The Experts below are selected from a list of 56616 Experts worldwide ranked by ideXlab platform
Wladyslaw Walkowiak - One of the best experts on this subject based on the ideXlab platform.
-
competetive transport of cobalt 60 Strontium 90 and cesium 137 radioisotopes across polymer inclusion membranes with dnns
Journal of Membrane Science, 2007Co-Authors: Cezary Kozlowski, Wladyslaw WalkowiakAbstract:Abstract Plasticized cellulose triacetate membranes with 3,7-dinonyl-naphtalene-1-sulfonic acid (DNNS) containing o -nitrophenyl pentyl ether (ONPPE) as the plasticizer were prepared for competitive transport of Cs-137, Sr-90, and Co-60 isotopes from aqueous solutions at concentration of 1.0 × 10 −7 M each and containing 0.10 M sodium nitrate. The receiving phase was 1.0 M HCl aqueous solution. The selectivity order of metal ions transported was found to be: Co(II) > Cs(I) > Sr(II). For optimal values of polymer inclusion membrane, i.e. 4.0 cm 3 per 1.0 g cellulose triacetate the recovery factors for Co(II), Cs(I), and Sr(II) after 72 h of transport were found to be 98%, 91% and 51%, respectively. The long term integrity of transport across polymer inclusion membrane was studied. To explain the mechanism of membrane transport the diffusion of metal ions complexes with DNNS in polymer inclusion membrane was also measured.
-
separation of cobalt 60 Strontium 90 and cesium 137 radioisotopes by competitive transport across polymer inclusion membranes with organophosphorous acids
Desalination, 2006Co-Authors: Cezary Kozlowski, Jolanta Kozlowska, Witalis Pellowski, Wladyslaw WalkowiakAbstract:Abstract The removal and separation of Co-60, Sr-90, and Cs-137 radioisotopes from nitrate aqueous solutions were studied by competitive transport across cellulose triacetate plasticized membranes using organophosphorous acids compounds (D2EHPA, Cyanex 272, Cyanex 301 and Cyanex 302). Competitive transport of trace radionuclides ions from 0.10 M NaNO 3 aqueous solutions across polymer inclusion membranes containing cellulose triacetate as the support, D2EHPA as the ion carrier and o -nitrophenyl pentyl ether as the plasticizer provide the selectivity order: Co(II) > Cs(I) > Sr(II). The affinities of the radioisotopes investigated for Cyanex 272 and Cyanex 302 follow the order Cs(I) > Sr(II) > Co(II). The influence of ion carrier acidity on cation transport selectivity and effectiveness was explored. The results show a linear decrease of permeability coefficient values for Co(II) with an increase of pK a values of ion carriers. A long-term transport experiment was carried out to demonstrate the durability of polymer inclusion membranes.
Yoshihiro Iwata - One of the best experts on this subject based on the ideXlab platform.
-
isotope shift and hyperfine structure measurements on triple resonance excitation to the autoionizing rydberg state of atomic Strontium
Journal of Quantitative Spectroscopy & Radiative Transfer, 2021Co-Authors: Yoshihiro Iwata, Masabumi Miyabe, Katsuaki Akaoka, Ikuo WakaidaAbstract:Abstract Triple resonance excitation to the autoionizing Rydberg state of atomic Strontium was studied for the isotope-selective photoionization of Strontium-90 ( 90 Sr). We investigated a new resonance ionization scheme, namely, 689.4 nm–472.4 nm–404.2 nm that is less affected by the multiphoton ionization induced by the first (689.4 nm) laser compared to the scheme in our previous study, namely, 689.4 nm–487.4 nm–393.8 nm. The isotope shifts and hyperfine structure constants of stable Sr isotopes were measured for the second and third transitions of these two schemes. Thus, the 90 Sr isotope shift for each of the four transitions was evaluated using the King plot analysis. Under the current laser conditions, no significant difference was observed in the measured 90 Sr optical isotopic selectivity between these two schemes, but the new scheme could show better selectivity if the first (689.4 nm) laser output is increased to improve the ionization efficiency. Our spectroscopic data will be useful for future analysis of 90 Sr in real samples and may also help promote studies in other fields, such as precision measurements using cold atoms in optical traps.
-
spectroscopic analysis of radioactive Strontium with low isotopic abundance using laser resonance ionization
Hyperfine Interactions, 2020Co-Authors: Yoshihiro Iwata, Donguk Cheon, Masabumi Miyabe, Shuichi HasegawaAbstract:Strontium-90 (90Sr, half-life of 28.8 years) is one of the major fission products released in the Fukushima Daiichi Nuclear Power Plant accident in Japan. Due to the high concentrations of Sr stable isotopes in marine products, an upper limit for 90Sr isotopic abundance in them is of the order of 1 ppb or less. Resonance ionization technique using narrow linewidth lasers is suitable for analysis requiring high elemental and isotopic selectivity. In this study, we have investigated on 689.4 nm - 487.4 nm - 393.8 nm three-step resonance ionization of Sr atoms, where the 90Sr isotope shifts in the second and third transitions were predicted using a King plot approach to evaluate the optical isotopic selectivity. As the first step in measuring real samples, the influence of coexisting elements in seawater was also derived.
K Stratmann - One of the best experts on this subject based on the ideXlab platform.
-
fast low level detection of Strontium 90 and Strontium 89 in environmental samples by collinear resonance ionization spectroscopy
Spectrochimica Acta Part B: Atomic Spectroscopy, 1993Co-Authors: L Monz, R Hohmann, H J Kluge, S Kunze, J Lantzsch, E W Otten, G Passler, P Senne, J Stenner, K StratmannAbstract:Environmental assessment in the wake of a nuclear accident requires the rapid determination of the radiotoxic isotopes 89Sr and 90Sr. Useful measurements must be able to detect 108 atoms in the presence of about 1018 atoms of the stable, naturally occurring isotopes. This paper describes a new approach to this problem using resonance ionization spectroscopy in collinear geometry, combined with classical mass separation. After collection and chemical separation, the Strontium from a sample is surface-ionized and the ions are accelerated to an energy of about 30 keV. Initially, a magnetic mass separator provides an isotopic selectivity of about 106. The ions are then neutralized by charge exchange and the resulting fast Strontium atoms are selectively excited into high-lying atomic Rydberg states by narrow-band cw laser light in collinear geometry. The Rydberg atoms are then field-ionized and detected. Thus far, a total isotopic selectivity of S > 1010 and an overall efficiency of ξ = 5 × 10−6 have been achieved. The desired detection limit of 108 atoms 90Sr has been demonstrated with synthetic samples.
S K Sahoo - One of the best experts on this subject based on the ideXlab platform.
-
Measurement of Strontium-90 in Japanese soil samples after the Fukushima nuclear accident
2019Co-Authors: Kavasi Norbert, S K Sahoo, Arae Hideki, Yoshida SatoshiAbstract:The cooling systems of the nuclear reactors were damaged by a devastating tsunami that hit the Fukushima Daiichi Nuclear Power Plant, Japan, which resulted in a nuclear major accident (Level 7 of the International Nuclear and Radiological Event Scale) with intercontinental radioactive contamination. Among the released radionuclides, pure β-particle emitter fission products, such as 89Sr (T1/2 50.5 d) and 90Sr (T1/2 28.8 y) occurred. RadioStrontium is one of the most biologically hazardous radionuclides, consequently environmental monitoring to reveal the contaminated areas in Japan is essential. As radioactive contamination of 90Sr already exists in Japan originating from nuclear weapon testing, a measurement method with a low detection limit is necessary.In our work different soil samples collected from Fukushima, Chiba and Okinawa prefectures were analysed for 90Sr measurement.The soil samples were digested by open chemical method using concentrated HF, HNO3 and HCl acids. The Strontium was chemically separated using extraction chromatography resin (Sr resin). Liquid scintillator counting system was used for 90Sr detection.The 90Sr activity concentrations in the soil samples were between 5 and 25 Bq/kg demonstrating low contamination compared to the Chernobyl accident and atmospheric nuclear weapon tests.International Symposium on Radiological Issues for Fukushima\u27s Revitalized Futur
-
Strontium 90 activity concentration in soil samples from the exclusion zone of the fukushima daiichi nuclear power plant
Scientific Reports, 2016Co-Authors: S K Sahoo, Norbert Kavasi, Atsuyuki Sorimachi, Hideki Arae, Shinji Tokonami, J W Mietelski, Edyta łokas, Satoshi YoshidaAbstract:The radioactive fission product 90Sr has a long biological half-life (˜18 y) in the human body. Due to its chemical similarity to calcium it accumulates in bones and irradiates the bone marrow, causing its high radio-toxicity. Assessing 90Sr is therefore extremely important in case of a nuclear disaster. In this work 16 soil samples were collected from the exclusion zone (<30 km) of the earthquake-damaged Fukushima Daiichi nuclear power plant, to measure 90Sr activity concentration using liquid scintillation counting. 137Cs activity concentration was also measured with gamma-spectroscopy in order to investigate correlation with 90Sr. The 90Sr activity concentrations ranged from 3.0 ± 0.3 to 23.3 ± 1.5 Bq kg−1 while the 137Cs from 0.7 ± 0.1 to 110.8 ± 0.3 kBq kg−1. The fact that radioactive contamination originated from the Fukushima nuclear accident was obvious due to the presence of 134Cs. However, 90Sr contamination was not confirmed in all samples although detectable amounts of 90Sr can be expected in Japanese soils, as a background, stemming from global fallout due to the atmospheric nuclear weapon tests. Correlation analysis between 90Sr and 137Cs activity concentrations provides a potentially powerful tool to discriminate background 90Sr level from its Fukushima contribution.
Satoshi Yoshida - One of the best experts on this subject based on the ideXlab platform.
-
Strontium 90 activity concentration in soil samples from the exclusion zone of the fukushima daiichi nuclear power plant
Scientific Reports, 2016Co-Authors: S K Sahoo, Norbert Kavasi, Atsuyuki Sorimachi, Hideki Arae, Shinji Tokonami, J W Mietelski, Edyta łokas, Satoshi YoshidaAbstract:The radioactive fission product 90Sr has a long biological half-life (˜18 y) in the human body. Due to its chemical similarity to calcium it accumulates in bones and irradiates the bone marrow, causing its high radio-toxicity. Assessing 90Sr is therefore extremely important in case of a nuclear disaster. In this work 16 soil samples were collected from the exclusion zone (<30 km) of the earthquake-damaged Fukushima Daiichi nuclear power plant, to measure 90Sr activity concentration using liquid scintillation counting. 137Cs activity concentration was also measured with gamma-spectroscopy in order to investigate correlation with 90Sr. The 90Sr activity concentrations ranged from 3.0 ± 0.3 to 23.3 ± 1.5 Bq kg−1 while the 137Cs from 0.7 ± 0.1 to 110.8 ± 0.3 kBq kg−1. The fact that radioactive contamination originated from the Fukushima nuclear accident was obvious due to the presence of 134Cs. However, 90Sr contamination was not confirmed in all samples although detectable amounts of 90Sr can be expected in Japanese soils, as a background, stemming from global fallout due to the atmospheric nuclear weapon tests. Correlation analysis between 90Sr and 137Cs activity concentrations provides a potentially powerful tool to discriminate background 90Sr level from its Fukushima contribution.
