Cesium Absorption Research Articles

Basic Test about Absorption of Cesium and Strontium on Fly Ash Zeolite Synthesized by Microwaves

Basic Test about Absorption of Cesium and Strontium on Fly Ash Zeolite Synthesized by Microwaves

Production method of environmental tracer 132Cs by accelerator-based neutron

Cesium-132 has proposed as an alternative tracer of 137Cs for environment study on radioactive cesium dynamics released by a nuclear power plant accident. In the present study, we conducted a production experiment of the 132Cs by means of accelerator-based neutron method to investigate production amount and radioactive purity. A 12-g Cs2CO3 sample was irradiated by the accelerator-based neutron via the C(d,n) reactions by 1.2 µA of 30-MeV deuterons. As a result, 102 kBq/g of 132Cs was obtained with higher than 98.5% radioactive purity. Following that, a feasibility study of cesium dynamics measurement in andosol soil was performed. We found distribution of absorption of cesium in andosol soil can be clearly measurable by the produced 132Cs tracer.

Development of Filter-Type Adsorbent Containing Prussian Blue for Adsorption of Cesium in Aqueous Phase

This study aims to develop filter-type absorbent material containing Prussian blue in order to selectively absorb and remove cesium in water. Polyvinyl alcohol sponges (PVA) and cellulose filters (CF) were selected as supporting materials for Prussian blue. Three preparation methods of chemical (A), chemical/physical (B) and physical (C) were selected to immobilize Prussian blue on the material. As a result, the optimum synthesis method is a chemical/ physical method, and PVA was more suitable as a supporting material due to its porous nature. The morphology of the selected PVA-B material was investigated by scanning with an electron microscope, and it was confirmed that Prussian blue had formed in the pores of PVA. Isothermal absorption experiments were carried out to evaluate cesium absorption behaviors. The Freundlich isotherm absorption model showed a better fit with experimental results, which confirms that physical absorption and multi-layer absorption were dominant. The maximum absorption amount was calculated as 1.637 mg/g. Although the maximum absorption amount of cesium was not superior, it is considered to be an economical material suitable for mass production because of simplicity of synthesis and low manufacturing cost. Key words: Prussian Blue, Cesium, Polyvinyl Alcohol Sponge, Cellulose Filter

Study on Cesium Adsorption/Desorption Behavior of Porous Nickel

A simplified two-dimensional mode of is established for the performance, characteristics and transportation behavior in cesium adsorption/desorption process. Subsequently the cesium absorption/ desorption ability of porous nickel were investigated by batch experiment on the condition that the pressure is lower than 10 Pa in self-made quarz vacuum device containing porous nickel with the appropriate structural features and parameters simulated above. The experiment results indicate that about 95% of cesium can be desorbed quickly and effectively with a stable process from the porous nickel show that the simulation model and the analysis method are correct and feasible which can be used as a basis for further study. According to the detailed simulation result, model reveal the considered porous nickel could be used for feasibility of cesium adsorption/desorption, which is fully meeting the application need of both higher storage capacity and stable desorption efficiency in lower pressure ambient condition.

Absorption and translocation of cesium through Konara oak (Quercus serrata) bark

ABSTRACT Bark–wood translocation has been suggested as an important route for the contamination of trees via radiocesium in the initial stage of deposition. In this study, we investigated the cesium absorption through bark of mature Konara oak (Quercus serrata). Stable Cs (133Cs) was applied onto the bark at 1.2 m, and then after 8 weeks, the 133Cs concentration was determined in the outer bark, inner bark, sapwood, and heartwood of stem disks at several heights, as well as in the current-year leaves and branches from the tree tops. At the height of 1.2 m, the 133Cs concentration was significant higher in the sapwood of the treated trees than in those of the control trees. However, no difference was found in the 133Cs concentration in the heartwood of the treated and control trees not only in the wood above and below 1.2 m but also at 1.2 m. There was no significant difference in the 133Cs concentration of the current-year leaves and branches of the treated and control trees. Our results suggest that Cs absorption through bark may occur even in the dormant period of tree and the absorption is probably independent of cambial activities.

Effect of soil exchangeable potassium content on cesium absorption and partitioning in buckwheat grown in a radioactive cesium-contaminated field

The effect of soil exchangeable (plant-available) potassium (ExK) content on cesium (Cs) absorption and translocation in buckwheat was evaluated in a field contaminated with radioactive Cs (134Cs and 137Cs, RCs) in 2013. The RCs concentration in buckwheat was significantly positively correlated with the naturally occurring stable Cs (133Cs, SCs) concentration, and was lower at higher soil ExK content. The RCs and SCs were actively absorbed by buckwheat until the flowering stage. The soil ExK content was significantly negatively correlated with soil exchangeable RCs and SCs (ExRCs and ExSCs) concentrations. Greater RCs and SCs absorption by buckwheat in soils with low ExK contents was mainly due to higher soil ExRCs and ExSCs concentrations. Reproductive organs showed the largest differences in SCs concentration between low-ExK and high-ExK plots. The root–shoot and shoot–reproductive organs translocations of SCs markedly decreased with increasing soil ExK content. In the root–shoot and shoot–reproductive organs translocations, the discrimination of SCs and K decreased with decreasing soil ExK content. Our main findings were as follows: (1) because RCs are mainly taken up at the earlier growth stage, potassium should be applied as a basal fertilizer to decrease the RCs concentration in buckwheat; (2) lower soil ExK content led to higher soil ExRCs concentrations, resulting in greater RCs absorption by buckwheat; (3) the high Cs absorption and translocation and weaker discrimination between Cs and K in low ExK content soil may be due to the expression of K transporter(s) with weak discrimination between Cs and K.

Verifying thermodynamic equilibrium of molecular manifolds: Kennard-Stepanov spectroscopy of a molecular gas

The degree of thermalization of electronically excited state manifolds of an absorber can be tested via optical spectroscopy. In the thermalized-manifold case, the ratio of absorption and emission is expected to follow a universal Boltzmann-type frequency scaling, known as the Kennard-Stepanov relation. Here, we investigate absorption and emission spectral profiles of rubidium, cesium, and potassium molecular dimers in a high-pressure argon buffer-gas environment and study the effect of collisionally induced redistribution. We find that, despite the use of nonlinear excitation techniques, the ratio of absorption and emission well follows the Kennard-Stepanov scaling for a variety of molecular transitions. We conclude that the upper electronic state rovibrational manifold of the molecular gas is well in thermodynamic equilibrium. Further, we demonstrate an accurate, calibration-free determination of the gas temperature from the measured spectroscopic data.

Cesium absorption through bark of Japanese cedar (Cryptomeria japonica)

Absorption of radiocesium (137Cs and 134Cs) through bark, and its subsequent translocation into wood and needles, has been suggested as a potential source of tree contamination, but the process is not well understood. Field experiments were conducted to confirm whether Cs could enter a Japanese cedar tree through the bark and how Cs moves within a tree. Stable Cs (133Cs) was applied to the bark at 1.2-m height on 10- and 26-year-old Japanese cedars. The 133Cs concentrations were determined in the bark, sapwood, and heartwood (for 26-year-old cedar only) of stem disks from several heights, as well as in current-year needles from the canopy. The 133Cs concentrations were considerably higher in the sapwood and heartwood of stem disks from 1.2-m height in treated trees than in untreated trees, suggesting that 133Cs penetrated the bark to enter the wood. The average 133Cs concentrations were higher in the heartwood than the sapwood, indicating 133Cs accumulation in the heartwood. High 133Cs concentrations in the needles of treated trees implied acropetal movement of 133Cs to actively growing organs. Our results demonstrate that Cs can enter Japanese cedar trees through the bark and that Cs is transported radially to the heartwood and vertically to the apex.

Cesium absorption through bark of three tree species in Fukushima

Cesium absorption through bark of three tree species in Fukushima

Influence of copper, cobalt and iodine microelements on the exchange of 137Cs in the cows organisms at different physiological states

Aim. To estimate the impact of additions of different doses of copper, cobalt and iodine salts to the diet of dry and lactating cows on the absorption and removal of 137 Сs from the organism. Methods. Four groups of black and white breed cows –– were selected for the study on the farm in Narodychi district of Zhytomyr region following the traditional methods. The animals were fed salts of microelements with concentrated feedstuffs. Specifi c radioactivity of feedstuffs, feces, urine, milk was defi ned by the gamma-spectrometry method using AMA-OZF analyzer. Results. During the dry period the content of 137 Сs in nutrition of cows of experimental groups was almost the same, whereas its removal from the organism of animals was different depending on the impact of microelements on the degree of radionuclide absorption. The exceeding of the norms of copper and cobalt by 30 % and iodine – by 70 % promotes the decrease of “visible” absorption of cesium and enhances its removal due to the radionuclide, accumulated in the tissues. The radioactivity of the diet of animals dur- ing lactation increased considerably (22–26-fold) and amounted to 17–22 kBq per day; at the same time high bioavailability of the radionuclide was revealed. The increase in 137 Cs content in the diet of cows during the grazing period is related to the use of contaminated fi elds. In May specifi c radioactivity of cow milk was the lowest; its insignifi cant increase (50–65 Bq/l) was observed in June, July and August. The radioactivity of cow milk in September and October increased considerably (150–184 Bq/l). The fortifi cation of the diet of animals of the 3 rd experimental group with copper, cobalt, and iodine promoted the decrease in the radioactivity of cow milk comparing the cow milk of the 1 st experimental group and the milk of the 4 th experimental group. During the lactation period the least absorption of the radionuclide was revealed for the normative consumption of all the microelements, and the highest – for the increased consumption of cobalt only. Conclusions. The vegeta- tive feedstuffs of dairy cattle in Polissia provides the requirement of cobalt for 30–35 %, iodine – for 25–30 %, copper – for 70 % in winter, and during the grazing period in summer – for 25, 35, and 60 % respectively. The fortifi cation of the diet of cows with microelements promotes the decrease in the absorption of 137 Сs in the gastrointestinal tract and its reduced transfer into cow milk.

市販防虫ネットを利用した陸生藍藻イシクラゲNostoc communeによる 放射性セシウムの吸収・固定法の効率化

市販防虫ネットを利用した陸生藍藻イシクラゲNostoc communeによる 放射性セシウムの吸収・固定法の効率化

Study on sensitivity-related parameters of distributed feedback laser-pumped cesium atomic magnetometer

This article reports a distributed feedback (DFB) laser-pumped cesium atomic experimental magnetometer, showing how the sensitivity is influenced by the following 5 kinds of parameters: laser light intensity, laser frequency, radiofrequency intensity, temperature of cesium absorption cell, and the pressure of the buffer gas in the cell. Results of the experiments show that each of the five parameters has some influence on the sensitivity of the magnetometer, especially the laser frequency, radiofrequency intensity, and temperature of cesium absorption cell, which can even improve the sensitivity by 10 times. Recently we have obtained a sensitivity of 2.5 pT/Hz1/2.

Radiocesium accumulation in Egeria densa, a submerged plant – possible mechanism of cesium absorption

Radioactive cesium (Cs) was discharged into the environment in the northeast region of Japan after destruction of the nuclear power station in March 2011. In this work, we study the uptake and accumulation of Cs in a freshly submerged vascular plant, Egeria densa (Brazilian waterweed, Hydrocharitaceae), to investigate the behavior of Cs in the aquatic ecosystem and to predict the movement of the radionuclide to remove this Cs from the environment. We collected plants, waters, and sediments that had been contaminated by radioactive fallout in Fukushima Prefecture in September 2012. The activities of 134Cs, 137Cs, and 40K were measured using a germanium semiconductor detector. We found that the endogenous radioactive Cs concentrations in plants were correlated with those in the sediments. To discuss the uptake mechanism of Cs, stable 133Cs was applied separately to shoots and roots in a two-compartment bath. The results showed that the environmental Cs transferred to both shoot and root parts in plants. To analyze the detailed localization of Cs in plants, synchrotron radiation-based micro X-ray fluorescence (SR-μ-XRF) analysis was performed for the plants cultivated in a hydroponic medium containing 133Cs. The two-dimensional metal distribution of leaves was determined by μ-XRF with approximately 0.7 μm X-ray beams. The distribution showed the predominant localization of Cs, K as well as several divalent metals in the cell wall or apoplastic regions, suggesting the possible absorption mechanism of Cs in the plants. We concluded that E. densa plays an important role in the deposition of radioactive Cs in fresh water.

加工用トマトの放射性セシウム吸収に関与する因子の解析

土壌の交換態放射性セシウム濃度と土壌の交換態カリウム濃度が，トマトの放射性セシウム吸収に関与する重要な因子であることを明らかにした。2011年夏に，福島第一原子力発電所から半径100km圏内の14試験圃場で，加工用トマトの放射性セシウム移行係数及び，吸収に関与する因子を調査した。放射性セシウム移行係数は0.00031～0.0072で，圃場ごとで異なった。土壌の交換態放射性セシウム濃度と果実の放射性セシウム濃度に正の相関(r＝0.77，p＜0.01)が，土壌の交換態カリウム濃度と果実への放射性セシウム移行係数に，負の相関(ρ＝－0.65，p＜0.05)が認められた。重回帰分析の結果，土壌の交換態放射性セシウム濃度，土壌の交換態カリウム濃度で果実の放射性セシウム濃度(Y)の73％を説明できることがわかった。カリウム1.5倍増肥区と慣行施肥区の移行係数を比較した結果，土壌の交換態カリウム濃度が低い圃場でのみ，カリウム増肥で移行係数が低下した。以上の結果から，土壌の交換態放射性セシウム濃度と交換態カリウム濃度は，トマトの放射性セシウム吸収に関与する重要な因子であることがわかった。また，土壌の交換態カリウム濃度が低い圃場ではカリウムを増肥することで，放射性セシウム吸収量を低減できることが示唆された。

Ability of phytoremediation for absorption of strontium and cesium from soils using Cannabis sativa

Aims: This study is aimed at assessing the effectiveness of Cannabis sativa in the absorption of cesium and strontium elements from the soil. Materials and Methods: This study was conducted in 2011, in Tehran, Iran. We employed the phytoremediation technology to refine the contamination of soil with radioactive material such as cesium and strontium. Cannabis sativa was selected because of its capability for potential radioactive absorption. It was planted in various soils with different concentrations of cesium and strontium (20 ppm, 40 ppm, 60 ppm, and 80 ppm), and after sufficient growth for about six months, it was separated into root, stem, and leaves for measuring the absorption of these elements in the main parts of the plant. The samples were measured by using the Inductively Coupled Plasma (ICP) method. Results: Strontium absorption and the main parts of the plant showed a significant relationship. The percentage of strontium absorption was 45% in the root, 40% in the stem, and the minimum absorption was found in the leaves (15%), but the corresponding figure was not significant for the cesium element. A strontium concentration of 60 ppm was possibly the maximum absorption concentration by Cannabis. Conclusion: Our findings suggest that strontium can be absorbed by Cannabis sativa, with the highest absorption by the roots, stems, and leaves. However, cesium does not reach the plant because of its single capacity and inactive complex formation.

二番茶生育期間中の茶樹におけるセシウムの吸収・移行について

二番茶生育期間中の茶樹におけるセシウムの吸収・移行について

X-ray atomic absorption of cesium and xenon in theL-edge region

X-ray absorption of atomic cesium is measured in the $L$-edge region, using a beryllium-window cell for cesium vapor. For comparison, absorption in Xe gas in the same energy region is remeasured with improved signal-to-noise ratio. By combining deconvolution and modeling, the edge profiles are studied to determine the threshold energies and the shape of the edge apex with exponential slope of the high-energy flank. In both elements, multielectron excitations show the same basic ordering in compact groups, largely independent of the core-hole subshell, following the energy sequence of coexcited valence and subvalence orbitals. The main effect of $6s$ electron in Cs, apart from $2(s,p)6s$ excitation, is the enhancement of single- as well as some multielectron resonant channels. The spectra of both elements show the ``polarization effect'': a convex basic curvature of the ${L}_{2}$ and ${L}_{3}$ segments, a concave ${L}_{1}$ segment. Previously, Kutzner demonstrated a convincing theoretical explanation of the effect on Xe in a relativistic random-phase approximation with relaxation involving overlap integrals with continuum [Rad. Phys. Chem. 70, 95 (2004)].

Measurement uncertainty and temporal resolution of Doppler global velocimetry using laser frequency modulation

A Doppler global velocimetry (DGV) measurement technique with a sinusoidal laser frequency modulation is presented for measuring velocity fields in fluid flows. A cesium absorption cell is used for the conversion of the Doppler shift frequency into a change in light intensity, which can be measured by a fiber coupled avalanche photo diode array. Because of a harmonic analysis of the detector element signals, no errors due to detector offset drifts occur and no reference detector array is necessary for measuring the scattered light power. Hence, large errors such as image misalignment errors and beam split errors are eliminated. Furthermore, the measurement system is also capable of achieving high measurement rates up to the modulation frequency (100 kHz) and thus opens new perspectives to multiple point investigations of instationary flows, e.g., for turbulence analysis. A fundamental measurement uncertainty analysis based on the theory of Cramér and Rao is given and validated by experimental results. The current relation between time resolution and measurement uncertainty, as well as further optimization strategies, are discussed.

New approach of fabrication and dispensing of micromachined cesium vapor cell

We describe the fabrication of wafer-scale alkali vapor cells based on silicon micromachining and anodic bonding. The principle of the proposed micromachined alkali cell is based on an extremely compact sealed vacuum cavity of a few cubic millimeters containing caesium vapors, illuminated by a high-frequency modulated laser beam. The alkali cells are formed by sealing an etched silicon wafer between two glass wafers. The technique of cell filling involves the use of an alkali dispenser. The activation of cesium vapors is made by local heating of the dispenser below temperature range causing degradations of cesium vapor purity. Thus, the procedure avoids negative effects of cesium chemistry on the quality of cell surfaces and sealing procedure. To demonstrate the clock operation, cesium absorption as well as coherent population trapping resonance was measured in the cells.

Diode-pumped 10 W continuous wave cesium laser

An efficient cesium vapor laser pumped with a continuous wave laser diode array has been demonstrated. The linewidth of the pump source was narrowed using the external cavity to match it to the cesium absorption line. The output power of the continuous wave cesium laser was 10 W, which exceeds previous results by more than a factor of 10, and the slope efficiency was 68%. The overall optical efficiency was 62%, which is a factor of 6 higher than previous pulsed laser results for alkali lasers with diode laser array pumping.