WorldWideScience

Sample records for caesium

  1. Structure of caesium selenate

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga, F.J.; Breczewski, T. (Universidad del Pais Vasco, Bilbao (Spain). Dept. de Fisica de la Materia Condensada); Arnaiz, A. (Universidad del Pais Vasco, Bilbao (Spain). Dept. de Quimica Inorganica)

    1991-03-15

    Cs{sub 2}SeO{sub 4}, M{sub 4}=408.77, orthorhombic, Pnam, a=8.3777 (8), b=11.276 (2), c=6.434 (2) A, V=607.8 (2) A{sup 3}, Z=4, D{sub x}=4.46 Mg m{sup -3}, MoK{alpha}, {lambda}=0.71069 A, {mu}=185.06 cm{sup -1}, F(000)=704, T=293 K, R=0.048, 3348 observed reflections. Average values of the Se-O and Cs-O distances are 1.637 (4) and 3.387 (3) A, respectively (range 3.038 (5)-3.872 (6) A with 9 and 11 coordination of caesium by oxygen). (orig.).

  2. Formulation of caesium based and caesium containing geo-polymers

    Energy Technology Data Exchange (ETDEWEB)

    Berger, S.; Joussot-Dubien, C.; Frizon, F. [CEA Valrho, Dir. de l' Energie Nucleaire, DEN, Decontamination and Conditioning Department, DEN/DTCD/SPDE/L2ED, 30 - Marcoule (France)

    2009-10-15

    Cement encapsulation is widely used as a low- and intermediate level radioactive waste immobilisation process. Among these wastes, caesium ions are poorly immobilised by Portland cement based materials. This work consists of an experimental investigation into the ability of geo-polymers to effectively encapsulate this chemical species and to determine the impact of caesium incorporation on the geo-polymer properties. Geo-polymers were synthesised with several compositions based on the activation of metakaolin with an alkali hydroxide solution containing caesium. The setting time, mineralogy, porosity and mechanical properties of the samples were examined for one month. Leach tests were conducted during the same period to determine the immobilisation efficiency. The results depend to a large extent on the composition of the activation solution in terms of soluble silica content and alkali used. These parameters determine both the degree of condensation and the geo-polymer composition. (authors)

  3. Electrokinetic removal of caesium from kaolin.

    Science.gov (United States)

    Al-Shahrani, S S; Roberts, E P L

    2005-06-30

    Soil, in the form of kaolin and a sample of natural soil from an industrial site, was artificially contaminated with caesium and subjected to electrokinetic treatment. The effect of catholyte pH control on the process was investigated using different acids to control the catholyte pH. During treatment the in situ pH distribution, the current flow, and the potential distribution were monitored. At the end of the treatment the pore fluid conductivity and the caesium concentration distribution was measured. The results of these experiments showed that for caesium contamination, catholyte pH control is essential in order to create a suitable environment throughout the soil to enable contaminant removal. It was found that the type of acid used to control the catholyte pH affected the rate of caesium removal (nitric, sulphuric, acetic and citric acids were tested). All of the acids tested were effective, but the highest caesium extraction was achieved when nitric acid was used to control the catholyte pH. The relatively high adsorption capacity of the soil for caesium was found to significantly reduce the rate of removal. After 240 h of treatment at 1 Vcm(-1) (using sulphuric acid to control the catholyte pH), less than 80% of the caesium was removed from a 30 cm long sample of kaolin. Electrokinetic treatment of the industrial soil sample was slower than for the kaolin, but a significant extraction rate for caesium was achieved.

  4. Confining caesium in expanded natural Perlite

    OpenAIRE

    Rehspringer, Jean Luc; Balencie, J.; Vilminot, Serge; Burger, Didier; Boos, Anne; Estournès, Claude

    2007-01-01

    International audience; We present the potential use of expanded perlite, a metastable amorphous hydrated aluminum silicate, as a permanent medium for the long-term confinement of caesium. A simple loading by mixing an aqueous caesium nitrate solution and expanded perlite at 300K followed by thermal annealing leads to 96% sintering. The formation of pollucite, CsAlSi2O6, a naturally occurring mineral phase, appears as the crystalline phase embedded in a glassy phase. Leaching tests on the res...

  5. Structure of caesium disulfate at 120 and 273 K

    DEFF Research Database (Denmark)

    Ståhl, Kenny; Berg, Rolf W.; Eriksen, Kim Michael

    2009-01-01

    The crystal structures of Cs2S2O7 at 120 and 273 K have been determined from X-ray single-crystal data. Caesium disulfate represents a new structure type with a uniquely high number of independent formula units at 120 K: In one part caesium ions form a tube surrounding the disulfate ions, [Cs8(S2O7......)6+]n; in the other part a disulfate double-sheet sandwiches a zigzagging caesium ion chain, [Cs2(S2O7)6−]n. Caesium disulfate shows an isostructural order–disorder transition between 230 and 250 K, where two disulfate groups become partially disordered above 250 K. The Cs+-ion arrangement shows...

  6. Caesium tetramethylammonium dodecahydrido-closo-dodecaborate monohydrate

    Directory of Open Access Journals (Sweden)

    Ioannis Tiritiris

    2016-02-01

    Full Text Available In the crystal structure of the hydrated double salt, Cs+·[N(CH34]+·[B12H12]2−·H2O, the asymmetric unit contains one caesium and one tetramethylammonium cation, one dodecahydrido-closo-dodecaborate anion and one water molecule. The Cs+ cation is coordinated tetrahedrally by four [B12H12]2− clusters, with the water molecule completing the coordination sphere. The tetramethylammonium cation is surrounded distorted octahedrally by six [B12H12]2− anions. The crystal structure is stabilized by a three-dimensional network of O—H...H—B and C—H...H—B dihydrogen bonds.

  7. Low Level Caesium Mapping in Latvia Anno 1996

    DEFF Research Database (Denmark)

    Aage, Helle Karina

    1999-01-01

    In Latvia the caesium-137 contamination from the Chernobyl accident and from the nuclear weapon tests in the 1960´es is very low. Conventional techniques for extracting information from the measured spectra cannot be used here. Therefore a new, sensitive technique - the pseudo concentration method...

  8. Low Level Caesium Mapping in Latvia Anno 1995

    DEFF Research Database (Denmark)

    Aage, Helle Karina

    1999-01-01

    In Latvia the caesium-137 contamination from the Chernobyl accident and from the nuclear weapon tests in the 1960´es is very low. Conventional techniques for extracting information from the measured spectra cannot be used here. Therefore a new, sensitive technique - the pseudo concentration method...

  9. The removal of caesium ions using supported clinoptilolite.

    Science.gov (United States)

    De Haro-Del Rio, D A; Al-Jubouri, S; Al-Joubori, S; Kontogiannis, O; Papadatos-Gigantes, D; Ajayi, O; Li, C; Holmes, S M

    2015-05-30

    In this paper, the sorptive kinetic and diffusional characteristics of caesium ion removal from aqueous solution by carbon-supported clinoptilolite composites are presented. Natural clinoptilolite was supported on carbonaceous scaffolds prepared from date stones. Thermal treatment was applied to produce voids in the carbon which was conditioned using polydiallyldimethylammonium chloride to facilitate the clinoptilolite attachment. This method allowed the formation of a consistent zeolite layer on the carbon surface. The composite was applied in the removal of non-radioactive caesium ions showing an enhanced uptake from 55 mg g(-1) to 120.9 mg g(-1) when compared to clinoptilolite. Kinetic studies using Pseudo First Order model revealed an enhanced rate constant for carbon-clinoptilolite (0.0252 min(-1)) in comparison with clinoptilolite (0.0189 min(-1)). The Pseudo-First Order model described the process for carbon-clinoptilolite, meanwhile Pseudo Second Order model adjusted better for pure clinoptilolite. Diffusivity results suggested that mass transfer resistances involved in the Cs(+) sorption are film and intraparticle diffusion for natural clinoptilolite and intraparticle diffusion as the mechanism that controls the process for carbon-clinoptilolite composite. The most significant aspect being that the vitrified volume waste can be reduced by over 60% for encapsulation of the same quantity of caesium due to the enhanced uptake of zeolite.

  10. Peculiarities of sorption isotherm and sorption chemisms of caesium by mixed nickel-potassium ferrocyanide based on hydrated titanium dioxide

    OpenAIRE

    Voronina, A. V.; Semenishchev, V. S.; Nogovitsyna, E. V.; Betenekov, N. D.

    2013-01-01

    Sorption isotherm of caesium from tap water by mixed nickel-potassium ferrocyanide based on hydrated titanium dioxide is obtained for a wide range of concentrations of caesium. It is shown that there are three types of specificity to caesium sorption sites in this sorbent. Sorption chemisms of caesium are studied, factors conditioned high sorption capacity of the sorbent are revealed. It is shown that occupation of sorption sites I and II is well approximated by Langmuir equilibrium and this ...

  11. Development of electrokinetic remediation for caesium: A feasibility study of 2D electrode configuration system

    Science.gov (United States)

    Syah Putra, Rudy

    2016-02-01

    Agar matrix was artificially contaminated with caesium and subjected to rapid assessment of electrokinetic treatment on the basis of the 2D electrode configuration. The effect of caesium concentration on the process was investigated using different electrode configuration (i.e. rectangular, hexagonal and triangular). During treatment the in situ pH distribution, the current flow, and the potential distribution were monitored. At the end of the treatment, the caesium concentration distribution was measured. The results of these experiments showed that for caesium contamination, pH control is essential in order to create a suitable environment throughout the agar matrix to enable contaminant removal. It was found that the type of electrode configuration used to control the pH affected the rate of caesium accumulation. All of the electrode configurations tested was effective, but the highest caesium extraction was achieved when the hexagonal pattern was used to control the pH. After 72 h of treatment at 50 mA, the concentration of caesium decreased gradually from the second and first layer of agar matrix throughout the cell, suggesting that most of the caesium was concentrated on the cathode part.

  12. Optimization of caesium dynamics in large and powerful RF sources for negative hydrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Mimo, Alessandro; Wimmer, Christian; Wuenderlich, Dirk; Fantz, Ursel [Max-Planck-Institut fuer Plasmaphysik, 85748 Garching (Germany)

    2015-05-01

    The development of large and powerful RF sources for negative hydrogen and deuterium ions is mandatory for the realization of the Neutral Beam Injection system at ITER. Caesium seeding into negative ion sources is necessary to obtain the required ion current with a tolerable level of co-extracted electrons. The caesium dynamics, during both plasma and vacuum phases, was investigated by means of the Monte Carlo transport code CsFlow3D, which is used to simulate the time evolution of the distribution of neutral and ionic caesium in the IPP prototype RF ion source. Simulations were performed for different durations of plasma-on and plasma-off phases, with the purpose of understanding how the duty cycle influences the caesium distribution and hence the source performance. In order to investigate asymmetry effects in the caesium distribution, caused by the positioning of caesium evaporator, the caesium coverage on the top and on the bottom part of the plasma grid was simulated and data were compared to the caesium density measured by laser absorption in the prototype source. The next step will be to introduce in the code the simulation of diagnostics such as laser absorption spectroscopy and optical emission spectroscopy, in order to achieve a direct benchmark of the code with experimental data.

  13. The removal of caesium ions using supported clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    De Haro-Del Rio, D.A.; Al-Joubori, S.; Kontogiannis, O.; Papadatos-Gigantes, D.; Ajayi, O.; Li, C.; Holmes, S.M., E-mail: stuart.holmes@manchester.ac.uk

    2015-05-30

    Highlights: • Natural clinoptilolite was supported over carbon structures produced from wastes. • Carbon–clinoptilolite showed an improved Cs{sup +} ions sorption capacity. • Overall kinetic rate was improved using carbon–clinoptilolite composite. • Diffusive resistances were modified using the composite and pure zeolite. • Final disposition volume can be reduced up to 60% by encapsulation. - Abstract: In this paper, the sorptive kinetic and diffusional characteristics of caesium ion removal from aqueous solution by carbon-supported clinoptilolite composites are presented. Natural clinoptilolite was supported on carbonaceous scaffolds prepared from date stones. Thermal treatment was applied to produce voids in the carbon which was conditioned using polydiallyldimethylammonium chloride to facilitate the clinoptilolite attachment. This method allowed the formation of a consistent zeolite layer on the carbon surface. The composite was applied in the removal of non-radioactive caesium ions showing an enhanced uptake from 55 mg g{sup −1} to 120.9 mg g{sup −1} when compared to clinoptilolite. Kinetic studies using Pseudo First Order model revealed an enhanced rate constant for carbon–clinoptilolite (0.0252 min{sup −1}) in comparison with clinoptilolite (0.0189 min{sup −1}). The Pseudo-First Order model described the process for carbon–clinoptilolite, meanwhile Pseudo Second Order model adjusted better for pure clinoptilolite. Diffusivity results suggested that mass transfer resistances involved in the Cs{sup +} sorption are film and intraparticle diffusion for natural clinoptilolite and intraparticle diffusion as the mechanism that controls the process for carbon–clinoptilolite composite. The most significant aspect being that the vitrified volume waste can be reduced by over 60% for encapsulation of the same quantity of caesium due to the enhanced uptake of zeolite.

  14. High Performance Small Optically Pumped Caesium Beam Frequency Standard

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-Wei; YANG Dong-Hai

    2007-01-01

    An experiment of a high performance small optically pumped caesium (Cs) beam frequency standard is reported. An extended cavity diode laser works as the probing laser, of which the frequency is stabilized by the Zeeman modulation method. The running parameters of the frequency standard are dynamically optimized via digital servo electronics. The experimental setup improves the frequency stability up to 1.8 × 10-12 atτ= 1 s and about 1.0 × 10~13 at τ= 105 s (Allan deviation).

  15. Assessment of the caesium-137 flux adsorbed to suspended sediment in a reservoir in the contaminated Fukushima region in Japan.

    Science.gov (United States)

    Mouri, Goro; Golosov, Valentin; Shiiba, Michiharu; Hori, Tomoharu

    2014-04-01

    We estimated the flux of caesium-137 adsorbed to suspended sediment in the Kusaki Dam reservoir in the Fukushima region of eastern Japan, which was contaminated by the Fukushima Nuclear Power Plant accident. The amount and rate of reservoir sedimentation and the caesium-137 concentration were validated based on the mixed-particle distribution and a sediment transport equation. The caesium-137 and sediment flux data suggested that wash load, suspended load sediment, and caesium-137 were deposited and the discharge and transport processes generated acute pollution, especially during extreme rainfall-runoff events. Additionally, we qualitatively assessed future changes in caesium-137 and sediment fluxes in the reservoir. The higher deposition and discharge at the start of the projection compared to the 2090s are most likely explained by the radioactive decay of caesium-137 and the effects of reservoir sedimentation. Predictions of the impacts of future climate on sediment and caesium-137 fluxes are crucial for environmental planning and management.

  16. Caesium 137 in northern Swedish moose: The first year after the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Danell, K.; Nelin, P. (Swedish Univ. of Agricultural Science, Umeaa (Sweden). Dept. of Wildlife Ecology); Wickman, G. (Umeaa Univ. (Sweden). Radiation Physics Dept.)

    1989-01-01

    Levels of /sup 137/ caesium were monitored in northern Sweden during the first year after the Chernobyl accident (April 1986). Samples were collected from 3661 moose in an area where the deposited /sup 137/ caesium ranged from two to 60 kilo-becquerel per m/sup 2/. Concentrations of caesium in moose muscle correlated positively with the ground deposition of caesium. On average, the caesium levels found in moose after Chernobyl were about 470 Bq per kg fresh mass for calves and close to 300 for older animals. The average level in moose before the accident was 33 Bq per kg. Among moose older than one year, higher concentrations were found in females than in the males. There was a pronounced seasonal variation in the /sup 137/ caesium concentration found in moose. Within the investigation area the presence of caesium in moose resulted in a minor proportion of the hunters discarding the animals shot and/or terminating the hunt before the end of the season.

  17. Bichromatic State-insensitive Trapping of Caesium Atoms

    CERN Document Server

    Metbulut, M M

    2015-01-01

    State-insensitive dipole trapping of multilevel atoms can be achieved by an appropriate choice of the wavelength of the trapping laser, so that the interaction with the different transitions results in equal AC Stark shifts for the ground and excited states of interest. However this approach is severely limited by the availability of coherent sources at the required wavelength and of appropriate power. This work investigates state-insensitive trapping of caesium atoms for which the required wavelength of 935.6 nm is inconvenient in terms of experimental realization. Bichromatic state-insensitive trapping is proposed to overcome the lack of suitable laser sources. We first consider pairs of laser wavelengths in the ratio 1:2 and 1:3, as obtained via second- and third- harmonic generation. We found that the wavelength combinations 931.8-1863.6 nm and 927.5-2782.5 nm are suitable for state-insensitive trapping of caesium atoms. In addition, we examine bichromatic state-insensitive trapping produced by pairs of l...

  18. Bichromatic state-insensitive trapping of caesium atoms

    Science.gov (United States)

    Metbulut, M. M.; Renzoni, F.

    2015-12-01

    State-insensitive dipole trapping of multilevel atoms can be achieved by an appropriate choice of the wavelength of the trapping laser, so that the interaction with the different transitions results in equal AC Stark shifts for the ground and excited states of interest. However, this approach is severely limited by the availability of coherent sources at the required wavelength and of appropriate power. This work investigates state-insensitive trapping of caesium atoms for which the required wavelength of 935.6 nm is inconvenient in terms of experimental realization. Bichromatic state-insensitive trapping is proposed to overcome the lack of suitable laser sources. We first consider pairs of laser wavelengths in the ratio 1:2 and 1:3, as obtained via second- and third-harmonic generation. We found that the wavelength combinations 931.8-1863.6 nm and 927.5-2782.5 nm are suitable for state-insensitive trapping of caesium atoms. In addition, we examine bichromatic state-insensitive trapping produced by pairs of laser wavelengths corresponding to currently available high-power lasers. These wavelength pairs were found to be in the range of 585-588 nm and 623-629 for one laser and 1064-1080 nm for the other.

  19. Crustaceous lichens sensitive monitor of caesium-137 radiation level in terrestrial environment

    Institute of Scientific and Technical Information of China (English)

    Du Chunguang; Zhao Ye; Zhang Jing; Xu Cuihua

    2005-01-01

    The activity of caesium-137 (Bq/kg) in the crustaceous lichens and other samples was determined to prove the feasibility that crustaceous lichens work as a sensitive biology monitor to record the caesium-137 (Bq/kg) radiation levels of terrestrial environment. The measurements were performed with GEM series HPGe (high-purity Germanium) coaxial detector system (ADCAM -100) made by EC & GORTEC Company in USA. It was found that the activity of caesium-137 (Bq/kg) in the crustaceous lichens was one order of magnitude higher than that found in surface soil,and was over three orders of magnitude higher than those found in the familiar biological samples. These results proved that crustaceous lichens may be one of the most sensitive biological monitors about the remote transmission and environmental radiation levels of caesium-137.

  20. Improvements and New Evaluation of NIM4 Caesium Fountain Clock at NIM in 2005-2006

    Institute of Scientific and Technical Information of China (English)

    LI Tian-Chu; LI Ming-Shou; LIN Ping-Wei; WANG Ping; CHEN Wei-Liang; LIU Nian-Feng; LIN Yi-Ge

    2007-01-01

    The NIM4 caesium fountain clock has been operating stably and sub-continually since August 2003. We present our improvements on NIM4 in 2005-06 and the most recent evaluation for its frequency shifts with an uncertainty of 5×10-15. A 203-day comparison between NIM4 and GPS time shows an agreement of 2×10-14. Finally the construction of the NIM5 transportable caesium fountain clock is briefly reported.

  1. Highly NO2 sensitive caesium doped graphene oxide conductometric sensors

    Directory of Open Access Journals (Sweden)

    Carlo Piloto

    2014-07-01

    Full Text Available Here we report on the synthesis of caesium doped graphene oxide (GO-Cs and its application to the development of a novel NO2 gas sensor. The GO, synthesized by oxidation of graphite through chemical treatment, was doped with Cs by thermal solid-state reaction. The samples, dispersed in DI water by sonication, have been drop-casted on standard interdigitated Pt electrodes. The response of both pristine and Cs doped GO to NO2 at room temperature is studied by varying the gas concentration. The developed GO-Cs sensor shows a higher response to NO2 than the pristine GO based sensor due to the oxygen functional groups. The detection limit measured with GO-Cs sensor is ≈90 ppb.

  2. Poly[μ5-{hydrogen bis[(E-cinnamato]}-caesium

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2014-02-01

    Full Text Available In the structure of the title polymeric complex, [Cs(C9H7O2(C9H8O2]n, a caesium salt of trans-cinnamic acid, the Cs+ ions of the two individual irregular CsO8 coordination polyhedra lie on twofold rotation axes and are linked by four bridging carboxyl O-atom donors from two cinnamate ligand species. These two ligand components are interlinked through a delocalized H atom within a short O...H...O hydrogen bond. Structure extension gives a two-dimensional coordination polymer which lies parallel to (001. The structure was determined from a crystal twinned by non-merohedry, with a twin component ratio of approximately 1:1.

  3. Observation of EIA in closed and open caesium atomic system

    Institute of Scientific and Technical Information of China (English)

    Zhao Jian-Ming; Zhao Yan-Ting; Huang Tao; Xiao Lian-Tuan; Jia Suo-Tang

    2005-01-01

    We present an experimental study on electromagnetically induced absorption (EIA) in the closed transition of a degenerate two-level Cs atomic system. The coupling and probe lasers coupled with the transition 6S1/2F=4 →6P3/2F'=5 of caesium atom. The signal of EIA was obtained and the frequency detuning and intensity effect of the pumping laser were experimentally investigated. The EIA signal in 6S1/2 F=4 → 6P3/2 F'=4 and 6S1/2 F=4 → 6P3/2F'=3 open transitions was also obtained. As the repumping laser couples with the transition of 6S1/2 F=3 → 6P3/2F'=4, the EIA signal is increased due to the hyperfine optical pumping.

  4. Caesium extraction by calixarene molecules: Some aspects of extraction kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Simon, N.; Tournois, B.; Volle, G

    2004-07-01

    In the framework of the environment Code (2000 studies were developed to recover long-lived fission products (F.P.) from acidic highly radioactive effluents issuing the reprocessing of spent fuels, to destroy them by transmutation or to encapsulate them into specific matrices. Efforts had been directed towards caesium, particularly {sup 135}Cs, which is one of the most harmful fission products because of its long half life (more than 2.10{sup 6} years) and its mobility in repository. The flow-sheet will be included in the general scheme of long-lived radionuclide partitioning. It was decided to define a process based on liquid-liquid extraction. Crown-calixarenes molecules were chosen for process development. To refine the flowsheet diagram, it is necessary to know the rate constants of the implied chemical reactions involved in the extraction. This paper describes the first determination of rate constant in the Cs extraction with crown calixarenes. (authors)

  5. Zeolite and bentonite as caesium binders in reindeer feed

    Directory of Open Access Journals (Sweden)

    Birgitta Åhman

    1990-09-01

    Full Text Available The effects of zeolite and bentonite on the accumulation and excretion of radiocaesium (Cs-137 in reindeer were studied in two feeding experiments. Six animals in each experiment were given lichens contaminated with radiocaesium from fallout after the Chernobyl nuclear power plant accident. In addition, they were fed pellets containing bentonite (Experiment I or zeolite (Experiment II. Two animals, controls, in each experiment received no caesium-binder. The activity concentration of radiocaesium in blood was used to evalute the radiocaesium level in the body. Faeces and urine were collected to measue the excration of radiocaesium. The animals in Experiment I were depleted of radiocaesium before the start of the experiment. After three weeks, with an intake of 17 - 18 kBq Cs-137/day, the controls had reached activity concentrations of radiocaesium in blood corresponding to 4 - 4.5 kBq Cs-137/kg in muscle. Reindeer fed 23 or 46 g of bentonite per day stabilized at values below 0.8 kfiq/kg in muscle. In Experiment II, the reindeer started with radiocaesium activity concentrations in blood corresponding to 2 - 4.5 kBq Cs-137/kg in muscle. After four weeks of feeding, with an intake at about 8.5 kBq Cs-137/day, controls had increased their radiocaesium values by an average of 40%. Reindeer receiving 25 or 50 g zeolite per day decreased with 18 and 45%, respectively. Net absorption of radiocaesium from the gastro-intestinal tract was calculated at 50 -70% in animals receiving no caesium-binder. Reindeer fed bentonite had an absorption below 10% while those fed zeolite absorbed around 35%.

  6. Influence of arbuscular mycorrhizal fungi and the expression of K+/Cs+ transporters on the accumulation of caesium by plants

    OpenAIRE

    Wiesel, Lea

    2011-01-01

    Radiocaesium (134Cs, 137Cs) is of environmental concern because of its incorporation into the food chain and prolonged emission of harmful radiation. Plants take up caesium via cation transporters which cannot discriminate between radioactive and stable caesium (133Cs). Around 80% of angiosperms live in symbiosis with arbuscular mycorrhizal (AM) fungi that deliver mineral nutrients to their hosts. Contrasting effects of AM fungi on caesium accumulation by plants have been reported. The ultima...

  7. A collisional radiative model for caesium and its application to an RF source for negative hydrogen ions

    Science.gov (United States)

    Wünderlich, D.; Wimmer, C.; Friedl, R.

    2015-04-01

    A collisional radiative (CR) model for caesium atoms in low-temperature, low-pressure hydrogen-caesium plasmas is introduced. This model includes the caesium ground state, 14 excited states, the singly charged caesium ion and the negative hydrogen ion. The reaction probabilities needed as input are based on data from the literature, using some scaling and extrapolations. Additionally, new cross sections for electron collision ionization and three-body recombination have been calculated. The relevance of mutual neutralization of positive caesium ions and negative hydrogen ions is highlighted: depending on the densities of the involved particle species, this excitation channel can have a significant influence on the population densities of excited states in the caesium atom. This strong influence is successfully verified by optical emission spectroscopy measurements performed at the IPP prototype negative hydrogen ion source for ITER NBI. As a consequence, population models for caesium in electronegative low-temperature, low-pressure hydrogen-caesium plasmas need to take into account the mutual neutralization process. The present CR model is an example for such models and represents an important prerequisite for deducing the total caesium density in surface production based negative hydrogen ion sources.

  8. Development of prediction models for radioactive caesium distribution within the 80-km radius of the Fukushima Daiichi nuclear power plant.

    Science.gov (United States)

    Kinase, Sakae; Takahashi, Tomoyuki; Sato, Satoshi; Sakamoto, Ryuichi; Saito, Kimiaki

    2014-08-01

    Preliminary prediction models have been studied for the radioactive caesium distribution within the 80-km radius of the Fukushima Daiichi nuclear power plant. The models were represented by exponential functions using ecological half-life of radioactive caesium in the environment. The ecological half-lives were derived from the changes in ambient dose equivalent rates through vehicle-borne surveys. It was found that the ecological half-lives of radioactive caesium were not constant within the 80-km radius of the Fukushima Daiichi nuclear power plant. The ecological half-life of radioactive caesium in forest areas was found to be much larger than that in urban and water areas.

  9. A collisional radiative model for caesium and its application to an RF source for negative hydrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Wünderlich, D., E-mail: dirk.wuenderlich@ipp.mpg.de; Wimmer, C. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Friedl, R. [AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany)

    2015-04-08

    A collisional radiative (CR) model for caesium atoms in low-temperature, low-pressure hydrogen-caesium plasmas is introduced. This model includes the caesium ground state, 14 excited states, the singly charged caesium ion and the negative hydrogen ion. The reaction probabilities needed as input are based on data from the literature, using some scaling and extrapolations. Additionally, new cross sections for electron collision ionization and three-body recombination have been calculated. The relevance of mutual neutralization of positive caesium ions and negative hydrogen ions is highlighted: depending on the densities of the involved particle species, this excitation channel can have a significant influence on the population densities of excited states in the caesium atom. This strong influence is successfully verified by optical emission spectroscopy measurements performed at the IPP prototype negative hydrogen ion source for ITER NBI. As a consequence, population models for caesium in electronegative low-temperature, low-pressure hydrogen-caesium plasmas need to take into account the mutual neutralization process. The present CR model is an example for such models and represents an important prerequisite for deducing the total caesium density in surface production based negative hydrogen ion sources.

  10. DECOMMISSIONING OF A CAESIUM-137 SEALED SOURCE PRODUCTION FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Murray, A.; Abbott, H.

    2003-02-27

    Amersham owns a former Caesium-137 sealed source production facility. They commissioned RWE NUKEM to carry out an Option Study to determine a strategy for the management of this facility and then the subsequent decommissioning of it. The decommissioning was carried out in two sequential phases. Firstly robotic decommissioning followed by a phase of manual decommissioning. This paper describes the remote equipment designed built and operated, the robotic and manual decommissioning operations performed, the Safety Management arrangements and summarizes the lessons learned. Using the equipment described the facility was dismantled and decontaminated robotically. Some 2300kg of Intermediate Level Waste containing in the order of 4000Ci were removed robotically from the facility. Ambient dose rates were reduced from 100's of R per hour {gamma} to 100's of mR per hour {gamma}. The Telerobotic System was then removed to allow man access to complete the decommissioning. Manual decommissioning reduced ambient dose rates further to less than 1mR per hour {gamma} and loose contamination levels to less than 0.25Bq/cm2. This allowed access to the facility without respiratory protection.

  11. Uptake and retention of radio-caesium in earthworms cultured in soil contaminated by the Fukushima nuclear power plant accident.

    Science.gov (United States)

    Fujiwara, K; Takahashi, T; Nguyen, P; Kubota, Y; Gamou, S; Sakurai, S; Takahashi, S

    2015-01-01

    To understand the effects of radionuclides on non-human biota and the environment, it is essential to study the intake and metabolism of radio-isotopes in earthworms which are among the most important soil organisms, and Eisenia fetida, which were used in this study, are known to be sufficiently sensitive to chemicals and representative of common earthworms. In this study, we assessed the concentration ratios, uptake and retention, absorbed dose rate, and distribution of radio-caesium in earthworms. The concentration ratios of (137)Cs (i.e., the concentrations of radio-caesium in earthworms relative to those in dry soil) were higher early in the culturing period and decreased gradually over the experimental period. (137)Cs taken up by E. fetida was cleared rapidly after the worms were cultured in radio-caesium-free soil, suggesting that the metabolism of radio-caesium in earthworms is very rapid. Autoradiography demonstrated that the concentration of radio-caesium within the digestive tract was as high as that in the soil, while radio-caesium in the body tissue was lower than radio-caesium in the soil and was almost uniformly distributed among earthworm tissues. The highest absorbed dose rate of total exposure to radio-caesium ((137)Cs + (134)Cs) was calculated to be 1.9 × 10(3) (μGy/day) in the earthworms.

  12. Autler-Townes doublet in novel sub-Doppler spectra with caesium vapour cell

    Institute of Scientific and Technical Information of China (English)

    Wang Yan-Hua; Yang Jai-Jing; Du Zhi-Jing; Zhang Tian-Cai; Wang Jun-Min

    2006-01-01

    With a coupling laser locked to caesium 6S1/2 Fg=4-6P3/2Fe=5 cycling transition and a co-propagating probe laser scanned across 6S1/2Fg=4-6P3/2Fe=3, 4 and 5 transitions, a novel scheme for sub-Doppler spectra in Doppler-broadened V-type three-level system is demonstrated by detecting the transmission of the coupling laser through a caesium vapour cell. The Autler-Townes doublet in the sub-Doppler spectra of the coupling laser is clearly observed. The effects of coupling laser intensity on the splitting and linewidth of the Autleraking the multiple hyperfine levels of caesium atom into account, a brief analysis is presented.

  13. Continuously transferring cold atoms in caesium double magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Yan Shu-Bin; Geng Tao; Zhang Tian-Cai; Wang Jun-Min

    2006-01-01

    We have established a caesium double magneto-optical trap (MOT) system for cavity-QED experiment, and demonstrated the continuous transfer of cold caesium atoms from the vapour-cell MOT with a pressure of ~ 1 × 10-6 Pa to the ultra-high-vacuum (UHV) MOT with a pressure of ~ 8 × 10-8 Pa via a focused continuous-wave transfer laser beam. The effect of frequency detuning as well as the intensity of the transfer beam is systematically investigated, which makes the transverse cooling adequate before the atoms leak out of the vapour-cell MOT to reduce divergence of the cold atomic beam. The typical cold atomic flux got from vapour-cell MOT is ~ 2 × 107 atoms/s. About 5 × 106 caesium atoms are recaptured in the UHV MOT.

  14. Caesium europium(III) polyphosphate, CsEu(PO3)4

    OpenAIRE

    Jing Zhu; Wen-Dan Cheng; Hao Zhang

    2009-01-01

    Caesium europium polyphosphate, CsEu(PO3)4, was synthesized by a high-temperature solution reaction. Its structure is charaterized by a three-dimensional framework made up of double PO4 spiral chains and EuO8 and CsO11 polyhedra.

  15. Extraction of caesium from mosses and incorporation into an oxalate crystalline lattice.

    Science.gov (United States)

    Nedić, Olgica; Dragović, Snezana

    2006-01-01

    The ratios of stable and radioactive isotopes in the environment are not constant and their effects on living organisms are not the same. Whilst radionuclides can be monitored by measuring their radioactivity levels, it is also important to determine the stable isotopes. The method described in this paper represents a simple and cheap process by which to extract caesium from moss, without significant destruction of the plant, and to incorporate the isolated caesium into a water-soluble crystal. Ammonium oxalate and phosphoric acid are water-soluble substances at 5% concentration but, when the solutions are combined, crystallisation occurs. Crystals were estimated to contain 68.30% O, 20.98% C, 4.68% H, 6.04% N and less than 0.01% P, corresponding to NH4HC2O4 x H2C2O4 x 2H2O (C4H11NO10). The crystal mass did not vary with the species of moss, although the effectiveness of caesium extraction did. Typically, 73.0 +/- 6.1% of the solubilised caesium was entrapped within the crystals.

  16. The use of bentonite and zeolite as caesium-binders in feed to reindeer - experiences from Sweden

    Directory of Open Access Journals (Sweden)

    Birgitta Åhman

    1990-09-01

    Full Text Available Feeding is used in Sweden to lower radiocaesium levels in reindeer before slaughter. In feeds used for this purpose, bentonite is added as a caesium-binder to prevent absorption of radiocaesium, since the animals usually have som access to contaminated pasture in their corrals. Bentonite is efficient as a caesium-binder but increases water consumption and excretion of urine. Zeolite has been used as a caesium-binder to reindeer in a few experiments. The effect, however, has been inferior to that of bentonite. It seems that zeolite, mixed in feeds, loose some of its effect as the feed is stored. The need of a caesium-binder is demonstrated by results from practical feeding of reindeer where radiocaesium levels have not decreased as expected when feed without bentonite has been used.

  17. Availability of caesium radionuclides to plants - classification of soils and role of mycorrhiza

    Energy Technology Data Exchange (ETDEWEB)

    Drissner, J.; Buermann, W.; Enslin, F.; Heider, R.; Klemt, E.; Miller, R.; Schick, G.; Zibold, G. [Fachhochschule Ravensburg-Weingarten, D-88241 Weingarten (Germany)

    1998-10-01

    At different locations in spruce stands spread rather homogeneously over southern Baden-Wuerttemberg, samples of soil and plants were taken and the vertical distribution of the caesium radionuclides in the soil was studied. As a direct measure of the bioavailability, the aggregated transfer factor, T{sub ag}, was determined for fern, bilberry, raspberry, blackberry, and clover. The T{sub ag} (in m2 kg{sup -1}) is defined by the specific caesium activity (in Bq kg{sup -1}) of the dry mass of the plants, divided by the total inventory (in Bq m{sup -2}) of the soil. It varies between 0{center_dot}5 and 0{center_dot}001 m2kg{sup -1}, being highest for fern and lowest for blackberry or clover at all sampling sites. Most decisive for the value of the T{sub ag} are kind of humus deposit, thickness and pH value of the humus layers. Also important are the soil properties, whereas geology has only a minor influence on T{sub ag}. At different sampling sites in spruce forests, the T{sub ag} can vary by two orders of magnitude for one plant species. Caesium desorption experiments were performed. We could not find a dependence of the transfer of caesium to the plant on the desorbability of caesium from the soil, which implies a more complex transport mechanism than simple ion exchange in the soil solution. It is suggested that the transport of caesium is mediated by mycorrhiza fungi. Therefore, we studied the density of mycorrhiza hyphae in the O{sub f}, O{sub h} and A{sub h} soil horizons of two sites differing in T{sub ag} by a factor of 10. The densities of mycorrhiza hyphae in the O{sub h} and A{sub h} soil horizons each differ by a factor of 2 for the two sites. Yet, the effect of the hyphae density on radiocaesium uptake has to be a subject of further investigation. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. Pressure and temperature dependence of the chlorine NQR in caesium and sodium chlorates.

    Science.gov (United States)

    Ramesh, K P; Suresh, K S; Raghavendra Rao, C; Ramakrishna, J

    2008-06-01

    The (35)Cl nuclear quadrupole resonance (NQR) frequencies (nu(Q)) in caesium and sodium chlorates were measured as a function of temperature, from 77 to 300 K at different pressures up to 5.1 kbar, and the data were analysed to estimate the volume dependence of the electric field gradient (EFG), torsional frequency and also the contributions to the NQR frequency from static and dynamic effects. The variation of spin-lattice relaxation time with pressure at different temperatures was studied in the case of sodium chlorate and at room temperature in case of caesium chlorate. The pressure dependence of the spin-lattice relaxation time (T(1)) suggests that the relaxation is mainly due to the torsional motions.

  19. Joint monitoring of hydrosedimentological events and transport of caesium 137 in a small basin

    Energy Technology Data Exchange (ETDEWEB)

    Preti, F.; Lubello, C.; Becchi, I. (Florence Univ. (Italy). Dept. of Civil Engineering)

    1993-01-01

    Research was carried out to analyse the transport of Caesium 137 in a small calcareous watershed (3.6 Km[sup 2]) of the Tuscan Appennines (Central Italy). The presence of the radionuclide 137 Cs, adsorbed by the soil, is due to the nuclear tests in the 1960s-70s and to the Chernobyl disaster in 1986. For representation of the transport dynamics of 137 Cs a distributed parameters model has been developed, in order to consider the variability of the physical characteristics of the area. The results of the simulation, compared with the concentrations of Caesium measured by a devised experimental method in the lake-sediments of a hill catchment placed in the closing section of the basin, showed an excellent agreement. (author).

  20. Dependence of microwave-excitation signal parameters on frequency stability of caesium atomic clock

    Science.gov (United States)

    Petrov, A. A.; Davydov, V. V.; Vologdin, V. A.; Zalyotov, D. V.

    2015-11-01

    New scheme of the microwave - excitation signal for the caesium atomic clock is based on method of direct digital synthesis. The theoretical calculations and experimental research showed decrease step frequency tuning by several orders and improvement the spectral characteristics of the output signal of frequency synthesizer. A range of generated output frequencies is expanded, and the possibility of detuning the frequency of the neighboring resonance of spectral line that makes it possible to adjust the C-field in quantum frequency standard is implemented. Experimental research of the metrological characteristics of the quantum frequency standard on the atoms of caesium - 133 with new design scheme of the microwave - excitation signal showed improvement in daily frequency stability on 1.2*10-14.

  1. Inferring ecological separation from regional differences in radioactive caesium in harbour porpoises Phocoena phocoena

    OpenAIRE

    Tolley, Krystal A; Heldal, Hilde Elise

    2002-01-01

    Geographic variation in the level of radioactive caesium-137 (Cs-137) was examined from the axial muscle of 36 harbour porpoises Phocoena phocoena obtained as bycatch from 5 locations along the coast of Norway, ranging from southern (North Sea) to northern (Barents Sea) Norway. Levels of Cs-137 in seawater and sediments have been found to differ along the coast of Norway due to distance from point sources, such as the Sellafield nuclear fuel reprocessing plant in Cumbria, UK (discharging into...

  2. Body concentration of caesium-137 in patients from Western Isles of Scotland.

    OpenAIRE

    Isles, C G; Robertson, I.; MacLeod, J A; Preston, T; East, B W; Hole, D J; Lever, A. F.

    1991-01-01

    OBJECTIVES--To compare caesium-137 concentrations in patients from the Western Isles Health Board, Glasgow area, and other parts of the Scottish mainland, and to investigate the source of 137Cs in patients from the Western Isles. DESIGN--Study of hypertensive patients having electrolyte concentrations measured, including 137Cs. Interview by questionnaire of island subjects about intake of foods likely to contain radiocaesium and the source of these foods. Measurement of 137Cs and 134Cs in foo...

  3. The spatial distribution of caesium-137 over Northern Ireland from fallout from the Chernobyl nuclear accident

    OpenAIRE

    Rawlins, B. G.; Scheib, C.; Tyler, A.N.; Jones, D.; Webster, R; Young, M. E.

    2009-01-01

    The spatial distribution of caesium-137 (137Cs) across the land is of much interest because it can tell us about the redistribution of the radionuclide as a result of soil erosion, differential migration through the soil—or its complement, differential retention in the soil. Any such inferences from survey measurements depend on the assumption of a broadly even distribution from weapons testing fallout, and the substantial deposition of 137Cs in rain following the Chernobyl accide...

  4. Caesium 137 in meat from reindeer and grouses from Svaldbard 1980

    Energy Technology Data Exchange (ETDEWEB)

    Kjos-Hanssen, B.; Rennesund, J.S. (Forsvarets Forskningsinstitutt, Kjeller (Norway))

    1981-01-01

    Concentration of Caesium 137 in meat from Spitsbergen (Svalbard) and mainland Norway reindeer has been measured. It appears that the concentration values for Spitsbergen are of the order of 1 per cent of corresponding values for the mainland. It is suggested that low precipitation rates and a different reindeer diet contributes to the low Cs 137 concentration values in Svaldbard. The concentration of Cs 137 in Svaldbard grouse did not exceed the detection limit of the measurements (approximately 10 pCi/kg).

  5. (Caesium 137 in meat from reindeer and grouse from Svalbard 1980 (author's transl))

    Energy Technology Data Exchange (ETDEWEB)

    Kjos-Hanssen, B.; Rennesund, J.S.

    Concentration of Caesium 137 in meat from Spitsbergen (Svalbard) and mainland Norway reindeer has been measured. It appears that the concentration values for Spitsbergen are of the order of 1 per cent of corresponding values for the mainland. It is suggested that low precipitation rates and a different reindeer diet contributes to the low Cs 137 concentration values in Svalbard. The concentration of Cs 137 in Svalbard grouse did not exceed the detection limit of the measurements (infinity 10 pCi/kg).

  6. The electron electric dipole moment enhancement factors of Rubidium and Caesium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Nataraj, H S [Indian Institute of Astrophysics, Bangalore 560 034 (India); Sahoo, B K [Max Planck Institute for the Physics of Complex Systems, 01187 Dresden (Germany); Das, B P [Indian Institute of Astrophysics, Bangalore 560 034 (India); Chaudhuri, R K [Indian Institute of Astrophysics, Bangalore 560 034 (India); Mukherjee, D [Indian Association for the Cultivation of Sciences, Calcutta 700 032 (India)

    2007-09-15

    The enhancement factors of the electric dipole moment (EDM) of the ground states of two paramagnetic atoms; rubidium (Rb) and caesium (Cs) which are sensitive to the electron EDM are computed using the relativistic coupled-cluster theory and our results are compared with the available calculations and measurements. The possibility of improving the limit for the electron EDM using the results of our present work is pointed out.

  7. The electron electric dipole moment enhancement factors of Rubidium and Caesium atoms

    CERN Document Server

    Nataraj, H S; Das, B P; Chaudhuri, R K; Mukherjee, D

    2007-01-01

    The enhancement factors of the electric dipole moment (EDM) of the ground states of two paramagnetic atoms; rubidium (Rb) and caesium (Cs) which are sensitive to the electron EDM are computed using the relativistic coupled-cluster theory and our results are compared with the available calculations and measurements. The possibility of improving the limit for the electron EDM using the results of our present work is pointed out.

  8. Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments

    Science.gov (United States)

    Dzene, Liva; Ferrage, Eric; Viennet, Jean-Christophe; Tertre, Emmanuel; Hubert, Fabien

    2017-01-01

    Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs+ and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs+ mobility in soils remain poorly understood due to the mixture of these minerals with other clays and organic matter. We performed acidic weathering of a vermiculite to mimic the aluminization process in soils. Combination of structure analysis and Cs+ extractability measurements show that the increase of aluminization is accompanied by an increase in Cs+ mobility. Crystal structure model for aluminized vermiculite is based on the interstratification of unaltered vermiculite layers and aluminized layers within the same particle. Cs+ in vermiculite layers is poorly mobile, while the extractability of Cs+ is greatly enhanced in aluminized layers. The overall reactivity of the weathered clay (cation exchange capacity, Cs+ mobility) is then governed by the relative abundance of the two types of layers. The proposed layer model for aluminized vermiculite with two coexisting populations of caesium is of prime importance for predicting the fate of caesium in contaminated soil environments. PMID:28233805

  9. Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments

    Science.gov (United States)

    Dzene, Liva; Ferrage, Eric; Viennet, Jean-Christophe; Tertre, Emmanuel; Hubert, Fabien

    2017-02-01

    Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs+ and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs+ mobility in soils remain poorly understood due to the mixture of these minerals with other clays and organic matter. We performed acidic weathering of a vermiculite to mimic the aluminization process in soils. Combination of structure analysis and Cs+ extractability measurements show that the increase of aluminization is accompanied by an increase in Cs+ mobility. Crystal structure model for aluminized vermiculite is based on the interstratification of unaltered vermiculite layers and aluminized layers within the same particle. Cs+ in vermiculite layers is poorly mobile, while the extractability of Cs+ is greatly enhanced in aluminized layers. The overall reactivity of the weathered clay (cation exchange capacity, Cs+ mobility) is then governed by the relative abundance of the two types of layers. The proposed layer model for aluminized vermiculite with two coexisting populations of caesium is of prime importance for predicting the fate of caesium in contaminated soil environments.

  10. Investigations on caesium-free alternatives for H- formation at ion source relevant parameters

    Science.gov (United States)

    Kurutz, U.; Fantz, U.

    2015-04-01

    Negative hydrogen ions are efficiently produced in ion sources by the application of caesium. Due to a thereby induced lowering of the work function of a converter surface a direct conversion of impinging hydrogen atoms and positive ions into negative ions is maintained. However, due to the complex caesium chemistry and dynamics a long-term behaviour is inherent for the application of caesium that affects the stability and reliability of negative ion sources. To overcome these drawbacks caesium-free alternatives for efficient negative ion formation are investigated at the flexible laboratory setup HOMER (HOMogenous Electron cyclotron Resonance plasma). By the usage of a meshed grid the tandem principle is applied allowing for investigations on material induced negative ion formation under plasma parameters relevant for ion source operation. The effect of different sample materials on the ratio of the negative ion density to the electron density nH- /ne is compared to the effect of a stainless steel reference sample and investigated by means of laser photodetachment in a pressure range from 0.3 to 3 Pa. For the stainless steel sample no surface induced effect on the negative ion density is present and the measured negative ion densities are resulting from pure volume formation and destruction processes. In a first step the dependency of nH- /ne on the sample distance has been investigated for a caesiated stainless steel sample. At a distance of 0.5 cm at 0.3 Pa the density ratio is 3 times enhanced compared to the reference sample confirming the surface production of negative ions. In contrast for the caesium-free material samples, tantalum and tungsten, the same dependency on pressure and distance nH- /ne like for the stainless steel reference sample were obtained within the error margins: A density ratio of around 14.5% is measured at 4.5 cm sample distance and 0.3 Pa, linearly decreasing with decreasing distance to 7% at 1.5 cm. Thus, tantalum and tungsten do not

  11. Experimental study on the possibilities of direct transfer of caesium 137 from sediment to the carps (Cyprinus carpio L. )

    Energy Technology Data Exchange (ETDEWEB)

    Lambrechts, A.; Foulquier, L.

    1983-06-01

    The exchanges of caesium 137 with the Rhone river water and deposits and its direct transfer from water and deposits to the carp are studied. The sediments have a high retention capacity for radiocaesium associated with fine particles and certain clays (illite). Caesium desorption from sediment to water is always very weak (less than 5% of the initial activity of the sediments; it varies with the agitation and salinity of the water. The transfer of caesium from the water to the carps is characterized by a regular increase of activity in the fish. After 63 days of experimentation, equilibrium has not been reached, the carp have retained only 1% of the water activity, and their concentration factor is about 4. The transfer of caesium from sediment to the fish is weak but regular. After 79 days of experimentation, equilibrium has not been reached. Less than 1% of the sediments activity is found in the fish; the transfer factor is about 10/sup -3/. Because of the high content of caesium 137 in sediments, the activity of the carp is increased and the concentration factor, calculated in relation to the surface water, is greater than 60.

  12. Decreasing of transfer of caesium and strontium radionuclides from soil to vegetation - Use of modified aluminosilicates for decreasing of transfer of caesium and strontium radionuclides from soil to vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Voronina, Anna V.; Blinova, Marina O.; Semenischev, Vladimir S.; Kutergin, Andrey S. [Ural federal university, 620002 Ekaterinburg (Russian Federation)

    2014-07-01

    The method of addition of sorbents to soils is seemed to be the most efficient for decreasing of transfer of radionuclides from soil to vegetation. Using sorbents should possess affinity to natural systems, high specificity and selectivity and also irreversibility of sorption of radionuclides for effective retention of radionuclides as well as to prevent their migration into vegetation and further movement through food chains. Specificity, selectivity and reversibility of sorption of caesium and strontium radionuclides by natural aluminosilicates (glauconite, clinoptilolite) and modified ferrocyanide sorbents based on them was studied in this work. It was shown that the natural glauconite sorbs caesium from tap water with distribution coefficient K{sub d} = 10{sup (3.5±0.1)} mL/g, static exchange capacity of Cs is 11.0 mg/g; it shows lower specificity to strontium: K{sub d} = 10(2.5±0.1) mL/g, static exchange capacity = 9 mg/g. For clinoptilolite these parameters are for caesium K{sub d} = 10(4.4±0.5) mL/g, static exchange capacity 210 mg/g; for strontium K{sub d} = 10(3.5±0.1) mL/g, capacity = 12 mg/g. Ferrocyanide sorbents concentrate caesium radionuclides more effectively: distribution coefficient of Cs from tap water by mixed nickel-potassium ferrocyanide based on glauconite is 10(5.9±1.6) mL/g, static exchange capacity of Cs is (63.0±2.0) mg/g; for mixed nickel-potassium ferrocyanide based on clinoptilolite these characteristics are respectively 10(7.4±1.3) mL/g, 500 mg/g. In case of modified sorbents specificity to strontium remains the same as for natural aluminosilicates. Reversibility of sorption of caesium by natural glauconite and ferrocyanide sorbent was determined as caesium leaching degree from saturated samples. High caesium leaching rates and degrees are typical for natural glauconite irrespective of leachant salinity: total degree of leaching after 35 days of leaching was: mineral water = 63.4%, tap water = 41.6% and rain water = 28.8%. For

  13. Comparison of caesium 137 and 134 activity in sheep remaining on upland areas contaminated by Chernobyl fallout with those removed to less active lowland pasture

    Energy Technology Data Exchange (ETDEWEB)

    Howard, B.J.; Beresford, N.A.; Burrow, L.; Shaw, P.V.; Curtis, E.J.C.

    Caesium contamination of vegetation in some upland areas of the United Kingdom after the Chernobyl accident remained persistently higher than many anticipated. Consequently, some sheep continued to graze vegetation containing sufficiently high caesium activity to maintain tissue activity above the limits adopted for slaughter in the United Kingdom (1,000 Bq kg/sup -1/ fresh weight). In this study the caesium activity in lambs remaining on affected upland areas has been compared with that of lambs removed to a lowland site. The former lost very little caesium activity from the end of July to mid-September owing to the persistently high caesium activity of the pasture. The transfer coefficient to lamb muscle (0.79 day kg/sup -1/) was 6 times higher than that previously estimated from lowland field studies. Lambs removed to much less contaminated lowland pasture rapidly lost their Cs activity with an initial biological half life of 10 days.

  14. Orofacial manifestations from accidental exposure to caesium 137 in Goiania, Brazil.

    Science.gov (United States)

    Gomes, M A; Wascheck, C de C; Scully, C; Almeida, O de P; Bozzo, L

    1990-08-01

    The accidental close exposure of over 200 adults and children to a caesium-137 (137Cs) source in Goiania, Brazil in 1987 produced significant short-term morbidity in about 50 patients, and four deaths within a few weeks. Some 57% of those maximally exposed to radiation, developed orofacial lesions, notably purpura, spontaneous bleeding, ulcers and/or acute candidiasis. These lesions were probably mainly the consequences of depression of bone marrow elements by the radionuclide. Though the oral lesions that may follow iatrogenic exposure to ionizing radiation are well recognized this appears to be the first report on the oral sequelae of a serious radiation accident.

  15. The fate of caesium-137 in a soil environment controlled by immobilization on clay minerals

    OpenAIRE

    NAKAO, Atsushi; Funakawa, Shinya; Tsukada, Hirofumi; Kosaki, Takashi

    2012-01-01

    Caesium-137 (137Cs), with its high release rate and long half life, is the most important longterm contributor to environmental contamination of all the radionuclides released by the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. There have been many surveys of the fate of 137Cs in terrestrial environments, especially after the atmospheric nuclear tests of the 1950s and 60s and the Chernobyl accident in 1986. Previous surveys revealed that most of the 137Cs deposited on...

  16. Poly[μ3-aqua-aqua-μ5-(4-nitro­benzoato)-caesium

    OpenAIRE

    2013-01-01

    In the structure of the title complex, [Cs(C7H4NO2)(H2O)2]n, the caesium salt of 4-nitrobenzoic acid, the irregular CsO9 coordination sphere comprises three bridging nitro O-atom donors, a bidentate carboxylate O,O′-chelate interaction, a triple-bridging water molecule and a monodentate water molecule. A three-dimensional framework polymer is generated, within which there are water–carboxylate O—H...O and water–water O—H...O hydrogen-bonding interactions.

  17. A superradiant laser based on two-photon Raman transition of caesium atoms

    CERN Document Server

    Liu, Pengfei

    2013-01-01

    We propose a superradiant laser based on two-photon Raman transition of caesium-133 atoms which collectively emit photons on an ultra narrow transition into the mode of a low Q resonator known as optical bad-cavity regime. The spin-spin correlation which characterizes the collective effect is demonstrated. We theoretically predict that the optical radiation has an extremely narrow linewidth in the 98 (1) *10-2 mHz range, smaller than the transition itself due to collective effects, and a power level of 7 (1)*10-10 W is possible, which can provide a possible new way to realize an optical clock with a millihertz linewidth.

  18. Absorption spectroscopy of cold caesium atoms confined in a magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Yan Shu-Bin; Liu Tao; Geng Tao; Zhang Tian-Cai; Peng Kun-Chi; Wang Jun-Min

    2004-01-01

    Absorption spectra of cold caesium atoms confined in a magneto-optical trap are measured around D2 line at 852nm with a weak probe beam. Absorption reduction dip due to electromagnetically induced transparency (EIT)effect induced by the cooling/trapping field in a V-type three-level system and a gain peak near the cycling transition are clearly observed. Several mechanisms mixed with EIT effect in a normal V-type three-level system are briefly discussed. A simple theoretical analysis based on a dressed-state model is presented for interpretation of the absorption spectra.

  19. Poly[μ-aqua-μ5-[2-(2,3,6-trichlorophenylacetato]-caesium

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2013-12-01

    Full Text Available In the structure of the title complex, [Cs(C8H4Cl3O2(H2O]n, the caesium salt of the commercial herbicide fenac [(2,3,6-trichlorophenylacetic acid], the irregular eight-coordination about Cs+ comprises a bidentate O:Cl-chelate interaction involving a carboxylate-O atom and an ortho-related ring-substituted Cl atom, which is also bridging, a triple-bridging carboxylate-O atom and a bridging water molecule. A two-dimensional polymer is generated, lying parallel to (100, within which there are water–carboxylate O—H...O hydrogen-bonding interactions.

  20. Distributed cavity phase frequency shifts of the caesium fountain PTB-CSF2

    CERN Document Server

    Weyers, S; Nemitz, N; Li, R; Gibble, K

    2011-01-01

    We evaluate the frequency error from distributed cavity phase in the caesium fountain clock PTB-CSF2 at the Physikalisch-Technische Bundesanstalt with a combination of frequency measurements and ab initio calculations. The associated uncertainty is 1.3E-16, with a frequency bias of 0.4E-16. The agreement between the measurements and calculations explains the previously observed frequency shifts at elevated microwave amplitude. We also evaluate the frequency bias and uncertainty due to the microwave lensing of the atomic wavepackets. We report a total PTB-CSF2 systematic uncertainty of 4.1E-16.

  1. Poly[μ3-aqua-aqua-μ5-(4-nitrobenzoato-caesium

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2013-12-01

    Full Text Available In the structure of the title complex, [Cs(C7H4NO2(H2O2]n, the caesium salt of 4-nitrobenzoic acid, the irregular CsO9 coordination sphere comprises three bridging nitro O-atom donors, a bidentate carboxylate O,O′-chelate interaction, a triple-bridging water molecule and a monodentate water molecule. A three-dimensional framework polymer is generated, within which there are water–carboxylate O—H...O and water–water O—H...O hydrogen-bonding interactions.

  2. The radiation defect accumulation in scintillative crystals of caesium halides under intense electron beam irradiation

    CERN Document Server

    Galiy, P V

    1999-01-01

    The characteristics of defect accumulation and radiolysis at CsI crystals under mean energies of electron irradiation at wide dose rates and ranges of doses have been investigated by such methods: thermostimulated exoelectron emission (TSEE), Auger electron spectroscopy (AES) and optical absorption spectroscopy (OAS). The limit dose rates and absorbed doses of electron irradiation that lead to defects accumulation at room temperature in crystals volume and also surface stoichiometry violation have been evaluated. The doses of electron irradiation that lead to CsI radiolysis, with caesium coagulation in metallic phase have been determined. Some quasi periodic connection of such process with irradiation dose was observed.

  3. Distribution coefficients of caesium, chlorine, iodine, niobium, selenium and technetium on Olkiluoto soils

    Energy Technology Data Exchange (ETDEWEB)

    Soederlund, M.; Lusa, M.; Virtanen, S.; Vaelimaa, I.; Hakanen, M.; Lehto, J. [Univ. of Helsinki, Lab. of Radiochemistry (Finland); Lahdenperae, A.-M. [Saanio and Riekkola Oy, Helsinki (Finland)

    2014-02-15

    Retention of caesium, chlorine, iodine, niobium, selenium and technetium was investigated on soil samples from Olkiluoto using laboratory batch sorption experiments. Distribution coefficients were measured for both dried and sieved and untreated (wet, not sieved) mineral soil and humus in aerobic and anaerobic conditions. Mineralogical composition of the samples was determined by XRD-analysis. Caesium was sorbed efficiently on mineral soil samples and less efficiently on humus. Sorption decreased with decreasing cation exchange capacity and clay fraction content. The effect of competing cations decreased in the order Cs{sup +}>NH{sub 4}{sup +}>K{sup +}>Ca{sup 2+}>Na{sup +}. Chlorine was not retained by mineral soil samples, and the sorption was weak on humus. The sorption of iodine was the strongest on humus and the weakest on the untreated mineral soil samples in the anaerobic conditions. In the mineral soil samples, the sorption decreased with decreasing organic matter content and increasing pH. The retention of niobium on soil samples was the most efficient among the studied elements. The retention was high regardless of the aeration conditions. Sorption on humus was smaller. Selenium was retained efficiently on humus. Sorption on mineral soil samples was stronger in aerobic conditions. Sorption increased with time. Technetium was sorbed well on humus and anaerobic, untreated mineral soil samples. Sorption increased with increasing organic matter content and decreasing redox potential. The results from the sorption experiments are used in the site specific radionuclide migration modelling. (orig.)

  4. Caesium in high oxidation states and as a p-block element.

    Science.gov (United States)

    Miao, Mao-sheng

    2013-10-01

    The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry, rooted in the atomic shell structure. Within compounds, Group I elements, for example, invariably assume the +1 oxidation state, and their chemical properties differ completely from those of the p-block elements. These general rules govern our understanding of chemical structures and reactions. Here, first-principles calculations show that, under pressure, caesium atoms can share their 5p electrons to become formally oxidized beyond the +1 state. In the presence of fluorine and under pressure, the formation of CsF(n) (n > 1) compounds containing neutral or ionic molecules is predicted. Their geometry and bonding resemble that of isoelectronic XeF(n) molecules, showing a caesium atom that behaves chemically like a p-block element under these conditions. The calculated stability of the CsF(n) compounds shows that the inner-shell electrons can become the main components of chemical bonds.

  5. Micrometer-level naked-eye detection of caesium particulates in the solid state

    Directory of Open Access Journals (Sweden)

    Taizo Mori, Masaaki Akamatsu, Ken Okamoto, Masato Sumita, Yoshitaka Tateyama, Hideki Sakai, Jonathan P Hill, Masahiko Abe and Katsuhiko Ariga

    2013-01-01

    Full Text Available Large amounts of radioactive material were released from the Fukushima Daiichi nuclear plant in Japan, contaminating the local environment. During the early stages of such nuclear accidents, iodine I-131 (half-life 8.02 d is usually detectable in the surrounding atmosphere and bodies of water. On the other hand, in the long-term, soil and water contamination by Cs-137, which has a half-life of 30.17 years, is a serious problem. In Japan, the government is planning and carrying out radioactive decontamination operations not only with public agencies but also non-governmental organizations, making radiation measurements within Japan. If caesium (also radiocaesium could be detected by the naked eye then its environmental remediation would be facilitated. Supramolecular material approaches, such as host–guest chemistry, are useful in the design of high-resolution molecular sensors and can be used to convert molecular-recognition processes into optical signals. In this work, we have developed molecular materials (here, phenols as an optical probe for caesium cation-containing particles with implementation based on simple spray-on reagents and a commonly available fluorescent lamp for naked-eye detection in the solid state. This chemical optical probe provides a higher spatial resolution than existing radioscopes and gamma-ray cameras.

  6. Hydroxyapatite supported caesium carbonate as a new recyclable solid base catalyst for the Knoevenagel condensation in water

    Directory of Open Access Journals (Sweden)

    Monika Gupta

    2009-11-01

    Full Text Available The Knoevenagel condensation between aromatic aldehydes and malononitrile, ethyl cyanoacetate or malonic acid with hydroxyapatite supported caesium carbonate in water is described. HAP–Cs2CO3 was found to be a highly active, stable and recyclable catalyst under the reaction conditions.

  7. Caesium-137 as Indicator of Present Mass-Movement and Erosion Processes

    Science.gov (United States)

    Supper, R.; Baron, I.; Winkler, E.; Motschka, K.; Jaritz, W.; Moser, G.; Carman, M.

    2012-04-01

    After the Chernobyl atomic accident in April 1986, notable parts of Eastern, Northern and Central Europe were contaminated by Caesium-137 (137Cs). This radioactive isotope with 30.17 years half-life is completely of anthropogenic origin. After the accident it was transported through the atmosphere for long distances and contaminated the soil surface variably in the vast areas. Although much of the 137Cs content has already decayed, notable amounts can still be detected. The Department of Geophysics of the Geological Survey of Austria conducted in 2009 an airborne multi-sensor geophysical survey over three prominent landslides in Austria and Slovenia as a test study for the application of airborne geophysics for landslide investigations. Besides elelectromagnetic (subsurface resistivity) and passive microwave (soil moisture) measurements, a gamma ray survey was done; natural radioactive isotopes such as Potassium, Thorium, and Uranium were mapped. This paper deals only with the Caesium-137 distribution. The Gschliefgraben test site (N Austria) is a complex of active and dormant earthflows, landslides and rockfalls in a 4 km long valley at the foot of Northern Calcareous Alps within Ultrahelvetic and Rhenodanubian flysch rocks. The last major reactivation occurred in 2007 and 2008. Also the Sibratsgfäll test site (W Austria) is a complex of shallow and deep-seated landslides and earthflows in sedimentary rocks of the Helvetic Zone, Liebenstein Nappe, Feuerstätte Zone and the Rhenodanubian Flysch. Here the major recent reactivation occurred in May 1999 affecting the villages of Sibratsgfäll and Rindberg. The Stoze landslide (NW Slovenia) occurred in November 2000 and is situated in dolomitic to clayey and marly Upper Triassic rocks, in Quaternary glacial moraine sediments and slope debris. The Caesium-137 maps were compared to landslide inventory maps, airborne laser-scan DTMs and up-to-date orthophotos. In all of the test sites, the 137Cs minima correlated well

  8. Experimental observation of pump-probe spectra of caesium D2 line with a vapour cell

    Institute of Scientific and Technical Information of China (English)

    Wang Yan-Hua; Yang Hai-Jing; Zhang Tian-Cai; Wang Jun-Min

    2005-01-01

    Pump-probe spectra of caesium D2 line are experimentally investigated in a Cs atomic vapour cell with copropagating orthogonal linearly-polarized pump and probe laser beams. Absorption-reduction dips duo to electromagnetically induced transparency (EIT) in multi-A-type Zeeman sublevels of 6 S1/2 F=3-6 P3/2 F'=2 hyperfine transition and absorption-enhanced peaks due to electromagnetically induced absorption (EIA) in 6 S1/2 F=4-6 P3/2 F'=5 hyperfine transition are demonstrated. With detuned pump beam abnormal sign-reversed signals inside the EIT dip and the EIA peak are clearly observed.

  9. Five years hospital experience with the Amersham caesium 137 manual afterloading system

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, T.J.; Davy, T.J.; Skeggs, D.B.L. (Royal Free Hospital, London (UK))

    1983-06-01

    The Amersham caesium 137 manual afterloading system for treatment of cancer of the uterine cervix and endometrium has been in use at the Royal Free Hospital for more than five years. The system uses permanently loaded flexible source pencils in combination with standard packs of disposable plastic applicators. Both sources and applicators have proved trouble-free in use. The sources are transported in special containers designed and built at the Royal Free Hospital and are inserted and removed on the ward by nursing staff. A set of sources is used in theatre for rectal and bladder dose measurements when the applicators are inserted. Staff radiation doses are low. The system is mainly used to produce pear-shaped dose distributions similar to those of the Manchester system, but simple cylindrical distributions are possible using symmetrically loaded source pencils.

  10. Enhanced Raman sideband cooling of caesium atoms in a vapour-loaded magneto-optical trap

    CERN Document Server

    Li, Y; Feng, G; Nute, J; Piano, S; Hackermuller, L; Ma, J; Xiao, L; Jia, S

    2015-01-01

    We report enhanced three-dimensional degenerated Raman sideband cooling (3D DRSC) of caesium (Cs) atoms in a standard single-cell vapour-loading magneto-optical trap. Our improved scheme involves using a separate repumping laser and optimized lattice detuning. We load $1.5 \\times 10^7$ atoms into the Raman lattice with a detuning of -15.5 GHz (to the ground F = 3 state). Enhanced 3D DRSC is used to cool them from 60 $\\mu$K to 1.7 $\\mu$K within 12 ms and the number of obtained atoms is about $1.2 \\times 10^7$. A theoretical model is proposed to simulate the measured number of trapped atoms. The result shows good agreement with the experimental data. The technique paves the way for loading a large number of ultracold Cs atoms into a crossed dipole trap and efficient evaporative cooling in a single-cell system.

  11. Caesium carbonate as a highly efficient catalyst for the synthesis of macrocyclicdiamides

    Directory of Open Access Journals (Sweden)

    Esmael Rostami

    2014-07-01

    Full Text Available In this research work, we report the synthesis of macrocyclicdiamides from the reaction of diesters and aliphatic diamines in the presence of caesium carbonate. It has been demonstrated that among the carbonate of alkali metals (Li2CO3, Na2CO3, K2CO3 and CS2CO3, CS2CO3 appears to be the best catalyst for macrocyclization. Diesters with different substitution patterns on the aromatic ring reacted smoothly with diamines under optimal conditions, affording the corresponding macrocycles in high yields. Introducing a rigid group (e.g., sulfone on the substrate led to somewhat decreased yield. Various substrates proved to be suitable for this macrocyclization reaction, especially, the flexible ones.

  12. Isolation and identification of cobalt- and caesium-resistant bacteria from a nuclear fuel storage pond.

    Science.gov (United States)

    Dekker, Linda; Osborne, Thomas H; Santini, Joanne M

    2014-10-01

    One of the issues facing the nuclear power industry is how to store spent nuclear fuel which is contaminated with radionuclides produced during nuclear fission, including caesium ((134)Cs(+), (135)Cs(+) and (137)Cs(+)) and cobalt ((60)Co(2+)). In this study, we have isolated Co(2+)- and Cs(+)-resistant bacteria from water collected from a nuclear fuel storage pond. The most resistant Cs(+) and Co(2+) isolates grew in the presence of 500 mM CsCl and 3 mM CoCl2. Strain Cs67-2 is resistant to fourfold more Cs(+) than Cupriavidus metallidurans str. CH34 making it the most Cs(+)-resistant strain identified to date. The Cs(+)-resistant isolates were closely related to bacteria in the Serratia and Yersinia genera, while the Co(2+)-resistant isolates were closely related to the Curvibacter and Tardiphaga genera. These new isolates could be used for bioremediation.

  13. Enhanced Raman sideband cooling of caesium atoms in a vapour-loaded magneto-optical trap

    Science.gov (United States)

    Li, Y.; Wu, J.; Feng, G.; Nute, J.; Piano, S.; Hackermüller, L.; Ma, J.; Xiao, L.; Jia, S.

    2015-05-01

    We report enhanced three-dimensional degenerated Raman sideband cooling (3D DRSC) of caesium (Cs) atoms in a standard single-cell vapour-loaded magneto-optical trap. Our improved scheme involves using a separate repumping laser and optimized lattice detuning. We load 1.5 × 107 atoms into the Raman lattice with a detuning of -15.5 GHz (to the ground F = 3 state). Enhanced 3D DRSC is used to cool them from 60 µK to 1.7 µK within 12 ms and the number of obtained atoms is about 1.2 × 107. A theoretical model is proposed to simulate the measured number of trapped atoms. The result shows good agreement with the experimental data. The technique paves the way for loading a large number of ultracold Cs atoms into a crossed dipole trap and efficient evaporative cooling in a single-cell system.

  14. Observation of four-wave mixing in caesium atoms using a noncycling transition

    Institute of Scientific and Technical Information of China (English)

    Wang Li-Rong; Ma Jie; Zhao Jian-Ming; Xiao Lian-Tuan; Jia Suo-Tang

    2006-01-01

    In this paper the generation of four-wave mixing (FWM) signal using a noncycling transition of caesium atoms is investigated when the pumping laser is locked to the transition 6S1/2F = 4 → 6P3/2F' = 4, and meanwhile the probe frequency is scanned across the 6S1/2F = 4 → 6P3/2 transition. The efficiency of the four-wave mixing signal as a function of the intensity of the pumping beams and the detuning of the pumping beams is also studied. In order to increase the detection efficiency, a repumping laser which is resonant with 6S1/2F = 3 → 6P3/2F' = 4 transition is used. A theoretical model is also introduced, and the theoretical results are in qualitative agreement with experimental ones.

  15. Caesium oven design and R and D for the SPIDER beam source

    Energy Technology Data Exchange (ETDEWEB)

    Rizzolo, Andrea, E-mail: andrea.rizzolo@igi.cnr.it [Consorzio RFX, Euratom-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy); Pavei, Mauro; Pomaro, Nicola [Consorzio RFX, Euratom-ENEA Association, Corso Stati Uniti 4, 35127 Padova (Italy)

    2013-10-15

    Highlights: ► The work describes the Cs oven design and its integration in the SPIDER negative ion beam source. ► Thermal and mechanical simulations have been carried out supporting the design. ► The oven features diagnostics monitoring temperatures and the remaining Cs amount. ► The Cs amount monitor relies on an electrical resistance varying with level in the reservoir. ► A proof of concept of the novel Cs level measurement system is given and demonstrate its feasibility. -- Abstract: In the ITER neutral beam injectors caesium will be used in the negative ion source to enhance the ion yield, by lowering the surface work function, and to reduce the co-extracted electrons. Fresh Cs has to be deposited almost continuously inside the plasma source and its injection is obtained by means of Cs ovens. Three independent Cs ovens have been integrated in the SPIDER (Source for Production of Ion of Deuterium Extracted from Rf plasma) beam source (BS). Since the entire BS is in-vacuum, a completely new design of the Cs ovens was required, assuring their vacuum and high temperature compatibility, and remote operation. They feature an ON–OFF valve and two independent heating systems to control the Cs evaporation and to avoid vapour condensing on the injection duct, by controlling the temperature. A Cs level indicator to measure the quantity of liquid caesium inside the reservoir, based on the electric resistance variation of an electrode, is proposed for the first time and a proof of concept is given. The oven design and the R and D activity on the level measurement system are presented.

  16. Crystal structure of caesium hydrogen (L)-aspartate and an overview of crystalline compounds of aspartic acid with inorganic constituents

    Energy Technology Data Exchange (ETDEWEB)

    Fleck, M. [Universitaet Wien (Austria). Institut fuer Mineralogie und Kristallographie; Emmerich, R.; Bohaty, L. [Universitaet zu Koeln (Austria). Institut fuer Kristallographie

    2010-08-15

    The crystal structure of the new polar compound caesium hydrogen (L)-aspartate, Cs(C{sub 4}H{sub 6}NO{sub 4}), (abbreviated: Cs(L -AspH)) was determined from single crystal X-ray diffraction data; it comprises two crystallographically different L -AspH anions that are connected via caesium cations to form a three dimensional framework. The Cs ions are irregularly sevenfold[Cs1O{sub 7}] respectively eightfold[Cs2O{sub 8}] coordinated to all {alpha}- and {beta}- carboxylate oxygen atoms. Cs(L -AspH) represents a novel structure type of its own, as do most compounds of (L)-aspartic acid with inorganic constituents. A brief summary of such structurally known aspartates is given. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Uptake and retention of radio-caesium in earthworms cultured in soil contaminated by the Fukushima nuclear power plant accident.

    OpenAIRE

    Fujiwara, K.; T. Takahashi; P. Nguyen; Kubota, Y.; Gamou, S; Sakurai, S; Takahashi, S

    2015-01-01

    To understand the effects of radionuclides on non-human biota and the environment, it is essential to study the intake and metabolism of radio-isotopes in earthworms which are among the most important soil organisms, and Eisenia fetida, which were used in this study, are known to be sufficiently sensitive to chemicals and representative of common earthworms. In this study, we assessed the concentration ratios, uptake and retention, absorbed dose rate, and distribution of radio-caesium in eart...

  18. Magnetic Field Gradiometer with Sub-Micron Spatial Resolution Based on Caesium Vapour in an Extremely Thin Cell

    Directory of Open Access Journals (Sweden)

    Auzinsh M.

    2015-06-01

    Full Text Available In this paper we present a device for measuring the magnetic field and its gradient with a spatial resolution of several hundred nanometres. This device is based on caesium metal vapour confined to an extremely thin cell (ETC. To measure magnetic signals, we use absorption and very low laser powers, which might be appealing for modern fabrication techniques. A portable, fully automated device was constructed.

  19. Activity concentrations of (137)Caesium and (210)Polonium in seafood from fishing regions of New Zealand and the dose assessment for seafood consumers.

    Science.gov (United States)

    Pearson, Andrew J; Gaw, Sally; Hermanspahn, Nikolaus; Glover, Chris N

    2016-01-01

    A study was undertaken to determine activity concentrations for (134)Caesium, (137)Caesium and (210)Polonium in New Zealand seafood, and establish if activity concentrations varied with respect to species/ecological niche and coastal region. Thirty seafood samples were obtained from six fishing regions of New Zealand along with a further six samples of two commercially important species (hoki and arrow squid) with well-defined fisheries. (134)Caesium was not detected in any sample. (137)Caesium was detected in 47% of samples, predominantly in pelagic fish species, with most activities at a trace level. Detections of (137)Caesium were evenly distributed across all regions. Activity concentrations were consistent with those expected from the oceanic inventory representing residual fallout from global nuclear testing. (210)Polonium was detected above the minimum detectable concentration in 33 (92%) of the analysed samples. Molluscs displayed significantly elevated activity concentrations relative to all other species groups. No significant regional variation in activity concentrations were determined. Two dose assessment models for high seafood consumers were undertaken. Dose contribution from (137)Caesium was minimal and far below the dose exemption limit of 1 mSv/year. Exposure to (210)Polonium was significant in high seafood consumers at 0.44-0.77 mSv/year (5th-95th percentile). (137)Caesium is concluded to be a valuable sentinel radionuclide for monitoring anthropogenic releases, such as global fallout and reactor releases, in the marine environment. (210)Polonium is of importance as a natural radionuclide sentinel due to its high contribution to dietary committed dose in seafood consumers.

  20. Transmutation of ABO4 compounds incorporating technetium-99 and caesium-137

    Science.gov (United States)

    Kuo, E. Y.; Qin, M. J.; Thorogood, G. J.; Huai, P.; Ren, C. L.; Lumpkin, G. R.; Middleburgh, S. C.

    2017-02-01

    The stability of a series of {AB}{{{O}}}4 minerals incorporating radioactive {}99{Tc} during the latter’s β-decay to {}99{Ru} was investigated theoretically using density functional theory (DFT) computations. The compounds investigated were {{KTcO}}4, {{RbTcO}}4 and {{CsTcO}}4. The stability of the latter, {{CsTcO}}4, during transmutation, when the caesium consists of the radioactive isotope {}137{Cs}, was also investigated. For each of the compounds, two similar possible crystal structure types—scheelite and pseudoscheelite—were considered. As the {}99{Tc} decays, or the {}137{Cs} decays to {}137{Ba}, reaction enthalpies were calculated for possible decompositions or precipitations of the transmuting compounds. All the possible decompositions or precipitations investigated had positive reaction enthalpies, suggesting that the transmuting compounds are all chemically stable. Volume and lattice parameter changes, however, suggest that {{KTcO}}4 would also be structurally stable during transmutation to {{KRuO}}4, but that {{CsTcO}}4 would not be structurally stable during its transmutation to {{BaRuO}}4.

  1. Mapping of caesium fallout from the Chernobyl accident in the Jotunheimen area

    Energy Technology Data Exchange (ETDEWEB)

    Baranwal, Vikas C.; Ofstad, Frode; Roenning, Jan S.; Watson, Robin J.

    2011-07-01

    As a consequence of the Chernobyl accident, several areas in Norway received radioactive fallout. One of these areas is the eastern part of Jotunheimen in central Norway. Immediately after the accident in 1986, the Geological Survey of Norway (NGU) performed airborne gamma-ray spectroscopy in central Norway. At that time, it was not possible to calculate reliable radionuclide concentrations, and the data were presented as total counts per second. Several man-made radionuclides were present in the initial fallout, but due to short half-lives, most of these have now disintegrated into stable isotopes. 137Cs, with a half-life of 11.000 days ({approx} 30 years) is still present in the environment in significant quantities, leading to high radioactivity levels in meat from reindeer and sheep. To obtain a detailed map of the caesium fallout concentration in Jotunheimen, an airborne gamma-ray spectrometry (AGRS) survey was carried out, focussing on reindeer grazing areas. This project was a cooperation between Reindeer Husbandry Administration, Norwegian Radiation Protection Authority and the Geological Survey of Norway. (auth)

  2. [The importance of gamma irradiations with caesium-137 for Hyalomma anatolicum anatolicum (Metastigmata, Ixodidae) control].

    Science.gov (United States)

    Karaer, Zafer; Kar, Sirri; Düzgün, Ali; Güven, Esin; Pekmezci, Zafer; Emre, Zişan

    2006-01-01

    In this study, male ticks belonging to the Hyalomma anatolicum anatolicum species were subjected to gamma radiation doses of 5, 10, 15, 20 and 50 Gy, emitted by a gamma-ray source of Caesium 137. In females that fed with these male ticks, proportional to the increase in radiation dose, the period of feeding was found to shorten. A decrease was demonstrated in the number of engorged female ticks, engorgement weights, number of laying ticks and number of eggs. The hatching period of larvae from eggs was found to increase despite the decrease in the number of hatched larvae. Moreover no larvae were observed to hatch from any of the eggs of female ticks treated with a radiation dose of 50 Gy. Similarly, proportional to the applied dose of radiation, rates of viability and activity were observed to decrease in male ticks. In conclusion, taking into consideration the feeding periods and fertility rates of female ticks as indicators of male activity, this study has demonstrated that in combating with H. anatolicum anatolicum, radiation may be successful and a radiation dose of 10 Gy is most favorable.

  3. Evidence for Efimov quantum states in an ultracold gas of caesium atoms.

    Science.gov (United States)

    Kraemer, T; Mark, M; Waldburger, P; Danzl, J G; Chin, C; Engeser, B; Lange, A D; Pilch, K; Jaakkola, A; Nägerl, H-C; Grimm, R

    2006-03-16

    Systems of three interacting particles are notorious for their complex physical behaviour. A landmark theoretical result in few-body quantum physics is Efimov's prediction of a universal set of bound trimer states appearing for three identical bosons with a resonant two-body interaction. Counterintuitively, these states even exist in the absence of a corresponding two-body bound state. Since the formulation of Efimov's problem in the context of nuclear physics 35 years ago, it has attracted great interest in many areas of physics. However, the observation of Efimov quantum states has remained an elusive goal. Here we report the observation of an Efimov resonance in an ultracold gas of caesium atoms. The resonance occurs in the range of large negative two-body scattering lengths, arising from the coupling of three free atoms to an Efimov trimer. Experimentally, we observe its signature as a giant three-body recombination loss when the strength of the two-body interaction is varied. We also detect a minimum in the recombination loss for positive scattering lengths, indicating destructive interference of decay pathways. Our results confirm central theoretical predictions of Efimov physics and represent a starting point with which to explore the universal properties of resonantly interacting few-body systems. While Feshbach resonances have provided the key to control quantum-mechanical interactions on the two-body level, Efimov resonances connect ultracold matter to the world of few-body quantum phenomena.

  4. Genome-wide analysis of caesium and strontium accumulation in Saccharomyces cerevisiae.

    Science.gov (United States)

    Heuck, Sabine; Gerstmann, Udo C; Michalke, Bernhard; Kanter, Ulrike

    2010-10-01

    (137)Cs and (90)Sr contribute to significant and long-lasting contamination of the environment with radionuclides. Due to their relatively high biological availability, they are transferred rapidly into biotic systems and may enter the food chain. In this study, we analysed 4862 haploid yeast knockout strains of Saccharomyces cerevisiae to identify genes involved in caesium (Cs(+)) and/or strontium (Sr(2+)) accumulation. According to this analysis, 212 mutant strains were associated with reproducible altered Cs(+) and/or Sr(2+) accumulation. These mutants were deficient for a wide range of cellular processes. Among those, the vacuolar function and biogenesis turned out to be crucial for both Cs(+) and Sr(2+) accumulation. Disruption of the vacuole diminished Cs(+) accumulation, whereas Sr(2+) enrichment was enhanced. Further analysis with a subset of the identified candidates were undertaken comparing the accumulation of Cs(+) and Sr(2+) with their essential counterparts potassium (K(+)) and calcium (Ca(2+)). Sr(2+) and Ca(2+) accumulation was highly correlated in yeast excluding the possibility of a differential regulation or uptake mechanisms. In direct contrast, the respective results suggest that Cs(+) uptake is at least partially dependent on mechanisms distinct from K(+) uptake. Single candidates (e.g. KHA1) are presented which might be specifically responsible for Cs(+) homeostasis.

  5. Radiative heat transfer in plasma of pulsed high pressure caesium discharge

    Science.gov (United States)

    Lapshin, V. F.

    2016-01-01

    Two-temperature many component gas dynamic model is used for the analysis of features of radiative heat transfer in pulsed high pressure caesium discharge plasma. It is shown that at a sufficiently high pressure the radial optical thickness of arc column is close to unit (τR (λ) ∼ 1) in most part of spectrum. In this case radiative heat transfer has not local character. In these conditions the photons which are emitted in any point of plasma volume are absorbed in other point remote from an emission point on considerable distance. As a result, the most part of the electric energy put in the discharge mainly near its axis is almost instantly redistributed on all volume of discharge column. In such discharge radial profiles of temperature are smooth. In case of low pressure, when discharge plasma is optically transparent for own radiation in the most part of a spectrum (τR(λ) << 1), the emission of radiation without reabsorption takes place. Radiative heat transfer in plasma has local character and profiles of temperature have considerable gradient.

  6. Low-threshold amplified spontaneous emission and lasing from colloidal nanocrystals of caesium lead halide perovskites

    Science.gov (United States)

    Yakunin, Sergii; Protesescu, Loredana; Krieg, Franziska; Bodnarchuk, Maryna I.; Nedelcu, Georgian; Humer, Markus; de Luca, Gabriele; Fiebig, Manfred; Heiss, Wolfgang; Kovalenko, Maksym V.

    2015-08-01

    Metal halide semiconductors with perovskite crystal structures have recently emerged as highly promising optoelectronic materials. Despite the recent surge of reports on microcrystalline, thin-film and bulk single-crystalline metal halides, very little is known about the photophysics of metal halides in the form of uniform, size-tunable nanocrystals. Here we report low-threshold amplified spontaneous emission and lasing from ~10 nm monodisperse colloidal nanocrystals of caesium lead halide perovskites CsPbX3 (X=Cl, Br or I, or mixed Cl/Br and Br/I systems). We find that room-temperature optical amplification can be obtained in the entire visible spectral range (440-700 nm) with low pump thresholds down to 5+/-1 μJ cm-2 and high values of modal net gain of at least 450+/-30 cm-1. Two kinds of lasing modes are successfully observed: whispering-gallery-mode lasing using silica microspheres as high-finesse resonators, conformally coated with CsPbX3 nanocrystals and random lasing in films of CsPbX3 nanocrystals.

  7. Progress of the ELISE test facility: results of caesium operation with low RF power

    Science.gov (United States)

    Franzen, P.; Fantz, U.; Wünderlich, D.; Heinemann, B.; Riedl, R.; Kraus, W.; Fröschle, M.; Ruf, B.; Nocentini, R.; the NNBI Team

    2015-05-01

    The Max-Planck-Institut für Plasmaphysik test facility ELISE is an important intermediate step towards the in-time realization of the ITER neutral beam injection system (NBI). ELISE is equipped with a large radio-frequency (RF) driven negative hydrogen ion source (1 × 0.9 m2) of half the size of the ITER NBI source. The paper reports on the main results of the very first operation of the source with caesium, but with low RF power, both for hydrogen and deuterium, with pulse lengths of up to 500 s. The results are rather encouraging for the achievement of the required ITER NBI parameters, especially in hydrogen, where large current densities with respect to the low RF power could be achieved at a ratio of co-extracted electrons to extracted ions of 0.5-0.6 at the relevant source pressure of 0.3 Pa. The required magnetic filter field was significantly lower than expected from the experience with the prototype RF source. Similar large extracted ion currents could be achieved also in deuterium, but with larger amounts of co-extracted electrons. Here, the required ratio of co-extracted electrons to extracted ions of one could be achieved only in short pulses.

  8. Radioactive caesium in Boreal forest landscapes - Dynamics and transport in food webs. Summary of research 1986-1996

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, R.; Nylen, T.; Palo, T

    1998-12-01

    The need for - but also the paucity of - radioecological knowledge concerning the boreal forest became particularly apparent after the nuclear power plant accident in Chernobyl in April 1986. As a consequence several new projects were initiated in the Nordic countries with particular focus on the behaviour of radioactivecaesium in terrestrial and aquatic systems characteristic for the Fenno-Scandinavian landscapes. Among these new projects a multi-disciplinary co-operation in Umeaa between scientists at the Swedish University of Agricultural Sciences, and the Defence Research Establishment emerged. Initially this joint work focused mainly on descriptions of the dynamic changes of the content of radioactive caesium in soil-plant and animal communities in the county of Vaesterbotten. Most of the studies have been performed at the Vindeln experimental forest, 60 km NW of Umeaa. Plants of key interest were: bilberry (Vaccinium myrtillus), birch (Betula spp.), and pine (Pinus sylvestris), and among the animals: the moose (Alces alces) and a small rodent, the forest vole (Clethrionomus glareolus). Gradually over the past ten years the research has entered the stage where the specific causes of the caesium behaviour have been addressed - partly by the help of models developed for simulating forest ecosystems, partly by complementary field experiments. This paper reviews our main findings on this theme concerning the behaviour of radioactive caesium in boreal landscapes and significant pathways to man, as has become apparent from the radioecological co-operation dating from about ten years back. A list of the publications arising from these studies since 1986 is also presented in this report.

  9. Density functional theory metadynamics of silver, caesium and palladium diffusion at β-SiC grain boundaries

    Science.gov (United States)

    Rabone, Jeremy; López-Honorato, Eddie

    2015-03-01

    The use of silicon carbide in coated nuclear fuel particles relies on this materials impermeability towards fission products under normal operating conditions. Determining the underlying factors that control the rate at which radionuclides such as Silver-110m and Caesium-137 can cross the silicon carbide barrier layers, and at which fission products such as palladium could compromise or otherwise alter the nature of this layer, are of paramount importance for the safety of this fuel. To this end, DFT-based metadynamics simulations are applied to the atomic diffusion of silver, caesium and palladium along a Σ5 grain boundary and to palladium along a carbon-rich Σ3 grain boundary in cubic silicon carbide at 1500 K. For silver, the calculated diffusion coefficients lie in a similar range (7.04 × 10-19-3.69 × 10-17 m2 s-1) as determined experimentally. For caesium, the calculated diffusion rates are very much slower (3.91 × 10-23-2.15 × 10-21 m2 s-1) than found experimentally, suggesting a different mechanism to the simulation. Conversely, the calculated atomic diffusion of palladium is very much faster (7.96 × 10-11-7.26 × 10-9 m2 s-1) than the observed penetration rate of palladium nodules. This points to the slow dissolution and rapid regrowth of palladium nodules as a possible ingress mechanism in addition to the previously suggested migration of entire nodules along grain boundaries. The diffusion rate of palladium along the Σ3 grain boundary was calculated to be slightly slower (2.38 × 10-11-8.24 × 10-10 m2 s-1) than along the Σ5 grain boundary. Rather than diffusing along the precise plane of the boundary, the palladium atom moves through the bulk layer immediately adjacent to the boundary as there is greater freedom to move.

  10. The utilization of caesium 137 in studying soil degradation; L`utilisation du cesium 137 pour la connaissance de la degradation des sols

    Energy Technology Data Exchange (ETDEWEB)

    Wicherek, S.; Veyret, Y. [Centre de Biogeographie-Ecologie, 92 - Saint -Cloud (France); Bernard, C. [Ministere de l`Agriculture, des Pecheries et de l`Alimentation, Quebec (Canada)

    1994-12-31

    The caesium 137 isotope is distributed in the atmosphere during nuclear explosions, and is absorbed in the upper horizons of the soil on reaching the ground. When it is incorporated in the fine fraction of the soil, caesium 137 measurement allows movements affecting cultivated lands (mass movements, runoff effects, wind action) and rate of soil degradation over half a century to be evaluated. Vegetal cover and techniques of soil utilization must be considered; this method has been tested on a watershed in the Parisian Basin. 5 figs., 26 refs.

  11. Regional variation of caesium-137 in minke whales ¤Balaenoptera acutorostrata¤ from West Greenland, the Northeast Atlantic and the North Sea

    DEFF Research Database (Denmark)

    Born, E.W.; Dahlgaard, H.; Riget, F.F.

    2002-01-01

    Levels of radioactive caesium (Cs-137) were determined in minke whales (Balaenoptera acutorostrata) from West Greenland, the Northeast Atlantic region and the North Sea. The sample consisted of muscle tissue from 135 minke whales caught in 1998 in 7 different areas: West Greenland, n = 44; East...... caesium concentration in minke whales from the North Sea is in accordance with previous findings that Cs-137 levels in the marine environment of the North Atlantic region decrease with increasing distance from major point sources (i.e. nuclear-fuel reprocessing plants in the UK and France, and outflow...

  12. Low dose rate caesium-137 implant time of intracavitary brachytherapy source of a selected oncology center in Ghana

    OpenAIRE

    John Owusu Banahene; Emmanuel Ofori Darko; Baffour Awuah

    2015-01-01

    Background: The treatment time taken for a radioactive source is found to be very important in intracavitary brachytherapy treatment. The duration of the treatment time depends on the prescribed dose requested to a reference point and the calculated dose rate to the same point. The duration of the treatment time of source is found to depend on the tumour stage. In this work, the treatment time of implant has been calculated for a Caesium-137 low dose rate brachytherapy source at an oncology f...

  13. First performance results of PTB's atomic caesium fountain and a study of contributions to its frequency instability.

    Science.gov (United States)

    Weyers, S; Bauch, A; Hubner, U; Schroder, R; Tamm, C

    2000-01-01

    At the Physikalisch-Technische Bundesanstalt (PTB), an atomic caesium fountain was constructed. Ramsey fringes with a full width at half maximum (FWHM) of 0.86 Hz were obtained by launching the atoms to a height of 83 cm above the cooling region (40 cm above the microwave cavity center). A first measurement of the homogeneity of the magnetic flux density yields 0.33 nT (rms), only 0.16% of the mean value of 0.205 muT used in normal operation. The inherent elementary noise contributions of the fountain and of a thermal beam atomic clock are compared in some detail.

  14. Crystal structure of caesium dihydrogen citrate from laboratory X-ray powder diffraction data and DFT comparison

    Directory of Open Access Journals (Sweden)

    Alagappa Rammohan

    2017-02-01

    Full Text Available The crystal structure of caesium dihydrogen citrate, Cs+·H2C6H5O7−, has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The coordination polyhedra of the nine-coordinate Cs+ cations share edges to form chains along the a-axis. These chains are linked by corners along the c-axis. The un-ionized carboxylic acid groups form two different types of hydrogen bonds; one forms a helical chain along the c-axis, and the other is discrete. The hydroxy group participates in both intra- and intermolecular hydrogen bonds.

  15. Caesium-137 soil sampling and inventory variability in reference locations: A literature survey

    Science.gov (United States)

    Sutherland, Ross A.

    1996-01-01

    Soil sampling design, the number of samples collected and the lateral variation of caesium-137 (137Cs) in uneroded reference locations were extracted from previously published work. The focus was on published work which used 137Cs reference inventory (Bq m-2) for qualitative or quantitative estimation of sediment redistribution (SRD) within the landscape. The objective of this study was to address one of the methodological concerns facing the 137Cs technique - that is, the lack of a rigorous statistical treatment of reference locations. The limited attention paid to the reference location is not justified as true estimates of SRD are based on the assumption of an unbiased, independent, random probability sample estimate, commonly the arithmetic mean. Results from the literature survey indicated that only 11% of the reference locations sampled for 137Cs expressly stated that a probability sampling design was used (transect or systematic-aligned grid). The remaining locations were generally sampled using a non-probability based design, more commonly known as haphazard sampling. Of the 75 reference study areas identified only 40 provided enough information to determine the dispersion around the mean, and from this the coefficient of variation (CV) was calculated for all available data. The median CV was 19·3%, with 95% confidence limits of 13·0-23.4%, indicating that approximately 11 random, independent samples would generally be necessary to adequately quantify the reference 137Cs area activity with an allowable error of 10% at 90% confidence. Further analysis indicated that only one-third of the studies sampled a sufficient number of 137Cs reference locations. This value would actually be lower as sampling frameworks were based on non-probability sampling procedures. For 137Cs reference locations it is recommended that a probability sampling design be utilized, preferably the systematic-aligned grid method, and as a minimum first-order estimate about 11 samples

  16. Validation of the ICRP model for caesium intake by lactating mothers with Italian data after the Chernobyl fallout.

    Science.gov (United States)

    Giussani, Augusto; Risica, Serena

    2012-02-01

    In the aftermath of the Chernobyl nuclear power plant accident, a research group of the Italian National Institute of Health (Istituto Superiore di Sanità) carried out two research programmes on maternal milk. One concerned the transfer of caesium radionuclides from the diet to breast milk. In the other, the activity concentrations of (137)Cs were also determined in urine and placenta. The first study estimated the mothers' average (137)Cs dietary intake, in the second study the intake was evaluated individually for each subject. In 2004, the International Commission on Radiological Protection published modified systemic biokinetic models which also account for transfer to breast milk. The model for caesium radionuclides was implemented and tested by the authors with the experimental data described above. A good agreement was obtained between measured data and model simulations of (137)Cs activity concentration in human milk. The model, however, tends to systematically overestimate (137)Cs activity concentration in urine, in which case the agreement is to be considered satisfactory in terms of order of magnitude.

  17. Investigations on caesium-free alternatives for H{sup −} formation at ion source relevant parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kurutz, U.; Fantz, U. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); AG Experimentelle Plasmaphysik, Institut für Physik, Universität Augsburg, 86135 Augsburg (Germany)

    2015-04-08

    Negative hydrogen ions are efficiently produced in ion sources by the application of caesium. Due to a thereby induced lowering of the work function of a converter surface a direct conversion of impinging hydrogen atoms and positive ions into negative ions is maintained. However, due to the complex caesium chemistry and dynamics a long-term behaviour is inherent for the application of caesium that affects the stability and reliability of negative ion sources. To overcome these drawbacks caesium-free alternatives for efficient negative ion formation are investigated at the flexible laboratory setup HOMER (HOMogenous Electron cyclotron Resonance plasma). By the usage of a meshed grid the tandem principle is applied allowing for investigations on material induced negative ion formation under plasma parameters relevant for ion source operation. The effect of different sample materials on the ratio of the negative ion density to the electron density n{sub H{sup −}} /n{sub e} is compared to the effect of a stainless steel reference sample and investigated by means of laser photodetachment in a pressure range from 0.3 to 3 Pa. For the stainless steel sample no surface induced effect on the negative ion density is present and the measured negative ion densities are resulting from pure volume formation and destruction processes. In a first step the dependency of n{sub H{sup −}} /n{sub e} on the sample distance has been investigated for a caesiated stainless steel sample. At a distance of 0.5 cm at 0.3 Pa the density ratio is 3 times enhanced compared to the reference sample confirming the surface production of negative ions. In contrast for the caesium-free material samples, tantalum and tungsten, the same dependency on pressure and distance n{sub H{sup −}} /n{sub e} like for the stainless steel reference sample were obtained within the error margins: A density ratio of around 14.5% is measured at 4.5 cm sample distance and 0.3 Pa, linearly decreasing with

  18. The burden of cesium 137 in forest clerks; Die Belastung mit Caesium 137 bei Beschaeftigten der Forstverwaltung

    Energy Technology Data Exchange (ETDEWEB)

    Piechotowski, I.; Jaroni, J. [Landesgesundheitsamt Baden-Wuerttemberg, Stuttgart (Germany); Link, B. [Arbeits- und Sozialministerium des Landes Baden-Wuerttemberg, Stuttgart (Germany); Groezinger, O. [Ministerium fuer Umwelt und Verkehr des Landes Baden-Wuerttemberg, Stuttgart (Germany)

    2000-07-01

    In 47 forest clerks from the regions Ortenau and Oberschwaben in south-west Germany the incorporation of cesium 137 and potassium 40 was measured in autumn 1994. Soil burden as well as burden of nutrition with cesium 137 are different in these regions for geological reasons and as a result of the nuclear accident of Chernobyl. Caused by low content of clay in Oberschwaben, the transfer of cesium to plants is assisted. Heavy rainfall after the nuclear accident led to an additional increase of burden. The median of the concentration of cesium 137 was 1.4 Bq/kg body weight. The median for potassium 40 was 58 Bq/kg body weight. For cesium 137 regional differences were observed. For persons from Oberschwaben the median for cesium 137 was with 2.8 Bq/kg body weight clearly higher than for persons from Ortenau with 0,6 Bq/kg body weight. Concerning nutrition habits, the clearest difference was found comparing persons who had ate a minimum of four portions of deer from the surroundings within the last four weeks with persons who had ate less than four portions of deer from the surroundings within the last four weeks. The difference was greater in Oberschwaben than in Ortenau. The effective dose of cesium 137 calculated on the basis of the incorporation is very low compared to natural radiation. This is also valid for persons from Oberschwaben. (orig.) [German] Im Herbst 1994 wurde bei insgesamt 47 Bediensteten der Forstverwaltung aus den Regionen Ortenaukreis und Oberschwaben die Inkorportation an Caesium 137 und Kalium 40 gemessen. Sowohl die Bodenbelastung als auch die Belastung von Nahrungsmitteln mit Caesium 137 unterscheiden sich in diesen Gebieten bedingt durch geologische Besonderheiten und in Folge des Reaktorunfalls von Tschernobyl. Aufgrund eines geringen Anteils an Tonerden wird in Oberschwaben der Caesiumtransfer in Pflanzen beguenstigt, eine zusaetzliche Erhoehung der Belastung erfolgte durch starke Niederschlaege nach dem Reaktorunfall. Die Konzentration fuer

  19. Caesium fluoride-promoted Stille coupling reaction: an efficient synthesis of 9Z-retinoic acid and its analogues using a practical building block.

    Science.gov (United States)

    Okitsu, Takashi; Iwatsuka, Kinya; Wada, Akimori

    2008-12-21

    A highly efficient and rapid total synthesis of 9Z-retinoic acid was accomplished by caesium fluoride-promoted Stille coupling reaction; using a common building block, 9Z-retinoic acid analogues were also prepared by the same method without isomerisation of the Z-double bond.

  20. Density functional theory metadynamics of silver, caesium and palladium diffusion at β-SiC grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Rabone, Jeremy, E-mail: jeremy.rabone@ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, D-76125 Karlsruhe (Germany); López-Honorato, Eddie [Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV), Unidad Saltillo, Industria Metalúrgica 1062, Parque Industrial, Ramos Arizpe 25900, Coahuila (Mexico)

    2015-03-15

    Highlights: • DFT metadynamics of diffusion of Pd, Ag and Cs on grain boundaries in β-SiC. • The calculated diffusion rates for Pd and Ag tally with experimental release rates. • A mechanism of release other than grain boundary diffusion seems likely for Cs. - Abstract: The use of silicon carbide in coated nuclear fuel particles relies on this materials impermeability towards fission products under normal operating conditions. Determining the underlying factors that control the rate at which radionuclides such as Silver-110m and Caesium-137 can cross the silicon carbide barrier layers, and at which fission products such as palladium could compromise or otherwise alter the nature of this layer, are of paramount importance for the safety of this fuel. To this end, DFT-based metadynamics simulations are applied to the atomic diffusion of silver, caesium and palladium along a Σ5 grain boundary and to palladium along a carbon-rich Σ3 grain boundary in cubic silicon carbide at 1500 K. For silver, the calculated diffusion coefficients lie in a similar range (7.04 × 10{sup −19}–3.69 × 10{sup −17} m{sup 2} s{sup −1}) as determined experimentally. For caesium, the calculated diffusion rates are very much slower (3.91 × 10{sup −23}–2.15 × 10{sup −21} m{sup 2} s{sup −1}) than found experimentally, suggesting a different mechanism to the simulation. Conversely, the calculated atomic diffusion of palladium is very much faster (7.96 × 10{sup −11}–7.26 × 10{sup −9} m{sup 2} s{sup −1}) than the observed penetration rate of palladium nodules. This points to the slow dissolution and rapid regrowth of palladium nodules as a possible ingress mechanism in addition to the previously suggested migration of entire nodules along grain boundaries. The diffusion rate of palladium along the Σ3 grain boundary was calculated to be slightly slower (2.38 × 10{sup −11}–8.24 × 10{sup −10} m{sup 2} s{sup −1}) than along the Σ5 grain boundary. Rather

  1. Solvothermal Synthesis of Caesium Tungsten Bronze in the Presence of Various Organic Acids and Its NIR Absorption Properties

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Chongshen; Yin, Shu; Sato, Tsugio [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai (Japan); Adachi, Kenji; Chonan, Takeshi, E-mail: bigguop@mail.tagen.tohoku.ac.jp [Ichikawa Research Laboratory, Sumitomo Metal Mining Co., Ltd (Japan)

    2011-10-29

    Nanoparticles of caesium tungsten bronze were successfully synthesized by solvothermal reactions in ethanol with the introduction of different organic fatty acids with various carbon numbers of 1 to 5. Compared to the sample prepared in pure ethanol, the samples obtained by mixed solvent of ethanol and fatty acids showed higher production yield, smaller particle size, more uniform particles size distribution and higher Cs/W atomic ratio. In addition, all of samples obtained using acids-ethanol mixed solvent exhibited higher visible light transmittance and greater NIR absorption performance, indicating the potential application for smart window and heat-ray shielding materials. The addition of acetic acid showed the best performance to facilitate the formation of well dispersed Cs{sub x}WO{sub 3} regular nanorods, leading to its excellent optical properties.

  2. Ultra-high and persistent optical depths of caesium in Kagom\\'e-type hollow-core photonic crystal fibres

    CERN Document Server

    Kaczmarek, Krzysztof T; Sprague, Michael R; Kolthammer, W Steven; Feizpour, Amir; Ledingham, Patrick M; Brecht, Benjamin; Poem, Eilon; Abdolvand, Amir; Russell, Philip St J; Walmsley, Ian A; Nunn, Joshua

    2015-01-01

    Alkali-filled hollow-core fibres are a promising medium for investigating light-matter interactions, especially at the single-photon level, due to the tight confinement of light and high optical depths achievable by light-induced atomic desorption. However, until now these large alkali vapour densities could only be generated for seconds at most once per day, severely limiting the practicality of the technology. Here we report the generation of highest observed transient ($>10^5$ for minutes) and highest observed persistent (>2000 for hours) optical depths of alkali vapours in hollow-core fibres to date, using a caesium-filled Kagom\\'e-type hollow-core photonic crystal fibre. Our results pave the way to light-matter interaction experiments in confined geometries requiring long operation times and large atomic number densities, such as single-photon-level light-matter interaction experiments and fundamental investigations of hot dense atomic gases.

  3. Improved electron collection in fullerene via caesium iodide or carbonate by means of annealing in inverted organic solar cells

    Directory of Open Access Journals (Sweden)

    El Jouad Zouhair

    2014-05-01

    Full Text Available Inverted organic photovoltaic cells (IOPVCs, based on the planar heterojunction C60/CuPc, were grown using MoO3 as anode buffer layer and CsI or Cs2CO3 as cathode buffer layer (CBL, the cathode being an ITO coated glass. Work functions, Φf, of treated cathode were estimated using the cyclic voltammetry method. It is shown that Φf of ITO covered with a Cs compounds is decreased. This decrease is amplified by the annealing. It is shown that the thermal deposition under vacuum of the CBL induces a partial decomposition of the caesium compounds. In parallel, the formation of a compound with the In of ITO is put in evidence. This reaction is amplified by annealing, which allows obtaining IOPVCs with improved efficiency. The optimum annealing conditions is 150 °C for 5 min.

  4. New microwave excitation signal generating circuit for quantum frequency standard on the atoms of caesium Cs133

    Science.gov (United States)

    Petrov, A. A.; Davydov, V. V.

    2016-03-01

    In this work the study, design, development and experimental results of a new microwave excitation signal generating circuit are presented. New design of this circuit is based on the method of direct digital synthesis. The results of theoretical calculations and experimental researches show that the new design not only has a high precision, but also has an improvement in the spectral characteristics of the output signal. Range of generated output frequencies is expanded, that leads to the possibility of detuning the frequency of the neighboring resonance of spectral line and adjust the C-field in quantum frequency standard. Experimental research of the metrological characteristics of the quantum frequency standard on the atoms of caesium with a new functional unit showed an improvement in the daily frequency stability.

  5. Gigahertz optical memory with up to 20 dB gain via molecular quenching in caesium vapour

    CERN Document Server

    Thomas, S E; Kaczmarek, K T; Qiu, C; Brecht, B; Feizpour, A; Ledingham, P M; Walmsley, I A; Nunn, J; Saunders, D J

    2016-01-01

    Raman interactions in alkali vapours are used in applications such as atomic clocks, optical signal processing, generation of squeezed light and Raman quantum memories for temporal multiplexing. To achieve a strong interaction the alkali ensemble needs both a large optical depth and a high level of spin-polarisation. We implement a technique known as quenching using a molecular buffer gas which allows near-perfect spin-polarisation of over 99.5% in caesium vapour at high optical depths of up to $\\sim 10^5$; a factor of 4 higher than can be achieved without quenching. We use this system to explore efficient light storage with high gain in a GHz bandwidth Raman memory.

  6. Crystal structure of caesium di-hydrogen citrate from laboratory X-ray powder diffraction data and DFT comparison.

    Science.gov (United States)

    Rammohan, Alagappa; Kaduk, James A

    2017-02-01

    The crystal structure of caesium di-hydrogen citrate, Cs(+)·H2C6H5O7(-), has been solved and refined using laboratory X-ray powder diffraction data, and optimized using density functional techniques. The coordination polyhedra of the nine-coordinate Cs(+) cations share edges to form chains along the a-axis. These chains are linked by corners along the c-axis. The un-ionized carb-oxy-lic acid groups form two different types of hydrogen bonds; one forms a helical chain along the c-axis, and the other is discrete. The hy-droxy group participates in both intra- and inter-molecular hydrogen bonds.

  7. Experimental investigations on the caesium dynamics in H{sub 2}/D{sub 2} low temperature plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, Roland

    2014-10-15

    The fusion experiment ITER requires powerful neutral beam injection (NBI) systems for heating and current drive. The neutral beam with a power of 16.5 MW at an energy of 1 MeV is generated via accelerating negative hydrogen ions and subsequent neutralization in a gas target. A key component of the NBI system is the ion source which has to provide accelerated current densities of 200 A/m{sup 2} D{sup -} and 300 A/m{sup 2} H{sup -}. Such ion sources are currently under development and are based on the surface conversion mechanism: atoms and positive ions from a low temperature hydrogen plasma are converted into negative ions at a low work function surface, which is therefore coated with the alkali metal caesium. For that purpose Cs is introduced into the ion source via evaporation from a reservoir. Due to its high chemical reactivity, the adsorbed Cs layer is susceptible to impurities from the residual gas, which degrades the work function of the converter surface. Consequently, the stability and reliability of a high negative ion current density significantly depends on the Cs dynamics in the hydrogen plasma and in the vacuum phases between the pulses. In order to investigate the Cs dynamics on a fundamental level including plasma and surface chemistry, dedicated studies are performed in a flexible laboratory experiment under ion source relevant conditions. The inductively coupled plasma (ICP) setup is equipped with a comprehensive set of diagnostics to measure Cs fluxes, the Cs density, local and global plasma parameters, the work function of a sample surface as well as the impurity content. Owing to the strong Cs dynamics the diagnostics can moreover be applied simultaneously to relate parameters from different diagnostics to the same experimental condition. Furthermore, a reliable Cs source is developed, capable of stable Cs evaporation with well adjustable evaporation rates. The fundamental investigations have emphasized that the Cs dynamics in vacuum as well as

  8. Can inter-cultivar variation in caesium and strontium uptake reduce contamination of forage grasses? - Can inter-cultivar variation in caesium and strontium accumulation by forage grasses be used to reduce contamination of cows' milk in radiologically contaminated areas?

    Energy Technology Data Exchange (ETDEWEB)

    Penrose, B. [NERC Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Lancaster, LA1 4AP (United Kingdom); School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD (United Kingdom); Beresford, N. [NERC Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Lancaster, LA1 4AP (United Kingdom); Broadley, M.; Crout, N.M.J.; King, J.; Young, S. [School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD (United Kingdom); Lovatt, A. [Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, SY23 3E E (United Kingdom); Thomson, R. [Science and Advice for Scottish Agriculture (SASA), Roddinglaw Road, Edinburgh, EH12 9FJ (United Kingdom)

    2014-07-01

    Radiocaesium and radiostrontium primarily enter the food chain via plant root uptake, including indirectly via animal fodders. Inter-species variation in caesium and strontium accumulation in plants has previously been reported to be over two orders of magnitude. This variation could be exploited to select crops with relatively low uptake to reduce transfer of these radionuclides to consumers in contaminated areas. Exploiting intra-species (i.e. inter-cultivar) variation in caesium and strontium uptake has not yet been evaluated as a remediation strategy as sufficient data have not been available. As cows' milk has been one of the main contributors to human dose following the Chernobyl and Mayak accidents, we have chosen to focus on elucidating the extent and nature of inter-cultivar variation in caesium and strontium uptake in forage grasses. A total of 412 cultivars from four species of forage grass; perennial ryegrass (Lolium perenne; 284 cultivars), Italian ryegrass (Lolium multiflorum; 17 cultivars), hybrid ryegrass (Lolium hybridum; 101 cultivars) and tall fescue (Festuca arundinacea; 10 cultivars) were sampled from 20 sets of experimental plots in Aberystwyth (Wales, UK) and Edinburgh (Scotland, UK). Fifty-nine cultivars were grown in both locations. At least three replicates of the same cultivar were grown in each set of plots. Vegetation samples from 2208 plots were collected both in spring 2013 (May-June) and summer 2013 (August-September). The samples were oven-dried and milled then analysed for elemental composition using inductively coupled plasma mass spectrometry (ICP-MS). Stable caesium and strontium were measured as a proxy measurement for radiocaesium and radiostrontium concentrations. Concentrations of chemical analogues of caesium and strontium (potassium and calcium) and a number of other elements were measured. Soil samples from the experimental plots were also collected, dried, milled and analysed using ICP-MS. This paper will present

  9. RBE values for colo-rectal injury after caesium 137 gamma-ray and neutron irradiation. 1. Single doses

    Energy Technology Data Exchange (ETDEWEB)

    Terry, N.H.A.; Denekamp, J.; Maughan, R.L. (Mount Vernon Hospital, Northwood (UK). Gray Lab.)

    1983-04-01

    Colo-rectal damage in mice has been assessed after caesium ..gamma.. irradiation and 3 MeV neutrons given as single doses. Several assays were used, including body weight changes, faecal deformity and lethality. Dose response curves were constructed for each assay at times ranging from 10 days to 16 months after irradiation. An initial loss of weight at 10-20 days was presumably related to epithelial denudation, but a dose-dependent weight reduction (compared with controls) persisted over the animals' life span. Mice died progressively after localised pelvic ..gamma.. irradiation; there was no sharp demarcation between an early and late phase of lethal injury. Death resulted from intestinal stricture or stenosis. The time course for lethality was qualitatively different after neutron irradiation, with little progression of damage between 5 and 11 months. Faecal deformity was detectable as a higher proportion of small pellets when the rectum became constricted by fibrosis. No significant faecal deformity was observed before 6 months after which time dose response curves could be obtained. The RBE for early damage (assessed at 1-3 months) was 2.2-2.7, falling to 1.7-1.9 for late damage (determined at 10-15 months) over the range of neutron doses of 7.5-12 Gy.

  10. [Radiotherapy for carcinoma of the cervix by intermittent sessions with deferred loading using Cobalt 60 or Caesium 137 (author's transl)].

    Science.gov (United States)

    Swyngedauw, J

    1976-11-01

    Fractioning in gynaecological radiotherapy is a tolerance factor which may usefully be exploited in after loading. The advantage of fractioning is that it makes it possible to considerably increase the output of the projection apparatus (Curietron) and to avoid protection of the rooms : the patient retains the applicator in situ during the hospital stay and her bed is simply taken into the protected application room. With a source of 1 to 1.5 curie of cobalt, the author proposes twice-daily sessions of around ten minutes for ten days. Treatment may easily be given in the cobaltotherapy chamber. Using Caesium, it is necessary to protect only one room with a virtually two-fold increase in output since 10 to 12 hour treatments, either by day or by night, may be given. This very supple schedule makes it possible to modify dose and tolerance in relation to clinical conditions and the method of treatment (combined radiotherapy and surgery or radiotherapy alone). As far as axial vaginal source introducer is concerned, it is of prove, effectiveness as well as being easy to use. After describing the applicator, the source-carrier and the isodoses, the authors reviews the different methods of application, relying upon two previous studies of the influence of fractioning and protraction on tolerance (J. SWYNGEDAUW, 1975 and 1976).

  11. Caesium accumulation in yeast and plants is selectively repressed by loss of the SNARE Sec22p/SEC22.

    Science.gov (United States)

    Dräxl, Stephan; Müller, Johannes; Li, Wei B; Michalke, Bernhard; Scherb, Hagen; Hense, Burkhard A; Tschiersch, Jochen; Kanter, Ulrike; Schäffner, Anton R

    2013-01-01

    The non-essential cation caesium (Cs(+)) is assimilated by all organisms. Thus, anthropogenically released radiocaesium is of concern to agriculture. Cs(+) accumulates owing to its chemical similarity to the potassium ion (K(+)). The apparent lack of a Cs(+)-specific uptake mechanism has obstructed attempts to manipulate Cs(+) accumulation without causing pleiotropic effects. Here we show that the SNARE protein Sec22p/SEC22 specifically impacts Cs(+) accumulation in yeast and in plants. Loss of Saccharomyces cerevisiae Sec22p does not affect K(+) homeostasis, yet halves Cs(+) concentration compared with the wild type. Mathematical modelling of the uptake time course predicts a compromised vacuolar Cs(+) deposition in sec22Δ. Biochemical fractionation confirms this and indicates a new feature of Sec22p in enhancing non-selective cation deposition. A developmentally controlled loss-of-function mutant of the orthologous Arabidopsis thaliana SEC22 phenocopies the reduced Cs(+) uptake without affecting plant growth. This finding provides a new strategy to reduce radiocaesium entry into the food chain.

  12. Determining soil redistribution in Dian Lake catchment by combined use of caesium-137 and selected chemical properties

    Institute of Scientific and Technical Information of China (English)

    Zhang Mingli; Yang Hao; Xu Congan; Wang Yihong

    2009-01-01

    Recent development in the use of the environmental radionuclide caesium-137 for documenting rates and patterns of soil redistribution on the cultivated or uncultivated land and estimating rates of sediment deposition on floodplains represents an important advance that overcomes many of the limitations' of the conventional techniques commonly applied in such investigations.A study on soil redistribution (including soil erosion and deposition) was carried out in the Dian Lake catchment,Yunnan Province,using 137Cs and selected chemical properties.The average soil erosion rate was 1,280.2 t km-2yr-1.Soil erosion rate occurring on different parts of the slope was significantly different on different parts of the slope,increasing from the top,the bottom to the middle slope.The average soil erosion rate is also different with the land use type and that of the cultivated land (1,672.8 t km-2 yr-1) is higher than of the uncultivated land (1,161.2 t km-2yr-1).The result shows that landform,slope gradient and land use type are key factors that influence the size of soil erosion.In addition,we also find the SOC and TN contents and amount of the soil erosion to be correlated in the soil.With the soil erosion occurring,there are land degradation and the local eco-environmental problems,such as water eutrophication in Dian Lake

  13. Caesium 137: Properties and biological effects resulting of an internal contamination;Cesium 137: proprietes et effets biologiques apres contamination interne

    Energy Technology Data Exchange (ETDEWEB)

    Lestaevel, P.; Racine, R.; Bensoussan, H.; Rouas, C.; Gueguen, Y.; Dublineau, I.; Bertho, J.M.; Gourmelon, P.; Jourdain, J.R.; Souidi, M. [Institut de Radioprotection et de Surete Nucleaire, IRSN, laboratoire de radiotoxicologie experimentale, direction de la radioprotection de l' homme, 92 - Fontenay-aux-Roses (France)

    2010-02-15

    Caesium-137 ({sup 137}Cs) is a radionuclide present in the environment mainly as the result of the atmospheric nuclear weapons testing and accidents arising in nuclear power plants like the Chernobyl accident in 1986. Nowadays, the health consequences resulting from a chronic exposure to this radionuclide remain unknown. After absorption, the caesium is distributed relatively homogeneously within the body, with a more important load in children than in adults. The toxicity of {sup 137}Cs is mainly due to its radiological properties. A high dose of {sup 137}Cs is responsible for a medullar dystrophy, disorders of the reproductive function, and effects on liver and renal functions. Disorders of bone mineralization and brain damages were also described in human beings. At lowest dose, {sup 137}Cs induces disturbances of wakefulness-sleep cycle, but not accompanied with behavioural disorders. The cardiovascular system was also perturbed. Biological effects of {sup 137}Cs on the metabolisms of the vitamin D, cholesterol and steroid hormones were described, but do not lead to clinical symptoms. In human beings, {sup 137}Cs leads to an immune deficiency, congenital and foetal deformations, an increased of thyroid cancer, as well as neurological disorders. It seems that children are more sensitive to the toxic effects of caesium than the adults. At present, the only effective treatment for the decorporation of the ingested {sup 137}Cs is the Prussian Blue (Radiogardase). The use of pectin to de-corporate the ingested {sup 137}Cs, in children notably, is sometimes proposed, but its administration still remains an open question. To conclude, the available scientific data suggest that {sup 137}Cs could affect a number of physiological and metabolic functions and consequently, could participate in the health risks associated to the presence of other contaminants in the environment. (authors)

  14. Contribution to the use in analysis of ammonium phosphomolybdate- separation of radio-caesium in solution; Contribution a l'utilisation analytique du phosphomolybdate d'ammonium - separation du radiocesium en solution

    Energy Technology Data Exchange (ETDEWEB)

    Scheidhauer, J.; Chabidon, M.; Ordinaire, L. [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

    1964-07-01

    The use in analysis of ammonium phosphomolybdate has been studied for the separation of barium from caesium 137. The cases have been studied of small and medium-sized volumes, and of large volumes of about 100 litres. (authors) [French] L'utilisation analytique du phosphomolybdate d'ammonium est etudiee pour la separation du 137 caesium-baryum. Les cas des petits et moyens volumes et des grands volumes de l'ordre de 100 litres sont abordes successivement. (auteurs)

  15. Spectral anomalies of the effect of light-induced drift of caesium atoms caused by the velocity dependence of transport collision frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Parkhomenko, A I [Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation); Shalagin, A M [Novosibirsk State University, Novosibirsk (Russian Federation)

    2014-10-31

    The spectral features of the light-induced drift (LID) velocity of caesium atoms in inert buffer gases are studied theoretically. A strong temperature dependence of the spectral LID line shape of Cs atoms in Ar or Kr atmosphere in the vicinity of T ∼ 1000 K is predicted. It is shown that the anomalous LID of Cs atoms in binary buffer mixtures of two different inert gases can be observed at virtually any (including ambient) temperature, depending on the content of the components in these mixtures. The results obtained make it possible to precisely test the interatomic interaction potentials in the experiments on the anomalous LID. (quantum optics)

  16. A new approach to predicting environmental transfer of radionuclides to wildlife: A demonstration for freshwater fish and caesium

    Energy Technology Data Exchange (ETDEWEB)

    Beresford, N.A., E-mail: nab@ceh.ac.uk [NERC Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Av. Bailrigg, Lancaster LA1 4AP (United Kingdom); Yankovich, T.L. [Saskatchewan Research Council, Environment and Forestry, 125, 15 Innovation Blvd., Saskatoon, SK S7N 2X8 (Canada); Wood, M.D. [School of Environment and Life Sciences, Room 323, Peel Building, University of Salford, Manchester, M5 4WT (United Kingdom); Fesenko, S. [International Atomic Energy Agency, 1400 Vienna (Austria); Andersson, P. [Strålsäkerhetsnymdigheten, Swedish Radiation Safety Authority, SE-171 16 Stockholm (Sweden); Muikku, M. [STUK, P.O. Box 14, 00881 Helsinki (Finland); Willey, N.J. [Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol BS16 1QY (United Kingdom)

    2013-10-01

    The application of the concentration ratio (CR) to predict radionuclide activity concentrations in wildlife from those in soil or water has become the widely accepted approach for environmental assessments. Recently both the ICRP and IAEA have produced compilations of CR values for application in environmental assessment. However, the CR approach has many limitations, most notably, that the transfer of most radionuclides is largely determined by site-specific factors (e.g. water or soil chemistry). Furthermore, there are few, if any, CR values for many radionuclide-organism combinations. In this paper, we propose an alternative approach and, as an example, demonstrate and test this for caesium and freshwater fish. Using a Residual Maximum Likelihood (REML) mixed-model regression we analysed a dataset comprising 597 entries for 53 freshwater fish species from 67 sites. The REML analysis generated a mean value for each species on a common scale after REML adjustment taking account of the effect of the inter-site variation. Using an independent dataset, we subsequently test the hypothesis that the REML model outputs can be used to predict radionuclide, in this case radiocaesium, activity concentrations in unknown species from the results of a species which has been sampled at a specific site. The outputs of the REML analysis accurately predicted {sup 137}Cs activity concentrations in different species of fish from 27 Finnish lakes; these data had not been used in our initial analyses. We recommend that this alternative approach be further investigated for other radionuclides and ecosystems. - Highlights: • An alternative approach to estimating radionuclide transfer to wildlife is presented. • Analysed a dataset comprising 53 freshwater fish species collected from 67 sites. • Residual Maximum Likelihood mixed model regression is used. • Model output takes account of the effect of inter-site variation. • Successfully predicted {sup 137}Cs concentrations in

  17. Caesium-rich micro-particles: A window into the meltdown events at the Fukushima Daiichi Nuclear Power Plant

    Science.gov (United States)

    Furuki, Genki; Imoto, Junpei; Ochiai, Asumi; Yamasaki, Shinya; Nanba, Kenji; Ohnuki, Toshihiko; Grambow, Bernd; Ewing, Rodney C.; Utsunomiya, Satoshi

    2017-02-01

    The nuclear disaster at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011 caused partial meltdowns of three reactors. During the meltdowns, a type of condensed particle, a caesium-rich micro-particle (CsMP), formed inside the reactors via unknown processes. Here we report the chemical and physical processes of CsMP formation inside the reactors during the meltdowns based on atomic-resolution electron microscopy of CsMPs discovered near the FDNPP. All of the CsMPs (with sizes of 2.0–3.4 μm) comprise SiO2 glass matrices and ~10-nm-sized Zn–Fe-oxide nanoparticles associated with a wide range of Cs concentrations (1.1–19 wt% Cs as Cs2O). Trace amounts of U are also associated with the Zn–Fe oxides. The nano-texture in the CsMPs records multiple reaction-process steps during meltdown in the severe FDNPP accident: Melted fuel (molten core)-concrete interactions (MCCIs), incorporating various airborne fission product nanoparticles, including CsOH and CsCl, proceeded via SiO2 condensation over aggregates of Zn-Fe oxide nanoparticles originating from the failure of the reactor pressure vessels. Still, CsMPs provide a mechanism by which volatile and low-volatility radionuclides such as U can reach the environment and should be considered in the migration model of Cs and radionuclides in the current environment surrounding the FDNPP.

  18. Caesium-rich micro-particles: A window into the meltdown events at the Fukushima Daiichi Nuclear Power Plant

    Science.gov (United States)

    Furuki, Genki; Imoto, Junpei; Ochiai, Asumi; Yamasaki, Shinya; Nanba, Kenji; Ohnuki, Toshihiko; Grambow, Bernd; Ewing, Rodney C.; Utsunomiya, Satoshi

    2017-01-01

    The nuclear disaster at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011 caused partial meltdowns of three reactors. During the meltdowns, a type of condensed particle, a caesium-rich micro-particle (CsMP), formed inside the reactors via unknown processes. Here we report the chemical and physical processes of CsMP formation inside the reactors during the meltdowns based on atomic-resolution electron microscopy of CsMPs discovered near the FDNPP. All of the CsMPs (with sizes of 2.0–3.4 μm) comprise SiO2 glass matrices and ~10-nm-sized Zn–Fe-oxide nanoparticles associated with a wide range of Cs concentrations (1.1–19 wt% Cs as Cs2O). Trace amounts of U are also associated with the Zn–Fe oxides. The nano-texture in the CsMPs records multiple reaction-process steps during meltdown in the severe FDNPP accident: Melted fuel (molten core)-concrete interactions (MCCIs), incorporating various airborne fission product nanoparticles, including CsOH and CsCl, proceeded via SiO2 condensation over aggregates of Zn-Fe oxide nanoparticles originating from the failure of the reactor pressure vessels. Still, CsMPs provide a mechanism by which volatile and low-volatility radionuclides such as U can reach the environment and should be considered in the migration model of Cs and radionuclides in the current environment surrounding the FDNPP. PMID:28198440

  19. Accumulation of potassium, rubidium and caesium (133Cs and 137Cs in various fractions of soil and fungi in a Swedish forest.

    Science.gov (United States)

    Vinichuk, M; Taylor, A F S; Rosén, K; Johanson, K J

    2010-05-15

    Radiocaesium ((137)Cs) was widely deposited over large areas of forest in Sweden as a result of the Chernobyl accident in 1986 and many people in Sweden eat wild fungi and game obtained from these contaminated forests. In terms of radioisotope accumulation in the food chain, it is well known that fungal sporocarps efficiently accumulate radiocaesium ((137)Cs), as well as the alkali metals potassium (K), rubidium (Rb) and caesium (Cs). The fungi then enhance uptake of these elements into host plants. This study compared the accumulation of these three alkali metals in bulk soil, rhizosphere, soil-root interface, fungal mycelium and sporocarps of mycorrhizal fungi in a Swedish forest. The soil-root interface was found to be distinctly enriched in K and Rb compared with the bulk soil. Potassium concentrations increased in the order: bulk soilCaesium was more or less evenly distributed within the bulk soil, rhizosphere and soil-root interface fractions, but was actively accumulated by fungi. Fungi showed a greater preference for Rb and K than Cs, so the uptake of (137)Cs could be prevented by providing additional Rb or K at contaminated sites. The levels of K, Rb, and Cs found in sporocarps were at least one order of magnitude higher than those in fungal mycelium. These results provide new insights into the use of transfer factors or concentration ratios. The final step, the transfer of alkali metals from fungal mycelium to sporocarps, raised some specific questions about possible mechanisms.

  20. EFFICIENCY OF PROTECTIVE MEASURES TO REDUCE INTERNAL DOSE FROM CAESIUM RADIONUCLIDES FOR THE INHABITANTS OF RADIOACTIVE CONTAMINATION AREA IN THE FIRST YEARS AFTER THE CHERNOBYL ACCIDENT

    Directory of Open Access Journals (Sweden)

    I. G. Travnikova

    2012-01-01

    Full Text Available In the paper, we use the data on the content of caesium radionuclides in foodstuffs and in Bryansk region adult inhabitant’s body, on their food ration and its changes during the first years after the Chernobyl accident, and on the measures to protect the population from internal exposure. We calculate dynamics of 137Cs intake in the body and its contents therein, while maintaining a traditional diet and while replacing food products for radiationfree ones. The results show that the actual 137Cs content in the body is usually below the one calculated on the basis of the food ration. It was found out that individual 137Cs contents in the body correlate with the rate of meat, dairy and natural food products consumption and with factors of protection from internal exposure. The efficiency of the protective measures to reduce the intake and the content of caesium radionuclides in the body of inhabitants, as well as the average effective dose in the first years after the accident has been quantitatively assessed.

  1. Caesium absorption by barley - influence of its retention by the soil - competitive action of potassium; Absorption du cesium par l'orge - influence de sa retention dans le sol - action competitive du potassium

    Energy Technology Data Exchange (ETDEWEB)

    Ferron-Trosseau, F. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-06-01

    We have studied, in various culture media, how the absorption of caesium by barley varies with its concentration, and how this absorption can be in competition with a similar alkali cation-potassium. We have also considered the caesium distribution in the ground in particular radio-active caesium, between the soil and solution, as a function of the amount of caesium. From our work it is clear that barley behaves very differently according to whether the caesium is in a nutritive solution or is in the soil: for a nutritive solution, the fraction of caesium (radioactive and stable) absorbed by barley remains practically constant in the presence of increasing amounts (relatively small) of stable caesium; in soil, the fraction of the radio-active caesium absorbed increases as the stable caesium content (fairly low) of the soil increases, in relationship with a rapidly decreasing selectivity of the soil for Cs{sup +}. The difference between these results is thus explained by the very pronounced selectivity of the illitic soil studied for Cs{sup +}, as long as the proportion of Cs remains low, about as low as that of most natural soils. Furthermore, the K{sup +} ion is in competition with the Cs{sup +} ion, for absorption by barley in a culture medium in a nutritive solution or in soil, only when the potassium concentrations are relatively low, of the order of the nutritive maximum. This shows that the addition of potassium to a medium already rich in this element does not reduce the absorption of caesium by barley. The choice of experimental conditions close to natural conditions (nutritive media strong in calcium) and the examination of the distribution of radioactive caesium between the soil, the soil solution and the plant in the presence of very low doses of stable caesium make these results interesting from the 'atomic health' point of view; it should be expected that a definite contamination risk exists for plants cultivated on synthetic media and for

  2. Irradiation of members of the general public from radioactive caesium following the Chernobyl reactor accident: Field studies in a highly contaminated area in the Bryansk region, Russia

    Science.gov (United States)

    Thornberg, Charlotte

    From 1990 to 1998, estimations of the effective dose due to irradiation from 137Cs and 134Cs were carried out for inhabitants in rural villages in the Bryansk region, Russia. The villages, situated about 180 km from the Chernobyl power plant received deposition of 137Cs in the range 0.9-2.7 MBq m-2 due to the accident in 1986. The body burden of 137,134Cs was estimated from measurements of the urinary concentration of caesium radionuclides, together with in vivo measurements using a portable detector. The external effective dose was estimated from measurements with thermoluminescent (TL)-dosemeters worn by the participants during one month each year. In a case study, the changes in biokinetics of 137Cs during pregnancy was investigated in a woman with an unintended intake of 137Cs via mushrooms grown in the area. During pregnancy the biological half-time of caesium was 54% of that before pregnancy. The ratio of the 137Cs concentration in breast milk (Bq L-1) to that in the mother's body (Bq kg-1) was 15% one month after the child was born. The body burden of 137Cs in the Russian individuals calculated from urine samples showed a good agreement with the body burden estimated from in vivo measurements in the same individuals. Normalisation of the caesium concentration in the urine samples by the use of potassium or creatinine excretion introduced systematic differences and a larger spread in the calculated values of the 137Cs body burden as compared with calculations without normalisation. The yearly effective dose to inhabitants in the Russian villages varied between 1.2 and 2.5 mSv as a mean for all villages between 1991 and 1998 and the internal effective dose was 30-50% of the total effective dose. The external effective dose decreased on average 15% per year, while the internal effective dose varied, depending to a great extent on the availability of mushrooms. The cumulated effective dose for a 70-year period after the accident was calculated to be 100 m

  3. Monitoring of caesium-137 in food plants and muscle from moose, red deer and wild reindeer in 2010.; Overvaaking av cesium-137 i beitevekster og kjoett av elg, hjort og villrein i 2010.

    Energy Technology Data Exchange (ETDEWEB)

    Veiberg, Vebjoern; Gaare, Eldar; Stokke, Sigbjoern; Solberg, Erling J.; Skuterud, Lavrans

    2011-07-01

    The monitoring of Cs-137 fall-out from the Chernobyl accident in 1986, started the same year. Several plants and wild reindeer in natural ecosystems in Nord-Rondane have been followed annually ever since. Four more wild reindeer ranges were included in 2001: Setesdal-Ryfylkeheiene, Hardangervidda, Nord-Ottadalen, Snoehetta and Nord-Rondane. From 2007 Forollhogna was also included. On fixed plots in Nord-Rondane and Snoehetta some of the reindeer forage plants, including both higher plants and fruticose lichens, have been sampled and analyzed annually since 1986. This was also done in 2010. In addition plants and lichens were sampled at five locations along an altitudinal gradient at Soendre Knutshoe, and at 7-8 locations along an east-west gradient from Kollaflata to Skarhoe in the Jora valley continuing along the Aursjoe to Torbudalen. All these locations were sampled annually between 1987-1990, but they have not been sampled since. In 2010 samples from red deer and moose was also collected from eight different regions located within the following counties: Oppland, Telemark, Vest-Agder, Rogaland, Sogn and Fjordane, Nord-Troendelag, Nordland and Troms. Red deer were sampled in four regions and moose in six. Both species were sampled in Oppland. In 2010 76, 49 and 61 samples were collected from wild reindeer, red deer and moose respectively. All measures of caesium levels were performed on dried samples. For the 596 samples of plants and lichen the results refer to caesium-levels in dried samples. For the meat samples, results refer to caesium-137 levels in raw meat. Due to large variation in measured levels of caesium within species and sampling area, we give median values instead of mean values.The highest caesium levels in wild reindeer were found in Snoehetta (1010 Bq/kg) and Nord-Rondane (2686 Bq/kg). The levels found in the other areas were considerably lower. The highest caesium levels in both red deer (Sel, 677 Bq/kg) and moose (Vaaga, 365 Bq/kg) were found

  4. THE CONTENT OF CAESIUM-137 IN THE RIVERSIDE AND WATER VEGETATION VETKA AND CHECHERSK DISTRICTS OF THE GOMEL REGION OF BELARUS

    Directory of Open Access Journals (Sweden)

    N. M. Dajneko

    2014-01-01

    Full Text Available The content of radiocaesium was studied in 58 plant samples in 2 districts with only 12 (20,6% exceeding the allowable level which equals 370 Bk/kg. In Vetka district the highest specific activity of caesium-137 (Bk/kg was demonstrated by Equisetum arvense and Comarum palustre among the medium-sized euhydrophytes in  the  second  object,  which  3,7  and  5,2  times  exceeds  the  standard.   Ceratophyllum  demersum  has  the  highest accumulation coefficient. In Chechesk district medium-sized euhydrophytes Juncus effusus and Sium latifolium in the second object exceed the standard 7,8–2,2 times. Stratiotes aloides demonstrates the highest accumulation coefficient.

  5. Low dose rate caesium-137 implant time of intracavitary brachytherapy source of a selected oncology center in Ghana

    Directory of Open Access Journals (Sweden)

    John Owusu Banahene

    2015-01-01

    Full Text Available Background: The treatment time taken for a radioactive source is found to be very important in intracavitary brachytherapy treatment. The duration of the treatment time depends on the prescribed dose requested to a reference point and the calculated dose rate to the same point. The duration of the treatment time of source is found to depend on the tumour stage. In this work, the treatment time of implant has been calculated for a Caesium-137 low dose rate brachytherapy source at an oncology facility in Ghana. Objective: The objective was to determine how the treatment time of tumours depends on the dose rate to the reference point prescribed by the Oncologists and the dose rate determined by the dosimetrists at the facility. Materials and Method: Depending upon the stage of the cancer, the Oncologist determines the type of treatment modality, source configuration for the cancer patient and positions of both tandem and ovoids in the cervix. Depending also on the tumour stage, two orthogonal radiographic X-ray films are taken using a simulator machine. The treatment machine used in the study is AMRA-Curietron. The maximum activity of the source was 259GBq. It has five channels which is a manual remote afterloader. In clinical practice, the treatment time t is very short(only some few days for such low dose rate brachytherapy source like Cs-137 which lasts only for some few days in comparison with the half life of the Cs-137 source. The mathematical equation for the calculation of treatment time is written as t=D/D. Hence t is the treatment time of the radioactive source of patients undergoing intracavitary brachytherapy treatment, D is prescribed dose to a reference point and D is the dose rate to the same reference point. Results: The calculated treatment time of the Cs-137 brachytherapy source for different source arrangements or channels used in clinical practice at the brachytherapy Centre have been determined. Also provided, are the

  6. Caesium diuranium hexatelluride

    Directory of Open Access Journals (Sweden)

    Adel Mesbah

    2012-10-01

    Full Text Available Single crystals of CsU2Te6 were synthesized from the reaction of U, Te, and Cs2Te3 at 1273 K. CsU2Te6 crystallizes in the space group Cmcm in the CsTh2Te6 structure type. The asymmetric unit comprises one U (site symmetry m2m, one Cs (m2m; half-occupancy and two Te atoms (m.. and m2m. The structure of CsU2Te6 consists of infinite [U2Te6] layers perpendicular to [010] separated by Cs atoms. There are infinite Te—Te—Te linear chains along [001].

  7. Effects of fluvial processes in different order river valleys on redistribution and storage of particle-bound radioactive caesium-137 in area of significant Chernobyl fallout and impact on linked rivers with lower contamination levels

    Science.gov (United States)

    Belyaev, Vladimir; Golosov, Valentin; Shamshurina, Evgeniya; Ivanov, Maxim; Ivanova, Nadezhda; Bezukhov, Dmitry; Onda, Yuichi; Wakiyama, Yoshifumi; Evrard, Olivier

    2015-04-01

    Detailed investigations of the post-fallout fate of radionuclide contamination represent an important task in terms of environmental quality assessment. In addition, particle-bound radionuclides such as the most widespread anthropogenic isotope caesium-137 can be used as tracers for quantitative assessment of different sediment redistribution processes. In landscapes of humid plains with agriculture-dominated land use the post-fallout redistribution of caesium-137 is primarily associated with fluvial activity of various scales in cascade systems starting from soil erosion on cultivated hillslopes through gully and small dry valley network into different order perennial streams and rivers. Our investigations in the so-called Plavsk hotspot (area of very high Chernobyl caesium-137 contamination within the Plava River basin, Tula Region, Central European Russia) has been continuing for more than 15 years by now, while the time passed since the Chernobyl disaster and associated radioactive fallout (1986) is almost 29 years. Detailed information on the fluvial sediment and associated caesium-137 redistribution has been obtained for case study sites of different size from individual cultivated slopes and small catchments of different size (2-180 km2) to the entire Plava River basin scale (1856 km2). It has been shown that most of the contaminated sediment over the time passed since the fallout has remained stored within the small dry valleys of the 1-4 Hortonian order and local reservoirs (>70%), while only about 5% reached the 5-6 order valleys (main tributaries of the Plava River) and storage of the Plava floodplain itself represents as low as 0.3% of the basin-scale total sediment production from eroded cultivated hillslopes. Nevertheless, it has been shown that contaminated sediment yield from the Plava River basin exerts significant influence on less polluted downstream-linked river system. Recent progress of the investigations involved sampling of 7 detailed depth

  8. Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process. Penning-trap mass measurements of neutron-rich cadmium and caesium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, Dinko

    2016-07-06

    Although the theory for the rapid neutron-capture process (r-process) was developed more than 55 years ago, the astrophysical site is still under a debate. Theoretical studies predict that the r-process path proceeds through very neutron-rich nuclei with very asymmetric proton-to-neutron ratios. Knowledge about the properties of neutron-rich isotopes found in similar regions of the nuclear chart and furthermore suitable for r-process studies is still little or even not existing. The basic nuclear properties such as binding energies, half-lives, neutron-induced or neutron-capture reaction cross-sections, play an important role in theoretical simulations and can vary or even drastically alternate results of these studies. Therefore, a considerable effort was put forward to access neutron-rich isotopes at radioactive ion-beam facilities like ISOLDE at CERN. The goal of this PhD thesis is to describe the experimental work done for the precision mass measurements of neutron-rich cadmium ({sup 129-131}Cd) and caesium ({sup 132,146-148}Cs) isotopes. Measurements were done at the on-line radioactive ion-beam facility ISOLDE by using the four-trap mass spectrometer ISOLTRAP. The cadmium isotopes are key nuclides for the synthesis of stable isotopes around the mass peak A = 130 in the Solar System abundance.

  9. [Comparison of the ability to fertilize females by Hyalomma anatolicum anatolicum males irradiated with gamma radiation from caesium 137 with non-irradiated males].

    Science.gov (United States)

    Karaer, Zafer; Kar, Sirri; Düzgün, Ali; Güven, Esin; Cakmak, Ayşe; Emre, Zişan; Nalbantoğlu, Serpil; Saribaş, Taner; Akçay, Aytaç

    2009-01-01

    In this study, Hyalomma anatolicum anatolicum male ticks were subjected to gamma radiation with a dose of 10 Gy emitted by a gamma-ray source of Caesium 137. Female ticks were divided into 3 groups and placed in rabbit ears to feed. In the first group, the females fed with normal and irradiated males, in the second group females fed only with irradiated males and in last group females fed with normal males. Biological parameters such as the feeding period, weights, period of time from dropping until egg-laying began, the number of eggs and the number of larva hatching from eggs were recorded. With the results of statistical analysis it was found that the average egg laying period of females in the second group was clearly less (22.77 days) than other groups and the difference between these groups was statistically important (P < 0.05). After evaluation of numbers of larva, also there was a statistically important difference between the groups and the average number of larva was clearly higher (2519.30) in third group than other groups. In conclusion, in this study it was found that irradiated males could not compete with normal males in mating with females and because of this they couldn't affect the feeding and reproductivity of females.

  10. Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process Penning-trap mass measurements of neutron-rich cadmium and caesium isotopes

    CERN Document Server

    AUTHOR|(CDS)2085660; Litvinov, Yuri A.; Kreim, Susanne

    Although the theory for the rapid neutron-capture process (r-process) was developed more than 55 years ago, the astrophysical site is still under a debate. Theoretical studies predict that the r-process path proceeds through very neutron-rich nuclei with very asymmetric proton- to-neutron ratios. Knowledge about the properties of neutron-rich isotopes found in similar regions of the nuclear chart and furthermore suitable for r-process studies is still little or even not existing. The basic nuclear properties such as binding energies, half-lives, neutron-induced or neutron-capture reaction cross-sections, play an important role in theoretical simulations and can vary or even drastically alternate results of these studies. Therefore, a considerable effort was put forward to access neutron-rich isotopes at radioactive ion-beam facilities like ISOLDE at CERN. The goal of this PhD thesis is to describe the experimental work done for the precision mass measurements of neutron-rich cadmium (129−131 Cd) and caesium...

  11. Microhydration of caesium compounds: Cs, CsOH, CsI and Cs₂I₂ complexes with one to three H₂O molecules of nuclear safety interest.

    Science.gov (United States)

    Sudolská, Mária; Cantrel, Laurent; Cernušák, Ivan

    2014-04-01

    Structure and thermodynamic properties (standard enthalpies of formation and Gibbs free energies) of hydrated caesium species of nuclear safety interest, Cs, CsOH, CsI and its dimer Cs₂I₂, with one up to three water molecules, are calculated to assess their possible existence in severe accident occurring to a pressurized water reactor. The calculations were performed using the coupled cluster theory including single, double and non-iterative triple substitutions (CCSD(T)) in conjunction with the basis sets (ANO-RCC) developed for scalar relativistic calculations. The second-order spin-free Douglas-Kroll-Hess Hamiltonian was used to account for the scalar relativistic effects. Thermodynamic properties obtained by these correlated ab initio calculations (entropies and thermal capacities at constant pressure as a function of temperature) are used in nuclear accident simulations using ASTEC/SOPHAEROS software. Interaction energies, standard enthalpies and Gibbs free energies of successive water molecules addition determine the ordering of the complexes. CsOH forms the most hydrated stable complexes followed by CsI, Cs₂I₂, and Cs. CsOH still exists in steam atmosphere even at quite high temperature, up to around 1100 K.

  12. Sensitivity of the modelled deposition of Caesium-137 from the Fukushima Dai-ichi nuclear power plant to the wet deposition parameterisation in NAME.

    Science.gov (United States)

    Leadbetter, Susan J; Hort, Matthew C; Jones, Andrew R; Webster, Helen N; Draxler, Roland R

    2015-01-01

    This paper describes an investigation into the impact of different meteorological data sets and different wet scavenging coefficients on the model predictions of radionuclide deposits following the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. Three separate operational meteorological data sets, the UK Met Office global meteorology, the ECMWF global meteorology and the Japan Meteorological Agency (JMA) mesoscale meteorology as well as radar rainfall analyses from JMA were all used as inputs to the UK Met Office's dispersion model NAME (the Numerical Atmospheric-dispersion Modelling Environment). The model predictions of Caesium-137 deposits based on these meteorological models all showed good agreement with observations of deposits made in eastern Japan with correlation coefficients ranging from 0.44 to 0.80. Unexpectedly the NAME run using radar rainfall data had a lower correlation coefficient (R = 0.66), when compared to observations, than the run using the JMA mesoscale model rainfall (R = 0.76) or the run using ECMWF met data (R = 0.80). Additionally the impact of modifying the wet scavenging coefficients used in the parameterisation of wet deposition was investigated. The results showed that modifying the scavenging parameters had a similar impact to modifying the driving meteorology on the rank calculated from comparing the modelled and observed deposition.

  13. 铯原子喷泉钟均匀C场的实现%A realization of uniform C field in caesium atomic fountain clock

    Institute of Scientific and Technical Information of China (English)

    吴长江; 管勇; 陈江; 张辉; 阮军; 张首刚

    2011-01-01

    C场均匀度是影响铯原子喷泉钟性能的重要因素。为了消除漏磁等对磁场均匀度的影响,加入补偿线圈,通过用最小二乘法计算,逐次得出补偿线圈的个数、位置与电流。实验表明:计算数据与实验结果吻合,得到c场不均匀性小于2nT、长度达48cm的均匀区。%The performance of the caesium atomic fountain clock is affected by the uniformity of the C field. In order to compensate the uneven magnetic field caused by the leakage in magnetic shielding region, compensation coils are introduced and the number, position and current of the coils are calculated by the least square methgd. The experimental results agree with the theoretical prediction and an uniform magnetic-field of 48 cm with a fluctuation of less than 2 nT is obtained.

  14. Relationship between caesium (137Cs) load, cardiovascular symptoms, and source of food in 'Chernobyl' children -- preliminary observations after intake of oral apple pectin.

    Science.gov (United States)

    Bandazhevskaya, G S; Nesterenko, V B; Babenko, V I; Yerkovich, T V; Bandazhevsky, Y I

    2004-12-18

    Seventeen years after the nuclear power accident at Chernobyl, most of the radio-contamination among the population of Southern Belarus is caused by incorporation of long-lived radioisotopes. The varying levels of 137Cs observed among children in this area are explained by the source of their food, especially by the consumption of contaminated milk produced privately. We stratified children from rural areas of Belarus (caesium [137Cs] contamination >5 Ci/km(2)) by their 137Cs loads into three distinct groups (group 1, <5 Bq/kg body weight [BW]; group 2, 38.4 +/- 2.4 Bq/kg BW; group 3, 122 +/- 18.5 Bq/kg BW). We determined the relationship between the 137Cs load and the children's main source of food and recorded their cardiovascular symptoms. Cardiovascular symptoms, ECG alterations, and arterial hypertension were significantly more frequent in children with high 137Cs burden than in children with very low 137Cs burden. Children with moderate and high 137Cs loads (groups 2 and 3) received apple pectin, a food additive, for 16 days. Apple pectin significantly decreased 137Cs loads in these groups (39% and 28%, respectively). ECG alterations improved, while cardiovascular symptoms and hypertension did not change in any group.

  15. Crystal structure of 5-butylamino-3-methyl-1-(pyridin-2-yl-1H-pyrazole-4-carbaldehyde obtained from a microwave-assisted reaction using caesium carbonate as catalyst

    Directory of Open Access Journals (Sweden)

    Mario A. Macías

    2016-11-01

    Full Text Available The title compound, C14H18N4O, synthesized from an unconventional microwave-assisted method using caesium carbonate as catalyst, has an approximately planar conformation with the pyridyl and pyrazole rings inclined by a dihedral angle of 7.94 (3°, allowing the formation of an intramolecular N—H...N hydrogen bond. The supramolecular assembly has a three-dimensional arrangement controlled mainly by weak C—H...O and C—H...π interactions.

  16. Combining caesium-137 measurements and suspended sediment load data to investigate the sediment response of a small catchment in southern Italy

    Science.gov (United States)

    Porto, P.; Walling, D. E.; La Spada, C.; Mallimo, N.

    2015-03-01

    A long-term measurement programme was operated in southern Italy during the 1960s and 1970s, to provide information on the suspended sediment yields from the main river basins. Information obtained for the rivers of Calabria suggests that suspended sediment yields in this area are relatively low. However, there is evidence that the intensity of land degradation within the upstream catchments is substantially higher than suggested by the values of specific sediment yield and there is a need to explore the relationship between on-site soil loss and downstream sediment yield more closely. Monitoring time-integrated erosion rates over large areas has traditionally required extensive long-term measurement programmes employing experimental plots. The fallout radionuclide caesium-137 (137Cs) offers an alternative means of documenting medium-term rates of soil loss. This paper describes the use of 137Cs measurements and the available sediment load data to explore the links between soil erosion, sediment redistribution and storage, and sediment output for a medium-scale (41.3 km2) catchment in Calabria. Data available from a sediment load monitoring programme undertaken at the catchment outlet during 1962-1977 have been used to estimate the longer-term catchment sediment yield. This estimate has been combined with information provided by the 137Cs measurements, to establish a medium-term sediment budget for the catchment. The results provided by the 137Cs measurements indicate that the catchment is subject to much higher rates of soil loss and land degradation than suggested by its specific sediment yield. These findings are consistent with the results obtained for other catchments in Calabria for which both 137Cs derived erosion rates and measured sediment yields are available.

  17. Some thoughts on the compliance with intervention levels in an area contaminated by an accidental deposition of caesium 137; Reflexions sur le respect des niveaux d`intervention dans un territoire contamine par un depot accidentel de cesium 137

    Energy Technology Data Exchange (ETDEWEB)

    Maubert, H.; Robeau, D.; Renaud, P. [CEA Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France); Linge, I.; Pavlovski, O.; Ossipiants, I. [Institut de Surete Nucleaire, Moscou (Russian Federation)

    1995-10-01

    After a nuclear accident leading to an important radionuclide deposition, the responsible authorities are faced to the question of complying with intervention levels. These regulations may be expressed as mass activities in foodstuffs, or individual doses for the populations. A situation of acute caesium 137 contamination of the environment was played in 1993 during a French and Russian joint crisis exercise. In answering the questions from the administration, the experts examined the conditions allowing agricultural practices (1) according to a set of intervention levels in foodstuffs, and (2) how that was compatible with a recommendation relative to an individual dose for the populations of 1 mSv/y, although this limit is applicable in normal conditions and is not intended for post-accidental situations. (authors). 9 refs., 2 figs., 3 tabs.

  18. Fe(III) in a low-spin state in caesium bis[3-ethoxysalicylaldehyde 4-methylthiosemicarbazonato(2-)-κ3O2,N1,S]ferrate(III) methanol monosolvate.

    Science.gov (United States)

    Powell, Robyn E; Schwalbe, Carl H; Tizzard, Graham J; Koningsbruggen, Petra J van

    2014-06-01

    The synthesis and crystal structure (at 100 K) of the title compound, Cs[Fe(C11H13N3O2S2)2]·CH3OH, is reported. The asymmetric unit consists of an octahedral [Fe(III)(L)2](-) fragment, where L(2-) is 3-ethoxysalicylaldehyde 4-methylthiosemicarbazonate(2-) {systematic name: [2-(3-ethoxy-2-oxidobenzylidene)hydrazin-1-ylidene](methylamino)methanethiolate}, a caesium cation and a methanol solvent molecule. Each L(2-) ligand binds through the thiolate S, the imine N and the phenolate O atoms as donors, resulting in an Fe(III)S2N2O2 chromophore. The O,N,S-coordinating ligands are orientated in two perpendicular planes, with the O and S atoms in cis positions and the N atoms in trans positions. The Fe(III) cation is in the low-spin state at 100 K.

  19. Study on Adsorption Performance of Zeolite from Xinjiang Province for Radioactive Strontium and Caesium%新疆沸石对放射性核素锶和铯的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    王哲; 李海峰

    2015-01-01

    The static adsorption experiments are carried out to investigate the adsorption performance of strontium and caesium on zeolite in different adsorption time,pH values,adsorbent dosage and initial con-centration.These results indicates that the adsorption performance of zeolite for Cs+is better than Sr2+, and the reason is that hydrated ionic radius of caesium is bigger than hydrated ionic radius of strontium, so that Cs+is more easily to be adsorbed into the interlayer of zeolite than Sr2+, when Sr2+and Cs+are respectively exchanged with Na+、K+、Ca2+and Mg2+of zeolite.%采用静态吸附实验方法,研究了吸附时间、溶液pH值、吸附剂投加量和溶液初始浓度等因素对新疆沸石吸附Sr2+和Cs+的性能的影响。结果表明:新疆沸石对含Cs+放射性废水的处理效果要优于对含Sr2+的处理效果,其原因在于Cs+离子水合半径比Sr2+的离子水合离子小,当Sr2+和Cs+与沸石层间Na+、K+、Ca2+和Mg2+等发生离子交换时,Cs+离比Sr2+离子更易于进入蒙脱石层间而被固定。

  20. Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2011-10-01

    Full Text Available On 11 March 2011, an earthquake occurred about 130 km off the Pacific coast of Japan's main island Honshu, followed by a large tsunami. The resulting loss of electric power at the Fukushima Dai-ichi nuclear power plant (FD-NPP developed into a disaster causing massive release of radioactivity into the atmosphere. In this study, we determine the emissions of two isotopes, the noble gas xenon-133 (133Xe and the aerosol-bound caesium-137 (137Cs, which have very different release characteristics as well as behavior in the atmosphere. To determine radionuclide emissions as a function of height and time until 20 April, we made a first guess of release rates based on fuel inventories and documented accident events at the site. This first guess was subsequently improved by inverse modeling, which combined the first guess with the results of an atmospheric transport model, FLEXPART, and measurement data from several dozen stations in Japan, North America and other regions. We used both atmospheric activity concentration measurements as well as, for 137Cs, measurements of bulk deposition. Regarding 133Xe, we find a total release of 16.7 (uncertainty range 13.4–20.0 EBq, which is the largest radioactive noble gas release in history not associated with nuclear bomb testing. There is strong evidence that the first strong 133Xe release started very early, possibly immediately after the earthquake and the emergency shutdown on 11 March at 06:00 UTC. The entire noble gas inventory of reactor units 1–3 was set free into the atmosphere between 11 and 15 March 2011. For 137Cs, the inversion results give a total emission of 35.8 (23.3–50.1 PBq, or about 42% of the estimated Chernobyl emission. Our results indicate that 137Cs emissions peaked on 14–15 March but were generally high from 12 until 19 March, when they suddenly dropped by orders of magnitude exactly when spraying of

  1. Transport behavior of radioactive caesium from forests contaminated by the Fukushima Dai-ichi nuclear power plant accident through river water system

    Energy Technology Data Exchange (ETDEWEB)

    Iijima, K.; Funaki, H.; Ohyama, T.; Niizato, T.; Sato, H.; Yui, M. [Japan Atomic Energy Agency (Japan)

    2014-07-01

    Japan Atomic Energy Agency (JAEA) has carried out 'the project on the Long-term Assessment of Transport of Radioactive Contaminant in the Environment of Fukushima (F-TRACE project)' since the end of 2012. Radioactive caesium (Cs) has been distributed by the fallout by the Fukushima Dai-ichi Nuclear Power Plant (1F-NPP) accident, and forests in mountain areas have large amount of inventory of radioactive Cs and cover relatively large part of contaminated area of Fukushima. In this project, the transport behavior of radioactive Cs from the forests to biosphere and sea is evaluated by computer simulation based on the results of field observation and laboratory experiments. The results are used to predict evolution of effective dose of the residents in the affected area due to the transport, specify the dominant pathway of Cs, and propose effective methodology to constrain the transport along the pathway. This study reports the specific transport behavior of Cs observed in the basins of five rivers by means of the field investigation and laboratory experiments during the first year of the project. Radioactive Cs located at the crown was considered to be transported to the soil surface by litter fall, stem flow and canopy drip in the Japanese cedar tree forests. Even after two years since the accident, more than 90% of radioactive Cs was still been remained within 5 cm depth from the top of the soil, indicating that the distribution coefficient of radioactive Cs onto the specific minerals such as clay was significantly high. In the river, relatively higher dose rate was observed at the flood channel where fine-grained soil particles were trapped by growing vegetation, while low dose rate was observed beside the river channel where coarse sand or gravel accumulated. The results suggested that fine-grained soil particles containing minerals adsorbing large amount of radioactive Cs were transported in high water level and trapped by the vegetation. In the dam

  2. Atmospheric lifetime of caesium-137 as an estimate of aerosol lifetime -quantified from global measurements in the months after the Fukushima Dai-ichi nuclear accident

    Science.gov (United States)

    Iren Kristiansen, Nina; Stohl, Andreas; Wotawa, Gerhard

    2013-04-01

    Radionuclides like caesium-137 (137Cs) can be emitted to the atmosphere in great quantities during nuclear accidents and are of significant health impact. A global set of radionuclide measurements collected over several months after the accidental release from the Fukushima Dai-ichi nuclear power plant in March 2011 has been used to estimate the atmospheric lifetime of 137Cs. Lifetime is here defined as the e-folding time scale (the time interval in which the exponential decay of the 137Cs quantity has decreased by factor of e). The estimated atmospheric lifetime of 137Cs can also be used as an estimate of the lifetime of aerosols in the atmosphere. This is based on the fact that 137Cs attaches to the ambient accumulation-mode (AM) aerosols and trace their fate in the atmosphere. The 137Cs "tags" the AM aerosols and both the 137Cs and AM aerosols are removed simultaneously from the atmosphere by scavenging within clouds, precipitation and dry deposition. The 137Cs emitted from Fukushima attached mainly to sulphate aerosols in the size range 0.1-2 μm diameter. Measured 137Cs activity concentrations from several stations spread mostly over the Northern Hemisphere were evaluated, and the decrease in activity concentrations over time (after correction for radioactive decay) reflects the removal of aerosols by wet and dry deposition. Corrections for air mass transport were made using measurements of the noble gas xenon-133 (133Xe) which was also released during the accident. This noble gas does not attach to the aerosols and was thus used as a passive tracer of air mass transport. The atmospheric lifetime of 137Cs was estimated to 10.0-13.9 days during April and May 2011. This represents the atmospheric lifetime of a "background" AM aerosol well mixed in the extratropical northern hemisphere troposphere. It is expected that the lifetime of this vertically mixed background aerosol is longer than the lifetime of fresh AM aerosols directly emitted from surface sources

  3. Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2012-03-01

    Full Text Available On 11 March 2011, an earthquake occurred about 130 km off the Pacific coast of Japan's main island Honshu, followed by a large tsunami. The resulting loss of electric power at the Fukushima Dai-ichi nuclear power plant developed into a disaster causing massive release of radioactivity into the atmosphere. In this study, we determine the emissions into the atmosphere of two isotopes, the noble gas xenon-133 (133Xe and the aerosol-bound caesium-137 (137Cs, which have very different release characteristics as well as behavior in the atmosphere. To determine radionuclide emissions as a function of height and time until 20 April, we made a first guess of release rates based on fuel inventories and documented accident events at the site. This first guess was subsequently improved by inverse modeling, which combined it with the results of an atmospheric transport model, FLEXPART, and measurement data from several dozen stations in Japan, North America and other regions. We used both atmospheric activity concentration measurements as well as, for 137Cs, measurements of bulk deposition. Regarding 133Xe, we find a total release of 15.3 (uncertainty range 12.2–18.3 EBq, which is more than twice as high as the total release from Chernobyl and likely the largest radioactive noble gas release in history. The entire noble gas inventory of reactor units 1–3 was set free into the atmosphere between 11 and 15 March 2011. In fact, our release estimate is higher than the entire estimated 133Xe inventory of the Fukushima Dai-ichi nuclear power plant, which we explain with the decay of iodine-133 (half-life of 20.8 h into 133Xe. There is strong evidence that the 133Xe release started before the first active venting was made, possibly indicating structural damage to reactor components and/or leaks due to overpressure which would have allowed early release of noble gases. For 137

  4. Strontium and caesium transport in unsaturated soil from Chernobyl Pilot Site under steady flow conditions; Transfert de radioelements en zone non saturee. Etude experimentale et modelisation appliquees au Site Pilote de Tchernobyl

    Energy Technology Data Exchange (ETDEWEB)

    Szenknect, St

    2003-10-15

    This work is devoted to the quantification and the identification of the predominant processes involved in strontium and caesium transport in unsaturated soil from Chernobyl Pilot Site under steady flow conditions. The transport and fate of radionuclides in the subsurface is affected by various physical and chemical processes including advective and diffusive transport as well as chemical and biological transformations. Laboratory experiments and the use of a multiple tracer approach allow to isolate the contributions of each elementary process and to control the physico-chemical conditions in the system. To be more representative of the field conditions, we decided to perform column miscible displacement experiments. We perform batch and flow-through reactor experiments to characterize the radionuclides sorption mechanisms. Miscible displacement experiments within homogeneous columns and modeling allow to characterize the hydrodynamic properties of the soil and to describe the radionuclides behaviour under dynamic conditions at different water contents. We show that the water content of porous media affect the transport behaviour of inert and strongly sorbing radionuclides. Our results demonstrate that a parametrized transport model that was calibrated under completely saturated conditions was not able to describe the advective-dispersive transport of reactive solutes under unsaturated steady state conditions. Under our experimental conditions, there is no effect of a decrease of the mean water content on the sorption model parameters, but the transport parameters are modified. We established for the studied soil the relation between hydrodynamic dispersion and water content and the relation between pore water velocity and water content. (author)

  5. European inter-comparison of Monte Carlo codes users for the uncertainty calculation of the kerma in air beside a caesium-137 source; Intercomparaison europeenne d'utilisateurs de codes monte carlo pour le calcul d'incertitudes sur le kerma dans l'air aupres d'une source de cesium-137

    Energy Technology Data Exchange (ETDEWEB)

    De Carlan, L.; Bordy, J.M.; Gouriou, J. [CEA Saclay, LIST, Laboratoire National Henri Becquerel, Laboratoire de Metrologie de la Dose 91 - Gif-sur-Yvette (France)

    2010-07-01

    Within the frame of the CONRAD European project (Coordination Network for Radiation Dosimetry), and more precisely within a work group paying attention to uncertainty assessment in computational dosimetry and aiming at comparing different approaches, the authors report the simulation of an irradiator containing a caesium 137 source to calculate the kerma in air as well as its uncertainty due to different parameters. They present the problem geometry, recall the studied issues (kerma uncertainty, influence of capsule source, influence of the collimator, influence of the air volume surrounding the source). They indicate the codes which have been used (MNCP, Fluka, Penelope, etc.) and discuss the obtained results for the first issue

  6. Potassium, rubidium and caesium in fungi

    Energy Technology Data Exchange (ETDEWEB)

    Johanson, K.J.; Nikolova, I. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology; Vinichuk, M. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences

    2005-09-15

    Samples of mushrooms and soil were collected in a forest ecosystem close to Nuclear Power Plant at Forsmark, Sweden. The soil were fractionated in bulk soil, rhizosphere, soil-root interface and fungal mycelium and the concentration of K, Rb and Cs were determined. The K concentration increased from 605 mg/kg in bulk soil to 2,750 mg/kg in mycelium and 39,500 in fruitbodies of fungi. The corresponding values for Rb was 2.5 mg/kg in bulk soil and 191 mg/kg in fruitbodies of fungi. For Cs the corresponding values were 0.21 mg/kg for bulk soil and 3.9 mg/kg in fruitbodies. In fruitbodies of fungi good correlation was found between the concentration of K and Rb or of Rb and Cs, but not between K and Cs. Yoshida found similar correlation and concluded that the mechanism of Cs uptake by fungi may be different from that of K.

  7. Twinned caesium cerium(IV pentafluoride

    Directory of Open Access Journals (Sweden)

    Andrzej Grzechnik

    2014-03-01

    Full Text Available Single-crystals of CsCeF5 were synthesized hydrothermally. The crystal under investigation was twinned by pseudo-merohedry with a twofold rotation around the c axis as an additional twinning operation. The crystal structure is built of layers of distorted edge- and corner-sharing CeF8 square-antiprisms. The Cs+ cations are located between the layers and exhibit coordination numbers of nine. Upon compression, CsCeF5 undergoes an irreversible phase transition at about 1 GPa.

  8. The mechanism of caesium intercalation of graphene.

    Science.gov (United States)

    Petrović, M; Šrut Rakić, I; Runte, S; Busse, C; Sadowski, J T; Lazić, P; Pletikosić, I; Pan, Z-H; Milun, M; Pervan, P; Atodiresei, N; Brako, R; Šokčević, D; Valla, T; Michely, T; Kralj, M

    2013-01-01

    Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene, can be manipulated by the inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers; however, the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also have a role for intercalation of layered materials.

  9. Marine dispersion of caesium 137 released from Sellafield and Chernobyl

    Science.gov (United States)

    Prandle, D.; Beechey, J.

    1991-09-01

    This modelling study examines the dispersion within the shelf seas surrounding the UK, of 137Cs discharged from Sellafield between 1969 and 1988 together with the atmospheric deposition following Chernobyl (April 1986). The close agreement obtained between computed and observed distributions lends confidence to estimates of flushing times-fundamental parameters in determining pollutant concentrations. Moreover, this study confirms, to first-order, the estimates of Chernobyl fall-out provided by atmospheric dispersion models.

  10. Parameters for Cold Collisions of Lithium and Caesium Atoms

    CERN Document Server

    Ouerdane, H

    2015-01-01

    We calculate the s-wave scattering length and effective range and the p-wave scattering volume for $^7$Li atoms interacting with $^{133}$Cs atoms via the X$^1\\Sigma^+_g$ molecular potential. The length and volume are found by fitting the log-derivative of the zero energy wave function evaluated at short range to a long range expression that accounts for the leading van der Waals dispersion potential and then incorporating the remaining long range dispersion contributions to first order. The effective range is evaluated from a quadrature formula. The calculated parameters are checked from the zero energy limits of the scattering phase shifts. We comment on ill-conditioning in the calculated s-wave scattering length.

  11. Parameters for Cold Collisions of Lithium and Caesium Atoms

    Institute of Scientific and Technical Information of China (English)

    Jamieson M. J.; Ouerdane H.

    2011-01-01

    @@ We calculate the s-wave scattering length and effective range and the p-wave scattering volume for Li atoms interacting with 133CS atoms via the X∑ molecular potential.The length and volume are found by fitting the log-derivative of the zero energy wave function evaluated at short range to a long range expression that accounts for the leading van der Waals dispersion potential and then incorporating the remaining long range dispersion contributions to first order.The effective range is evaluated from a quadrature formula.The calculated parameters are checked from the zero energy limits of the scattering phase shifts.We comment on ill-conditioning in the calculated s-wave scattering length.%We calculate the s-wave scattering length and effective range and the p-wave scattering volume for 7Li atoms interacting with 133Cs atoms via the X1E+ molecular potential. The length and volume are found by fitting the log-derivative of the zero energy wave function evaluated at short range to a long range expression that accounts for the leading van der Waals dispersion potential and then incorporating the remaining long range dispersion contributions to first order. The effective range is evaluated from a quadrature formula. The calculated parameters are checked from the zero energy limits of the scattering phase shifts. We comment on ill-conditioning in the calculated s-wave scattering length.

  12. Animated molecular dynamics simulations of hydrated caesium-smectite interlayers

    Directory of Open Access Journals (Sweden)

    Sposito Garrison

    2002-09-01

    Full Text Available Computer animation of center of mass coordinates obtained from 800 ps molecular dynamics simulations of Cs-smectite hydrates (1/3 and 2/3 water monolayers provided information concerning the structure and dynamics of the interlayer region that could not be obtained through traditional simulation analysis methods. Cs+ formed inner sphere complexes with the mineral surface, and could be seen to jump from one attracting location near a layer charge site to the next, while water molecules were observed to migrate from the hydration shell of one ion to that of another. Neighboring ions maintained a partial hydration shell by sharing water molecules, such that a single water molecule hydrated two ions simultaneously for hundreds of picoseconds. Cs-montmorillonite hydrates featured the largest extent of this sharing interaction, because interlayer ions were able to inhabit positions near surface cavities as well as at their edges, close to oxygen triads. The greater positional freedom of Cs+ within the montmorillonite interlayer, a result of structural hydroxyl orientation and low tetrahedral charge, promoted the optimization of distances between cations and water molecules required for water sharing. Preference of Cs+ for locations near oxygen triads was observed within interlayer beidellite and hectorite. Water molecules also could be seen to interact directly with the mineral surface, entering its surface cavities to approach attracting charge sites and structural hydroxyls. With increasing water content, water molecules exhibited increased frequency and duration of both cavity habitation and water sharing interactions. Competition between Cs+ and water molecules for surface sites was evident. These important cooperative and competitive features of interlayer molecular behavior were uniquely revealed by animation of an otherwise highly complex simulation output.

  13. 铯盐应用及铯(碱金属)矿产资源评价%CAESIUM APPICATION AND CAESIUM(ALKALI METALS) RESOURCE EVALUATION

    Institute of Scientific and Technical Information of China (English)

    董普; 肖荣阁

    2005-01-01

    铯是稀有轻碱金属,在现代高科技领域具有广泛的应用前景,本文重点分析了我国铯矿资源类型及其主要分布.铯是碱金属元素,因此主要产于碱性岩中或盐湖中,与碱金属锂、铷,稀有金属铌、钽及稀土等共生或伴生.我国的主要铯矿矿床类型可以划分五种产出类型,即碱性花岗伟晶岩中的铯榴石矿床;铌钽矿床中伴生铯矿;风化沉积型铯铌矿;含铯锂卤水:以及现代地热区域的含铯硅质岩.

  14. Gamma spectrometry inspection of TRIGA MARK II fuel using caesium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Karimzadeh, S., E-mail: sam.karimzadeh@ati.ac.a [Vienna University of Technology, Institute of Atomic and Subatomic Physics (ATI), Stadionallee 2, A-1020 Vienna (Austria); Khan, R.; Boeck, H. [Vienna University of Technology, Institute of Atomic and Subatomic Physics (ATI), Stadionallee 2, A-1020 Vienna (Austria)

    2011-01-15

    Research highlights: Cs isotopes are the best choices for the burn up determination of spent fuel. Gamma spectrometer calibration using MCNP5. Cs-ratio can be applied by relative calibration method. - Abstract: Gamma spectrometry is one of the common methods to inspect the spent fuel from research reactors. This method has been applied to in-pool measurements of the Spent Fuel Elements (SPEs) of the TRIGA Mark II research reactor. Due to mixed nature of the reactor core and complicated irradiation history of the fuel elements (FEs), the gamma spectrometry of the FE establishes improvements in the calculation and measurement of the SPE. In order to inspect the TRIGA SPE from dry storage and cooled fuel from the reactor pool, the selected spend fuels are scanned and measured using the fuel-scanning machine. Gamma spectrometry is performed by HPGe detector for spend fuel inspection and determination of the {sup 137}Cs activity and {sup 134}Cs/{sup 137}Cs ratio. In this work, the steps of the detector calibration and the use of the Monte Carlo radiation transport code (MCNP5) have been described. In addition, the fuel-scanning machine and the gamma spectrometer are modelled by MCNP5 to simulate the gamma transport from fuel to detector. It also simulate the gamma spectrometer calibration for the burn up determination of the spend fuel. The results from MCNP5 simulation are applied to spectroscopic measurements and compared with the theoretical predictions of the neutronics code ORIGEN2 in this research work.

  15. A comparison of stable caesium uptake by six grass species of contrasting growth strategy

    Energy Technology Data Exchange (ETDEWEB)

    Willey, N.J. [University of the West of England, Bristol (United Kingdom). Faculty of Applied Sciences; Martin, M.H. [Bristol Univ. (United Kingdom). School of Biological Sciences

    1997-05-14

    Six plants in the family Gramineae were used to investigate the relationship between Cs uptake, nutrient regime and plant growth strategy sensu Grime (1979: Plant Growth Strategies and Vegetation Processes, John Wiley). The roots of 66 day old Elymus repens (L.) Gould., Bromus sterilis L., Agrostis stolonifera L., Anthoxanthum odoratum L., Festuca ovina L. and Nardus stricta L. plants grown in acid-washed sand at high and low nutrient levels were exposed to a 96 h pulse of stable Cs at 0.05 mM, 0.15 mM, 0.3 mM, 1.0 mM and 3.0 mM concentrations. Different nutrient regimes induced large differences in dry wt in E. repens, B. sterilis and A. stolonifera plants but only small differences in N. stricta and F. ovina plants. At high nutrient concentrations, A. stolonifera, A. odoratum, F. ovina and N. stricta shoots showed significantly greater increases in internal Cs concentration with rising external Cs concentrations than did E. repens and B. sterilis shoots. The relationship between increases in shoot and external Cs concentrations was statistically indistinguishable between species in plants grown at the low nutrient concentration. These patterns of Cs uptake ensured that with long-term high K concentrations the more competitive plants (E. repens and B. sterilis) accumulated higher concentrations of Cs from low external concentrations than did non-competitive plants or competitive plants grown at low nutrient levels. It is suggested that the relationship between plant growth strategy sensu Grime (1979) and Cs accumulation patterns may help to explain the different concentrations to which species accumulate radiocaesium from the soil. (author).

  16. A comparison of stable caesium uptake by six grass species of contrasting growth strategy.

    Science.gov (United States)

    Willey, N J; Martin, M H

    1997-01-01

    Six plant species in the family Gramineae were used to investigate the relationship between Cs uptake, nutrient regime and plant growth strategy sensu Grime (1979: Plant Growth Strategies and Vegetation Processes, John Wiley). The roots of 66 day old Elymus repens (L.) Gould., Bromus sterilis L., Agrostis stolonifera L., Anthoxanthum odoratum L., Festuca ovina L. and Nardus stricta L. plants grown in acid-washed sand at high and low nutrient levels were exposed to a 96 h pulse of stable Cs at 0.05 mM, 0.15 mM, 0.3 mM, 1.0 mM and 3.0 mM concentrations. Different nutrient regimes induced large differences in dry wt in E. repens, B. sterilis and A. stolonifera plants but only small differences in N. stricta and F. ovina plants. At high nutrient concentrations, A. stolonifera, A. odoratum, F. ovina and N. stricta shoots showed significantly greater increases in internal Cs concentration with rising external Cs concentrations than did E. repens and B. sterilis shoots. The relationship between increases in shoot and external Cs concentrations was statistically indistinguishable between species in plants grown at the low nutrient concentration. These patterns of Cs uptake ensured that with long-term high K concentrations the more competitive plants (E. repens and B. sterilis) accumulated higher concentrations of Cs from low external concentrations than did non-competitive plants or competitive plants grown at low nutrient levels. It is suggested that the relationship between plant growth strategy sensu Grime (1979) and Cs accumulation patterns may help to explain the different concentrations to which species accumulate radiocaesium from the soil.

  17. Spatial distribution of caesium-137 in soil cover of background terrestrial ecosystems, Central European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Paramonova, Tatiana A. [Radioecology and Ecotoxicology Department of Soil Science Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation); Shamshurina, Evgenia N. [Laboratory of soil erosion and fluvial processes of Geography Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation)

    2014-07-01

    ¹³⁷Cs - the main long-living anthropogenic radionuclide - arrived in mass at Russian terrestrial ecosystems after nuclear tests in the atmosphere in 1960-yy. and after Chernobyl accident in 1986 y., but in spite of a long period since these events soil cover contamination by ¹³⁷Cs is considered as extremely resistant due to its firmly fixation by soil solid matter and a long half-life of the radionuclide. Wide-scale investigation in maximal diversity of natural, semi-natural and anthropogenic landscapes of Central European Russia (more than 400 soils samples from Vologda, Yaroslavl, Ivanovo, Tver regions which are representative for the southern taiga zone) demonstrates that modern average specific activity of ¹³⁷Cs in the upper 15-cm layer of soil is 11±3 Bq/kg (contamination density 0.05±0.01 Ci/km²), that is fully ecologically acceptable. It is important that the average concentrations of ¹³⁷Cs in the soil cover of individual regions are close to each other. The most likely these average values are approximate assessment of background radioactive contamination of soils in central European Russia outside of the immediate Chernobyl trace. At the same time approximately 3% of soils are characterized by elevated ¹³⁷Cs content - 62-98 Bq/kg (0.24-0.43 Ci/km²), that indicates the presence of low radioactive spots on the territory and may be considered as local Chernobyl fallout. All of them attribute with forest soils which are commonly characterized by considerably more high accumulation of ¹³⁷Cs (18±5 Bq/kg, 0.06±0.01 Ci/km²) due to advanced absorbing surface of trees. Agricultural lands (plagued or under meadows) and soils of industrial plots with scarce vegetation contain only 6±2 Bq/kg (0.03±0.01 Ci/km²) of ¹³⁷Cs. About 84-92% of ¹³⁷Cs are concentrated in the upper 15-cm layer of natural soils or in Ap horizon of plagued soils, thus vertical migration of radionuclide is very slow in spite of ~30 years after Chernobyl accident. But it may by considerable lateral migration of ¹³⁷Cs in geochemically connected landscapes through the process of water erosion that leads to additional radionuclide accumulation in peat and foggy-podsolic soils of watershed depressions (migration coefficient 1.3). Thus, shallow depressions could be those 'critical' elements of the landscape with low-contrast areas of additional ¹³⁷Cs accumulation. Long-range transport of ¹³⁷Cs in moderate humid landscapes seems of little importance since alluvial soils and bottom sediments contain only 8±4 Bq/kg and 2±1 Bq/kg correspondingly. (authors)

  18. Structure of liquid caesium-bismuth alloys studied by neutron diffraction

    NARCIS (Netherlands)

    van der Aart, SA; Verhoeven, VWJ; Verkerk, P; van der Lugt, W

    2000-01-01

    Neutron diffraction experiments were carried out for two liquid alloys with compositions CsBi and Cs3Bi2. The results indicate that probably polyanions with an average number of about two Bi atoms per cluster are formed. This result contrasts with that for liquid Cs-Sb, which contains larger chains

  19. The use of caesium-137 to estimate agricultural erosion on steep slopes in a tropical watershed

    Science.gov (United States)

    Nagle, Gregory N.; Lassoie, James P.; Fahey, Timothy J.; McIntyre, Sherwood C.

    2000-04-01

    The estimation of erosion and sediment delivery rates in tropical mountain watersheds is difficult and most of the methods widely used for estimating soil erosion over large areas have serious limitations. The 137Cs approach has potential for quantifying soil erosion because it can provide retrospective estimates of long-term (since 1963) net sediment redistribution relatively quickly. Despite its great potential, 137Cs has not yet been used in an extensive, reconnaissance level survey of erosion in complex tropical mountain environments. The objective of this study was to examine the applicability of the 137Cs method to estimate erosion on steep tropical agricultural lands (23 to 80% slopes) in the Nizao watershed, a humid, tropical mountain area of the Dominican Republic. In this study we (i) examine the variation of 137Cs in ten reference sites - eight coffee groves and two forested sites - and (ii) estimate erosion from 14 cultivated fields.The soil pool of 137Cs ranged from to 150 to 192 mBq cm-2 on reference sites with minimal erosion. Variability among reference sites was less than expected for such complex mountain terrain. The variability within coffee and forested reference (average CV=28%) sites was similar to the variability found on grassland and forested reference sites in the temperate zone.The estimated annual soil loss from 14 sampled fields ranged from 6 to 61 t ha-1 year-1 with an overall mean of 26 t ha-1 year-1. Overall, the soil erosion estimates found using the

  20. Caesium-137 in sediments from two Norwegian fjords- Including dating sediment cores

    OpenAIRE

    Sværen, Ingrid

    2010-01-01

    Summary The fission product Cs-137 is present in all parts of the Norwegian environment, brought here atmospherically or by ocean currents. The most important sources are fallout from atmospheric nuclear weapons tests, discharges from nuclear fuel repossessing plants and fallout from the Chernobyl accident which have caused the presence of this radionuclide in the marine environment. The environmental presence of this radionuclide is thoroughly monitored, and the content in the Norwegian m...

  1. Speciation of caesium-137 and plutonium-isotopes in Chernobyl soil

    OpenAIRE

    Holmstrand, Marte Varpen

    2011-01-01

    The Chernobyl Nuclear Power Plant (ChNPP) accident (1986) in present day Ukraine, was the first INES level 7 nuclear accident in the history of nuclear power. About 6-8 tonnes of spend uranium fuel were released and the fallout contained a series of short- and long lived radionuclides. The main deposition was in an area 30 km around the ChNPP, and the southern parts of Belarus. The area was permanently evacuated and called the exclusion zone. Some of the most long lived radionuclides released...

  2. Uptake of caesium-137 from peat and compost mould by vegetables in a greenhouse experiment

    Energy Technology Data Exchange (ETDEWEB)

    Malm, J.; Uusi-Rauva, A.; Paakkola, O. (Helsinki Univ. (Finland). Faculty of Agriculture and Forestry); Rantavaara, A. (Finnish Centre for Radiation and Nuclear Safety (STUK), Helsinki (Finland))

    1991-01-01

    A pot experiment was conducted to study the root uptake of {sup 137} Cs by vegetables grown in peat and composite mould in a greenhouse. The {sup 137}Cs in the growing media originated from Chernobyl fallout. The vegetables were cucumber (Cucumis sativus L. var. Farbio VDP SF 76), tomato (Lycopersicon esculentum L. Var. Virosa), parsley (Petroselinum crispum A.W. Hill var. Non plus ultra), radish (Raphanus Sativus L. var. Nondan) and lettuce (Lactuca sativa L. var Atraktion). The effect of adding potassium to the peat was also studied. The transfer factors (activity in plant dry weight/activity in soil dry weight) varied from 0.66 to 1.8 for peat and from 0.060 to 0.19 for compost mould. Addition of potassium did not have any clear effect on the transfer factors. (Author).

  3. Does the Fukushima NPP disaster affect the caesium activity of North Atlantic Ocean fish?

    Directory of Open Access Journals (Sweden)

    G. Kanisch

    2013-08-01

    Full Text Available Fillet samples of marine fish collected from the East/West Greenland currents (GC and from the Baltic Sea (BS have been investigated by gamma-ray spectrometry within the regular German monitoring programme. In samples of the second half of 2011, 134Cs traces have been detected that are suggested to originate from the Fukushima fallout that was deposited in March/April 2011 over the northern North Atlantic and accumulated by fish. The radionuclide 134Cs (half-life 2 yr was indeed detected with quite small activities at about 0.0036 Bq kg−1 w.w. Existing box models describing the transport of Cs within seawater boxes of the northeast Atlantic allowed for estimation of 134Cs contributions from other sources, i.e. from the Chernobyl fallout and from discharges by the two major European nuclear reprocessing plants; both were negligible around Greenland, while for the Chernobyl fallout a small 134Cs background contribution to BS fish was estimated. Model results confirmed the level of 134C measured in BS fish and showed its maximum to have occurred in winter 2011/2012 followed by a continuous decrease. It was also determined that 134Cs activity, but not that of 134Cs, showed a significant negative correlation with sampling depth (150–400 m of GC fish; this strengthens our Fukushima fallout assumption. As a result, the Fukushima fallout in these sea areas only marginally enhanced (GC: 4%; BS: 0.1% pre-Fukushima levels of individual dose rates received by human fish consumers; the addition was around 0.001 μSv following the consumption of 10 kg of fish per year, which is not expected to cause concern according to present guidelines for radiation protection.

  4. Inter-varietal variation in caesium and strontium uptake by plants: a meta-analysis.

    Science.gov (United States)

    Penrose, B; Beresford, N A; Broadley, M R; Crout, N M J

    2015-01-01

    Radiocaesium and radiostrontium enter the foodchain primarily via plant root uptake. Selecting varieties of crop that display low accumulation of these radionuclides has been suggested as an economically and socially acceptable remediation strategy for radiologically contaminated land. However, there is insufficient information available to assess the feasibility of this remediation approach. This paper presents a comprehensive literature-based evaluation of inter-varietal variation in accumulation of Cs and Sr in crop plants. Thirty-seven publications studying 27 plant species were identified as appropriate for these analyses. Inter-varietal variation was expressed at the ratio of the maximum to minimum observed concentrations for a given crop species and element and ranged from 1.0 to 6.3 and from 1.0 to 4.5 for Cs and Sr respectively. This variation suggests that exploitation of inter-varietal variation could be used in some crop species to reduce the transfer of these radionuclides to a similar extent to existing remediation strategies. Low-Sr accumulating varieties were also found to have lower concentrations of Ca, whereas low Cs-accumulating varieties were not shown to have low K accumulation. Concentrations of Cs and Sr in plants were not related, suggesting that finding varieties displaying low accumulation of both Sr and Cs may not be feasible. Varietal selection could be an effective remediation strategy, and could be used in combination with other existing methods, such as fertilisation and ploughing. However, a thorough investigation of species contributing the most to ingestion doses is recommended to fully determine the feasibility of varietal selection as a remediation strategy. The reproducibility of inter-varietal variation between sites and growing seasons should be the focus of future research.

  5. Structure and properties of molecular and ionic clusters in vapour over caesium fluoride

    Science.gov (United States)

    Mwanga, Stanley F.; Pogrebnaya, Tatiana P.; Pogrebnoi, Alexander M.

    2015-06-01

    The properties of neutral molecules Cs2F2, Cs3F3, and Cs4F4, and positive and negative cluster ions Cs2F+, CsF2-, Cs3F2+, Cs2F3-, Cs4F3+, and Cs5F4+ were studied by several of quantum chemical methods implementing density function theory and Möller-Plesset perturbation theory of second and fourth orders. For all species, the equilibrium geometrical structure and vibrational spectra were determined. Different isomers have been revealed for the trimer neutral molecule Cs3F3; pentaatomic, both positive and negative, Cs3F2+, Cs2F3-; and heptaatomic Cs4F3+ ions. The most abundant isomers in the saturated vapour were determined. Enthalpies of dissociation reactions and enthalpies of formation of the species were obtained.

  6. Electronic structure and luminescence of tellurium (IV) halide complexes with guanidine and caesium cations

    Science.gov (United States)

    Dotsenko, A. A.; Shcheka, O. L.; Vovna, V. I.; Korochentsev, V. V.; Mirochnik, A. G.; Sedakova, T. V.

    2016-04-01

    The present paper continues a series of publications on the investigation of complex compounds of s2 ions and their properties. The structure of the valence levels of Cs2TeX6, (HGu)2TeCl6 complexes (where X = Cl, Br; HGu+ - guanidinium) is examined, the orbital nature of luminescence excitation is established, and the relationship of properties with the electronic structure is determined by means of X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT).

  7. Dominant wing spectroscopy of energy pooling collisions near the boundary layer involving thermal caesium vapour

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We have observed the dominant wing spectroscopy of energy pooling collision near the boundary layer involving Cs atoms under the condition of moderate-to-high optical depths at line-centre. It appears from our experimental investigations that the energy-pooling fluorescence presents about 16 spectral lines, and all the lines can be assigned to the Cs atomic transitions. We find that all lines of the energy-pooling retrofluorescence from the heated Cs atomic vapour cell show two-peak profiles. In addition, its pumping power linear dependence in the energy pooling process has been measured and analysed.

  8. Magic Wavelength for Caesium Transition Line 6S1/2 -6P3/2

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yu-Nan; ZHOU Xiao-Ji; CHEN Jing-Biao; CHEN Xu-Zong

    2006-01-01

    @@ We investigate the magic wavelengths of the trapping laser for 6S1/2 - 6P3/2 of the Cs atom in a region where the optical shift between two different states can be eliminated. For fine levels and linear polarized laser they are 930.4 nm and 937.2nm. The magic wavelengths range from 927. 7nm to 945.0nm for circle-polarized perturbing laser. Effects of nuclear spin, the hyper-fine Zeeman levels, and the polarization of the light, which generate different magic wavelengths, are further discussed.

  9. Review of the Development of Caesium Iodide Photocathodes for Application to Large RICH Detectors

    CERN Document Server

    Amadon, A; CERN. Geneva; Bourgeois, P; Braem, André; Breskin, Amos; Buzulutskov, A F; Chechik, R; Coluzza, C; Di Mauro, A; Friese, J; Homolka, J; Ljubicic, A; Margaritondo, G; Miné, P; Nappi, E; Dell'Orto, T; Paic, G; Piuz, François; Posa, F; Santiard, Jean-Claude; Sgobba, Stefano; Vasileiadis, G; Williams, T D

    1995-01-01

    CsI photocathodes were studied in order to evaluate their potential use as large photo converters in RICH detectors for the PID system at ALICE (LHC in heavy-ion collider mode). It has been demonstrated that a quantum efficiency comparable to the reference value obtained on small samples can be obtiained on CsI layers evaporated on large pad electrodes operated in a MWPC at atmospheric pressure. We present a survey of the results obtained in the laboratory on small samples irradiatedwtih UV-monochromatic beams and with RICH detectors of proximity-focusing geometry at a 3 GeV/c pion beam.

  10. Polonium-210 and Caesium-137 in lynx (Lynx lynx), wolverine (Gulo gulo) and wolves (Canis lupus).

    Science.gov (United States)

    Gjelsvik, Runhild; Holm, Elis; Kålås, John Atle; Persson, Bertil; Asbrink, Jessica

    2014-12-01

    Wolves, lynx and wolverines are on the top of the food-chain in northern Scandinavia and Finland. (210)Po and (137)Cs have been analysed in samples of liver, kidney and muscle from 28 wolves from Sweden. In addition blood samples were taken from 27 wolves. In 9 of the wolves, samples of muscle, liver and blood were analysed for (210)Po. Samples of liver and muscle were collected from 16 lynx and 16 wolverines from Norway. The liver samples were analysed for (210)Po and (137)Cs. Only (137)Cs analyses were carried out for the muscle samples. The wolves were collected during the winter 2010 and 2011, while the samples for lynx and wolverines were all from 2011. The activity concentrations of (210)Po in wolves were higher for liver (range 20-523 Bq kg(-1) d.w.) and kidney (range 24-942 Bq kg(-1) d.w.) than muscle (range 1-43 Bq kg(-1) d.w.) and blood (range 2-54 Bq kg(-1) d.w.). Activity ratios, (210)Po/(210)Pb, in wolf samples of muscle, liver and blood were in the ranges 2-77, 9-56 and 2-54. Using a wet weight ratio of 3.8 the maximal absorbed dose from (210)Po to wolf liver was estimated to 3500 μGy per year. Compared to wolf, the ranges of (210)Po in liver samples were lower in lynx (range 22-211 Bq kg(-1) d.w.) and wolverine (range16-160 Bq kg(-1) d.w.). Concentration of (137)Cs in wolf samples of muscle, liver, kidney and blood were in the ranges 70-8410 Bq kg(-1) d.w., 36-4050 Bq kg(-1) d.w., 31-3453 Bq kg(-1) d.w. and 4-959 Bq kg(-1) d.w., respectively. (137)Cs in lynx muscle and liver samples were in the ranges 44-13393 Bq kg(-1) d.w. and 125-10260 Bq kg(-1) d.w. The corresponding values for (137)Cs in wolverine were 22-3405 Bq kg(-1) d.w. for liver and 53-4780 Bq kg(-1) d.w. for muscle. The maximal absorbed dose from (137)Cs to lynx was estimated to 3000 μGy per year.

  11. Fast RICH Detector with a Caesium Iodide Photocathode at Atmospheric Pressure

    CERN Document Server

    Di Mauro, A; CERN. Geneva; Ljubicic, A; Paic, G; Piuz, François; Posa, F; Ribeiro, R S; Scognetti, T; Williams, T D

    1994-01-01

    CsI photocathodes of 30 30 cm2 size have been operated in a fast RICH detector composed of a NaF radiator and a multiwire proportional chamber with a cathode-pad readout. Results are presented from tests with a 3 GeV / c proton beam. A Cherenkov angular resolution of 8 mrad is obtained by detecting a mean of 8 photoelectrons per ring. Methods are described for counting the Cherenkov photon and evaluating the differential quantum efficiency of the CsI photocathode. The results obtained with photons impinging at a large angle on the CsI layer are presented and discussed in comparison with higher quantum efficiencies observed under different experimental conditions.

  12. A versatile dual-species Zeeman slower for caesium and ytterbium

    Science.gov (United States)

    Hopkins, S. A.; Butler, K.; Guttridge, A.; Kemp, S.; Freytag, R.; Hinds, E. A.; Tarbutt, M. R.; Cornish, S. L.

    2016-04-01

    We describe the design, construction, and operation of a versatile dual-species Zeeman slower for both Cs and Yb, which is easily adaptable for use with other alkali metals and alkaline earths. With the aid of analytic models and numerical simulation of decelerator action, we highlight several real-world problems affecting the performance of a slower and discuss effective solutions. To capture Yb into a magneto-optical trap (MOT), we use the broad 1S0 to 1P1 transition at 399 nm for the slower and the narrow 1S0 to 3P1 intercombination line at 556 nm for the MOT. The Cs MOT and slower both use the D2 line (62S1/2 to 62P3/2) at 852 nm. The slower can be switched between loading Yb or Cs in under 0.1 s. We demonstrate that within a few seconds the Zeeman slower loads more than 109 Yb atoms and 108 Cs atoms into their respective MOTs. These are ideal starting numbers for further experiments on ultracold mixtures and molecules.

  13. Modelling transport and deposition of caesium and iodine from the Chernobyl accident using the DREAM model

    Directory of Open Access Journals (Sweden)

    J. Brandt

    2002-06-01

    Full Text Available A tracer model, DREAM (the Danish Rimpuff and Eulerian Accidental release Model, has been developed for modelling transport, dispersion and deposition (wet and dry of radioactive material from accidental releases, as the Chernobyl accident. The model is a combination of a Lagrangian model, that includes the near source dispersion, and an Eulerian model describing the long-range transport. The performance of the transport model has previously been tested within the European Tracer Experiment, ETEX, which included transport and dispersion of an inert, non-depositing tracer from a controlled release. The focus of this paper is the model performance with respect to the deposition of 137Cs, 134Cs and 131I from the Chernobyl accident, using different relatively simple and comprehensive parameterizations. The performance, compared to measurements, of different combinations of parameterizations of wet and dry deposition schemes has been evaluated, using different statistical tests.

  14. Iodine-129 and Caesium-137 in Chernobyl contaminated soil and their chemical fractionation

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Fogh, C.L.; Kucera, J.

    2003-01-01

    Soil samples from areas in Belarus, Russia and Sweden contaminated by the Chernobyl accident were analysed for I-129 by radiochemical neutron activation analysis, as well as for Cs-137 by gamma-spectrometry. The atomic ratio of I-129/(CS)-C-137 in the upper layer of the examined soil cores ranged...

  15. A versatile dual-species Zeeman slower for caesium and ytterbium

    CERN Document Server

    Hopkins, S A; Freytag, R; Guttridge, A; Kemp, S; Hinds, E A; Tarbutt, M R; Cornish, S L

    2015-01-01

    We describe the design, construction and operation of a versatile dual-species Zeeman slower for both Cs and Yb, which is easily adaptable for use with other alkali metals and alkaline earths. With the aid of analytic models and numerical simulation of decelerator action, we highlight several real-world problems affecting the performance of a slower and discuss effective solutions. To capture Yb into a magneto-optical trap (MOT), we use the broad $^1S_0$ to $^1P_1$ transition at 399 nm for the slower and the narrow $^1S_0$ to $^3P_1$ intercombination line at 556 nm for the MOT. The Cs MOT and slower both use the D2 line ($6^2S_{1/2}$ to $6^2P_{3/2}$) at 852 nm. We demonstrate that within a few seconds the Zeeman slower loads more than $10^9$ Yb atoms and $10^8$ Cs atoms into their respective MOTs. These are ideal starting numbers for further experiments on ultracold mixtures and molecules.

  16. Beta-decay energies and masses of neutron-deficient rubidium and caesium isotopes

    CERN Document Server

    D'Auria, J M; Westgaard, L; Nyman, G H; Peuser, P; Roeckl, E; Otto, H

    1976-01-01

    Total beta-decay energies were measured by a beta-gamma coincidence method for /sup 76/Rb, /sup 78/Rb, /sup 118/Cs, /sup 120/Cs and /sup 122/Cs. The resulting Q-values and masses together with experimental data from the literature are compared with mass formulae, with particular emphasis on Kr and Rb isotopes in the N=Z region.

  17. Iodine-129, iodine-127 and caesium-137 in the environment: soils from Germany and Chile.

    Science.gov (United States)

    Daraoui, A; Michel, R; Gorny, M; Jakob, D; Sachse, R; Synal, H-A; Alfimov, V

    2012-10-01

    Soil profiles from Bavaria in southern Germany and from Chile were analysed for (129)I by accelerator mass spectrometry (AMS), for (127)I by inductively coupled plasma mass spectrometry (ICP-MS), and for (137)Cs by gamma-spectrometry. The mean deposition density of (137)Cs in soils from Bavaria was (41×1.5(±1)) kBq m(-2) (geometric mean and geometric standard deviation), originating mostly from the Chernobyl fall-out. The deposition density of (129)I in these soils was (109×1.5(±1)) mBq m(-2). The dominant sources of (129)I in Bavaria are, however, the reprocessing plants La Hague and Sellafield and not the Chernobyl fall-out. The (129)I/(127)I isotopic ratios of the Bavarian soils were between 10(-7) and 10(-10), i.e. 10(2)-10(5) times higher than the ratios observed for the samples from Chile. The (129)I integral deposition densities in Chile, Easter Island and Antarctica were between 0.3 mBq m(-2) and 2 mBq m(-2). In these soils, the observed (129)I/(127)I ratios were about 10(-12). The soils from Chile allow the determination of the (129)I fall-out from the atmospheric nuclear weapons explosions undisturbed from contaminations due to releases from reprocessing plants. An upper limit of the integral (129)I deposition density of the atmospheric nuclear weapons explosions on the Southern Hemisphere (27°S) is about 1 mBq m(-2). Finally, the dependence of the migration behaviour of (137)Cs, (127)I and of (129)I on the soil properties is discussed. It turns out that there is a distinctly different behaviour of (127)I, (129)I, and (137)Cs in the soils exhibiting different sorption mechanisms for old and recent iodine as well as for (137)Cs.

  18. Modelling transport and deposition of caesium and iodine from the Chernobyl accident using the DREAM model

    Directory of Open Access Journals (Sweden)

    J. Brandt

    2002-01-01

    Full Text Available A tracer model, DREAM (the Danish Rimpuff and Eulerian Accidental release Model, has been developed for modelling transport, dispersion and deposition (wet and dry of radioactive material from accidental releases, as the Chernobyl accident. The model is a combination of a Lagrangian model, that includes the near source dispersion, and an Eulerian model describing the long-range transport. The performance of the transport model has previously been tested within the European Tracer Experiment, ETEX, which included transport and dispersion of an inert, non-depositing tracer from a controlled release. The focus of this paper is the model performance with respect to the total deposition of  137Cs, 134Cs and 131I from the Chernobyl accident, using different relatively simple and comprehensive parameterizations for dry- and wet deposition. The performance, compared to measurements, of using different combinations of two different wet deposition parameterizations and three different parameterizations of dry deposition has been evaluated, using different statistical tests. The best model performance, compared to measurements, is obtained when parameterizing the total deposition combined of a simple method for dry deposition and a subgrid-scale averaging scheme for wet deposition based on relative humidities. The same major conclusion is obtained for all the three different radioactive isotopes and using two different deposition measurement databases. Large differences are seen in the results obtained by using the two different parameterizations of wet deposition based on precipitation rates and relative humidities, respectively. The parameterization based on subgrid-scale averaging is, in all cases, performing better than the parameterization based on precipitation rates. This indicates that the in-cloud scavenging process is more important than the below cloud scavenging process for the submicron particles and that the precipitation rates are relatively uncertain in the meteorological model compared to the relative humidity. Relatively small differences are, however, seen in the statistical tests between the three different parameterizations of dry deposition.

  19. THE POTENTIAL MODEL INVESTIGATION OF STARK EFFECT IN CAESIUM RYDBERG STATE ATOMS AND COMPARISON WITH EXPERIMENT

    Institute of Scientific and Technical Information of China (English)

    HU ZHENG-FA; ZHOU SHI-KANG; GONG SHUN-SHENG; ZHAN MING-SHENG

    2000-01-01

    The potential model method for computation of Stark structure of Cs Rydberg states atoms and oscillator strength is described,for external electric fields varying from 0 to 600V/cm.Anticrossing,l-mixing and n-mixing phenomena are observed clearly from the map of Stark.Corresponding experiment is performed under the same condition,and the two results are in good agreement with each other within the experimental uncertainty.

  20. Laser spectroscopy of sub-micrometre- and micrometre-thick caesium-vapour layers

    Energy Technology Data Exchange (ETDEWEB)

    Cartaleva, S; Krasteva, A; Slavov, D; Todorov, P; Vaseva, K [Institute of Electronics, Bulgarian Academy of Sciences, boul. Tzarigradsko shosse 72, 1784 Sofia (Bulgaria); Moi, L [CNISM and Physics Department, University of Siena, via Roma 56, 53100 Siena - Italy (Italy); Sargsyan, A; Sarkisyan, D [Institute for Physical Research, National Academy of Sciences of Armenia, Ashtarak-0203 (Armenia)

    2013-09-30

    We present high resolution laser spectroscopy of Cs vapours confined in a unique optical cell of sub-micrometric and micrometric thickness, where a strong spatial anisotropy is present for the time of interaction between the atoms and laser radiation. Similarly to the spectra of selective specular reflection, the Doppler-free spectra of absorption and fluorescence are observed, not revealing cross-over resonances that will be useful for frequency stabilisation, provided the cell is cheap and compact. A new resonance in the fluorescence of closed transition is studied, demonstrating its high sensitivity to elastic atom – atom and atom – dielectric surface collisions. The theoretical modelling performed is in agreement with the experimental observations. (laser spectroscopy)

  1. Bond length variation with coverage for caesium adsorption on Si{111} (7 × 7)

    Science.gov (United States)

    Batchelor, D. R.; King, D. A.

    1991-11-01

    The adsorption of Cs on the Si{111} (7 × 7) surface has been studied using SEXAFS. A contraction is observed in the CsSi bond length from 3.79±0.04 Å at low to 3.50±0.04 Å at saturation coverage. At the lower coverage, a longer bond length can be attributed to a degree of ionicity in the CsSi surface bond, due to charge transfer from Cs to the Si. The saturation coverage bond length is consistent with covalent bonding and at this coverage a second site is also populated which has CsSi bond length of 4.68±0.06 Å.

  2. Transfer factor of caesium-137 in natural and agricultural grass ecosystems in the area of Plavsk radioactive spot, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Paramonova, Tatiana A.; Machaeva, Ekaterina N. [Radioecology and Ecotoxicology Department of Soil Science Faculty, Lomonosov Moscow State University, 119234 Moscow (Russian Federation); Belyaev, Vladimir R. [Laboratory of soil erosion and fluvial processes of Geography Faculty, Lomonosov Moscow State University, 119234 Moscow (Russian Federation)

    2014-07-01

    Root uptake and translocation of ¹³⁷Cs from soil to plant is the key for estimation of general ecological situation and land use on radioactive contaminated territories. There are numerous researches concerning the relationship between the level of the radionuclide presence in soils and its accumulation in vegetation that usually describes as transfer factor (TF) for ¹³⁷Cs (the ratio of the specific ¹³⁷Cs activity in the plant tissue and the soil). But in most cases only edible organs or above-ground parts of plants are taken into account in evaluating TF. It is reasonable from the standpoint of practical use, but does not provide accurate information in the study of ¹³⁷Cs biogeochemical cycle features. The study of the ¹³⁷Cs root uptake from the radioactive contaminated chernozem soil and its distribution between above-ground and below-ground fractions of grass vegetation was conducted in the natural conditions on the territory of Plavsk radioactive spot (Tula region, Russia)~25 years after Chernobyl accident. The main crops of field rotation in this landscape (wheat, barley, potatoes, rape, maize) which occupy watersheds and slopes with arable chernozems contaminated at a level 460-670 Bq/kg (170-220 kBq/m²) and natural grassland ecosystems which occupy lower parts of slopes and flood plains with dry and wet meadows contaminated at a level 620-710 Bq/kg (210-250 kBq/m²) were examined. Total accumulation of ¹³⁷Cs in vegetation strongly depends on the level of soil radioactive contamination (correlation coefficient 0.87). So specific ¹³⁷Cs activity in vegetation of meadows (103-160 Bq/kg) in general more than one in agricultural crops (9-92 Bq/kg). Other reason may be the predominance of perennial herbs in natural meadows whereas agricultural systems contain annual crops. The values of ¹³⁷Cs TF in the studied ecosystems vary within a relatively narrow range: from 0.01 (rape) to 0.20 (wet meadow), that confirms the discrimination of the radionuclide root uptake. At the same time the distribution of ¹³⁷Cs between above-ground and below-ground fractions of plants in all observed cases is quite non-uniformly: below-ground parts of vegetation accumulate 3-5 times more than above-ground ones. An exception is potatoes agrocenosis where the TF values for different parts are almost identical, but below-ground fraction of potatoes consists of grater modified shoots, but no roots. There is a pronounceable difference in ¹³⁷Cs TF values for root tissues of various plant associations. The highest TF values in below-ground fraction are typical for vegetation with agricultural or wild cereals (0.15-0.26) having fibrous root system, the lowest TF values are characterized for rape agrocenosis (0.02) having stem root system. Thus, the major differences in the ¹³⁷Cs TF from contaminated soil to plant may be closely related to the features of the root system and the further translocation of the radionuclide into shoot, which requires quantitative account of ¹³⁷Cs accumulation not only in above-ground green parts, but also in roots. (authors)

  3. Ocean dynamic processes causing spatially heterogeneous distribution of sedimentary caesium-137 massively released from the Fukushima Daiichi Nuclear Power Plant

    Science.gov (United States)

    Higashi, H.; Morino, Y.; Furuichi, N.; Ohara, T.

    2015-12-01

    Massive amounts of anthropogenic radiocaesium 137Cs that were released into the environment by the Fukushima Daiichi Nuclear Power Plant accident in March 2011 are widely known to have extensively migrated to Pacific Ocean sediment off of eastern Japan. Several recent reports have stated that the sedimentary 137Cs is now stable with a remarkably heterogeneous distribution. The present study elucidates ocean dynamic processes causing this heterogeneous sedimentary 137Cs distribution in and around the shelf off Fukushima and adjacent prefectures. We performed a numerical simulation of oceanic 137Cs behaviour for about 10 months after the accident, using a comprehensive dynamic model involving advection-diffusion transport in seawater, adsorption and desorption to and from particulate matter, sedimentation and suspension on and from the bottom, and vertical diffusion transport in the sediment. A notable simulated result was that the sedimentary 137Cs significantly accumulated in a swath just offshore of the shelf break (along the 50-100 m isobath) as in recent observations, although the seabed in the entire simulation domain was assumed to have ideal properties such as identical bulk density, uniform porosity, and aggregation of particles with a single grain diameter. This result indicated that the heterogeneous sedimentary 137Cs distribution was not necessarily a result of the spatial distribution of 137Cs sediment adsorptivity. The present simulation suggests that the shape of the swath is mainly associated with spatiotemporal variation between bottom shear stress in the shallow shelf (< 50 m depths) and that offshore of the shelf break. In a large part of the shallow shelf, the simulation indicated that strong bottom friction suspending particulate matter from the seabed frequently occurred via a periodic spring tide about every 2 weeks and via occasional strong wind. The sedimentary 137Cs thereby could hardly stay on the surface of the seabed with the result that the simulated sediment-surface 137Cs activity tended to decrease steadily for a long term after the initial 137Cs migration. By contrast, in the offshore region, neither the spring tide nor the strong wind caused bottom disturbance. Hence, the particulate matter incorporated with 137Cs, which was horizontally transported from the adjacent shallow shelf, readily settled and remained on the surface of the sediment just offshore of the shelf break.

  4. Uranium-236 as a new oceanic tracer: A first depth profile in the Japan Sea and comparison with caesium-137

    OpenAIRE

    Sakaguchi, Aya; Kadokura, Akinobu; Steier, Peter; Takahashi, Yoshio; Shizuma, Kiyoshi; Hoshi, Masaharu; Nakakuki, Tomoeki; Yamamoto, Masayoshi

    2012-01-01

    We present a feasibility study for using 236U as an oceanic circulation tracer based on depth profiles of 236U and 137Cs in the Japan/East Sea. The concentration of the predominantly anthropogenic 236U, measured with Accelerator Mass Spectrometry (AMS), decreased from (13±3)×106 atom/kg in surface water to (1.6±0.3)×106 atom/kg close to the sea floor (2800 m). The profile has a smooth trend with depth and concentration values are generally proportional to that of 137Cs for the same water samp...

  5. Experimental contamination of pink shrimps by caesium 137; Contamination experimentale de crevettes roses par le cesium 137

    Energy Technology Data Exchange (ETDEWEB)

    Ancellin, J.; Michon, G.; Vilquin, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    The authors describe first of all the technique used for the determination of cesium 137 concentration factors in the pink shrimp (Leander Serratus Pennant). Experiments over three months have shown that the specific activity of the shrimps becomes stable between the thirtieth and the fortieth day. The concentration factors then have values between 30 and 40. These results are similar to those obtained by other authors. (authors) [French] Les auteurs decrivent tout d'abord la technique utilisee pour la determination des facteurs de concentration du Cesium 137 chez la crevette rose (Leander Serratus Pennant). Le resultat des experimentations menees pendant trois mois montre que l'activite specifique des crevettes se stabilise entre le trentieme et le quarantieme jour. Les facteurs de concentration se situent alors entre 30 et 40, Ces donnees sont comparables a celles obtenues par d'autres auteurs. (auteur)

  6. Modelling of long-term behaviour of caesium and strontium radionuclides in the Arctic environment and human exposure

    Energy Technology Data Exchange (ETDEWEB)

    Golikov, Vladislav E-mail: bazil@sg5816.spb.edu; Logacheva, Irina; Bruk, Gennadi; Shutov, Vladimir; Balonov, Mikhail; Strand, Per; Borghuis, Sander; Howard, Brenda; Wright, Simon

    2004-07-01

    In this paper a compartment model of the highly vulnerable Arctic terrestrial food chain 'lichen-reindeer-man' is outlined. Based upon an analysis of measured {sup 137}Cs and {sup 90}Sr contents in lichen and reindeer meat from 1961 up to 2001, site specific model parameters for two regions in north-western Arctic Russia and for Kautokeino municipality in Arctic Norway have been determined. The dynamics of radionuclide activity concentrations in the 'lichen-reindeer-man' food chain for all areas was satisfactorily described by a double exponential function with short-term and long-term effective ecological half-lives between 1-2 and 10-12 years, respectively, for both {sup 137}Cs and {sup 90}Sr. Using parameter values derived from the model, life-time internal effective doses due to consumption of reindeer meat by reindeer-breeders after an assumed single pulse deposit of 1 kBq m{sup -2} of {sup 137}Cs were estimated to be 11.4 mSv (Kola Peninsula), 5 mSv (Nenets Autonomous Area), and 2 mSv (Kautokeino, Norway). Differences in vulnerability to radiocaesium deposition were due to differences in transfer between lichen and reindeer and in diet between the three regions.

  7. Modelling of long-term behaviour of caesium and strontium radionuclides in the Arctic environment and human exposure.

    Science.gov (United States)

    Golikov, Vladislav; Logacheva, Irina; Bruk, Gennadi; Shutov, Vladimir; Balonov, Mikhail; Strand, Per; Borghuis, Sander; Howard, Brenda; Wright, Simon

    2004-01-01

    In this paper a compartment model of the highly vulnerable Arctic terrestrial food chain "lichen-reindeer-man" is outlined. Based upon an analysis of measured (137)Cs and (90)Sr contents in lichen and reindeer meat from 1961 up to 2001, site specific model parameters for two regions in north-western Arctic Russia and for Kautokeino municipality in Arctic Norway have been determined. The dynamics of radionuclide activity concentrations in the "lichen-reindeer-man" food chain for all areas was satisfactorily described by a double exponential function with short-term and long-term effective ecological half-lives between 1-2 and 10-12 years, respectively, for both (137)Cs and (90)Sr. Using parameter values derived from the model, life-time internal effective doses due to consumption of reindeer meat by reindeer-breeders after an assumed single pulse deposit of 1 kBq m(-2) of (137)Cs were estimated to be 11.4 mSv (Kola Peninsula), 5 mSv (Nenets Autonomous Area), and 2 mSv (Kautokeino, Norway). Differences in vulnerability to radiocaesium deposition were due to differences in transfer between lichen and reindeer and in diet between the three regions.

  8. New scheme of the microwave signal formation for quantum frequency standard on the atoms of caesium-133

    Science.gov (United States)

    Petrov, A. A.; Davydov, V. V.

    2016-11-01

    In present work several directions of quantum frequency standard modernization are considered. A new implementation of a frequency synthesizer and a magnetic field control unit are presented. Experimental study of a frequency synthesizer showed improvement parameters of a microwave-excitation signal, such as step frequency tuning, time frequency tuning, range of generating frequencies and spectral characteristics. Magnetic field control unit eliminates one of the most important perturbing factors affecting the long-term frequency stability. Daily frequency stability of quantum frequency standard improved on 15%.

  9. Estimating sediment and caesium-137 fluxes in the Ribble Estuary through time-series airborne remote sensing.

    Science.gov (United States)

    Wakefield, R; Tyler, A N; McDonald, P; Atkin, P A; Gleizon, P; Gilvear, D

    2011-03-01

    High spatial and temporal resolution airborne imagery were acquired for the Ribble Estuary, North West England in 1997 and 2003, to assess the application of time-series airborne remote sensing to quantify total suspended sediment and radionuclide fluxes during a flood and ebb tide sequence. Concomitant measurements of suspended particulate matter (SPM) and water column turbidity were obtained during the time-series image acquisition for the flood and ebb tide sequence on the 17th July 2003 to verify the assumption of a vertically well mixed estuary and thus justifying the vertical extrapolation of spatially integrated estimate of surface SPM. The ¹³⁷Cs activity concentrations were calculated from a relatively stable relationship between SPM and ¹³⁷Cs for the Ribble Estuary. Total estuary wide budgets of sediment and ¹³⁷Cs were obtained by combining the image-derived estimates of surface SPM and ¹³⁷Cs with estimates of water volume from a two-dimensional hydrodynamic model (VERSE) developed for the Ribble Estuary. These indicate that around 10,000 tons of sediment and 2.72 GBq of ¹³⁷Cs were deposited over the tidal sequence monitored in July 2003. This compared favourably with bed height elevation change estimated from field work. An uncertainty analysis on the total sediment and ¹³⁷Cs flux yielded a total budget of the order of 40% on the final estimate. The results represent a novel approach to providing a spatially integrated estimate of the total net sediment and radionuclide flux in an intertidal environment over a flood and ebb tide sequence.

  10. Optical pumping and population transfer of nuclear-spin states of caesium atoms in high magnetic fields

    Institute of Scientific and Technical Information of China (English)

    Luo Jun; Sun Xian-Ping; Zeng Xi-Zhi; Zhan Ming-Sheng

    2007-01-01

    Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti:sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable diode laser. Furthermore, the state population transfer among the of Cs in the ground state due to stochastic collisions between Cs atoms and buffer-gas molecules, is studied at different of the hyperfine interaction can strongly cause the state population transfer and spin-state interchange among the hyperfine Zeeman sublevels. The calculated results maybe explain the steady-state population in hyperfine Zeeman sublevels in terms of rates of optical-pumping, electron-spin flip, nuclear spin flip, and electron-nuclear spin flip-flop transitions among the hyperfine Zeeman sublevels of the ground state of Cs atoms. This method may be applied to the nuclear-spin-based solid-state quantum computation.

  11. The uptake and storage of caesium and strontium by spring wheat - a modelling study based on a field experiment

    Energy Technology Data Exchange (ETDEWEB)

    Gaerdenaes, Annemieke I.; Linnea Berglund, S.; Bengtsson, Stefan B.; Rosen, Klas [Dept. of Soil and Environment, Swedish University of Agricultural Sciences (SLU), P.O. Box 7001, 750 07 Uppsala (Sweden)

    2014-07-01

    The aim was to model, quantify, and analyse the dynamics of uptake (foliar and root) and grain storage of wet-deposited radionuclides by a growing crop. The dynamic trace element model, Tracey, for terrestrial ecosystems was used after extension with descriptions for contamination by wet-deposition, interception, and foliar uptake. Tracey contains two alternative root uptake descriptions, one driven by transpiration and one by growth. Radionuclide fluxes were assumed proportional to the corresponding water or carbon fluxes in the soil-plant-atmosphere system, simulated with the CoupModel. The extended Tracey was calibrated against data from the wet-deposition experiment at Ultuna, central Sweden. {sup 134}Cs and {sup 85}Sr were deposited on spring wheat at six growth stages in 2010 and 2011. The sensitivity for different radionuclide, plant, and soil properties were assessed by Monte Carlo simulations using the sensitivity toolbox Eikos. One thousand simulations were made for each of the 48 scenarios (2 radionuclides, 2 root uptake approaches, 6 deposition treatments, 2 years). The simulated dynamics of grains' storage of radionuclides were accepted if the simulated values were within the 95% confidence interval of the measured values at all available samplings of a deposition treatment. A ten percentage of all {sup 134}Cs and {sup 85}Sr simulations were accepted. Highest percentage of accepted simulations was found for the scenarios with deposition shortly before harvest, indicating that the added model descriptions of deposition and interception performed well. The model mimicked well that the grain storage of radionuclides increased exponentially the later in the growing season the deposition took place; the storage of radionuclides when deposited at full ripening was 250 times higher than the storage when deposition took place at tillering. The model results confirmed that foliar uptake i.e. direct atmosphere-plant transfer, fully dominates total plant uptake when deposition takes place during the growing season. The estimated accumulated foliar uptake formed on average 99% of the Cs and 93% of Sr total plant uptake. We identified the governing factors of radionuclide storage in grains and how they varied with growth stage; the stem and leaves fixation rates dominate before flowering; the flowers/grain fixation rates dominate between flowering and ripening; and the interception retention capacity of the grains dominates from full ripening. We conclude that Tracey can accurately simulate the storage dynamics of radionuclides in plant parts that are a major ingredient in human food. We showed the dependency of the storage dynamics on the local weather, growth and soil conditions. The model and results can be used to tailor counter-measures to local conditions in the case of a radioactive deposition and to improve preparedness for radioactive deposition on growing crops. (authors)

  12. Caesium-137 root uptake by agricultural and wild crops in post-Chernobyl landscape: the possibilities for phytoremediation?

    Science.gov (United States)

    Paramonova, Tatiana; Shamshurina, Eugenia; Komissarova, Olga; Belyaev, Vladimir

    2015-04-01

    In spite of long term period after Chernobyl fallout (≈25 years after the accident) the level of Cs-137 in soils of contaminated landscapes remains several times more than radiation safety standard (= 37 kBq/m2). In particular, within the area of Plavsk radioactive hot spot (Tula region, Russia) current Cs-137 activities in soil are 460-500 Bq/kg (170-200 kBq/m2) on watershed, 580-680 Bq/kg (200-220 kBq/m2) in arable lower parts of slopes and 620-710 Bq/kg (210-280 kBq/m2) in untilled foots of slopes and river floodplains. To estimate the process of Cs-137 root uptake and incorporation of the radionuclide in plant tissues 6 agricultural crops of typical field rotation (spring barley, maize, summer rape, galega, potatoes, amaranth) as well as natural ecosystems of dry and wet meadows were selected for the detailed study. Total bioproductivity of agricultural crops varies between 1.7-3.9 kg/m2, natural grass ecosystems - 1.9-2.2 g/m2, and is obviously unaffected by radioactive land contamination. At the same time Cs-137 activity in total biomass slightly increases with Cs-137 activity in soil (correlation coefficient r=0.45) and with total biomass (correlation coefficient r=0.51) in the row: rape (5 Bq/kg) < amaranth, galega (17-19 Bq/kg) < barley, potatoes (31-37 Bq/kg) < maize (58 Bq/kg) < dry meadow (73 Bq/kg) < wet meadow (120 Bq/kg). Commonly, Cs-137 activity in vegetation of natural ecosystems with predominance of perennial grasses is significantly higher than in agrosystems with annual crops. But a substantial portion of Cs-137 in meadow vegetation is associated with belowground biomass, where the radionuclide's activity is 3-5 times greater than in the aboveground part. The distribution of Cs-137 activities between above- and belowground parts of agricultural crops greatly varies depending on the biological characteristics of plants: barley and maize (Gramíneae family) are also characterized by elevated Cs-137 concentrations in belowground parts (12-14 times higher than in shoots); rape (Brassicaceae family) and potatoes (Solanaceae family) are characterized by similar Cs-137 concentrations in the structural parts (but note, that belowground part of the last is mostly represented by modified shoots); while galega and amaranth (Fabaceae and Amaranthaceae families respectively) are characterized by higher Cs-137 activity in aboveground part (4-6 times more than in roots). Therefore, meadow grasses and cereals that are true accumulators of Cs-137 seem to be useless for phytoremediation purposes, as 86-97% of the radionuclide inventory is associated with roots and remains in soil after cutting of aboveground parts. On the other hand, galega and amaranth could be considered as agricultural crops potentially being used for phytoremediation, since 87-93% of Cs-137 inventory is located in shoots. Potatoes having rather high aboveground biomass and easily removed from soil underground part could be also used for phytoremediation. However, it should be clearly understood that in total Cs-137 inventory in "soil-plant" system the annual amount of the radionuclide's consumption (that may be alienated when harvesting) is less than 0.01%, while the rate of Cs-137 radioactive decay is estimated as about 2% per year. Study was conducted with the support from the Russian Foundation for Basic Research (project no. 14-05-00903).

  13. Metabolomic, proteomic and biophysical analyses of Arabidopsis thaliana cells exposed to a caesium stress. Influence of potassium supply.

    Science.gov (United States)

    Le Lay, P; Isaure, M-P; Sarry, J-E; Kuhn, L; Fayard, B; Le Bail, J-L; Bastien, O; Garin, J; Roby, C; Bourguignon, J

    2006-11-01

    The incorporation and localisation of 133Cs in a plant cellular model and the metabolic response induced were analysed as a function of external K concentration using a multidisciplinary approach. Sucrose-fed photosynthetic Arabidopsis thaliana suspension cells, grown in a K-containing or K-depleted medium, were submitted to a 1 mM Cs stress. Cell growth, strongly diminished in absence of K, was not influenced by Cs. In contrast, the chlorophyll content, affected by a Cs stress superposed to K depletion, did not vary under the sole K depletion. The uptake of Cs was monitored in vivo using 133Cs NMR spectroscopy while the final K and Cs concentrations were determined using atomic absorption spectrometry. Cs absorption rate and final concentration increased in a K-depleted external medium; in vivo NMR revealed that intracellular Cs was distributed in two kinds of compartment. Synchrotron X-ray fluorescence microscopy indicated that one could be the chloroplasts. In parallel, the cellular response to the Cs stress was analysed using proteomic and metabolic profiling. Proteins up- and down-regulated in response to Cs, in presence of K+ or not, were analysed by 2D gel electrophoresis and identified by mass spectrometry. No salient feature was detected excepting the overexpression of antioxidant enzymes, a common response of Arabidopsis cells stressed whether by Cs or by K-depletion. 13C and 31P NMR analysis of acid extracts showed that the metabolome impact of the Cs stress was also a function of the K nutrition. These analyses suggested that sugar metabolism and glycolytic fluxes were affected in a way depending upon the medium content in K+. Metabolic flux measurements using 13C labelling would be an elegant way to pursue on this line. Using our experimental system, a progressively stronger Cs stress might point out other specific responses elicited by Cs.

  14. Beta-decay energies and masses of short-lived isotopes of rubidium, caesium, francium, and radium

    CERN Document Server

    Westgaard, L; Nyman, G H; Roeckl, E

    1975-01-01

    Total decay energies have been measured for a number of neutron- deficient Rb and Cs isotopes, as well as for some neutron-rich isotopes of Fr and Ra. Mass separated sources were produced at the ISOLDE on-line separator at CERN. By applying two different beta - gamma coincidence methods, Q values or their lower limits were determined for /sup 76-78/Rb, /sup 80/Rb, /sup 121-124/Cs, /sup 222 /Fr, /sup 224-226/Fr, /sup 229/Ra and /sup 229/Ac. For many of these nuclei, the atomic mass excesses could be derived, allowing the comparison of masses of far unstable nuclei with predictions from mass formulae. The odd-odd nuclei /sup 76/Rb and /sup 78/Rb appear to be 1-1/sup 1///sub 2/ MeV more strongly bound than expected from the systematics. (70 refs).

  15. Analysis of Collisional Cross Sections of Rydberg nS and nD States of Ultracold Caesium Atoms

    Science.gov (United States)

    Feng, Zhigang; Miao, Jingyuan; Zhao, Kejia; Li, Difei; Yang, Zhijun; Wu, Fan; Wu, Zhaochun; Zhao, Jianming; Jia, Suotang

    2016-05-01

    We present a simple analytical formula derived from an existing theoretical model and a detailed theoretical investigation of effects of the van der Waals interaction and dipole-dipole interaction on collisional cross sections as functions of various parameters. We analyze the main mechanism leading to large collisional cross sections on the basis of our previous experimental results using the present formula and also analyze the effects of some other factors on collisional cross sections.

  16. Removal of radioactive caesium from low level radioactive waste (LLW) streams using cobalt ferrocyanide impregnated organic anion exchanger.

    Science.gov (United States)

    Valsala, T P; Roy, S C; J G Shah; Gabriel, J; Raj, Kanwar; Venugopal, V

    2009-07-30

    The volumes of low level waste (LLW) generated during the operation of nuclear reactor are very high and require a concentration step before suitable matrix fixation. The volume reduction (concentration) is achieved either by co-precipitating technique or by the use of highly selective sorbents and ion exchange materials. The present study details the preparation of cobalt ferrocyanide impregnated into anion exchange resin and its evaluation with respect to removal of Cs in LLW streams both in column mode and batch mode operations. The Kd values of the prepared exchanger materials were found to be very good in actual reactor LLW solutions also. It was observed that the exchanger performed very well in the pH range of 3-9. A batch size of 6 g l(-1) of the exchanger was enough to give satisfactory decontamination for Cs in actual reactor LLW streams. The lab scale and pilot plant scale performance of the exchanger material in both batch mode and column mode operations was very good.

  17. Modern parameters of caesium-137 root uptake in natural and agricultural grass ecosystems of contaminated post-Chernobyl landscape, Russia

    Directory of Open Access Journals (Sweden)

    Tatiana Paramonova

    2015-01-01

    Full Text Available The estimation of modern parameters of 137Cs root uptake was conducted in natural meadow and agricultural ecosystems of post-Chernobyl landscapes of Tula region. The agrosystems with main crops of field rotation (barley, potatoes, rape, maize occupying watersheds and slopes with arable chernozems are contaminated at a level 460-670 Bq/kg (4.7-6.0 Ci/km2; natural meadow ecosystems occupying lower parts of slopes and floodplains are contaminated at a level 620-710 Bq/kg (5.8-7.6 Ci/km2. In the arable soils 137Cs uniformly distributed to a depth of Ap horizon (20-30 cm of thickness, while in meadow soils 70-80% of the radionuclide is concentrated within the top Ad horizon (9-13 cm of thickness. These topsoil layer accords with rhizosphere zone, where >80-90% of plant roots are concentrated, and from which 137Cs is mostly consumed by vegetation. Total amount of 137Cs root uptake depends on the level of soil radioactive contamination (correlation coefficient 0.61. So 137Cs activity in meadow vegetation (103-160 Bq/kg is generally more than one in agricultural vegetation (9-92 Bq/kg. The values of 137Cs transfer factor in the studied ecosystems vary from 0.01 (rape to 0.20 (wet meadow, that confirms the discrimination of the radionuclide’s root uptake. The larger are the volume of roots and their absorbing surface, the higher are the values of transfer factor from soil to plant (correlation coefficients 0.71 and 0.64 respectively. 137Cs translocation from roots to shoots is also determined by biological features of plants. At the same level of soil contamination above-ground parts of meadow herbs accumulate more 137Cs than Gramineae species, and in agrosystems above-ground parts of weeds concentrate more 137Cs than cultivated cereals. Thus, the level of soil radioactive pollution and biological features of plants are determinants in the process of 137Cs root uptake and translocation and should be considered in land use policy.

  18. Concentration of caesium-137, cobalt-60 and potassium-40 in some wild and edible plants around the nuclear power plant in Bulgaria

    Energy Technology Data Exchange (ETDEWEB)

    Djingova, R. E-mail: rdjingova@chem.uni-sofia.bg; Kuleff, I

    2002-07-01

    The activities of {sup 137}Cs, {sup 60}Co and {sup 40}K were determined in samples of wild (Taraxacum officinale, Plantago lanceolata and Populus nigra 'Italica') and edible (vegetable, corn, fruit) plants as well as soil collected from the 30 km safety zone of the Bulgarian NPP 'Kozloduy' and comparisons with earlier measurements and analyses of samples from other regions and with literature values were performed. The derived transfer factors for {sup 137}Cs and {sup 40}K from soil to plants ranged between 0.002 and 0.009 for {sup 137}Cs, and between 0.09 and 0.35 for {sup 40}K. The individual effective dose (calculated from the present results and data on the activity of other foodstuffs and from information about dietary habits) comprises 4.5% of the annual dose limit.

  19. Human metabolism and ecological transfer of radioactive caesium. Comparative studies of Chernobyl debris and nuclear weapons fallout, in southern Sweden and in Bryansk, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Raeaef, C.L

    2000-05-01

    The whole-body content of radiocaesium was measured in a South Swedish urban group of people residing in the city of Lund between 1960 and 1994. The results from the survey have been analysed in order to estimate the ecological half time, T{sub eff,eco} of fallout radiocaesium, and the aggregate transfer from ground deposition to man in the region. After 1987, the biological half times, T{sub e} of {sup 137}Cs and {sup 40}K in man were also determined in the reference group through whole-body content measurements in combination with 24-hour urine sampling. Relationships between 24-hour urinary excretion and body burden of {sup 137}Cs in the group together with data from the literature were then applied to urine samples collected in 1994 and 1995 from adult subjects living in the highly contaminated region of Bryansk, Russia, in order to estimate their average body burden of {sup 137}Cs. The equivalent biological half-time for {sup 137}Cs in females of the Lund reference group was, on average 66{+-}3 d, which agrees with other findings, whereas the value for the males, 81{+-}4 d, was, on average, significantly lower than what is found in the literature. This is partly explained by the elevated mean age and relatively low mean body muscle mass of the males investigated. The {sup 137}Cs from nuclear weapons tests in the 1950s and 1960s still gave a significant contribution to the total {sup 137}Cs levels in man during the post-Chernobyl study period (1987-1994). About 10% of the peak post-Chernobyl concentration level of {sup 137}Cs (3.5-4 Bq/kg) in 1987, was attributed to pre-Chernobyl {sup 137}Cs. The effective ecological half-time for {sup 137}Cs from Chernobyl was found to be 1.8{+-}0.2 y. The time-integrated aggregate transfer of {sup 137}Cs from ground deposition to mean activity concentration in man was estimated to be 0.4 Bq/kg/kBq/m{sup 2}. These values may be compared with an effective ecological half-time of 1.3 years found in the Lund reference group in the 1960s, and in time-integrated aggregate transfer factor of 4.4 Bq/kg/kBq/m{sup 2}. The average committed effective dose from ingested {sup 137}Cs Chernobyl fallout in the study group was estimated to be 0.02 mSv and from the nuclear weapons fallout to 0.20 mSv. The estimates of whole-body content of {sup 137}Cs in the Russian subjects obtained through creatinine normalisation of the {sup 137}Cs content in urine were, on average, a factor of 2 higher than estimates obtained through a potassium normalisation procedure; 55{+-}8 kBq for creatinine and 29{+-}4 kBq for potassium normalisation in the year 1994. This was due to a significant difference in the relationship between the urinary potassium and creatinine concentration between the Swedish and Russian group. The elevated potassium concentration found in the rural Russian subjects indicated a higher dietary intake of potassium, which greatly influence the accuracy and applicability of the potassium normalization method when estimating body burden of {sup 137}Cs through urine assay. It is therefore recommended not to use the potassium normalisation procedure in cases where the daily intake of potassium is unknown. The estimated body burden of {sup 137}Cs in the Bryansk group in 1994 corresponds to a contribution to the estimated annual effective dose of 1.8 mSv/y, which is approximately 200 times greater than the average annual dose received from ingested {sup 137}Cs by the subjects of the Lund reference group during the period 1987-1994.

  20. Transfer across the human gut of environmental plutonium, americium, cobalt, caesium and technetium: studies with cockles (Cerastoderma edule) from the Irish Sea.

    Science.gov (United States)

    Hunt, G J

    1998-06-01

    Our previous studies have indicated lower values of the gut transfer factor ('f1 values') for plutonium and americium in winkles (Littorina littorea) than adopted by ICRP. The present study was undertaken primarily to investigate whether this observation extends to other species. Samples of cockles (Carastoderma edule) from Ravenglass, Cumbria were eaten by volunteers who provided 24 h samples of urine and faeces. Urine samples indicated f1 values for cockles which were higher than for winkles; for plutonium these ranged overall up to 7 x 10(-4) with an arithmetic mean in the range (2-3) x 10(-4), and for americium up to 2.6 x 10(-4) with an arithmetic mean of 1.2 x 10(-4). Limited data based on volunteers eating cockles from the Solway suggest that f1 values for americium may be greater at distance from Sellafield. The measured values compare with 5 x 10(-4) used by the ICRP for environmental forms of both elements, which would appear to provide adequate protection when calculating doses from Cumbrian cockles. Data for other nuclides were obtained by analysing faecal samples from the volunteers who ate the Ravenglass cockles. Cobalt-60 showed an f1 value in the region of 0.2, twice the value currently used by ICRP. For 137Cs, variabilities were indicated in the range 0.08 to 0.43, within the ICRP value of f1 = 1.0. Technetium-99 gave f1 values up to about 0.6, in reasonable conformity with the ICRP value of 0.5.

  1. Transfer across the human gut of environmental plutonium, americium, cobalt, caesium and technetium: studies with cockles (Cerastoderma edule) from the Irish Sea

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, G.J. [CEFAS Laboratory, Lowestoft, Suffolk NR33 0HT (United Kingdom)

    1998-06-01

    Our previous studies have indicated lower values of the gut transfer factor ('f{sub L} values') for plutonium and americium in winkles (Littorina littorea) than adopted by ICRP. The present study was undertaken primarily to investigate whether this observation extends to other species. Samples of cockles (Cerastoderma edule) from Ravenglass, Cumbria were eaten by volunteers who provided 24 samples of urine and faeces. Urine samples indicated f{sub L} values for cockles which were higher than for winkles; for plutonium these ranged overall up to 7x10{sup -4} with an arithmetic mean in the range (2-3)x10{sup -4}, and for americium up to 2.6x10{sup -4} with an arithmetic mean of 1.2x10{sup -4}. Limited data based on volunteers eating cockles from the Solway suggest that f{sub L} values for americium may be greater at distance from Sellafield. The measured values compare with 5x10{sup -4} used by the ICRP for environmental forms of both elements, which would appear to provide adequate protection when calculating doses from Cumbrian cockles. Data for other nuclides were obtained by analysing faecal samples from the volunteers who ate the Ravenglass cockles. Cobalt-60 showed an f{sub L} value in the region of 0.2, twice the value currently used by ICRP. For {sup 137}Cs, variabilities were indicated in the range 0.08 to 0.43, within the ICRP value of f{sub L}=1.0. Technetium-99 gave f{sub L} values up to about 0.6, in reasonable conformity with the ICRP value of 0.5. (author)

  2. Cobalt-60 and cesium-137 for the sterilization of food. Radiation treatment of food. Mit Kobalt 60 und Caesium 137 gegen Keime in Lebensmitteln. Strahlenbehandlung von Lebensmitteln

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1990-11-01

    The brief article discusses the reasons justifying in the eyes of the authors the irradiation of food with ionizing readiation, the irradiation technique applied using cobalt-60 and cesium-137 as a radiation source, and the possible secondary effects of the method. (VHE).

  3. RBE values and repair characteristics for colo-rectal injury after caesium 137 gamma-ray and neutron irradiation. 2. Fractionation up to ten doses

    Energy Technology Data Exchange (ETDEWEB)

    Terry, N.H.A.; Denekamp, J. (Mount Vernon Hospital, Northwood (UK). Gray Lab.)

    1984-07-01

    Early and late colo-rectal damage in mice have been assessed after /sup 137/Cs ..gamma.. irradiation and 3 MeV neutrons given as 1, 2, 5 or 10 fractions. Damage was measured by early changes in body weight, the late production of short faecal pellets and the pattern of lethality after irradiation. The data have been analysed in terms of the time course of expression of damage, fractionation effects and the RBE for neutrons over a wide range of doses per fraction (0.5-12.5 Gy neutrons, 3.5-33.5 Gy ..gamma.. rays). The RBE was strongly dependent on dose per fraction because of the lack of reparable damage after neutrons. The RBE for both early and late effects was 5.0 at a neutron dose per fraction of 1 Gy. Extrapolation of the RBE data to lower doses, using the linear quadratic model, predicts a higher RBE for late (7.4-12.7) than for early damage (5.7-8.5) if ..gamma..-ray doses below 5 Gy are used.

  4. RBE values and repair characteristics for colo-rectal injury after caesium 137 gamma-ray and neutron irradiation. II. Fractionation up to ten doses.

    Science.gov (United States)

    Terry, N H; Denekamp, J

    1984-07-01

    Early and late colo-rectal damage in mice have been assessed after 137Cs gamma irradiation and 3 MeV neutrons given as 1,2,5 or 10 fractions. Damage was measured by early changes in body weight, the late production of short faecal pellets and the pattern of lethality after irradiation. The data have been analysed in terms of the time course of expression of damage, fractionation effects and the RBE for neutrons over a wide range of doses per fraction (0.5-12.5 Gy neutrons, 3.5-33.5 Gy gamma rays). An initial epithelial denudation led to an early loss of weight, maximal at 11-17 days after irradiation. A dose-dependent weight reduction persisted over the animals' life-time. Deaths after localised pelvic gamma irradiation were progressive with no sharp demarcation between early or late phases of injury. The time course for lethality was qualitatively similar after neutrons. Beyond six months the rectum became constricted by fibrosis and a higher proportion of small faecal pellets was observed. At 6-15 months relatively shallow dose-response curves were obtained for this change. The sparing effect of fractionation was marked for the gamma-irradiated mice and almost absent after neutrons. A very high repair increment (11 Gy) was seen with two gamma-ray fractions of 20 Gy. At lower doses per fraction the proportion of each gamma-ray fraction recovered was 50-69% for all assays, i.e., similar to that for other normal tissues. There was a slight enhancement in the sparing effect for the late compared with the early assays over the lower dose range. The RBE was strongly dependent on dose per fraction because of the lack of reparable damage after neutrons. The RBE for both early and late effects was 5.0 at a neutron dose per fraction of 1 Gy. Extrapolation of the RBE data to lower doses, using the linear quadratic model, predicts a higher RBE for late (7.4-12.7) than for early damage (5.7-8.5) if gamma-ray doses below 5 Gy are used.

  5. Irradiation of members of the general public from radioactive caesium following the Chernobyl reactor accident. Field studies in a highly contaminated area in the Bryansk region, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Thornberg, C

    2000-11-01

    From 1990 to 1999, estimations of the effective dose from external as well as internal irradiation from {sup 137}Cs and {sup 134}Cs were carried out for inhabitants in rural villages in the Bryansk region, Russia, highly contaminated due to the Chernobyl accident in 1986. The villages were situated about 180 km from the Chernobyl power plant and the deposition of {sup 137}Cs was in the range 0.9-2.7 MBq/m{sup 2}. Yearly expeditions were conducted in autumn by members of the Departments of Radiation Physics in Malmoe and Goeteborg, Institute of Radiation Hygiene, St. Petersburg and the the first 5 years also by the Norwegian Radiation Protection Authority. The dose levels and their change in time were estimated for various groups of the general public. The body burden of {sup 134,137}Cs and hence, the effective dose, was estimated from measurements of the urinary concentration of cesium radionuclides, together with direct measurements of the body content using a portable detector. The effective dose from external irradiation was estimated from measurements with thermoluminescent dosemeters worn by the participants during one month each year. In a special case study, the changes in biokinetics of {sup 137}Cs during pregnancy was investigated in a woman with an unintended intake of {sup 137}Cs via mushrooms from a highly contaminated forest in the area. During pregnancy there is an increased excretion of cesium resulting in a biological half-time of cesium which was 54% of the half-time before pregnancy. The ratio of the {sup 137}Cs concentration in breast milk (Bq/l) to that in the mother's body (Bq/kg) was 15% one month after the child was born. The body burden of {sup 137}Cs in the Russian individuals calculated from the concentration of {sup 137}Cs in urine showed a good agreement with the body burden estimated from in vivo measurements in the same individuals. Normalisation of the cesium concentration in the urine samples by the use of potassium or creatinine excretion was found to introduce systematic differences as well as larger spread in the calculated values of the {sup 137}Cs body burden as compared with calculations without normalisation, using the urinary concentration of {sup 137}Cs only. The yearly effective dose from external and internal irradiation to inhabitants in the Russian villages varied between 1.2 and 2.5 mSv as a mean for all villages studied between 1991 and 1998 and the internal effective dose was, on average, 30-50% of the total effective dose during that period. The effective dose from external irradiation decreased on average 15% per year, while the effective dose from internal irradiation varied, depending to a great extent on dietary habits and especially the availability of mushrooms. The cumulated effective dose for a 70-year period after the accident was calculated to be around 100 mSv with the assumption that the effective dose will decrease by only the physical decay of {sup 137}Cs (2% per year) after 1999. Individuals may receive considerably higher effective doses, up to 0.5 Sv during a life-time considering the large spread in dose values among individuals.

  6. Ocean dynamic processes causing spatially heterogeneous distribution of sedimentary caesium-137 massively released from the Fukushima Dai-ichi Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    H. Higashi

    2015-08-01

    Full Text Available Massive amounts of anthropogenic radiocaesium 137Cs that was released into the environment by the Fukushima Dai-ichi Nuclear Power Plant accident on March 2011 are widely known to have extensively migrated to Pacific oceanic sediment off of east Japan. Several recent reports have stated that the sedimentary 137Cs is now stable with a remarkably heterogeneous distribution. The present study elucidates ocean dynamic processes causing this heterogeneous sedimentary 137Cs distribution in and around the shelf off Fukushima and adjacent prefectures. We performed a numerical simulation of oceanic 137Cs behaviour for about 10 months after the accident, using a comprehensive dynamic model involving advection–diffusion transport in seawater, adsorption and desorption to and from particulate matter, sedimentation and suspension on and from the bottom, and vertical diffusion transport in the sediment. A notable simulated result was that the sedimentary 137Cs significantly accumulated in a swath just offshore of the shelf break (along the 50–100 m isobath as in recent observations, although the seabed in the entire simulation domain was assumed to have ideal properties such as identical bulk density, uniform porosity, and aggregation of particles with a single grain diameter. This result indicated that the heterogeneous sedimentary 137Cs distribution was not necessarily a result of the spatial distribution of 137Cs sediment adsorptivity. The present simulation suggests that the shape of the swath is mainly associated with spatiotemporal variation between bottom shear stress in the shallow shelf (137Cs thereby could hardly stay on the surface of the seabed with the result that the simulated sediment-surface 137Cs activity tended to decrease steadily for a long term after the initial 137Cs migration. By contrast, in the offshore region, neither the spring tide nor the strong wind caused bottom disturbance. Hence, the particulate matter incorporated with 137Cs, which was horizontally transported from the adjacent shallow shelf, readily settled and remained on the surface of the sediment just offshore of the shelf break. The present simulation also clearly demonstrated that the bottom disturbance influenced the sedimentary 137Cs distributions not only horizontally but also vertically. In particular, within a part of the near-shore off the nuclear power plant, the simulation indicated that large amounts of the sedimentary 137Cs were present in both upper and deeper sediments. As a result, total sedimentary 137Cs in the entire simulation domain (1.4 x 105 km2 at the end of 2011 was 3.2 x 1015 Bq, more than 10 times that in previous estimates using samples of upper sediments.

  7. Sympathetic cooling in a rubidium cesium mixture: Production of ultracold cesium atoms; Sympathetisches Kuehlen in einer Rubidium-Caesium-Mischung: Erzeugung ultrakalter Caesiumatome

    Energy Technology Data Exchange (ETDEWEB)

    Haas, M.

    2007-07-01

    This thesis presents experiments for the production of ultracold rubidium cesium mixture in a magnetic trap. The long-termed aim of the experiment is the study of the interaction of few cesium atoms with a Bose-Einstein condensate of rubidium atoms. Especially by controlled variation of the cesium atom number the transition in the description of the interaction by concepts of the one-particle physics to the description by concepts of the many-particle physics shall be studied. The rubidium atoms are trapped in a magneto-optical trap (MOT) and from there reloaded into a magnetic trap. In this the rubidium atoms are stored in the state vertical stroke f=2,m{sub f}=2 right angle of the electronic ground state and evaporatively cooled by means of microwave-induced transitions into the state vertical stroke f=1,m{sub f}=1] (microwave cooling). The cesium atoms are also trppaed in a MOT and into the same magnetic trap reloaded, in which they are stored in the state vertical stroke f=4,m{sub f}=4 right angle of the electronic ground state together with rubidium. Because of the different hyperfine splitting only rubidium is evaporatively cooled, while cesium is cooled jointly sympathetically - i.e. by theramal contact via elastic collisions with rubidium atoms. The first two chapters contain a description of interatomic interactions in ultracold gases as well as a short summary of theoretical concepts in the description of Bose-Einstein condensates. The chapters 3 and 4 contain a short presentation of the methods applied in the experiment for the production of ultracold gases as well as the experimental arrangement; especially in the framework of this thesis a new coil system has been designed, which offers in view of future experiments additionally optical access for an optical trap. Additionally the fourth chapter contains an extensive description of the experimental cycle, which is applied in order to store rubidium and cesium atoms together into the magnetic trap. The last chapter finally contains the experimental results as well as the analysis of which. In experiments, which involve only rubidium, rubidium is coolde by means of microwave cooling; thereby an unwanted population of the state vertical stroke f=2,m{sub f}=1 right angle is observed, which hinders the condensation. The population of the state vertical stroke f=2,m{sub f}=1 right angle is systematically studied. The continuous depopulation of the state vertical stroke 2,1 right angle by means of a second microwave frequency radiated upon allows the production of rubidium condensates of 10{sup 5} atoms after 23 s evaporative cooling. By selective microwave cooling of the rubidium atoms the rubidium cesium mixtures are cooled until 700 mK. By means of a simple model the sympathetic cooling of cesium is analyzed, which allows a first characterization of the rubidium-cesium interaction.

  8. Human metabolism and ecological transfer of radioactive caesium: Comparative studies of Chernobyl debris and nuclear weapons fallout, in Southern Sweden and in Bryansk, Russia

    Science.gov (United States)

    Raaf, Christopher Leopold

    The whole-body content of radiocaesium was measured in a South-Swedish urban group of people residing in the city of Lund (55.7°N, 13.2°E) between 1960 and 1994. The results from the survey have been analysed in order to estimate the ecological half-time, Teff,eco, of fallout radiocaesium and the aggregate transfer from ground deposition to man in the region. After 1987, the biological half-times, Ts, of 137Cs and 40K in man were also determined in the reference group through whole-body content measurements in combination with 24-hour urine sampling. Relationships between 24-hour urinary excretion and body burden of 137Cs in the group together with data from the literature were then applied to urine samples collected in 1994 and 1995 from adult subjects living in the highly contaminated region of Bryansk, Russia, in order to estimate their average body burden of 137Cs. The equivalent biological half-time for 137Cs in females of the Lund reference group was, on average (+/-1 WSE), 66 +/- 3 d, which agrees with other findings, whereas the value for the males, 81 +/- 4 d, was, on average, significantly lower than what is found in the literature. This is partly explained by the elevated mean age and relatively low mean body muscle mass of the males investigated in the group during the post-Chernobyl study period. The effective ecological half-time for 137Cs from Chernobyl was found to be 1.8 +/- 0.2 y. The aggregate transfer of 137Cs from deposition to mean activity concentration in man was estimated to be 1.7 Bq kg-1/kBq m-2. These vales may be compared with an effective ecological half-time of 1.3 years found in the reference group in the 1960s, and an aggregate transfer factor of 9.8 Bq kg-1/kBq m-2. The average committed effective dose from ingested 137Cs Chernobyl fallout in the study group was estimated to be 0.02 mSv and from the nuclear weapons fallout to 0.20 mSv. The estimates of whole-body content of 137Cs in the Russian subjects obtained through creatinine normalisation of the 137Cs content in urine were, on average, a factor of 2 higher than estimates obtained through a potassium normalisation procedure; 55 +/- 8 (1 SE) kBq for creatinine and 29 +/- 4 (1 SE) kBq for potassium normalisation in the year 1994. This was due to a significant difference in the relationship between the urinary potassium and creatinine concentration between the Swedish and Russian group. The elevated potassium concentration found in the rural Russian subjects indicated a higher dietary intake of potassium, which greatly influences the accuracy and applicability of the potassium normalisation method when estimating body burden of 137Cs through urine assay. It is therefore recommended not to use the potassium normalisation procedure in cases where the daily intake of potassium is unknown. The estimated body burden of 137Cs in the Bryansk group in 1994 corresponds to a contribution to the estimated annual effective dose of 1.8 mSv y-1, which is approximately 200 times greater than the average annual dose received from ingested 137Cs by the subjects of the Lund reference group during the period 1987-1994.

  9. Caesium-137 soil-to-plant transfer for representative agricultural crops of monocotyledonous and dicotyledonous plants in post-Chernobyl steppe landscape

    Science.gov (United States)

    Paramonova, Tatiana; Komissarova, Olga; Turykin, Leonid; Kuzmenkova, Natalia; Belyaev, Vladimir

    2016-04-01

    The accident at the Chernobyl nuclear power plant in 1986 had a large-scale action on more than 2.3 million hectares agricultural lands in Russia. The area of radioactively contaminated chernozems of semi-arid steppe zone with initial levels of Cs-137 185-555 kBq/m2 in Tula region received the name "Plavsky radioactive hotspot". Nowadays, after the first half-life period of Cs-137 arable chernozems of the region are still polluted with 3-6-fold excess above the radioactive safety standard (126-228 kBq/m2). Therefore, qualitative and quantitative characteristics of Cs-137 soil-to-plant transfer are currently a central problem for land use on the territory. The purpose of the present study was revealing the biological features of Cs-137 root uptake from contaminated arable chernozems by different agricultural crops. The components of a grass mixture growing at the central part of Plavsky radioactive hotspot with typical dicotyledonous and monocotyledonous plants - galega (Galega orientalis, Fabaceae family) and bromegrass (Bromus inermis, Gramineae family) respectively - were selected for the investigation, that was conducted during the period of harvesting in 2015. An important point was that the other factors influenced on Cs-137 soil-to-plant transfer - the level of soil pollution, soil properties, climatic conditions, vegetative phase, etc. - were equal. So, biological features of Cs-137 root uptake could be estimated the most credible manner. As a whole, general discrimination of Cs-137 root uptake was clearly shown for both agricultural crops. Whereas Cs-137 activity in rhizosphere 30-cm layer of arable chernozem was 371±74 Bq/kg (140±32 kBq/m2), Cs-137 activities in plant biomass were one-two orders of magnitude less, and transfer factor (TF) values (the ratio of the Cs-137 activities in vegetation and in soil) not exceeded 0.11. At the same time bioavailability of Cs-137 for bromegrass was significantly higher than for galega: TFs in total biomass of the crops were 0.11 and 0.01 correspondingly. But the most dramatic difference between the investigated crops was connected with peculiarities of Cs-137 distribution within above- and belowground parts of biomass. While TF in aboveground fraction of galega (0.02) was slightly higher than in belowground fraction (0.01), the bulk of Cs-137 in bromegrass was detected not in shoots but in roots (TFs 0.05 and 0.11 correspondingly). More extensive examination of Cs-137 behavior in "soil-plant" systems of agricultural crops in the area of Plavsky radioactive hotspot has revealed that all investigated dicotyledonous plants with taproot system (potatoes, soya, amaranth, rape) accumulated 71±14% of Cs-137 inventories in aboveground biomass, whereas monocotyledonous plants with fibrous root system (wheat, barley, maize, cereal pasture species) deposited 94±5% of Cs-137 supplies in their belowground biomass. Thus, the first had effective biological root barrier protecting vegetation from general Cs-137 incorporation into biomass, but relatively active radionuclide translocation into shoots, while the second were characterized by slight rhizofiltration property and occurrence an additional barrier between roots and shoots determining only moderate radionuclide translocation into aboveground biomass. Such biological features should be taken into account in deciding on rehabilitation strategy of radioactively contaminated lands. The study was conducted with the support from the Russian Foundation for Basic Research (project no. 14-05-00903).

  10. Experimental Study on the Stark Effect of Caesium Rydberg Atoms in an Electric Fields%Rydberg态Cs原子的Stark效应的实验研究

    Institute of Scientific and Technical Information of China (English)

    胡正发; 柳晓军; 龚顺生; 詹明生; 周士康

    2000-01-01

    With an atomic beam apparatus and two lasers at λ1 = 852.1nm and λ2=510 nm, the Cs atoms are excited to high Rydberg states via a two-step process. The Stark effect of the Rydberg Cs atom has been experimentally studied in the range of external field 0~600 V/cm, the map of the Stark spectra reveal profound “l-mixing” and “n-mixing” of the Stark sublevels.%利用原子束装置,采用双束波长为λl=852.1 nm和λ2=510 nm激光的两步激发, 实验研究了Cs Rydberg态原子在外加电场为0~600V/cm时的Stark扇形图,观察到在外电 场的作用下能级出现ι混合和n混合的现象.

  11. Ocean dynamic processes causing spatially heterogeneous distribution of sedimentary caesium-137 massively released from the Fukushima Dai-ichi Nuclear Power Plant

    Science.gov (United States)

    Higashi, H.; Morino, Y.; Furuichi, N.; Ohara, T.

    2015-08-01

    Massive amounts of anthropogenic radiocaesium 137Cs that was released into the environment by the Fukushima Dai-ichi Nuclear Power Plant accident on March 2011 are widely known to have extensively migrated to Pacific oceanic sediment off of east Japan. Several recent reports have stated that the sedimentary 137Cs is now stable with a remarkably heterogeneous distribution. The present study elucidates ocean dynamic processes causing this heterogeneous sedimentary 137Cs distribution in and around the shelf off Fukushima and adjacent prefectures. We performed a numerical simulation of oceanic 137Cs behaviour for about 10 months after the accident, using a comprehensive dynamic model involving advection-diffusion transport in seawater, adsorption and desorption to and from particulate matter, sedimentation and suspension on and from the bottom, and vertical diffusion transport in the sediment. A notable simulated result was that the sedimentary 137Cs significantly accumulated in a swath just offshore of the shelf break (along the 50-100 m isobath) as in recent observations, although the seabed in the entire simulation domain was assumed to have ideal properties such as identical bulk density, uniform porosity, and aggregation of particles with a single grain diameter. This result indicated that the heterogeneous sedimentary 137Cs distribution was not necessarily a result of the spatial distribution of 137Cs sediment adsorptivity. The present simulation suggests that the shape of the swath is mainly associated with spatiotemporal variation between bottom shear stress in the shallow shelf (< 50 m depths) and that offshore of the shelf break. In a large part of the shallow shelf, the simulation indicated that strong bottom friction suspending particulate matter from the seabed frequently occurred via a periodic spring tide about every 2 weeks and via occasional strong wind. The sedimentary 137Cs thereby could hardly stay on the surface of the seabed with the result that the simulated sediment-surface 137Cs activity tended to decrease steadily for a long term after the initial 137Cs migration. By contrast, in the offshore region, neither the spring tide nor the strong wind caused bottom disturbance. Hence, the particulate matter incorporated with 137Cs, which was horizontally transported from the adjacent shallow shelf, readily settled and remained on the surface of the sediment just offshore of the shelf break. The present simulation also clearly demonstrated that the bottom disturbance influenced the sedimentary 137Cs distributions not only horizontally but also vertically. In particular, within a part of the near-shore off the nuclear power plant, the simulation indicated that large amounts of the sedimentary 137Cs were present in both upper and deeper sediments. As a result, total sedimentary 137Cs in the entire simulation domain (1.4 x 105 km2) at the end of 2011 was 3.2 x 1015 Bq, more than 10 times that in previous estimates using samples of upper sediments.

  12. A Composite Membrane of Caesium Salt of Heteropolyacids/Quaternary Diazabicyclo-Octane Polysulfone with Poly (Tetrafluoroethylene for Intermediate Temperature Fuel Cells

    Directory of Open Access Journals (Sweden)

    Keith Scott

    2012-07-01

    Full Text Available Inorganic-organic composite electrolyte membranes were fabricated from CsXH3−XPMo12O40 (CsPOMo and quaternary diazabicyclo-octane polysulfone (QDPSU using a polytetrafluoroethylene (PTFE porous matrix for the application of intermediate temperature fuel cells. The CsPOMo/QDPSU/PTFE composite membrane was made proton conducting by using a relatively low phosphoric acid loading, which benefits the stability of the membrane conductivity and the mechanical strength. The casting method was used in order to build a thin and robust composite membrane. The resulting composite membrane films were characterised in terms of the elemental composition, membrane structure and morphology by EDX, FTIR and SEM. The proton conductivity of the membrane was 0.04 S cm−1 with a H3PO4 loading level of 1.8 PRU (amount of H3PO4 per repeat unit of polymer QDPSU. The fuel cell performance with the membrane gave a peak power density of 240 mW cm−2 at 150 °C and atmospheric pressure.

  13. Caesium hydride: MS-CASPT2 potential energy curves and A1Σ+ →X1Σ+ absorption/emission spectroscopy

    Science.gov (United States)

    Škoviera, Ján; Neogrády, Pavel; Louis, Florent; PitoÅák, Michal; Černušák, Ivan

    2017-03-01

    Correlated ab initio methods (CASPT2 and CCSD(T)) in conjunction with the ANO-RCC basis sets were used to calculate potential energy curves (PECs) of the ground, valence, and Rydberg electronic states of CsH with the inclusion of the scalar relativistic effects. The spectroscopic constants of bound states were calculated from the PECs and compared with previous theoretical and/or available experimental data. Absorption and emission spectra arising from the transition between X1Σ+ and A1Σ+ states were modelled using vibrational and rotational energy levels and corresponding nuclear wave functions obtained via the direct numerical integration of one-dimensional rovibrational Schrödinger equation in the CASPT2/ANO-RCC electronic potentials. The anharmonic shape of the A1Σ+ potential and the shape of the pertinent vibrational wave functions have an interesting impact on the final shape of the spectrum and result in the complicated fine structure of individual emission bands.

  14. OBSERVING OF RADIOACTIVE CAESIUM 137Cs VALUE IN BEEF MEAT (CZECH PIED CATTLE IN LESS-FAVOURED AREAS OF THE CZECH REPUBLIC

    Directory of Open Access Journals (Sweden)

    Ivan Holko

    2012-02-01

    Full Text Available Value of radiocaesium 137Cs as one of Risk Factors in beef meat is very important for human health. Beef meat (m. longissimus lumborum et thoracis from Czech Pied cattle in two less-favoured areas located more then 500 meters above sea level (Bohemian Forest Bohemian and Moravian Highland was dependent on Sex (decrease by female, increase by male, P<1.10-6 and on area (P<1.10-6. Value of radiocaesium 137Cs in beef meat ( = 0,42 Bq.kg-1; sx = 0,28 was less then food standard (600 Bq.kg-1. This observed result are responding to finding another authors and could be used for next more detailed research in optimal utilization of Czech Pied cattle in less-favoured areas.

  15. Poly[μ3-aqua-aqua(μ3-3,5-dinitrobenzoato-κO1:O3:O5caesium

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2012-10-01

    Full Text Available In the structure of the title complex, [Cs(C7H3N2O6(H2O2]n, the Cs salt of 3,5-dinitrobenzoic acid, the metal complex centres have have irregular CsO8 coordination, comprising two water molecules (one triply bridging and the other monodentate and four O-atom donors from two nitro groups and one bridging carboxylate O-atom donor from the ligand. Intra-unit O—H...O hydrogen-bonding interactions involving both water molecules are observed in the three-dimensional polymeric complex structure.

  16. Alternative solutions to caesium in negative-ion sources: a study of negative-ion surface production on diamond in H2/D2 plasmas

    Science.gov (United States)

    Cartry, Gilles; Kogut, Dmitry; Achkasov, Kostiantyn; Layet, Jean-Marc; Farley, Thomas; Gicquel, Alix; Achard, Jocelyn; Brinza, Ovidiu; Bieber, Thomas; Khemliche, Hocine; Roncin, Philippe; Simonin, Alain

    2017-02-01

    This paper deals with a study of H‑/D‑ negative ion surface production on diamond in low pressure H2/D2 plasmas. A sample placed in the plasma is negatively biased with respect to plasma potential. Upon positive ion impacts on the sample, some negative ions are formed and detected according to their mass and energy by a mass spectrometer placed in front of the sample. The experimental methods developed to study negative ion surface production and obtain negative ion energy and angle distribution functions are first presented. Different diamond materials ranging from nanocrystalline to single crystal layers, either doped with boron or intrinsic, are then investigated and compared with graphite. The negative ion yields obtained are presented as a function of different experimental parameters such as the exposure time, the sample bias which determines the positive ion impact energy and the sample surface temperature. It is concluded from these experiments that the electronic properties of diamond materials, among them the negative electron affinity, seem to be favourable for negative-ion surface production. However, the negative ion yield decreases with the plasma induced defect density.

  17. Caesium-137 in sandy sediments of the River Loire (FR): Assessment of an alluvial island evolving over the last 50 years

    Energy Technology Data Exchange (ETDEWEB)

    Detriche, Sebastien; Rodrigues, Stephane; Macaire, Jean-Jacques; Breheret, Jean-Gabriel; Bakyono, Jean-Paul [Universite Francois-Rabelais de Tours, CNRS/INSU UMR 6113 ISTO, Universite d' Orleans Faculte des Sciences et Techniques, Laboratoire de Geologie des Environnements Aquatiques Continentaux, Parc de Grandmont, 37200 Tours (France); Bonte, Philippe [UMR CNRS-CEA 1572, Laboratoire des Sciences du Climat et de l' Environnement - LSCE, CNRS, Domaine du CNRS, Bat. 12, 91198 Gif-sur-Yvette (France); Juge, Philippe [CETU-Elmis ingenieries, Antenne Universitaire en Val de Vienne, 11 quai Danton, 37500 Chinon (France)

    2010-07-01

    Recent sedimentological and morphological evolution of an island in the River Loire (FR) was investigated using the {sup 137}Cs method. This study describes the morphological adjustment of the island in the last 50 years, which corresponds to the increased bed incision of this sandy, multiple-channel environment because of, among other things, the increase in sediment extraction up to 1995. The results show that some {sup 137}Cs can be retained by sandy particles, potentially in clay minerals forming weathering features included in detrital sand grains. From a morphological perspective, significant lateral erosion can be observed in the upstream part of the island, while a weak lateral accretion occurs in its downstream section. Data about {sup 137}Cs and aerial photographs show that the morphology of the island margins has undergone significant changes leading to a lateral migration, while the centre of the island has remained relatively stable or is slowly eroding. The migration of the island depends on: (1) the withdrawal of inherited pre-incision morphological units, such as levees, or the development of new units, such as a channel shelf; (2) water and sediment supply from surrounding channels during flood events; (3) preferential sediment trapping (20 mm year{sup -1}) from the presence of riparian vegetation on the bank of the secondary channel that is subject to narrowing. The sedimentological and morphological response of the island in the context of incision of the Loire river bed is expressed mainly by lateral migration and secondarily by a low vertical adjustment. (authors)

  18. Accumulation of 137Cs in the European Sea Bass Dicentrarchus Labrax (L.) in a salinity gradient: Importance of uptake via gills, diet and ingested water

    OpenAIRE

    Hattink, J.; Celis, N.; De Boeck, G.; Krijger, G.C.; Blust, R.

    2009-01-01

    Radio-caesium is an important radionuclide released considering food and feed products. In aquatic environments caesium tends to accumulate in fish, both through its diet and its gills. This presentation discusses the caesium accumulation in fish living in estuaries. The aim of this work is to conclude on the importance of potential uptake routes: via the gills, diet or ingested with water. It is suggested that the magnitude of caesium accumulation in fish is related to waterborne potassium c...

  19. Cesium 137 and cesium 134 in roe deer from the north and central Hessen area: Measurement of the contamination in muscle tissue after the Chernobyl accident. Caesium 137 und Caesium 134 in Rehwild aus Nord- und Mittelhessen: Untersuchungen zur Kontamination von Muskelgewebe nach dem Reaktorunfall in Tschernobyl

    Energy Technology Data Exchange (ETDEWEB)

    Georgii, S.; Brunn, H.; Eskens, U. (Staatliches Medizinal-, Lebensmittel- und Veterinaeruntersuchungsamt Mittelhessen, Giessen (Germany, F.R.))

    1989-06-01

    The present report describes the amount of incorporated 134 and 137 cesium in the muscle tissue of 330 roe deer, which were referred for routine necropsy between 1986 and 1988. The amount of incorporated radiocesium was markedly decreased in 1987 and 1988 compared with 1986. However, a seasonal fluctuation with increase of the measured incorporated radioactivity during the autumn months was observed in 1987 and 1988. (orig.).

  20. Non cancerous diseases following a chronic intern contamination by caesium 137: cataracts and cardiac arrhythmias; Pathologies non cancereuses potentiellement consecutives a une contamination interne chronique par le cesium 137: cataractes et arythmies cardiaques

    Energy Technology Data Exchange (ETDEWEB)

    Landon, G

    2008-07-15

    This work of thesis joins within the framework of an analysis of the sanitary consequences of the nuclear accident of Chernobylsk. Since 2005, the I.R.S.N. is interested in the not cancerous pathologies (cataracts, and cardiac arrhythmias) observed among the children living on the contaminated territories after the fallout of Chernobylsk and has in this aim implemented a research programme called E.P.I.C.E. (Evaluation of the pathologies induced by a chronicle contamination by cesium) whom objective is to show an eventual link between the chronicle ingestion of contaminated food and these pathologies emergence. An exploitation of the results of the pilot study,first phase of the E.P.I.C.E. program was realized. The analysis was completed by two bibliographical reviews relative to the knowledge available on these diseases. The results of this pilot study suggest: on one hand, an absence of link between the activity in cesium 137 at the level of the heart, of the whole body and the emergence of disorder of the heart rhythm; on the other hand, for the cases of cataract, a link between the load in cesium 137 at the neck level and the emergence of the disease in 40 % of the cases. However, these results must be considered with caution because several limits and, in particular, a way of selection affect this study. concerning the scientific literature, this one stays rather poor because only thee articles make reference to a relationship between cesium 137 and the emergence of these non cancerous pathologies. After having exposed the context, this thesis draws up the situation of knowledge relative to cataracts and to cardiac arrhythmias and their possible relationship with ionizing radiations, collect the results stemming from the analysis of the pilot study and envisages future epidemiological studies. (N.C.)

  1. Dispersal of the radionuclide caesium-137 ((137)Cs) from point sources in the Barents and Norwegian Seas and its potential contamination of the Arctic marine food chain: coupling numerical ocean models with geographical fish distribution data.

    Science.gov (United States)

    Heldal, Hilde Elise; Vikebø, Frode; Johansen, Geir Odd

    2013-09-01

    Dispersal of (137)Cs from the nuclear submarine wrecks Komsomolets and K-159, which are resting on the seabed in the Norwegian and Barents Seas, respectively, is simulated using realistic rates and hypothetical scenarios. Furthermore, spatiotemporal (137)Cs concentrations in Northeast Arctic cod and capelin are estimated based on survey data. The results indicate that neither continuous leakages nor pulse discharges will cause concentrations of (137)Cs in cod muscle or whole body capelin exceeding the intervention level of 600 Bq/kg fw. Continuous leakages from Komsomolets and K-159 and pulse discharges from Komsomolets induced negligible activity concentrations in cod and capelin. A pulse discharge of 100% of the (137)Cs-inventory of K-159 will, however, result in concentrations in muscle of cod of above 100 times the present levels in the eastern Barents Sea. Within three years after the release, (137)Cs levels above 20 Bq/kg fw in cod are no longer occurring in the Barents Sea.

  2. Development, control and counter-measures regarding radioactive caesium in Swedish reindeer after the Chernobyl accident; Utveckling, oevervakning och aatgaerder naer det gaeller radioaktivt cesium i renar efter Tjernobylolyckan

    Energy Technology Data Exchange (ETDEWEB)

    Aahman, Birgitta [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Reindeer Husbandry Unit

    2005-10-01

    Since the Chernobyl accident in 1986, monitoring of {sup 137}Cs in reindeer has been made at slaughter, by measuring muscle samples or by direct monitoring of gamma radiation on reindeer carcasses. Carcasses above the accepted limit have been discarded. Many carcasses were discarded during the first years, but now the number is only some per cent of the total slaughter. The radiocaesium intake in reindeer varies with season, which is reflected in the levels in reindeer, which are low in summer and high in winter. The levels of {sup 137}Cs have declined from 1986 to 2004 with an average effective half-life of 5.3 years. The decline was faster during the first years than during later years. Presently, 16 out of totally 51 reindeer herding districts in Sweden are included in the control of {sup 137}Cs in reindeer. Control is often necessary only in defined areas or at certain periods of the year. Monitoring of {sup 137}Cs in live reindeer is made in addition to the monitoring at slaughter. Counter-measures have been applied in areas where many reindeer are above the accepted limit for {sup 137}Cs. Change of slaughter time and feeding are the most used counter-measures. The reindeer owners are compensated economically from the state for costs related to these counter-measures. The need for measures, and thereby the costs, have decreased with time. In the southern parts of the county of Vaesterbotten and in the northernmost part of Jaemtland, where the Chernobyl fallout was the highest, it will probably still take at least ten to twenty years until measures and control are no longer needed.

  3. Investigations into the transfer of cesium 137 and strontium 90 in selected exposure pathways. Final report; Untersuchungen ueber den Transfer von Caesium 137 und Strontium 90 in ausgewaehlten Belastungspfaden. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Roemmelt, R.; Hiersche, L.; Wirth, E.

    1991-12-01

    This research project investigates the behaviour of radiocesium and strontium 90 in natural conifer forest sites and derives corresponding transfer factors for radioecological calculations. As a point of particular interest the question was investigated in how far the requirements of the different mushroom species and the properties of the forest soil bear on the dynamics and transfer rate of radiocesium and strontium 90. To complement the investigations, autotrophic plants were included. The results of these studies are compared with the behaviour of the same radionuclides on farmland. The differences are discussed. (orig./HP). [Deutsch] Im Forschungsvorhaben wurde das Verhalten von Radiocaesium und Strontium 90 in den natuerlichen Nadelstandorten untersucht und entsprechende Transferfaktoren fuer radiooekologische Berechnungen abgeleitet. Besondere Aufmerksamkeit galt der Frage, inwieweit die Lebensweise der verschiedenen Pilzspezies und die Waldbodeneigenschaften die Dynamik und die Transferrate von Radiocaesium und Strontium 90 beeinflussen. Als Ergaenzung wurden autotrophe Pflanzen in die Untersuchungen einbezogen. Die Ergebnisse dieser Untersuchungen werden mit dem Verhalten dieser Radionuklide auf landwirtschaftlich genutzten Flaechen verglichen und die Unterschiede diskutiert. (orig./HP).

  4. In-vivo determination of strontium 90 and cesium 137 in exposed persons in the Tscheljabinsk region (southern Ural); In-vivo-Bestimmung von Strontium 90 und Caesium 137 an exponierten Personen in der Region Tscheljabinsk (Suedural)

    Energy Technology Data Exchange (ETDEWEB)

    Schoeffmann, E. [Bayerisches Landesamt fuer Umweltschutz, Muenchen (Germany). Referat Betrieb der LfU-Messnetzzentrale; Zeising, H. [Bayerisches Landesamt fuer Umweltschutz, Muenchen (Germany). Referat Radioaktivitaetsmesswesen

    1994-12-31

    While the Russians have been busy for decades determining the doses received by, and resulting health effects to, the concerned population - which falls into three groups: (a) workers at the Majak plutonium factory, (b) the population along the Techa river, and (c) the population from the area contaminated by the Kyschtym accident - it is also true that the integral strontium 90 exposure has been, and is being, determined subsequently via whole-body bremsstrahlung measurement (both on the part of the Russians and as a German scheme in 1993). In accordance with what was indicated by the Russian side, the Majak workers were found to have a distinctly higher risk of cancer. The population along the Techa river, too, with an average dose of 0.4 Gy for the red bone marrow, showed a significant increase in the rate of leukemia. By contrast, the persons affected by the Kyschtym accident, with a distinctly lower mean dose of about 0.02 Gy, so far have not shown any long-term effects.- As yet no exact quantitative statement regarding the cancer risks can be made, for two reasons: the comprehensive data material collected by the Russians has not yet been sufficiently evaluated, and suitable control persons need yet to be found. (orig./HP) [Deutsch] An einer Bestimmung der Dosen und der daraus resultierenden gesundheitlichen Effekte der betroffenen Bevoelkerung - naemlich der drei Gruppen (a) Arbeiter der Plutoniumfabrik Majak, (b) die Bevoelkerung entlang des Flusses Techa und (c) die Bevoelkerung aus dem durch den Kyschtym-Unfall kontaminierten Gebiet, wird zwar von russischer Seite seit Jahrzehnten gearbeitet, aber die integrale Sr 90-Exposition wurde und wird nachtraeglich ueber die Messung von Bremsstrahlung im Ganzkoerper (neben russischer Messung auch die deutsche Messaktion im Jahre 1993) bestimmt. Wie von russischer Seite angegeben, fand sich bei den Majak-Arbeitern eine deutliche Erhoehung des Krebsrisikos, ebenso wurde bei der Bevoelkerungsgruppe entlang des Flusses Techa mit einer durchschnittlichen Dosis von 0,4 Gy fuer das rote Knochenmark eine signifikante Erhoehung der Leukaemierate festgestellt. Bei den durch den Kyschtym-Unfall betroffenen Personen mit einer deutlich niedrigeren mittleren Dosis von ca. 0,02 Gy wurden bisher dagegen keine Langzeiteffekte festgestellt. Eine genaue quantitative Aussage zu den Krebsrisiken kann vorerst noch nicht gegeben werden, da zum einen das von russischer Seite gesammelte umfangreiche Datenmaterial noch nicht ausreichend ausgewertet ist und zum anderen noch geeignete Kontrollpersonen gefunden werden muessen. (orig./HP)

  5. Long-lived fission products 90 Sr and 137 Cs from nuclear weapons test fallout and their distribution in the soil. Die Verteilung der langlebigen Spaltprodukte Strontium 90 und Caesium 137 des Kernwaffen-Fallouts im Boden

    Energy Technology Data Exchange (ETDEWEB)

    Gans, I.; Arndt, J.

    1987-01-01

    For this study, samples have been taken down to a depth of 1.30 m, in five sandy soils, three cohesive soils, and one shallow moor. In undisturbed sandy soils, most of the 137 Cs is still near the surface, the mean depth of penetration being between 1.7 and 4.7 cm, so that transport velocities of 0.1 up to 0.3 cm/a are derived for humous upper soil layers. 90 Sr has been detected up to a depth of 1.30 m at some places. As the overall amount of 90 Sr found in the samples has been less than 50% of the amount to be expected from fallout data it is assumed that the missing amount migration to lower strata. The transport velocities derived for 90 Sr in humous upper soil layers are about 1 cm/a, and at least 5 cm/a in the sandy soil layers at greater depths. The distribution coefficients for 90 Sr in humous upper soil layers are 10 cm/sup 3//g and max. 1 cm/sup 3/ in depper sandy soils strata. Due to small depth of penetration of 137 Cs, a distribution coefficient can be assessed only for humous upper soil layers, and is about 100 cm/sup 3//g. Transport velocities assessed for 90 Sr in cohesive soils are about 1 cm/a and thus about the same as in humous upper soil layers of sandy soil. For 137 Cs, only upper limits of 0.02 up to 0.1 cm/a can be given. So the distribution coefficients for 90 Sr assessed to be between 1 and 25 cm/sup 3//g are within the same range as those for humous soils, and for 137 Cs are more than 100 cm/sup 3//g. In shallow moor, the distribution coefficients for 137 Cs and 90 Sr are about the same with about 5 cm/sup 3//g. (orig./HP) With 9 figs., 29 tabs.

  6. Evolution of caesium 137 levels in coconut water and copra in french Polynesia, since 1967. Evolution de la teneur en cesium 137 depuis 1967 dans l'eau de coco et le coprah en Polynesie francaise

    Energy Technology Data Exchange (ETDEWEB)

    Kabis de Saint-Chamas, L.; Bablet, J.P.; Ducousso, R. (Service mixte de controle biologique, 91 - Montlhery (FR)); Arnould, C. (Laboratoire d' etude et de surveillance de l' environnement, Papeete (FR))

    1991-01-01

    Nuclear experiments have been carried out by France in french Polynesia since 1966. The tests were first atmospheric, they have been underground since 1975. The experiment monitoring programme includes monitoring of {sup 137}Cs contents in coconuts from the whole french polynesian territory. The methodology is described and the results of the 2 589 samples collected for 1967 to 1988 are presented. The maximum content found since 1967 is 52 Bq.kg{sup -1} for coconut water and 289 Bq.kg{sup -1} for coconut copra. The decrease of {sup 137}Cs content is constant without discontinuity, whatever the distance from the explosion sites. The committed dose equivalent from {sup 137}Cs delivered by coconut water and copra consumption represents only a few microsieverts a year.

  7. Study on Adsorptive Property of Clay for Strontium and Caesium%Sr~(2+)、Cs~+在粘土中的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    叶正中; 易发成

    2011-01-01

    采用间歇法研究在不同实验条件下(浓度、固液比、粒径、pH),选用的粘土对Sr2+、Cs+的吸附性能。实验结果表明:室温条件下,Sr2+、Cs+溶液浓度和固液比对红粘土的吸附性能影响较大;红粘土对Cs+的吸附性能优于对Sr2+的吸附性能,当浓度为10 mg/L时,粘土对Cs+的吸附效率可达88%。%An intermittence method was adopted to study the adsorption of clay for Sr2+(strontium) and Cs+(caesium) under various conditions including different concentration,solid-to-liquid ratio,adsorbent size and pH value.The results showed that adsorptive capacity depended on the concentration and solid-to-liquid ratio at room temperature.The absorption of clay for Sr2+ was better than that for Cs+.When the concentration was 10 mg/L,the remove rate of clay for Cs+ was 88%.

  8. APPLICATION OF THE CAESIUM-137 TECHNIQUE ON WIND EROSION IN THE GONGHE BASIN, QINGHAI PROVINCE%青海共和盆地土壤风蚀的137Cs法研究

    Institute of Scientific and Technical Information of China (English)

    严平; 董光荣

    2003-01-01

    选择青海共和盆地作为研究区,探讨137Cs法在土壤风蚀研究中应用的可行性.通过野外考察和大量的137Cs取样分析,初步查明了共和盆地不同类型地表的137Cs含量及其剖面分布,确定了区域137Cs背景值为2 691.78±196.08 Bq m-2,建立了风蚀速率的137Cs评估模型,估算出四个样方的土壤风蚀速率,并由此转化为区域风蚀速率,计算出共和盆地区域土壤风蚀速率为12.556 t hm-2 a-1,通过蚀积平衡检验,其误差水平小于10%.

  9. 不同产地的沸石对核素Cs+的吸附特性研究%Study on Adsorption Performance of Zeolite from Different Mining Area for Caesium

    Institute of Scientific and Technical Information of China (English)

    王哲; 刘雪婷

    2015-01-01

    采用静态吸附实验方法,研究了吸附时间、溶液pH值、吸附剂加入量和溶液初始浓度等因素下,新疆沸石、缙云沸石及赤峰沸石对Cs+吸附性能,结果表明:在处理较低浓度的含Cs+废液时,新疆沸石和缙云沸石对放射性核素Cs+的吸附性能差别不大,并且两者的吸附性能明显优于赤峰沸石对Cs+吸附效果;在处理较高浓度的含Cs+废液时,新疆沸石对放射性核素Cs+吸附性能最优于缙云沸石,而赤峰沸石对Cs+的处理效果最差.因此,新疆沸石较适宜处理不同浓度的含Cs+放射性废水,该研究结果可为放射性废水处理、高放废物地质处置库中的人工屏障设计及集成缓冲材料开发提供科学依据.

  10. CAESIUM-137 ACCUMULATION BY HALOPHYTES AT A RADIONUCLIDE CONTAMINATED SITE%某放射性污染区盐生植物对137Cs的吸收研究

    Institute of Scientific and Technical Information of China (English)

    唐秀欢; 潘孝兵; 万俊生; 刘月恒; 杨永青

    2008-01-01

    植物修复技术适用于大面积、低活度的放射性污染治理,在一些大面积放射性污染区具有潜在的应用前景.本研究在某放射性典型污染区域取样,测量了该区域盐生植物及其生长土壤的137Cs含量,以生物富集系数(BC值)为指标,分析了不同核素土壤分布、K元素含量等因素对BC值的影响.研究结果表明,污染区植物对137Cs的吸收BC值在10-5~10-2数量级之间,多数区域由于核素分布不均匀而引起BC值下降,均匀分布则有利于核素的吸收.另外,BC值还与土壤K元素含量呈负相关.

  11. 长江上游云贵高原区泥沙来源的137Cs法研究%Study on Sedimentation Source Using Caesium-137 Technique in Yungui Plateau Region of Upper Yangtze River

    Institute of Scientific and Technical Information of China (English)

    文安邦; 张信宝; 王玉宽; 王建文; 贺廷荣; 张一云; 徐家云; 白立新

    2000-01-01

    通过云贵高原区龙川江流域不同源地表层土壤和坝库淤积泥沙137Cs含量的对比,结合流域土地利用现状,分析了4个不同土地利用类型小流域相对来沙量,结果表明,侵蚀裸坡和沟道重力侵蚀是坝库淤积泥沙的主要来源,随着流域面积增大,相对产沙量为54%~85%.

  12. Separation of Cs -137 from Reactor Sediment Through Precipitation of Caesium Phosphotungstate%磷钨酸铯沉淀法分离反应堆底泥中的137Cs

    Institute of Scientific and Technical Information of China (English)

    徐伟强; 丁兴成

    2004-01-01

    在酸性体系中,利用磷钨酸与铯反应产生沉淀来分离反应堆底泥中的137Cs,实验结果表明:该方法比较简单,一次沉淀即可将137Cs与其它放射性核素有效分离,铯的回收率为99.72%,其它α核素对铯的玷污率为5%以下,实现了铯与其它放射性核素分离的目的,其它核素的去污率大于98%.

  13. 137Cs示踪农耕地土壤侵蚀速率模型的比较研究%THE DISCUSSION ON MODELS FOR ESTIMATING SOIL EROSION RATES FROM CAESIUM-137 MEASUREMENTS ON CULTIVATED LAND

    Institute of Scientific and Technical Information of China (English)

    李立青; 杨明义; 刘普灵; 王晓燕; 田均良

    2004-01-01

    137Cs示踪技术广泛地应用于农耕地土壤侵蚀研究,目前已建立了许多运用137Cs估算土壤侵蚀速率的模型.这些模型主要分为两类:经验模型与理论模型.其中理论模型中的质量平衡模型应用较多.质量平衡模型主要有:Walling模型、张信宝模型、杨浩模型和周维芝模型.重点讨论这4种质量平衡模型的异同.详细阐述了这四种模型的建立过程,并用图形模拟的方法给出各个模型所刻画的土壤侵蚀速率与土壤剖面中137Cs相对损失率的关系.分析表明,尽管各个模型在建立的假设和方法上以及对137Cs沉降过程的处理上存在一定程度的差异,但是各个模型所刻画的土壤侵蚀速率与土壤剖面中137Cs相对损失率的关系实质上都是幂函数的形式,而且这4条曲线的走势基本一致,各自计算的土壤侵蚀速率差异也较小.因此,在利用137Cs技术示踪农耕地土壤侵蚀速率时,这4个模型都可以应用.

  14. QUANTITATIVE MODEL TO ESTIMATE SOIL EROSION RATES USING CAESIUM-137 FOR CULTIVATED SOIL%利用137Cs示踪农业耕作土壤侵蚀速率的定量模型

    Institute of Scientific and Technical Information of China (English)

    杨浩; 杜明远; 赵其国; 阳捷行; 八田珠郎

    2000-01-01

    建立了一个根据农业耕作土壤剖面中137Cs的损失量与土壤侵蚀量之间关系的定量模型.在假设137Cs在耕层中得到充分的混合而变得均一的基础上,根据质量平衡模型推导而成.模型显示137Cs的衰变常数,年沉降分量,耕层厚度和采样年份对年平均土壤侵蚀速率都有重大影响.模型结果还说明,137Cs的损失量与年平均土壤侵蚀量之间的关系既非线性关系亦非指数关系,而是一种复杂的曲线关系.

  15. 利用壳状地衣监测陆地环境中137Cs活度浓度的研究%Research on Monitoring Caesium - 137 Radiation Level of Land Environment by Crustaceous Lichens

    Institute of Scientific and Technical Information of China (English)

    杜春光; 张京; 李文红; 徐翠华; 赵烨

    2005-01-01

    目的比较壳状地衣与其他环境样品中137Cs活度浓度差异,分析壳状地衣作为敏感的生物指示剂监测陆地环境中137Cs活度浓度的可行性.方法运用美国0RTEC公司生产的ADCAM-100超低本底γ谱仪对样品进行137Cs测定,其探测器为高纯锗同轴探测器.结果壳状地衣体中137Cs活度浓度值比土壤表层中的137Cs活度浓度值高出一个数量级,比粮食、蔬菜、水果和蛋奶肉品中137Cs活度浓度值高出三个以上数量级.结论壳状地衣具有分布广泛、生长周期长、通过其表面积从大气中吸附获取营养物质等特征,因此,壳状地衣是监测环境中137Cs核素远距离传输及其活度水平的敏感指示剂.

  16. Purification of enterocin E9 from the cultivation supernatant of Enterococcus caesium by SPE/HPLC%屎肠球菌细菌素Enterocin E9 SPE/HPLC分离纯化方法的建立

    Institute of Scientific and Technical Information of China (English)

    鲍宇晖; 张永红; 王建舫; 李佳; 崔德凤; 马梦; 王惠川

    2014-01-01

    为了获得单一的细菌素Enterocin E9成分,使其发挥最大抑菌活性,建立在线SPE/HPLC分离Enterocin E9的方法.通过细菌培养,上清液收集、浓缩,获得细菌素粗提样品,采用Sepbox 2D-250全自动二维液相分离系统,确认流动相组成,流速和洗脱时间等因素.提取的单一成分其抑菌效果是浓缩样品的2.4倍.该方法省时、省力、精密度高,为细菌素结构与功能的研究提供一条有效途径和方法.

  17. Accumulation and physio-biochemical responses of Salix paraplesia to caesium stress%康定柳对铯胁迫的生理生化响应及富集能力

    Institute of Scientific and Technical Information of China (English)

    朱靖; 陈珂; 张渊; 杨叶

    2016-01-01

    主要探讨康定柳(Salix paraplesia)在水培条件下对铯胁迫(133Cs+浓度0、50和200 μmol/L)的生理生化响应和富集修复能力.研究结果表明:铯胁迫造成了植物的过氧化损伤,且与胁迫浓度呈正相关;植物通过提高渗透调节能力(Pro)和抗氧化能力(SOD、POD和CAT)应对铯胁迫,但高浓度铯胁迫却显著抑制了植株抗氧化系统的作用.从植物光合荧光指标和叶绿素含量来看,低浓度铯能促进植物叶绿素合成且对光合能力影响不大,而高浓度铯胁迫则抑制了植物叶绿素的合成及光合能力.此外,与对照相比,低浓度铯胁迫能够显著促进植株的茎长,而高浓度铯胁迫则显著抑制了植株的生物量、根长和茎长,对植株生长发育的抑制作用明显.康定柳对水体中铯的富集量和富集系数均表现为根>茎>叶,铯主要富集在植株根部,且在高处理浓度下,植株富集量最高达到2.235 8 mg/g DW.表明康定柳对水体中铯的污染具有较好的耐受性和修复潜力.

  18. 生物样品中铯-137活度浓度的两种分析方法比较%The Comparison of Two Different Methods of Analysing Specific Activity of Caesium-137 in Biological Samples

    Institute of Scientific and Technical Information of China (English)

    吕魁; 黄福琴; 黄淑琳

    2007-01-01

    目的 探讨生物样品中铯-137活度浓度的γ能谱法与放射化学法分析结果的一致性.方法 对多种生物样品分别用这两种方法进行比对测量,并对结果进行统计检验和线性拟合.结果 两种方法的实验结果没有显著性差别,并且线性相关. 结论 两种方法可视工作需要相互替代.

  19. Study on Adsorptive Property of XJ Bentonite for Strontium and Caesium%新疆膨润土对Sr~(2+)、Cs~+的吸附性能的研究

    Institute of Scientific and Technical Information of China (English)

    李宁波; 易发成

    2009-01-01

    An intermittence method was adopted to study the adsorption of XJ bentonite (XJ for short) for Sr~(2+) and Cs~+ under various conditions including different concentration, solid-to-liquid ratio ,temperature, pH value and groundwaters. The results show that adsorptive capacity of XJ for Sr~(2+) and Cs~(2+) is high with adsorptive equilibrium time of 7 days and equilibrium adsorptive quantities were 40mg/g and 129mg/g when Sr~(2+) and Cs~+concentrations are 0.01mol/L. Adsorptive capacity firstly depends on the solution concentration and solid-to-liquid ratio, secondly on the grotmdwatera, pH value and temperature of the solution.%采用间歇法研究在不同环境条下(浓度、固液比、温度、pH值、介质),新疆膨润土(简称XJ)对Sr~(2+)、Cs~+'的吸附性能影响.结果表明:XJ对Sr~(2+)、Cs~+的吸附性能比较好,当Sr~(2+)、Cs~+浓度为0.01mol/L时,XJ对Sr~(2+)、Cs~+的吸附平衡时间约在7天左右,平衡吸附量分别为40mg/g、129mg/g.Sr~(2+)、Cs~+的浓度和不同固液比对XJ的吸附性能影响比较大,其次是不同介质、溶液的pH值和溶液的温度.

  20. Study on Adsorption Performance of GMZ Bentonite from Neimeng Province for Radioactive Strontium and Caesium%内蒙高庙子膨润土对放射性核素锶和铯的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    王哲; 李海峰

    2015-01-01

    采用静态吸附实验方法,研究了吸附时间、溶液pH值、吸附剂投加量和溶液初始浓度等因素对内蒙高庙子膨润土吸附Sr2+和Cs+的性能,结果表明:高庙子膨润土对含Cs+放射性废水的处理效果要优于对含Sr2+的处理效果,其原因在于Cs+离子水合半径比Sr2+的离子水合离子小,当Sr2+和Cs+与蒙脱石矿物层间Na+、K+、Ca2+和Mg2+等发生离子交换时,Cs+离比Sr2+离子更易于进入蒙脱石层间而被固定.

  1. Solution Heat of Potassium Styphnate and Caesium Styphnate in Water and DMF at 298.15 K%298.15 K时斯蒂芬酸钾盐和铯盐在水和DMF中的溶解热

    Institute of Scientific and Technical Information of China (English)

    刘影; 佟文超; 杨利; 张同来; 冯长根

    2013-01-01

    The dissolution and thermochemical properties of potassium styphnate [K2(TNR) (H2O)]n and cesium styphnate [Cs2(TNR)(H2O)2]n in water and N,N-dimethylformamide (DMF) at 298.15 K were studied by calorimetry. The processes are endothermic in water, and exothermic in DMF because of the different molecular structure and polarity of the solutes and solvents. Empirical formulas for the solution enthalpies (ΔsolH), relative apparent molar solution enthalpies (ФLi), relative partial molar enthalpies (Li), and dilution enthalpies (ΔdilH1,2) are deduced by polynomial expressions, and standard solution enthalpies (ΔsolHm) are also calculated.%  在298.15 K时,采用微热量热仪测定斯蒂芬酸钾盐[K2(TNR)(H2O)]n和斯蒂芬酸铯盐[Cs2(TNR)(H2O)2]n两种含能配合物在水和N,N-二甲基甲酰胺(DMF)溶剂中的溶解热,研究其溶解过程和溶解热化学性质.结果表明,两种配合物溶解于水是吸热过程,而溶解于DMF则为放热过程,这主要是由于溶质和溶剂的分子结构及其极性不同而导致的.通过对实验数据计算拟合,求得这两种配合物的溶解焓(ΔsolH)、相对表观摩尔焓(ФLi)、相对偏摩尔焓(Li)及稀释焓(ΔdilH1,2)的经验公式和标准溶解焓值(ΔsolHm).

  2. Experimental contamination of margaritana margaritifera (L) (a Fresh water bivalve) by caesium 137; Contamination experimentale de margaritana margaritifera (L) (bivalve d'eau douce) par le cesium 137

    Energy Technology Data Exchange (ETDEWEB)

    Foulquier, L.; Bovard, P.; Grauby, A. [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1966-07-01

    The hydro biological research carried out in the Radio-Ecology Section has led the authors to study some Margaritana sampling stations situated down-stream from the Monts d'Arree nuclear power station. They describe the preservation and contamination methods used for fixing the {sup 137}Cs concentration factors in the case of Margaritana Margaritifera (L). The results of experiments carried out over a period of one hundred days show that the specific activity of the various organs is stabilized after thirty to thirty-five days. The authors have noticed a relatively low adsorption on the shell through the intermediary of micro-organisms, and a strong and rapid absorption in the soft parts. The concentration factors have values, at equilibrium, of around: 9 for the shell, 300 for all the organs, and 38 for the whole animal. A comparison of these results with work published by other authors makes it possible to draw general conclusions concerning the mechanism of {sup 137}Cs fixation by lamellibranch, as well as their capacity of fixation. (author) [French] Les etudes hydrobiologiques effectuees au sein de la Section de Radio-Ecologie ont amene les auteurs a etudier des stations de prelevement de Margaritana en aval de la Centrale Nucleaire des Monts d'Arree. Ils decrivent les methodes de conservation et de contamination utilisees pour l'etablissement des facteurs de concentration du {sup 137}Cs par Margaritana margaritifera (L). Les resultats des experimentations menees pendant cent jours montrent que les activites specifiques de la coquille et des differents organes se stabilisent au bout de trente a trente-cinq jours. Les auteurs constatent une adsorption relativement faible sur la coquille par l'intermediaire des micro-organismes et une absorption forte et rapide dans les parties molles. Les facteurs de concentration se situent, a l'equilibre, autour de: 9 pour la coquille, 300 pour l'ensemble des organes et 38 si l'on considere l'animal total. Cette etude comparee a celles deja effectuees par d'autres auteurs permet de degager des idees generales sur le mode et la capacite de fixation du {sup 137}Cs par les lamellibranches. (auteur)

  3. Probing Many-Body Interactions in an Optical Lattice Clock (Preprint)

    Science.gov (United States)

    2013-10-23

    9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine energy levels of a caesium atom. Since then, the accuracy...as meter, volt and ampere. Thanks to the development of laser trapping and cooling techniques [1, 2], the best caesium standards have reached an...accuracy of one part in 1016. However, caesium clocks are limited by the fact that they are based on atomic transitions in the microwave domain. Because

  4. Evaluation of Long Term Performance of Continuously Running Atomic Fountains

    Science.gov (United States)

    2014-05-28

    Observatory (USNO). These fountains are used as continuous clocks in the manner of commercial caesium beams and hydrogen masers for the purpose of improved...clock, rubidium fountain, operational atomic fountain (Some figures may appear in colour only in the online journal) 1. Introduction: beyond caesiums ...and masers The performance of atomic clocks has improved more than seven orders of magnitude since the first caesium clock was demonstrated by Essen

  5. Conformer of the peroxynitrite ion formed under photolysis of crystalline alkali nitrates – cis or trans?

    Science.gov (United States)

    Pak, V. Kh; Anan’ev, V. A.; Dyagileva, E. P.; Lyrshchikov, S. Yu; Miklin, M. B.; Rezvova, M. A.

    2017-01-01

    The optical and infrared reflectance spectra of the crystalline powders prepared by co-crystallization of caesium nitrate, nitrite, and peroxynitrite from alkali solution have been studied. We find that the trans conformer forms under photolysis of crystalline pure caesium nitrate. Under its dissolution the trans conformer transforms to the cis conformer.

  6. A Proof-of-concept Study on Integrating GEANT4 and MATLAB to Develop a Simulation Capability for Testing Radiological Source Localisation Algorithms

    Science.gov (United States)

    2011-02-01

    particles matching the energy distribution and relative abundances expected. For example, to model a caesium -137 source the following commands can be...must be specified as the ion; in this case we have specified the /gps/ion to be the caesium -137 isotope. The arguments of the ion command are as

  7. 16TH Nordic Semiconductor Meeting, Laugarvatn, Iceland, 12-15 June 1994. Abstracts

    Science.gov (United States)

    2007-11-02

    Vs, which is of n-type, however. Accompanying optical measurements will also be reported. - 127 - ssm2 Adsorption of Lithium, Caesium and Oxygen on a...material. Adsorption of lithium and caesium and the coadsorption of both alkali-metals and oxygen on a-Si:H surfaces were investigated by AES, XPS

  8. JPRS Report, Environmental Issues

    Science.gov (United States)

    2007-11-02

    beginning of May. If today figures are to be heard for the area contaminated with caesium -137 upwards of one curie per square kilometer amounting...benefits, according to the criteria established of 15 curies for caesium , three curies for strontium and one tenth for plutonium. You know that there are

  9. Evaluation of Light Frequency Shift in a Cesium Beam Frequency Standard with Sharp Angle Incident Detecting Laser

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-Hai; WANG Feng-Zhi; WANG Yi-Qiu; YANG Dong-Hai

    2004-01-01

    @@ Light frequency shift measured in a smalloptically pumped caesium beam frequency standard is reported and analysed. Two light sources, the diffused laser light scattered from the caesium beam tube parts and the fluorescence light from the beam atoms excited by the laser light, for the light frequency shift are discussed.

  10. Radiation Internal Monitoring by In Vivo Scanning in Operation Tomodachi

    Science.gov (United States)

    2013-08-01

    1997), which states: Systemic caesium is taken to be distributed uniformly throughout all body tissues; 10% of activity is assumed to be retained with...significantly less than for males (Publication 56, ICRP, 1990). There is also evidence that in some countries the mean biological half-time of caesium in

  11. NIST F1 and F2

    Science.gov (United States)

    2010-11-01

    2007, “Cancellation of the Collisional Frequency Shift in Caesium Fountain Clocks,” Physical Review Letters, 98, 153002. [4] W. M. Itano, L. L...R. Schröder, and R. Wynands, 2006, “Effects of microwave leakage in caesium clocks: theoretical and experimental results,” in Proceedings of the 20

  12. Collisional Dynamics, Lasing and Stimulated Raman Scattering in Optically Pumped Cesium and Potassium Vapors

    Science.gov (United States)

    2012-03-22

    J. Quant. Spect. Radiat. Trans., 16(127-135), 1976. [31] Ferray, M., J.P. Visticot, J. Lozingot, and B. Sayer. “Broadening of the caesium second...pressures”. Phys. Rev. A., 75(023401), 2007. [72] Rostas, F. and J. L. Lemaire. “Low pressure measurement of the broadening and shift of the caesium

  13. Transport processes of Cs-137 in lake environments

    Energy Technology Data Exchange (ETDEWEB)

    Hilton, J.; Carrick, T.R.; Lishman, J.P.; Rigg, E. [Inst. of Freshwater Ecology, Windermere (United Kingdom); Davison, W.; Kelly, M.; Hamilton-Taylor, J. [Lancaster Univ. (United Kingdom). Inst. of Environmental and Biological Sciences

    1992-12-31

    Radiocesium levels in the waters of the Lake District dropped after the initial deposition following the Chernobyl reactor accident. However they continued to be measurable several years after the event. Caesium 137 concentrations were measured in the sediments of Esthwaite water and Windermere to determine the input of caesium 137 from the catchment area to the lakes. Experiments were conducted to ascertain the chemical conditions such as pH value, adsorption, competing ions which might contribute to maintaining caesium levels in the lakes. (U.K.).

  14. Evolution of Timescales from Astronomy to Physical Metrology

    Science.gov (United States)

    2011-07-20

    where the duration of a second is defined not by astronomy but by an energy level transition in the caesium atom. The designation of seconds for the...calibrated the resonance frequency of the laboratory’s caesium standard with respect to the UT2 second of that epoch [16]. Together with Markowitz and...rate Moon camera over the period 1955.50 to 1958.25. The measured caesium frequency was 9 192 631 770 Hz with an uncertainty of ±20 Hz mostly due to the

  15. Observation of Query Pulse Length Dependent Ramsey Interference in Rubidium Vapor Using Pulsed Raman Excitation

    Science.gov (United States)

    2011-11-07

    Cerez, “Observation of narrow Ramsey-type resonances in a caesium beam due to Zeeman coherences,” J. Phys. B 24(13), 2957–2966 (1991). 4. B. Schuh...Parry, “An atomic standard of frequency and time interval: a caesium resonator,” Nature 176(4476), 280–282 (1955). 8. A. G. Mungall, H. Daams, and... Caesium beam frequency standards: classical and optically pumped,” Metrolog. 29(2), 113–134 (1992). 10. J. Thomas, P. R. Hemmer, S. Ezekiel, C. C. Leiby

  16. Radioactive contamination in reindeer herders and other people in Kautokeino 1965-2010; Radioaktiv forurensning i befolkningen. Reindriftsutoevere og andre personer i Kautokeino 1965-2010

    Energy Technology Data Exchange (ETDEWEB)

    Thoerring, H.; Skuterud, L.

    2012-07-01

    NRPA's measurements of radioactive caesium in reindeer herders and other people from Kautokeino in northern Norway were finalised in December 2010. This report summarises the monitoring program which was started in 1965.(Author)

  17. Propagation of a Rectangular Pulse in an Anomalous Dispersive Medium

    Institute of Scientific and Technical Information of China (English)

    HUANG Chao-Guang; ZHANG Yuan-Zhong

    2002-01-01

    The pulse with a rectangular envelop propagating through the caesium vapour with two gain lines used inthe Wang, Kuzmich, and Dogariu [Nature (London) 406 (2000) 277] experiment is studied. It is shown that there existsan obvious distortion for the pulse.

  18. [A woman in her forties with cancer, syncope and spasms].

    Science.gov (United States)

    Warsame, Mahad Omar; Gamboa, Danil; Nielsen, Erik Waage

    2014-10-14

    A female in her forties with advanced incurable rectal cancer presented to our emergency department after loss of consciousness followed by brief myoclonic jerks in her legs. A cerebral MRI was normal. Her electrocardiogram showed a prolonged QTc interval of 596 milliseconds and hypokalemia was present. She had no family history of congenital long QT syndrome or of cardiovascular disease. She was not on any medication apart from having ingested 100 g caesium carbonate over the previous 11 days as an alternative cancer treatment. Caesium chloride is postulated to increase pH and thereby induce apoptosis in cancer cells. In treatment doses caesium competes with potassium for membrane transport proteins in the cardiac cell membrane and in the reabsorption tubuli of the kidneys. A result is hypokalemia shortly after depolarization during the cardiomyocytes' repolarisation phase or delayed post-depolarisation. Torsade de pointes ventricular arrhythmias, ventricular tachycardia, pump failure and death can follow. A few case reports of adverse effects from caesium ingestion have been published, as well as reports on how caesium is used in animal models to induce ventricular tachycardia, but the hazards of caesium ingestion and its long half-life are not well known in the medical care profession or among patients. As this patient's QTc interval normalised slowly to 413 milliseconds 60 days after stopping caesium ingestion, we consider caesium intoxication and convulsive syncope from a self-terminating ventricular tachycardia as the most probable aetiology. The main message from this case is that alternative medicine can have life-threatening side effects.

  19. Cesium Atomic Fountain Clocks at NMIJ

    Science.gov (United States)

    2010-11-01

    shift in caesium fountain clocks,” Physical Review Letters, 98, 153002. [10] A. Takamizawa, Y. Shirakawa, S. Yanagimachi et al., 2010, “Proposal of a...beam of laser-cooled cesium atoms,” Physical Review, A 60, R4241-R4244. [13] V. Gerginov, N. Nemitz, S. Weyers, et al., 2010, “Uncertainty evaluation of the caesium fountain clock PTB-CSF2,” Metrologia, 47, 65-79.

  20. Spectral range calculation inside the Research Irradiating Facility Army Technology Center using code MCNPX and comparison with the spectra of energy Caesium 137 raised in laboratory; Calculo gama espectral no interior do irradiador de pesquisa do Centro Tecnologico do Exercito utilizando o codigo MCNPX e comparacao com espectros de energia do Cesio 137 levantados em laboratorio

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Renato G.; Rebello, Wilson F.; Cavaliere, Marcos Paulo; Vellozo, Sergio O.; Moreira Junior, Luis, E-mail: renatoguedes@ime.eb.br, E-mail: rebello@ime.eb.br, E-mail: eng.cavaliere@gmail.com, E-mail: vellozo@cbpf.br, E-mail: luisjrmoreira@hotmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Vital, Helio C., E-mail: vital@ctex.eb.br [Centro Tecnologico do Exercito (CTEX), Barra de Guaratiba, RJ (Brazil); Silva, Ademir X., E-mail: ademir@con.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Using the MCNPX code, the objective was to calculate by means of computer simulation spectroscopy range inside the irradiation chamber upper radiator gamma research irradiating facility Army Technology Center (CTEx). The calculations were performed in the spectral range usual 2 points for research purposes irradiating the energy spectra of gamma rays from the source of Cesium chloride 137. Sought the discretization of the spectrum in 100 channels at points of upper bound of 1cm higher and lower dose rates previously known. It was also conducted in the laboratory lifting the spectrum of Cesium-137 source using NaI scintillator detector and multichannel analyzer. With the source spectrum Cesium-137 contained in the literature and raised in the laboratory, both used as reference for comparison and analysis in terms of probability of emission maximum of 0.661 MeV The spectra were quite consistent in terms of the behavior of the energy distributions with scores. The position of maximum dose rate showed absorption detection almost maximum energy of 0.661 MeV photopeak In the spectrum of the position of minimum dosage rate, it was found that due to the removal of the source point of interest, some loss detection were caused by Compton scattering. (author)

  1. Literature study of the radiobiological parameters of Caesium-137 required for evaluating internal irradiation doses as a function of age; Etude bibliographique des parametres radiobiologiques du cesium-137 necessaires a l'evaluation des doses d'irradiation interne en fonction de l'age

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, A. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    This document reassembles information published in scientific literature on radiobiological parameters of Cs-137, necessary for the estimate of the internal irradiation dose of man according to his age (during growth). The data are completed by a commented review of the mathematical models, proposed in order to value the irradiation doses from ingested cesium and the biological parameters. (author) [French] Ce document rassemble les informations publiees dans la litterature scientifique, concernant les parametres radiobiologiqueo du cesium-137, necessaires a l'evaluation des doses d'irradiation interne de l'homme en fonction de l'age. Ces donnees sont completees par une revue commentee des modeles mathematiques proposes en vue de l'evaluation des doses d'irradiation a partir des quantites de cesium ingerees et des parametres biologiques. (auteur)

  2. Interaction of microorganism with caesium and its potential application in bioremediation of radionuclide contamination%微生物与铯的相互作用及其在放射性核素污染环境修复中的应用潜力

    Institute of Scientific and Technical Information of China (English)

    王建龙

    2003-01-01

    含放射性核素的废物在排放前必须进行有效的处理.铯是核电站排放的放射性物质之一.现有的除铯技术,如沸石吸附、离子交换等方法成本较高.利用微生物技术去除铯是目前可以考虑的替代方案,铯具有的独特化学性质决定了铯与微生物之间的相互作用机理不同于其它金属/放射性核素.据报道,自然界中存在大量的微生物可以吸收铯,但不同种类的微生物,其吸收量差别很大,微生物对铯的吸收量受一些环境因素的影响,如操作系统(分批式或连续流)、菌体的固定化、pH值,特别是其它单价阳离子(如K+、Na+)存在与否等.微生物对铯吸收量的差别可能与其单价阳离子转移系统对铯的亲合力有关,通过现代生物技术手段可以分离筛选出对铯具有高度亲合力的微生物.此外,控制微生物的生理状态也可以改变其对铯的亲合力.微生物方法去除铯在放射性核素污染环境的生物修复中具有实用潜力.

  3. 安徽明光凹凸棒石黏土对锶、铯、钴的吸附特性研究%Study on Adsorption Performance of Attapulgite Clay from Mingguang City of Anhui Province for Strontium, Caesium and Cobalt

    Institute of Scientific and Technical Information of China (English)

    王哲; 易发成; 刘艳

    2015-01-01

    采用静态吸附实验方法,研究了吸附时间、溶液pH、吸附剂投加量和溶液初始浓度等因素对凹凸棒石黏土吸附Sr2+、Cs+和Co2的性能,并通过等温吸附模型拟合对其吸附过程及吸附机理进行了探讨.结果表明:凹凸棒石黏土对Sr2+、Cs+和Co2的吸附效果依次为Co2> Cs+>Sr2;Freundlich和D-R等温吸附模型能较好地描述凹凸棒石黏土对Sr2+、Cs+和Co2+的吸附过程,其中,凹凸棒石黏土对Sr2和Cs+的吸附以物理吸附为主,而凹凸棒石对Co2+的吸附过程以化学吸附为主,并且其吸附方式主要为离子交换的方式发生.

  4. 萃取分离-石墨炉原子吸收光谱法测定盐卤中痕量铯的研究%Study on the Determination of Trace Caesium in Bittern by Extraction Separation Graphite Furnace Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    张波; 向立人

    1999-01-01

    采用墨炉原子吸收光谱法(GFAAS)研究盐卤中铯原子化行为和机理,建立了热解石墨管、KNO3-NH4NO3基体改进剂、18-冠-6、溴百里香酚蓝、氯仿萃取分离-GFAAS测定盐卤中铯的方法.用于测定盐卤中痕量铯,特征质量1.4×10-10 g/0.004 4 A;加标回收率89%~105%;相对标准偏差4.13%.

  5. Agricultural Nonpoint Source Pollution Loads Prediction Using Caesium-137 Tracing Technique in Black Soil Region,Northeast China%~(137)Cs示踪技术在黑土区农业非点源污染负荷研究中的应用

    Institute of Scientific and Technical Information of China (English)

    杨育红; 阎百兴; 沈波; 曹会聪

    2010-01-01

    利用~(137)Cs核素示踪和定位监测相结合,研究松嫩平原黑土区3个旱作坡面土壤的流失厚度和流失速率,坡面土壤流失厚度1.20~5.25 mm/a,侵蚀强度1 355.0~7 558.2t/(km~2·a);近40 a来,松嫩平原黑土区年均入河(湖)农业非点源污染负荷分别为TN 1.43t/(km~2·a)、NH_3~-N 15.01 kg/(km~2·a)、NO_3~-N 8.51 kg/(km~2·a)TP0.42 t/(km~2·a)、PO_4~(3-)-P 1.85 kg/(km~2·a);土壤流失氮以有机氮为主;水溶态无机氮占总氮的0.51%,水溶性磷酸盐磷占总磷的0.12%.黑土区农业非点源污染物的输出和水土流失密切相关,深入研究其输移机理及防治措施具有重要的环境意义.

  6. 青海共和盆地土壤风蚀的137Cs法研究(Ⅱ)--137Cs背景值与风蚀速率测定%Application of Caesium-137 Technique on Wind Erosion in Gonghe Basin, Qinghai Province (Ⅱ)-137Cs Reference Inventory and 137Cs Model for Wind Erosion Estimation

    Institute of Scientific and Technical Information of China (English)

    严平; 董光荣; 张信宝; 邹学勇

    2003-01-01

    通过对高寒草原背景值样点(RS7)的分析,将共和盆地的137Cs背景值含量确定为(2 691.78±196.08) Bq*m-2,基本接近北半球137Cs背景值的平均水平,其137Cs剖面满足尖峰分布函数,与公认的理论分布(即负指数分布)相比,呈现出峰值下移和曲线趋平的现象,可能与近几十年来137Cs的稳定下渗有关.应用137Cs背景值剖面分布函数,建立了风蚀速率的137Cs估算模型,估算出四个样方的土壤风蚀速率,并由此转化为区域风蚀速率,计算出共和盆地区域土壤风蚀速率为12.556 t*hm-2*a-1,通过蚀积平衡检验,其误差水平小于10%.并分析了风蚀物的输出途径及其所占比例.

  7. 青海共和盆地土壤风蚀的137Cs法研究(Ⅰ)--137Cs分布特征%Application of Caesium-137 Technique on Wind Erosion in Gonghe Basin, Qinghai Province (Ⅰ)-137Cs Distribution Characteristics

    Institute of Scientific and Technical Information of China (English)

    严平; 董光荣; 张信宝; 邹学勇

    2003-01-01

    土壤风蚀作为土地沙漠化的首要环节,对其准确测定和评估是十分迫切和必要的.放射性核素137Cs作为人类核试验的产物,以其独特的理化性质而成为研究土壤侵蚀和泥沙沉积一种良好的示踪源.137Cs法在水蚀研究领域已取得了显著的进展,而在风蚀研究中的应用却相对不足,目前尚处于探索阶段.作者选择青海共和盆地作为研究区,探讨137Cs法在土壤风蚀研究中应用的可行性.通过对共和盆地不同类型土壤剖面的137Cs取样分析,基本查清了区域137Cs分布的若干特性,测定出不同类型土地137Cs活度的排序为:林地>干湖盆>高寒草原>旱作农田≈干草原>固定沙丘>荒漠草原>流动沙丘>风蚀地,137Cs总量的排序为:干湖盆>林地>流动沙丘>高寒草原>旱作农田≈干草原>固定沙丘>荒漠草原>风蚀地.并分析了一些典型剖面的137Cs深度分布及其机制,将137Cs深度剖面划分为正常剖面、沉积剖面、侵蚀剖面和人为扰动剖面4种型式.沙丘砂由于遭受反复吹失和沉积,其137Cs含量逐渐减小,趋于微量的均匀化;而高寒草原的137Cs含量在区域上也较为均匀,在深度分布上,接近负指数分布曲线保存了相对完好的137Cs初始沉积剖面,是理想的137Cs背景值样点.

  8. {sup 137}Cs in French soils: Deposition patterns and 15-year evolution

    Energy Technology Data Exchange (ETDEWEB)

    Roussel-Debel, Sylvie [Institute for Radioprotection and Nuclear Safety (France)]. E-mail: sylvie.roussel-debet@irsn.fr; Renaud, Philippe [Institute for Radioprotection and Nuclear Safety (France); Metivier, Jean-Michel [Institute for Radioprotection and Nuclear Safety (France)

    2007-03-15

    Around 2000 surface samples have been taken from French soil at around twenty stations over the last fifteen years. Caesium 137, the only artificial radionuclide in the terrestrial environment currently detectable with gamma spectroscopy, was measured in the samples. The levels of caesium activity were compared to deposition estimates for deposits from atmospheric weapons tests and Chernobyl fallout. Since the start of data acquisition, specific activity in the samples has decreased with a mean effective half-life of between 8 and 11 y, for meadow soil and agricultural soil respectively. These field observations confirm that the conventional soil migration-retention model, which uses distribution coefficient Kd, is insufficient for modelling caesium distribution in the surface soil layer. Although the differences between sites tend to diminish with time, surface specific activity in agricultural and meadow soil varies on average from a few Bq to several tens of Bq per kg of dry matter.

  9. {sup 137}Cs in French soils. Deposition patterns and 15-year evolution

    Energy Technology Data Exchange (ETDEWEB)

    Roussel-Debel, Sylvie; Renaud, Philippe; Metivier, Jean-Michel [Institute for Radioprotection and Nuclear Safety, Clamart (France)

    2007-03-15

    Around 2000 surface samples have been taken from French soil at around twenty stations over the last fifteen years. Caesium 137, the only artificial radionuclide in the terrestrial environment currently detectable with gamma spectroscopy, was measured in the samples. The levels of caesium activity were compared to deposition estimates for deposits from atmospheric weapons tests and Chernobyl fallout. Since the start of data acquisition, specific activity in the samples has decreased with a mean effective half-life of between 8 and 11 y, for meadow soil and agricultural soil respectively. These field observations confirm that the conventional soil migration-retention model, which uses distribution coefficient Kd, is insufficient for modelling caesium distribution in the surface soil layer. Although the differences between sites tend to diminish with time, surface specific activity in agricultural and meadow soil varies on average from a few Bq to several tens of Bq per kg of dry matter. (author)

  10. Measurement of the adsorption of radiocaesium on clays: factors affecting the extrapolation to in situ conditions

    Energy Technology Data Exchange (ETDEWEB)

    Staunton, S.; Roubaud, M. [INRA-ENSAM, 34 - Montpellier (France)

    1994-12-31

    The aim of the study is to identify the factors most likely to cause discrepancies between measured and true Kd values (distribution coefficient) used for the measure of adsorption of radiocaesium on solid particles. Values of a trace amount of caesium 137 have been measured in dilute suspensions containing clay minerals (clay may be used as barrier for radioactive wastes disposal). Parameters such as clay mineralogy, charge compensating cation, ionic strength and pH of the solution, concentration of caesium and presence of a soil extracted fulvic acid, were varied and their effects analyzed. Only the pH has no effect on Kd. The Kd is always a function of the caesium concentration. 3 figs., 49 refs.

  11. A semiconductor laser system for the production of antihydrogen

    CERN Document Server

    Mullers, A; Kolbe, D; Diehl, T; Koglbauer, A; Sattler, M; Stappel, M; Steinborn, R; Walz, J; Gabrielse, G; Kalra, R; Kolthammer, W S; McConnell, R P; Richerme, P; Fitzakerley, D W; George, M C; Hessels, E A; Storry, C H; Weel, M; Grzonka, D; Oelert, W

    2012-01-01

    Laser-controlled charge exchange is a promising method for producing cold antihydrogen. Caesium atoms in Rydberg states collide with positrons and create positronium. These positronium atoms then interact with antiprotons, forming antihydrogen. Laser excitation of the caesium atoms is essential to increase the cross section of the charge-exchange collisions. This method was demonstrated in 2004 by the ATRAP collaboration by using an available copper vapour laser. For a second generation of charge-exchange experiments we have designed a new semiconductor laser system that features several improvements compared to the copper vapour laser. We describe this new laser system and show the results from the excitation of caesium atoms to Rydberg states within the strong magnetic fields in the ATRAP apparatus.

  12. ACCUMULATION OF CS-134 IN THE OAT DEPENDING ON SOIL CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    TZ BINEVA

    2005-07-01

    Full Text Available Vegetation pot experiments with spring oats, cultivar Obrazcov Chifl ik – 4, were carried out. The plants were grown on four different soil types, typical for Bulgaria: Haplustoll, Udolls, Ustifl uvents, Albaqualf /USA. The soils were contaminated with the Cs-134. It was concluded that the radio-caesium accumulates unevenly in the different plant organs, as its highest concentration was found in the leaves and lowest in the grains of the researched culture. Substantial differences were discovered in the accumulation of caesium –134 in the plants, depending on the soil differences. According to the accumulation of the radio-caesium in the plants, the different soils can be arranged as follows: Albaqualf > Vdolls >Ustifl uvents > Haplustoll.

  13. Activation processes on GaAs photocathode by different currents of oxygen source

    Science.gov (United States)

    Miao, Zhuang; Shi, Feng; Cheng, Hongchang; Wang, Shufei; Zhang, Xiaohui; Yuan, Yuan; Chen, Chang

    2015-04-01

    In order to know the influence of activation processes on GaAs photocathodes, three GaAs samples were activated by a fixed current of cesium source and different currents of oxygen source. The current of caesium source is same during activation to ensure initial adsorption of caesium quantum is similar, which is the base to show the difference during alternation activation of caesium and oxygen. Analysed with the activation data, it is indicated that Cs-to-O current ratio of 1.07 is the optimum ratio to obtain higher sensitivity and better stability. According to double dipole model, stable and uniform double dipole layers of GaAs-O-Cs:Cs-O-Cs are formed and negative electron affinity is achieved on GaAs surface by activation with cesium and oxygen. The analytical result is just coincident with the model. Thus there is an efficient technological method to improve sensitivity and stability of GaAs photocathode.

  14. Synthesis of derivatives of tetronic acid and pulvinic acid. Total synthesis of norbadione A; Synthese de derives de l'acide tetronique et de l'acide pulvinique. Synthese totale de la norbadione A

    Energy Technology Data Exchange (ETDEWEB)

    Mallinger, A

    2008-11-15

    When vegetables like mushrooms are contaminated by radioactive caesium 137, this radioactive caesium is associated to norbadione A, a natural pigment present in two mushroom species and which can be used as a caesium decorporation agent or maybe as protection agent against ionizing radiations. Within this perspective, this research report describes the biosynthesis and the structure and properties of the norbadione A and of pulvinic acids (physicochemical properties, anti-oxidizing properties). Then, it presents the various tetronic acids (3-acyl-, 3-alkyl-, 3-alkoxy-, 3-aryl-tetronic acids and non 3-substituted tetronic acids), their synthesis path as they are described in the literature, and presents a new synthesis approach using a tandem reaction (with different esters or hydroxy esters) and the synthesis of tetronic acids. The author also proposes a new synthesis way for methyl pulvinates, and finally reports the work on the development of a total synthesis of the norbadione A.

  15. Chemical reactions of fission product deposits and iodine transport in primary circuit conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kalilainen, Jarmo, E-mail: jarmo.kalilainen@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1000, BI7, FI02044 VTT Espoo (Finland); Kärkelä, Teemu; Zilliacus, Riitta; Tapper, Unto; Auvinen, Ari [VTT Technical Research Centre of Finland, P.O. Box 1000, BI7, FI02044 VTT Espoo (Finland); Jokiniemi, Jorma [VTT Technical Research Centre of Finland, P.O. Box 1000, BI7, FI02044 VTT Espoo (Finland); University of Eastern Finland, Department of Environmental Science, P.O. Box 1627, FI-70211 Kuopio (Finland)

    2014-02-15

    Highlights: • With CsI precursor, 20% of released iodine was in gaseous form in steam flow at 650 °C. • In similar conditions with Mo, gaseous iodine fraction was increased to 38–79%. • Boron trapped most of the caesium and iodine was almost completely released as gas. - Abstract: The objective of this work was to examine the chemical reactions taking place on primary circuit surfaces and their effect on fission product transport in a severe nuclear reactor accident. Especially transport of gaseous and aerosol phase iodine was studied. Caesium iodide (CsI) was used as precursor material for iodine species. Also, effects of molybdenum and boron on transport of iodine were investigated. The experimental work showed that when CsI alone was used as a precursor, as much as 20% of the released iodine was in gaseous form and the rest as aerosol particles. Aerosol particles were most likely CsI. When the amount of hydrogen in the carrier gas was increased, the fraction of gaseous iodine decreased. When Boron was added to the precursor, a glassy caesium borate surface was formed on the crucible. Boron trapped most of the caesium and also a fraction of iodine, causing almost all released iodine to be in gaseous form. When Mo was introduced in the precursor, most of the iodine was again released in gaseous form. Oxidised Mo reacted with caesium releasing iodine from CsI. The effect of Mo on iodine transport depended much on H{sub 2} concentration and was observed to be substantially greater on stainless steel surface. When stainless steel crucible was used, Mo was found in small amounts from aerosol particles, indicating that it was probably released as caesium molybdate or as molybdenum oxide.

  16. Dicaesium diaquabis(methylenediphosphonato-κ2O,O′cobaltate(II

    Directory of Open Access Journals (Sweden)

    Johan A. Venter

    2011-10-01

    Full Text Available The asymmetric unit of the title compound, Cs2[Co(CH4O6P22(H2O2], is comprised of one bidentate methylenediphosphonate ligand and one water molecule which are coordinated to the CoII atom, as well as a caesium counter-cation. The Co atom occupies a special position on a crystallographic inversion center. The caesium ion is octahedrally coordinated by six O atoms with Cs—O distances ranging from 3.119 (2 to 3.296 (2 Å. A three-dimensional network is formed through O—H...O hydrogen bonds.

  17. Removal of radionuclides at a waterworks

    DEFF Research Database (Denmark)

    Gäfvert, T.; Ellmark, C.; Holm, E.

    2002-01-01

    filtration and from the municipal distribution network. The samples were analysed with respect to their content of uranium, thorium, polonium, radium, plutonium and caesium. The results show a high removal capacity for uranium (about 85%), thorium (>90%), plutonium (>95%) and polonium (>90......% in the coagulation–flocculation process) while caesium, strontium and radium pass through the purification process with almost unchanged activity concentrations. During transportation of the water in the tunnel it was also observed that infiltration of groundwater leads to a change in isotopic ratios and/or activity...

  18. Bichromatic state-insensitive trapping of cold 133Cs-87Rb atomic mixtures

    Science.gov (United States)

    Metbulut, M. M.; Renzoni, F.

    2015-12-01

    We investigate simultaneous state-insensitive trapping of a mixture of two different atomic species, Caesium and Rubidium. The magic wavelengths of the Caesium and Rubidium atoms are different, 935.6 and 789.9 nm respectively, thus single-frequency simultaneous state-insensitive trapping is not possible. We thus identify bichromatic trapping as a viable approach to tune the two magic wavelengths to a common value. Correspondingly, we present several common magic wavelength combinations appropriate for simultaneous state-insensitive trapping of the two atomic species.

  19. An analytical approach to γ-ray self-shielding effects for radioactive bodies encountered nuclear decommissioning scenarios.

    Science.gov (United States)

    Gamage, K A A; Joyce, M J

    2011-10-01

    A novel analytical approach is described that accounts for self-shielding of γ radiation in decommissioning scenarios. The approach is developed with plutonium-239, cobalt-60 and caesium-137 as examples; stainless steel and concrete have been chosen as the media for cobalt-60 and caesium-137, respectively. The analytical methods have been compared MCNPX 2.6.0 simulations. A simple, linear correction factor relates the analytical results and the simulated estimates. This has the potential to greatly simplify the estimation of self-shielding effects in decommissioning activities.

  20. Extended superstructure in Tl-rich liquid Cs-Tl alloys

    NARCIS (Netherlands)

    van der Aart, SA; Verkerk, P; Badyal, YS; van der Lugt, W

    1998-01-01

    The structure factors of liquid caesium-thallium alloys with thallium concentrations of 50 to 85 at. % have been measured by means of neutron diffraction. They exhibit a prepeak which shifts to smaller wave vectors with increasing thallium content. This result is explained using a model in which neu

  1. Biological effects of ionizing radiations. Radiological accident from Goiania, GO, Brazil; Efeitos biologicos das radiacoes ionizantes. Acidente radiologico de Goiania

    Energy Technology Data Exchange (ETDEWEB)

    Okuno, Emico, E-mail: emico.okuno@if.usp.br [Instituto de Fisica da Universidade de Sao Paulo (IF-USP), SP (Brazil)

    2013-01-15

    This article presents the fundaments of radiation physics, the natural and artificial sources, biological effects, radiation protection. We also examine the sequence of events that resulted in Goiania accident with a source of caesium-137 from abandoned radiotherapy equipment and its terrible consequences. (author)

  2. The Optically Pumped Cs Frequency Standard at the NRLM

    Science.gov (United States)

    1987-12-01

    References 1. J.L. Picqu6, "Hyperfine optical pumping of a cesium atomic beam, and applications," Metrologia, vo1.13, pp.115-119, 1977. 2. M. Arditi and... Arditi , "A caesium beam atomic clock with laser optical pumping, as a potential frequency standard," Metrologia, vo1.18, pp.59-66, 1982. 4. G

  3. Radioactivity in Norwegian Waters: Distribution in seawater and sediments, and uptake in marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Heldal, Hilde Elise

    2001-07-01

    Prior to the detonation of the first thermonuclear bomb, small amounts of radioactivity, for example in mineral water, were considered to be health enriching. Negative experiences related to thermonuclear bombs and several nuclear accidents have, however, changed people's attitude towards radioactivity during the past 40-50 years. Today, there is a common concern for regular and potential accidental releases of radioactivity from sources such as Sellafield. Although this is important, incorrect assessments of the effects of these releases (e.g. created by uncritical journalism) have the potential to harm the country's fisheries and economy. Therefore, it is of major importance to document up-to-date levels of radioactive contamination of the marine environment, and be able to place these into the proper perspectives. The main topics of the thesis may be summarised as follows: (1) Distribution of Caesium-137, Plutonium-238, Plutonium-239,240 and Americium-241 in sediments with emphasis on the Spitsbergen-Bear Island area, (2) Uptake of Caesium-137 in phytoplankton representative for the Barents and Norwegian Seas phytoplankton communities (laboratory experiments), (3) Bioaccumulation of Caesium-137 in food webs in the Barents and Norwegian Seas, (4) Geographical variations of Caesium-137 in harbour porpoises (Phocoena phocoena) along the Norwegian coast, (5) Transport times for Technetium-99 from Sellafield to various locations along the Norwegian coast and the Arctic Ocean.

  4. The radiological accident of Goiania and its legislative implications; O acidente radiologico de Goiania e suas implicacoes legistativas

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Ieda Rubens

    2001-07-01

    Starting from a reflective view of the historical relationships existing between mankind and nature, this work seeks to pinpoint the today crises and ecological awareness in order to better understand the sparse use of various forms of assault relating to the environment, emphasising the caesium 137 accident as an object of this research. The destructive crisis of capitalism and its ethics, has the ecological crisis as only one of its aspects, however, the caesium 137 accident in Goiania was never left to be treated without pertaining to that crisis. In this way, tackling the issue of the caesium 137 and its unfolding disclosures became impossible not to mention the dimensions of cultural, philosophy, politics, economics and legal issues of the accident. Therefore, within the scope of this research, the Caesium 137 accident was treated as to avoid a fragmented analysis. It was also been transformed into a interdisciplinary work, as it shows the configuration of many concepts, but not legal matters in itself, because the Law itself, as a science, does not have an object through excellency. (author)

  5. A probabilistic dispersion model applied to the long-range transport of radionuclides from the Chernobyl accident

    DEFF Research Database (Denmark)

    Lauritzen, B.; Mikkelsen, T.

    1999-01-01

    . A corresponding effective deposition length for caesium, R-Cs, defined las the effective distance from Chernobyl to where the aerosols have been deposited, is found to be R-Cs approximate to 1000 km. From the observations of the regional variability of the Chernobyl fallout a simple probabilistic assessment...

  6. Dynamic behaviour of Cs-137 contamination in trees of the Briansk region, Russia

    DEFF Research Database (Denmark)

    Fogh, C.L.; Andersson, Kasper Grann

    2001-01-01

    to the growth years at approximately 1986. Neutron activation analysis was used to analyse for stable Cs. The results showed that the relationship between concentrations of Cs-137 and stable caesium is much higher in the newer parts of growing trees than in the older parts. Together with a tendency of inward...

  7. Creation of an Ultracold Plasma by Photoionizing Laser-Cooled Cesium Atom

    Institute of Scientific and Technical Information of China (English)

    JING Qun; FENG Zhi-Gang; ZHANG Lin-Jie; LI Chang-Yong; ZHAO Jian-Ming; JIA Suo-Tang

    2008-01-01

    @@ The signals of ultracold plasma are observed by two-photon ionization of laser-cooled atom in a caesium magneto-optical trap.A simple model has been introduced to explain the creation of plasma, and the mechanism is further investigated by changing the energy of a pulsed dye laser and the number of initial cooled atoms.

  8. Alkali metal and ammonium chlorides in water and heavy water (binary systems)

    CERN Document Server

    Cohen-Adad, R

    1991-01-01

    This volume surveys the data available in the literature for solid-fluid solubility equilibria plus selected solid-liquid-vapour equilibria, for binary systems containing alkali and ammonium chlorides in water or heavy water. Solubilities covered are lithium chloride, sodium chloride, potassium chloride, rubidium chloride, caesium chloride and ammonium chloride in water and heavy water.

  9. Process for the conversion of sugars to lactic acid and 2-hydroxy-3-butenoic acid or esters thereof comprising a metallo-silicate material and a metal ion

    DEFF Research Database (Denmark)

    2015-01-01

    A process for the preparation of lactic acid and 2-hydroxy- 3-butenoic acid or esters thereof from a sugar in the presence of a metallo-silicate material, a metal ion and a solvent, wherein the metal ion is selected from one or more of the group consisting of potassium ions, sodium ions, lithium ...... ions, rubidium ions and caesium ions....

  10. CsMgPO4

    Directory of Open Access Journals (Sweden)

    Nikolay S. Slobodyanik

    2009-08-01

    Full Text Available Caesium magnesium orthophosphate is built up from MgO4 and PO4 tetrahedra (both with . m. symmetry linked together by corners, forming a three-dimensional framework. The Cs atoms have .m. site symmetry and are located in hexagonal channels running along the a- and b-axis directions.

  11. Observation of single neutral atoms in a large-magnetic-gradient vapour-cell magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; He Jun; Qiu Ying; Yang Bao-Dong; Zhao Jiang-Yan; Zhang Tian-Cai; Wang Jun-Min

    2008-01-01

    Single caesium atoms in a large-magnetic-gradient vapour-cell magneto-optical trap have been identified. The trapping of individual atoms is marked by the steps in fluorescence signal corresponding to the capture or loss of single atoms. The typical magnetic gradient is about 29 mT/cm, which evidently reduces the capture rate of magneto-optical trap.

  12. Molecular structures of viruses from Raman optical activity

    DEFF Research Database (Denmark)

    Blanch, Ewan W.; Hecht, Lutz; Syme, Christopher D.

    2002-01-01

    (top component) of cowpea mosaic virus from those of the intact middle and bottom-upper components separated by means of a caesium chloride density gradient, the ROA spectrum of the viral RNA was obtained, which revealed that the RNA takes up an A-type single-stranded helical conformation...

  13. Realisation of a Frequency Standard Using an Atomic Fountain

    CERN Document Server

    Michaud, A; Zetie, K P; Cooper, C J; Hillenbrand, G; Lorent, V; Steane, A; Foot, C J

    2005-01-01

    We report the realisation and preliminary study of a frequency standard using a fountain of laser cooled caesium atoms. Our apparatus uses a magneto-optical trap as a source of cold atoms and optical pumping to prepare the atoms in the correct state before they enter the microwave cavity.

  14. Speciation analysis of 129I, 137Cs, 232Th, 238U, 239Pu and 240Pu in environmental soil and sediment

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hansen, Violeta; Hou, Xiaolin

    2012-01-01

    is predominated in nitric acid leachable fraction and caesium is primarily observed in nitric acid and aqua regia leachable fractions and residue. Our analytical results reveal that around 50% of uranium might still remain in the residue which could not be extracted with aggressive acid, namely, aqua regia....

  15. Consequences of severe radioactive releases to Nordic Marine environment

    DEFF Research Database (Denmark)

    Iosjpe, M.; Isaksson, M.; Joensen, H.P.

    - or minor – radioactive releases to Nordic marine environment. As a reference, the release amounts from a 3000 MWth reactor size were used. Based on source term analyses, the chosen release fractions in the study were: iodine 20% (of the total core inventory), caesium 10%, tellurium 10%, strontium 0...

  16. Electrophysiological properties of hypoglossal motoneurons of guinea-pigs studied in vitro

    DEFF Research Database (Denmark)

    Mosfeldt Laursen, A; Rekling, J C

    1989-01-01

    responses showed initial sags and rebound responses in all healthy cells and these were eliminated by caesium. Barium, substituted for calcium, unleashed a depolarizing plateau potential sensitive to tetrodotoxin, indicating the presence of a persistent sodium conductance.(ABSTRACT TRUNCATED AT 400 WORDS)...

  17. The Impact of Agricultural Soil Erosion on the Global Carbon Cycle

    Science.gov (United States)

    Agricultural soil erosion is thought to perturb the global carbon cycle, but estimates of its effect range from a source of 1 Pg/year to a sink of the same magnitude. By using Caesium-137 and carbon inventory measurements from a large-scale survey, we found consistent evidence for an erosion-induced...

  18. Performance and Applications of an Ensemble of Atomic Fountains

    Science.gov (United States)

    2012-01-01

    clock based time scale,” Metrologia 49, pp. 180-188 (2012). [2] T. Parker, S. Jefferts, T. Heavner, and E. Donley, “Operation of the NIST-F1 caesium...fountain primary standard with a maser ensemble, including the impact of frequency transfer noise,” Metrologia 42, pp. 423-430 (2005). [3] J. Guéna, et

  19. A functional mimic of natural peroxidases : synthesis and catalytic activity of a non-heme iron/peptide hydroperoxide complex

    NARCIS (Netherlands)

    Choma, Christin T.; Schudde, Ebe P.; Kellogg, Richard M.; Robillard, George T.; Feringa, Ben L.

    1998-01-01

    Site-selective attachment of unprotected peptides to a non-heme iron complex is achieved by displacing two halides on the catalyst by peptide caesium thiolates. This coupling approach should be compatible with any peptide sequence provided there is only a single reduced cysteine. The oxidation activ

  20. The Roll of Canopy on Interception and Redistribution of Anthropogenic Radionuclides Derived from Fukushima Daiichi Nuclear Power Plant Accident in Coniferous Forest Plantations

    Science.gov (United States)

    Kato, H.; Onda, Y.; Kawaguchi, S.; Gomi, T.

    2011-12-01

    Soil, vegetation and other ecological compartments are expected to be highly contaminated by the deposited radionuclides after the Fukushima Daiichi nuclear power plant (NPP) accident triggered by a magnitude 9.1 earthquake and the resulting tsunami on Marchi 11, 2011. A large proportion of radionuclides which deposited on forest area are trapped by canopies, throughfall and stemflow are the most important pathways for the input of radionuclides into the soil of forest floor. In this study, to investigate the roll of forest canopy on interception and redistribution of the deposited radionuclides, a series of field monitoring experiment of throughfall and stemflow were conducted in coniferous forest plantations in Tochigi prefecture, 170 km southwest from the NPP. A set of 20 throughfall collectors with latticelike distribution and 5 stemflow collectors were located in the 10m × 10m interception plot, and the activities of caesium (137Cs, 134Cs) and radioiodine (131I) in throughfall and stemflow were quantified by using a high purity n-type germanium coaxial gamma ray detectors. Rainfall, throughfall, and stemflow samples were collected from 10 rainfall events, which includes first rainfall event after the NPP accident. The cumulative fallout of radionuclides in the study site was 3400 Bq m-2 for 137Cs, 3300 Bq m-2 for 134Cs, and 26000 Bq m-2 for 131I, respectively. The 137Cs in rainfall decreased exponentially with time since the NPP accident. For the rainfall event of 28 March, which is first rainfall event after the NPP accident, both the amount and concentration of caesium clearly increased with throughfall, whereas the concentration of radioiodine decreased with throughfall. For the subsequent rainfall events, the concentration of caesium decreased with throughfall, whereas radioiodine was not detected as a result of decay due to short half-life. At the end of May, approximately 30% and 60% of total caesium deposited after the NPP accident remained on the

  1. Cesium-137 global fallout into the Ob river basin and its influence on the Kara sea contamination - Weapons fallout cesium-137 in the Ob' catchment landscapes and its influence on radioactive contamination of the Kara sea: Western Siberia, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Semenkov, Ivan N.; Miroshnikov, Alexey Yu. [The Organization of Russian Academy of Sciences Institute of geology of ore deposits, petrography, mineralogy and geochemistry Russian Academy of Sciences (Russian Federation)

    2014-07-01

    There are several high level {sup 137}Cs anomaly zones detected in the deposits of the SW part of the Kara Sea. These anomaly zones were formed in the Ob' and the Enisey river estuaries due to the geochemical 'river-sea' boarder barrier. Level of radiocaesium specific activity reaches 120 Bq*kg{sup -1} in the deposits from these zones. Radiochemical enterprises occur in the both river basins. Their activity results in caesium-137 transfer into the river net. Vast area is contaminated by {sup 137}Cs after nuclear weapons in Semipalatinsk test-site and Kyshtym disaster in the Ob' river basin. Moreover, caesium comes to the Ob' and the Enisey river basins with global atmospheric fallout. The inflow of global fallout caesium-137 to the catchments is 660 kCi (320 kCi including radioactive decay) that is 4 times higher than {sup 137}Cs emission due to Fukushima disaster. Therefore, these river basins as any other huge catchment are an important sources of radioactive contamination of the Arctic Ocean. The aim of our research is to study behavior of global fallout caesium-137 in the landscapes of the Ob and the Enisey river basins. We studied caesium-137 behavior on the example of first order catchments in taiga, wetland, forest-steppe, steppe, and semi-arid landscapes. Geographic information system (GIS) was made. The tenth-order catchments (n=154, Horton coding system) shape 20-groups due to topsoil properties controlling cesium mobility. Eleven first-order basins, characterized 7 groups of tenth order catchments, were studied. And 700 bulk-core soil samples were collected in 2011-2013. Cesium runoff is calculated for 3 first-order river basins in taiga and forest-steppe landscapes. Storage of global fallout caesium-137 declines from undisturbing taiga first-order river basin (90% of cumulative fallout including radioactive decay)> arable steppe and fores-steppe (70 - 75%)> undisturbing wetland (60%). Caesium-137 transfer is high in arable lands

  2. Influence of alkali and alkaline earth elements on the uptake of radionuclides by Pleurototus eryngii fruit bodies

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, J., E-mail: fguillen@unex.es [LARUEX, Dpt. Applied Physics, Faculty of Veterinary Science, University of Extremadura, Avda. Universidad, s/n, 10071 Caceres (Spain); Baeza, A.; Salas, A. [LARUEX, Dpt. Applied Physics, Faculty of Veterinary Science, University of Extremadura, Avda. Universidad, s/n, 10071 Caceres (Spain)

    2012-04-15

    In the literature, there are many data available on radionuclide contents and their transfer to different species of mushrooms. There are some variables, however, which affect the transfer but are very difficult to observe in collected wild mushrooms. An example is the effect of different concentrations of alkali and alkaline earth elements in the soil. Modification of these concentrations in the soil solution has traditionally been used as a countermeasure to deal with radioactively contaminated areas. In the present work, fruiting bodies of Pleurotus eryngii, a saprophytic mushroom, were grown under controlled laboratory conditions, varying the content of alkali (potassium and caesium) and alkaline earth (calcium and strontium) elements. The transfer of {sup 134}Cs, {sup 85}Sr, and {sup 60}Co (added to the cultures) and of natural {sup 210}Pb was analysed by increasing the content of each stable element considered. A significant, but nonlinear, enhancement of stable caesium and {sup 134}Cs was observed with increasing content of stable caesium in the substrate/mycelium. The transfer of {sup 85}Sr decreased with the addition of each stable cation, whereas the {sup 60}Co and {sup 210}Pb transfers were unaffected. - Highlights: Black-Right-Pointing-Pointer The addition of stable potassium did not affect the uptake of radiocaesium. Black-Right-Pointing-Pointer The addition of stable caesium increased the stable caesium and {sup 134}Cs content in the fruiting bodies of Pleurotus eryngii. Black-Right-Pointing-Pointer The addition of calcium reduced the content of calcium and {sup 85}Sr in the fruiting bodies. Black-Right-Pointing-Pointer These countermeasures did not work properly in the case of {sup 60}Co and {sup 210}Pb, no effect was observed.

  3. Formation of cold molecules through the photo-association of cold atoms of Cesium. Existence of long range forces between between cold excited atoms of Cesium; Formation de molecules froides par photoassociation d'atomes froids de cesium. Mise en evidence de forces a longue portee entre atomes froids excites de cesium

    Energy Technology Data Exchange (ETDEWEB)

    Comparat, D

    1999-09-01

    This thesis deals with the experimental study and the theoretical interpretation of the processes involved in photo-association and the formation of cold caesium molecules. It also presents a study of the dipolar forces between a pair of cold excited caesium atoms. We present here the first photo-association experiment on cold caesium atoms: two cold atoms absorb a photon to form an excited electronically excited molecules in a rotation-vibration level. The first production of cold molecules which was realised experimentally, after the spontaneous deexcitation of the photo-associated molecules, is described, stressing the role of the potential well of the molecular states O{sub g}{sup -}(6s+6p{sub 3/2}) or 1{sub u} (6s+6p{sub 3/2}) of caesium. The detection of the formed caesium molecules is based on a two-photons resonant ionisation that creates Cs{sub 2}{sup +} ions, afterwards selectively detected. Temperatures around 20-200 {mu}K have been measured. The photo-associative spectroscopy is described on the theoretical point of view: a detailed theoretical study allows to calculate precisely the asymptotic parts of the potential curves. On the experimental point of view, we present the spectroscopy of the extern potential well of the caesium state O{sub g}{sup -}(6s+6p{sub 3/2}) and the construction of an effective potential curve of the RKR type. A unified theory of photo-association in weak field, considered as a collision assisted by laser, is developed. The cold atoms experiments allow to study and control the collision between two atoms whose mutual interaction is of the dipole-dipole type. Two different physical systems are studied: a sample of Rydberg atoms, and the photo-association process which is a laser-assisted collision. A modification of the motion of one pair of atoms makes it possible to control the bipolar forces and to choose the atoms relative speeds. (author)

  4. Liquid high-level waste storage - can we tolerate it?

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, P. [Terramares Group (United Kingdom)

    1996-12-31

    High-level radioactive waste from reprocessing is stored at British Nuclear Fuel`s Sellafield site in High Active Storage Tanks (HAST`s), which require constant cooling and ventilation. The author argues that, containing as they do, about 100 times the caesium 137 released during the Chernobyl accident, these containment tanks represent an unacceptably high risk of a major release of caesium 137, a volatile gamma-emitter with a half-life of about 30 years. It is readily transferred into food chains and difficult to remove from soils, tarmac and concrete. Still worse, it is argued, are the tens of thousands of cancers and other biological radiation effects likely to occur as a result of such a release. He argues for the vitrification of all such highly active liquid wastes, which would slow further reprocessing down to accommodate the current backlog. (UK).

  5. Searching for an Oscillating Massive Scalar Field as a Dark Matter Candidate Using Atomic Hyperfine Frequency Comparisons.

    Science.gov (United States)

    Hees, A; Guéna, J; Abgrall, M; Bize, S; Wolf, P

    2016-08-05

    We use 6 yrs of accurate hyperfine frequency comparison data of the dual rubidium and caesium cold atom fountain FO2 at LNE-SYRTE to search for a massive scalar dark matter candidate. Such a scalar field can induce harmonic variations of the fine structure constant, of the mass of fermions, and of the quantum chromodynamic mass scale, which will directly impact the rubidium/caesium hyperfine transition frequency ratio. We find no signal consistent with a scalar dark matter candidate but provide improved constraints on the coupling of the putative scalar field to standard matter. Our limits are complementary to previous results that were only sensitive to the fine structure constant and improve them by more than an order of magnitude when only a coupling to electromagnetism is assumed.

  6. Negative hydrogen ion production mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Bacal, M. [UPMC, LPP, Ecole Polytechnique, UMR CNRS 7648, Palaiseau (France); Wada, M. [School of Science and Engineering, Doshisha University, Kyoto 610-0321 (Japan)

    2015-06-15

    Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

  7. Realization of a time-scale with an optical clock

    CERN Document Server

    Grebing, C; Dörscher, S; Häfner, S; Gerginov, V; Weyers, S; Lipphardt, B; Riehle, F; Sterr, U; Lisdat, C

    2015-01-01

    Optical clocks are not only powerful tools for prime fundamental research, but are also deemed for the re-definition of the SI base unit second as they surpass the performance of caesium atomic clocks in both accuracy and stability by more than an order of magnitude. However, an important obstacle in this transition has so far been the limited reliability of the optical clocks that made a continuous realization of a time-scale impractical. In this paper, we demonstrate how this dilemma can be resolved and that a time-scale based on an optical clock can be established that is superior to one based on even the best caesium fountain clocks. The paper also gives further proof of the international consistency of strontium lattice clocks on the $10^{-16}$ accuracy level, which is another prerequisite for a change in the definition of the second.

  8. Status of the atomic fountain clock at the National Research Council of Canada

    Science.gov (United States)

    Beattie, S.; Alcock, J.; Jian, B.; Gertsvolf, M.; Bernard, J.

    2016-06-01

    Despite the rapid advances in optical frequency standards, caesium fountain clocks retain a critical role as the most accurate primary frequency standards available. At the National Research Council Canada, we are working to develop a second generation caesium fountain clock. Work is currently underway to improve several systems of FCs1, such as the laser system and microwave local oscillator, which will be incorporated into its refurbished version, FCs2. In addition, we have added an optical pumping stage which has increased the detected atom number by over a factor of six. In collaboration with the National Physical Laboratory (NPL), we are planning on replacing the physics package of FCs1. We will report on several recent improvements to FCs1, along with our progress in the development of FCs2.

  9. An analytical model of Faraday rotation in hot alkali metal vapours

    CERN Document Server

    Kemp, Stefan L; Cornish, Simon L

    2011-01-01

    We report a thorough investigation into the absorptive and dispersive properties of hot caesium vapour, culminating in the development of a simple analytical model for off-resonant Faraday rotation. The model, applicable to all hot alkali metal vapours, is seen to predict the rotation observed in caesium, at temperatures as high as 115 $^{\\circ}$C, to within 1% accuracy for probe light detuned by greater than 2 GHz from the $D_{2}$ lines. We also demonstrate the existence of a weak probe intensity limit, below which the effect of hyperfine pumping is negligible. Following the identification of this regime we validate a more comprehensive model for the absorption and dispersion in the vicinity of the $D_{2}$ lines, implemented in the form of a computer code. We demonstrate the ability of this model to predict Doppler-broadened spectra to within 0.5% rms deviation for temperatures up to 50 $^{\\circ}$C.

  10. Negative ion studies on the RF plasma device MAGPIE

    Science.gov (United States)

    Willett, Hannah; Santoso, Jesse; Corr, Cormac; Gibson, Kieran

    2016-10-01

    Neutral beam injection (NBI) systems provide both heating and current drive in tokamak fusion reactors. High energy (> 1 MeV) neutral beams are produced by neutralising accelerated ions, for which negative ions are used; the neutralisation cross section for positive ions becomes negligible at these energies. This requires very high throughput negative ion sources. Currently this is achieved using inductively coupled plasma sources, which incorporate caesium to improve the production rate. It has been proposed that helicon plasma sources could provide a more efficient, higher throughput method of producing negative ions for NBI, possibly even removing the need for caesium. We report on studies of the negative hydrogen ion population in the MAGPIE helicon device (Australian National University) under a variety of operating conditions. The probe-based laser photodetachment method and Langmuir probes are employed to estimate the negative hydrogen ion density throughout the device. Initial results support the viability of helicon-based negative ion sources.

  11. Saturation of Photoassociation in Cs Magneto-optical Trap

    Institute of Scientific and Technical Information of China (English)

    MA Jie; WANG Li-Rong; JI Wei-Bang; XIAO Lian-Tuan; JIA Suo-Tang

    2007-01-01

    An ultrahigh resolution photoassociation spectrum of caesium atoms in a magneto-optical trap is presented. Hyperfine structure of the excited state molecule is obtained by using the lock-in method based on modulated cold atoms in this spectrum. Amplitude of resonant lines related to the rotational levels increases with photoassociation laser intensity, and saturation effect of photoassociation of cold atoms is observed in our experiment. The saturation intensity of photoassociation is deduced by fitting the experimental data to a saturation model based on scattering theory. Differences among saturation intensities of different rotational progressions in the v = 55vibrational state of the caesium molecular long-range O-g state have been found.

  12. Searching for an oscillating massive scalar field as a dark matter candidate using atomic hyperfine frequency comparisons

    CERN Document Server

    Hees, A; Abgrall, M; Bize, S; Wolf, P

    2016-01-01

    We use six years of accurate hyperfine frequency comparison data of the dual Rubidium and Caesium cold atom fountain FO2 at LNE-SYRTE to search for a massive scalar dark matter candidate. Such a scalar field can induce harmonic variations of the fine structure constant, of the mass of fermions and of the quantum chromodynamic mass scale, which will directly impact the Rubidium/Caesium hyperfine transition frequency ratio. We find no signal consistent with a scalar dark matter candidate but provide improved constraints on the coupling of the putative scalar field to standard matter. Our limits are complementary to previous results that were only sensitive to the fine-structure constant, and improve them by more than an order of magnitude when only a coupling to electromagnetism is assumed.

  13. Negative hydrogen ion production mechanisms

    Science.gov (United States)

    Bacal, M.; Wada, M.

    2015-06-01

    Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

  14. Contributions by emissions from nuclear installations to concentrations of radionuclides in milk

    CERN Document Server

    Green, N

    1983-01-01

    A year-long study has been carried out to determine whether milk produced near nuclear sites contains concentrations of radionuclides that can be attributed to discharges from the installations, and, as a consequence, whether there is enhanced exposure of those members of the public who consume this milk. Eight creameries were chosen and monthly samples of milk were taken for analysis. The concentrations of caesium-137 and strontium-90 were measured and compared with results from a national survey conducted as part of the Board's environmental radioactivity surveillance programme. No effect attributable to discharges from the nuclear establishments was identified. The activity concentrations ranged between 0.1 and 3 times the national average; the variation relates mainly to rainfall in the area, although other factors may also have an effect. However, milk contributes only a small fraction of the total dietary intake of caesium-137 and strontium-90, and so the exposure of persons consuming the milk varies on...

  15. Searching for an Oscillating Massive Scalar Field as a Dark Matter Candidate Using Atomic Hyperfine Frequency Comparisons

    Science.gov (United States)

    Hees, A.; Guéna, J.; Abgrall, M.; Bize, S.; Wolf, P.

    2016-08-01

    We use 6 yrs of accurate hyperfine frequency comparison data of the dual rubidium and caesium cold atom fountain FO2 at LNE-SYRTE to search for a massive scalar dark matter candidate. Such a scalar field can induce harmonic variations of the fine structure constant, of the mass of fermions, and of the quantum chromodynamic mass scale, which will directly impact the rubidium/caesium hyperfine transition frequency ratio. We find no signal consistent with a scalar dark matter candidate but provide improved constraints on the coupling of the putative scalar field to standard matter. Our limits are complementary to previous results that were only sensitive to the fine structure constant and improve them by more than an order of magnitude when only a coupling to electromagnetism is assumed.

  16. Rydberg atoms in hollow-core photonic crystal fibres

    CERN Document Server

    Epple, G; Euser, T G; Joly, N Y; Pfau, T; Russell, P St J; Löw, R

    2014-01-01

    The exceptionally large polarisability of highly excited Rydberg atoms (six orders of magnitude higher than ground-state atoms) makes them of great interest in fields such as quantum optics, quantum computing, quantum simulation and metrology. If however they are to be used routinely in applications, a major requirement is their integration into technically feasible, miniaturised devices. Here we show that a Rydberg medium based on room temperature caesium vapour can be confined in broadband-guiding kagome-style hollow-core photonic crystal fibres. Three-photon spectroscopy performed on a caesium-filled fibre detects Rydberg states up to a principal quantum number of n = 40. Besides small energy level shifts we observe narrow lines confirming the coherence of the Rydberg excitation. Using different Rydberg states and core diameters we study the influence of confinement within the fibre core after different exposure times. Understanding these effects is essential for the successful future development of novel ...

  17. High temperature behaviour of thermoelectric power of implanted polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, C.; Ratier, B.; Moliton, A.; Francois, B. [LEPOFI, Faculte des Sciences, Limoges (France)]|[Institut Charles Sadron, Strasbourg (France)

    1995-12-31

    The results of thermopower S measurements performed on implanted polyparaphenylene and polyimide films between 150 K and 450 K are presented. The implantations of Caesium or Iodine ions in polyparaphenylene with low parameters induce a sign of S characteristic to chemical nature of the implanted ions and an increase of lSl at around 350 K due to a transition from a VRH process to a polaronic conduction. With Iodine implanted sample at higher energy (E = 250 keV) and low dose (D = 2 x 10{sup 15} ions/cm{sup 2}) a transition from p type to n type doping at 400 K is attributed to a migration of negative oxygen ions as in the case of polyimide samples implanted with Caesium and Iodine ions where a similar behaviour of S is found. (Author).

  18. Dicaesium diaqua-bis-(methyl-ene-diphospho-nato-κO,O')cobaltate(II).

    Science.gov (United States)

    van Merwe, Kina; Visser, Hendrik G; Venter, Johan A

    2011-10-01

    The asymmetric unit of the title compound, Cs(2)[Co(CH(4)O(6)P(2))(2)(H(2)O)(2)], is comprised of one bidentate methyl-enediphospho-nate ligand and one water mol-ecule which are coordinated to the Co(II) atom, as well as a caesium counter-cation. The Co atom occupies a special position on a crystallographic inversion center. The caesium ion is octa-hedrally coordinated by six O atoms with Cs-O distances ranging from 3.119 (2) to 3.296 (2) Å. A three-dimensional network is formed through O-H⋯O hydrogen bonds.

  19. Avoiding Panic and Keeping the Ports Open in a Chemical and Biological Threat Environment. A Literature Review

    Science.gov (United States)

    2005-06-01

    socially branded as contaminated and thus to be avoided. For example, in 1987 a number of the residents of Goiania , Brazil, were exposed to radiation from...caesium chloride. As news of the exposure spread “Hotels in other parts of the country refused to allow Goiania residents to register, airline...pilots refused to fly with Goiania residents on board, automobiles driven by Goianians were stoned” and sales of Goianian products dropped

  20. Radioactive Waste in the Nordic and Far East Seas; a Soviet Legacy with International Environmental and National Security Repercussions

    Science.gov (United States)

    1994-01-01

    content of caesium-137 radionucleides did not exceed their natural levels. 69 14 However, researchers were not allowed to get closer than 30 miles to...was dependent on the specific radionucleides . Plutonium adheres to the ocean sediment, and is only accessible to benthic marine organisms; strontium...90 is highly mobile, and would be available to plankton and salmon. Radionucleides are subject to the ocean dilution factor and natural decay over

  1. The incident at Siderurgica Sevillana S. A.; El incidente de Siderurgica Sevilla S. A.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    With the information available at the date of publication, this article gives a summary of the incident at the plant of the company Siderurgica Sevillana S. A., in Alcala de Guadaira (province of Seville) in which a Caesium 137 source was melted down. The article also describes the measures adopted at the CSN's initiative and the extent to which they have been implemented. Lastly an initial assessment of given of the incident's radiological consequences. (Author)

  2. Application of the zoning decree in the medical sector: external radiotherapy and curietherapy; Application de l'arrete zonage dans le domaine medical: Radiotherapie externe et curietherapie

    Energy Technology Data Exchange (ETDEWEB)

    Pierrat, N. [Service de physique medicale, Institut Curie, 26 rue d' Ulm, 75005 Paris (France)

    2008-07-01

    The author presents some requirements about access to external radiotherapy rooms and curietherapy rooms according the application of a decree requiring zoning for radiotherapy practices. She also indicates some technical characteristics (radioactive sources, authorized radioactivity level). As far as curietherapy is concerned, she makes a distinction between treatments with or without a source projector, and also (in the case with a source projector) between low dose rate with caesium 137, pulsed radiation with indium 192 and high dose rate with indium 192

  3. METHODOLOGY OF INTERNAL DOSE RECONSTRUCTION FOR THE RUSSIAN POPULATION AFTER THE CHERNOBYL ACCIDENT

    Directory of Open Access Journals (Sweden)

    M. I. Balonov

    2008-01-01

    Full Text Available The paper presents methodology of the internal dose reconstruction from I-131 and caesium radionuclides received by population of Russia after the Chernobyl accident. The direct measurements of radionuclides content in a human body were the most relevant data for internal dose reconstruction. Assessment of radionuclides intake with food products was considered as the second priority and application of radioecological models as the third priority when measurement data were absent.

  4. Electroweak Precision Data - Global Higgs Analysis

    CERN Document Server

    Grünewald, M W

    2003-01-01

    The status of published and preliminary precision electroweak measurements as of winter 2002/03 is presented. The new results on the mass of the W boson as measured at LEP-2 and on atomic parity violation in Caesium are included. The experimental results are compared with the predictions of the minimal Standard Model and are used to constrain its parameters, including the mass of the Higgs boson. The agreement between measurements and expectations from theory is discussed.

  5. Mineral resource of the month: cesium

    Science.gov (United States)

    Angulo, Marc A.

    2010-01-01

    The article offers information on cesium, a golden alkali metal derived from the Latin word caesium which means bluish gray. It mentions that cesium is the first element discovered with the use of spectroscopy. It adds that the leading producer and supplier of cesium is Canada and there are 50,000 kilograms of cesium consumed of the world in a year. Moreover, it states that only 85% of the cesium formate can be retrieved and recycled.

  6. First testing of the CALIFA Barrel Demonstrator

    Science.gov (United States)

    Pietras, B.; Winkel, M.; Alvarez-Pol, H.; Bendel, M.; Casarejos, E.; Cederkäll, J.; Cortina-Gil, D.; Fernandez, G.; Gernhäuser, R.; Golubev, P.; González, D.; Hartig, A.; Izquierdo, P.; Klenze, P.; Le Bleis, T.; Nácher, E.; Perea, A.; Remmels, P.; Ribeiro, G.; Teubig, P.; Vilan, J.; Yañez, P.

    2016-04-01

    Advancement of the CALIFA calorimeter project has reached a new milestone with the construction of the first modules of the CALIFA Demonstrator, ultimately to be integrated into the final calorimeter. Aspects and methods of detector optimisation will be discussed, along with characterisation using proton beams of 70 caesium iodide quenching over the available proton energy range has been performed, to accompany a method for proton calibration scaled from the measured gamma-ray energies.

  7. Electronic Structures and Magnetic Properties of CoN, NiN and CuN

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-Bo; XUE De-Sheng

    2004-01-01

    @@ Electronic structures and magnetic properties of CoN, NiN and CuN in zinc-blende, rocksalt, nickel arsenide,wurtzite and caesium chloride structures have been calculated by employing a first-principle full-potential linearized muffin-tin orbital method with the generalized gradient approximation. The results reveal that the zinc-blende structure is the ground state for the three mononitrides.

  8. Status of non-destructive bunch length measurement based on coherent Cherenkov radiation

    CERN Document Server

    Zhang, Jianbing; Yu, Tiemin; Deng, Haixiao; Shkitov, Dmitry; Shevelev, Mikhail; Naumenko, Gennady; Potylitsyn, Alexander

    2013-01-01

    As a novel non-destructive bunch length diagnostic of the electron beam, an experimental observation of the coherent Cherenkov radiation generated from a dielectric caesium iodide crystal with large spectral dispersion was proposed for the 30MeV femtosecond linear accelerator at Shanghai Institute of Applied Physics (SINAP). In this paper, the theoretical design, the experimental setup, the terahertz optics, the first angular distribution observations of the coherent Cherenkov radiation, and the future plans are presented.

  9. Decay curve analysis of alkali-silicate glass exposed to electrons

    CERN Document Server

    Gedeon, O

    2002-01-01

    Binary and ternary potassium, rubidium and caesium glasses were irradiated by an electron beam with energy varying from 10 to 50 keV. Alkali ion x-ray decays were recorded and afterward incubation periods were determined. The incubation period versus electron energy curves revealed thresholds, which are typical for each alkali species. The threshold ratios are proportional to the mass of the alkali species, consistent with the suggested elastic scattering assisted hopping mechanism. (author)

  10. Experimental Test of Alternating-Current Zeeman Interference Effect in Ramsey Separated Oscillating Fields

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-Hai; WANG Feng-Zhi; YANG Dong-Hai

    2004-01-01

    An experimental test of ac Zeeman effect in an optically pumped caesium beam frequency standard is reported and analysed. An interference pattern of the atomic energy level shift as a function of the applied microwave field near the atomic transition frequency was observed. It was superimposed on the dispersion lineshape of a normal ac Zeeman effect. This effect was analysed with the atomic wavefunction phase analysing method.

  11. Dependence of electromagnetically induced transparency on temperature

    Institute of Scientific and Technical Information of China (English)

    Xiao Feng; Guo Rui-Min; Li Lu-Ming; Yang Dong-Hai; Chen Xu-Zong

    2004-01-01

    @@ We performed an experimental study on the dependence of the linewidth of electromagetically induced transparency (EIT) on the temperature of medium in a A-type configuration using caesium vapour. We found that the transparent window is narrowed in the EIT whose two ground levels are composed of two hyperfine levels, and broadened in the case when the two ground levels are degenerated Zeeman sublevels, as the temperature of vapour cell is increased. The explanation for the phenomena is given qualitatively.

  12. Application of Electron-Shelving Detection via 423 nm Transition in Calcium-Beam Optical Frequency Standard

    Institute of Scientific and Technical Information of China (English)

    HUANG Kai-Kai; ZHANG Jian-Wei; YU De-Shui; CHEN Zhen-Hui; ZHUAN Wei; CHEN Jing-Biao

    2006-01-01

    A new scheme of small compact optical frequency standard based on thermal calcium beam with application of 423 nm shelving detection and sharp-angle velocity selection detection is proposed. Combining these presented techniques, we conclude that a small compact optical frequency standard based on thermal calcium beam will outperform the commercial caesium-beam microwave clock, like the 5071 Cs clock (from HP to Agilent, now Symmetricom company), both in accuracy and stability.

  13. Experimental Research of Spontaneous Evolution from Ultracold Rydberg Atoms to Plasma

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lin-Jie; FENG Zhi-Gang; LI An-Ling; ZHAO Jian-Ming; LI Chang-Yong; JIA Suo-Tang

    2008-01-01

    @@ The spontaneous evolution from ultracold Rydberg atoms to plasma is investigated in a caesium MOT by using the method of field ionization. The plasma transferred from atoms in different Rydberg states (n = 22-32) are obtained experimentally. Dependence of the threshold time of evolving to plasma and the threshold number of initial Rydberg atoms on the principal quantum number of initial Rydberg states is studied. The experimental results are in agreement with hot-cold Rydberg-Rydberg atom collision ionization theory.

  14. Atom gravimeters and gravitational redshift

    CERN Document Server

    Wolf, Peter; Borde, Christian J; Reynaud, Serge; Salomon, Christophe; Cohen-Tannoudji, Claude; 10.1038/nature09340

    2010-01-01

    In a recent paper, H. Mueller, A. Peters and S. Chu [A precision measurement of the gravitational redshift by the interference of matter waves, Nature 463, 926-929 (2010)] argued that atom interferometry experiments published a decade ago did in fact measure the gravitational redshift on the quantum clock operating at the very high Compton frequency associated with the rest mass of the Caesium atom. In the present Communication we show that this interpretation is incorrect.

  15. Pn/sup +/ junction in an implanted electroactive polymer: poly(paraphenylene)

    Energy Technology Data Exchange (ETDEWEB)

    Moliton, A.; Duroux, J.L.; Ratier, B.; Froyer, G.

    1988-03-31

    We have recently shown that specific and stable n or p doping may be obtained on poly(paraphenylene) providing moderate implantation conditions with appropriate ions are used. Here we describe a pn/sup +/-junction made in intrinsic insulating poly(paraphenylene) (sigma < 10/sup -12/ ..cap omega../sup -1/ cm/sup -1/) by implantation (E approx. = 50 keV) of alkali metal ions (essentially caesium for n doping) and halogen (iodine for p doping).

  16. Evaluation of the neutral comet assay for detection of alpha-particle induced DNA-double-strand-breaks; Evaluation des Comet Assays bei neutralem pH zur Detektion von α-Partikel induzierten DNA-Doppelstrangbruechen

    Energy Technology Data Exchange (ETDEWEB)

    Hofbauer, Daniela

    2010-10-20

    Aim of this study was to differentiate DNA-double-strand-breaks from DNA-single-strand-breaks on a single cell level, using the comet assay after α- and γ-irradiation. Americium-241 was used as a alpha-irradiation-source, Caesium-137 was used for γ-irradiation. Because of technical problems with both the neutral and alkaline comet assay after irradiation of gastric cancer cells and human lymphocytes, no definite differentiation of DNA-damage was possible.

  17. [Presence of autocomplementary RNA with viral specificity in cells infected with herpes virus].

    Science.gov (United States)

    Béchet, J M; Montagnier, L; Latarjet, R

    1975-01-13

    RNA from cells infected with Herpes simplex virus contain a higher percentage of double-stranded RNA than non-infected cells. This percentage increases three-fold upon self-annealing. The complementary RNA sequences were shown to be virus-specific by the following criteria: (1) high melting temperature than double-stranded RNA from non infected cells; (2) higher density in caesium sulphate; (3) specific hybridization with viral DNA.

  18. The IRSN publishes an assessment of doses received in Japan by external irradiation due to radioactive deposits caused by the Fukushima-Daiichi power plant accident; L'IRSN publie une estimation des doses recues au Japon par irradiation externe due aux depots radioactifs provoques par l'accident de la centrale de Fukushima-Daiichi

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This document first describes how dry and wet radioactive deposits are formed. It also indicates their main components: iodine 131 and 132, caesium 134, 136 and 137, tellurium 132, and barium 140. It describes the different exposure ways due to radioactive deposits in the environment. A map indicates dose level assessments few tens of kilometres around the Fukushima power plant. A brief comment of this map is proposed

  19. Assessment of the consequences of the Fukushima accident on the environment in Japan, one year after the accident; Bilan des consequences de l'accident de Fukushima sur l'environnement au Japon, un an apres l'accident

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-02-28

    Illustrated by several maps and figures, this document proposes and discusses quantitative assessments of radioactive releases in the air (rare gases, iodine, tellurium compounds, caesium), of the atmospheric dispersion of releases, of the contamination of soils by radioactive deposits (dry and humid deposits), of the contamination of food products in Japan (vegetable productions, animal productions like meat, milk, eggs and so on), and of the contamination of the marine environment

  20. [Behavior of fuel hot particles in the body of cows at oral intake].

    Science.gov (United States)

    Kashparov, V A; Lazarev, N M; Ioshchenko, V I

    1997-01-01

    It was studied the behaviour of fuel hot particles (analogous to Chernobyl) in gastrointestinal tract of cows. The values of caesium and strontium radionuclides transfer to the cows organism and its transition parameters to milk after the single per oral intake to the organism of animals are estimated. It is shown, that the biological simplicity of radionuclides in the fuel hot particles at two parameters lower, than the same radionuclides in washed phases.

  1. Modelling of radionuclide migration in forest ecosystems. A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Avila, R.; Moberg, L.; Hubbard, L.

    1998-03-01

    The Chernobyl accident has clearly shown the long-term effects of a radioactive contamination of forest ecosystems. This report is based on a literature review of models which describe the migration of radionuclides, radioactive caesium in particular, in forest ecosystems. The report describes the particularities of the forest ecosystem, the time dynamics of the contamination, the transfer processes and factors influencing caesium migration. This provides a basis for a discussion of different approaches for modelling caesium migration in the forest. It is concluded that the studied dynamic models include the most relevant transfer processes both for the acute and the long-term phase after a radioactive deposition. However, most models are site specific and do not consider some of the factors responsible for the differences in radionuclide behaviour and distribution in different types of forests. Although model improvements are constrained by the availability of experimental data and by the lack of knowledge of the migration mechanisms some possible improvements are discussed. This report is part of the LANDSCAPE project. -An integrated approach to radionuclide flow in the semi-natural ecosystems underlying exposure pathways to man. 42 refs, 3 tabs, 9 figs.

  2. Detection of Fukushima Daiichi nuclear power plant accident radioactive traces in Monaco.

    Science.gov (United States)

    Pham, M K; Eriksson, M; Levy, I; Nies, H; Osvath, I; Betti, M

    2012-12-01

    Daily air monitoring of radionuclides in the Principality of Monaco (43°73'N, 7°43'E) after the Fukushima Daiichi nuclear power plant accident showed that only Iodine-131 ((131)I) and Caesium isotopes ((134)Cs and (137)Cs) were detected. The peak of (131)I varied and reached its maximum between March 29th and April 5th, meanwhile both peaks of (134)Cs and (137)Cs arrived later and attained a maximum between April 1st and 4th. Their maximum activity concentrations in air were 354, 30, and 37 μBq m(-3) respectively. The (134)Cs to (137)Cs activity ratio was close to 1, which is different from that one observed after the Chernobyl accident (around 0.54). Up to 95% of caesium isotopes were washed out by wet scavenging during 27-28th of March, where the maximum deposition rates of (134)Cs and (137)Cs (13.7 and 19.1 mBq m(-2) day(-1), respectively) were observed. The significant input of (134)Cs and (137)Cs into the Mediterranean seawater column (30 m depth) was detected later, on the 24th of May. Radioisotopes of caesium and iodine were found far above the applied detection limits, but still with no concern for harmful radiation exposure and public health. The contamination gradually decreased in air and activity concentrations returned to background values after one or two months.

  3. Development of a laboratory method to predict rapidly the availability of radiocaesium

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, D.L.; Livens, F.R.; Beresford, N.A.; Howard, B.J.; Barnett, C.L. (Institute of Terrestrial Ecology, Grange-on-Sands (United Kingdom). Merlewood Research Station); Mayes, R.W. (Macaulay Land Use Research Inst., Roslin (United Kingdom)); Segal, M.G. (Ministry of Agriculture, Fisheries and Food, London (United Kingdom))

    1992-03-01

    A simple extraction procedure has been developed to assess rapidly the probable extent of the transfer of radiocaesium into ruminant food products soon after a nuclear accident. The in vitro extractions were validated against true absorption measurements of different forms of radiocaesium in the sheep gut. Extractions were performed on a range of different radiocaesium sources. Some of these sources were artificial (ionic radiocaesium adsorbed onto bentonite, silica spheres and filter-papers) and others were environmentally contaminated (silt from the Ravenglass Estuary contaminated by effluent from British Nuclear Fuels Limited (BNFL) Sellafield, and upland grass and heather contaminated by Chernobyl fallout). Laboratory experiments concentrated primarily on the use of simple inorganic extractants in competitive ion-exchange processes. Of the reagents used, 0.1 mol dm{sup -3} stable caesium chloride solution was the most effective extractant. The proportion of radiocaesium extracted by 0.1 mol dm{sup -3} caesium chloride correlated well with measurements of true absorption. Extracting radiocaesium using 0.1 mol dm{sup -3} caesium chloride proved to be an inexpensive and rapid method of predicting the availability of radiocaesium for absorption in the ruminant gut, giving results within 24 h. Further extractions were carried out using cellulase/pepsin simulated digestions and ovine rumen fluid. Results suggested that the availability of radiocaesium from some inorganic sources may be underestimated using such techniques. (author).

  4. Development of a laboratory method to predict rapidly the availability of radiocaesium.

    Science.gov (United States)

    Singleton, D L; Livens, F R; Beresford, N A; Howard, B J; Barnett, C L; Mayes, R W; Segal, M G

    1992-03-01

    A simple extraction procedure has been developed to assess rapidly the probable extent of the transfer of radiocaesium into ruminant food products soon after a nuclear accident. The in vitro extractions were validated against true absorption measurements of different forms of radiocaesium in the sheep gut. Extractions were performed on a range of different radiocaesium sources. Some of these sources were artificial (ionic radiocaesium adsorbed onto bentonite, silica spheres and filter-papers) and others were environmentally contaminated [silt from the Ravenglass Estuary contaminated by effluent from British Nuclear Fuels Limited (BNFL) Sellafield, and upland grass and heather contaminated by Chernobyl fallout]. Laboratory experiments concentrated primarily on the use of simple inorganic extractants in competitive ion-exchange processes. Of the reagents used, 0.1 mol dm-3 stable caesium chloride solution was the most effective extractant. The proportion of radiocaesium extracted by 0.1 mol dm-3 caesium chloride correlated well with measurements of true absorption. Extracting radiocaesium using 0.1 mol dm-3 caesium chloride proved to be an inexpensive and rapid method of predicting the availability of radiocaesium for absorption in the ruminant gut, giving results within 24 h. Further extractions were carried out using cellulase/pepsin simulated digestions and ovine rumen fluid. Results suggested that the availability of radiocaesium from some inorganic sources may be underestimated using such techniques.

  5. Progress of the ELISE test facility: towards one hour pulses in hydrogen

    Science.gov (United States)

    Wünderlich, D.; Fantz, U.; Heinemann, B.; Kraus, W.; Riedl, R.; Wimmer, C.; the NNBI Team

    2016-10-01

    In order to fulfil the ITER requirements, the negative hydrogen ion source used for NBI has to deliver a high source performance, i.e. a high extracted negative ion current and simultaneously a low co-extracted electron current over a pulse length up to 1 h. Negative ions will be generated by the surface process in a low-temperature low-pressure hydrogen or deuterium plasma. Therefore, a certain amount of caesium has to be deposited on the plasma grid in order to obtain a low surface work function and consequently a high negative ion production yield. This caesium is re-distributed by the influence of the plasma, resulting in temporal instabilities of the extracted negative ion current and the co-extracted electrons over long pulses. This paper describes experiments performed in hydrogen operation at the half-ITER-size NNBI test facility ELISE in order to develop a caesium conditioning technique for more stable long pulses at an ITER relevant filling pressure of 0.3 Pa. A significant improvement of the long pulse stability is achieved. Together with different plasma diagnostics it is demonstrated that this improvement is correlated to the interplay of very small variations of parameters like the electrostatic potential and the particle densities close to the extraction system.

  6. Distribution characteristics of 137Cs in wind-eroded soil profile and its use in estimating wind erosion modulus

    Institute of Scientific and Technical Information of China (English)

    HU Yunfeng; LIU Jiyuan; ZHUANG Dafang; CAO Hongxia; YAN Huimin; YANG Fengting

    2005-01-01

    Due to its inert reaction in soil system and distinctive vertical distribution in soil profile, caesium-137 (137Cs) has been used as a tracer to assess wind erosion. In this study, 62 soil samples were collected from 4 sampling sites in Taipusi County, Inner Mongolia; Caesium-137 activities for those soil samples were measured using a gamma-ray spectrometry in Sichuan University, Chengdu. Distribution pattern of 137Cs in vertical soil profile was different for different land use and land cover types. Caesium-137 was distributed homogeneously in plow layer of cropland, and negatively exponential in low to medium cover grassland. Distribution pattern in high covered grassland was represented by a peak at 2-4 cm soil depth followed by a negative exponential curve. Based on those findings, simplified mass balance model was chosen to estimate the rate of wind erosion for cropland, while profile distribution model was used for grassland. Estimated wind erosion rates were 7990, 4270 and dium cover grassland, respectively. Wind erosion intensity correlated negatively with plant cover.

  7. {sup 40}K/{sup 137}Cs discrimination ratios to the aboveground organs of tropical plants

    Energy Technology Data Exchange (ETDEWEB)

    Sanches, N. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Niteroi, CEP 24210-346, RJ (Brazil); Anjos, R.M. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Niteroi, CEP 24210-346, RJ (Brazil)], E-mail: meigikos@if.uff.br; Mosquera, B. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Niteroi, CEP 24210-346, RJ (Brazil)

    2008-07-15

    In the present work, the accumulation of caesium and potassium in aboveground plant parts was studied in order to improve the understanding on the behaviour of monovalent cations in several compartments of tropical plants. We present the results for activity concentrations of {sup 137}Cs and {sup 40}K, measured by gamma spectrometry, from five tropical plant species: guava (Psidium guajava), mango (Mangifera indica), papaya (Carica papaya), banana (Musa paradisiaca), and manioc (Manihot esculenta). Caesium and potassium have shown a high level of mobility within the plants, exhibiting the highest values of concentration in the growing parts (fruits, leaves, twigs, and barks) of the woody fruit and large herbaceous shrub (such as manioc) species. In contrast, the banana and papaya plants exhibited the lowest levels of {sup 137}Cs and {sup 40}K in their growing parts. However, a significant correlation between activity concentrations of {sup 137}Cs and {sup 40}K was observed in these tropical plants. The {sup 40}K/{sup 137}Cs discrimination ratios were approximately equal to unity in different compartments of each individual plant, suggesting the possibility of using caesium to predict the behaviour of potassium in several tropical species.

  8. RADIATION CONDITIONS IN KALUGA REGION 30 YEARS AFTER CHERNOBYL NPP ACCIDENT

    Directory of Open Access Journals (Sweden)

    A. G. Ashitko

    2016-01-01

    Full Text Available The article describes radiation conditions in the Kaluga region 30 years after the Chernobyl NPP accident. The Chernobyl NPP accident caused radioactive contamination of nine Kaluga region territories: Duminichsky, Zhizdrinsky, Kuibyshevsky, Kirovsky, Kozelsky, Ludinovsky, Meshchovsky, Ulyanovsky and Hvastovichsky districts. Radioactive fallout was the strongest in three southern districts: Zhizdrinsky, Ulyanovsky and Hvastovichsky, over there cesium-137 contamination density is from 1 to 15Ci/km. According to the Russian Federation Government Order in 2015 there are 300 settlements (S in the radioactive contamination zone, including 14 settlements with caesium-137 soil contamination density from 5 to 15 Ci/ km2 and 286 settlements with the contamination density ranging from 1 to 5 Ci/km2. In the first years after the Chernobyl NPP accident in Kaluga region territories, contaminated with caesium-137, there were introduced restrictive land usage, were carried out agrochemical activities (ploughing, mineral fertilizer dressing, there was toughened laboratory radiation control over the main doze-forming foodstuff. All these measures facilitated considerable decrease of caesium-137 content in local agricultural produce. Proceeding from the achieved result, in 2002 there took place the transition to more tough requirements SanPiN 2.3.2.1078-01. Analysis of investigated samples from Zhizdrinsky, Ulyanovsky and Hvastovichsky districts demonstrated that since 2005 meat samples didn’t exceed the standard values, same for milk samples since 2007. Till the present time, the use of wild-growing mushrooms, berries and wild animals meat involves radiation issues. It was demonstrated that average specific activity of caesium-137 in milk samples keeps decreasing year after year. Long after the Chernobyl NPP accident, the main products forming internal irradiation doses in population are the wild-growing mushrooms and berries. Population average annual

  9. Interaction of calcium silicate hydrates (C-S-H), the main components of cement, with alkaline chlorides, analogy with clays; Interaction des silicates de calcium hydrates, principaux constituants du ciment, avec les chlorures d'alcalins. Analogie avec les argiles

    Energy Technology Data Exchange (ETDEWEB)

    Viallis-Terrisse, H

    2000-10-06

    This work, belonging to a more general study on the structure and reactivity of cement, deals with the experimental and theoretical analysis of the interaction of alkaline chlorides with calcium silicate hydrates (C-S-H), the main components of cement paste. The interaction of alkaline cations with C-S-H is interfacial, involving both electrostatic and surface complexation mechanisms. The C-S-H surface is constituted of silanol sites, partially dissociated due to the high pH of the interstitial solution. The calcium ions, present in large amounts in the equilibrium solution of C-S-H, constitute potential determining ions for the C-S-H surface. The alkaline ions seem to compete with calcium for the same surface sites. The adsorption isotherms show that caesium presents a better affinity than sodium and lithium for the C-S-H surface. Moreover, solid-state NMR suggests that caesium forms with the surface sites inner-sphere complexes, whereas sodium seems to keep its hydration sphere. These results are in agreement with zeta potential measurements, which let suppose a specific adsorption of caesium ions, and an indifferent behaviour of both other alkaline ions. A model for the C-S-H surface was proposed, from the electric double layer model, and mass action laws expressing the complexation of the different ionic species with the silanol sites. The whole study relies on a structural analogy with smectites, some clays presenting well-known cationic adsorption properties. The structural similarity between both minerals is enhanced by some similarities of reactivity, though significant behaviour differences could also be noted. (author)

  10. Absolute frequency measurement of the {{}^{1}}{{\\text{S}}_{0}} – {{}^{3}}{{\\text{P}}_{0}} transition of 171Yb

    Science.gov (United States)

    Pizzocaro, Marco; Thoumany, Pierre; Rauf, Benjamin; Bregolin, Filippo; Milani, Gianmaria; Clivati, Cecilia; Costanzo, Giovanni A.; Levi, Filippo; Calonico, Davide

    2017-02-01

    We report the absolute frequency measurement of the unperturbed transition {{}1}{{\\text{S}}0} – {{}3}{{\\text{P}}0} at 578 nm in 171Yb realized in an optical lattice frequency standard relative to a cryogenic caesium fountain. The measurement result is 518 295 836 590 863.59(31) Hz with a relative standard uncertainty of 5.9× {{10}-16} . This value is in agreement with the ytterbium frequency recommended as a secondary representation of the second in the International System of Units.

  11. Absolute frequency measurement of the 1S0 - 3P0 transition of 171Yb

    CERN Document Server

    Pizzocaro, Marco; Rauf, Benjamin; Bregolin, Filippo; Milani, Gianmaria; Clivati, Cecilia; Costanzo, Giovanni A; Levi, Filippo; Calonico, Davide

    2016-01-01

    We report the absolute frequency measurement of the unperturbed transition 1S0 - 3P0 at 578 nm in 171Yb realized in an optical lattice frequency standard. The absolute frequency is measured 518 295 836 590 863.55(28) Hz relative to a cryogenic caesium fountain with a fractional uncertainty of 5.4x10-16 . This value is in agreement with the ytterbium frequency recommended as a secondary representation of the second in the International System of Units.

  12. A magnetic guide for cold atoms

    CERN Document Server

    Richmond, J A; Cantwell, B P; Opat, G I

    1998-01-01

    We propose a novel method for guiding cold, neutral atoms using static magnetic fields. A theoretical study of the magnetic field produced by a tube consisting of two identical, interwound solenoids carrying equal but opposite currents is presented. This field is almost zero throughout the centre of the tube, but it increases with exponential rapidity as one approaches the walls formed by the current carrying wires. Hence, cold atoms passing through the tube may be reflected by magnetic mirror effects near the walls. Applying this technique to a free-falling cloud of magneto-optically cooled caesium atoms we hope to construct atomic guides to facilitate the manipulation of cold atomic beams.

  13. Fundamental approach to the design of a dose-rate calculation program for use in brachytherapy planning

    Energy Technology Data Exchange (ETDEWEB)

    Cassell, K.J. (Saint Luke' s Hospital, Guildford (UK))

    1983-02-01

    A method, developed from the Quantisation Method, of calculating dose-rate distributions around uniformly and non-uniformly loaded brachytherapy sources is described. It allows accurate and straightforward corrections for oblique filtration and self-absorption to be made. Using this method, dose-rate distributions have been calculated for sources of radium 226, gold 198, iridium 192, caesium 137 and cobalt 60, all of which show very good agreement with existing measured and calculated data. This method is now the basis of the Interstitial and Intracavitary Dosimetry (IID) program on the General Electric RT/PLAN computerised treatment planning system.

  14. Electroanalytical studies of some species of clinical importance

    OpenAIRE

    Diaz, Martin Telting

    1990-01-01

    Solvent polymeric membrane electrodes incorporating p-t-butyl hexaethyl ester and hexaethyl ester calix[6 ]arene as neutral carriers have been constructed for use in caesium selective electrodes. The potentiometric sensing electrodes including 2-nitrophenyloctyl ether as solvent mediator exhibit near-Nernstian behaviour in the range 1x10 M to 1x10 M CsCl. The pattern of selectivity encountered for a range of common interferents is not modified by the inclusion of potassium tetrakis(p-ch!oroph...

  15. Bayesian feedback control of a two-atom spin-state in an atom-cavity system

    CERN Document Server

    Brakhane, Stefan; Kampschulte, Tobias; Martinez-Dorantes, Miguel; Reimann, René; Yoon, Seokchan; Widera, Artur; Meschede, Dieter

    2012-01-01

    We experimentally demonstrate real-time feedback control of the joint spin-state of two neutral Caesium atoms inside a high finesse optical cavity. The quantum states are discriminated by their different cavity transmission levels. A Bayesian update formalism is used to estimate state occupation probabilities as well as transition rates. We stabilize the balanced two-atom mixed state, which is deterministically inaccessible, via feedback control and find very good agreement with Monte-Carlo simulations. On average, the feedback loops achieves near optimal conditions by steering the system to the target state marginally exceeding the time to retrieve information about its state.

  16. Desorption Techniques for Determination of Metals Mobility in Soils

    Directory of Open Access Journals (Sweden)

    P. Bartoš

    2002-01-01

    Full Text Available Three leaching techniques for assessment of fixed and mobile metal or radionuclides in soils are demonstrated on radiocaesium speciation. A new leaching technique based on the variation of the leaching solution volume to solid phase amount is proposed. It enables parallel treatment of large numbers of samples and, therefore, is suitable for a routine analysis of contaminant mobility in soils. As a leaching solution, 1 M ammonium acetate is proposed for caesium, but any other desorption solution harmonised with existing speciation schemes can be used.

  17. Single Cs Atoms as Collisional Probes in a large Rb Magneto-Optical Trap

    CERN Document Server

    Weber, Claudia; Spethmann, Nicolas; Meschede, Dieter; Widera, Artur

    2010-01-01

    We study cold inter-species collisions of Caesium and Rubidium in a strongly imbalanced system with single and few Cs atoms. Observation of the single atom fuorescence dynamics yields insight into light-induced loss mechanisms, while both subsystems can remain in steady-state. This significantly simplifies the analysis of the dynamics, as Cs-Cs collisions are effectively absent and the majority component remains unaffected, allowing us to extract a precise value of the Rb-Cs collision parameter. Extending our results to ground state collisions would allow to use single neutral atoms as coherent probes for larger quantum systems.

  18. Hexacyanoferrates and bentonite as binders of radiocaesium for reindeer

    Directory of Open Access Journals (Sweden)

    Knut Hove

    1991-10-01

    Full Text Available The effects of varying doses of caesium binders (Bentonite and several forms of iron-hexacyanoferrates on radiocaesium accumulation in red blood cells and on radiocaesium transfer to urine and faeces were studied in feeding experiments with reindeer calves. The caesium binders were added to a ration of lichen (containing 9.5 kBq of 134Cs+137Cs originating from the Chernobyl accident and fed together with a pelleted reindeer feed (RF-71 for 42 days. A 50% reduction in red blood cell radiocaesium concentration was obtained with a daily dose of 1 mg/kg body weigth of ammoniumironhexacyanoferrate (AFCF and with 500 mg/kg of bentonite. Three mg/kg of AFCF or 2 g/kg of bentonite reduced both urinary excretion and RBC concentrations with more than 80%. It is concluded that iron-hexacyanoferrates, as a result of their high caesium binding capacity, are particularly useful as caesium binders for free ranging ruminants like the reindeer.Hexacynoferrater og bentonitt som bindere av radiocesium i reinAbstract in Norwegian / Sammendrag: Effekten av bentonitt og ulike typer jernhexacyanoferrater (Berlinerblått på akkumulering av radioaktivt cesium i røde blodlegemer og på utskilling av radioaktivt cesium i urin ble undersøkt i foringsforsøk med reinkalver. Cesiumbinderne ble gitt daglig sammen med lav som inneholdt 9.5 kBq 134Cs+137Cs fra Tsjernobyl ulykken, og 1 kg reinfor (RF-71 i en periode på 42 dager. En daglig dose på 1 mg/kg kroppsvekt av ammoniumjernhexacyano-ferrat (AFCF reduserte radiocesiuminnholdet i blodlegemer med 50%, mens en dose pa 500 mg/kg bentonitt var nødvendig for å oppnå samme effekt. Tre mg/kg AFCF eller 2 g/kg/bentonitt var nødvendig for å oppnå mer enn 80% reduksjon i radiocesium konsentrasjonen i blodlegemer og i radiocesium utskilling med urinen. På grunn av de små daglige mengder som kreves er jern-hexacyanoferratene spesielt velegnete som cesiumbindere for beitedyr.

  19. First principles calculations of the ground state properties and structural phase transformation in YN

    CERN Document Server

    Mancera, L; Takeuchi, N

    2003-01-01

    We have studied the structural and electronic properties of YN in rock salt (sodium chloride), caesium chloride, zinc blende and wurtzite structures using first-principles total energy calculations. Rock salt is the calculated ground state structure with a = 4.93 A, B sub 0 = 157 GPa. The experimental lattice constant is a = 4.877 A. There is an additional local minimum in the wurtzite structure with total energy 0.28 eV/unit cell higher. At high pressure (approx 138 GPa), our calculations predict a phase transformation from a NaCl to a CsCl structure.

  20. Progress of the NTSC-F1 primary frequency standard

    Institute of Scientific and Technical Information of China (English)

    RUAN; Jun; WANG; Xinliang; LIU; Dandan; GUAN; Yong; ZHANG; Hui; CHEN; Jiang; LIN; Rui; YU; Fengxiang; SHI; Junru; ZHANG; Shougang

    2015-01-01

    The SI "second"is realized by caesium primary frequency standards( PFSs) using laser cooled atoms in a fountain configuration. Four sub systems and operation procedure of the NTSC-F1 primary frequency standard are introduced in the paper.The frequency stability of NTSC-F1 is 3.0×10-13/ τ-1 / 2compared to hydrogen maser. Four terms of frequency shift and uncertainty including second order Zeeman frequency shift,cold collision shift,gravity shift and blackbody shift are evaluated. The improvement of NTSC-F1 is introduced.

  1. Cs5Sn9(OH·4NH3

    Directory of Open Access Journals (Sweden)

    Ute Friedrich

    2014-06-01

    Full Text Available The title compound, pentacaesium nonastannide hydroxide tetraammonia, crystallized from a solution of CsSnBi in liquid ammonia. The Sn94− unit forms a monocapped quadratic antiprism. The hydroxide ion is surrounded by five caesium cations, which form a distorted quadratic pyramidal polyhedron. A three-dimensional network is formed by Cs—Sn [3.8881 (7 Å to 4.5284 (7 Å] and Cs—NH3 [3.276 (7–3.636 (7 Å] contacts.

  2. A new functional for charge and mass identification in Delta E-E telescopes

    CERN Document Server

    Tassan-Got, L

    2002-01-01

    We propose a new functional for the charge and mass identification in Delta E-E telescopes. This functional is based on Bethe's formula, allowing safe interpolation or extrapolation in regions with low statistics. When applied to telescopes involving detectors delivering a linear response, as silicon detectors or ionization chambers, a good mass and charge identification is achieved. For other detectors, as caesium-iodide used as a final member of a telescope, a good accuracy is also obtained except in the low residual energy region. A good identification is however recovered if a non-linear energy dependence of the light output is included.

  3. Experimental investigation of the sub-Doppler transmission spectroscopy in a thin vapour layer at room temperature

    Institute of Scientific and Technical Information of China (English)

    Zhao Yan-Ting; Zhao Jian-Ming; Huang Tao; Xiao Lian-Tuan; Jia Suo-Tang

    2004-01-01

    The sub-Doppler transmission spectrum in a thin vapour layer (about 150μm) was observed at room temperature using the wavelength modulation technology. The absorption signal and its second-order harmonic were detected with an external-cavity diode laser. A sub-Doppler spectrum corresponding to resonant transitions of the caesium D2 line(6S1/2 →6P3/2) was demonstrated. The dependence of the transmission signal on the intensity of the laser was also investigated.

  4. A new functional for charge and mass identification in $\\Delta$ E-E telescopes

    CERN Document Server

    Tassan-Got, L

    2001-01-01

    We propose a new functional for the charge and mass identification in $\\Delta$E-E telescopes. This functional is based on the Bethe formula, allowing safe interpolation or extrapolation in regions with low statistics. When applied to telescopes involving detectors delivering a linear response, as silicon detectors or ionization chambers, a good mass and charge identification is achieved. For other detectors, as caesium-iodide used as a final member of a telescope, a good accuracy is also obtained except in the low residual energy region. A good identification is however recovered if a non-linear energy dependence of the light output is included.

  5. Improved frequency measurement of the $^1S_{0}$-$^3P_{0}$ clock transition in $^{87}$Sr using the Cs fountain clock at NMIJ as a transfer oscillator

    CERN Document Server

    Tanabe, Takehiko; Kobayashi, Takumi; Takamizawa, Akifumi; Yanagimachi, Shinya; Ikegami, Takeshi; Suzuyama, Tomonari; Inaba, Hajime; Okubo, Sho; Yasuda, Masami; Hong, Feng-Lei; Onae, Atsushi; Hosaka, Kazumoto

    2015-01-01

    We performed an absolute frequency measurement of the $^1S_{0}$-$^3P_{0}$ transition in $^{87}$Sr with a fractional uncertainty of $1.2 \\times 10^{-15}$, which is less than one third that of our previous measurement. A caesium fountain atomic clock was used as a transfer oscillator to reduce the uncertainty of the link between a strontium optical lattice clock and the SI second. The absolute value of the transition frequency is 429 228 004 229 873.56(49) Hz.

  6. Cold Atom Physics Using Ultra-Thin Optical Fibers: Light-Induced Dipole Forces and Surface Interactions

    CERN Document Server

    Sagu'e, G; Meschede, D; Rauschenbeutel, A; Vetsch, E

    2007-01-01

    The strong evanescent field around ultra-thin unclad optical fibers bears a high potential for detecting, trapping, and manipulating cold atoms. Introducing such a fiber into a cold atom cloud, we investigate the interaction of a small number of cold Caesium atoms with the guided fiber mode and with the fiber surface. Using high resolution spectroscopy, we observe and analyze light-induced dipole forces, van der Waals interaction, and a significant enhancement of the spontaneous emission rate of the atoms. The latter can be assigned to the modification of the vacuum modes by the fiber.

  7. Realization of Optical Phase Locked Loop at 9.2 GHz between Two Independent Diode Lasers

    Institute of Scientific and Technical Information of China (English)

    LI Lu-Ming; TANG Wen-Zhuo; HU Zhen-Yan; GUO Hong

    2008-01-01

    The optical-phase-locked-loop (OPLL) at 9.2 GHz between two independent narrow linewidth diode lasers is realized. Ultrabroad servo bandwidth at 4 MHz is first achieved and it is guaranteed that the full spectral characteristics of the master laser can be transferred to the slave laser. The experimental results prove that the coherence between two lasers is about 99%. This offers a new method to study the interaction between lasers and atoms based on the ground hyperfine structure of caesium atoms.

  8. Experimental investigation of slow light propagation in degenerate two-level system

    Institute of Scientific and Technical Information of China (English)

    Wang Li-Rong; Zhao Yan-Ting; Ma Jie; Zhao Jian-Ming; Xiao Lian-Tuan; Jia Suo-Tang

    2006-01-01

    Slowing a light pulse in a degenerate two-level system is observed with a double-frequency sweeping technique. The effects of coupling beam intensity, cell temperature and frequency detunings of the coupling and probe beams in resonance, on the slowing of light propagation in such a system are investigated. It is found that group velocities depend strongly on polarization combinations. A group velocity υg=6760m/s of light pulses in caesium vapour is obtained under the optimal parameters.

  9. Natural perovskite: (CaII0.95 (1CeIII0.011 (2NaI0.010 (4(FeIII0.022 (2TiIV0.98 (1O3

    Directory of Open Access Journals (Sweden)

    Nelson G. Fernandes

    2008-09-01

    Full Text Available A natural sample of perovskite (calcium caesium sodium iron titanium oxide from the Tapira Alkaline Complex in southeastern Brazil was found by electron microprobe analysis to have the chemical formula (Ca2+0.95 (1Ce3+0.011 (2Na+0.010 (4(Fe3+0.022 (2Ti4+0.98 (1O2−3 and by IR spectroscopy to be an anhydrous mineral. Oxygen anions are arranged around Ti4+ in an almost perfect octahedron and around Ca2+ in a distorted 12-fold polyhedron.

  10. Artificial Neural Network and Response Surface Methodology Modeling in Ionic Conductivity Predictions of Phthaloylchitosan-Based Gel Polymer Electrolyte

    Directory of Open Access Journals (Sweden)

    Ahmad Danial Azzahari

    2016-01-01

    Full Text Available A gel polymer electrolyte system based on phthaloylchitosan was prepared. The effects of process variables, such as lithium iodide, caesium iodide, and 1-butyl-3-methylimidazolium iodide were investigated using a distance-based ternary mixture experimental design. A comparative approach was made between response surface methodology (RSM and artificial neural network (ANN to predict the ionic conductivity. The predictive capabilities of the two methodologies were compared in terms of coefficient of determination R2 based on the validation data set. It was shown that the developed ANN model had better predictive outcome as compared to the RSM model.

  11. Analysis of the iodine gas phase produced by interaction of CsI and MoO{sub 3} vapours in flowing steam

    Energy Technology Data Exchange (ETDEWEB)

    Gouello, M. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SEREX/L2EC, PSN-RES/SAG/LETR, Cadarache, St. Paul-lez-Durance 13115 (France); Mutelle, H., E-mail: herve.mutelle@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SEREX/L2EC, PSN-RES/SAG/LETR, Cadarache, St. Paul-lez-Durance 13115 (France); Cousin, F. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SEREX/L2EC, PSN-RES/SAG/LETR, Cadarache, St. Paul-lez-Durance 13115 (France); Sobanska, S. [Laboratoire de Spectrochimie IR et Raman, UMR-CNRS 8516, CERLA FR-CNRS 2416 Université de Lille 1, 59655 Villeneuve d’Ascq (France); Blanquet, E. [Laboratoire de Science et Ingénierie des Matériaux et Procédés, Grenoble INP, UJF, CNRS, 1130 rue de la Piscine, 38402 St. Martin d’Heres (France)

    2013-10-15

    Highlights: • Reactions between MoO{sub 3} and CsI vapours in flowing steam produce gaseous iodine. • Fraction of gaseous iodine increases within a short range of the Mo/Cs molar ratio. • Caesium molybdates were identified under condensed form by Raman spectroscopy. • Iodine gas speciation is better accounted with a kinetically limited scheme. -- Abstract: In case of severe accident in a water-cooled nuclear reactor, the amount of gaseous iodine released from the primary circuit is of particular concern because it can have a direct impact on the short-term iodine source term to the environment. As revealed by the Phebus FPT tests, assessment of the iodine forms at the break is a complex issue that requires to take into account not only the thermal and flow conditions in the circuit but also the behaviour of several elements such as caesium and molybdenum involved in iodine chemistry at high temperature. Moreover, reactions between these elements and with the carrier gas could be kinetically-limited due to the low concentrations and the short residence time of the fission products in the primary circuit coupled to the strong thermal gradients encountered in this part of the reactor. In order to reduce the uncertainties in the fraction of gaseous iodine, experimental and modelling studies have been launched in the framework of the international CHIP program. The work presented in this paper is part of this program and aims to investigate the effect of molybdenum using an open flow reactor where MoO{sub 3} and CsI vapours are injected under steam/argon atmosphere. In these conditions, the experiments clearly demonstrate that molybdenum increases the fraction of gaseous iodine released at low temperature and show that this effect is highly sensitive to the Mo/Cs ratio. Caesium polymolybdates identified in the solid state by Raman microspectroscopy are consistent with the species of the Cs{sub 2}MoO{sub 4}–MoO{sub 3} diagram suggesting that some part of

  12. Dicaesium tetrachloridodioxidoplutonate(VI

    Directory of Open Access Journals (Sweden)

    Marianne P. Wilkerson

    2008-01-01

    Full Text Available The anion of the title complex, Cs2[PuCl4O2], adopts a pseudo-octahedral geometry (2/m crystallographic site symmetry with two plutonyl oxide ligands in axial sites and four chloride ligands occupying the equatorial plane. Charge balance is maintained by two caesium cations per tetrachloridodioxidoplutonate(VI anion. Principal bond lengths include Pu—O = 1.752 (3 Å and Pu—Cl = 2.6648 (8 Å.

  13. 2,9,12,15,18,25,27,34,37,40,43,50-Dodecaoxa-56-azaheptacyclo[24.24.5.151,55.03,8.019,24.028,33.044,49]hexapentaconta-3,5,7,19(24,20,22,28(33,29,31,44,46,48,51,53,55-pentadecaene

    Directory of Open Access Journals (Sweden)

    Jun Hee Kim

    2012-10-01

    Full Text Available The title compound, C43H45NO12, was prepared from the reaction of 2,6-bis(dibromomethylpyridine and bisphenol in the presence of caesium carbonate as a base. The central ring makes dihedral angles of 64.83 (6, 13.48 (6, 56.96 (6 and 66.21 (6° with the peripheral rings. In the crystal, molecules are linked by weak C—H...O and C—H...π interactions, forming a folded structure.

  14. Negative Ion Sources: Magnetron and Penning

    CERN Document Server

    Faircloth, D C

    2013-01-01

    The history of the magnetron and Penning electrode geometry is briefly outlined. Plasma generation by electrical discharge-driven electron impact ionization is described and the basic physics of plasma and electrodes relevant to magnetron and Penning discharges are explained. Negative ions and their applications are introduced, along with their production mechanisms. Caesium and surface production of negative ions are detailed. Technical details of how to build magnetron and Penning surface plasma sources are given, along with examples of specific sources from around the world. Failure modes are listed and lifetimes compared.

  15. Monitoring Australia's Northern Coastline in Advance of Signs from Fukushima

    Energy Technology Data Exchange (ETDEWEB)

    Grzechnik, Marcus P.; Bokor, Ilonka; Urban, David A.; Carpenter, Julia G.; Hirth, Gillian A. [Australian Radiation Protection and Nuclear Safety Agency, 619 Lower Plenty Road, Yallambie, Victoria, 3084 (Australia)

    2014-07-01

    Australia has the third largest marine estate of any nation in the world, with a total area of 3.1 million square kilometres of ocean managed primarily for biodiversity conservation as marine reserves. Regular offshore radiological monitoring of the entire Australian coastline is impractical because of its size, however several projects currently under way at the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) to target areas where background monitoring of caesium ({sup 134}Cs and {sup 137}Cs) could be useful. Of particular interest to ARPANSA and the Australian Public are; - Radiological discharges due to the Japanese nuclear accident, 2011, and their potential effects on Australian seas and aquatic wildlife. - Visits to Australia from Nuclear Powered Warships (NPWs). Significant oceanic discharges from the Fukushima Dai-ichi Nuclear Power Plant (in excess of 3.6 PBq {sup 137}Cs) are expected to be dispersed over a number of years. For long term global dispersion, a transit time of about 5 years (i.e. arrival in 2016) has been estimated for radioactive material to reach the northern coast of Western Australia, and about 10 to 15 years to reach the eastern coast of Queensland. It is expected that radioactive material from the Japan accident will have been diluted to such a degree that it will be difficult to detect in Australian waters, however there is limited information on current caesium levels in water and biota to use as a background (or baseline) level. This is also the case for the Australian Ports where NPWs have permission to berth. This paper will describe several projects currently underway at ARPANSA aimed at determining background caesium levels in seawater and aquatic wildlife, as well as detailing future monitoring programmes intended to gather information to demonstrate the protection of the Australian public and aquatic environment. Background levels of caesium that have been collated since the project began in 2012 will also

  16. Precision spectroscopy of hydrogen and femtosecond laser frequency combs.

    Science.gov (United States)

    Hänsch, T W; Alnis, J; Fendel, P; Fischer, M; Gohle, C; Herrmann, M; Holzwarth, R; Kolachevsky, N; Udem, Th; Zimmermann, M

    2005-09-15

    Precision spectroscopy of the simple hydrogen atom has inspired dramatic advances in optical frequency metrology: femtosecond laser optical frequency comb synthesizers have revolutionized the precise measurement of optical frequencies, and they provide a reliable clock mechanism for optical atomic clocks. Precision spectroscopy of the hydrogen 1S-2S two-photon resonance has reached an accuracy of 1.4 parts in 10(14), and considerable future improvements are envisioned. Such laboratory experiments are setting new limits for possible slow variations of the fine structure constant alpha and the magnetic moment of the caesium nucleus mu(Cs) in units of the Bohr magneton mu(B).

  17. Automated separation process for radioanalytical purposes at nuclear power plants.

    Science.gov (United States)

    Nagy, L G; Vajda, N; Vodicska, M; Zagyvai, P; Solymosi, J

    1987-10-01

    Chemical separation processes have been developed to remove the matrix components and thus to determine fission products, especially radioiodine nuclides, in the primary coolant of WWER-type nuclear reactors. Special procedures have been elaborated to enrich long-lived nuclides in waste waters to be released and to separate and enrich caesium isotopes in the environment. All processes are based mainly on ion-exchange separations using amorphous zirconium phosphate. Automated equipment was constructed to meet the demands of the plant personnel for serial analysis.

  18. Nucleation in an ultra low ionization environment

    DEFF Research Database (Denmark)

    Pedersen, Jens Olaf Pepke; Enghoff, Martin Andreas Bødker; Paling, Sean

    filter in order to reduce the Radon concentration. In this way we have been able to make nucleation experiments with very low ionizing background, meaning that we can rule out ion induced nucleation as a contributing mechanism. Our experimental setup is a 50 L electropolished stainless steel reactor...... at near atmospheric conditions. The chamber contains clean air with the addition of water vapour, ozone, and SO2. Using UV lights at 254 nm ozone is photolyzed, leading to the production of sulphuric acid and thus aerosols. An 18 MBq Caesium-137 gamma ray source with various amounts of lead in front...

  19. Vertical distribution of radiocaesium, plutonium and americium in the Catalan Sea (northwestern Mediterranean)

    Energy Technology Data Exchange (ETDEWEB)

    Molero, J.; Sanchez-Cabeza, J.A.; Merino, J.; Pujol, Ll.; Vidal-Quadras, A. [Universidad Autonoma de Barcelona (Spain). Facultad de Ciencias; Mitchell, P.I. [University Coll., Dublin (Ireland). Lab. of Radiation Physics

    1995-07-01

    Caesium-137, {sup 239,240}Pu and {sup 241}Am concentration profiles (0-1000 m) have been determined in unfiltered large volume water samples collected from the Catalan Sea (northwestern Mediterranean). Results showed that radiocaesium concentration decreases quickly through the water column while the transuranic concentration increases with depth, showing a faster migration to the bottom layers. Comparing our results with those reported by other authors (1975-1980), radiocaesium input from Chernobyl releases has been identified through the profile. In addition, transuranic concentrations have decreased considerably in the different layers of the profile. (Author).

  20. Leakage investigation at Shalamar Garden, Lahore using radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, S.D.; Mustafa, N.; Khan, N.A. (Pakistan Inst. of Nuclear Science and Technology, Rawalpindi)

    1982-02-01

    A sealed caesium-137 radiation source and 73 injections of sodium-24 in water soluble form have been successfully employed to detect leakage points and determine the layout pattern of a terracotta pipeline grid feeding the decorative fountains of the central tank in the middle terrace of Shalamar Garden, Lahore. The pipeline system is about 350 years old and no drawing or layout plan was available before the studies. The present investigation is an effort to help restore the original historic water supply system.

  1. Huelva (phosphogypsum and Cs 137 wastes). Radiological controls on phosphogypsum storage lagoons and of the CRI-9 dump. Measurement of the external exposure. Soil, wastes and water radiological characterization; Huelva (phosphogypse et dechets Cs 137). Controles radiologiques sur les lagunes de stockage de phosphogypse et la decharge CRI-9. Mesure de l'exposition externe. Caracterisation radiologique des sols, dechets et eau

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-11-15

    This document reports radiological measurements and sampling performed in lagoons where phosphogypsum wastes coming from the Huelva industrial complex are stored. All samples (soils, sediments, solid wastes, waters) were analysed by high resolution gamma spectrometry. First, the authors analyse and report the impact of phosphogypsum storages through on-site gamma radiation measurements and through laboratory analyses. Then they report the assessment of the impact of a specific dump where caesium 137 contaminated wastes are present since an accident which occurred in the Acerinox factory. Some recommendations are given to solve the radioprotection problems created by these storages

  2. Ab initio calculations of yttrium nitride: structural and electronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Zerroug, S.; Ali Sahraoui, F. [Universite Ferhat Abbas, Laboratoire d' Optoelectronique et Composants, Departement de Physique, Setif (Algeria); Bouarissa, N. [King Khalid University, Department of Physics, Faculty of Science, P.O. Box 9004, Abha (Saudi Arabia)

    2009-11-15

    Using first principles total energy calculations within the full-potential linearized augmented plane wave method, we have studied the structural and electronic properties of yttrium nitride (YN) in the three phases, namely wurtzite, caesium chloride and rocksalt structures. The calculations are performed at zero and under hydrostatic pressure. In agreement with previous findings, it is found that the favored phase for YN is the rocksalt-like structure. We predict that at zero pressure YN in the rocksalt structure is a semiconductor with an indirect bandgap of 0.8 eV. A phase transition from a rocksalt to a caesium chloride structure is found to occur at {proportional_to}134 GPa. Besides, a transition from an indirect ({gamma}-X) bandgap semiconductor to a direct (X-X) one is predicted at pressure of {proportional_to}84 GPa. For the electron effective mass of rocksalt YN, these are the first results, to our knowledge. The information derived from the present study may be useful for the use of YN as an active layer in electronic devices such as diodes and transistors. (orig.)

  3. [Measurement of linear exposure nominal pose used in curietherapy].

    Science.gov (United States)

    Bernard, M; Guille, B; Duvalet, G

    1975-11-01

    The idea, and subsequent construction, of a dose rate meter for measuring linear exposure dose originated in those pilot centres of Curietherapie which wished to replace radium by the artificial radionucleides, Irdium-192, Caesium-137 etc. The aparatus makes it possible to measure, directly and quickly, the activity of a specified length of a linear source, a measurement which has only been possible until now by dividing the exposure dose by the length whose activity it is desired to know. If the dose-rate obtained by these two methods agrees, this apparatus shortens the time for which the sources need to be handled, thereby reducing the danger of irradiation to staff and technicians. The apparatus is thus able to reveal heterogeneity of activity along the length of a line-source. In the specific case of Iridium, our experience shows that wires which have been used in several applications may develop mechanical bends and constrictions, which can lead to fluctuation in dose rate along their length. The apparatus was first constructed in 1967, after preliminary experiments in 1965. As Curietherapy has become more widely used, the apparatus has undergone many modifications which is more precise and specific than it was initially. At the present time it can only be used with Iridium as wire, and with Caesium in the form of trains of seeds (corresponding to the AGS sources) or needles. Nevertheless, a third scale is under consideration, for use with newer radioelements, which may be used in future.

  4. Chernobyl; Tchernobyl

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report relates the Chernobylsk accident, why following a succession of technical malfunctions and human errors, reactor no. 4 of the Chernobylsk nuclear power plant explodes on April 26. 1986. Radioactive dust, aerosols and gases (including caesium and iodine) are ejected into atmosphere. The regions worst hit are in the immediate vicinity of the plant, but deposits are very uneven, producing a leopard spot type of pattern. Propelled by easterly winds, the radioactive cloud disperses increasingly, scattering deposits over the whole of Europe. At the beginning of May, the cloud arrives in France. the eastern portion of the country is most strongly affected. Ground, water and agriculture are contaminated by caesium deposits in Belarus, Ukraine and Russian Federation. About the contamination in France, ground contamination is slight, fourteen years later, however, it is still detectable. Relative to the impact on health in the vicinity of Chernobylsk plant, it is hard to assess this impact. Among children in Southern Belarus, the number of thyroid cancers has risen one hundred-fold. In France, the doses delivered represents generally less than 1% of the average annual dose from radioactivity of natural origin. But some of the doses received were higher. Today, the protective sarcophagus covering the damaged reactor is fragile. Reactor no.3, still in operation, continues to pose a risk but the shutdown is provided for december 2000. (N.C.)

  5. Chernobyl-what do we need to know?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    Following a succession of technical malfunctions and human errors, reactor No.4 of Chernobyl nuclear power plant explodes on April 26, 1986. Radioactive dust, aerosols, and gases (including iodine and caesium) are ejected into the atmosphere. The regions worst hit are in the immediate vicinity of the plant (Belarus, Ukraine) but deposits are very uneven, producing a 'leopard spot' type of pattern (Russian Federation). In Europe, propelled by easterly winds, the radioactive cloud disperses increasingly, scattering deposits over the whole Europe. At the beginning of May, the cloud arrives over France. The eastern portion of the country is most strongly affected. For the contamination, ground, water, and agriculture are contaminated by caesium deposits in Belarus, Ukraine and Russian Federation. In France, ground contamination is slight, fourteen years later, however, it is still detectable. It is hard to assess the impact on health in the vicinity of the Chernobyl plant; among children in southern Belarus, the number of thyroid cancers has risen one hundred-fold. The doses delivered in France represent generally less than 1% of the average annual dose from radioactivity of natural origin. But some of the doses received were higher. Today, the protective sarcophagus covering the damaged reactor is fragile. Reactor No.3, still in operation, continues to pose a risk but the shutdown is provide for december 2000. (N.C.)

  6. Polonium 210, an important natural reference for radiological protection; Le polonium 210, un repere naturel important en radioprotection

    Energy Technology Data Exchange (ETDEWEB)

    Pradel, J.; Zettwoog, P.; Dellero, N.; Beutier, D. [Cogema, 78 - Velizy Villacoublay (France)

    2001-12-01

    Natural polonium 210 which has a relatively short decay period (138 days) and is uranium decay series daughter should retain more radiological attention because it induces chronic doses higher than that of traces of caesium 137 and plutonium isotopes (238, 239, 240) in the environment. In the earth's crust, uranium is present together with radium, radon and its daughter products, at a concentration of about 40,000 Bq t{sup -1}. As a consequence of radon 222 exhalation from soils within a metric layer and of lead 210 (radon daughter) fall-down, there is an enrichment of polonium 210 radioactivity in top layer soil relatively to radium concentration, within a factor varying from 2.7 to 8.8 according to environmental measurements. Human exposure to polonium 210 by ingestion is not negligible. The induced exposure by ingestion of natural polonium 210 is 30 to 70 limes higher than that of caesium from Chernobyl fall-down at Helsinki in 1986. Moreover, the latter decreases in relation with the 30 years' decay period while that from radon daughters remains. Comparison with plutonium shows a 500 to 2,000 times stronger health effect by ingestion for the same number of deposited becquerels on soil. 'Hot spots' may occur in the environment: polonium 210 is particularly concentrated by marine fauna, as shown by several measurement programs over the ares of north-east Atlantic. (author)

  7. The consequences of the Chernobyl accident in the Ukraine and problems with the sarcophagus; Die Folgen der Katastrophe von Tschernobyl in der Ukraine und die Probleme mit dem Sarkophag

    Energy Technology Data Exchange (ETDEWEB)

    Kopchinsky, G.A. [Atomaudit, Kiew (Ukraine)

    1996-07-01

    The reactor accident in the Ukraine contaminated part of the territory with iodine 131, caesium 137, strontium 90, and plutonium 239 and 240. The zone surrounding the site of the accident was declared restricted area; more than 90 000 persons were evacuated. The paper reports on current conditions in the restricted area and prospects for this area as well as on the current state of, and problems with, the sarcophagus. The conversion of the sarcophagus into an ecologically safe system and the economic situation of the Ukraine pose great problems. (DG) [Deutsch] Durch den Reaktorunfall in der Ukraine ist ein Teil des Territoriums mit Jod 131, Caesium 137, Strontium 90, Plutonium 239 und -240 kontaminiert worden. Um den Unfallort wurde eine Isolierungszone geschaffen und mehr als 90.000 Menschen evakuiert. Ueber den Zustand und die Perspektiven der Isolierungszone sowie ueber den Zustand und die Probleme des Sarkophags wird berichtet. Die Umgestaltung des Sarkophags in ein oekologisch sicheres System und die wirtschaftliche Situation der Ukraine bereiten grosse Probleme. (DG)

  8. Reports from the Bavarian State Agency for Environmental Protection (6). Technical reports. Information from LfU; Berichte aus dem Bayerischen Landesamt fuer Umweltschutz (6). Fachbeitraege. Informationen aus dem LfU

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    In 1993 again, the Bavarian State Agency for Environmental protection had a broad range of tasks to fulfill. They form the subject of the 29 contributions. Described is not only the monitoring of radioactive and non-radioactive environmental pollutants but also the extension of the nuisance measuring grid. The cooperation with Russia in the southern Ural regarding the in-vivo determination of strontium 90 and caesium 137 in exposed persons is dealt with. The section `reports from LfU` covers also projects in the areas of nature conservation and care of the landscape. (DG) [Deutsch] Das bayerische LfU hatte auch im Jahr 1993 umfangreiche Aufgaben zu erfuellen. Die 29 Berichte geben hierueber einen Ueberblick, wobei neben der Erfahrung radioaktiver und nichtradioaktiver Umweltschadstoffe auch der Ausbau des Immissionsmessnetzes beschrieben wird. Auf die Zusammenarbeit mit Russland im Suedural in Bezug der In-vivo-Bestimmung von Strontium 90 und Caesium 137 an exponierten Personen wird eingegangen. Die Mitteilungen aus dem LfU umfassen auch Projekte auf dem Gebiet des Naturschutzes und der Landschaftspflege. (DG)

  9. Rydberg atoms in hollow-core photonic crystal fibres

    Science.gov (United States)

    Epple, G.; Kleinbach, K. S.; Euser, T. G.; Joly, N. Y.; Pfau, T.; Russell, P. St. J.; Löw, R.

    2014-06-01

    The exceptionally large polarizability of highly excited Rydberg atoms—six orders of magnitude higher than ground-state atoms—makes them of great interest in fields such as quantum optics, quantum computing, quantum simulation and metrology. However, if they are to be used routinely in applications, a major requirement is their integration into technically feasible, miniaturized devices. Here we show that a Rydberg medium based on room temperature caesium vapour can be confined in broadband-guiding kagome-style hollow-core photonic crystal fibres. Three-photon spectroscopy performed on a caesium-filled fibre detects Rydberg states up to a principal quantum number of n=40. Besides small energy-level shifts we observe narrow lines confirming the coherence of the Rydberg excitation. Using different Rydberg states and core diameters we study the influence of confinement within the fibre core after different exposure times. Understanding these effects is essential for the successful future development of novel applications based on integrated room temperature Rydberg systems.

  10. Soil characterization and vulnerability indices of the autonomous region of Madrid. Scale 1:200 000; Caracterizacion Edafologica e Indices de Vulnerabilidad de la Comunidad Autonoma de Madrid Escala 1:200.000

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, T.; Millan, R.; Lago, C.; Trueba, C. [Ciemat. Madrid (Spain)

    2000-07-01

    Radioactive contamination of the soil due to a nuclear accident is a risk for the population. A research project, within the program of Radiological Protection by Intervention in CIEMAT, has been developed to study the behaviour of radionuclides in soils. An evaluation of the radiological vulnerability considering the external irradiation and the food chain pathway for caesium and strontium has been determined using partial and global indices, which indicate the potential transfer of the radionuclides via the two mentioned pathways. A detailed study of the soils found in the Autonomous Region of Madrid was carried out with data from individual soil profiles and combining data obtained from maps with a Geographic Information System in order to obtain a spatial distribution of the results. The soil vulnerability for the external irradiation pathway of caesium and strontium is in general found to be higher in more developed soils located in the south and leading to the foothills of the Sierra of Madrid in the north. the vulnerability for the food chain pathway is found to be higher in the less developed soils in acid conditions situated in the Sierra of Madrid. (Author) 11 refs.

  11. The incorporation of radiolabelled sulphur from captan into protein and its impact on a DNA binding study.

    Science.gov (United States)

    Provan, W M; Eyton-Jones, H; Lappin, G; Pritchard, D; Moore, R B; Green, T

    1995-05-19

    Repeated administration of high doses of captan is known to produce tumours specifically in the duodenum of mice. Captan is not carcinogenic in the rat. In this study, DNA purified from the liver, stomach, duodenum and jejenum of mice dosed with 35S radiolabelled captan was found to contain radioactivity equivalent to Covalent Binding Indices in the range 38-91; that from the bone marrow had a CBI of 2.8. The distribution of radioactivity between the various tissues did not reflect the target organ specificity of captan. Attempts to further purify the DNA samples using caesium chloride gradients resulted in partial separation of the radioactivity from the DNA suggesting that covalent binding to the DNA may not have occurred. A study of the chemical breakdown of captan showed that captan is unstable, producing a variety of potentially reactive species containing sulphur. Evidence was further obtained to show that the sulphur of captan is incorporated into endogenous amino acids and protein. Hepatic DNA from mice dosed with 35S radiolabelled N-acetylcysteine, and two thiazolidine derivatives which are analogous to known metabolites of captan, was radiolabelled to a similar extent to that from captan treated mice. Furthermore, the DNA from each of these treatments had similar properties on caesium chloride gradients. It was concluded that the radioactivity associated with DNA in the captan DNA binding study was present in the low levels of protein which are always associated with purified DNA samples.

  12. Coherent population trapping resonances at lower atomic levels of Doppler broadened optical lines

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, E; Hamid, R; Çelik, M [National Metrology Institute of Turkey, Gebze, Kocaeli (Turkey); Özen, G [Istanbul Technical University, Faculty of Science and Letters, Engineering Physics Department Maslak, Istanbul (Turkey); Izmailov, A Ch [Institute of Physics, Azerbaijan National Academy of Sciences, H. Javid av. 33, Baku, Az-1143 (Azerbaijan)

    2014-11-30

    We have detected and analysed narrow high-contrast coherent population trapping (CPT) resonances, which are induced in absorption of a weak monochromatic probe light beam by counterpropagating two-frequency pump radiation in a cell with rarefied caesium vapour. The experimental investigations have been performed by the example of nonclosed three level Λ-systems formed by spectral components of the D{sub 2} line of caesium atoms. The applied method allows one to analyse features of the CPT phenomenon directly at a given low long-lived level of the selected Λ-system even in sufficiently complicated spectra of atomic gases with large Doppler broadening. We have established that CPT resonances in transmission of the probe beam exhibit not only a higher contrast but also a much lesser width in comparison with well- known CPT resonances in transmission of the corresponding two-frequency pump radiation. The results obtained can be used in selective photophysics, photochemistry and ultra-high resolution atomic (molecular) spectroscopy. (laser applications and other topics in quantum electronics)

  13. A Cs-Based Optical Frequency Measurement Using Cross-Linked Optical and Microwave Oscillators

    CERN Document Server

    Tamm, Chr; Lipphardt, B; Gerginov, V; Nemitz, N; Kazda, M; Weyers, S; Peik, E

    2013-01-01

    We describe a measurement of the frequency of the 2S1/2(F = 0) - 2D3/2(F' = 2) transition of 171Yb+ at the wavelength 436 nm (frequency 688 THz), using a single Yb+ ion confined in a Paul trap and two caesium fountains as references. In one of the fountains, the frequency of the microwave oscillator that interrogates the caesium atoms is stabilized by the laser that excites the Yb+ reference transition with a linewidth in the hertz range. The stability is transferred to the microwave oscillator with the use of a fiber laser based optical frequency comb generator that also provides the frequency conversion for the absolute frequency measurement. The frequency comb generator is configured as a transfer oscillator so that fluctuations of the pulse repetition rate and of the carrier offset frequency do not degrade the stability of the frequency conversion. The phase noise level of the generated ultrastable microwave signal is comparable to that of a cryogenic sapphire oscillator. For fountain operation with optic...

  14. Simultaneous Faraday filtering of the Mollow triplet sidebands with the Cs-D1 clock transition

    Science.gov (United States)

    Portalupi, Simone Luca; Widmann, Matthias; Nawrath, Cornelius; Jetter, Michael; Michler, Peter; Wrachtrup, Jörg; Gerhardt, Ilja

    2016-11-01

    Hybrid quantum systems integrating semiconductor quantum dots (QDs) and atomic vapours become important building blocks for scalable quantum networks due to the complementary strengths of individual parts. QDs provide on-demand single-photon emission with near-unity indistinguishability comprising unprecedented brightness--while atomic vapour systems provide ultra-precise frequency standards and promise long coherence times for the storage of qubits. Spectral filtering is one of the key components for the successful link between QD photons and atoms. Here we present a tailored Faraday anomalous dispersion optical filter based on the caesium-D1 transition for interfacing it with a resonantly pumped QD. The presented Faraday filter enables a narrow-bandwidth (Δω=2π × 1 GHz) simultaneous filtering of both Mollow triplet sidebands. This result opens the way to use QDs as sources of single as well as cascaded photons in photonic quantum networks aligned to the primary frequency standard of the caesium clock transition.

  15. Consequences of the Chernobyl accident for reindeer husbandry in Sweden

    Directory of Open Access Journals (Sweden)

    Gustaf Åhman

    1990-09-01

    Full Text Available Large parts of the reindeer hearding area in Sweden were contaminated with radioactive caesium from the Chernobyl fallout. During the first year after the accident no food with activity concentrations exceeding 300 Bq/kg was allowed to be sold in Sweden. This meant that about 75% of all reindeer meat produced in Sweden during the autumn and winter 1986/87 were rejected because of too high caesium activités. In May 1987 the maximum level for Cs-137 in reindeer, game and fresh-water fish was raised to 1500 Bq/kg. During the last two year, 1987/88 and 1988/89, about 25% of the slaughtered reindeer has had activities exceeding this limit. The effective long-time halflife or radiocaesium in reindeer after the nuclear weapon tests in the sixties was about 7 years. If this halflife is correct also for the Chernobyl fallout it will take about 35 years before most of the reinder in Sweden are below the current limit 1500 Bq/kg in the winter. However, by feeding the animals uncontaminated food for about two months, many reindeer can be saved for human consumption.

  16. Synthesis and Characterization of Upconversion Fluorescent Yb3+, Er3+ Doped CsY2F7 Nano- and Microcrystals

    Directory of Open Access Journals (Sweden)

    Helmut Schäfer

    2009-01-01

    Full Text Available Cs Y2F7: 78%   Y3+, 20%   Yb3+, 2%   Er3+ nanocrystals with a mean diameter of approximately 8 nm were synthesized at   185°C in the high boiling organic solvent N-(2-hydroxyethyl-ethylenediamine (HEEDA using ammonium fluoride, the rare earth chlorides and a solution of caesium alkoxide of N-(2-hydroxyethyl-ethylenediamine in HEEDA. In parallel with this approach, a microwave assisted synthesis was carried out which forms nanocrystals of the same material, about 50 nm in size, in aqueous solution at 200∘C/8 bar starting from ammonium fluoride, the rare earth chlorides, and caesium fluoride. In case of the nanocrystals, derived from the HEEDA synthesis, TEM images reveal that the particles are separated but have a broad size distribution. Also an occurred heat-treatment of these nanocrystals (600∘C for 45 minutes led to bulk material which shows highly efficient light emission upon continuous wave (CW excitation at 978 nm. Besides the optical properties, the structure and the morphology of the three products were investigated by means of powder XRD and Rietveld method.

  17. 氢钟守时应用%Study on the usage of hydrogen clock in time keeping

    Institute of Scientific and Technical Information of China (English)

    屈俐俐

    2012-01-01

    Based on the second difference of the measured time-difference for the hydrogen clock,the frequency drift of hydrogen clock can be estimated and corrected.The corrected data for the hydrogen clock not only keep the good short-term stability but also show much better long-term stability which achieves or surpasses that of HP5071A caesium clock,a caesium clock with middle-upper level.Thus the contribution of hydrogen clock to the time scale kept in time laboratories can be enhanced if the method discussed in this paper is adopted.%通过对氢钟时差测量数据的二次差分,获得频率漂移的准确量值后对氢钟时差测量数据进行修正,经过频率漂移修正后的氢钟数据在保持其良好短稳特性的基础上长稳性能得到了较大提升,达到或超过性能中上的高性能管的商品铯钟5071A的常稳指标,这种处理方法能提高守时氢钟对时间实验室所保持的时间尺度的贡献。

  18. Experimenting an optical second with strontium lattice clocks

    CERN Document Server

    Targat, R Le; Coq, Y Le; Zawada, M; Guéna, J; Abgrall, M; Gurov, M; Rosenbusch, P; Rovera, D G; Nagórny, B; Gartman, R; Westergaard, P G; Tobar, M E; Lours, M; Santarelli, G; Clairon, A; Bize, S; Laurent, P; Lemonde, P; Lodewyck, J

    2013-01-01

    Progress in realizing the SI second had multiple technological impacts and enabled to further constraint theoretical models in fundamental physics. Caesium microwave fountains, realizing best the second according to its current definition with a relative uncertainty of 2-4x10^(-16), have already been superseded by atomic clocks referenced to an optical transition, both more stable and more accurate. Are we ready for a new definition of the second? Here we present an important step in this direction: our system of five clocks connects with an unprecedented consistency the optical and the microwave worlds. For the first time, two state-of-the-art strontium optical lattice clocks are proven to agree within their accuracy budget, with a total uncertainty of 1.6x10^(-16). Their comparison with three independent caesium fountains shows a degree of reproducibility henceforth solely limited at the level of 3.1x10^(-16) by the best realizations of the microwave-defined second.

  19. Installation for producing sealed radioactive sources; Installation de fabrication de sources radioactives scellees

    Energy Technology Data Exchange (ETDEWEB)

    Fradin, J.; Hayoun, C. [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    This installation has been designed and built for producing sealed sources of fission elements: caesium 137, strontium 90, promethium 147, ruthenium 106 and cerium 144 in particular. The installation consists of sealed and protected cells, each being assigned to a particular production. The safety and the operational reliability of the equipment are the principal considerations which have governed this work. The report describes the installation and, in particular, the apparatus used as well as the various control devices. In conclusion, a review as presented of six years operation. (authors) [French] Cette installation a ete concue et realisee pour effectuer des fabrications de sources scellees d'elements de fission: caesium 137 - strontium 90 - promethium 147 - ruthenium 106 - cerium 144 en particulier. L'installation est composee de cellules etanches et protegees, chacune d'elles etant affectee a une fabrication particuliere. La securite et la surete de fonctionnement de l'ensemble sont parmi les elements principaux qui ont guide l'etude. Le rapport decrit l'installation et plus particulierement l'appareillage utilise ainsi que les divers controles et commandes. Le bilan de fonctionnement apres 6 ans d'exploitation sert de conclusion. (auteurs)

  20. Contribution to the study of the behaviour, in the urban environment, during the runoff of rainwater, of the fission products emitted during a nuclear accident; Contribution a l`etude du devenir, en milieu urbain, pendant le ruissellement des eaux pluviales, des produits de fission emis en cas d`accident nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Pioch, M.

    1993-05-24

    In the context of research into the environmental consequences of a serious accident occurring on a pressurized water reactor, this paper concerns the experimental study of behaviour of five fission products (caesium, strontium, iodine, ruthenium and tellurium) in the urban environment under the action of rainwater. Stable or radioactive multiple-element aerosols were produced. Their physicochemical characteristics and their solubility in rainwater were studied. Caesium and rubidium forms solutions totally and quickly, while strontium is partially soluble (approximately 50 %) and iodine is only slightly soluble. The behaviour of fission products on five urban surfaces was then studied. Batch experiments showed that the retention of dissolved forms of radioelements varied according to the material. The reactions involved are ion exchange reactions. The presence of certain ions in water (in particular NH{sub 4}{sup +}) increase the desorption of radioelements. Using a laboratory rainfall simulator, the re-entrainment of fission products by rainwater was examined. Two modes of deposition and two intensities of rainfall were simulated. The desorption of radioelements is greater after wet deposition and remobilization is reduced by an increase in intensity of rainfall. An addition of NH{sub 4}{sup +} in water is especially effective in the case of wet depositions. Suggestions are made in order to improve experimental protocols and continue the research. (author). 75 refs., 51 figs., 69 tabs., 14 appends.

  1. {sup 63}Ni and {sup 137}Cs chemistry in the soil-plant system; Chimie de {sup 63}Ni et de {sup 137}Cs dans le systeme sol-plante

    Energy Technology Data Exchange (ETDEWEB)

    Pinel, F

    2002-06-01

    The treatment and storage of radioactive waste are the responsibility of the ANDRA (The french agency for the management of radioactive wastes). The impact to man, via the entry in the human food chain depends on the mobility of each radionuclide in soil, root uptake and the subsequent redistribution in the plant. The distribution coefficient, Kd, is thought to be a good, estimator of bioavailability. We have investigated a large number of plant species (11 for caesium and 7 for nickel) in contact with contrasting soils under controlled conditions. Nickel adsorption has also been measured under controlled conditions. Particular attention has been paid to the consequences of modification of soil properties in the rhizosphere. This study confirms that the value of Kd is a good indicator of bioavailability of both nickel and caesium and that the value of Kd measured in dilute suspension may be extrapolated to that under in situ conditions. The value of Kd depends on soil pH, solution ionic strength, the presence of complexing ligands and redox conditions. The differences observed between species in nickel uptake may often be related to changes in rhizosphere pH and parallel modifications in Kd. The translocation of nickel from roots to shoots for a given species depends on the conditions of growth, due in part to access to different pools of soil nickel. (author)

  2. Analysis of the Fukushima accident impact in France (mainland and overseas territories) from the results of the reinforced environmental radioactivity monitoring; Analyse de l'impact de l'accident de Fukushima en France (metropole et DROM-COM) a partir des resultats de la surveillance renforcee de la radioactivite de l'environnement

    Energy Technology Data Exchange (ETDEWEB)

    Chaptal-Gradoz, N.

    2011-07-01

    The enhanced environmental radioactivity monitoring settled in France (and the country's overseas territories) following the Fukushima Dai-ichi accident detected trace levels of the main radionuclides released into the atmosphere during the accident (iodine 131, caesium 134 and 137, and smaller quantities of tellurium 132) and monitored their evolution until May. In mainland France, the various measurement results relating to air, rainwater and terrestrial products revealed that no traces of radionuclides attributable to the Fukushima accident were detected prior to 24 March. Airborne particulate iodine 131 was detected for the first time in a sample collected on 24 March at the summit of the Puy-de-Dome mountain, and this observation was confirmed nationwide with effect from 25 March. In the other compartments of the environment, the first significant results for iodine 131 were obtained over the following days. The maximum iodine 131 levels detected were of the order of: - a few milli-becquerels per cubic metre of air (mBq/m{sup 3}); - approximately 10 becquerels per kilogram (Bq/kg) of plant matter (grass or leafy vegetables); - a few becquerels per litre (Bq/L) in rainwater or milk. Caesium 137 (together with an equivalent level of caesium 134) was also detected, generally at concentrations ten times lower than those observed for iodine 131. Tellurium 132 was occasionally detected in the air in late March. The various observations revealed that all French regions were affected to the same extent, albeit with some geographic and chronological fluctuations due to the movements of air masses. These levels are consistent with the forecasts based on modelling by IRSN in association with the French meteorological institute, Meteo-France. These concentrations were between 500 and more than 1, 000 times lower than those measured in France in early May 1986, following the Chernobyl accident. The maximum potential exposures (thyroid equivalent dose in one year

  3. Simultaneous Faraday filtering of the Mollow triplet sidebands with the Cs-D1 clock transition.

    Science.gov (United States)

    Portalupi, Simone Luca; Widmann, Matthias; Nawrath, Cornelius; Jetter, Michael; Michler, Peter; Wrachtrup, Jörg; Gerhardt, Ilja

    2016-11-25

    Hybrid quantum systems integrating semiconductor quantum dots (QDs) and atomic vapours become important building blocks for scalable quantum networks due to the complementary strengths of individual parts. QDs provide on-demand single-photon emission with near-unity indistinguishability comprising unprecedented brightness-while atomic vapour systems provide ultra-precise frequency standards and promise long coherence times for the storage of qubits. Spectral filtering is one of the key components for the successful link between QD photons and atoms. Here we present a tailored Faraday anomalous dispersion optical filter based on the caesium-D1 transition for interfacing it with a resonantly pumped QD. The presented Faraday filter enables a narrow-bandwidth (Δω=2π × 1 GHz) simultaneous filtering of both Mollow triplet sidebands. This result opens the way to use QDs as sources of single as well as cascaded photons in photonic quantum networks aligned to the primary frequency standard of the caesium clock transition.

  4. Radiotherapy of calcaneal spur; Strahlentherapeutische Behandlung des schmerzhaften Fersenbeinsporns

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, U. [Muenster Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Micke, O. [Muenster Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Glashoerster, M. [Muenster Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Ruebe, C. [Muenster Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Prott, F.J. [Muenster Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Willich, N. [Muenster Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie

    1995-04-01

    From April 1981 through December 1991, 18 patients with painful heel were irradiated mostly with the caesium or telecobalt unit, usually with a dose of 4 times 0.5 Gy. Among these patients, 12 could be followed up during a prolonged period on the basis of questionnaires. According to the categories of v. Pannewitz 17% of the patients were pain-free by the end of the treatment course, 22% showed marked improvement, 33% showed improvement and in 28% the pain was not influenced. Over an average of 41.5 months 58% of the patients reported freedom from pain. (orig./MG) [Deutsch] Von April 1981 bis Dezember 1991 wurden 18 Patienten mit einem schmerzhaften Fersenbeinsporn am Caesium- oder Telekobaltbestrahlungsgeraet behandelt, in der Regel mit einer Einstrahldosis von viermal 0,5 Gy. Von diesen Patienten konnten zwoelf mit Hilfe von Frageboegen ueber einen laengeren Zeitraum nachbeobachtet werden. Entsprechend der Einteilung nach von Pannewitz waren 17% der Patienten sofort nach der Behandlung schmerzfrei, 22% wesentlich gebessert, 33% gebessert und 28% unbeeinflusst. Nach im Median 41,5 Monaten berichteten 58% der Patienten von Schmerzfreiheit. (orig./MG)

  5. The use of {sup 210}Pb and {sup 137}Cs in environmental studies

    Energy Technology Data Exchange (ETDEWEB)

    Heijnis, H. [Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia). Environmental Radiochemistry Group, Environment Division

    1999-11-01

    The use of natural radioactivity in environmental studies has proven a very powerful tool to determine the dynamics of both natural and antrophogenic processes in our environment. The use of {sup 14}C in archaeology and past climate studies has led to many scientific discoveries (the shroud of Turin and Utze {sup t}he ice-man from Austria are two examples). The use of the {sup 238}U-decay series is of at least equal value to studies in archaeology and of past climates. Some of the Isotopes studied supplement {sup 14}C (which is limited to 40,000 years) data and allow dating of samples formed up to 500,000 years ago (see McCullough, this book of abstracts, pages 19-23), others can be utilised to date very young sediments, which can`t be dated by {sup 14}C.The so-called {sup 210}Pb dating method has been used over the past 3 decades to date recent sediment. The method uses the disequilibrium in the {sup 238}U decay chain, caused by the escape of the intermediate daughter {sup 222}Rn, a noble gas, from the earth`s crust. In the atmosphere the {sup 222}Rn decays via short-lived daughter isotopes to {sup 210}Pb. This {sup 210}Pb with a very convenient half-life of 22,3 years decays to stable {sup 206}Pb. By measuring the surface activity of a sediment core and subsequent samples at regular intervals, a chronology for the sediment core can be established (relative to the surface). In addition to {sup 210}Pb dating one could analyse the samples for {sup l37}Cs to establish an independent chronology based on a pulse of radioactive Caesium. The pulse of {sup 137}Cs originates from the atmospheric atomic-bomb test of the early sixties. The maximum of Caesium activity found in a core should correspond to the height of the tests (approximately 1963 in the Northern hemisphere). A combination of the two dating methods often leads to more reliable results in the chronology. Another use of {sup 137}Cs is to test if the sediment has been subject to bio-turbation or other mixing. In

  6. Dry deposition of gaseous radioiodine and particulate radiocaesium onto leafy vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Tschiersch, Jochen, E-mail: tschiersch@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg (Germany); Shinonaga, Taeko [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg (Germany); Heuberger, Heidi [TU Muenchen, Center of Life and Food Sciences Weihenstephan, Duernast 2, 85350 Freising (Germany)

    2009-10-15

    Radionuclides released to the atmosphere during dry weather (e.g. after a nuclear accident) may contaminate vegetable foods and cause exposure to humans via the food chain. To obtain experimental data for an appropriate assessment of this exposure path, dry deposition of radionuclides to leafy vegetables was studied under homogeneous and controlled greenhouse conditions. Gaseous {sup 131}I-tracer in predominant elemental form and particulate {sup 134}Cs-tracer at about 1 {mu}m diameter were used to identify susceptible vegetable species with regard to contamination by these radionuclides. The persistence was examined by washing the harvested product with water. The vegetables tested were spinach (Spinacia oleracea), butterhead lettuce (Lactuca sativa var. capitata), endive (Cichorium endivia), leaf lettuce (Lactuca sativa var. crispa), curly kale (Brassica oleracea convar. acephala) and white cabbage (Brassica oleracea convar. capitata). The variation of radionuclides deposited onto each vegetable was evaluated statistically using the non-parametric Kruskal-Wallis Test and the U-test of Mann-Whitney. Significant differences in deposited {sup 131}I and {sup 134}Cs activity concentration were found among the vegetable species. For {sup 131}I, the deposition velocity to spinach normalized to the biomass of the vegetation was 0.5-0.9 cm{sup 3} g{sup -1} s{sup -1} which was the highest among all species. The particulate {sup 134}Cs deposition velocity of 0.09 cm{sup 3} g{sup -1} s{sup -1} was the highest for curly kale, which has rough and structured leaves. The lowest deposition velocity was onto white cabbage: 0.02 cm{sup 3} g{sup -1} s{sup -1} (iodine) and 0.003 cm{sup 3} g{sup -1} s{sup -1} (caesium). For all species, the gaseous iodine deposition was significantly higher compared to the particulate caesium deposition. The deposition depends on the sensitive parameters leaf area, stomatal aperture, and plant morphology. Decontamination by washing with water was very

  7. Study of the characteristics of neutron monitor area applied to the evaluation of dose rates in a 15 MeV radiotherapy accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Candido M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Fisica]. E-mail: candido_1998@yahoo.com; Patrao, Karla C.S.; Pereira, Walsan W.; Fonseca, Evaldo S.; Giannoni, Ricardo A. [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Neutrons]. E-mails: karla@ird.gov.br; walsan@ird.gov.br; Batista, Delano V.S. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil). Setor de Fisica Medica]. E-mail: delano@inca.gov.br

    2007-07-01

    Currently, in Radiotherapy, the use of linear accelerators is becoming each time more common. From Radiation Protection point of view, these instruments represent an advance in relation to the cobalt and caesium irradiators, mainly due to absence of the radioactive material. On the other hand, accelerators with the energies superior to 10 MeV produce contamination of the therapeutic beam with the presence of neutrons generated in the interaction of high-energy photons with high atomic number materials from the own irradiator. The present work carries through measurements in a linear accelerator of 15 MeV using three neutron area monitors for a comparison of the response of these instruments, evaluating its adequacy to this measurement. Characteristics of use and operation associates to parameters such as: monitor dead time, monitor gamma rejection, and calibration results are also analyzed in this study. (author)

  8. Registration of ELF waves in rocket-satellite experiment with plasma injection

    Science.gov (United States)

    Korobeinikov, V. G.; Oraevskii, V. N.; Ruzhin, Iu. Ia.; Sobolev, Ia. P.; Skomarovskii, V. S.; Chmyrev, V. M.; Namazov, C. A.; Pokhunkov, A. A.; Nesmeianov, V. I.

    1992-12-01

    Two rocket KOMBI-SAMA experiments with plasma injection at height 100-240 km were performed in August 1987 in the region of Brazilian magnetic anomaly (L = 1.25). The launching time of the rocket was determined so that plasma injection was at the time when COSMOS 1809 satellite passed as close as possible to magnetic tube of injection. Caesium plasma jet was produced during not less than 300 s by an electric plasma generator separated from the payload. When the satellite passed the geomagnetic tube intersecting the injection region an enhancement of ELF emission at 140 Hz, 450 Hz by a factor of 2 was registered on board the satellite. An enhancement of energetic particle flux by a factor of 4-5 was registered on board the rocket. Observed ELF emission below 100 Hz is interpreted as the generation of oblique electromagnetic ion-cyclotron waves due to drift plasma instability at the front of the plasma jet.

  9. Fields of View for Environmental Radioactivity

    CERN Document Server

    Malins, Alex; Machida, Masahiko; Takemiya, Hiroshi; Saito, Kimiaki

    2015-01-01

    The gamma component of air radiation dose rates is a function of the amount and spread of radioactive nuclides in the environment. These radionuclides can be natural or anthropogenic in origin. The field of view describes the area of radionuclides on, or below, the ground that is responsible for determining the air dose rate, and hence correspondingly the external radiation exposure. This work describes Monte Carlo radiation transport calculations for the field of view under a variety of situations. Presented first are results for natural 40K and thorium and uranium series radionuclides distributed homogeneously within the ground. Results are then described for atmospheric radioactive caesium fallout, such as from the Fukushima Daiichi Nuclear Power Plant accident. Various stages of fallout evolution are considered through the depth distribution of 134Cs and 137Cs in soil. The fields of view for the natural radionuclides and radiocaesium are different. This can affect the responses of radiation monitors to th...

  10. Distribution of /sup 137/Cs in surface intertidal sediments from the Solway Firth

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D.G.; Miller, J.M.; Roberts, P.D. (Institute of Geological Sciences, Keyworth (UK))

    1984-05-01

    The distribution of /sup 137/Cs from the Sellafield (Windscale) nuclear fuel reprocessing plant has been examined in detail in the surface intertidal sediments of the inner Solway Firth by means of a hovercraft-borne radiometric survey. With the exception of a belt of relatively active sands to the south of Silloth, caesium distribution is generally consistent with that of fine-grained sediment such that the highest concentrations occur in mud flat and salt marsh sediments which are most extensive in sheltered coastal embayments. /sup 137/Cs activities in July 1980 were typically 2 to 30 pCi g/sup -1/ but locally exceeded 50 pCi g/sup -1/. These levels are considerably lower than those recorded in locations, such as the outer Solway and Ravenglass estuary, which are closer to the Sellafield outfall.

  11. Radioactivity monitoring of the Irish marine environment 1998 and 1999

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, T.; Long, S.; Dowdall, A. [and others

    2000-09-01

    The safety of the food chain and the protection of the environment are prime concerns of the Irish public. This report presents the results of the marine radioactivity monitoring programme carried out by the Radiological Protection Institute of Ireland (RPII) during 1998 and 1999. The primary objective of the programme is to assess the exposure of the Irish population resulting from radioactive contamination of the Irish marine environment and to estimate the risks to health from this exposure. Discharged radioactive waste from the British Nuclear Fuels plc (BNFL) reprocessing plant at Sellafield continues to be the dominant source of this contamination. In particular, the remobilization from sediments of historic discharges makes an important contribution to the levels of radioactivity in the seawater of the western Irish Sea. Approximately 300 samples of fish, shellfish, seaweed, seawater and sediment were collected in 1998 and again in 1999. Both the Marine Institute and the Department of the Marine and Natural Resources assisted the Institute with this sampling. The samples were analysed for a range of contaminating radionuclides at the Institute's radio-analytical laboratory. The results show that the radionuclide of greatest dosimetric significance continues to be caesium-137. The activity concentration of this radionuclide in the Irish marine environment has remained relatively stable since the mid 1990s but at a lower level than that observed during the previous two decades. Along the Irish coastline the highest activity concentrations observed are in the north-east. Since 1994 the commissioning and operation of new facilities at Sellafield have resulted in an increase in the discharges of technetium-99 to the Irish Sea. This has been reflected in an increase in the activity concentrations of this radionuclide at all east coast sampling sites between 1994 and 1999. However, the low radiotoxicity of technetium-99 means that it is generally of lesser

  12. Nuclear disaster. Fukushima, hundred years of decontamination; Catastrophe nucleaire: Fukushima, cent ans de decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Dupin, L.

    2011-04-15

    This article gives an overview of what will have to be done on the site of Fukushima to decontaminate and to dismantle it. Based on the experience gained in Three Mile Island and in Chernobyl, experts foresee ten years of work within the reactor cores, thirty years around the plant, sixty years of decontamination within the no man's land area around the plant; and centuries as far as scattered spots are concerned more than hundred kilometres away from the plant. Three radionuclides must be surveyed, but with different half lives: iodine 131 (8 days), caesium 137 (30 years), and plutonium 239 (24000 years). The expertise of French companies (Areva, Assystem, Bouygues and Vinci) in reactor dismantling, dismantling procedure design, and public works (protection arch like in Chernobyl) is briefly evoked, as well as the French approach for post-accident management

  13. The lesson of the Chernobyl disaster

    Energy Technology Data Exchange (ETDEWEB)

    Milhaud, G. (Hopital Saint-Antoine, 75 Paris (FR))

    1991-01-01

    On april 26, 1986 a major nuclear disaster took place at 1 h 24 min local time, destroying the fourth reactor of the Chernobyl plant. Five years later the consequences of the disaster are still not fully known. Nevertheless the long term future of nuclear energy in the world is uncertain. Questions need to be answered by observing hard facts if emotional attitudes are not to prevail over reality. The reactor and its core were destroyed by an explosion, causing two radioactive jet emissions of iodine 131, followed by caesium 137. Both elements are mainly incorporated in the body via food. The Chernobyl disaster was a consequence of inadequate safety regulations and human error. Enforcement of strict regulations are likely to be highly effective in preventing a further catastrophe. However, governments should consider another possibility. What would be the consequences for public health if a terroristic act deliberately destroyed a nuclear power station.

  14. The legacy of Chernobyl

    Energy Technology Data Exchange (ETDEWEB)

    Bojcun, M.

    1991-04-20

    This article looks at daily life in the Northern Ukraine, where the fallout effects from the Chernobyl nuclear reactor accident were felt most keenly. High levels of radioactive iodine 131, strontium 90 and caesium 137 are still present five years on and the health of the population, including those evacuated from the exclusion zones, is at risk from leukaemia and thyroid problems, especially among children. Other worrying reports suggest the occurence of a new disease, ''Chernobyl AIDs'', in which sufferers' immune systems are depressed. Other major outstanding problems include the integrity of the concrete sarcophagus enclosing the damaged reactor, and the continued consumption of locally grown contaminated food due to government inadequacies in supplying ''clean'' equivalents. (UK).

  15. Ultrahigh and persistent optical depths of cesium in Kagomé-type hollow-core photonic crystal fibers

    Science.gov (United States)

    Kaczmarek, Krzysztof T.; Saunders, Dylan J.; Sprague, Michael R.; Kolthammer, W. Steven; Feizpour, Amir; Ledingham, Patrick M.; Brecht, Benjamin; Poem, Eilon; Walmsley, Ian A.; Nunn, Joshua

    2015-12-01

    Alkali-filled hollow-core fibres are a promising medium for investigating light-matter interactions, especially at the single-photon level, due to the tight confinement of light and high optical depths achievable by light-induced atomic desorption. However, until now these large optical depths could only be generated for seconds at most once per day, severely limiting the practicality of the technology. Here we report the generation of highest observed transient ($>10^5$ for up to a minute) and highest observed persistent ($>2000$ for hours) optical depths of alkali vapours in a light-guiding geometry to date, using a caesium-filled Kagom\\'e-type hollow-core photonic crystal fibre. Our results pave the way to light-matter interaction experiments in confined geometries requiring long operation times and large atomic number densities, such as generation of single-photon-level nonlinearities and development of single photon quantum memories.

  16. Investigation into thallium sites and defects in doped scintillation crystals

    Energy Technology Data Exchange (ETDEWEB)

    Blacklocks, A.N.; Chadwick, A.V. [Functional Materials Group, School of Physical Sciences, University of Kent (United Kingdom); Jackson, R.A. [Lennard-Jones Laboratories, School of Physical and Geographical Sciences, Keele University (United Kingdom); Hutton, K.B. [Hilger Crystals, Westwood, Margate, Kent (United Kingdom)

    2007-03-15

    Thallium doped caesium iodide, CsI(Tl), and sodium iodide, NaI(Tl) are two of the most efficient scintillators developed and are already widely used for radiation detection and imaging applications. Their use in fast imaging applications however has been hindered by a long lasting high level of afterglow - the percentage of the luminescence pulse remaining a short time after excitation. Very little is known about the point defects in these crystals, such as structure and concentrations, and the first step to understanding the causes of the afterglow is to understand the nature of the defects responsible for the scintillation. In this paper the local structure of the thallium activator ion has been investigated via EXAFS spectroscopy and some basic intrinsic defects calculated using the General Utility Lattice Program (GULP). (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Frequency tuning of single photons from a whispering-gallery mode resonator to MHz-wide transitions

    DEFF Research Database (Denmark)

    Schunk, G.; Vogl, U.; Sedlmeir, F.

    2016-01-01

    Quantum repeaters rely on interfacing flying qubits with quantum memories. The most common implementations include a narrowband single photon matched in bandwidth and central frequency to an atomic system. Previously, we demonstrated the compatibility of our versatile source of heralded single...... photons, which is based on parametric down-conversion in a triply resonant whispering-gallery mode resonator, with alkaline transitions [Schunk et al., Optica 2015, 2, 773]. In this paper, we analyse our source in terms of phase matching, available wavelength-tuning mechanisms and applications...... to narrowband atomic systems. We resonantly address the D1 transitions of caesium and rubidium with this optical parametric oscillator pumped above its oscillation threshold. Below threshold, the efficient coupling of single photons to atomic transitions heralded by single telecom-band photons is demonstrated...

  18. Cea and CISBIO-international create the -GIP sources HA- and revise their strategy for the management of disused sealed sources; Le CEA et CISBIO-international creent le GIP sources HA, et revisent leur strategie de gestion des sources scellees usagees

    Energy Technology Data Exchange (ETDEWEB)

    Sevestre, B.; Crabol, B.; Lamberton, I. [GIP sources HA, 91 - Gif-sur-Yvette (France)

    2010-10-15

    According to French regulation, CEA and CISBIO, who have distributed many sealed sources in the past, have to recover all the disused sources. During 2009, CEA and CISBIO created the 'groupement d'interet public (GIP) sources HA', with the objective of recovering and managing high-activity sealed sources (HASS), mainly cobalt-60 and caesium-137, distributed in France. CEA and CISBIO can also recover and repatriate similar sources or any other types of sealed sources distributed by them in foreign countries, when the user has no national solution, or when international organisations, such as the IAEA, identify a security issue. With the objective of optimising this mission, GIP, CEA and CISBIO are ready to cooperate with the present source suppliers who may need the use of hot cells in France, may contribute to some repatriation operations, or may recycle some batches of recovered sealed sources not yet conditioned as waste packages. (authors)

  19. Search for persons

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, H. [Asklepios Klinik St. Georg, Radiology, Lohmuehlenstr. 5 20099 Hamburg (Germany)], E-mail: Hermann.vogel@ak-stgeorg.lbk-hh.de

    2007-08-15

    X-rays and gamma-rays are used to detect hidden persons in vehicles, containers, and railway wagons. They are produced with accelerators, X-ray tubes, cobalt 60 and caesium 137. Fan beams adjusted to a line of digital detectors produce the image. The resolution is sufficient to recognise a human being. The recognition of persons with transmission images is limited by superimposition; backscatter imaging produces clearer images but of one single layer only. The future will bring new applications of search for persons with X-rays. Crimes and terrorist attacks will induce added demand for security, where search with X-rays and gamma-rays will keep its important role or even increase it.

  20. Synthesis and crystallographic study of the compounds in the system Cs{sub 2}O - Al{sub 2}O{sub 3} - SiO{sub 2}; Synthese et etude cristallographique des composes du systeme Cs{sub 2}O - Al{sub 2}O{sub 3} - SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Langlet, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-05-01

    A study has been made on the preparation, structure and thermal evolution of some definite compounds in the system: Cs{sub 2}O - Al{sub 2}O{sub 3} - SiO{sub 2}. Precise details are given about the structure of the following compounds: CsAlO{sub 2}, RbAlO{sub 2}, KAlO{sub 2} and NaAlO{sub 2}; CsAlO{sub 2}, 2 H{sub 2}O; Cs{sub 2}O, 11 Al{sub 2}O{sub 3}; Cs{sub 2}O, 2 SiO{sub 2}; Cs{sub 2}O, 4 SiO{sub 2} and Rb{sub 2}O, 4 SiO{sub 2}; CsAlSiO{sub 4}; CsAlSi{sub 2}O{sub 6}; Cs{sub 4}Ge{sub 11}O{sub 24} and Rb{sub 4}Ge{sub 11}O{sub 24}. The long term purpose of this work was to find a compound which would be insoluble, refractory and at the same time able to contain radioactive isotopes of cesium and thus suitable as radiation sources. The knowledge of the properties and structure of aluminates, silicates and aluminosilicates is a necessary stage before the elaboration of ceramic caesium sources. The compound which seems quite convenient for this use, Cs{sub 2}AlSi{sub 2}O{sub 6}, is closely related to the natural mineral 'pollucite', and offers interesting properties. (author) [French] Ce travail constitue une etude de la preparation, de la structure et de l'evolution thermique des composes definis du systeme: Cs{sub 2}O - Al{sub 2}O{sub 3} - SiO{sub 2} et de quelques homologues. Des precisions sont donnees sur la structure des composes suivants: CsAlO{sub 2}, RbAlO{sub 2}, KAlO{sub 2} et NaAlO{sub 2}; CsAlO{sub 2}, 2 H{sub 2}O; Cs{sub 2}O, 11 Al{sub 2}O{sub 3}; Cs{sub 2}O, 2 SiO{sub 2}; Cs{sub 2}O, 4 SiO{sub 2} et Rb{sub 2}O, 4 SiO{sub 2}; CsAlSiO{sub 4}; CsAlSi{sub 2}O{sub 6}; Cs{sub 4}Ge{sub 11}O{sub 24} et Rb{sub 4}Ge{sub 11}O{sub 24}. Le but a long terme de cette etude consistait a obtenir un compose a la fois refractaire et insoluble, susceptible de contenir un isotope radioactif du caesium, et d'etre utilise comme source de rayonnement. La connaissance des proprietes et de la structure des aluminates, silicates et aluminosilicates represente

  1. Physiological and ecological factors influencing the radiocaesium contamination of fish species from Kiev reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Koulikov, A.O. [A.N. Severtzov Institute of Evolutionary Morphology and Ecology of Animals, Russian Academy of Sciences, Moscow (Russian Federation)

    1995-11-23

    The monitoring of {sup 137}Cs contamination of fish from the northern part of the Kiev reservoir between 1987 and 1992 indicated systematic differences in the long-term average contamination levels of different species, which are closely related to their trophic levels. The average contamination of the predatory species: perch (Perca fluviatilis) and pike (Esox lucius) were roughly factors of 6.3 and 4.4 respectively, higher than those of the nonpredatory species: bream (Abramis brama), silver bream (Blicca bjoerkna) and rudd (Scardinius erythrophothalmus). For tench (Tinca tinca) and goldfish (Carassius sp.), this factor is 2. The solution of the caesium balance equation in fish obtained for equilibrium conditions, which is applicable to the long-term contamination, provides some explanations for these accumulation differences between the species with respect to influences by different ecological and physiological factors.

  2. Using optical nanofibers for spectroscopy

    CERN Document Server

    Garcia-Fernandez, R; Bruse, F; Dan, C; Karapetyan, K; Rehband, O; Stiebeiner, A; Wiedemann, U; Meschede, D; Rauschenbeutel, A

    2011-01-01

    We review our recent progress in the production and characterization of tapered optical fibers with a sub-wavelength diameter waist. Such fibers exhibit a pronounced evanescent field and are therefore a useful tool for highly sensitive evanescent wave spectroscopy of adsorbates on the fiber waist or of the medium surrounding. We use a carefully designed flame pulling process that allows us to realize preset fiber diameter profiles. In order to determine the waist diameter and to verify the fiber profile, we employ scanning electron microscope measurements and a novel accurate in situ optical method based on harmonic generation. We use our fibers for linear and non-linear absorption and fluorescence spectroscopy of surface-adsorbed organic molecules and investigate their agglomeration dynamics. Furthermore, we apply our spectroscopic method to quantum dots on the surface of the fiber waist and to caesium vapor surrounding the fiber. Finally, towards dispersive measurements, we present our first results on buil...

  3. First results of the ITER-relevant negative ion beam test facility ELISE (invited).

    Science.gov (United States)

    Fantz, U; Franzen, P; Heinemann, B; Wünderlich, D

    2014-02-01

    An important step in the European R&D roadmap towards the neutral beam heating systems of ITER is the new test facility ELISE (Extraction from a Large Ion Source Experiment) for large-scale extraction from a half-size ITER RF source. The test facility was constructed in the last years at Max-Planck-Institut für Plasmaphysik Garching and is now operational. ELISE is gaining early experience of the performance and operation of large RF-driven negative hydrogen ion sources with plasma illumination of a source area of 1 × 0.9 m(2) and an extraction area of 0.1 m(2) using 640 apertures. First results in volume operation, i.e., without caesium seeding, are presented.

  4. Commitment of involved actors in the preparation of accidental and post-accident situations: European experiments; Engagement des parties prenantes a la preparation aux situations accidentelles et post-accidentelles: experiences Europeennes

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Th. [CEPN, 28 rue de la Redoute, 92260 Fontenay-aux-Roses (France)

    2010-07-01

    The author briefly describes some approaches developed within the EURANOS European research programme between 2004 and 2009 which aims at promoting the building up of a European network (NERIS) for the management of nuclear accidental and post-accident situations. Notably, he comments the experiment which took place in the Montbeliard district where two types of radiological events have been modelled and simulated: an accident in the Fessenheim nuclear power plant with two scenarios of release, and a transportation accident with a release of radioactive caesium 137. He also evokes the Norwegian experience and some other actions in Finland, Great-Britain, Spain and Slovakia where reflections on the management of accidental and post-accident situations or crisis exercises have been organized

  5. Impact on the marine environment of radioactive releases resulting from the Fukushima-Daiichi nuclear accident. May 13, 2011; Impact sur le milieu marin des rejets radioactifs consecutifs a l'accident nucleaire de Fukushima Dai-ichi. 13 mai 2011

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This information note updates and supplements the previous note of 4 April on the same subject. It describes the origins of the contamination of the marine environment (Direct releases into the sea close to the damaged reactors, atmospheric fall-out onto the surface of the sea, transport of radioactive pollution by leaching of contaminated soil). Then, while proposing several maps, the authors analyse and comment the dispersion in the sea of radioactive pollutants: ocean currents off the Japanese coasts, charts showing the distribution of caesium 137 in seawater, and results of simulations of dispersion. The report briefly discusses the impact of radioactive pollution on living species: concentrations observed in fish, expected concentrations based on the seawater measurements. Finally, it briefly discusses the presence of radionuclides in sediments

  6. Reference: 528 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 528 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u17270011i An Rui et al. 2007 Fe...m (K+) and caesium (Cs+). AtNHX8 overexpression in a triple-deletion yeast mutant AXT3 that exhibits defecti...ve Na+/Li+ transport specifically suppresses sensitivity to Li+, but does not affect Na+ sensitivity. Likewi...n antiporter-1 family in Arabidopsis thaliana, encodes a putative Li/H antiporter. 4 718-28 17270011 2007 Fe...b The Plant journal An Rui|Chai Mao-Feng|Chen Jia|Chen Qi-Jun|Lu Ping-Li|Qin Zhi-Xiang|Su Zhao|Wang Xue-Chen

  7. Borromean three-body FRET in frozen Rydberg gases

    Science.gov (United States)

    Faoro, R.; Pelle, B.; Zuliani, A.; Cheinet, P.; Arimondo, E.; Pillet, P.

    2015-09-01

    Controlling the interactions between ultracold atoms is crucial for quantum simulation and computation purposes. Highly excited Rydberg atoms are considered in this prospect for their strong and controllable interactions known in the dipole-dipole case to induce non-radiative energy transfers between atom pairs, similarly to fluorescence resonance energy transfer (FRET) in biological systems. Here we predict few-body FRET processes in Rydberg atoms and observe the first three-body resonance energy transfer in cold Rydberg atoms using cold caesium atoms. In these resonances, additional relay atoms carry away an energy excess preventing the two-body resonance, leading thus to a Borromean type of energy transfer. These few-body processes present strong similarities with multistep FRET between chromophores sometimes called donor-bridge-acceptor or superexchange. Most importantly, they generalize to any Rydberg atom and could lead to new implementations of few-body quantum gates or entanglement.

  8. Collective dose to the European Community from nuclear industry effluents discharge in 1978

    CERN Document Server

    Camplin, W C

    1983-01-01

    The results are presented of a study to evaluate the collective dose commitment to the population of the European Community from effluents released by the nuclear industry within the EC in 1978. Airborne and liquid effluent discharge data have been taken from published sources, and computer modelling techniques have been used to predict the transfer of radioactivity through the environment to man. The collective dose commitments due to discharges from each nuclear installation have been evaluated and the comparative significance of individual radionuclides and their pathways to man have been considered. Airborne releases resulted in an estimated collective effective dose equivalent commitment of 95 man Sv, the major part of which is due to carbon-14 from both power stations and reprocessing plants. The collective effective dose equivalent commitment from liquid effluents is estimated to be 408 man Sv, mostly due to caesium-137 and other radionuclides from the Sellafield (formerly Windscale) reprocessing plant...

  9. Is OPERA Neutrino Superluminal Propagation similar to Gain-Assisted Superluminal Light Propagation

    CERN Document Server

    Pankovic, Vladan

    2011-01-01

    In this work we consider a possible conceptual similarity between recent, amazing OPERA experiment of the superluminal propagation of neutrino and experiment of the gain-assisted superluminal light propagation realized about ten years ago. Last experiment refers on the propagation of the light, precisely laser pulse through a medium, precisely caesium atomic gas, with characteristic anomalous dispersion and corresponding negative group-velocity index that implies superluminal propagation of the light through this medium. Nevertheless all this, at it has been pointed out by authors, "is not at odds with causality or special relativity", since it simply represents "a direct consequence of the classical interference between ... different frequency components". We observe that OPERA experiment is in many aspects conceptually very similar to the gain-assisted superluminal light propagation, including superposition of the neutrinos component and superluminality magnitudes. For this reason we suppose that OPERA expe...

  10. ACCUMULATION OF 134CS IN THE PEPPER DEPENDING ON SOIL CHARACTERISTICS AND METHODS FOR REDUCTION OF THE TRANSFER OF RADIONUCLIDES FROM THE SOIL INTO THE VEGETATION PRODUCTION

    Directory of Open Access Journals (Sweden)

    D STANEVA

    2007-04-01

    Full Text Available The particularities of the soil as sorbent, its complex composition and the differences in its properties impose the research of the accumulation of the The development of methods for reduction of the transfer of radionuclides from the soil into the vegetation production being of particular signifi cance for the implementation agricultural activities in conditions of radioactive pollution of the soil, the impact of potassium, calcium and EDTA or ethylenediaminetetraac etic acid over the accumulation of radio-caesium from the soil into the plants. As it is seen from the results presented, the input of potassium, calcium and EDTA in the Orthic Luvisols signifi cantly decreased the input of Сs-134 into the pepper plants.

  11. 2,2,6,6-Tetrakis(biphenyl-2-yl-4,4,8,8-tetramethylcyclotetrasiloxane

    Directory of Open Access Journals (Sweden)

    Erik P. A. Couzijn

    2009-09-01

    Full Text Available The title compound, [–Si(C12H92OSi(CH32O–]2, was obtained unintentionally as the product of an attempted crystallization of caesium bis(biphenyl-2,2′-diylfluorosilicate from dimethylformamide. In the crystal, the molecule is located on an inversion center and the siloxane ring adopts a twist-chair conformation with the two dimethyl-substituted Si atoms lying 0.7081 (5 Å out of the plane defined by the two bis(biphenyl-2-yl-substituted Si atoms and the four O atoms. In each Si(C12H92 unit, the orientation of one terminal phenyl ring relative to the phenylene ring of the other biphenyl moiety suggests a parallel displaced π–π stacking interaction [centroid distance = 4.2377 (11 Å and dihedral angle = 15.40 (9°].

  12. Experimental study on the activation process of GaAs spin—polarized electron source

    Institute of Scientific and Technical Information of China (English)

    RuanCun-Jun

    2003-01-01

    GaAs spin-polarized electron source is a new kind of electron source, where the GaAs semiconductor crystal is used as a photocathode under the irradiation of helicity light. In this paper the activation process of the GaAs spin-polarized electron source is unvestigated experimentally in detail, during which the negative electron affinity of the photo cathode should be achieved more carefully by absorbing the caesium and oxygen on the surface of the GaAs crystal under ultrahigh vacuum conditions. Besides the different activation processes, the important physical parameters are studied to achieve the optimum activation results. At the same time the stability and lifetime of the polarized electron beam are explored for future experiments. Some important experimental data have been acquired.

  13. Crystal structure of [UO2(NH35]NO3·NH3

    Directory of Open Access Journals (Sweden)

    Patrick Woidy

    2016-12-01

    Full Text Available Pentaammine dioxide uranium(V nitrate ammonia (1/1, [UO2(NH35]NO3·NH3, was obtained in the form of yellow crystals from the reaction of caesium uranyl nitrate, Cs[UO2(NO33], and uranium tetrafluoride, UF4, in dry liquid ammonia. The [UO2]+ cation is coordinated by five ammine ligands. The resulting [UO2(NH35] coordination polyhedron is best described as a pentagonal bipyramid with the O atoms forming the apices. In the crystal, numerous N—H...N and N—H...O hydrogen bonds are present between the cation, anion and solvent molecules, leading to a three-dimensional network.

  14. ALICE-HMPID performance in the identification of deuterons in central Pb-Pb collisions in the transverse momentum range 3-8 GeV/c.

    CERN Document Server

    Vella, Julia

    2016-01-01

    The summer student project carried out from June to August of 2016 will be covered in this report. The main aim of this programme was to monitor the performance of the detector, such that two macros were written to carry out this objective. The resolution of the measurement of the angle (among other parameters) depends on the number of photons per ring, and therefore we needed to monitor the number of photons. This quantity depends on the gain of the Multi Wire Proportional Chamber (MWPC) and the radiator transparency and the Caesium Iodide Quantum Efficiency cannot. However, the Quantum Efficiency cannot be measured directly unlike the gain and transparency, and may therefore only be inferred from the stability of the number of photons (assuming that the other parameters are also stable). Therefore a macro was implemented to extract these values, and summary plots were used for comparative analysis.

  15. Experimental study on the activation process of GaAs spin-polarized electron source

    Institute of Scientific and Technical Information of China (English)

    阮存军

    2003-01-01

    GaAs spin-polarized electron source is a new kind of electron source, where the GaAs semiconductor crystal is used as a photocathode under the irradiation of helicity light. In this paper the activation process of the GaAs spin-polarized electron source is investigated experimentally in detail, during which the negative electron affinity of the photo cathode should be achieved more carefully by absorbing the caesium and oxygen on the surface of the GaAs crystal under ultrahigh vacuum conditions. Besides the different activation processes, the important physical parameters are studied to achieve the optimum activation results. At the same time the stability and lifetime of the polarized electron beam are explored for future experiments. Some important experimental data have been acquired.

  16. Cs10Ta29.27O78

    Directory of Open Access Journals (Sweden)

    Wolfgang Schnick

    2009-02-01

    Full Text Available Single crystals of caesium tantalate(V, Cs10Ta29.27O78, were obtained as a serendipitous product in a welded tantalum ampoule by a blank reaction of CsBr and bismuth subnitrate [Bi5O(OH9(NO34] with the container material. The crystal structure of the title compound is made up of a three-dimensional framework constituted by two types of layers, viz. (Ta6O15n and (Ta3O9n, parallel to (001, which are linked together by TaO6 octahedra (3m. symmetry along [001]. This framework has cavities where three independent Cs+ ions (3m. and overline{6}m2 symmetry, respectively are located. The compound reveals a Ta deficiency at one trigonal prismatic coordinated site (overline{6}m2 symmetry. The composition of the title compound was verified by energy-dispersive X-ray analysis of single crystals.

  17. Foodstuffs And Cancer: Analysis Of Radionuclides And Its Radiation Levels In Common Ghanaian Maize.

    Directory of Open Access Journals (Sweden)

    George Felix Acquah

    2013-09-01

    Full Text Available By gamma spectroscopic measurement, content of natural and anthropogenic radionuclides and their activity levels were determined in selected common Ghanaian maize. The purpose was to establish whether these levels and subsequently their annual effective doses from the intake of these radionuclides were within the internationally acceptable limits. Six different maize varieties were collected, processed and data on each sample analyzed using a High Purity Germanium Detector. The activity levels and annual effective doses were calculated for the samples. The most significant radionuclides obtained from the analysis were; Potassium (40K, Uranium (238U, Caesium (134Cs, and Thorium (232Th. The average annual effective doses obtained from this study were 0.0039 mSv and 0.0012 mSv for dried and ashed samples respectively. This study concluded that the radionuclide activities and the annual effective doses were within acceptable standard levels and hence these Ghanaian maize varieties suitable for human consumption.

  18. An Analysis of NTSC's Timekeeping Hydrogen Masers

    Science.gov (United States)

    Hui-jie, Song; Shao-wu, Dong; Zheng-ming, Wang; Li-li, Qu; Yue-juan, Jing; Wei, Li

    2016-10-01

    In this article, the hydrogen masers in the NTSC (National Time Service Center) timekeeping laboratory are tested. In order to avoid the impact of larger noise of caesium atomic clocks, TA(k) or UTC(k) is not used as reference, instead, the four hydrogen masers are mutually referred and tested. The frequency stability of hydrogen masers is analyzed using the four-cornered hat method, and the Allan standard deviations of each single hydrogen maser in different sample times are estimated. Then, according to the characteristics of hydrogen masers, by removing the trend term, excluding outliers, and smoothing the data with a mathematical method to separate the Gaussian noises of hydrogen masers, and finally by through the Kolmogorov-Smirnov test, the Gaussian noise of each hydrogen maser is estimated.

  19. In situ characterization of an optically thick atom-filled cavity

    Science.gov (United States)

    Munns, J. H. D.; Qiu, C.; Ledingham, P. M.; Walmsley, I. A.; Nunn, J.; Saunders, D. J.

    2016-01-01

    A means for precise experimental characterization of the dielectric susceptibility of an atomic gas inside an optical cavity is important for the design and operation of quantum light-matter interfaces, particularly in the context of quantum information processing. Here we present a numerically optimized theoretical model to predict the spectral response of an atom-filled cavity, accounting for both homogeneous and inhomogeneous broadening at high optical densities. We investigate the regime where the two broadening mechanisms are of similar magnitude, which makes the use of common approximations invalid. Our model agrees with an experimental implementation with warm caesium vapor in a ring cavity. From the cavity response, we are able to extract important experimental parameters, for instance the ground-state populations, total number density, and the magnitudes of both homogeneous and inhomogeneous broadening.

  20. Modelling of Radionuclides Transfer and Ambient Dose Rates in Fukushima Forest Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Calmon, P.; Gonze, M.A.; Mourlon, C.; Simon-Cornu, M. [Institute of Radiation Protection and Nuclear Safety, CE Cadarache-Bat 153, BP3 - 13115 St-Paul-lez- Durance cedex (France)

    2014-07-01

    The Fukushima nuclear accident led to high atmospheric depositions of volatile fission products such as Caesium, Iodine and Tellurium isotopes, in north-eastern Japan. The radioactive content and ambient radiation level are particularly high in forest ecosystems, partly due to the enhancement of airborne radionuclides capture by forest canopies. The contamination is likely to be dominated in the next decades by Cesium-137, due to its long physical half-life (i.e. 30 years) and its ability to be immobilized and/or recycled within the biotic and abiotic forest components. Thus the long-term management of contaminated forested areas is an environmental, economic and social challenge for Japanese authorities. IRSN developed a forest model ten years ago and implemented it in the ASTRAL software. This model has been tested against measurements in various Fukushima forest stands with varying deposition and meteorological conditions, typical forest ecosystems quite different from those in western Europe, and also with a hilly landscape. This is a great opportunity to test, improve and validate our model. We can take advantage of the expertise gained following the Chernobyl accident fallout, of the data derived from Japanese publications and of the possibility to conduct field measurements. At first, a German scenario in a Norway spruce stand, following the Chernobyl accident has been tested. All deposition and rainfall events were documented. The model could reproduce very closely the dynamics of caesium concentration in soil and input fluxes (e.g. direct vs indirect throughfall, litterfall). For this scenario, deposition occurred mostly with rainfall and 90% of the total deposit was recovered in the soil layer 1 year after the accident. On the opposite, another scenario at Tochigi Prefecture in a Japanese cedar stand, for the Fukushima accident is characterized by 40% of deposition on the soil 1 year after the accident. For this scenario, much uncertainty concerns both

  1. Measurements of Diffusion Resonances for the Atom Optics Quantum Kicked Rotor

    CERN Document Server

    Williams, M E K; Daley, A J; Gray, R N C; Tan, S M; Parkins, A S; Leonhardt, R; Christensen, N

    2002-01-01

    We present experimental observations of diffusion resonances for the quantum kicked rotor with weak decoherence. Cold caesium atoms are subject to a pulsed standing wave of near-resonant light, with spontaneous emission providing environmental coupling. The mean energy as a function of the pulse period is determined during the late-time diffusion period for a constant probability of spontaneous emission. Structure in the late-time energy is seen to increase with physical kicking strength. The observed structure is related to Shepelyansky's predictions of the initial quantum diffusion rates. Additional results of diffusion rates as a function of the effective Planck's constant are given, showing non-trivial behaviour in the quantum-to-classical transition regime.

  2. Speed of the CERN Neutrinos released on 22.9.2011 - Was stated superluminality due to neglecting General Relativity?

    CERN Document Server

    Kundt, Wolfgang

    2011-01-01

    During the years 2009 to 2011, neutrino beams were fired repeatedly from CERN towards a detector in Italy's Gran Sasso tunnel, some 4 deg south and 7 deg east of CERN, at a distance of 730.5 km, in the shape of short bunches of particles. Their time of flight (2.5 msec) was measured at high accuracy (nsec) with caesium clocks (Reich 2011). Remarkably, the CNGS team found a deficit of 61 nsec compared with propagation at the speed of light, and concluded at superluminal speeds, of order 10$^{-4.6}$. In this communication, I will argue that this is the first experiment to test Einstein's theory for the (weak) gravity field of Earth, with the result that the neutrinos propagated (just) luminally.

  3. Comments on redefinition of SI units based on fundamental physical constants with fixed values

    CERN Document Server

    Khruschov, V V

    2011-01-01

    Advantages and disadvantages of fixation of fundamental physical constants' values for definition of SI units are considered. The case with a new definition of the mass unit on the base of a fixed value of the Avogadro constant is studied in detail. Criteria on choosing of a optimum FPC set with fixed values for the redefinition of the SI units are suggested. The minimal optimum FPC set that is consistent with the criteria is presented. The set comprises the speed of light, the constant of the ground state hyperfine transition of the caesium-133 atom, the Avogadro constant, the mass of the carbon-12 atom and the absolute magnitude of the electron charge. Comment on the redefinition of the kelvin is also made.

  4. A strontium lattice clock with $3 \\times 10^{-17}$ inaccuracy and its frequency

    CERN Document Server

    Falke, Stephan; Grebing, Christian; Lipphardt, Burghard; Weyers, Stefan; Gerginov, Vladislav; Huntemann, Nils; Hagemann, Christian; Al-Masoudi, Ali; Häfner, Sebastian; Vogt, Stefan; Sterr, Uwe; Lisdat, Christian

    2013-01-01

    We have measured the absolute frequency of the optical lattice clock based on $^{87}$Sr at PTB with an uncertainty of $3.9\\times 10^{-16}$ using two caesium fountain clocks. This is close to the accuracy of today's best realizations of the SI second. The absolute frequency of the 5s$^2$ $^1$S$_0$-5s5p $^3$P$_0$ transition in $^{87}$Sr is 429,228,004,229,873.13(17) Hz. Our result is in excellent agreement with recent measurements performed in different laboratories worldwide. We improved the total systematic uncertainty of our Sr frequency standard by a factor of five and reach $3\\times 10^{-17}$, opening new prospects for frequency ratio measurements between optical clocks for fundamental research, geodesy, or optical clock evaluation.

  5. THE LATEST DEVELOPMENT OF ATOMIC-OPTICS%原子光学的最新发展——光的群速度在铯原子气体中可达到真空中光速的310倍

    Institute of Scientific and Technical Information of China (English)

    卢光山; 邓冬梅; 郭弘

    2001-01-01

    The latest development of research on the light pulse propagation is introduced. L J Wang et al. used the gain- assisted linear anomalous dispersion to demonstate superluminal light propagation in atomic caesium gas. He showed that the group velocity of a laser pulse in this region exceeds c and can even become negative: vg = -310(±5)c while the shape of the pulse is preserved.%主要介绍光脉冲传输研究方面的最新发展动态,Wang L J等人[1]利用辅助增益线性反常色散证实了通过铯原子气体的激光脉冲群速vg可以达到-310(±5)c,同时脉冲的波形也得到了完好的保存.

  6. Loading of a fountain clock with an enhanced Low-Velocity Intense Source of atoms

    CERN Document Server

    Dobrev, Georgi; Weyers, Stefan

    2016-01-01

    We present experimental work for improved atom loading in the optical molasses of a caesium fountain clock, employing a low-velocity intense source of atoms (LVIS) [Lu et al., Phys. Rev. Lett. 77, 3331 (1996)], which we modified by adding a "dark" state pump laser. With this modification the atom source has a mean flux of $4 \\times 10^{8}$ atoms/s at a mean atom velocity of $8.6$ m/s. Compared to fountain operation using background gas loading, we achieved a significant increase of the loaded and detected atom number by a factor of 40. Operating the fountain clock with a total number of detected atoms $N_{\\mathrm{at}}=2.9 \\times 10^6$ in the quantum projection noise-limited regime, a frequency instability $\\sigma_y\\left(1\\text{s}\\right)=2.7 \\times 10^{-14}$ was demonstrated.

  7. IBIS/PICsIT in-flight performances

    CERN Document Server

    Cocco, G D; Celesti, E; Foschini, L; Gianotti, F; Labanti, C; Malaguti, G; Mauri, A; Rossi, E; Schiavone, F; Spizzichino, A; Stephen, J B; Traci, A; Trifoglio, M

    2003-01-01

    PICsIT (Pixellated Imaging CaeSium Iodide Telescope) is the high energy detector of the IBIS telescope on-board the INTEGRAL satellite. PICsIT operates in the gamma-ray energy range between 175 keV and 10 MeV, with a typical energy resolution of 10% at 1 MeV, and an angular resolution of 12 arcmin within a \\~100 square degree field of view, with the possibility to locate intense point sources in the MeV region at the few arcmin level. PICsIT is based upon a modular array of 4096 independent CsI(Tl) pixels, ~0.70 cm^2 in cross-section and 3 cm thick. In this work, the PICsIT on-board data handling and science operative modes are described. This work presents the in-flight performances in terms of background count spectra, sensitivity limit, and imaging capabilities.

  8. Towards a Re-definition of the Second Based on Optical Atomic Clocks

    CERN Document Server

    Riehle, Fritz

    2015-01-01

    The rapid increase in accuracy and stability of optical atomic clocks compared to the caesium atomic clock as primary standard of time and frequency asks for a future re-definition of the second in the International System of Units (SI). The status of the optical clocks based on either single ions in radio-frequency traps or on neutral atoms stored in an optical lattice is described with special emphasis of the current work at the Physikalisch-Technische Bundesanstalt (PTB). Besides the development and operation of different optical clocks with estimated fractional uncertainties in the 10^-18 range, the supporting work on ultra-stable lasers as core elements and the means to compare remote optical clocks via transportable standards, optical fibers, or transportable clocks is reported. Finally, the conditions, methods and next steps are discussed that are the prerequisites for a future re-definition of the second.

  9. In Situ Characterisation of an Optically Thick Atom-Filled Cavity

    CERN Document Server

    Munns, J H D; Ledingham, P M; Walmsley, I A; Nunn, J; Saunders, D J

    2015-01-01

    A means for precise experimental characterization of the dielectric susceptibility of an atomic gas inside and optical cavity is important for design and operation of quantum light matter interfaces, particularly in the context of quantum information processing. Here we present a numerically optimised theoretical model to predict the spectral response of an atom-filled cavity, accounting for both homogeneous and inhomogeneous broadening at high optical densities. We investigate the regime where the two broadening mechanisms are of similar magnitude, which makes the use of common approximations invalid. Our model agrees with an experimental implementation with warm caesium vapour in a ring cavity. From the cavity response, we are able to extract important experimental parameters, for instance the ground state populations, total number density and the magnitudes of both homogeneous and inhomogeneous broadening.

  10. A diode laser spectrometer at 634 nm and absolute frequency measurements using optical frequency comb

    Institute of Scientific and Technical Information of China (English)

    Yi Lin; Yuan Jie; Qi Xiang-Hui; Chen Wen-Lan; Zhou Da-Wei; Zhou Tong; Zhou Xiao-Ji; Chen Xu-Zong

    2009-01-01

    This paper reports that two identical external-cavity-diode-laser(ECDL)based spectrometers are constructed at 634 nm referencing on the hyperfine B-X transition a(80)8-4 of 127I2.The lasers are stabilized on the Doppler-free absorption signals using the third-harmonic detection technique.The instability of the stabilized laser is measured to be 2.8×10-12(after 1000 s)by counting the beat note between the two lasers.The absolute optical frequency of the transition is,for the first time,determined to be 472851936189.5 kHz by using an optical frequency comb referenced on the microwave caesium atomic clock.The uncertainty of the measurement is less than 4.9 kHz.

  11. Redetermination of the hexagonal struvite analogue Cs[Mg(OH26](PO4

    Directory of Open Access Journals (Sweden)

    Matthias Weil

    2008-08-01

    Full Text Available The structure of the hexagonal modification of caesium hexaaquamagnesium phosphate has been redetermined from single-crystal X-ray data. The previous refinement from photographic data [Ferrari, Calvaca & Nardelli (1955. Gazz. Chim. Ital. 85, 1232–1238] was basically confirmed, but with all H atoms located and with all non H-atoms refined with anisotropic displacement parameters. The structure can be derived from the NiAs structure type: the PO4 tetrahedra (3m. symmetry are on the Ni positions and the complex [Mg(OH26] octahedra (3m. symmetry are on the As positions. The building units are connected to each other by hydrogen bonds. The Cs+ cations (3m. symmetry are located in the voids of this arrangement and exhibit a distorted cuboctahedral 12-coordination by the O atoms of the water molecules.

  12. Recoil Effects in Microwave Ramsey Spectroscopy

    CERN Document Server

    Wolf, P; Wolf, Peter; Borde, Christian J.

    2004-01-01

    We present a theory of recoil effects in two zone Ramsey spectroscopy, particularly adapted to microwave frequency standards using laser cooled atoms. We describe the atoms by a statistical distribution of Gaussian wave packets which enables us to derive and quantify effects that are related to the coherence properties of the atomic source and that have not been considered previously. We show that, depending on the experimental conditions, the expected recoil frequency shift can be partially cancelled by these effects which can be significant at microwave wavelengths whilst negligible at optical ones. We derive analytical expressions for the observed interference signal in the weak field approximation, and numerical results for realistic caesium fountain parameters. In the near future Cs and Rb fountain clocks are expected to reach uncertainties which are of the same order of magnitude (10^{-16}) as first estimates of the recoil shift at microwave frequencies. We show, however, that the partial cancellation p...

  13. Comparative study of alkali-vapour cells with alkane-, alkeneand 1-nonadecylbenzene-based antirelaxation wall coatings

    Energy Technology Data Exchange (ETDEWEB)

    Balabas, M V; Tretiak, O Yu [Department of Physics, Saint-Petersburg State University (Russian Federation)

    2013-12-31

    The dependence of both longitudinal and transverse relaxation times of ground-state magnetic polarisation in alkali atoms on the coating temperature is experimentally studied for the first time in a rubidium-vapour cell with 1-nonadecylbenzene antirelaxation coating of inner walls. The comparison of these times with the relaxation times in a caesium-vapour cell with alkane wall coatings is presented. It is found that within the studied temperature range (294 – 340K) the transverse relaxation time decreases with increasing temperature of alkene and 1-nonadecylbenzene coatings. For the alkane coating such a dependence was not explicitly found. The longitudinal relaxation time begins to decrease in all cases when passing a certain critical temperature of the coating material. It is found that the unsaturated radical structure of the coating material molecules strongly affects its antirelaxation properties. (optical pumping)

  14. Ramsey-comb spectroscopy with intense ultrashort laser pulses

    CERN Document Server

    Morgenweg, Jonas; Eikema, Kjeld S E

    2014-01-01

    Optical frequency combs based on mode-locked lasers have revolutionised the field of metrology and precision spectroscopy by providing precisely calibrated optical frequencies and coherent pulse trains. Amplification of the pulsed output from these lasers is very desirable, as nonlinear processes can then be employed to cover a much wider range of transitions and wavelengths for ultra-high precision, direct frequency comb spectroscopy. Therefore full repetition rate laser amplifiers and enhancement resonators have been employed to produce up to microjoule-level pulse energies. Here we show that the full frequency comb accuracy and resolution can be obtained by using only two frequency comb pulses amplified to the millijoule pulse energy level, orders of magnitude more energetic than what has previously been possible. The novel properties of this approach, such as cancellation of optical light-shift effects, is demonstrated on weak two-photon transitions in atomic rubidium and caesium, thereby improving the fr...

  15. Compton back scatter imaging for mild steel rebar detection and depth characterization embedded in concrete

    Science.gov (United States)

    Margret, M.; Menaka, M.; Venkatraman, B.; Chandrasekaran, S.

    2015-01-01

    A novel non-destructive Compton scattering technique is described to ensure the feasibility, reliability and applicability of detecting the reinforcing steel bar in concrete. The indigenously developed prototype system presented in this paper is capable of detecting the reinforcement of varied diameters embedded in the concrete and as well as up to 60 mm depth, with the aid of Caesium-137(137Cs) radioactive source and a high resolution HPGe detector. The technique could also detect the inhomogeneities present in the test specimen by interpreting the material density variation caused due to the count rate. The experimental results are correlated using established techniques such as radiography and rebar locators. The results obtained from its application to locate the rebars are quite promising and also been successfully used for reinforcement mapping. This method can be applied, especially when the intrusion is located underneath the cover of the concrete or considerably at larger depths and where two sided access is restricted.

  16. Volume and Surface-Enhanced Volume Negative Ion Sources

    CERN Document Server

    Stockli, M P

    2013-01-01

    H- volume sources and, especially, caesiated H- volume sources are important ion sources for generating high-intensity proton beams, which then in turn generate large quantities of other particles. This chapter discusses the physics and technology of the volume production and the caesium-enhanced (surface) production of H- ions. Starting with Bacal's discovery of the H- volume production, the chapter briefly recounts the development of some H- sources, which capitalized on this process to significantly increase the production of H- beams. Another significant increase was achieved in the 1990s by adding caesiated surfaces to supplement the volume-produced ions with surface-produced ions, as illustrated with other H- sources. Finally, the focus turns to some of the experience gained when such a source was successfully ramped up in H- output and in duty factor to support the generation of 1 MW proton beams for the Spallation Neutron Source.

  17. Fundamental studies on the Cs dynamics under ion source conditions

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, R., E-mail: roland.friedl@physik.uni-augsburg.de; Fantz, U. [AG Experimentelle Plasmaphysik (EPP), Institute of Physics, University of Augsburg, 86135 Augsburg (Germany); Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstraße 2, 85748 Garching (Germany)

    2014-02-15

    The performance of surface conversion based negative hydrogen ion sources is mainly determined by the caesium dynamics. Therefore, fundamental investigations in vacuum and plasma are performed at a flexible laboratory setup with ion source parameters. Studies on the influence of Cs on the plasma parameters of H{sub 2} and D{sub 2} plasmas showed that n{sub e} and T{sub e} in the bulk plasma are not affected by relevant amounts of Cs and no isotopic differences could be observed. The coating of the vessel surfaces with Cs, however, leads to a considerable gettering of hydrogen atoms from the plasma volume and to the decrease of n{sub e} close to a sample surface due to the formation of negative ions.

  18. Fuel and fission product behaviour in early phases of a severe accident. Part I: Experimental results of the PHEBUS FPT2 test

    Energy Technology Data Exchange (ETDEWEB)

    Barrachin, M., E-mail: marc.barrachin@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, B.P. 3, 13115 Saint Paul-lez-Durance Cedex (France); Gavillet, D. [Paul Scherrer Institute, Würenlingen and Villigen, CH-5232 Villigen PSI (Switzerland); Dubourg, R. [Institut de Radioprotection et de Sûreté Nucléaire, B.P. 3, 13115 Saint Paul-lez-Durance Cedex (France); De Bremaecker, A. [Institute for Nuclear Materials Sciences, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)

    2014-10-15

    One objective of the FPT2 test of the PHEBUS FP Program was to study the degradation of an irradiated UO{sub 2} fuel test section and the fission product behaviour under conditions of low steam flow. The results of the post-irradiation examinations (PIE) at the upper levels (823 and 900 mm) of the 1-m long test section are presented in this paper. Material interactions leading to local corium formation were identified: firstly between fuel and Zircaloy-4 cladding, notably at 823 mm, where the cladding melting temperature was reached, and secondly between fuel and stainless steel oxides. Regarding fission products, molybdenum left so-called metallic precipitates mainly composed of ruthenium. Xenon and caesium behave similarly whereas barium and molybdenum often seems to be associated in precipitates.

  19. Synthesis and characterization of low work function alkali oxide thin films for unconventional thermionic energy converters

    Science.gov (United States)

    Giorgis, V.; Morini, F.; Zhu, T.; Robillard, J.-F.; Wallart, X.; Codron, J.-L.; Dubois, E.

    2016-11-01

    In this work, we present the synthesis and the characterization of low work function thin films for Micro Thermionic Converters (MTC). The objective is producing a device operating at relatively low temperature (caesium oxides. Our choice to exploit those materials relies on their low work function and their abundance. For both materials, we present the results on the synthesis of the oxides under high vacuum and controlled temperature. The oxide thin films were characterized by X-ray photoelectron spectroscopy, photoemission, and thermionic emission measurements. By exploiting the latter technique, a quantitative evaluation of the current density, emitted by the heated oxides, is obtained as a function of temperature. Our results demonstrate that it is possible to decrease the silicon work function by almost 3 eV, enabling significant thermionic currents despite relatively low temperatures (below 850 K).

  20. Analysis of NTSC's Timekeeping Hydrogen Masers

    Science.gov (United States)

    Song, H. J.; Dong, S. W.; Wang, Z. M.; Qu, L. L.; Jing, Y. J.; Li, W.

    2015-11-01

    In this article, the hydrogen masers were tested in NTSC (National Time Service Center) keeping time laboratory. In order to avoid the impact of larger noise of caesium atomic clocks, TA(k) or UTC(k) was not used as reference, and four hydrogen masers were mutually referred and tested. The frequency stabilities of hydrogen masers were analyzed by using four-cornered hat method, and the Allan standard deviation of single hydrogen maser was estimated in different sampling time. Then according to the characteristics of hydrogen masers, by removing the trend term, excluding outliers, and smoothing data with mathematical methods to separate the Gaussian noise of hydrogen masers, and finally through the normal Kolmogorov-Smirnov test, a single hydrogen maser's Gaussian noise has been estimated.

  1. Remote atomic clock synchronization via satellites and optical fibers

    CERN Document Server

    Piester, D; Fujieda, M; Feldmann, T; Bauch, A

    2011-01-01

    In the global network of institutions engaged with the realization of International Atomic Time (TAI), atomic clocks and time scales are compared by means of the Global Positioning System (GPS) and by employing telecommunication satellites for two-way satellite time and frequency transfer (TWSTFT). The frequencies of the state-of-the-art primary caesium fountain clocks can be compared at the level of 10e-15 (relative, 1 day averaging) and time scales can be synchronized with an uncertainty of one nanosecond. Future improvements of worldwide clock comparisons will require also an improvement of the local signal distribution systems. For example, the future ACES (atomic clock ensemble in space) mission shall demonstrate remote time scale comparisons at the uncertainty level of 100 ps. To ensure that the ACES ground instrument will be synchronized to the local time scale at PTB without a significant uncertainty contribution, we have developed a means for calibrated clock comparisons through optical fibers. An un...

  2. Microwave lensing frequency shift of the PHARAO laser-cooled microgravity atomic clock

    Science.gov (United States)

    Peterman, Phillip; Gibble, Kurt; Laurent, Phillipe; Salomon, Christophe

    2016-04-01

    We evaluate the microwave lensing frequency shift of the microgravity laser-cooled caesium clock PHARAO. We find microwave lensing frequency shifts of δν/ν  =  11  ×  10-17 to 13  ×  10-17, larger than the shift of typical fountain clocks. The shift has a weak dependence on PHARAO parameters, including the atomic temperature, size of the atomic cloud, detection laser intensities, and the launch velocity. We also find the lensing frequency shift to be insensitive to selection and detection spatial inhomogeneities and the expected low-frequency vibrations. We conservatively assign a nominal microwave lensing frequency uncertainty of  ±4  ×  10-17.

  3. Coherent backscattering of light off one-dimensional atomic strings

    CERN Document Server

    Sørensen, H L; Kluge, K W; Iakoupov, I; Sørensen, A S; Müller, J H; Polzik, E S; Appel, J

    2016-01-01

    Bragg scattering, well known in crystallography, has become a powerful tool for artificial atomic structures such as optical lattices. In an independent development photonic waveguides have been used successfully to boost quantum light-matter coupling. We combine these two lines of research and present the first experimental realisation of coherent Bragg scattering off a one-dimensional (1D) system - two strings of atoms strongly coupled to a single photonic mode - realised by trapping atoms in the evanescent field of a tapered optical fibre (TOF), which also guides the probe light. We report nearly 12% power reflection from strings containing only about one thousand caesium atoms, an enhancement of more than two orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fibre connection between several distant 1D atomic crystals.

  4. First experiments with Cs doped Mo as surface converter for negative hydrogen ion sources

    Science.gov (United States)

    Schiesko, L.; Cartry, G.; Hopf, C.; Höschen, T.; Meisl, G.; Encke, O.; Heinemann, B.; Achkasov, K.; Amsalem, P.; Fantz, U.

    2015-08-01

    A study was conducted on the properties of molybdenum implanted with caesium as an approach to reduce the Cs consumption of negative hydrogen ion sources based on evaporated Cs. The depth profiles of the implanted Cs were simulated by SDTrimSP and experimentally determined by X-ray photoelectron spectroscopy depth profiling. In particular, one year after implantation, the depth profiles showed no signs of Cs diffusion into the molybdenum, suggesting long term stability of the implanted Cs atoms. The H- surface generation mechanisms on the implanted samples in hydrogen plasma were investigated, and the stability of the H- yield during four hours low power hydrogen plasma discharges was demonstrated. An estimation of the work function reduction (-0.8 eV) by the Cs implantation was performed, and a comparison of the relative negative ion yields between the implanted samples and highly oriented pyrolitic graphite showed that the Cs doped Mo negative ion yield was larger.

  5. Plastic optical fibre sensor for in-vivo radiation monitoring during brachytherapy

    Science.gov (United States)

    Woulfe, P.; Sullivan, F. J.; Lewis, E.; O'Keeffe, S.

    2015-09-01

    An optical fibre sensor is presented for applications in real-time in-vivo monitoring of the radiation dose a cancer patient receives during seed implantation in Brachytherapy. The sensor is based on radioluminescence whereby radiation sensitive scintillation material is embedded in the core of a 1mm plastic optical fibre. Three scintillation materials are investigated: thallium-doped caesium iodide (CsI:Tl), terbium-doped gadolinium oxysulphide (Gd2O2S:Tb) and europium-doped lanthanum oxysulphide (La2O2S:Eu). Terbium-doped gadolinium oxysulphide was identified as being the most suitable scintillator and further testing demonstrates its measureable response to different activities of Iodine-125, the radio-active source commonly used in Brachytherapy for treating prostate cancer.

  6. Indirect Relativistic Effect in Electron-Alkali-Atom Collision

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-Bao; PANG Wen-Ning; DING Hai-Bing; SHANG Ren-Cheng

    2005-01-01

    @@ We present detailed studies on the differential cross section (DCS) and total cross section (TCS) in electronalkali-atom collision processes by using two types of distorted wave methods, the ordinary distorted wave method and the indirect-relativistic distorted wave method. We find that the indirect relativistic effect in the target atom can be neglected in the TCS calculation in the processes; however, with an increase of the atomic number, this effect becomes significant in the DCS calculation. Then, based on the density matrix theory, the orientation and alignment parameters of excited caesium P states scattered by electrons at low incident energy are calculated,and comparisons are made for the two series between the two methods. The results show that accordance is reached at scattering angles smaller than 45°, but considerable difference appears at angles larger than 45° due to the relativistic effect.

  7. Ultra-narrow bandwidth optical filters consisting of one-dimensional photonic crystals with anomalous dispersion materials

    Institute of Scientific and Technical Information of China (English)

    Liu Jiang-Tao; Zhou Yun-Song; Wang Fu-He; Gu Ben-Yuan

    2005-01-01

    We present a new type of optical filter with an ultra-narrow bandwidth and a wide field-of-view (FOV). This kind of optical filter consists of one-dimensional photonic crystal (PC) incorporating an anomalous-dispersion-material (ADM) with, for instance, an anomalous dispersion of 6P3/2 ← 6S1/2 hyperfine structure transition of a caesium atom.The transmission spectra of optical filters are calculated by using the transfer-matrix method. The simulation results show that the designed optical filter has a bandwidth narrower than 0.33GHz and a wide FOV of ±30° as well. The response of transmission spectrum to an external magnetic field is also investigated.

  8. Crystal structure of CsCrAs2O7, a new member of the diarsenate family

    Directory of Open Access Journals (Sweden)

    Mohamad Alem Bouhassine

    2015-06-01

    Full Text Available Caesium chromium(III diarsenate(V, CsCrAs2O7, was prepared by solid-state reactions. The title structure consists of isolated CrO6 octahedra and As2O7 diarsenate groups, sharing corners to build up a three-dimensional [CrAs2O7]− anionic framework. In this framework, channels extending parallel to [001] are present in which the ten-coordinate Cs+ ions reside. CsCrAs2O7 is isotypic with the monoclinic AIMIIIX2O7 (AI = alkali metal; MIII = Al, Cr, Fe; X = As, P type I family of compounds crystallizing in the space group P21/c.

  9. Efeitos biológicos das radiações ionizantes: acidente radiológico de Goiânia

    Directory of Open Access Journals (Sweden)

    Emico Okuno

    2013-01-01

    Full Text Available Neste artigo apresentamos as bases da Física das radiações, as fontes naturais e artificiais, os efeitos biológicos, a proteção radiológica. Examinamos também a sequência de eventos que resultou no acidente de Goiânia com uma fonte de césio-137 de um equipamento de radioterapia abandonado e suas terríveis consequências.This article presents the fundaments of radiation physics, the natural and artificial sources, biological effects, radiation protection. We also examine the sequence of events that resulted in Goiania accident with a source of caesium-137 from abandoned radiotherapy equipment and its terrible consequences.

  10. Limits on gravitational Einstein equivalence principle violation from monitoring atomic clock frequencies during a year

    Science.gov (United States)

    Dzuba, V. A.; Flambaum, V. V.

    2017-01-01

    The Sun's gravitational potential at Earth varies during a year due to varying Earth-Sun distance. Comparing the results of very accurate measurements of atomic clock transitions performed at different times in the year allows us to study the dependence of the atomic frequencies on the gravitational potential. We examine the measurement data for the ratio of the frequencies in Hg+ and Al+ clock transitions and absolute frequency measurements (with respect to the caesium frequency standard) for Dy, Sr, H, hyperfine transitions in Rb and H and obtain significantly improved limits on the values of the gravity-related parameter of the Einstein equivalence principle violating term in the electron sector of the Standard Model extension Hamiltonian c00=(-3.0 ±5.7 )×10-7 and the parameter for the gravity-related variation of the fine structure constant κα=(-5.3 ±10 )×10-8.

  11. Single mode quadrature entangled light from room temperature atomic vapour

    CERN Document Server

    Wasilewski, W; Jensen, K; Madsen, L S; Krauter, H; Polzik, E S

    2009-01-01

    We analyse a novel squeezing and entangling mechanism which is due to correlated Stokes and anti-Stokes photon forward scattering in a multi-level atom vapour. Following the proposal we present an experimental demonstration of 3.5 dB pulsed frequency nondegenerate squeezed (quadrature entangled) state of light using room temperature caesium vapour. The source is very robust and requires only a few milliwatts of laser power. The squeezed state is generated in the same spatial mode as the local oscillator and in a single temporal mode. The two entangled modes are separated by twice the Zeeman frequency of the vapour which can be widely tuned. The narrow-band squeezed light generated near an atomic resonance can be directly used for atom-based quantum information protocols. Its single temporal mode characteristics make it a promising resource for quantum information processing.

  12. Impact of gamma rays exposure and growth regulators on Oryza sativa L. c.v MR269 callus induction

    Science.gov (United States)

    Kadhimi, Ahsan A.; Zain, Che Radziah Che Mohd; Alhasnawi, Arshad Naji; Isahak, Anizan; Ashraf, Mehdi Farshad; Mohamad, Azhar; Doni, Febri; Yusoff, Wan Mohtar Wan

    2016-11-01

    The study is aimed to evaluate in vitro somatic embryogenesis to gamma ray exposure and the use of growth regulators to mature embryos explants for rice callus induction. Seeds of local rice genotype (MR269) were exposed to gamma rays at 350 Gy (Source: Caesium-137). Matured embryos were cultured to induce callus on Murashige and Skoog (MS) supplemented at different concentrations of 1.0, 2.0, 3.0 mg/L 2.4-D and 0.1 and 0.2 mg/L Kinetin for 4 weeks. Callus induction and callus fresh weight were decreased after exposure to gamma ray. The most efficient response to callus induction and callus fresh weight was found at 3 mg/L 2,4-D and 0.1 mg/L kinetin.

  13. Optical Stabilization of a Microwave Oscillator for Fountain Clock Interrogation

    CERN Document Server

    Lipphardt, Burghard; Weyers, Stefan

    2016-01-01

    We describe an optical frequency stabilization scheme of a microwave oscillator that is used for the interrogation of primary caesium fountain clocks. Because of its superior phase noise properties, the new scheme, which is based on an ultrastable laser and a femtosecond laser frequency comb, overcomes the fountain clock frequency instability limitations given by the previously utilized quartz oscillator based frequency synthesis. The presented scheme combines the transfer of the short-term frequency instability of an optical cavity and the long-term frequency instability of a hydrogen maser to the microwave oscillator and is designed to provide continuous long-term operation for extended measurement periods of weeks. The utilization of the twofold stabilization scheme on the one hand ensures referencing of the fountain frequency to the hydrogen maser frequency and on the other hand results in a phase noise level of the fountain interrogation signal, which enables quantum projection noise limited fountain fre...

  14. Limits on gravitational Einstein Equivalence Principle violation from monitoring atomic clock frequencies during a year

    CERN Document Server

    Dzuba, V A

    2016-01-01

    Sun's gravitation potential at earth varies during a year due to varying Earth-Sun distance. Comparing the results of very accurate measurements of atomic clock transitions performed at different time in the year allows us to study the dependence of the atomic frequencies on the gravitational potential. We examine the measurement data for the ratio of the frequencies in Hg$^+$ and Al$^+$ clock transitions and absolute frequency measurements (with respect to caesium frequency standard) for Dy, Sr, H, hyperfine transitions in Rb and H, and obtain significantly improved limits on the values of the gravity related parameter of the Einstein Equivalence Principle violating term in the Standard Model Extension Hamiltonian $c_{00} = (3.0 \\pm 5.7) \\times 10^{-7}$ and the parameter for the gravity-related variation of the fine structure constant $\\kappa_{\\alpha} = (-5.3 \\pm 10) \\times 10^{-8}$.

  15. Crystal structure of Cs2[Th(NO36

    Directory of Open Access Journals (Sweden)

    Patrick Woidy

    2014-08-01

    Full Text Available Dicaesium hexanitratothorate(IV, Cs2[Th(NO36], was synthesized in the form of colourless crystals by reaction of thorium nitrate and caesium nitrate in aqueous solution. The Th atom is located on an inversion centre and is coordinated by six chelating nitrate anions. The resulting ThO12 coordination polyhedron is best described as a slightly distorted icosahedron. The Cs atom also has a coordination number of 12, but its coordination polyhedron is considerably more distorted. The crystal packing can be derived from an hexagonal dense packing (hcp of idealized spherical CsO12 and ThO12 units. The CsO12 units form a distorted hcp arrangement and half of the octahedral sites are occupied by the ThO12 units.

  16. Single-photon-level quantum memory at room temperature

    CERN Document Server

    Reim, K F; Lee, K C; Nunn, J; Langford, N K; Walmsley, I A

    2010-01-01

    Quantum memories capable of storing single photons are essential building blocks for quantum information processing, enabling the storage and transfer of quantum information over long distances. Devices operating at room temperature can be deployed on a large scale and integrated into existing photonic networks, but so far warm quantum memories have been susceptible to noise at the single photon level. This problem is circumvented in cold atomic ensembles, but these are bulky and technically complex. Here we demonstrate controllable, broadband and efficient storage and retrieval of weak coherent light pulses at the single-photon level in warm atomic caesium vapour using the far off-resonant Raman memory scheme. The unconditional noise floor is found to be low enough to operate the memory in the quantum regime at room temperature.

  17. Cementation of the medium-activity AMOR waste solution at VKTA Rossendorf with the MOSS-200 mobile plant

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, F.; Pfefferkorn, G. [Nuclear Process Engineering and Analysis Association Rossendorf e. V. (VKTA), Dresden (Germany); Ekberg, A. [Westinghouse Atom AB, Vaesteras (Sweden); Mika, S. [Westinghouse Reaktor GmbH, Mannheim (Germany)

    2001-07-01

    Molybdenum-99 has been isolated since 1985 at the former Central Institute for Nuclear Research at Rossendorf from aluminium-clad fuel assemblies exposed in the research reactor for production of technetium-99m generators. The Rossendorf molybdenum production plant operated for this (abbreviated to AMOR - a German acronym), consisted of three plant sections. Plant section AMOR I was responsible for the resolution process and molybdenum extraction. Plant AMOR II was used for nuclear fuel recovery from AMOR-I waste solution by liquid-liquid extraction, and plant AMOR III was responsible for reprocessing the AMOR-II extract. The entire AMOR plant was shut down in late 1990. Radiologically, the residue from AMOR production can be classified as medium-activity liquid waste with the most important radioactive constituents being the two isotopes strontium-90 and caesium-137. Chemically, the waste consists of highly acidic (nitric acid) solution containing aluminium nitrate. (orig.)

  18. Corrosion of irradiated MOX fuel in presence of dissolved H 2

    Science.gov (United States)

    Carbol, P.; Fors, P.; Van Winckel, S.; Spahiu, K.

    2009-07-01

    The corrosion behaviour of irradiated MOX fuel (47 GWd/tHM) has been studied in an autoclave experiment simulating repository conditions. Fuel fragments were corroded at room temperature in a 10 mM NaCl/2 mM NaHCO 3 solution in presence of dissolved H 2 for 2100 days. The results show that dissolved H 2 in concentration 1 mM and higher inhibits oxidation and dissolution of the fragments. Stable U and Pu concentrations were measured at 7 × 10 -10 and 5 × 10 -11 M, respectively. Caesium was only released during the first two years of the experiment. The results indicate that the UO 2 matrix of a spent MOX fuel is the main contributor to the measured dissolution, while the corrosion of the high burn-up Pu-rich islands appears negligible.

  19. Geology of outer Horns Rev, Danish North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Joern B.; Gravesen, P.; Lomholt, S. (Geological Survey of Denmark and Greenland, Copenhagen (Denmark))

    2008-07-15

    In 2006, Dong Energy initiated the development of the Horns Rev II offshore wind farm in the North Sea. In order to evaluate and map the characteristics of the surface features of the sea bed and to characterise the subsurface in the wind farm area, the Geological Survey of Denmark and Greenland (GEUS) conducted a geophysical survey of the area. The survey utilised a variety of instruments: sparker, side-scan sonar, marine caesium magnetometer and a multibeam echo-sounder. In addition, information on the subsurface sediments was obtained by cone penetration tests (CPT) and by drilling to 30-50 m below the sea bottom. Geological correlation of the CPT results with the other survey results was extremely complicated but was required in order to understand the architecture of the ice marginal glaciotectonic complex. Information on the geology is crucial for evaluation of the geotechnical problems of the region. (au)

  20. Geographical redistribution of radionuclides in forest and wetland

    Energy Technology Data Exchange (ETDEWEB)

    Tjaernhage, Aasa; Plamboeck, Agnetha; Nylen, Torbjoern; Lidstroem, Kenneth; Aagren, Goeran; Lindgren, Jonas

    2000-12-01

    This report summarizes the results from a survey concerning the presence of caesium-137 in soil in two different areas, Verkmyraan in Gaestrikland and Nyaenget in Vaesterbotten. This has been done with a portable NaI gamma spectrometer connected to a GPS, called back pack. Soil samples have also been taken in the two areas to compare the results from these with the back pack measurements. The results from a survey of Cesium-137 1989 in Nyaenget has also been included to see if there has been a redistribution of Cs-137 in the area in the last ten years. At Verkmyraan there is an increase in Cs-137 deposition at the lower part of the catchment which probably depends on a transport of Cs-137 to the outflow. In Nyaenget the results show a possible levelling of the Cs-137 activity between the different soil types, but to verify that, more soil samples must be taken and analysed.

  1. RESUME95 Nordic field test of mobile equipment for nuclear fall-out monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, C.; Bresson, J.; Chiffot, T.; Guillot, L. [Centre d`Etudes de Valduc, Direction des Applications Militaires, Commissaiat a L`Energie Atomique, Tille (France)

    1997-12-31

    Nordic Safety Research (NKS) organised in August 1995 a field test of various techniques and instrumentation for monitoring radioactive fall-out. In an emergency situation, after a major release of radioactive material, many different measuring systems are going to be used, ranging from small hand hold intensitometer to complex spectrometer systems. In this test the following type of equipment were tested: Airborne spectrometers; Carborne spectrometers and dose rate meters; In situ spectrometers and intensitometers. Helinuc team was equipped of an airborne system and of a germanium device for in situ measurements. Different tasks were specified for each team: Mapping caesium fall-out and natural activity over two areas of 18 and 5 km{sup 2}; Research of hidden sources. For measurements and data processing the respect of time allowed was strictly controlled for testing the ability of each team. (au).

  2. Carborne fallout mapping - STUK/HUT team

    Energy Technology Data Exchange (ETDEWEB)

    Honkamaa, T.; Tiilikainen, H. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Aarnio, P.; Nikkinen, M. [Helsinki Univ. of Technology, Espoo (Finland)

    1997-12-31

    During the summer 1995 altogether 8,625 spectrometric and 3,108 dose-rate measurements were performed in Padasjoki Auttoinen village using carborne measuring devices. As a result {sup 137}Cs fallout and dose-rate maps were produced. The highest measured values in the test area II were 160 kBq m{sup -2} for fallout and 0.22 {mu}Sv h{sup -1} for dose-rate. One hot spot was found beside the test area (dose rate 0.31 {mu}Sv h{sup -1}). On the cultivated areas the measured count rates in {sup 137}Cs-window are three to four times lower than in the forest areas in average, indicating an altered depth profile of caesium. (au).

  3. Detection of hidden sources. Prompt reports by airborne teams in Resume95

    Energy Technology Data Exchange (ETDEWEB)

    Toivonen, H. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1997-12-31

    An exercise to locate and identify lost radioactive sources was arranged near Padasjoki Auttoinen village. Ten sources, consisting of caesium, cobolt, iridium and technetium, were hidden. The teams (10) were asked to report their findings immediately after the landing and 24 h later. The teams that had a large NaI detector at their disposal could locate more sources than the teams with HPGe detectors. However, for source identification and activity calculation and HPGe detector is superior. Thus, it is highly recommended for operational purposes that both measuring systems are used simultaneously. The best location results were provided by the Danish Emergency Management Agency; the team reported four sources at landing and two other sources were found in prompt data processing after the landing. (au).

  4. Dicaesium hexamercury heptasulfide

    Directory of Open Access Journals (Sweden)

    James A. Ibers

    2008-09-01

    Full Text Available The title compound, Cs2Hg6S7, crystallizes in a new structure type that is closely related to that of K2Zn6O7. The structure comprises a three-dimensional mercury sulfide network that is composed of channels. These channels, which are along [001], are of two different diameters. The crystal structure contains one Cs, two Hg, and three S atoms in the asymmetric unit. The Cs, one Hg, and one S atom are at sites of symmetry m, whereas a second S atom is at a site of symmetry 2mm. The Hg atoms are bound to the S atoms in both three- and four-coordinate geometries. The caesium cations occupy the central spaces of the larger diameter channels and exhibit a coordination number of 7.

  5. Japan, one year after. In Fukushima, a decontamination by forced march; Japon, un an apres. A Fukushima, une decontamination a marche forcee

    Energy Technology Data Exchange (ETDEWEB)

    Leglu, D.; Mulot, R.; Khalathari, A.; Lafon, B.; Stanley, T.; Linton, M.

    2012-03-15

    In a first part, the author describes how people living in the contaminated area around Fukushima try to deal with the difficult and almost impossible decontamination of their houses, gardens, schools, and so on. The destruction of forests is planned as they concentrate radioactivity. Thousands of inhabitants must wear dosimeters. An article comments the caesium activity measurements. Several data and figures are presented: evacuation areas, radioactive emissions and releases, doses received by emergency personnel, size of areas to be decontaminated, impact on the Japanese energy sector, contamination rates for soils and seawater, decontamination and dismantling costs, health impacts. An article proposes an overview of the different methods which are implemented and tested by the Japanese for large scale decontamination

  6. Spectroscopic (FT-IR, FT-Raman, UV) and microbiological studies of di-substituted benzoates of alkali metals

    Science.gov (United States)

    Kalinowska, M.; Świsłocka, R.; Borawska, M.; Piekut, J.; Lewandowski, W.

    2008-06-01

    The FT-IR, FT-Raman and UV spectra of 3,5-dihydroxybenzoic and 3,5-dichlorobenzoic acids as well as lithium, sodium, potassium, rubidium, caesium 3,5-dihydroxy- and 3,5-dichlorobenzoates were recorded, assigned and compared. The theoretical geometries, Mulliken atomic charges, IR wavenumbers were obtained in B3LYP/6-311++G** level. On the basis of the gathered experimental and theoretical data the effect of metals and substituents on the electronic system of studied compounds were investigated. Moreover, the antimicrobiological activity of studied compounds against two species of bacteria: Bacillus subtilis, Staphylococus aureus and one species of yeast: Candida albicans were studied after 24 and 48 h of incubation. The attempt was made, to find out whether there is any correlation between the first principal component and the degree of growth inhibition exhibited by studied compounds in relation to selected microorganisms.

  7. The relationship between molecular structure and biological activity of alkali metal salts of vanillic acid: Spectroscopic, theoretical and microbiological studies

    Science.gov (United States)

    Świsłocka, Renata; Piekut, Jolanta; Lewandowski, Włodzimierz

    In this paper we investigate the relationship between molecular structure of alkali metal vanillate molecules and their antimicrobial activity. To this end FT-IR, FT-Raman, UV absorption and 1H, 13C NMR spectra for lithium, sodium, potassium, rubidium and caesium vanillates in solid state were registered, assigned and analyzed. Microbial activity of studied compounds was tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Proteus vulgaris, Bacillus subtilis and Candida albicans. In order to evaluate the dependence between chemical structure and biological activity of alkali metal vanillates the statistical analysis was performed for selected wavenumbers from FT-IR spectra and parameters describing microbial activity of vanillates. The geometrical structures of the compounds studied were optimized and the structural characteristics were determined by density functional theory (DFT) using at B3LYP method with 6-311++G** as basis set. The obtained statistical equations show the existence of correlation between molecular structure of vanillates and their biological properties.

  8. Ion-Pair Complexation with Dibenzo[21]Crown-7 and Dibenzo[24]Crown-8 bis-Urea Receptors.

    Science.gov (United States)

    Mäkelä, Toni; Kiesilä, Anniina; Kalenius, Elina; Rissanen, Kari

    2016-09-26

    Synthesis and ion-pair complexation properties of novel ditopic bis-urea receptors based on dibenzo[21]crown-7 (R(1) ) and dibenzo[24]crown-8 (R(2) ) scaffolds have been studied in the solid state, solution, and gas phase. In a 4:1 CDCl3 /[D6 ]DMSO solution, both receptors clearly show positive heterotropic cooperativity toward halide anions when complexed with Rb(+) or Cs(+) , with the halide affinity increasing in order I(-) caesium complexes. However, Rb(+) and Cs(+) complexes of R(2) show stronger affinities toward all the studied anions compared to the corresponding cationic complexes of R(1) . Similar selectivity of the receptors toward the studied ion pairs was also observed also in the gas phase by competition experiments with mass spectrometry. A total of eight crystal structures with different rubidium and caesium halides and oxyanions were obtained in addition to the crystal structure of R(2) ⋅BaCl2 . The selectivity observed in solution and in the gas phase is explainable by the conformational differences observed in the crystal structures of ion-pair complexes with R(1) and R(2) . In the solid state, R(1) has an open conformation due to the asymmetric crown-ether scaffold, whereas R(2) has a compact, folded conformation. Computational studies of the ion-pair complexes of R(2) show that the interaction energies of the complexes increase in the order CsI

  9. The European programme boris (bioavailability of radionuclides in soils): a global analysis of results

    Energy Technology Data Exchange (ETDEWEB)

    Tamponnet, C.; Martin-Garin, A.; Gonzr, M.A. [Institute of Radioprotection and Nuclear Safety, DPRE/SERLAB, Cadarache, 13 - Saint-Paul-lez-Durance (France); Parekh, N. [Center for Ecology and Hydrology, Merlewood research station, Cumbria (United Kingdom); Vallejo, R.; Sauras, T.; Casadesus, J. [Barcelona Univ., Dept. of Plant Biology (Spain); Plassard, C.; Staunton, S. [Institut National de Recherches Agronomiques (INRA), Soil Science Unit, 34 - Montpellier (France); Norden, M.; Avila, R. [Swedish Radiation Protection Institute, Stockholm (Sweden); Shaw, G.; Wells, C. [Imperial College, Berkshire (United Kingdom)

    2004-07-01

    The ability to predict the consequences of an accidental release of radioactive nuclides relies mainly on the level of understanding of the mechanisms involved in radioactive nuclides interactions with different components of agricultural and natural ecosystems and their formalization into predictive models. Numerous studies and databases about contaminated agricultural and natural areas have been obtained but their use to enhance our prediction ability has been largely limited by their unresolved variability. Such variability seems to stem from an incomplete knowledge about radioactive nuclide interactions with the soil matrix, soil moisture, biological elements in the soil and additional pollutants, which may be found in such soils. In this project, we investigated mainly the role of the biological elements (plants, mycorrhizas, microbes) in: radioactive nuclide sorption/desorption in soils and radioactive nuclide uptake/release by plants. Because of the importance of the chemical nature of the involved radioactive nuclides, we followed the bioavailability of three radioactive nuclides: caesium, strontium, and technetium. The role of one additional non-radioactive pollutant (copper) has been scrutinised. Role of microorganisms (K{sub d} for caesium and strontium in organic soils is much greater in the presence of microorganisms than in their absence), plant physiology (changes in plant physiology affect radionuclide uptake by plants), the presence of mycorrhizal fungi (interferes with the uptake of radionuclides by plants), have been demonstrated. Knowledge acquired from these experiments has been incorporated into two mechanistic models CHEMFAST (a soil Column Heuristic Model of radionuclide Fixation and Solution Transport) and BIORUR specifically modelling radioactive nuclide sorption/desorption from soil matrices and radioactive nuclide uptake by/release from plants. These mechanistic models have been incorporated into an assessment model to enhance its

  10. An overview of BORIS: Bioavailability of Radionuclides in Soils

    Energy Technology Data Exchange (ETDEWEB)

    Tamponnet, C. [Institute of Radioprotection and Nuclear Safety, DEI/SECRE, CADARACHE, B.P. 1, 13108 Saint-Paul-lez-Durance, Cedex (France)], E-mail: christian.tamponnet@irsn.fr; Martin-Garin, A.; Gonze, M.-A. [Institute of Radioprotection and Nuclear Safety, DEI/SECRE, CADARACHE, B.P. 1, 13108 Saint-Paul-lez-Durance, Cedex (France); Parekh, N. [Center for Ecology and Hydrology, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Vallejo, R.; Sauras-Yera, T.; Casadesus, J. [Department of Plant Biology, University of Barcelona, 08028 Barcelona (Spain); Plassard, C.; Staunton, S. [INRA, UMR Rhizosphere and Symbiosis, Place Viala, 34060 Montpellier (France); Norden, M. [Swedish Radiation Protection Institute, 171 16 Stockholm (Sweden); Avila, R. [Facilia AB, Valsgaerdevaegen 12, 168 53 Bromma, Stockholm (Sweden); Shaw, G. [Division of Agricultural and Environmental Sciences University Park, Nottingham NG7 2RD (United Kingdom)

    2008-05-15

    The ability to predict the consequences of an accidental release of radionuclides relies mainly on the level of understanding of the mechanisms involved in radionuclide interactions with different components of agricultural and natural ecosystems and their formalisation into predictive models. Numerous studies and databases on contaminated agricultural and natural areas have been obtained, but their use to enhance our prediction ability has been largely limited by their unresolved variability. Such variability seems to stem from incomplete knowledge about radionuclide interactions with the soil matrix, soil moisture, and biological elements in the soil and additional pollutants, which may be found in such soils. In the 5th European Framework Programme entitled Bioavailability of Radionuclides in Soils (BORIS), we investigated the role of the abiotic (soil components and soil structure) and biological elements (organic compounds, plants, mycorrhiza, and microbes) in radionuclide sorption/desorption in soils and radionuclide uptake/release by plants. Because of the importance of their radioisotopes, the bioavailability of three elements, caesium, strontium, and technetium has been followed. The role of one additional non-radioactive pollutant (copper) has been scrutinised in some cases. Role of microorganisms (e.g., K{sub d} for caesium and strontium in organic soils is much greater in the presence of microorganisms than in their absence), plant physiology (e.g., changes in plant physiology affect radionuclide uptake by plants), and the presence of mycorrhizal fungi (e.g., interferes with the uptake of radionuclides by plants) have been demonstrated. Knowledge acquired from these experiments has been incorporated into two mechanistic models CHEMFAST and BIORUR, specifically modelling radionuclide sorption/desorption from soil matrices and radionuclide uptake by/release from plants. These mechanistic models have been incorporated into an assessment model to enhance

  11. Modelling the dynamics of fish contamination by Chernobyl radiocaesium: an analytical solution based on potassium mass balance.

    Science.gov (United States)

    Koulikov, Alexei O; Meili, Markus

    2003-01-01

    After the sudden fallout from the Chernobyl nuclear accident in 1986, activities and bioaccumulation factors of radiocaesium ((137)Cs, (134)Cs) fluctuated strongly over several years before reaching quasi-equilibrium, with patterns significantly differing among organisms. To model these dynamic relaxation processes based on ecological mechanisms we developed mass balance equations for (137)Cs in an aquatic food chain on the following basis: (a). potassium acts as a biogeochemical analogue ("carrier") of caesium; (b). the concentration of potassium in fish and other animals is effectively constant; (c). the main source of potassium in freshwater fish is the dietary uptake. The model is applicable to linear food chains of any number of trophic levels, while solutions evaluated here include the following food chain compartments: water, invertebrates (fish food), non-piscivorous fish, and piscivorous fish. The activity concentration in the water, which is considered as the secondary source of (137)Cs, is described by multi-component first-order decay function, although two components (fast and slow) are often sufficient to provide agreement with empirical data. In every compartment the turnover rate of caesium is considered as a constant over time. The analytical solution of the model equations describes the (137)Cs activity concentration in every compartment as a series of exponential functions, of which some are derived from the source pattern, and the others determined by the (137)Cs turnover rate in each food chain compartment. The model was tested with post-Chernobyl data from several long-term studies in lakes and provided a reasonable description of important radioecological aspects.

  12. Inverse modelling-based reconstruction of the Chernobyl source term available for long-range transport

    Directory of Open Access Journals (Sweden)

    X. Davoine

    2007-01-01

    Full Text Available The reconstruction of the Chernobyl accident source term has been previously carried out using core inventories, but also back and forth confrontations between model simulations and activity concentration or deposited activity measurements. The approach presented in this paper is based on inverse modelling techniques. It relies both on the activity concentration measurements and on the adjoint of a chemistry-transport model. The location of the release is assumed to be known, and one is looking for a source term available for long-range transport that depends both on time and altitude. The method relies on the maximum entropy on the mean principle and exploits source positivity. The inversion results are mainly sensitive to two tuning parameters, a mass scale and the scale of the prior errors in the inversion. To overcome this hardship, we resort to the statistical L-curve method to estimate balanced values for these two parameters. Once this is done, many of the retrieved features of the source are robust within a reasonable range of parameter values. Our results favour the acknowledged three-step scenario, with a strong initial release (26 to 27 April, followed by a weak emission period of four days (28 April–1 May and again a release, longer but less intense than the initial one (2 May–6 May. The retrieved quantities of iodine-131, caesium-134 and caesium-137 that have been released are in good agreement with the latest reported estimations. Yet, a stronger apportionment of the total released activity is ascribed to the first period and less to the third one. Finer chronological details are obtained, such as a sequence of eruptive episodes in the first two days, likely related to the modulation of the boundary layer diurnal cycle. In addition, the first two-day release surges are found to have effectively reached an altitude up to the top of the domain (5000 m.

  13. Size scaling of negative hydrogen ion sources for fusion

    Science.gov (United States)

    Fantz, U.; Franzen, P.; Kraus, W.; Schiesko, L.; Wimmer, C.; Wünderlich, D.

    2015-04-01

    The RF-driven negative hydrogen ion source (H-, D-) for the international fusion experiment ITER has a width of 0.9 m and a height of 1.9 m and is based on a ⅛ scale prototype source being in operation at the IPP test facilities BATMAN and MANITU for many years. Among the challenges to meet the required parameters in a caesiated source at a source pressure of 0.3 Pa or less is the challenge in size scaling of a factor of eight. As an intermediate step a ½ scale ITER source went into operation at the IPP test facility ELISE with the first plasma in February 2013. The experience and results gained so far at ELISE allowed a size scaling study from the prototype source towards the ITER relevant size at ELISE, in which operational issues, physical aspects and the source performance is addressed, highlighting differences as well as similarities. The most ITER relevant results are: low pressure operation down to 0.2 Pa is possible without problems; the magnetic filter field created by a current in the plasma grid is sufficient to reduce the electron temperature below the target value of 1 eV and to reduce together with the bias applied between the differently shaped bias plate and the plasma grid the amount of co-extracted electrons. An asymmetry of the co-extracted electron currents in the two grid segments is measured, varying strongly with filter field and bias. Contrary to the prototype source, a dedicated plasma drift in vertical direction is not observed. As in the prototype source, the performance in deuterium is limited by the amount of co-extracted electrons in short as well as in long pulse operation. Caesium conditioning is much harder in deuterium than in hydrogen for which fast and reproducible conditioning is achieved. First estimates reveal a caesium consumption comparable to the one in the prototype source despite the large size.

  14. Temperature dependence of the work function of caesiated materials under ion source conditions

    Science.gov (United States)

    Friedl, R.; Fantz, U.

    2015-04-01

    The key parameter for the performance of negative hydrogen ion sources based on surface conversion is the work function of the converter surface. In order to enhance the negative ion yield caesium is introduced into the source which lowers the converter work function upon adsorption. However, the Cs layer is subject to background pressures of 10-7-10-6 mbar and to H2 or D2 low-temperature plasmas which can have a major impact on the resultant work function. In order to determine the work function of caesiated surfaces under ion source relevant conditions and to identify influencing parameters, systematic investigations are performed at the laboratory experiment ACCesS. It is confirmed, that the work function of a sample surface in a vacuum of 10-6 mbar is decreased upon the evaporation and adsorption of caesium. However, the adsorbed layer is determined by the formation of Cs compounds with residual gases from the background pressure leading to an increased work function by about 0.6 eV compared to pure Cs layers. Elevated surface temperatures are beneficial for cleaning and against degradation in absence of Cs evaporation, but no further enhancement of the work function can be achieved by temperatures up to 260 °C if a Cs flux onto the surface is already present. Thus, the minimally achievable work function of a stainless steel surface in ion source relevant vacuum conditions is 2.75 eV. The influence of the substrate material and plasma surface interaction will be investigated next.

  15. Impact of the cord-grass Spartina alterniflora on sedimentary and morphological evolution of tidal salt marshes on the Jiangsu coast, China

    Institute of Scientific and Technical Information of China (English)

    WANG Aijun; GAO Shu; JIA Jianjun

    2006-01-01

    The tidal flats of the Wanggang area, on the Jiangsu coast, represent the largest continuously distributed coastal wetland in terms of area coverage in China, and the dynamics of tidal flat accretion and erosion is highly complicated. The cord-grass Spartina alterniflora, which was introduced artificially into the Jiangsu coast, has significant influences on the regional tidal flat evolution in terms of deposition rate, spacial sediment distribution patterns and tidal creek morphology. On the basis of the data set of bed elevation and accumulation rate for different periods of time, the applicability of the Pethick-Allen model to the Jiangsu tidal salt marshes is discussed. In addition, caesium-137 dating was carried out for sediment samples collected from the salt marsh of the Wangang area. In combination with the caesium-137 analysis and the data collected from literature, the Pethick-Allen model was used to derive the accumulation rate in the Wanggang tidal flat for the various periods. The results show that the pattern of tidal flat accretion has been modified, due to more rapid accretion following the introduction of S.alterniflora to the region. Surficial sediment samples were collected from representative profiles and analyzed for grain size with a laser particle analyzer. The result shows that fine-grained sediment has been trapped by the plant, with most of the sediment deposited on the Suaeda salsa and Spartina angelica flats being derived from drainage creeks rather than the from gently sloping tidal flats. Remote sensing analysis and in situ observations indicate that the creeks formed in the S.alterniflora flat have a relatively small ratio of width to depth, a relatively high density, and are more stable than the other tidal flat creek systems in the study area.

  16. Fluxes of radionuclides in the agricultural production after a nuclear accident: countermeasures and decontamination techniques; Flux des radionucleides dans les productions agricoles suite a un accident nucleaire: contre-mesures et techniques de rehabilitation

    Energy Technology Data Exchange (ETDEWEB)

    Jouve, A. [CEA Centre d`Etudes Nucleaires de Cadarache, 13 -Saint-Paul-lez-Durance (France)]|[Universite de Provence, 13 - Marseille (France)

    1997-12-31

    This thesis deals with the radiological consequences of a nuclear accident through the radioactive contamination of the food chain and the subsequent countermeasures for decreasing the fluxes of radionuclides and decontaminating agricultural lands. After a brief summary of the radioprotection ground and context in case of a nuclear accident, this work surveys existing data on the fluxes of radionuclides in soils and from soil to plants. The research work focuses on both the prediction of the fluxes of radionuclides and possible countermeasures: the measurement of the bioavailability of radionuclides in the soil solution, its use in a mathematical expression to quantify the soil-to-plant transfer of caesium and strontium, and the perspectives of an innovative technique of soil decontamination. The obtained results show that based on 4 coefficients, it is possible to predict crop contamination within a 3 % confidence interval: the fluid solid distribution coefficient of radionuclides kd, the amount of chemical analogues of caesium and strontium, i.e. potassium and calcium, respectively, soil pH and a constant characterising the plant species that is concerned. However, it generally appears from soil to plant transfer studies that the reduction of the fluxes of radionuclides is not a promising way of radiological exposure mitigation after a nuclear accident. The work performed shows that it is more efficient to tackle the source of the contamination, i.e. decontaminate the soil. The proposed technique of soil scraping using a turf harvester appears to be the most advantageous among the tested options, for the decontamination of peat-bog meadows. (author).

  17. {sup 137}Cs and {sup 9}Sr uptake by sunflower cultivated under hydroponic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Soudek, Petr [Department of Plant Tissue Cultures, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-166 10 Prague 6 (Czech Republic); Valenova, Sarka [Department of Plant Tissue Cultures, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-166 10 Prague 6 (Czech Republic); Vavrikova, Zuzana [Department of Plant Tissue Cultures, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-166 10 Prague 6 (Czech Republic); Vanek, Tomas [Department of Plant Tissue Cultures, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-166 10 Prague 6 (Czech Republic)]. E-mail: vanek@uochb.cas.cz

    2006-07-01

    The {sup 9}Sr and {sup 137}Cs uptake by the plant Helianthus annuus L. was studied during cultivation in a hydroponic medium. The accumulation of radioactivity in plants was measured after 2, 4, 8, 16 and 32 days of cultivation. About 12% of {sup 137}Cs and 20% of {sup 9}Sr accumulated during the experiments. We did not find any differences between the uptake of radioactive and stable caesium and strontium isotopes. Radioactivity distribution within the plant was determined by autoradiography. {sup 137}Cs was present mainly in nodal segments, leaf veins and young leaves. High activity of {sup 9}Sr was localized in leaf veins, stem, central root and stomata. The influence of stable elements or analogues on the transfer behaviour was investigated. The percentage of non-active caesium and strontium concentration in plants decreased with the increasing initial concentration of Cs or Sr in the medium. The percentage of {sup 9}Sr activity in plants decreased with increasing initial activity of the nuclide in the medium, but the activity of {sup 137}Cs in plants increased. The influence of K{sup +} and NH{sub 4} {sup +} on the uptake of {sup 137}Cs and the influence of Ca{sup 2+} on the uptake of {sup 9}Sr was tested. The highest accumulation of {sup 137}Cs (24-27% of the initial activity of {sup 137}Cs) was found in the presence of 10 mM potassium and 12 mM ammonium ions. Accumulation of about 22% of initial activity of {sup 9}Sr was determined in plants grown on the medium with 8 mM calcium ions.

  18. Distribution of Natural (U-238, Th-232, Ra-226) and Technogenic (Sr-90, Cs-137) Radionuclides in Soil-Plants Complex Near Issyk-Kul Lake, Kyrgyzstan

    Science.gov (United States)

    Jovanovic, L.; Kaldybaev, B.; Djenbaev, B.; Tilenbaev, A.

    2012-04-01

    Researches on radionuclides distribution in the soil-plants complex provide essential information in understanding human exposure to natural and technogenic sources of radiation. It is necessary in establishing regulation relating to radiation protection. The aim of this study was the radiochemical analysis of the content natural radionuclides 238U, 232Th,226Ra and technogenic radionuclides content (90Sr, 137Cs) in soils near Issyk-Kul lake (Kyrgyzstan). Results of radiochemical analyses have shown, that the concentrations of thorium-232 are fluctuating in the limits (11.7-84.1)-10-4% in the soils. The greatest concentration of thorium-232 has been found in the light chestnut soils. The content of uranium-238 in the soils near Issyk-Kul lake is fluctuating from 2.8 up to 12.7-10-4%. Radium-226 has more migration ability in comparison with other heavy natural radionuclides. According to our research the concentrations of radium-226 are fluctuating in the limits (9.4-43.0)-10-11%. The greatest concentration of radium-226 (43,0±2,8)-10-11% has been determined in the light chestnut soil. In connection with global migration of contaminating substances, including radioactive, the special attention is given long-lived radionuclides strontium-90 and caesium-137 in food-chains, and agroecosystems. Results of radiochemical analyses have shown, that specific activity of strontium-90 is fluctuating in the range of 2.9 up to 11.1 Bq/kg, and caesium-137 from 3.7 up to 14,3 Bq/kg in the soil of agroecosystems in the region of Issyk-Kul. In soil samples down to 1 meter we have observed vertical migration of these radionuclides, they were found to accumulate on the surface of soil horizon (0-5 cm) and their specific activity sharply decreases with depth. In addition in high-mountain pastures characterized by horizontal migration of cattle in profiles of soil, it was discovered that specific activity of radionuclides are lower on the slope than at the foot of the mountain. The

  19. Transfer parameter values in temperate forest ecosystems: a review.

    Science.gov (United States)

    Calmon, Philippe; Thiry, Yves; Zibold, Gregor; Rantavaara, Aino; Fesenko, Sergei

    2009-09-01

    Compared to agricultural lands, forests are complex ecosystems as they can involve diverse plant species associations, several vegetative strata (overstorey, shrubs, herbaceous and other annual plant layer) and multi-layered soil profiles (forest floor, hemi-organic and mineral layers). A high degree of variability is thus generally observed in radionuclide transfers and redistribution patterns in contaminated forests. In the long term, the soil compartment represents the major reservoir of radionuclides which can give rise to long-term plant and hence food contamination. For practical reasons, the contamination of various specific forest products has commonly been quantified using the aggregated transfer factor (T(ag) in m(2)kg(-1)) which integrates various environmental parameters including soil and plant type, root distribution as well as nature and vertical distribution of the deposits. Long lasting availability of some radionuclides was shown to be the source of much higher transfer in forest ecosystems than in agricultural lands. This study aimed at reviewing the most relevant quantitative information on radionuclide transfers to forest biota including trees, understorey vegetation, mushrooms, berries and game animals. For both radiocaesium and radiostrontium in trees, the order of magnitude of mean T(ag) values was 10(-3)m(2)kg(-1) (dry weight). Tree foliage was usually 2-12 times more contaminated than trunk wood. Maximum contamination of tree components with radiocaesium was associated with (semi-)hydromorphic areas with thick humus layers. The transfer of radionuclides to mushrooms and berries is high, in comparison with foodstuffs grown in agricultural systems. Concerning caesium uptake by mushrooms, the transfer is characterized by a very large variability of T(ag), from 10(-3) to 10(1)m(2)kg(-1) (dry weight). For berries, typical values are around 0.01-0.1 m(2)kg(-1) (dry weight). Transfer of radioactive caesium to game animals and reindeer and the

  20. Quantitative assessment of radionuclide retention in the near-surface system at Forsmark. Development of a reactive transport model using Forsmark 1.2 data

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Sena, Clara; Arcos, David; Molinero, Jorge; Duro, Lara; Bruno, Jordi (Amphos XXI Consulting S.L., Barcelona (Spain))

    2007-12-15

    been selected for quantitative modelling based on the availability of data and parameters. Two distinct geological and hydrogeological domains have been considered: (1) the till system and (2) the clay system. The first case simulates the intrusion of a radionuclide-bearing fluid from granite bedrock into a relatively dynamic till aquifer. In the second case, the radionuclide bearing fluid interacts with a low permeability, reducing clay layer that is present at the bottom of a discharge zone (such as a lake or the Baltic Sea, for instance), overlying the till deposit. Groundwater flow and transport modelling results highlight the different behaviour of the two simulated systems. The till system constitutes a dynamic aquifer, which reaches the transport steady-state in less than 8 years. On the other hand, the clay system constitutes a relatively low permeability aquitard in which the transport steady state needs hundreds of years to be reached. Reactive transport results indicate that caesium is very strongly retained in the FES of illite in both till and clay systems. Most of the caesium mass entering the system from the deep source is effectively retained in the very close vicinity of the source, independently of the hydrogeological conditions. In the case of uranium, the most effective processes for retention are very different depending on the two considered hydrogeological systems. In the till aquifer, the dissolved uranium is mainly adsorbed onto the charged surfaces of ferrihydrite. It is seen that this dynamic aquifer system still exhibits a uranium retention efficiency of about 50% even after about 100 years of simulation time. On the other hand, the simulated clay system is much more efficient than the till aquifer for uranium retention due to the precipitation of amorphous uranium (IV) oxides. Uranium retention efficiencies higher than 95% are computed for the clay system, even after more than 400 years. As in the case of caesium, most of the uranium mass