than 12.71 μmol/L and then the absorption of Cd by roots was increased linearly during the second stage. Only linear absorption was observed with methanol-chloroform treatment while the metabolic inhibitor CCCP inhibited only the saturation absorption process, and the Ca channel inhibitor LaCl3 partially inhibited the two stages of absorption. These results indicated that the root absorption of 109Cd2+ was enhanced under Fe deficiency which induced more Fe transporters in the root cell membrane, and the Ca channel, apoplastic and symplastic pathways enhanced the Cd absorption in roots.

Numerous scientific reports have been published, in which reported levels of cadmium are clearly, or very likely to be, erroneous. Normally, biological samples have to be digested in order to separate cadmium from the organic matrix before analysis. The basic principle is that cadmium forms a stable red-colored complex with dithizone at alkaline pH levels and that this complex can be extracted into chloroform or carbontetrachloride. The nonspecific absorption can thus be measured and the signal proportional to the actual cadmium concentration is measured as the difference between the total and nonspecific absorption. Cadmium has a number of stable isotopes. Neutron irradiation yields new radioactive cadmium isotopes. Cadmium levels can be determined using various types of electrochemical methods, e.g., classic polarographic methods and the more developed differential pulse anodic stripping voltammetry, and selective ion electrodes. Different electrochemical methods are of particular value for measurement of cadmium in solutions.

A theoretical study of the cross sections of (n,p)reactions on Cadmium isotopes has been performed using the Hauser-Feshbach model, Weisskopf-Ewing model, Exciton model, Two-component exciton model and Geometry dependent hybrid model for the incident energies from the reaction threshold to 20MeV. Furthermore, the empirical formulae based on the different systematics at the energies near 14.5MeV were used for calculating the (n,p)nuclear cross sections. Finally, the results of the present paper are discussed and compared with the experimental cross sections and TENDL-2017 data found in the literature.

Spectrum of gamma-rays from nuclear reactions with fast neutrons on cadmium measured by the time-of-flight method is analyzed. Impact of neutrons re-scattered on the experimental facilities and surroundings down to thermal energies is considered for indoor experiments. New unfolding procedure is proposed and used for determination from experimental amplitude spectrum of the gamma spectrum induced by fast neutrons only. The flux of the thermal neutrons is estimated by MCNP code. Spectrum of gamma ray from Cd induced by fast neutrons is corrected and its systematical uncertainties are estimated. The re-calculated gamma-spectrum is smaller than previous one and in the energy range ∼ 3.5÷6.5 MeV the differences between these spectra can reach ∼ 30%. Two wide peaks are observed as before in exponentially dropping yield for gamma-ray energies near neutron separation energy (∼ 4.5÷10 MeV) but with lesser intensities.

Consumption of rice (Oryza sativa) grain is a major pathway by which humans are exposed to Cd, especially in non-smoking Asian populations. Although the stable isotope signatures of Cd offer a potential tool for tracing its sources, little is known about the isotopic fractionation of Cd across the entire soil-rice-human continuum. Cadmium isotope ratios were determined in field soils, rice grain, and human urine collected from two Cd-contaminated regions in southern China. Additionally, Cd isotopic fractionation in rice plants was investigated using two transgenic plants differing in Cd uptake and accumulation. Analysis of isotope ratios revealed a preferential enrichment of the heavy Cd isotopes from soil to rice grain (δ114/110Cdgrain-soil = +0.40‰) and from grain to urine (δ114/110Cdurine-grain = +0.40‰) in both regions. The first increase was mainly caused by partitioning between the soil solid phase and the soil solution, with heavier Cd preferentially enriching in the soil solution. Within the rice plant, we identified multiple processes that alter the isotope ratio, but the net effect throughout the plant was comparatively small. Cd fractionation in humans is presumably due to the preferential enrichment of heavier Cd isotopes by metal transporters DMT1 and ZIP8 (responsible for the absorption of Cd into body from the foods). These findings provide important insights into the Cd isotopic fractionation through the soil-rice-human continuum and are helpful for tracing the sources of Cd.

Cadmium (Cd) calcite coprecipitation experiments were conducted to constrain the possible Cd isotope fractionation mechanism under different conditions. The changes in Cd/Ca molar ratio, HCO3− concentration, addition of Mg2+, Na2EDTA, or ionic strength (INaNO3) did not affect the composition of the precipitation but resulted in substantial change in mineral morphology. Cd exhibited an apparent isotope fractionation in the process of coprecipitation with calcite, and the fractional coefficient αCaCO3-Cd(aq) was less than one, indicating that the solution is preferentially enriched in heavy isotopes. The Cd mainly existed in the form of Cd(H2O)62+ in the solution before the reaction and was dominated by Cd(NO3)2, CdNO3+, Cd(EDTA)2− at the end of the experiments. The different isotopic ratios of Cd between the liquid phase and the solid phase can be explained by changes in Cd speciation which have different bond lengths of Cd O. Expect for the experiments with Na2EDTA and high ionic strength, the measured isotope ratios under different conditions plotted around the theoretical Rayleigh fractionation curve. This demonstrates that Cd isotopes almost reach equilibrium with Cd-calcite coprecipitation under the different experiment conditions and the Cd isotope fractionation mechanism is closely related to the thermodynamic isotope fractionation. In the experiment with Na2EDTA and high ionic strength, the formation of Cd(EDTA)2− and ion occlusion at surface sites inhibit Cd2+ entering the calcite and the isotopes of the solid and liquid phases do not reach equilibrium. As the result, obtained experiment data shift from the Rayleigh fractionation curve indicating the Cd isotope fractionation mechanism is closely related to the kinetic isotope effect. In general, the study results indicate that the Cd/Ca molar ratio, ionic strength, HCO3−, Na2EDTA, and Mg2+ concentrations of the solution can cause Cd isotope fractionation in different degrees during Cd-calcite coprecipitation. Cd isotope ratios might potentially provide important information on Cd mobilization and transportation in groundwater environment.

Cd contamination in rice grains has become a topic of great concern because of the high health risks associated with the long-term consumption of Cd-contaminated rice. Identification of Cd sources in rice grains by scientific methods is important for controlling heavy metal pollution and protecting human health. Here, the Cd concentrations and Cd isotopic compositions of rice plants (root, stem, leaf, and grain) and topsoil, and possible pollution sources (agricultural fertilizers, industrial dust, and automobile exhaust) were analyzed using an instrument of inductively coupled plasma mass spectrometry (ICP-MS) and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The results showed variations in the Cd isotopes of different components of rice plants and the fractionation coefficient of rice grains relative to topsoil (Δ114/110Cdrice grains−topsoil = 0.25‰). The contributions of pollution sources to rice grains were realized by combining the Cd isotopic composition with an isotopic mixing model (Isosource). The analysis showed that all three possible pollution sources contributed to the Cd in the rice grains in the field, the average Cd contribution of industrial dust, agricultural fertilizers and automobile exhaust was 87%, 9%, and 4%, respectively. Our study provides a feasible method for the identification of pollution sources of Cd in rice grains at the field scale and demonstrates that Cd isotopic composition is one of the powerful tools to trace the pollution sources of Cd in crops.

The gamma-activation technique was used to measure the absolute yields of photonuclear reactions on the cadmium isotopes 106,108Cd. The results obtained in this way were compared with the results of the calculations based on the statistical model. For reactions on the isotope 108Cd, agreement between these theoretical and experimental results is good, but the experimental ratio of the yields of photoproton and photoneutron reactions on the isotope 106Cd differs substantially from its theoretical counterpart. The results of our present study are discussed from the point of view of the production of bypassed nuclei in the p-process of nucleosynthesis.

Physics letters / B 754, 288 - 293 (2016). doi:10.1016/j.physletb.2016.01.039, Published by North-Holland Publ., Amsterdam

Heavy metals pollutants are global concern due to their toxicities and persistence in the environment. Cd isotope signatures in soils and sediments change during weathering, and it remains unclear if Cd isotopes can effectively trace Cd sources in a riverine system. In this study, we investigate Cd concentration and its isotope compositions, as well as other heavy metals of sediments and related potential Cd sources in a riverine system. The results showed that the two river sediments evaluated were moderately polluted by Zn, Cr, and Cd, while the source samples (soil, sludge, waste, and raw materials) were seriously polluted by heavy metals derived from anthropogenic activities. According to comprehensive ecological risks, the two sediments have a moderate to low potential risk and more than half of all anthropogenic activities in the study area were at considerable or moderate potential risk. We determined that Cd pollution in river sediments was primarily derived from sewage treatment and outlets based on river flow direction and the isotope geochemical behaviors of the Cd isotope in nature conditions. This study further confirmed that analyzing Cd isotopes could be a powerful tool for tracing the source and destination of environmental Cd for multiple sources with similar Cd concentrations.

Anthropogenic activities, especially industrial production and agricultural practices have led to Cd accumulation in the agricultural soil locating near to the industrial areas of China threatening soil environmental quality and food security. In this study, the sources of Cd pollution were accurately analyzed, which may lead to efficiently control the Cd content in the soil. The samples of agricultural topsoil, four possible pollution sources such as smelter dust, automobile exhaust, cement factory dust and agricultural fertilizer were collected, and the Cd concentrations and Cd isotope ratios were analyzed using the instrument of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Multi-collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The results indicated that the Cd concentration of agricultural topsoil (11.72 ± 0.30 mg kg−1) was much higher than the recommended value (0.6 mg kg−1). The highest δ114/110CdNIST3108 value (−0.15 ± 0.14‰) was observed for smelter dust and the lowest δ114/110CdNIST3108 value (−0.64‰) was found in cement factory dust. Similarly, the highest Cd concentration was found in smelter dust and it was clearly distinguishable from the other samples based on δ114/110CdNIST108 values. Cd isotope analysis suggested that smelter along with agricultural fertilizer were the major sources of Cd accumulation in agricultural topsoil. In addition, based on the IsoSource software, the relative Cd contribution rates due to automobile exhaust, cement factory, agricultural fertilizer, and smelter dust were 14%, 7%, 20%, and 59%, respectively, demonstrating that smelter dust is the main pollution source of Cd in the study area. Cd isotope analysis is a promising tool to accurately identify the heavy metal pollution sources.

A method of deriving the Hamiltonian of the interacting boson model, that is based on the microscopic framework of the nuclear energy density functional, is presented. The constrained self-consistent mean-field calculation with a given energy density functional provides potential energy surface within the relevant collective coordinates, which is subsequently mapped onto the expectation value of the interacting-boson Hamiltonian in the boson condensate state. This procedure completely determines the strength parameters of the IBM, and the diagonalization of the mapped Hamiltonian yields excitation spectra and transition rates for a given nucleus. Two recent applications of the method are discussed, that is, the descriptions of the intruder states in Cadmium isotopes and the octupole correlations in neutron-rich odd-mass Barium isotopes., Comment: 6 pages, 7 figures; Talk given at the Nuclear Structure and Dynamics NSD2019, 13-17 May 2019, Venice, Italy

The relative response of neutron rem detectors has previously been shown to increase after prolonged exposure to a neutron flux. This increase has been referred to as the "soak factor." The cause of the increased response has been previously unexplained. This note reports on a search for the underlying cause of the increased response. Testing involved gamma-ray spectroscopy of activated neutron rem detector components and testing of instrument response at various rates of neutron flux and accumulated fluence. The proposed primary cause of the increased response is activation of copper in the brass collar at the fill end of the gas-filled detector tube. This component allows for attachment of the extension housing on the tube containing BF3 or He gas. Under a neutron flux, some of this copper activates to Cu. In addition, Mn was detected in activated components but does not seem to be a significant contributor to the detector response. Cadmium isotopes did not appear to be significant. The activated component causes an increase in indicated neutron dose rate due to decay photons from activated components. Photons normally have little impact on neutron rem detector readings because the electrical pulses produced in the probes are below the lower-level discriminator. However, the photon pulses do impact the overall count rate when they occur simultaneously with normally uncounted, lower amplitude, wall-effect neutron pulses.

The neutron-deficient cadmium isotopes have been measured by high-resolution laser spectroscopy at CERN-ISOLDE. The electromagnetic moments of $^{101}\mathrm{Cd}$ have been determined for the first time and the quadrupole-moment precision of $^{103}\mathrm{Cd}$ has been vastly improved. The results on the sequence of $5/{2}^{+}$ ground states in $^{101--109}\mathrm{Cd}$ are tentatively discussed in the context of simple structure in complex nuclei as similarities are found with the $11/{2}^{\ensuremath{-}}$ states in the neutron-rich cases. Comparison with shell-model calculations reveals a prominent role of the two holes in the $Z=50$ core.

A key question concerning the spherical-vibrator attributes of states in Cadmium isotopes is addressed by means of a boson Hamiltonian encompassing U(5) partial dynamical symmetry. The U(5) symmetry is preserved in a segment of the spectrum and is broken in particular non-yrast states, and the resulting mixing with the intruder states is small. The vibrational character is thus maintained in the majority of low-lying normal states, as observed in $^{110}$Cd., Comment: 6 pages, 1 figure, 2 tables, Physical Review C (Rapid Communication). arXiv admin note: text overlap with arXiv:1810.05917

The structure of even-even $^{108-116}$Cd isotopes is investigated based on the self-consistent mean-field approach. By mapping the quadrupole-$(\beta,\gamma)$ deformation energy surface, obtained from the constrained self-consistent mean-field calculations with a choice of the Skyrme force and pairing property, onto the Hamiltonian of the interacting boson model with configuration mixing, the strength parameters of the Hamiltonian are determined. The low-lying excitation spectra and electric quadrupole transition rates for the considered Cd nuclei are computed by the resultant Hamiltonian, and are compared in detail with the experimental data. Our semi-microscopic prediction identifies several intruder states as suggested empirically, and overall, provides a reasonable qualitative description of the experimental energy levels and transition rates., Comment: 9 pages, 4 figures, 4 tables

The irradiations of Ag to Sn targets by bremsstrahlung generated with 23-MeV electron beams are performed at the MT-25 microtron. Gamma spectra of the induced activities have been measured and the yields of all detected radionuclides and isomers are carefully measured and analyzed. A regular dependence of yields versus changed reaction threshold is confirmed. Many isomers are detected and the suppression of the production probability is observed with growing product spin. Special peculiarities for the isomer-to-ground state ratios were deduced for the 106mAg, 108mAg, 113mIn, 115mIn, and 123mSn isomers. The production of such nuclides as 108mAg, 115mIn, 117gIn, and 113mCd is of interest for applications, especially when economic methods are available.