Ambient krypton-85 air sampling at Hanford

International Nuclear Information System (INIS)

Trevathan, M.S.; Price, K.R.

1984-10-01

In the fall of 1982, the Environmental Evaluations Section of Pacific Northwest Laboratory (PNL) initiated a network of continuous krypton-85 air samplers located on and around the Hanford Site. This effort was in response to the resumption of operations at a nuclear fuel reprocessing plant located onsite where krypton-85 was to be released during fuel dissolution. Preoperational data were collected using noble gas samplers designed by the Environmental Protection Agency-Las Vegas (EPA-LV). The samplers functioned erratically resulting in excessive maintenance costs and prompted a search for a new sampling system. State of the art krypton-85 sampling methods were reviewed and found to be too costly, too complex and inappropriate for field application, so a simple bag collection system was designed and field tested. The system is composed of a reinforced, heavy plastic bag, connected to a variable flow pump and housed in a weatherproof enclosure. At the end of the four week sampling period the air in the bag is transferred by a compressor into a pressure tank for easy transport to the laboratory for analysis. After several months of operation, the air sampling system has proven its reliability and sensitivity to ambient levels of krypton-85. 3 references, 3 figures, 1 table

Atmospheric krypton-85 during 1962 and 1963

Energy Technology Data Exchange (ETDEWEB)

Ehhalt, D.; Muennich, K. O.; Roether, W.; Schoelch, J.; Stich, W.

1963-11-15

The krypton-85 found in the atmosphere presumably originates from two different sources, namely fission bomb tests and processing of burned-out fuel elements from nuclear reactors. This paper discusses the impact of the sources of krypton in the atmosphere in greater detail.

Measurement of krypton-85 in the atmosphere with a portable apparatus

International Nuclear Information System (INIS)

Okai, T.

1984-01-01

A portable apparatus was developed for the rapid collection, separation and counting of krypton-85 in environmental air samples. The apparatus consists of a molecular sieve trap for the elimination of H 2 O and CO 2 , a charcoal trap for the collection of krypton, a chromatographic column for the isolation of krypton in the air sample and a vial for the disolution of krypton in the scintillation solution. With this apparatus, krypton can be collected from half a cubic meter of air with 94% recovery in about 3 hrs. The measurements of krypton-85 were done several time in Fukuoka area from Jan. 30 to Dec. 9, 1981. The krypton-85 concentration was found to be approximately 21 pCi/m 3 air. The results were compared with those obtained by foreign investigators. (author)

Environmental behaviour and dosimetry of Krypton-85

International Nuclear Information System (INIS)

Patek, P.

1980-12-01

Although 85 Kr has only small influence on the total radiation burden to man, monitoring and safety considerations have to be done, especially regarding the operation of fuel reprocessing plants. The natural, military and civilian sources of 85 Kr are discussed and a survey is given on the possibilities of Krypton removal from off-gas streams. Regarding the environmental behaviour of the released Krypton-amounts it was shown, that only the atmospheric dispersion is of influence to the succeeding irradiation of the population. Krypton is transferred to man only by inhalation and remains with different halflives in the human body. The highest absorbed dose is caused by beta-rays to the skin and in the airways of the lungs. While the highest dose equivalent rates to the most exposed individuals are reached by local sources from fuel reprocessing plants, the highest collective effective dose equivalent commitment is reached for global dispersed 85 Kr. (author)

Climate aspects of radioactive trace gases, especially krypton-85

International Nuclear Information System (INIS)

Kollert, R.; Butzin, M.

1990-01-01

The amount of krypton 85 currently present in the atmosphere is 3.300 Peta Bq. This atmospheric krypton contamination stems from atom bomb tests of the past and from nuclear power plants as well as spent fuel reprocessing plants. The paper investigates the air-electric and air-chemical impact of Kr-85 on the atmosphere and makes a forecast of the future Kr-85 contamination. (DG) [de

Monitoring of air pollutants and greenhouse gases. Monitoring Krypton-85

International Nuclear Information System (INIS)

Novitchkov, V.

1996-01-01

Krypton-85 is an anthropogenic radioactive noble gas, a gaseous fission product which builds up in the atmosphere. The World Meteorological Organization (WMO) Global Atmospheric Watch (GAW) integrates many monitoring and research activities involving the measurements of atmospheric composition. Kr-85 represents one of the gases recommended by the WMO for monitoring. The collaborative program of the Moscow State Engineering Physics Institute (MEPI) and the US Air Resources Laboratory (ARL) NOAA activities is aimed at determining the possible future consequences of Krypton-85 content (trend) increasing in the earth's atmosphere. The research is conducted at the MEPI to study the character of KR-85 release into the atmosphere and its distribution in the atmosphere, to determine Kr-85 possible sources. If only the question of the direct impact of Kr-85 on climate would be considered, only the order of magnitude of the atmospheric concentration would be of interest. In this case almost any available detection method and a precision as low as some 10% would be acceptable. If however, Kr-85 is to be applied as a tracer for the improvement of our present knowledge of local, regional and global transport and mixing processes and the validation of global-scale transport and mixing models, a much higher precision is required (order of +1%). This high standard cannot be met without a permanent quality assurance programmer. It is within the framework of the WMO that MEPI and the Air Resources Laboratory NOAA USA proposes collaboration of Kr-85 scientific findings. The project MEPI open-quotes Monitoring Krypton-85close quotes is being financed through the International Science and Technology Center

A review of ''The potential effects of release of krypton-85''

International Nuclear Information System (INIS)

Saunders, C.P.R.

1993-06-01

A Report into the potential effects of the release of Krypton-85 from the Thermal Oxide Reprocessing Plant (THORP) at Sellafield, was commissioned by British Nuclear Fuels Ltd. The report dealt with the atmospheric impact of the release of Krypton-85 and considered specifically the areas of atmospheric electricity, ionisation, aerosols and conductivity, in terms of the releases of Krypton-85 from THORP. This present review has three objectives: to consider the atmospheric effects of the proposed discharges from THORP, to comment upon the magnitude of the postulated effects from Krypton-85 discharges compared with those from other sources of radioactivity in the atmosphere, and, to comment on the conclusions drawn by the authors of the report. This review was conducted under the aegis of the United Kingdom Inspectorate of Pollution. (author)

Radioactivity 85Kr in krypton enriched with light isotope

International Nuclear Information System (INIS)

Kuz'minov, V.V.; Novikov, V.M.; Pomanskij, A.A.

1992-01-01

85 Kr content in krypton enriched with 78 Kr is measured within the frames of experiment for search of binary position decay and conversion of atomic electron into 78 Kr. Voluminous activity in krypton enriched up to 98% 78 Kr equal to 0.206 -0.004 +0.001 Bq/L is obtained which is by 4000 less as compared to natural krypton. 7 refs.; 1 fig.; 1 tab

Present and future potential of krypton-85 for the detection of clandestine reprocessing plants for treaty verification.

Science.gov (United States)

Schoeppner, Michael; Glaser, Alexander

2016-10-01

Burnup calculations are applied to determine the amount of krypton-85 that is produced during the irradiation of nuclear fuel. Since krypton-85 is most likely released into the atmosphere during reprocessing to separate plutonium, atmospheric transport modeling is used to calculate the worldwide distribution of krypton-85 concentrations stemming from emissions from declared reprocessing plants. The results are the basis for scenarios in which emissions from clandestine reprocessing facilities have to be detected against various background levels. It is concluded that today's background imposes heavily on the ability to detect small and medium plutonium separation rates; only high separation rates of 1 SQ per week and higher have a chance to be detected with feasible outlay. A fixed network of monitoring stations seems too costly; instead the high number of samples that are required rather calls for mobile sampling procedures, where air samples are collected at random locations over the world and are analyzed in regional laboratories for their krypton-85 concentration. Further, it is argued that krypton-85 emissions from declared reprocessing activities have to be significantly lowered to enable a worldwide verification of the absence of even smaller clandestine reprocessing. For each scenario the number of samples that have to be taken for probable detection is calculated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of control technology on the projected krypton-85 environmental inventory

International Nuclear Information System (INIS)

Oscarson, E.E.

1973-01-01

Growth projections for the USA nuclear power industry may be used to make projections of future radioactive material inventories available for potential release to the environment. Since krypton-85 is produced in reactors, the potential routes of release to the environment are at the reactors or the fuel reprocessing plants. The present generation of reactors and fuel reprocessing plants do not use any systems to limit the release of krypton-85 into the biosphere. Clean-up systems are currently being designed and could be introduced when necessary. The cumulative inventory of krypton-85 in the environment is dependent upon the time of introduction of these clean-up systems and their efficiencies, in addition to the total quantity produced. Annual and cumulative inventories of krypton-85 are projected to increase dramatically over the next 50 years. If controls are assumed to be initiated at various years, a series of graphs of different cumulative environmental inventories and the associated doses and health effects are drawn. Varying the year of introduction and the efficiency of these systems allows one to speculate as to the optimum time for control implementation

Krypton-85 enrichment by adsorption-desorption process

International Nuclear Information System (INIS)

Khan, A.A.; Deshingkar, D.S.; Ramarathinam, K.

1975-01-01

The use of activated charcoal columns in conjunction with cryogenic distillation system for concentration of krypton-85 in fuel reprocessing process off-gas stream is reported. Dynamic adsorption of krypton on activated charcoals and its subsequent desorption by applying vacuum were studied. The possible reduction in the quantity of carrier gas to be liquified in the cryogenic system by utilising this process has been discussed on the basis of results of laboratory evaluations. The possibility of elimination of air and oxygen to avoid explosion hazards associated with radiolytic formation and concentration of ozone has also been considered. (author)

Preliminary safety evaluation of a commercial-scale krypton-85 encapsulation facility

International Nuclear Information System (INIS)

Christensen, A.B.; Tanner, J.E.; Knecht, D.A.

1980-09-01

This report demonstrates that a commercial-scale facility for encapsulating krypton-85 in zeolite-5A or glass at a 2000 MTHM per year nuclear fuel reprocessing plant can be designed to contain fragments and the 340 to 850 kCi krypton-85 inventory from an assumed catastrophic failure of the high pressure vessel. The vessel failure was assumed as a worst case and was not based on a detailed design evaluation or operating experience. The process design is based on existing commercial hot isostatic pressing technology operated at up to 40 times the scale required for krypton encapsulation. From the calculated process gas inventory in the pressure vessel and vessel design, the explosive energy of 8.4 kg TNT and vessel plug and fragment velocities were calculated. The facility Containment Cell housing the high pressure vessel was designed to contain the gases, fragments, and the shock wave energy calculated for vessel failure. The Access Cell located directly above the Containment Cell was designed to be a tertiary confinement of krypton-85, should the access hatch be breached

Immobilization of krypton-85 in zeolite 5A

International Nuclear Information System (INIS)

Christensen, A.B.; Del Debbio, J.A.; Knecht, D.A.; Tanner, J.E.; Cossel, S.C.

1983-01-01

This paper describes the technical feasibility and presents a summary of a preconceptual design and cost estimate for a process to immobilize krypton-85 by sintering in zeolite 5A at 700 0 C and 100 MPa for 2 to 4 h. Krypton loading of 30 to 60 m 3 at STP per m 3 solid can be achieved. The initial water concentration in zeolite 5A has a catalytic effect on the sintering rate and must be kept at about 1 wt% by heating prior to the encapsulation run. High initial water loadings and/or encapsulation times longer than 4 h must be avoided because the sintered zeolite 5A recrystallizes to an anorthite-type feldspar and releases the trapped krypton. Data are presented to show how the process conditions affect krypton encapsulation in zeolie 5A and how to assure the quality of the product. By adding a powdered glass frit to the commercial zeolite 5A 2 mm beads, a solid mass is formed during encapsulation, which can be further compacted using standard hot isotatic pressing techniques at 33 MPa and 600 0 C to form a fused glassy matrix enclosing the amorphous zeolite. A process for encapsulating the annual krypton-85 production at a commercial 2000 metric ton of heavy metal spent fuel reprocessing plant is developed. A hot isostatic press (HIP) with an isolated work zone of 8 or 16 L capacity is required to operate for 600 or 300 cycles per year, respectively. Existing HIP technology uses work zones from 1 to 3500 L capacity at similar production rates. A combined encapsulation/compaction cycle is proposed as an option to most effectively immobilize the krypton and the zeolite. A preconceptual design and cost estimate is given for a commercial-scale Kr encapsulation facility. The facility is designed to withstand a worst case rupture of the HIP. The maximum lease is estimated to result in an off-site dose well below accident protective action guidance levels

Krypton-85 storage in sputter-deposited amorphous metals

International Nuclear Information System (INIS)

Tingey, G.L.; McClanahan, E.D.; Lytle, J.M.; Gordon, N.R.; Knoll, R.W.

1982-06-01

After comparing options for storing radioactive krypton gas, the United States Department of Energy selected ion implantation of the gas into a sputter-deposited metal matrix as the reference process. This technique is being developed with pilot-scale testing and further characterization of the deposited product. The process involves implanting krypton atoms into a growing deposit during the sputtering process. An amorphous metal deposit of nominal composition Ni 0 81 La 0 09 Kr 0 10 has been selected for further studies because of the high krypton loading, high sputtering yield, relatively low cost of the metallic components, resistance to corrosion, and stability of the product. The krypton release from this amorphous metal is described as an activated diffusion process which increases linearly with the square root of time. Studies of krypton release rate as a function of temperature were completed and an activation energy for the diffusion of 70 kcal/mole obtained. From these data, we estimated that the krypton release during the first ten years would be 0.5% for a maximum temperature of 350 0 C. The actual release of the krypton during storage was projected to be lower by a factor of 10 7 with the maximum temperature only 220 0 C. Thermal analysis studies show two energy releases occurring with krypton-containing alloys: one associated with recrystallization of the amorphous alloy and a second associated with krypton release. The total energy release between 100 and 800 0 C was less than 50 cal/g. Estimates are given for the cost of operation of the ion implantation process for solidification of the krypton-85 from a 2000-tonne heavy metal/year reprocessing plant. The present value costs, in 1981 dollars including capital and operating costs and assuming a 30-year life, are about $26M for the lifetime of the plant. Annual energy consumption of the process was estimated to be 3.9 M kWh/year

Preliminary safety evaluation of a commercial-scale krypton-85 encapsulation facility

International Nuclear Information System (INIS)

Christensen, A.B.; Tanner, J.E.; Knecht, D.A.

1980-01-01

This paper demonstrates that a commercial-scale facility for encapsulating krypton-85 in zeolite-5A or glass at a 2000 MTHM per year nuclear fuel reprocessing plant can be designed to contain fragments and the 340 to 850 kCi krypton-85 inventory from an assumed catastrophic failure of the high pressure vessel. The vessel failure was assumed as a worst case and was not based on a detailed design evaluation or operating experience. The process design is based on existing commercial hot isostatic pressing technology operated at up to 40 times the scale required for krypton encapsulation. From the calculated process gas inventory in the pressure vessel and vessel design, the maximum explosive energy of 8.4 kg TNT and resulting vessel plug and fragment velocities were calculated. The facility Containment Cell housing the high pressure vessel was designed to contain the gases, fragments, and the shock wave energy calculated for a hypothetical vessel failure. The Access Cell located directly above the Containment Cell was designed to be a tertiary confinement of krypton-85, should the access hatch be breached. 3 figures, 2 tables

Immobilization of krypton-85 in zeolite 5A and porous glass

International Nuclear Information System (INIS)

Christensen, A.B.; DelDebbio, J.A.; Knecht, D.A.; Tanner, J.E.; Cossel, S.C.

1981-12-01

This report demonstrates the technical and economic feasibility for immobilizing krypton-85 by high pressure/high temperature encapsulation in zeolite 5A or thirsty Vyco porous glass. Data are presented to show how process conditions affect the encapsulation and how to compact the zeolite beads with glass frit or other additives to form a fused mass with low dispersibility potential. Krypton specific loadings of 30 and 50 m 3 STP gas per m 3 solid are readily achieved at 100 MPa in porous glass at 900 0 C and zeolite 5A at 700 0 C. Krypton is encapsulated by a sintering process where the porous glass and zeolite 5A voids are sealed. With zeolite 5A, the initial water concentration has a catalytic effect on the sintering, resulting in a transition from crystalline zeolite 5A to an amorphous aluminosilicate. Krypton leakage experiments are used to predict leakage rates from glass or zeolite of less than 0.03% and 0.3% for 10-y storage at 300 and 400 0 C, respectively. Heating the loaded zeolite at 600 to 700 0 C for 4 h removes 0.1% of the total krypton which is loosely held and reduces the subsequent leakage rates at 300 to 400 0 C. Zeolite 5A is chosen as the preferred material to immobilize krypton-85. A preconceptual design and cost estimate is given for a facility to encapsulate 110% of the krypton production of a 2000 metric ton of heavy metal per year reprocessing plant, or 230 m 3 of gas containing 19 MCi of krypton-85. A hot isostatic press (HIP) with an isolated work zone of 8 or 16 L capacity is required to operate for 600 or 300 cycles per year, respectively. Existing HIP technology uses work zones from 1 to 3500 L capacity at similar production rates. A preliminary safety evaluation shows that an incredible worst case accident could be contained and the maximum off-site dose would be well below accident protective action guidance levels

10 CFR 32.22 - Self-luminous products containing tritium, krypton-85 or promethium-147: Requirements for license...

Science.gov (United States)

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Self-luminous products containing tritium, krypton-85 or... containing tritium, krypton-85 or promethium-147: Requirements for license to manufacture, process, produce... self-luminous products containing tritium, krypton-85, or promethium-147, or to initially transfer such...

Environmental consequences of atmosphereic krypton-85. Final report, January 1, 1977-September 30, 1979

International Nuclear Information System (INIS)

Boeck, W.L.

1979-01-01

Krypton-85 is a radioactive inert gas produced during normal operations of the nuclear fuel cycle. The quantities of krypton-85, that will be produced in the next century, are sufficient, if released, to alter the electrical state of the atmosphere. The principal hypothesis is that an anthropogenic alteration of the electric state of the atmosphere could alter other meterological phenomena and lead to significant environmental impacts. The goal of this project was to explore some areas of basic science related to the evaluation of that hypothesis. The approach was primarily theoretical. The following topics were addressed: a first approximation model to estimate the effects of krypton-85 on the electrical state of the atmosphere; an analysis of the pathways between krypton-85 production and the atmosphere; an analytical model for fair weather atmospheric electricity; and a dipole model for atmospheric electricity. The results will provide a framework on which detailed models can be built. The results should provide better understanding of some topics in atmospheric electricity

Study on the possibility of sea-disposal of krypton-85

International Nuclear Information System (INIS)

Dalen, A. van; Vons, L.H.; Verkerk, B.

1980-01-01

Results of a feasibility study, performed under a contract with the Commission of the European Communities, regarding technical and radiological aspects of sea-disposal of all krypton-85 retained in a large fuel reprocessing facility, are presented. The design of a double-walled, essentially spherical container is described that provides both double containment of the compressed gas and permanent 'disposable' radiation shielding. Three sizes have been studied, i.e. with internal volumes of 0.01, 0.05 and 0.1 m 3 , each designed to hold 0.1 m 3 (STP) of krypton, and each containing approximately 400 TBq of 85 Kr per 0.001 m 3 sphere volume. This results in an internal heat production of 17.5 kW/m 3 . Calculations of temperatures and stresses that would result from the conditions of the required fire test for B(U) transport packages showed that the design would allow the containers to pass this test. Radiological consequences have been considered for disposal of petabecquerel amounts of 85 Kr as a function of undamaged container lifetime on the sea bed. Finally, an indication is given of the necessary amendments to the London Convention in order to allow sea-disposal of these large amounts of radioactive krypton. (author)

Simulations of Atmospheric Krypton-85 to Assess the Detectability of Clandestine Nuclear Reprocessing

International Nuclear Information System (INIS)

Ross, O.; Ahlswede, J.; Annewandter, R.; Kalinowski, M.B.; Rast, S.; Schluenzen, K.H.

2010-01-01

The results of this study were achieved in the project 'Simulation of Atmospheric Noble Gas Concentrations to Assess Sampling Procedures for the Detection of Clandestine Nuclear Reprocessing' (IAEA GER 1643) in the joint programme of IAEA and Federal Government of Germany. In the first year of the project the detectability of additional krypton-85 sources was investigated using atmospheric transport modelling. Krypton-85 is released into the air during reprocessing of spent nuclear fuel rods. Therefore the krypton-85 signature can possibly be used for the detection of undeclared plutonium separation. First, the global krypton-85 background produced by known reprocessing facilities from 1971 until 2006 was simulated with the atmospheric general circulation model ECHAM5 using annual emission data. The model results were evaluated by extensive comparison with measurements performed by the German Federal Office for Radiation Protection. Of particular interest for an assessment of the detectability of unknown sources is the background variability. The variability of concentrations is very high over central Europe, where the large reprocessing plants La Hague and Sellafield are located, and it is very low on the Southern Hemisphere, where no nuclear reprocessing takes place. The analysis of concentration time series on various time scales allows partly a distinction between fluctuations caused by the variability of the sources from variations due to atmospheric dynamics. Furthermore the detection sensitivity to a set of arbitrarily specified source locations is analysed with a Lagrangian particle dispersion model. This, in combination with the location specific background variability, is giving first benchmarks on the capability of using krypton-85 for IAEA Safeguards based on the Additional Protocols foreseeing environmental sampling. (author)

Separation, storage, and disposal of krypton-85: status and projects

Energy Technology Data Exchange (ETDEWEB)

Laser, M.

1976-09-15

Despite the relatively small impact of ⁸⁵Kr to man the separation of fission krypton from the off-gas of fuel reprocessing plants must be taken into account. Combined with other advantages also in power reactor stations the retention of ⁸⁵Kr seems to be attractive. Cryogenic processes are favored worldwide, because the technology has been well proven during several decades in air liquefaction and separation plants. Relatively small modifications must be made to adjust these processes to fission gas separation plants. Some fundamental data however are necessary for the design of a plant. Besides cryogenic processes a liquid adsorption for reprocessing off-gases and charcoal adsorption processes for reactor off-gas are under discussion. The retained krypton can be stored under air or water cooling in usual pressurized steel cylinders. However, legal problems may arise. The steel cylinders can be stored in engineered storage facilities for an intermediate period or finally. In Europe, however, the final storage will be questionable. Therefore, the dumping of ⁸⁵Kr into the deep sea has been proposed. For this reason a revision of the London Convention is necessary, because the dumping of ⁸⁵/Kr has not been specified. The IAEA as competent authority is asked to define the conditions for dumping. Injection of krypton containing gases into porous geologic strata may also be possible, if a very small release can be guaranteed.

Application of krypton-85 in groundwater dating

International Nuclear Information System (INIS)

Rozanski, K.

1979-01-01

The method for determination 85 Kr activity in groundwater and its application in isotope hydrology is presented. Various aspects of 85 Kr presence in the earth's ecosphere are discussed in the first part of the paper. The method for 85 Kr activity measurement in groundwater is presented in the second part of the paper. Analytical procedure consists of the following steps: extraction of the gases dissolved in water sample, separation of the Ar+Kr mixture from the gases, 85 Kr activity measurement in miniature proportional counter, mass spectrometry determination of the krypton gas volume in the proportional counter. About 7 days is necessary for complete analysis of one sample - the error of analysis not exceeds 10 per cent. The results of 85 Kr activity measurements (together with tritium and carbon 14 C determinations) in 14 different water samples allowed to verify usefulness of 85 Kr dating of young water. (author)

Krypton-85 and other airborne radioactivity measurements throughout Ireland

International Nuclear Information System (INIS)

Smith, K.J.; Murray, M.; Wong, J.; Sequeira, S.; Long, S.C.; Rafferty, B.

2004-01-01

In compliance with articles 35 and 36 of the EURATOM Treaty, the Radiological Protection Institute of Ireland (RPII) undertakes a comprehensive programme of radioactivity monitoring in the Irish terrestrial environment. Radioactivity is present in the terrestrial environment due to natural processes, the testing of nuclear weapons in the atmosphere, accidents such as the Chernobyl accident and the routine discharge of radionuclides from nuclear installations. The RPII monitors airborne radioactivity concentrations at ten stations throughout Ireland, of which, nine are equipped with low volume particulate samplers and one, in Dublin, with a high volume particulate sampler. The low volume particulate samples are assessed for total beta activity and high volume samples for gamma emitting radionuclides such as caesium-137 and beryllium-7. In addition, air sampled at the RPII laboratory in Dublin, is monitored for krypton-85, a radioactive noble gas, released into the environment primarily as a result of the reprocessing of nuclear fuel at installations such as Sellafield in the UK and La Hague in France. Since the inception of the krypton measurements in 1993 a trend of increasing atmospheric concentrations has been observed. The results of the krypton-85 monitoring, as well as the airborne radioactivity concentration measurements, will be presented and discussed in this paper. (author)

Krypton-85 Monitoring at BfS in Germany and Technical Solutions for Safeguards

International Nuclear Information System (INIS)

Schlosser, C.; Klingberg, F.

2015-01-01

The radioactive noble gas isotope krypton-85 with a half-life of 10.76 years is produced by nuclear fission. The main source of krypton-85 in the atmosphere are releases from reprocessing plants for nuclear fuel in the Northern Hemisphere. This volatile isotope is not retained in such plants and thus a very good indicator for the processing of irradiated nuclear fuel. This includes reprocessing for military purposes. Additionally, Kr-85 could be used as tracer for the validation of Atmospheric Transport Models. The German Federal Office for Radiation Protection (BfS) operates a noble gas laboratory and a global network which continuously monitors the krypton-85 activity concentrations in ground level air since the 1970s. The atmospheric activity concentration has continuously been increasing since the installation of reprocessing plants for nuclear fuels in the early 1950s until 2003. In the first decades it came mostly from military applications and later from civil reprocessing. Since 2003 the atmospheric krypton-85 background level in the Northern Hemisphere is nearly constant with a value of around 1.5 Bq/m 3 in Central Europe. The baseline is superimposed by spikes as a result from discharges of two European reprocessing plants of nuclear fuel, Sellafield and La Hague. The laboratory of the BfS and the techniques used will be presented. Long time series will be discussed and the use of ATM for source location demonstrated. (author)

The Study of Reducing Krypton-85 Activity in Metal Halide Lamp%降低金卤灯内氪-85活度的研究

Institute of Scientific and Technical Information of China (English)

叶碧君

2012-01-01

通过测试及分析不同氪-85活度填充气体的同规格金卤灯的各项性能参数,研究了在确保金卤灯各项性能的前提下,降低金卤灯中氪-85活度的可行性及金卤灯中氪-85存在的必要性,可以为今后确定金卤灯中需添加的最低氪-85活度提供参考。%By analyzing the parameters of metal halide lamps which are filled with gas with different activity of krypton-85, the paper studies the feasibility of reducing krypton-85 activity in metal halide lamp while ensuring the lamp performance, and proves the necessity of its existence of krypton-85 in metal halide lamp. it can provide us a reference to determine the minimum krypton-85 activity to he added in metal halide lamps.

Variability of atmospheric krypton-85 activity concentrations observed close to the ITCZ in the southern hemisphere.

Science.gov (United States)

Bollhöfer, A; Schlosser, C; Ross, J O; Sartorius, H; Schmid, S

2014-01-01

Krypton-85 activity concentrations in surface air have been measured at Darwin, which is located in northern Australia and is influenced by seasonal monsoonal activity. Measurements between August 2007 and May 2010 covered three wet seasons. The mean activity concentration of krypton-85 measured during this period was 1.31±0.02Bqm(-3). A linear model fitted to the average monthly data, using month and monsoon as predictors, shows that krypton-85 activity concentration measured during the sampling period has declined by 0.01Bqm(-3) per year. Although there is no statistically significant difference in mean activity concentration of krypton-85 between wet and dry season, the model implies that activity concentration is higher by about 0.015Bqm(-3) during months influenced by the monsoon when a north westerly flow prevails. Backward dispersion runs using the Lagrangian particle dispersion model Hysplit4 highlight possible source regions during an active monsoon located deep in the northern hemisphere, and include reprocessing facilities in Japan and India. However, the contribution of these facilities to krypton-85 activity concentrations in Darwin would be less than 0.003Bqm(-3). Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

California GAMA Special Study. Development of a Capability for the Analysis of Krypton-85 in Groundwater Samples

Energy Technology Data Exchange (ETDEWEB)

Visser, Ate [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bibby, Richard K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Moran, Jean E. [California State Univ. (CalState), Long Beach, CA (United States); Singleton, Michael J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Esser, Bradley K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-06-01

A capability for the analysis of krypton-85 (⁸⁵Kr) in groundwater samples was developed at LLNL. Samples are collected by extracting gas from 2000-4000 L of groundwater at the well, yielding approximately 0.2 cm³ STP krypton. Sample collection takes 1 to 4 hours. Krypton is purified in the laboratory using a combination of molecular sieve and activated charcoal traps, and transferred to a liquid scintillation vial. The ⁸⁵Kr activity is measured by liquid scintillation on a Quantulus 1220 liquid scintillation counter from PerkinElmer. The detection limit for a typical 0.2 cm³Kr sample size is 11% of the present day activity in air, corresponding to the decay corrected activity in air in 1987. The typical measurement uncertainty is below 10% for recently recharged samples. Six groundwater samples were collected, purified and counted. ⁸⁵Kr was not detected in any of the samples counted at LLNL. ⁸⁵Kr was detected by the low level counting laboratory of Bern University in all samples between 1.5 and 6.6 decays per minute per cm³ krypton, corresponding to decay corrected activities in air between 1971 and 1985. The new capability is an excellent complement to tritium-helium, expanding the existing suite of age dating tools available to the GAMA program (³⁵S, ³H/³He, ¹⁴C and radiogenic helium). ⁸⁵Kr can replace ³H/³He in settings where ³H/³He ages are impossible to determine (for example where terrigenic helium overwhelms tritiogenic helium) and provides additional insight into travel time distributions in complex mixed groundwater systems.

Design for a Remote Monitoring Equipment of Krypton-85

Institute of Scientific and Technical Information of China (English)

LUXue-sheng; LIUGuo-rong; YEFeng; JINHui-min; TANGPei-jia

2003-01-01

A prototype equipment for monitoring Krypton-85 in situ is designed and set up. A series of relevant software is also developed for remote control, data acquirement and data analysis. Weight of the system is about 300 kg, which is composed of NaI(T1) detector, digi DART, Marillin measurement container and lead shield. The whole system is placed on a homemade go-cart.

Krypton-85 disposal program. Semiannual report, August 15, 1977--March 31, 1978

International Nuclear Information System (INIS)

Klett, R.D.

1979-02-01

The first 7.5 months of the Krypton-85 disposal program are summarized. Included are task definitions and initial progress in geologic disposal system studies, SURF compatibility, augmented heat dissipation, material qualification, exterior canister compatibility, ceramic liners for canisters, and geologic transport. Feasibility studies indicate that Kr-85 can be disposed of at SURF facility or in near-surface geologic repositories

Climate risks by radioactive krypton-85 from nuclear fission. Atmospheric-electrical and air-chemical effects of ionizing radiation in the atmosphere

International Nuclear Information System (INIS)

Kollert, R.

1994-01-01

The study shows that krypton-85 from nuclear fission enhances air ionization and, thus, interferes with the atmospheric-electrical system and the water balance of the earth atmosphere. This is reason for concern: There are unforeseeable effects for weather and climate if the krypton-85 content of the earth atmosphere continues to rise. There may be a krypton-specific greenhouse effect and a collapse of the natural atmospheric-electrical field. In addition, human well-being may be expected to be impaired as a result of the diminished atmospheric-electrical field. There is also the risk of radiochemical actions and effects caused-by krypton-85-containing plumes in other air-borne pollutants like the latters' transformation to aggressive oxidants. This implies radiation smog and more acid rain in the countries exposed. This study summarizes findings gained in these issues by various sciences, analyses them and elaborates hypotheses on the actions and effects of krypton-85 on the air, the atmosphere and the climate. (orig./HP) [de

Krypton-85 hydrofracture engineering feasibility and safety evaluation

Energy Technology Data Exchange (ETDEWEB)

Peretz, F.J.; Muller, M.E.; Pan, P.Y.

1981-07-01

Engineering studies have been made to determine the hazards associated with the disposal of /sup 85/Kr using the hydrofracture process. To assess the hazards, an effort has been made to identify the equipment required to entrain and dissolve the noble gas into the grout stream at hydrofracture pressure (up to 350 bar). Off-the-shelf or slightly modified equipment has been identified for safe and effective compression and gas-grout mixing. Each monthly injection disposes of 1.6 x 10/sup 6/ Ci of /sup 85/Kr. By connecting only one gas cylinder to the injection system at a time, the maximum amount of krypton likely to be released as a result of equipment failure is limited to 128,000 Ci. An evaluation by Los Alamos Technical Associates shows that releasing this amount of gas in less than one hour under worst-case meteorological conditions through a 30-m stack would result in a whole-body dose of 170 millirem at a distance of 1 km from the facility. A krypton collection and recovery system can further reduce this dose to 17 millirem; increasing the distance to the site boundary to 3 km can also reduce the dose by a factor of ten. Lung and skin dose estimates are 1.6 and 120 times the whole-body dose, respectively. These are all worst-case values; releases under more typical conditions would result in a significantly lower dose. No insurmountable safety or engineering problems have been identified.

Krypton-85 hydrofracture engineering feasibility and safety evaluation

International Nuclear Information System (INIS)

Peretz, F.J.; Muller, M.E.; Pan, P.Y.

1981-07-01

Engineering studies have been made to determine the hazards associated with the disposal of 85 Kr using the hydrofracture process. To assess the hazards, an effort has been made to identify the equipment required to entrain and dissolve the noble gas into the grout stream at hydrofracture pressure (up to 350 bar). Off-the-shelf or slightly modified equipment has been identified for safe and effective compression and gas-grout mixing. Each monthly injection disposes of 1.6 x 10 6 Ci of 85 Kr. By connecting only one gas cylinder to the injection system at a time, the maximum amount of krypton likely to be released as a result of equipment failure is limited to 128,000 Ci. An evaluation by Los Alamos Technical Associates shows that releasing this amount of gas in less than one hour under worst-case meteorological conditions through a 30-m stack would result in a whole-body dose of 170 millirem at a distance of 1 km from the facility. A krypton collection and recovery system can further reduce this dose to 17 millirem; increasing the distance to the site boundary to 3 km can also reduce the dose by a factor of ten. Lung and skin dose estimates are 1.6 and 120 times the whole-body dose, respectively. These are all worst-case values; releases under more typical conditions would result in a significantly lower dose. No insurmountable safety or engineering problems have been identified

Charge state distribution of ionic kryptons after photoionization

International Nuclear Information System (INIS)

Cai Xiaohong

1992-01-01

Monochromatic X-rays from the 2.3 GeV synchrotron at University Bonn (Germany) are employed for inner shell excitation of krypton. Various ionic kryptons and a number of electrons are produced due to photoionization. In order to study the equilibrium charge state distribution of ionic kryptons, a time of flight mass spectrometer is set up and used to measure the resulting ionic charge spectra with photo energies near the L 1 - , L 2 - and L 3 - absorption edges of krypton. The energy dependence of relative probabilities is presented

A method for measurement of the krypton-85-content in the atmosphere

International Nuclear Information System (INIS)

Stockburger, H.; Sittkus, A.

1975-01-01

To measure the Kr-85 content in the atmosphere we developed a simple method. Within a time internal of five to ten days (depending on the moisture of the air) five to ten m 3 of air (NTP) are pumped through activated carbon (pressure 300 torr, temperature 77 K). When sampling time is over, the carbon is heated to 470 K. This gives a gas sample of 4 l with more than 90% of the atmospherical krypton in 3 hours. With a further step of enrichment, the volume of the sample is reduced to 100 ml. The final separation of krypton from O 2 , N 2 , CO, CO 2 and Xe is made by gaschromatography at room temperature with methane as eluent gas (duration 25 min). The Kr-fraction is transported to a proportional counter (200 ml). The overall yield is 90%. The overall error of the Kr-85-content is near 1%. Data are given for the time of 15.6.1973 to 29.12.1974. (orig.) [de

Design documentation: Krypton encapsulation preconceptual design

International Nuclear Information System (INIS)

Knecht, D.A.

1994-10-01

US EPA regulations limit the release of Krypton-85 to the environment from commercial facilities after January 1, 1983. In order to comply with these regulations, Krypton-85, which would be released during reprocessing of commercial nuclear fuel, must be collected and stored. Technology currently exists for separation of krypton from other inert gases, and for its storage as a compressed gas in steel cylinders. The requirements, which would be imposed for 100-year storage of Krypton-85, have led to development of processes for encapsulation of krypton within a stable solid matrix. The objective of this effort was to provide preconceptual engineering designs, technical evaluations, and life cycle costing data for comparison of two alternate candidate processes for encapsulation of Krypton-85. This report has been prepared by The Ralph M. Parsons Company for the US Department of Energy

Design documentation: Krypton encapsulation preconceptual design

Energy Technology Data Exchange (ETDEWEB)

Knecht, D.A. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1994-10-01

US EPA regulations limit the release of Krypton-85 to the environment from commercial facilities after January 1, 1983. In order to comply with these regulations, Krypton-85, which would be released during reprocessing of commercial nuclear fuel, must be collected and stored. Technology currently exists for separation of krypton from other inert gases, and for its storage as a compressed gas in steel cylinders. The requirements, which would be imposed for 100-year storage of Krypton-85, have led to development of processes for encapsulation of krypton within a stable solid matrix. The objective of this effort was to provide preconceptual engineering designs, technical evaluations, and life cycle costing data for comparison of two alternate candidate processes for encapsulation of Krypton-85. This report has been prepared by The Ralph M. Parsons Company for the US Department of Energy.

Encapsulation of krypton-85 in zeolite molecular sieve with a hot isostatic press

International Nuclear Information System (INIS)

Christensen, A.B.; DelDebbio, J.A.; Knecht, D.A.; Tanner, J.E.

1986-01-01

This paper describes pilot and full-scale experiments which demonstrated the feasibility of immobilizing Kr-85 in a zeolite 5A/glass mixture and compacting it before disposal. The full volume of a one-liter hot isostatic press (HIP) was used to trap argon in zeolite 5A. For radioactive krypton the HIP was modified to isolate the Kr-85 in the work zone. Details of the HIP modifications, experimental procedure, and sample analysis are reported

Technical feasibility of krypton-85 storage in sodalite

International Nuclear Information System (INIS)

Benedict, R.W.; Christensen, A.B.; Del Debbio, J.A.; Keller, J.H.; Knecht, D.A.

1979-01-01

Based on these experimental results, the process that is technically feasible for a reference 2000 metric ton of heavy metal (MTHM) per year reprocessing plant producing approx. 17 MCi or approx. 190 m 3 at STP would encapsulate krypton at approx. 20 cm 3 /g from krypton at temperatures greater than 575 0 C and pressures greater than 1600 atm with one batch a day in a 58-L high pressure vessel. Based on preliminary measurements at 500 0 C, the same process also would be feasible for a 70% krypton and 30% xenon mixture. 7 figures

Process and apparatus for separating and recovering krypton-85 from exhaust gas of nuclear reactor or the like

International Nuclear Information System (INIS)

Yusa, H.; Kamiya, K.; Murata, T.; Yamaki, H.; Hisatomi, S.

1975-01-01

An apparatus is described for separating and recovering radioactive krypton-85 contained in an exhaust gas of a nuclear reactor or the like, which comprises a plurality of adsorption beds connected in parallel with respect to a passageway for the exhaust gas, each being packed with activated carbon, wherein adsorption and desorption of krypton-85 in each of the beds are alternatively and repeatedly performed by operating valves disposed between each of the beds and means for reducing pressure in the beds to be desorbed in accordance with a predetermined time schedule. The adsorption and concentration efficiencies are markedly increased by combining the above adsorption apparatus and a distillation apparatus

Deactivation of tracer-flo equipment thru retrieval of its radioactive Krypton-85 gas

International Nuclear Information System (INIS)

Domondon, D.B.; Rara, R.B.; Borras, A.M.

1994-01-01

Tracer-flo equipment must be cleared of Krypton-85 before these can be transported. The rules and regulations on safe transport of radioactive materials require Kr-85 gas to be transported in an approved container. A new innovative technique/procedure in deactivating tracer-flo equipment i.e., without separation of the Kr-85 from the nitrogen was developed by the authors. The developed procedure was successfully applied in four tracer-flo equipment of three (3) semiconductor firms. In the process, the three firms have saved about US$ 28,000.00 (P 800,000.00) if the deactivation were undertaken by a foreign service company. The Philippine Nuclear Research Institute (PNRI) retrieved about P 382,000.00 worth of Kr-85 that could be used in industrial applications such as leak tracing of buried pipes, etc. (author). 1 ref.; 5 figs

Automated Sampling and Extraction of Krypton from Small Air Samples for Kr-85 Measurement Using Atom Trap Trace Analysis

International Nuclear Information System (INIS)

Hebel, S.; Hands, J.; Goering, F.; Kirchner, G.; Purtschert, R.

2015-01-01

Atom-Trap-Trace-Analysis (ATTA) provides the capability of measuring the Krypton-85 concentration in microlitre amounts of krypton extracted from air samples of about 1 litre. This sample size is sufficiently small to allow for a range of applications, including on-site spot sampling and continuous sampling over periods of several hours. All samples can be easily handled and transported to an off-site laboratory for ATTA measurement, or stored and analyzed on demand. Bayesian sampling methodologies can be applied by blending samples for bulk measurement and performing in-depth analysis as required. Prerequisite for measurement is the extraction of a pure krypton fraction from the sample. This paper introduces an extraction unit able to isolate the krypton in small ambient air samples with high speed, high efficiency and in a fully automated manner using a combination of cryogenic distillation and gas chromatography. Air samples are collected using an automated smart sampler developed in-house to achieve a constant sampling rate over adjustable time periods ranging from 5 minutes to 3 hours per sample. The smart sampler can be deployed in the field and operate on battery for one week to take up to 60 air samples. This high flexibility of sampling and the fast, robust sample preparation are a valuable tool for research and the application of Kr-85 measurements to novel Safeguards procedures. (author)

A survey of methods for separating and immobilizing krypton-85 arising from a nuclear fuel reprocessing plant

International Nuclear Information System (INIS)

Taylor, P.

1990-12-01

This report reviews the literature on methods to separate and immobilize krypton-85 arising from dissolution or prior treatment of nuclear fuel in a reprocessing plant. It was prepared as part of a broader review of fuel reprocessing waste management methods that might find future applications in Canada. Cryogenic distillation is the most fully demonstrated method of separation of krypton from off-gases, but it is complex. In particular, it requires pretreatment of the gas stream to eliminate several other components before the final distillation. The most highly developed alternative process is fluorocarbon adsorption, while several other processes have been investigated on a bench scale. The simplest method of storing radioactive krypton is in compressed-gas cylinders, but the risks of accidental release are increased by the corrosive nature of the decay product, rubidium. Encapsulation in either a metal matrix or a hydrothermally vitrified zeolite appears to offer the most secure immobilization of krypton. Processes for both types of material have been demonstrated inactively on a scale approaching that required for treatment of off-gases from a commercial-scale fuel reprocessing plant. Low-operating temperatures and pressures of the metal encapsulation process, compared with encapsulation in zeolites, represent a definite advantage, but electrical power requirements for the former process are relatively high. It appears that suitable technology is available for separation and immobilization of radioactive krypton, should the need arise in Canada in the future

The study of radiochemical separation methods on gaseous Fission product krypton-88

International Nuclear Information System (INIS)

Yang Zhihong; Zhang Shengdong; Yang Lei; Ding Youqian; Sun Hongqing; Ma Peng

2012-01-01

Half-life of krypton-88 is 2.84 hours, high fission yields and a relatively large gamma branching ratio is had. The gas is short-lived fission products in burnup measurements. Only New fission products can extract from extraction in gas of fissile irradiation target. But krypton-88 with krypton-85, krypton-87, xenon -135, and xenon-138 is coexisted together, thus radiochemical separation must quickly taken. selected the irradiation time is 1-2 hours and cooling time is best 2 hours for sample preparation, krypton and xenon were separated using activated carbon adsorption, the ratio of krypton and xenon were measured by gamma spectroscopy. Then according to the ratio of krypton-85 and xenon-125 count rate coefficient around separation were calculated yield of krypton and decontamination factor of xenon and the final the yield of krypton-85 is calculated. (authors)

Solubility of krypton in liquid CO2

International Nuclear Information System (INIS)

Notz, K.J.; Meservey, A.B.

1976-06-01

The solubility of krypton in liquid CO 2 was measured experimentally over essentially the entire liquid range of CO 2 , from -53 to 29 0 C. A tracer technique using 85 Kr was employed, and equilibrated gas-liquid samples were analyzed in situ with a collimated counter. Dilute concentrations of krypton were used, and the data are expressed as a distribution ratio, Y/sub Kr//X/sub Kr/, the log of which is nearly linear with respect to temperature from the lowest temperature to about 20 0 C, above which the values fall off rapidly toward a value of unity at the critical temperature. The numerical values obtained for the distribution ratio increase from 1.44 at 29 0 C to 29.4 at -53 0 C

Method for separating krypton isotopes

International Nuclear Information System (INIS)

Porter, J.T.

1980-01-01

Methods and apparatus for separating krypton isotopes utilizing low temperature selective infrared excitation of 85krypton difluoride in an isotopic compound mixture. Multiphoton ir excitation and uv excitation techniques are used, as well as cryogenic matrix isolation and inert buffer gas isolation techniques

Toxicology of Krypton-85

International Nuclear Information System (INIS)

Ballou, J.E.

1982-01-01

The purpose of this research is to obtain biological data to supplement earlier evaluations of the hazards of 85 Kr exposure. The studies include both short-term and chronic exposure of rats, dogs and sheep to determine tissue distribution and retention kinetics for metabolic modeling purposes. Dose-effect studies in rats exposed acutely as newborns or chronically for most of their life span are included to identify tissues at risk and determine tumorigenic potency

Long-term storage of recovered krypton

International Nuclear Information System (INIS)

Horii, Yuji; Yamamoto, Yoshimasa

1983-01-01

Various storage methods for krypton-85 recovered from a nuclear fuel reprocessing plant are under development in many countries. These methods include:(1) direct storage in pressurized cylinders, (2) storage of krypton adsorbed on charcoal or zeolite in pressurized cylinders and (3) immobilization (encapsulation) in zeolite. A krypton storage facility using pressurized cylinders has been constructed in the krypton recovery pilot plant in Tokaimura and other methods are now under development. These three methods are evaluated and the features of the constructed facility are also reported. (author)

Monitoring and assay procedures for krypton-85 used in circulatory tests

Energy Technology Data Exchange (ETDEWEB)

Brown, Jr., J. M.; Williams, K. D.

1963-11-15

During the past five years, krypton-85 has been used extensively at the National Institutes of health and by the heart Catheterization laboratory in the identification of circulatory shunts. Several methods of assaying the incoming shipments of radioactive gas are given. These consist of ionization chamber measurements, gamma ray spectrometry, and gross photon counting of the cylinder surface with an end-window Geiger-Mueller tube. A device (consisting of a log-count-rate meter, recorder, and G.M. tube) is used to continuously monitor the laboratory. The method of calibrating this device is presented. A means for removing contaminated air from the vicinity of the operating table was devised. The results of air clearance studies of the room are included. (auth)

Irradiation temperature memorization by retention of krypton-85. Application to the temperature determination for the internal cladding surface of fuel elements in PWR

International Nuclear Information System (INIS)

Fremiot, Claude

1977-01-01

The temperature of the inner surface of the cladding fuel elements, which can not be measured directly, can be determined after irradiation. During its stage within the reactor, the cladding is bombarded by krypton-85 fission product, which is trapped in the metallic lattice defects. The experience shows that the krypton release during postirradiation heating takes place at the irradiation temperature. This method was applied for PWR fuel element. A very simple model for retention and release of the krypton is proposed. The krypton trap-energy in zircaloy partakes in this model. This technique can be ordered amongst the Hot'Lab' control methods and expert appraisements. It is pointed out that the principal interest in that method is the fact that it does not need any fuel element instrumentation. At the present, this method is being used by CEA for routine-control. [fr

Facility for the separation of krypton and recuperation of xenon

International Nuclear Information System (INIS)

Boell-Djoa, S.H.

1977-01-01

A facility is described by means of which the fission inert gases krypton 85 and xenon from spent fuel particles can be separated by fractionated freezing-out and subsequent distillation to such an extent that the xenon contains less than 1 ppb krypton 85. Then, in accordance with the stringent regulations, the krypton can be conveyed to definitive storage in special bottles, whereas the xenon can be released for industrial uses. (orig.) [de

Choice of materials for the immobilization of 85-krypton in a metallic matrix by combined ion implantation and sputtering

International Nuclear Information System (INIS)

Whitmell, D.S.

1985-01-01

Immobilization in a metal matrix by combined ion implantation and sputtering promises to offer an ideal method for the containment of krypton-85 arising from the reprocessing of nuclear fuel. A 50 kW inactive pilot plant has been built and operated to prepare a copper deposit 22 mm thick weighing 23 kg and containing over 30 liters of inactive gas. The gas incorporation rate exceeded the design figure of 0.3 liters/hour and the vessel was operated at powers up to 30 kW, which corresponds to that envisaged for the industrial vessel. The power consumption was less than 100 kWh/liter. A full-scale vessel (1 m long, 0.26 m diameter) has also been tested at low power. Samples of alternative candidate materials: stainless steel, incoloy, nickel and nickel-lanthanum have been prepared and tested. Nickel appears to be the most promising since it incorporates gas with an efficiency 70% greater than copper and also retains the gas to a temperature at least 100 0 C higher than copper. Tests are being carried out with 100 Curies of radioactive krypton in order to demonstrate that the process will operate satisfactorily at the high internal β irradiation levels that will exist in an active plant and to prepare samples containing krypton-85 for long term leakage measurements and for assessment of any effects caused by the build-up of the decay product rubidium

Krypton recovery from reprocessing off-gases by cryogenic distillation

International Nuclear Information System (INIS)

Geens, L.P.; Goossens, W.R.A.; Marien, J.

1987-01-01

With the financial support of the C.E.C., krypton recovery by cryogenic distillation in presence of oxygen was investigated. Both oxygen and ozone behavior in the cryodistillation unit were observed. The ozone decay in the rectification column was studied in absence and in presence of a radiation source. Additionally a demonstration run with krypton-85 was performed. Experiments with different oxygen concentrations up to 21% volume in the feed gas were carried out. The oxygen was enriched up to 85% volume in a zone between the krypton layer and the entrance of the rectification column. No oxygen was found in the bottom product. On the other hand, the ozone accumulated in that bottom product. The decay of ozone in the bottom liquid was measured in absence and in presence of a 500 Ci thulium-170 source. Without the radiation source, it took almost 30 days to observe a decay from 0.90% volume to 0.45% volume. The decay rate decreased with decreasing ozone concentration. In presence of the 500 Ci thulium-170, a constant decay rate of 0.24% volume per day was measured. Finally, a demonstration run with 100 Ci krypton-85 was performed in the cryodistillation unit, with air as feed gas. The krypton-85 was fed at a concentration of 30 mCih -1 until the total krypton inventory of the rectification column amounted to 40-45 Ci. The active run had a duration of 900 hours, during which no operational problems occurred. (orig.)

Krypton 85 at La Hague; Krypton 85 a La Hague

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-11-01

The gaseous effluents from the fuel reprocessing plant of Cogema-La Hague (France) are regularly measured and controlled. This paper reports on three press releases: the one of Cogema from November 6, 1998 concerning the impact of these effluents and the results of {sup 85}Kr measurements performed in the vicinity of the facility, and the two communiques of the French office of protection against ionizing radiations (OPRI) from November 13 and 20, 1998 relative to the environmental and human impacts of the {sup 85}Kr releases from the La Hague facility. (J.S.)

Radioactive kryptonates in the analysis of environmental samples

International Nuclear Information System (INIS)

Tolgyessy, J.

1986-01-01

The term ''radioactive Kryptonates'' is used for substances into which atoms or ions of the radioactive nuclide 85 Kr are incorporated. The basis of the use of radioactive Kryptonates in analytical chemistry is that during a chemical reaction the crystalline lattice of the kryptonated carrier is destroyed, the carrier consumed, and the radioactive krypton released (radio-release method). Analysis can be made with a calibration curve or by comparison with a standard. Radio-release methods with the aid of radioactive Kryptonates as analytical reagents are very useful for the analysis of environmental samples, e.g. for the determination of air pollutants (ozone, sulphur dioxide, fluorine, hydrogen fluoride, mercury); and water pollutants (oxygen, dichromate, vanadium, hydrochloric acid, sulphur dioxide). (author)

85Kr dating of groundwater

International Nuclear Information System (INIS)

Rozanski, K.; Florkowski, T.

1978-01-01

The possibility of 85 Kr dating of groundwater is being investigated. The method of gas extraction from 200 to 300 litres of water sample has been developed. The Argon and Krypton mixture, separated from the gas extracted from water, was counted in a 1.5 ml volume proportional counter. The amount of krypton gas in the counter was determined by mass spectrometry. A number of surface and groundwater samples were analyzed indicating an 85 Kr concentration ranging from present atmospheric content (river water) to zero values. 85 Kr 'blank value' was determined to be about 5 per cent of present 85 Kr atmospheric content. For groundwater samples, the mean residence time in the system was calculated assuming the exponential model and known 85 Kr input function. Further improvement of the method should bring higher yield of krypton separation and lower volume of water necessary for analysis. (orig.) [de

Innovative method for ultra-sensitive measurement of krypton isotopes

International Nuclear Information System (INIS)

Lavielle, B.; Gilabert, E.; Thomas, B.; Rebeix, R.; Canchel, G.; Moulin, C.; Topin, S.; Pointurier, F.

2015-01-01

Kr 81 (T 1/2 = 2.29*10 5 y), that is produced in the atmosphere by cosmic rays and Kr 85 (T 1/2 = 10.77 y), that is produced in the fission of nuclear fuels, are considered as the right chronometer elements for the dating of underground waters, polar ice, of for tracking civil and military nuclear activities. The use of Kr 81 and Kr 85 implies the development of extracting lines and detection devices with so high accuracy that only a few thousands of krypton atoms can be detected. The approach developed aims at detecting Kr 81 and Kr 85 in 1 liter of air and 20 liters of water. 3 steps are necessary. The first step consists in separating and purifying the krypton. The extraction of gases from water is made by helium bubbling. Chemically active gases like N 2 , CO 2 , CH 4 and O 2 are eliminated by chemical traps while Ar si separated by cryogenics. The second step involves a double focus mass spectrometer designed to perform an important enrichment in Kr 81 and Kr 85 . The last step is the high-accuracy measurement of krypton isotopes performed with the new tool named FAKIR (Facility for Analyzing Krypton Isotopic Ratios) that is based on UV laser ionization and on the mass-discrimination of the ions through their time of flight

A study of the atmospheric dispersion of a high release of krypton-85 above a complex coastal terrain, comparison with the predictions of Gaussian models (Briggs, Doury, ADMS4).

Science.gov (United States)

Leroy, C; Maro, D; Hébert, D; Solier, L; Rozet, M; Le Cavelier, S; Connan, O

2010-11-01

Atmospheric releases of krypton-85, from the nuclear fuel reprocessing plant at the AREVA NC facility at La Hague (France), were used to test Gaussian models of dispersion. In 2001-2002, the French Institute for Radiological Protection and Nuclear Safety (IRSN) studied the atmospheric dispersion of 15 releases, using krypton-85 as a tracer for plumes emitted from two 100-m-high stacks. Krypton-85 is a chemically inert radionuclide. Krypton-85 air concentration measurements were performed on the ground in the downwind direction, at distances between 0.36 and 3.3 km from the release, by neutral or slightly unstable atmospheric conditions. The standard deviation for the horizontal dispersion of the plume and the Atmospheric Transfer Coefficient (ATC) were determined from these measurements. The experimental results were compared with calculations using first generation (Doury, Briggs) and second generation (ADMS 4.0) Gaussian models. The ADMS 4.0 model was used in two configurations; one takes account of the effect of the built-up area, and the other the effect of the roughness of the surface on the plume dispersion. Only the Briggs model correctly reproduced the measured values for the width of the plume, whereas the ADMS 4.0 model overestimated it and the Doury model underestimated it. The agreement of the models with measured values of the ATC varied according to distance from the release point. For distances less than 2 km from the release point, the ADMS 4.0 model achieved the best agreement between model and measurement; beyond this distance, the best agreement was achieved by the Briggs and Doury models.

Recovery of krypton-85 from dissolver off-gas streams

International Nuclear Information System (INIS)

Law, J.P.; Lamb, K.M.

1988-01-01

The Rare Gas Plant at the Idaho Chemical Processing Plant Recovers fission product krypton and xenon from dissolver off gas streams. Recently the system was upgraded to allow processing of hydrogen rich dissolver off-gas streams. A trickle bed hydrogen recombiner was installed and tested. The Rare Gas Plant can now safely process gas streams containing up to 80% hydrogen

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1980-01-01

Radioactive krypton-85 is released to the atmosphere in the off-gas from nuclear reprocessing plants. Three main methods have been suggested for removal of krypton from off-gas streams: cryogenic distillation; fluorocarbon absorption; and adsorption on solid sorbents. Use of solid adsorbents is the least developed of these methods, but offers the potential advantages of enhanced safety and lower operating costs. An experimental laboratory program was developed that will be used to investigate systematically many solid adsorbents (such as zeolites, i.e., mordenites) for trapping krypton in air. The objective of this investigation is to find an adsorbent that is more economical than silver-exchanged mordenite. Various physical and chemical characteristics such as adsorption isotherms, decontamination factors, co-adsorption, regeneration, and the mechanism and kinetics of noble gas adsorption were used to characterize the adsorbents. In the experimental program, a gas chromatograph using a helium ionization detector was used to measure the krypton in air before and after the adsorbent bed. This method can determine directly decontamination factors greater than 100

A new model validation database for evaluating AERMOD, NRPB R91 and ADMS using krypton-85 data from BNFL Sellafield

International Nuclear Information System (INIS)

Hill, R.; Taylor, J.; Lowles, I.; Emmerson, K.; Parker, T.

2004-01-01

The emission of krypton-85 ( 85 Kr) from nuclear fuel reprocessing operations provide a classical passive tracer for the study of atmospheric dispersion. This is because of the persistence of this radioisotope in the atmosphere, due to its long radioactive halflife and inert chemistry; and the low background levels that result due to the limited number of anthropogenic sources globally. The BNFL Sellafield site in Cumbria (UK) is one of the most significant point sources of 85 Kr in the northern hemisphere, with 85 Kr being discharged from two stacks on the site, MAGNOX and THORP. Field experiments have been conducted since October 1996 using a cryogenic distillation technique (Janssens et al., 1986) to quantify the ground level concentration of 85 Kr. This paper reports on the construction of a model validation database to allow evaluation of regulatory atmospheric dispersion models using the measured 85 Kr concentrations as a tracer. The results of the database for local and regional scale dispersion are presented. (orig.)

Krypton isotope analysis using near-resonant stimulated Raman spectroscopy

International Nuclear Information System (INIS)

Whitehead, C.A.; Cannon, B.D.; Wacker, J.F.

1994-12-01

A method for measuring low relative abundances of 85 Kr in one liter or less samples of air has been under development here at Pacific Northwest Laboratory. The goal of the Krypton Isotope Laser Analysis (KILA) method is to measure ratios of 10 -10 or less of 85 Kr to more abundant stable krypton. Mass spectrometry and beta counting are the main competing technologies used in rare-gas trace analysis and are limited in application by such factors as sample size, counting times, and selectivity. The use of high-resolution lasers to probe hyperfine levels to determine isotopic abundance has received much attention recently. In this study, we report our progress on identifying and implementing techniques for trace 85 Kr analysis on small gas samples in a static cell as well as limitations on sensitivity and selectivity for the technique. High-resolution pulsed and cw lasers are employed in a laser-induced fluorescence technique that preserves the original sample. This technique, is based on resonant isotopic depletion spectroscopy (RIDS) in which one isotope is optically depleted while preserving the population of a less abundant isotope. The KILA method consists of three steps. In the first step, the 1s 5 metastable level of krypton is populated via radiative cascade following two-photon excitation of the 2p 6 energy level. Next, using RBDS, the stable krypton isotopes are optically depleted to the ground state through the 1s 4 level with the bulk of the 85 Kr population being preserved. Finally, the remaining metastable population is probed to determine 85 Kr concentration. The experimental requirements for each of these steps are outlined below

Simulating the mesoscale transport of krypton-85.

Science.gov (United States)

Felsberg, Anne; Ross, J Ole; Schlosser, Clemens; Kirchner, Gerald

2018-01-01

Due to its half-life, chemical inertness and low solubility in water, radioactive 85 Kr is a valuable tracer for testing the performance of atmospheric dispersion models in simulating long-range transport of pollutants. This paper evaluates the capability of simulating the dispersion of radiokrypton emitted by a nuclear fuel reprocessing plant in north-west France. Three time periods during which elevated activity concentrations of 85 Kr in ground level air were detected in south-west Germany are chosen. Simulations have been performed using the HYSPLIT code and the European Centre for Median-Range Weather Forecasts (ECMWF) data base. Although their results show a slight trend of underestimating the measured 85 Kr concentrations, there is a significant correlation and moderate scatter between observations and simulations with about 50% of the results being within a factor of two of the measured concentrations. The simulated travel time distributions provided a valuable tool for providing additional insight into the dispersion of the tracer radionuclides and for identifying potential causes of deviations between measured and calculated concentrations. Copyright © 2017. Published by Elsevier Ltd.

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. I

International Nuclear Information System (INIS)

Toelgyessy, J.; Dillinger, P.; Harangozo, M.; Jombik, J.

1980-01-01

A method for the determination of salicylic, acetylsalicylic and benzoic acids in officinal pharmaceutical based on radiometric titration with 0.1 mol.l -1 NaOH was developed. The end-point was detected with the aid of radioactive glass kryptonate. After the end-point, the excess titrant attacks the glass surface layers and this results in releasing 85 Kr, and consequently, in decreasing the radioactivity of the kryptonate employed. The radioactive kryptonate used as an indicator was prepared by the bombardment of glass with accelerated 85 Kr ions. The developed method is simple, accurate and correct. (author)

Simulation of atmospheric krypton-85 transport to assess the detectability of clandestine nuclear reprocessing

Energy Technology Data Exchange (ETDEWEB)

Ross, Jens Ole

2010-02-02

The radioactive noble gas krypton-85 is released into the atmosphere during reprocessing of spent nuclear fuel or irradiated breeding targets. This is a necessary step for plutonium separation. Therefore the {sup 85}Kr signature of reprocessing could possibly be used for the detection of undeclared nuclear facilities producing nuclear weaponusable material. The {sup 85}Kr content of the atmosphere has grown over the last decades as the emissions from military and civilian nuclear industry could not be compensated by the decay with a half-life of 10.76 years. In this study, the global {sup 85}Kr background distribution due to emissions of known reprocessing facilities for the period from 1971 until 2006 was simulated using the atmospheric general circulation model ECHAM5 applying the newest available annual emission data. The convective tracer transport scheme and the operator splitting for the physical calculations in the model were modified in order to guarantee physically correct results for tracer point sources, in particular non negative concentrations. An on-line routine controlling the {sup 85}Kr -budget in the model enforced exact mass conservation. The results of the simulation were evaluated by extensive comparison with measurements performed by the German Federal Office for Radiation Protection with very good agreement at most observation sites except those in the direct vicinity of {sup 85}Kr sources. Of particular interest for the {sup 85}Kr detection potential was the variability of {sup 85}Kr background concentrations which was evaluated for the first time in a global model. In addition, the interhemispheric transport as simulated by ECHAM5 was analyzed using a two-box model providing a mean exchange time of τ {sub ex} = 10.5 months. The analysis of τ{sub ex} over simulated 35 years indicates that in years with strong South Asian or African Monsoon the interhemispheric transport is faster during the monsoon season. A correlation analysis of

Desublimation of krypton from a noncondensable carrier gas

International Nuclear Information System (INIS)

Eby, R.S.

1978-09-01

A study was conducted to obtain column concentration profiles and point buildup rates for a cold trap freezing out krypton from a nitrogen carrier gas stream and to compare those experimentally obtained profiles with profiles generated from a theoretical model. Profiles were obtained over a range of flow conditions from 0.14 to 1.06 standard cubic feet per minute, krypton feed gas concentrations varied from 5.2 to 13.5%, and cold trap operating temperatures from -281 to -312 0 F. Gamma scintillation techniques using tracer amounts of krypton-85 provided the major analytical tool employed in the investigation. Data obtained from the experiments indicate that if values for the density and thermal conductivity of the krypton frost are known, the model can accurately predict krypton loading profiles in the cold trap. The frost density and frost conductivity appear to be functions of the freeze-out temperature and condensable krypton concentration. A discussion of cold trapping theory, a description of the experimental apparatus and tests performed, and an explanation of the usefulness of the model as a design tool for engineering use are included

Adsorption of krypton from helium by low temperature charcoal

International Nuclear Information System (INIS)

Cooper, M.H.; Simmons, C.R.; Taylor, G.R.

1975-01-01

Adsorption of krypton from helium by charcoal at temperatures from -100 0 C to -140 0 C was experimentally investigated to verify adsorption system design methods and to determine effects of regeneration for the Gas Purification System of the Liquid-Metal Fast Breeder Reactor. Helium with two krypton concentrations, traced by krypton-85 at 0.0044 μCi/cm 3 , was passed through a 1/2-inch diameter, three-inch long trap packed with coconut charcoal. Breakthrough curves were measured by continuously recording the activity of the effluent gas using a sampler with a krypton-85 detection limit of about 5 x 10 -7 μCi/cm 3 . Experimental breakthrough curves with continuous feed for both concentrations and for superficial gas velocities of 5 to 28 cm/sec were closely fitted when the pore diffusion term was omitted from the Anzelius linear equilibrium adsorption model indicating that the adsorption process for this system was controlled by gas phase mass transport kinetics. Adsorption capacities determined in these experiments at -140 0 C agreed closely with published data. A discontinuity, however, was observed in the krypton adsorption coefficient between -100 and -120 0 C. This discontinuity may be caused by capillary condensation of krypton in the charcoal pores. Breakthrough times for pulse experiments at 400 ppM (vol.) krypton concentration were several times greater than breakthrough for continuous feed experiments at equivalent conditions. The differences in breakthrough times indicate that the adsorption isotherms are non-linear in this concentration range. Regeneration experiments showed that purging with helium at room temperature for 16 hours was inadequate, since lower breakthrough times were obtained after this treatment. Regeneration under vacuum at 100 0 C or 200 0 C for 16 hours resulted in satisfactory regeneration (i.e., no reduction in breakthrough times occurred in subsequent runs). (U.S.)

Environmental monitoring for krypton-85

International Nuclear Information System (INIS)

Barber, D.E.

1973-01-01

85 Kr presents unique environmental monitoring problems because it does not react with other elements and compounds at normal ambient temperatures and pressures. However, elaborate means are available to manage the 85 Kr problem, but a simpler, inexpensive approach is required if monitoring is to be accomplished at many sampling locations. This work shows that environmental monitoring for 85 Kr is possible by collecting air samples in thin plastic bags, and counting the bags for beta particle activity. The direct counting of contained samples of this type makes it possible to detect concentrations less than the public MPC for 85 Kr. The bagged-sample technique is readily adaptable to any environmental monitoring station with power to run a low-volume air pump. The idea of counting the bagged-sample directly is a new, low-cost, approach to environmental gas monitoring which may have application in environmental, clinical, and industrial situations

Krypton purification (1961); Purification du krypton (1961)

Energy Technology Data Exchange (ETDEWEB)

Larher, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Institut Fourier, 38 - Grenoble (France)

1961-07-01

The amount of xenon in otherwise very pure krypton can be reduced from 1.5 to 0.0025 per cent approximately by passage through an activated carbon column at dry-ice temperature. The circulation of the krypton is effected by condensing at -196 deg. C and then evaporating. (author) [French] Le taux de xenon dans du krypton par ailleurs tres pur est ramene de 1,5 pour cent a 0,0025 pour cent environ au cours d'un passage a travers une colonne de charbon actif a la temperature de la carboglace. La circulation du krypton se fait par condensation a -196 deg. C, puis evaporation. (auteur)

Report of the krypton club: availability of sup(81m)krypton in europe

International Nuclear Information System (INIS)

Clark, J.; Watson, I.

1982-01-01

An active group of producers of krypton 81m generators has been formed. They met in Liege 27th February 1981 to discuss the technical and logistics problems in making krypton 81m generators more widely available in Europe. A resume of that meeting was prepared and distributed at two major medicine meetings in 1981, Pisa and Berne, in an attempt to alert potential users to the current situation and encourage them to make contact with the production centre most favourably situated logistically. (Author)

Krypton-85 removal and storage

International Nuclear Information System (INIS)

Gutierrez Fernandez, J.

1978-01-01

A literature survey was made in order to predict the atmospheric Kr-85 concentration in the future and it s effect on the population. As a consequence the need for its treatment and removal as a previous step to gaseous waste disposal is justified. A literature review of possible methods of Kr-85 removal and storage is also included. (Author) 43 refs

Solid state storage of radioactive krypton in a silica matrix

International Nuclear Information System (INIS)

Tingey, G.L.; Lytle, J.M.; Gray, W.J.; Wheeler, K.R.

1980-12-01

The feasibility of loading a low density SiO 2 glass with krypton for storage of radioactive 85 Kr has been demonstrated by studies using non-radioactive krypton. A 96% SiO 2 glass with 28% porosity was heated at an elevated pressure of Kr gas to a temperature of 850 to 900 0 C and held at that temperature to sinter the glass-krypton composite to a density of about 2 g/cm 3 . A krypton content of 30 cm 3 of Kr(STP)/cm 3 of glass has been demonstrated when loading pressures of 140 MPa are used. Krypton release rates from the glass are lower than reported for any other waste form considered currently. At 420 0 C a diffusion parameter, D/r 0 2 , of 8.66 x 10 -13 min -1 was determined which leads to a total release of 0.7% of the krypton in 10 years. Release rates increase moderately with increasing temperature up to 600 0 C and increase rapidly above 600 0 C. The lower loading pressures (about 40 MPa) may appear to yield a more favorable product from the point of view of krypton release than the high pressures. Advantages and disadvantages of the technique are given in the conclusions section

Krypton-enhanced ventilation CT with dual energy technique: experimental study for optimal krypton concentration.

Science.gov (United States)

Chung, Yong Eun; Hong, Sae Rom; Lee, Mi-Jung; Lee, Myungsu; Lee, Hye-Jeong

2014-11-01

To assess the feasibility of krypton-enhanced ventilation CT using dual energy (DE) technique for various krypton concentrations and to determine the appropriate krypton concentration for DE ventilation CT through an animal study. Baseline DECT was first performed on seven New Zealand white rabbits. The animals were then ventilated using 20%, 30%, 40%, 50%, 60%, to 70% krypton concentration, and DECT was performed for each concentration. Krypton extraction was performed through a workstation, and results were displayed on a color map. Overlay Hounsfield unit (HU) values were obtained by two observers in consensus readings. A linear mixed model was used to correlate overlay HU values and krypton concentrations. Visual assessments of the homogeneity of krypton maps were also performed. Mean overlay HU values according to krypton concentration were as follows; 20% krypton, 1.68 ± 5.15; 30% krypton, 3.73 ± 5.93; 40% krypton, 6.92 ± 5.51; 50% krypton, 10.88 ± 5.17; 60% krypton, 14.54 ± 4.23; and 70% krypton, 18.79 ± 3.63. We observed a significant correlation between overlay HU values on krypton maps and krypton concentrations (P krypton color maps, all observers determined universal enhancement on the 70% krypton map for all animals. It is feasible to evaluate lung ventilation function using DECT with a krypton concentration of at least 70%.

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. I. Salicylic, acetylosalicylic, benzoic acids

Energy Technology Data Exchange (ETDEWEB)

Toelgyessy, J; Dillinger, P [Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia). Chemickotechnologicka Fakulta; Harangozo, M; Jombik, J [Komenskeho Univ., Bratislava (Czechoslovakia). Farmaceuticka Fakulta

1980-01-01

A method for the determination of salicylic, acetylsalicylic and benzoic acids in officinal pharmaceutical based on radiometric titration with 0.1 mol.l/sup -1/ NaOH was developed. The end-point was detected with the aid of radioactive glass kryptonate. After the end-point, the excess titrant attacks the glass surface layers and this results in releasing /sup 85/Kr, and consequently, in decreasing the radioactivity of the kryptonate employed. The radioactive kryptonate used as an indicator was prepared by the bombardment of glass with accelerated /sup 85/Kr ions. The developed method is simple, accurate and correct.

Krypton 85 at La Hague

International Nuclear Information System (INIS)

1998-11-01

The gaseous effluents from the fuel reprocessing plant of Cogema-La Hague (France) are regularly measured and controlled. This paper reports on three press releases: the one of Cogema from November 6, 1998 concerning the impact of these effluents and the results of 85 Kr measurements performed in the vicinity of the facility, and the two communiques of the French office of protection against ionizing radiations (OPRI) from November 13 and 20, 1998 relative to the environmental and human impacts of the 85 Kr releases from the La Hague facility. (J.S.)

Krypton-81 dating of old groundwater. Chapter 5

International Nuclear Information System (INIS)

Purtschert, R.; Yokochi, R.; Sturchio, N.C.

2013-01-01

The abundance of krypton in the atmosphere has been quoted for nearly half a century as 1.14 ± 0.01 ppm, which corresponds to a total atmospheric inventory of 4.51 × 10 12 m 3 STP (Verniani (1966) [243]). A recent re-evaluation yielded a value of 1.099 ± 0.009 ppmv, which is about 4% lower than the previously used value (Aoki and M akide (2005) [244]). Krypton has six stable isotopes of which 84 Kr is the most abundant, comprising about 57% of natural Kr (Table 5.1). Eleven major radioactive isotopes of Krexist but only 81 Kr and 85 Kr, with halflives of 229 000 and 10.76 a, respectively, exceed 2 d and are, therefore, suitable for the investigation of environmental processes. Krypton-81 is produced in the atmosphere by cosmic ray induced spallation of heavier stable Krisotopes and by the nuclear reactions 80 Kr(n, γ) 81 Kr and 82 Kr(γ, n) 81 Kr.

Charge state distribution studies of pure and oxygen mixed krypton ECR plasma - signature of isotope anomaly and gas mixing effect.

Science.gov (United States)

Kumar, Pravin; Mal, Kedar; Rodrigues, G

2016-11-01

We report the charge state distributions of the pure, 25% and 50% oxygen mixed krypton plasma to shed more light on the understanding of the gas mixing and the isotope anomaly [A. G. Drentje, Rev. Sci. Instrum. 63 (1992) 2875 and Y Kawai, D Meyer, A Nadzeyka, U Wolters and K Wiesemann, Plasma Sources Sci. Technol. 10 (2001) 451] in the electron cyclotron resonance (ECR) plasmas. The krypton plasma was produced using a 10 GHz all-permanent-magnet ECR ion source. The intensities of the highly abundant four isotopes, viz. 82 Kr (~11.58%), 83 Kr (~11.49%), 84 Kr (~57%) and 86 Kr (17.3%) up to ~ +14 charge state have been measured by extracting the ions from the plasma and analysing them in the mass and the energy using a large acceptance analyzer-cum-switching dipole magnet. The influence of the oxygen gas mixing on the isotopic krypton ion intensities is clearly evidenced beyond +9 charge state. With and without oxygen mixing, the charge state distribution of the krypton ECR plasma shows the isotope anomaly with unusual trends. The anomaly in the intensities of the isotopes having quite closer natural abundance, viz. 82 Kr, 86 Kr and 83 Kr, 86 Kr is prominent, whereas the intensity ratio of 86 Kr to 84 Kr shows a weak signature of it. The isotope anomaly tends to disappear with increasing oxygen mixing in the plasma. The observed trends in the intensities of the krypton isotopes do not follow the prediction of linear Landau wave damping in the plasma. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Angular distribution of Auger electrons due to 3d-shell ionization of krypton

Science.gov (United States)

Omidvar, K.

1977-01-01

Cross sections for electron impact ionization of krypton due to ejection of a 3rd shell electron have been calculated using screened hydrogenic and Hartree-Slater wave functions for target atom. While the total ionization cross sections in the two approximations are within 10% of each other, the Auger electron angular distribution, related to cross sections for specific magnetic quantum numbers of the 3rd electrons, is widely different in the two approximations. The angular distribution due to Hartree-Slater approximation is in excellent agreement with measurement. The physical reason for the discrepancies in the two approximations is explained.

Using zeolites for fixation and long-term storage of krypton

International Nuclear Information System (INIS)

Pirogova, G.N.; Voronin, Yu.V.; Pribylov, A.A.; Serpinskii, V.V.; Mirskii, Ya.V.; Almazova, B.B.; Golitsina, V.V.

1993-01-01

It is known that large quantities of 85 Kr are liberated during the operation of nuclear power plants and, in particular, during the processing of nuclear fuel. At the present time, there are several methods of its fixation (accumulation), viz., storage in high-pressure gas balloons, adsorption, plasma-aided implantation into metals, introduction into clathrate compounds, and obtaining kryptonates. Encapsulation in zeolites is one of the most promising methods. The merits of this method include safety during storage, a favorable volume-to-mass ratio, the possibility of separating krypton from a mixture of different gases, and purity of the encapsulated gas. The encapsulation technique has been developed quite recently. Several recent reports established the possibility of encapsulating krypton in the 3A-type zeolites. However, most of the investigators observed leakage during the storage of the zeolite-gas system and complete liberation of krypton from the zeolite during prolonged storage. This paper deals with a study of the encapsulation process of krypton in the zeolites obtained by cation exchange from NaA. The experimental specimens were characterized by the degree of exchange of sodium into potassium and cesium. It is known that the introduction of cesium into the structure (body) of a zeolite reduces the size of the window of entrance. All the synthesized specimens were used in their granulated form. The aim of this study was to develop zeolite specimens for carrying out long-term storage of krypton

Experience gained in the cryodistillation unit for krypton removal

International Nuclear Information System (INIS)

Geens, L.; Collard, G.; Goossens, W.R.A.; Vaesen, P.J.

1981-08-01

This unit with a nominal gas throughput of 8.5 g.s -1 has been used to investigate the removal of krypton from reprocessing off-gases under non-radioactive conditions. During the investigation a total operation time of more than 13.000 hours was reached with an average availability factor of 99.36%. The trapping efficiency for krypton was higher than 99.9%. The operation experience acquired indicates some critical aspects for the design of such a unit. The experimental results obtained allow to show the influence of feed pressure and temperature, reflux flow rate and noble gas concentrations on the performance of the unit. (author)

New method of 85Kr reduction in a noble gas based low-background detector

Science.gov (United States)

Akimov, D. Yu.; Bolozdynya, A. I.; Burenkov, A. A.; Hall, C.; Kovalenko, A. G.; Kuzminov, V. V.; Simakov, G. E.

2017-04-01

Krypton-85 is an anthropogenic beta-decaying isotope which produces low energy backgrounds in dark matter and neutrino experiments, especially those based upon liquid xenon. Several technologies have been developed to reduce the Kr concentration in such experiments. We propose to augment those separation technologies by first adding to the xenon an 85Kr-free sample of krypton in an amount much larger than the natural krypton that is already present. After the purification system reduces the total Kr concentration to the same level, the final 85Kr concentration will be reduced even further by the dilution factor. A test cell for measurement of the activity of various Kr samples has been assembled, and the activity of 25-year-old krypton has been measured. The measured activity agrees well with the expected activity accounting for the 85Kr abundance of the earth's atmosphere in 1990 and the half-life of the isotope. Additional tests with a Kr sample produced in the year 1944 (before the atomic era) have been done in order to demonstrate the sensitivity of the test cell.

New method of 85Kr reduction in a noble gas based low-background detector

International Nuclear Information System (INIS)

Akimov, D.Yu.; Burenkov, A.A.; Kovalenko, A.G.; Simakov, G.E.; Bolozdynya, A.I.; Hall, C.; Kuzminov, V.V.

2017-01-01

Krypton-85 is an anthropogenic beta-decaying isotope which produces low energy backgrounds in dark matter and neutrino experiments, especially those based upon liquid xenon. Several technologies have been developed to reduce the Kr concentration in such experiments. We propose to augment those separation technologies by first adding to the xenon an 85 Kr-free sample of krypton in an amount much larger than the natural krypton that is already present. After the purification system reduces the total Kr concentration to the same level, the final 85 Kr concentration will be reduced even further by the dilution factor. A test cell for measurement of the activity of various Kr samples has been assembled, and the activity of 25-year-old krypton has been measured. The measured activity agrees well with the expected activity accounting for the 85 Kr abundance of the earth's atmosphere in 1990 and the half-life of the isotope. Additional tests with a Kr sample produced in the year 1944 (before the atomic era) have been done in order to demonstrate the sensitivity of the test cell.

Spectra of heliumlike krypton from tokamak fusion test reactor plasmas

International Nuclear Information System (INIS)

Bitter, M.; Hsuan, H.; Bush, C.; Cohen, S.; Cummings, C.J.; Grek, B.; Hill, K.W.; Schivell, J.; Zarnstorff, M.; Smith, A.; Fraenkel, B.

1993-04-01

Krypton has been injected into ohmically-heated TFTR plasmas with peak electron temperatures of 6 key to study the effects of krypton on the plasma performance and to investigate the emitted krypton line radiation, which is of interest for future-generation tokamaks such as ITER, both as a diagnostic of the central ion temperature and for the control of energy release from the plasma by radiative cooling. The emitted radiation was monitored with a bolometer array, an X-ray pulse height analysis system, and a high-resolution Johann-type crystal spectrometer; and it was found to depend very sensitively on the electron temperature profile. Satellite spectra of heliumlike krypton, KrXXXV, near 0.95 Angstrom including lithiumlike, berylliumlike and boronlike features were recorded in second order Bragg reflection. Radiative cooling and reduced particle recycling at the plasma edge region were observed as a result of the krypton injection for all investigated discharges. The observations are in reasonable agreement with modeling calculations of the krypton ion charge state distribution including radial transport

Angular distribution of Auger electrons due to 3d-shell impact ionization of krypton

Science.gov (United States)

Omidvar, K.

1977-01-01

Cross sections for electron impact ionization of krypton due to ejection of a 3d-shell electron have been calculated using screened hydrogenic and Hartree-Slater wavefunctions for the target atom. While the total ionization cross sections in the two approximations are within 10% of each other, the Auger electron angular distribution, related to cross sections for specific magnetic quantum numbers of the 3d electrons, are widely different in the two approximations. The angular distribution due to the Hartree-Slater approximation is in excellent agreement with measurement. The physical reason for the discrepancies in the two approximations is explained.

Krypton gas cylinders as a source of radiation.

Science.gov (United States)

Fischer, Helmut W; Bielefeld, Tom; Hettwig, Bernd

2010-07-01

A standard 40 foot shipping container with a cargo of pressurized krypton gas in 159 steel cylinders, which had triggered a radiation alarm, was investigated to address radiation safety and illicit nuclear trafficking concerns. The investigation included contamination and dose rate measurements as well as in situ high resolution gamma spectroscopy. The dose rate measurements gave a maximum value of 0.07 microSv h(-1) above background (0.08 to 0.11 microSv h(-1)) on the cylinder surface and no detectable increase above background at distances of 1 m and higher. Contamination monitor readings showed a similar relative increase (plus 8 cpm) above background (about 12 cpm) to the dose rate readings. Quantitative gamma spectroscopy revealed a contamination of the gas with 85Kr at a level of 3.5 x 10(5) Bq kg(-1). This value was found to be consistent with analytical and numerical estimates based on current data for atmospheric 85Kr, which is captured from ambient air together with stable krypton during the production process. This incident demonstrates an apparent lack of radiation-related knowledge by those who handle krypton gas, as well as by border control personnel and emergency responders. We therefore propose to improve labeling and documentation standards for such shipments. This effort may be facilitated by introducing the new category of "technically enhanced artificial radioactive material," or "TEARM" (similar to the existing "naturally occurring radioactive material" or "NORM" and "technically enhanced naturally occurring radioactive material" or "TENORM" categories).

Design and construction of a cryogenic distillation device for removal of krypton for liquid xenon dark matter detectors.

Science.gov (United States)

Wang, Zhou; Bao, Lei; Hao, Xihuan; Ju, Yonglin

2014-01-01

Liquid xenon (Xe) is one of the commendable detecting media for the dark matter detections. However, the small content of radioactive krypton-85 ((85)Kr) always exists in the commercial xenon products. An efficient cryogenic distillation system to remove this krypton (Kr) from commercial xenon products has been specifically designed, developed, and constructed in order to meet the requirements of the dark matter experiments with high- sensitivity and low-background. The content of krypton in regular commercial xenon products can be reduced from 10(-9) to 10(-12), with 99% xenon collection efficiency at maximum flow rate of 5 kg/h (15SLPM). The purified xenon gases produced by this distillation system can be used as the detecting media in the project of Panda X, which is the first dark matter detector developed in China.

Build up of Radioactive Krypton and Xenon Analysis System

International Nuclear Information System (INIS)

Lee, D. K.; Choi, C. S.; Chung, K. H.; Lee, W.; Cho, Y. H.; Lee, C. W.

2008-03-01

The objective of this project is to build up an analysis system to measure the activity of the atmospheric radioactive krypton and xenon in Korea. The work scopes of the project include the purchase and the installation of the analysis system to measure the activity of the radioactive krypton and xenon in air, and the establishment of the operation capability of the system through the training of the operator. The system consists of two air sampling systems, and one radioactivity analysis system, which incorporates the enrichment system, the gas chromatography to purify a mixture gas, and the gas proportional counter to count the activity of pure krypton and xenon gas. As planned originally, the establishment of the analysis system has been completed. At present, one air sampler is successfully being operated at a specific site of the South Korea to measure the background radioactivities of Kr-85 and Xe-133 in air. The other air sampler is being reserved at the KAERI in the Daejeon for a emergency like the second nuclear test of the North Korea. During the normal time, the reserved air sampler will be used to collect the air sample for the performance test of the analysis system and the cross analysis for the calibration of the system. The radioactivity analysis system has been installed at the KAERI, and is being used to measure the activity of Kr-85 and Xe-133 in the air sample from a domestic site

Radioactive krypton gas separation

International Nuclear Information System (INIS)

Martin, J.R.

1976-01-01

Radioactive krypton is separated from a gas mixture comprising nitrogen and traces of carbon dioxide and radioactive krypton by selective adsorption and then cryogenic distillation of the prepurified gas against nitrogen liquid to produce krypton bottoms concentrate liquid, using the nitrogen gas from the distillation for two step purging of the adsorbent. 16 Claims, 8 Drawing Figures

Transfert de responsabilités (2009) | CRDI - Centre de recherches ...

International Development Research Centre (IDRC) Digital Library (Canada)

25 avr. 2016 ... ... des principes directeurs susceptibles d'orienter les pratiques en matière de transfert de responsabilité. Évaluation du transfert de la responsabilité des secrétariats internationaux du Centre de recherches pour le développement international par Jim Armstrong et Alexa Khan The Governance Network ...

Krypton-85 removal and storage; Separacion y almacenamiento de Kripton-85

Energy Technology Data Exchange (ETDEWEB)

Gutierrez, J.

1978-07-01

A literature survey was made in order to predict the atmospheric Kr-85 concentration in the future and it s effect on the population. As a consequence the need for its treatment and removal as a previous step to gaseous waste disposal is justified. A literature review of possible methods of Kr-85 removal and storage is also included. (Author) 43 refs.

An experimental investigation of proton-induced phenomena in krypton

International Nuclear Information System (INIS)

Mulders, J.J.L.

1985-01-01

In this thesis proton-induced phenomena in krypton gas are described. The considered reactions of protons on krypton are both nuclear and atomic. The nuclear conversion processes mainly result in the production of several Rb radioisotopes, such as 81 Rb that is used in 81 Rb-sup(81m)Kr generator systems for medical diagnostics. The irradiation of krypton gas (natural composition) with protons of about 26 MeV can be used for the routine production of 81 Rb from the direct production reaction 82 Kr(p,2n) 81 Rb and from the indirect reaction 82 Kr(p,2n)sup(81m)Rb → 81 Rb. To determine the scattering of protons in krypton gas targets a quantitative autoradiographic technique was developed. Proton profiles have been determined from the proton-induced activity distribution on a copper foil. For the on-line detection of produced Rb radioisotopes several optical detection techniques were investigated. (Auth.)

Ambient krypton-85 air sampling at Hanford

International Nuclear Information System (INIS)

Trevathan, M.S.; Price, K.R.

1985-01-01

In the fall of 1982, the Environmental Evaluations Section of Pacific Northwest Laboratory (PNL) initiated a network of continuous 85 Kr air samplers located on and around the Hanford Site. This effort was in response to the resumption of operations at a nuclear fuel reprocessing plant located onsite where 85 Kr was to be released during fuel dissolution. Preoperational data were collected using noble gas samplers designed by the Environmental Protection Agency-Las Vegas (EPA-LV). The samplers functioned erratically resulting in excessive maintenance costs and prompted a search for a new sampling system. State-of-the-art 85 Dr sampling methods were reviewed and found to be too costly, too complex and inappropriate for field application, so a simple bag collection system was designed and field tested. The system is composed of a reinforced, heavy plastic bag, connected to a variable flow pump and housed in a weatherproof enclosure. At the end of the four week sampling period the air in the bag is transferred by a compressor into a pressure tank for easy transport to the laboratory for analysis. After several months of operation, the air sampling system has proven its reliability and sensitivity to ambient levels of 85 Kr

Retention of krypton on polymethyl methacrylate

International Nuclear Information System (INIS)

Ciric, M.M.; Cvjeticanin, N.M.; Radak, B.B.

1975-01-01

Retention of krypton on polymethyl methacrylate was studied as a function of kryptonation pressure (P), temperature (T) and time (t). It was found that the dependence of the retained quantity on P, T, and t is in accordance with the diffusion theory. The optimum results (i.e., the maximum retained quantity and the best stability of the kryptonate) were obtained at elevated kryptonation temperatures (200 0 C). The diffusion coefficients of krypton in polymethyl methacrylate, determined from the dekryptonation process, vary from 1 x 10 -10 cm 2 /s to 0.2 x 10 -10 cm 2 /s for samples kryptonated at 20 0 C and 200 0 C respectively. The results have been discussed from the viewpoint of radiation and thermal stability of kryptonated polymethyl methacrylate. Inadequate radiation stability could be the main obstacle for practical purposes. (U.S.)

Long-term storage of compressed radioactive krypton in cylinders

International Nuclear Information System (INIS)

Niephaus, D.; Nommensen, O.; Bruecher, H.

1982-01-01

The recommendations of the German Radiation Protection Commission necessitate the separation of the radioactive noble gas krypton-85 (Kr-85) produced in large LWR reprocessing plants from the dissolver off-gas. A possible method of removal is a long-term storage of the compressed noble gas above ground in cylinders. The aim of the present study is to develop such a storage concept and evaluate its feasibility under the aspects of safety and cost. After having been filled, the gas cylinders are placed separately into transport racks serving to protect the cylinders. Following this, the cylinders are transferred out of the filling station in a transport cask, conveyed to the storage building and stored there. The storage building protects the gas cylinders against external impacts. The storage cells constitute a second barrier against the release of Kr-85. The heat produced during decay of the Kr-85 in the gas cylinders is carried off by natural convection of the air circulating in the storage cells. To study possible corrosion attack on special steels due to rubidium, experiments were conducted at 200 0 C during test periods up to 3500h. In order to compare properties at elevated temperatures, corrosion experiments were conducted at 500 0 C, which is far above the maximum licensed storage temperature of 200 0 C. Experiments were conducted concerning the adsorption of krypton on various adsorbents, thus reducing the pressure inside the gas cylinder during storage. A cost estimate based on 1980 prices

Evaluation of target power supplies for krypton storage in sputter-deposited metals

International Nuclear Information System (INIS)

Greenwell, E.N.; McClanahan, E.D.; Moss, R.W.

1986-04-01

Implantation of 85 Kr in a growing sputtered metal deposit has been studied for the containment of 85 Kr recovered from the reprocessing of spent nuclear fuel. PNL, as part of DOE's research program for 85 Kr storage, has developed krypton trapping storage devices (KTSDs) in a range of sizes for ''cold'' and radioactive testing. The KTSD is a stainless steel canister that contains a sputtering target for depositing an amorphous rare-earth transition metal on the inner wall and simultaneously implanting low-energy krypton ions in the growing deposit. This report covers the design requirements for the target power supply and the description, testing and evaluation of three basic designs. The designs chosen for evaluation were: (1) a standard commercial power supply with an external PNL-designed current interrupter, (2) a commercially manufactured power supply with an integral series-type interrupter, and (3) a commercially manufactured power supply with an integral shunt-type interrupter. The units were compared on the basis of performance, reliability, and life-cycle cost. 8 refs., 9 figs., 2 tabs

Krypton oxides under pressure

OpenAIRE

Zaleski-Ejgierd, Patryk; Łata, Paweł

2015-01-01

Under high pressure, krypton, one of the most inert elements is predicted to become sufficiently reactive to form a new class of krypton compounds; krypton oxides. Using modern ab-initio evolutionary algorithms in combination with Density Functional Theory, we predict the existence of several thermodynamically stable Kr/O species at elevated pressures. In particular, our calculations indicate that at approx. 300?GPa the monoxide, KrO, should form spontaneously and remain thermo- and dynamical...

Krypton purification (1961)

International Nuclear Information System (INIS)

Larher, Y.

1961-01-01

The amount of xenon in otherwise very pure krypton can be reduced from 1.5 to 0.0025 per cent approximately by passage through an activated carbon column at dry-ice temperature. The circulation of the krypton is effected by condensing at -196 deg. C and then evaporating. (author) [fr

The modified cryogenic adsorption method for the laboratory separation of sup(85)Kr from the atmosphere

International Nuclear Information System (INIS)

Wilhelmova, L.; Tomasek, M.; Dvorak, Z.

1985-01-01

A method for laboratory separation of sup(85)Kr from the atmosphere based on cryogenic adsorption technique was developed. The physical parameters of the separation equipment were chosen with respect to the properties of scintillation crystal CaFsub(2)(Eu) used as a detector of sup(85)Kr. The apparatus contains dry-ice, silica gel and molecular sieve traps for the removal of Hsub(2)O and COsub(2). The activated charcoal columns are used for concentration and preparation of krypton sample. The separation technique is supplemented by gas-chromatographic determination of total amount of separated krypton. The apparatus enables processing of up to 20 msup(3) of air with the krypton yield about 80%. The relative errors of the determination of the concentration of sup(85)Kr in the air by elaborated method is about 5%. (author)

Hyperfine spectra of the radioactive isotopes 81Kr and 85Kr

International Nuclear Information System (INIS)

Cannon, B.D.

1993-01-01

Isotope shifts and hyperfine constants are reported for the radioactive isotopes 81 Kr and 85 Kr and the stable isotope 83 Kr. The previously unreported nuclear moments of 81 Kr were determined to be μ I =-0.909(4) nuclear magneton and Q=+0.630(13) b from the hyperfine constants. This work increases the number of transitions for which 85 Kr hyperfine constants and isotope shifts have been measured from 1 to 4. The hyperfine anomaly for krypton reported in the previous measurement of 85 Kr hyperfine constants [H. Gerhardt et al., Hyperfine Interact. 9, 175 (1981)] is not supported by this work. The isotope shifts and hyperfine constants of 83 Kr measured in this work are in excellent agreement with previous work. Saturation spectroscopy was used to study transitions from krypton's metastable 1s 5 state to the 2p 9 , 2p 7 , and 2p 6 states. In saturation spectra, different line shapes were observed for the even- and odd-mass krypton isotopes. This even- versus odd-line-mass shape difference can be explained using the large cross section that has been reported for collisional transfer of the 1s 5 state excitation between krypton atoms. Two-color two-photon laser-induced fluorescence was used to measure the hyperfine spectra of the 1s 5- 4d 4 ' transition using the 2p 9 state as the intermediate state. This technique proved to be more sensitive than saturation spectroscopy

Krypton oxides under pressure.

Science.gov (United States)

Zaleski-Ejgierd, Patryk; Lata, Pawel M

2016-02-02

Under high pressure, krypton, one of the most inert elements is predicted to become sufficiently reactive to form a new class of krypton compounds; krypton oxides. Using modern ab-initio evolutionary algorithms in combination with Density Functional Theory, we predict the existence of several thermodynamically stable Kr/O species at elevated pressures. In particular, our calculations indicate that at approx. 300 GPa the monoxide, KrO, should form spontaneously and remain thermo- and dynamically stable with respect to constituent elements and higher oxides. The monoxide is predicted to form non-molecular crystals with short Kr-O contacts, typical for genuine chemical bonds.

Computer-controlled on-line gamma analysis for krypton-85

International Nuclear Information System (INIS)

Canuette, R.P.

1980-03-01

85 Kr will be evolved from spent nuclear fuel during both the voloxidation and dissolution processes, so a reliable method for on-line analysis of 85 Kr in the off-gas system is needed. Tritium, 14 C, and 129 I were trapped, and the activity of 85 Kr was then measured using a Li-drifted Ge detector. Equipment used to carry out this analysis is described; the PET computer is used. The 85 Kr evolution rate was correlated with the fuel dissolution rate; the close correlation permits one to monitor the fuel dissolution process. 11 figures

Atomic structure investigation of ionized krypton

International Nuclear Information System (INIS)

Kotze, P.B.

1981-12-01

The experimental lifetimes of ionized Krypton are discussed. Theoretical, the Coulomb approximation proves to be a reliable tool for the performance of calculations in Krypton II, where in general good agreement between experimental and theoretical lifetimes is reached, but its vulnerability is exposed in the case of Krypton III, where only results concerning levels with a 4p 3 ( 4 S 0 ) parent core can be obtained. Although the single configuration Hartree-Fock approximation turns out to be an adequate way of obtaining wave functions of excited states in Krypton III, cancellation effects resulting from configuration-interaction mixing, make the calculated transition probabilities in Krypton II less reliable. Previous work on configuration-interaction effects in the spectrum of Krypton II (El 76a, El 76b) reveals that good agreement between experimental and theoretical results can be obtained. A systematic theoretical analysis based on the multi-configurarion Hartree-Fock approximation to account for configuration-interaction effects should contribute a great deal to the existing knowledge of the energy spectra of ionized atoms

Process and device for the adsorptive separation of krypton from a krypton/nitrogen gas mixture

International Nuclear Information System (INIS)

Ringel, H.; Messler, M.

1985-01-01

The gas mixture flows through an adsorption column, which is filled with a means of adsorbing Krypton and nitrogen. The adsorption column is desorbed after adsorption of the gas components by a gaseous flushing material, which flows through the adsorption column in the same direction as the gas mixture. In order to achieve a high degree of separation, the adsorption material is loaded with nitrogen and Krypton from the gas inlet, where Krypton is only absorbed over part of the length of the whole column by the adsorption material. The part of the length is such that on desorption of the adsorption column with the flushing material at first only nitrogen and later only Krypton is obtained at the outlet of the adsorption column. (Waste gas system of a reprocession plant). (orig./HP) [de

Nuclear reactions and application to production rates of krypton in extraterrestrial materials

International Nuclear Information System (INIS)

Lavielle, B.

1982-01-01

Noble gases have been largely outgassed from most solar system materials through several heating processes. Consequently, their cosmogenic component, produced by cosmic-ray-induced nuclear reactions near the surface of atmosphere-free planetary objects, is detectable in meteorites and lunar samples. This work deals with the production of cosmogenic Krypton in the four main targets Zr, Y, Sr and Rb. Excitation functions of Krypton isotopes with A = 78, 80, 81, 82, 83, 84, 85 and 86 were mass-spectrometrically measured in Y and Zr targets bombarded with 0.059, 0.075, 0.168, 0.200, 1.0, 2.5 and 24 GeV protons. Also the Krypton relative cross sections were measured in Sr at 0.168 GeV. The results, combined with a general survey of nuclear reactions in Ga to Nb targets, permitted the development of new systematics in order to estimate unknown cross-sections in Rb and Sr. Measured and estimated excitation functions allowed to calculate the concentrations and isotopic ratios of cosmogenic Krypton in same well-documented lunar samples. Compared to observed values in 9 rocks, 83 Kr is predicted with a precision better than 33% and the production ratios sup(i)Kr/ 83 Kr are predicted to better than 25%. Also it is concluded that the cosmogenic ratios 86 Kr/ 83 Kr and 81 Kr/ 83 Kr are dependent on the main target elements concentrations [fr

Continuous determination of regional myocardial blood flow with intracoronary krypton-81m in coronary artery disease

International Nuclear Information System (INIS)

Remme, W.J.; Krauss, X.H.; van Hoogenhuyze, D.C.; Cox, P.H.; Storm, C.J.; Kruyssen, D.A.

1985-01-01

Pacing-induced changes in regional coronary flow were studied continuously with krypton-81m by intracoronary infusion in 25 patients: 21 with 50% or greater diameter narrowing of 1 or more left coronary arteries (group I) and 4 with less than 50% diameter reduction of a left coronary artery (group II). No changes occurred in group II. In group I, krypton-81m perfusion decreased progressively in all areas with more than 70% diameter narrowing, with a simultaneous increase in normal regions. At the end of pacing during angina, krypton-81m perfusion was reduced to 81 +/- 4% of control in areas with 71 to 90% diameter reduction (n = 8) and to 69 +/- 6% in areas with more than 90% diameter narrowing (n = 15). In contrast, in regions with 50 to 70% diameter reduction changes were variable (decrease in 4 regions, increase in 2 and an unchanged distribution in 1 region). Krypton-81m perfusion decreased early, before general signs of ischemia in areas with more than 90% diameter reduction, whereas this decrease occurred later in regions with 71 to 90% diameter narrowing, concurrently with ST-segment changes but before anginal pain. Although all signs of ischemia had disappeared between 2 and 5 minutes after pacing, changes in krypton-81m distribution persisted in most areas for 5 to 15 minutes after pacing. It is concluded that the functional significance of coronary arterial narrowing can be assessed with a continuous intracoronary infusion of krypton-81m. Changes in regional distribution persisted after cessation of pacing-induced ischemia, indicating an ongoing decrease in regional myocardial blood flow

Etude du transfert thermique entre un jet rond turbulent et une paroi ...

African Journals Online (AJOL)

Dans ce travail, on s\\'intéresse à l\\'étude du transfert de chaleur d\\'une plaque plane soumise à l\\'action d\\'un jet d\\'air perpendiculaire. L\\'étude de la possibilité d\\'améliorer le transfert de chaleur est effectuée en fonction des paramètres caractéristiques de l\\'interaction jet - paroi. Le problème du jet rond turbulent frappant ...

Kilo-electron-volt neutron capture cross sections of the krypton isotopes

International Nuclear Information System (INIS)

Walter, G.; Leugers, B.; Kappeler; Bao, Z.Y.; Reffo, G.; Fabbri, F.

1986-01-01

The neutron capture cross sections of the stable krypton isotopes were determined in the energy interval from 4 to 250 keV using a C/sub 6/D/sub 6/-detector system in conjunction with the time-of-flight technique. The energy resolution of the measurement was 4% at 20 keV and 6% at 100 keV, and the experimental uncertainties were typically 6 to 10%. The measurements were complemented by statistical model calculations of all krypton isotopes in the mass range 78 < A < 86 to also obtain reliable cross sections for the unstable nuclei /sup 79,81,85/Kr. These calculations were based on local systematics for all relevant parameters, and the results were estimated to show uncertainties of 20 to 25%. Maxwellian average cross sections were calculated for kT=30 keV

Preferential site occupancy observed in coexpanded argon-krypton clusters

International Nuclear Information System (INIS)

Lundwall, M.; Bergersen, H.; Lindblad, A.; Oehrwall, G.; Svensson, S.; Bjoerneholm, O.; Tchaplyguine, M.

2006-01-01

Free heterogeneous argon-krypton clusters have been produced by coexpansion and investigated by means of x-ray photoelectron spectroscopy. By examining cluster surface and bulk binding energy shifts, relative intensities, and peak widths, we show that in the mixed argon-krypton clusters the krypton atoms favor the bulk and argon atoms are pushed to the surface. Furthermore, we show that krypton atoms in the surface layer occupy high-coordination sites and that heterogeneous argon-krypton clusters produced by coexpansion show the same surface structure as argon host clusters doped with krypton. These observations are supported by site-dependent calculations of chemical shifts

Alternative processes for the long-term storage of Kr-85

International Nuclear Information System (INIS)

Penzhorn, R.D.

1977-12-01

The forseeable problems which are characteristic of the long-term storage of Kr-85, are discussed on the basis of the chemical, physical and radiological properties of the fission noble gases krypton and xenon as well as rubidium, the daughter nuclide of Kr-85. The various alternatives suggested in the literature for the long-term storage of Kr-85 are reviewed. The technological realization of each of the proposed alternatives is analyzed. (orig.) [de

Investigation of the interaction of 85Kr with plants in model experiments

International Nuclear Information System (INIS)

Butkus, D.V.; Morkunas, G.S.; Bluvshtejn, D.Yu.; Styro, B.I.

1988-01-01

The method of investigation of the interaction of 85 Kr with plants is described using model experiments and data analysis. The dependencies of the coefficient of 85 Kr absorption by plants on the biological structure of the plant, the concentration of krypton-85 in the environment, the method of plant exposition in the environment with the 85 Kr admixture are provided. The time dependencies of 85 Kr desorption from plants are given. 4 refs.; 7 figs.; 3 tabs

Krypton tagging velocimetry of an underexpanded jet.

Science.gov (United States)

Parziale, N J; Smith, M S; Marineau, E C

2015-06-01

In this work, we present the excitation/emission strategy, experimental setup, and results of an implementation of krypton tagging velocimetry (KTV). KTV is performed as follows: (i) seed a base flow with krypton; (ii) photosynthesize metastable krypton atoms with a frequency-doubled dye laser to form the tagged tracer; (iii) record the translation of the tagged metastable krypton by imaging the laser-induced fluorescence (LIF) that is produced with an additional dye laser. The principle strength of KTV, relative to other tagging velocimetry techniques, is the use of a chemically inert tracer. KTV results are presented for an underexpanded jet of three mixtures of varying Kr/N2 concentration. It is demonstrated that KTV can be used in gas mixtures of relatively low krypton mole fraction (0.5% Kr/99.5% N2), and the KTV data from that experiment are found to be in good agreement with an empirical fit found in the literature. We find that KTV is useful to perform instantaneous velocity measurements with metastable krypton as a chemically inert, dilute, long-lifetime tracer in gas-phase flows.

Immobilisation of krypton in a metallic matrix by combined ion implantation and sputtering

International Nuclear Information System (INIS)

Whitmell, D.S.

1980-01-01

With the increase in nuclear power, it may be necessary to contain for 100 to 200 years the radioactive 85 krypton released during fuel reprocessing. The ideal method of immobilising radioactive materials is in the form of stable, monolithic solids which are resistant to the effects of the environment or accidents, and which can retain the radioactivity under all envisaged conditions. Since krypton is a rare gas, not forming thermally stable compounds, conventional methods of storage are not possible. A process is being developed to immobilise the krypton in the form of small gas bubbles in a metal matrix by implanting the gas into a metal layer from a glow discharge and then burying the implanted layer by sputter deposition. By repeating the process, a thick layer of deposit is built up with the krypton dispersed throughout the matrix as bubbles of diameter less than 20 A. This process offers an ideal form of storage since gas in bubbles is not thermally released until the temperature of the matrix is close to the melting point, and also leakage of gas by corrosion or mechanical damage will be small. A pilot plant is being built in order to demonstrate the process on a scale comparable with that required for a reprocessing plant. The efficiency of the process is dependent upon the amount of gas which can be implanted at low energy into a thin layer and its subsequent retention. More information is required on the processes occurring when krypton ions are implanted close to the surface, in particular, the retention and re-emission of the gas, and the formation of clusters and bubbles. (author)

Removing krypton from xenon by cryogenic distillation to the ppq level

Science.gov (United States)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; Di Gangi, P.; Di Giovanni, A.; Diglio, S.; Duchovni, E.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Franco, D.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Huhmann, C.; Itay, R.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Calloch, M. Le; Lin, Q.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Undagoitia, T. Marrodán; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Meng, Y.; Messina, M.; Micheneau, K.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orrigo, S. E. A.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Piro, M.-C.; Pizzella, V.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Saldanha, R.; Santos, J. M. F. dos; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Lavina, L. Scotto; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. v.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Upole, N.; Wang, H.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Cristescu, I.

2017-05-01

The XENON1T experiment aims for the direct detection of dark matter in a detector filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the β -emitter ^{85}Kr which is present in the xenon. For XENON1T a concentration of natural krypton in xenon ^{nat}Kr/Xe McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4\\cdot 10^5 with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of ^{nat}Kr/Xe<26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN.

Development of long term storage technique for recovered Kr-85, (1)

International Nuclear Information System (INIS)

Inada, Eiichi; Motoyama, Shigeji; Tsunoda, Naomi; Yamamoto, Keizo; Hirano, Seiji.

1979-01-01

The adsorption storage method of radioactive krypton Kr-85 using a double cylinder packed with activated charcoal is expected to be put into practical use as an intermediate storing method until the immobilization technique for long term storage is established. In this paper, the conceptual design of an intermediate, remote-controlled Kr-85 storage facility is presented. The features of this system are double containment, low pressure storage, and remote control. Kr-85 is at first filled into a double cylinder by the adsorbing effect of activated charcoal at low temperature (-196 deg C) by cooling with liquid nitrogen. Then, the unwelded portion of the outer cylinder containing the inner cylinder is welded and inspected to make double containment. The double cylinders are cooled by ventilation to remove the decay heat of Kr-85, and krypton leakage is always monitored. If any leakage is detected, the double cylinder is transferred to the cutting cell for the re-encapsulation of Kr-85 in a safe double cylinder. All operations are performed by remote control because of a high radiation field. The expected amount and composition of Kr-85 to be recovered from the reprocessing plant are also given as the design conditions. (Wakatsuki, Y.)

Separation of the fission product noble gases krypton and xenon from dissolver off-gas in reprocessing HTGR-fuel

Energy Technology Data Exchange (ETDEWEB)

Bohnenstingl, J.; Djoa, S. H.; Laser, M.; Mastera, S.; Merz, E.; Morschl, P.

1976-04-15

This paper describes a process developed for the retainment and separation of volatile (³H, ^{129 +131}I) and gaseous (⁸⁵Kr, Xe) fission products from the off-gas produced during dissolution of HTGR-fuel. To prevent unnecessary dilution of liberated noble gases by surrounding atmosphere, a helium purge-gas cycle is applied to enable a coarse fractionating of krypton and xenon by cold-trapping at about 80 deg K after precleaning the gas stream. The process consists of the following steps: deposition of droplets and solid aerosols; chemisorption of iodine on silver impregnated silica gel; catalytic removal of nitrogen oxides and oxygen; drying of the process gas stream; final filtering of abraded solids; deposition of xenon in solid form at 80 deg K and low subpressure; deposition of krypton in solid form at 80 deg K after compression to about 6 bar; decontamination of ⁸⁵krypton-containing xenon by batch distillation for eventual industrial utilization; and removal of nitrogen and argon enrichment during continuous operation in the purge-gas stream by inleaking air with charcoal. A continuously operating dissolver vessel, closed to the surrounding atmosphere, yields a very high content of noble gases, e.g., 0.35 vol % krypton and 2.0 vol % xenon. The presented off-gas treatment unit is operated in cold runs with 1/3 of the full capacity and can treat about 1 m³ STP/h helium, corresponding to a quantity of about 10,000 MW(e) HTGR-fuel reprocessing plant.

Immobilization of krypton in a metallic matrix by combined ion implantation and sputtering

International Nuclear Information System (INIS)

Whitmell, D.S.

1980-01-01

With the increase in nuclear power, it may be necessary to contain for 100 to 200 years the radioactive 85 krypton released during fuel reprocessing. The ideal method of immobilizing radioactive materials is in the form of stable, monolithic solids which are resistant to the effects of the environment or accidents, and which can retain the radioactivity under all envisaged conditions. Since krypton is a rare gas, not forming thermally stable compounds, conventional methods of storage are not possible. A process is being developed to immobilize the krypton in the form of small gas bubbles in a metal matrix by implanting the gas into a metal layer from a glow discharge and then burying the implanted layer by sputter deposition. By repeating the process, a thick layer of deposit is built up with the krypton dispersed throughout the matrix as bubbles of diameter less than 20 A. This process offers an ideal form of storage since gas in bubbles is not thermally released until the temperature of the matrix is close to the melting point, and also leakage of gas by corrosion or mechanical damage will be small. A pilot plant is being built in order to demonstrate the process on a scale comparable with that required for a reprocessing plant. The efficiency of the process is dependent upon the amount of gas which can be implanted at low energy into a thin layer and its subsequent retention. (author)

Immobilization technology for krypton in amorphous zeolite

International Nuclear Information System (INIS)

Takusagawa, Atsushi; Ishiyama, Keiichi

1989-01-01

Radioactive krypton recovered from the offgas of a reprocessing plant requires long-term storage on the order of 100 years. Immobilization technology for krypton into amorphous zeolite 5A is considered one of the best methods for long-term storage. In this report, conditions for immobilization treatment and stability of amorphous zeolite 5A loaded krypton against heat, radiation and water are discussed, and a treatment system using this technology is described. (author)

Ionization relaxation in shock-heated krypton-argon mixtures

International Nuclear Information System (INIS)

Ezumi, Hiromichi; Kawamura, Masahiko; Yokota, Toshiaki.

1977-01-01

The ionization relaxation processes behind shock waves in pure krypton and krypton-argon mixtures have been investigated using a Mach-Zehnder interferometer technique. The incident shock velocity was fixed in the neighborhood of Us=2800 m/sec, and the initial pressure was fixed at 0.95 Torr. The experimental results were compared with theoretical values based on the two-step collisional ionization model taking into account of the wall boundary-layer effect. The slope constants of excitation cross section against relative kinetic energy between krypton atom-atom collisions, krypton atom-electron collisions, and krypton-argon atom-atom collisions were determined to be 4.2 x 10 -19 cm 2 /eV, 1.2 x 10 -17 cm 2 /eV, and 4.2 x 10 -19 cm 2 /eV, respectively. (auth.)

Solubility of krypton in hydrofracture grout at elevated pressures

International Nuclear Information System (INIS)

Fitzgerald, C.L.; Mailen, J.C.

1982-01-01

The solubilities of krypton in water, simulated waste solution, and simulated grout at about 25 0 C and to pressures of 150 atm have been determined. The results of these studies show that preliminary calculations of krypton solubility based on the aqueous component of the hydrofracture grout were overly pessimistic. The volume of noble gas generated annually by the reference reprocessing plant would be soluble in the annual hydrofracture grout injection at ORNL at about 10 atm. The amount of krypton in the gas phase would depend on the amount of air in the hydrofracture grout mixture. At 34 atm, and with a small air volume relative to the injected krypton, the krypton would constitute about 30% of the gas bubbles. The disposal of krypton via injection with hydrofracture grout seems to be a viable process. The next logical steps would be to determine the krypton diffusion rate at injection conditions, and possibly to perform a test injection. At present, the schedule for future work is uncertain since funds for this project have been reduced significantly

Photon W value for krypton in the M-shell transition region.

Science.gov (United States)

Saito, N; Suzuki, I H

2001-09-01

Absolute W values for krypton have been measured for incident X rays with energies in the range of 85 to 1000 eV, using monochromatic synchrotron radiation and a multiple-electrode ion chamber technique that yields the absolute intensity of the X-ray beam and the photoabsorption cross section. To improve the purity of the incident X rays, the electron storage ring was operated at an energy lower than the normal mode, and thin filters were used. The W values are derived from the measured photon intensity and photoabsorption cross section, using the mean charges of the residual ions obtained in previous work. A considerable oscillation of the W values with the photon energy was found in the region near the krypton 3d electron ionization edge. The results are discussed and compared with data in the literature for low-energy electrons and with the calculations from a model that includes multiple photoionization effects related to inner-shell ionization.

An evaluation of krypton propellant in Hall thrusters

Science.gov (United States)

Linnell, Jesse Allen

Due to its high specific impulse and low price, krypton has long sparked interest as an alternate Hall thruster propellant. Unfortunately at the moment, krypton's relatively poor performance precludes it as a legitimate option. This thesis presents a detailed investigation into krypton operation in Hall thrusters. These findings suggest that the performance gap can be decreased to 4% and krypton can finally become a realistic propellant option. Although krypton has demonstrated superior specific impulse, the xenon-krypton absolute efficiency gap ranges between 2 and 15%. A phenomenological performance model indicates that the main contributors to the efficiency gap are propellant utilization and beam divergence. Propellant utilization and beam divergence have relative efficiency deficits of 5 and 8%, respectively. A detailed characterization of internal phenomena is conducted to better understand the xenon-krypton efficiency gap. Krypton's large beam divergence is found to be related to a defocusing equipotential structure and a weaker magnetic field topology. Ionization processes are shown to be linked to the Hall current, the magnetic mirror topology, and the perpendicular gradient of the magnetic field. Several thruster design and operational suggestions are made to optimize krypton efficiency. Krypton performance is optimized for discharge voltages above 500 V and flow rates corresponding to an a greater than 0.015 mg/(mm-s), where alpha is a function of flow rate and discharge channel dimensions (alpha = m˙alphab/Ach). Performance can be further improved by increasing channel length or decreasing channel width for a given flow rate. Also, several magnetic field design suggestions are made to enhance ionization and beam focusing. Several findings are presented that improve the understanding of general Hall thruster physics. Excellent agreement is shown between equipotential lines and magnetic field lines. The trim coil is shown to enhance beam focusing

All-optical atom trap trace analysis for rare krypton isotopes

Energy Technology Data Exchange (ETDEWEB)

Woelk, Pablo; Kohler, Markus; Sieveke, Carsten; Hebel, Simon; Sahling, Peter [Carl Friedrich von Weizsaecker Centre for Science and Peace Research, University of Hamburg (Germany); Becker, Christoph; Sengstock, Klaus [Institut fuer Laser-Physik, University of Hamburg (Germany)

2016-07-01

The isotope Krypton-85 is an excellent indicator for the detection of nuclear reprocessing activities. However, for the analysis of atmospheric air samples, sensitive measuring methods down to the single atom level are required because of the small concentrations. Furthermore, for a practical and effective detection of clandestine reprocessing, small sample sizes and a high sample throughput rate are desirable. Established methods using Atom Trap Trace Analysis (ATTA) allow high sensitivity but have a limited throughput of about 200 samples per year, since the vacuum chambers have to be flushed for several hours after each measurement to avoid cross contamination due to the RF-driven excitation of metastable states. Here we present an enhanced ATTA apparatus, which in contrast to the established methods, produces metastable Kr all-optically. This avoids cross contamination, therefore allowing a much higher throughput rate. The apparatus is based on a self-made VUV-lamp and a 2D-3D magneto-optical trap setup. In the 2D trap metastable krypton is produced and a beam of atoms is formed by Doppler-cooling simultaneously.

An interim evaluation of the thermal stability of Cu--Y--85Kr sputter deposits and plans for evantual disposal

International Nuclear Information System (INIS)

McClanahan, E.D.; Bradley, E.R.

1988-04-01

A pilot process was developed and demonstrated for trapping and storing 85 Kr from the dissolver off-gas stream of a nuclear fuel reprocessing plant. Ions produced in a low-pressure krypton discharge are implanted on the inner wall of a krypton trapping storage device (KTSD). Objectives were to measure the release of 85 Kr implanted in a copper--yttrium alloy, outline the characterization work to be performed on the Cu/endash/Y/endash/ 85 Kr waste form, and identify the options available for disposing of the remaining 85 Kr. Release rates were obtained from periodic measurements of the krypton released from both radioactive and nonradioactive krypton-loaded KTSDs. Sampling is expected to continue as long as the extrapolated release rates remain acceptable for a period not to exceed one half-life (/approximately/10 y). Seven tests were performed on a nonradioactive KTSD at 180 to 450/degree/C. Three KTSDs loaded with 80 to 150 Ci of 85 Kr stored at 150, 250, and 350/degree/C were sampled four times each. Proposed post-elevated-temperature storage characterization of the Cu/endash/Y/endash/ 85 Kr waste form is outlined. Both radioactive and nonradioactive test specimens stored below 350/degree/C showed release rates less than 0.1%y/sup /minus/1/. Release rates for the radioactive specimens were obtained for storage periods of 1.6, 1.1, and 0.4 y at 150, 250 and 350/degree/C. The nonradioactive specimen has been held at temperatures between 180 and 450/degree/C, but mainly at 350/degree/C for a total storage time of 2.1 y. Tests should continue for a period not exceeding 10 y, and then the remaining Cu/endash/Y/endash/ 85 Kr waste form should be evaluated to better predict the overall stability. Three options for the disposal of the remaining 85 Kr. 3 refs., 2 figs., 2 tabs

Treatment of Proliferative Diabetic Retinopathy: a Comparison of Krypton Green, Krypton Yellow and Krypton Red Lasers%三种波长氪离子激光治疗增殖期糖尿病性视网膜病变的疗效比较

Institute of Scientific and Technical Information of China (English)

王洁; 李军; 韩素珍

2011-01-01

目的 比较氪绿激光、氪黄激光和氪红激光治疗增殖期糖尿病性视网膜病变(PDR)的疗效.方法 PDR患者167例243只眼,随机分为氪绿激光、氪黄激光和氪红激光治疗组,行标准全视网膜光凝.比较三组患眼视力、新生血管的变化.结果 三组患者视力比较差异无显著意义(P>0.05).新生血管消退比较,氪绿激光组与氪红激光组比较差异无显著意义(P>0.05).氪黄激光组与氪绿激光组、氪红激光组比较差异有显著意义(P<0.05).结论 氪绿激光、氪黄激光和氪红激光对PDR均有治疗作用,氪绿激光和氪红激光的疗效较好.%Objective To investigate the therapeutic effect of the krypton green, krypton yellow or krypton red laser in the treatnent of proliferative diabetic retinopathy(PDR) .Methods Two hundred and forty-three eyes of 167 PDR patients were assigned randomly to receive either krypton green, krypton yellow or krypton red laser treatment, to investigate the changes in the vision and neovessels.Results There was no statistical difference among krypton green, krypton yellow and krypton red laser treatment for PDR(P＞0. 05)in visual improvement, and also between krypton green with krypton red laser in neovessels loss, but there was statistical difference between krypton yellow with krypton green or krypton red laser in it.Conclusions The three kinds of krypton lasers all have therapeutic effect on PDR, but the krypton green and krypton red lasers should be preferred.

Liquid--vapor isotope fractionation factors in argon--krypton binary mixtures

International Nuclear Information System (INIS)

Lee, M.W.; Neufeld, P.; Bigeleisen, J.

1977-01-01

An equilibrium isotope effect has been studied as a continuous function of the potential field acting on the atom undergoing isotopic exchange. This has been accomplished through a study of the liquid vapor isotope fractionation factors for both, 36 Ar/ 40 Ar and 80 Kr/ 84 Kr in a series of binary mixtures which span the range between the pure components at 117.5 0 K. The 36 Ar/ 40 Ar fractionation factor increases (linearly) from (lnα)2.49 x 10 -3 in pure liquid argon to 2.91 x 10 -3 in an infinitely dilute solution in liquid krypton. Conversely, the 80 Kr/ 84 Kr fractionation factor decreases (linearly) from (lnα)0.98 x 10 -3 in pure liquid krypton to 0.64 x 10 -3 in an infinetely dilute solution in pure liquid argon. The mean force constants 2 U>/sub c/ on both argon and krypton atoms in the mixtures are derived from the respective isotope fractionation factors.The mean force constants for argon and krypton as a function of composition have been calculated by a modified corresponding states theory which uses the pure liquids as input parameters. The discrepancy is 8 percent at X/sub Ar/ + O. A systematic set of calculations has been made of 2 U> (Ar) and 2 U> (Kr) as a function of composition using radial distribution functions generated by the Weeks--Chandler--Anderson perturbation theory

Gauging in volumetric activity of the L.B.123 in order to study release dispersion in 85Kr

International Nuclear Information System (INIS)

Label, D.

2001-01-01

The L.B.123 is a krypton detector. The calculations of the different beta and gamma yields have allowed to confirm that the LB123 is low sensitive to gamma radiations and in the case of krypton 85 the only beta contribution is to be considered. This detector can be used to study the dispersion modes of gaseous releases in the environment of La Hague. (N.C.)

Ventilation studies of the lung with krypton-81m

International Nuclear Information System (INIS)

Klopper, J.F.; Baard, W.P.; Van Heerden, P.D.R.

1981-01-01

During a 2-year study period it was found that krypton-81m was useful in clinical practice. During this period 1563 technetium-99m perfusion studies and 807 krypton-81m ventilation studies were performed. A distinct advantage of krypton-81m was the ease with which multiple views could be obtained. These views could be directly compared with those of preceding perfusion studies. However, interruptions in the regular supply of rubidium-81/krypton-81m generators affected 17,1% of perfusion studies and xenon-127 should be a suitable substitute for these periods

Electron impact excitation of autoionising states of krypton

Science.gov (United States)

Srivastava, S. K.; Trajmar, S.

1978-01-01

Energy-loss spectra of krypton in the region between 21 and 29 eV have been obtained at electron impact energies of 30, 60 and 100 eV. For each energy, the angular distribution of intensities has been measured at 5, 10 and 15 deg scattering angles. Assignments of spectral features found in this region are suggested and a comparison is made with previous measurements.

Services de transfert des savoirs

Directory of Open Access Journals (Sweden)

Albert Simard

2009-03-01

Full Text Available Le présent article décrit un modèle visant à faciliter la compréhension du processus de transfert du contenu depuis sa source jusqu’à son utilisation. Un groupe de travail de Ressources naturelles Canada a étudié la nature du transfert des savoirs à l’aide d’un modèle de services, afin de découvrir et comprendre les modèles et processus sous-jacents. Les services de savoir sont des programmes qui créent et fournissent des produits organisationnels basés sur un contenu et ayant une valeur intégrée. Ces programmes sont destinés à être utilisés en interne ou transférés pour répondre aux souhaits et besoins d’un utilisateur externe. Les critères de conception du modèle sont les suivants : indépendance par rapport au contenu, concentration sur l’organisation, évolutivité, deux pilotes et deux niveaux de résolution. Le modèle est basé sur une chaîne de valeur dans laquelle la valeur est intégrée, déplacée ou extraite. Un système de services de savoir se divise en neuf étapes : générer, transformer, gérer, utiliser en interne, transférer, ajouter de la valeur, utiliser professionnellement, utiliser personnellement et évaluer. Les services de savoir sont fournis par l’intermédiaire d’un spectre de distribution allant de complexe à accessible. À chaque région du spectre de distribution correspond une série d’attributs qui influencent la manière dont les services sont fournis.This paper describes a model intended to increase understanding of how content is transferred from its source to its use. A Natural Resources Canada task group explored the nature of knowledge transfer with a services paradigm to discover and understand underlying patterns and processes. Knowledge Services are programs that produce and pro-vide content-based organizational outputs with embedded value that are intended to be used internally or transferred to meet external user wants or needs. Model design criteria

Formation of actinide hexafluorides at ambient temperatures with krypton difluoride

International Nuclear Information System (INIS)

Asprey, L.B.; Eller, P.G.; Kinkead, S.A.

1986-01-01

A second low-temperature agent, krypton difluoride, for generating volatile plutonium hexafluoride is reported (dioxygen difluoride is the only other reported agent). Plutonium hexafluoride is formed at ambient or lower temperature by the treatment of various solid substrates with krypton difluoride. Volatilization of uranium and neptunium from solid substrates using gaseous krypton difluoride is also reported for the first time. The formation of actinide hexafluorides has been confirmed for the reaction of krypton difluoride in anhydrous HF with UO 2 and with uranium and neptunium fluorides at ambient temperatures. Treatment of americium dioxide with krypton difluoride did not yield americium hexafluoride under the conditions studied. 15 references, 2 figures

Method of determining paper-deposited materials, eg. lead, by their reaction with radioactive krypton

International Nuclear Information System (INIS)

Tolgyessy, J.; Pruzinec, J.

1976-01-01

The invention claims a method of determining substances on a paper carrier based on the substance reaction with 85 Kr gas and the measurement of radioactivity of the kryptonate formed. Lead is shown as an example. Different amounts of lead acetate were deposited on Whatman 2 chromatographic paper as was an unknown sample of Pb salt. The paper was exposed to a 2.5 mCi 85 Kr atmosphere for 48 hours. The activity of the individual spots was then measured, a calibration curve established and the amount of lead in the analyzed sample read-out. (Ha)

The atmosphere of Mars - Detection of krypton and xenon

Science.gov (United States)

Owen, T.; Biemann, K.; Biller, J. E.; Lafleur, A. L.; Rushneck, D. R.; Howarth, D. W.

1976-01-01

Krypton and xenon have been discovered in the Martian atmosphere with the mass spectrometer on the second Viking lander. Krypton is more abundant than xenon. The relative abundances of the krypton isotopes appear normal, but the ratio of xenon-129 to xenon-132 is enhanced on Mars relative to the terrestrial value for this ratio. Some possible implications of these findings are discussed.

Krypton-85 health risk assessment for a nuclear fuel reprocessing plant

International Nuclear Information System (INIS)

Mellinger, P.J.; Brackenbush, L.W.; Tanner, J.E.; Gilbert, E.S.

1984-08-01

The risks involved in the routine release of 85 Kr from nuclear fuel reprocessing operations to the environment were compared to those resulting from the capture and storage of 85 Kr. Instead of releasing the 85 Kr to the environment when fuel is reprocessed, it can be captured, immobilized and stored. Two alternative methods of capturing 85 Kr (cryogenic distillation and fluorocarbon absorption) and one method of immobilizing the captured gas (ion implantation/sputtering) were theoretically incorporated into a representative fuel reprocessing plant, the Barnwell Nuclear Fuel Plant, even though there are no known plans to start up this facility. Given the uncertainties in the models used to generate lifetime risk numbers (0.02 to 0.027 radiation induced fatal cancers expected in the occupational workforce and 0.017 fatal cancers in the general population), the differences in total risks for the three situations, (i.e., no-capture and two-capture alternatives) cannot be considered meaningful. It is possible that no risks would occur from any of the three situations. There is certainly no reason to conclude that risks from 85 Kr routinely released to the environment are greater than those that would result from the other two situations considered. Present regulations mandate recovery and disposal of 85 Kr from the off gases of a facility reprocessing spent fuel from commercial sources. Because of the lack of a clear-cut indication that recovery woud be beneficial, it does not seem prudent to burden the facilities with a requirement for 85 Kr recovery, at least until operating experience demonstrates the incentive. The probable high aging of the early fuel to be processed and the higher dose resulting from the release of the unregulated 3 H and 14 C also encourage delaying implementation of the 85 Kr recovery in the early plants

Removing krypton from xenon by cryogenic distillation to the ppq level

Energy Technology Data Exchange (ETDEWEB)

Aprile, E.; Anthony, M.; De Perio, P.; Gao, F.; Goetzke, L.W.; Greene, Z.; Messina, M.; Plante, G.; Rizzo, A.; Zhang, Y. [Columbia University, Physics Department, New York, NY (United States); Aalbers, J.; Breur, P.A.; Brown, A.; Colijn, A.P.; Decowski, M.P.; Hogenbirk, E.; Tiseni, A. [Nikhef and the University of Amsterdam, Science Park, Amsterdam (Netherlands); Agostini, F. [INFN-Laboratori Nazionali del Gran Sasso (Italy); Gran Sasso Science Institute, L' Aquila (Italy); University of Bologna, Department of Physics and Astrophysics, Bologna (Italy); INFN-Bologna (Italy); Alfonsi, M.; Geis, C.; Grignon, C.; Oberlack, U.; Scheibelhut, M.; Schindler, S. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Amaro, F.D.; Cardoso, J.M.R.; Lopes, J.A.M.; Orrigo, S.E.A.; Santos, J.M.F. dos; Silva, M. [University of Coimbra, Department of Physics, Coimbra (Portugal); Arneodo, F.; Benabderrahmane, M.L.; Di Giovanni, A.; Maris, I. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Barrow, P.; Baudis, L.; Franco, D.; Galloway, M.; Kessler, G.; Kish, A.; Mayani, D.; Pakarha, P.; Piastra, F.; Wei, Y.; Wulf, J. [Physik-Institut, University of Zurich, Zurich (Switzerland); Bauermeister, B. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Stockholm University, AlbaNova, Oskar Klein Centre, Department of Physics, Stockholm (Sweden); Berger, T.; Brown, E.; Piro, M.C. [Rensselaer Polytechnic Institute, Department of Physics, Applied Physics and Astronomy, Troy, NY (United States); Bruenner, S.; Cichon, D.; Eurin, G.; Hasterok, C.; Lindemann, S.; Lindner, M.; Undagoitia, T.M.; Pizzella, V.; Rauch, L.; Rupp, N.; Schreiner, J.; Simgen, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Bruno, G.; Gallo Rosso, A.; Molinario, A. [INFN-Laboratori Nazionali del Gran Sasso (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Budnik, R.; Duchovni, E.; Itay, R.; Landsman, H.; Lellouch, D.; Levinson, L.; Manfredini, A.; Priel, N. [Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel); Buetikofer, L.; Coderre, D.; Kaminsky, B.; Schumann, M.; Sivers, M. v. [Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); Calven, J.; Conrad, J.; Ferella, A.D.; Pelssers, B. [Stockholm University, AlbaNova, Oskar Klein Centre, Department of Physics, Stockholm (Sweden); Cervantes, M.; Lang, R.F.; Masson, D.; Pienaar, J.; Reichard, S.; Reuter, C. [Purdue University, Department of Physics and Astronomy, West Lafayette, IN (United States); Cussonneau, J.P.; Diglio, S.; Le Calloch, M.; Masbou, J.; Micheneau, K.; Persiani, R.; Thers, D. [Universite de Nantes, SUBATECH, Ecole des Mines de Nantes, CNRS/In2p3, Nantes (France); Di Gangi, P.; Garbini, M.; Massoli, F.V.; Sartorelli, G.; Selvi, M. [University of Bologna, Department of Physics and Astrophysics, Bologna (Italy); INFN-Bologna (Italy); Fei, J.; Ni, K.; Ye, J. [University of California, Department of Physics, San Diego, CA (United States); Fieguth, A.; Huhmann, C.; Murra, M.; Rosendahl, S.; Weinheimer, C. [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Fulgione, W. [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L' Aquila (Italy); INFN-Torino (Italy); Osservatorio Astrofisico di Torino, Torino (Italy); Grandi, L.; Saldanha, R.; Shockley, E.; Upole, N. [University of Chicago, Department of Physics and Kavli Institute of Cosmological Physics, Chicago, IL (United States); Lin, Q. [Laboratori Nazionali del Gran Sasso, Assergi (Italy); Meng, Y.; Stein, A.; Wang, H. [University of California, Physics and Astronomy Department, Los Angeles, CA (United States); Miguez, B.; Trinchero, G. [INFN-Torino (Italy); Osservatorio Astrofisico di Torino, Torino (Italy); Naganoma, J.; Shagin, P. [Rice University, Department of Physics and Astronomy, Houston, TX (United States); Lavina, L.S. [LPNHE, Universite Pierre et Marie Curie, Universite Paris Diderot, CNRS/IN2P3, Paris (France); Tunnell, C. [Nikhef and the University of Amsterdam, Science Park, Amsterdam (Netherlands); University of Chicago, Department of Physics and Kavli Institute of Cosmological Physics, Chicago, IL (United States); Cristescu, I. [Karlsruhe Institute of Technology, Tritium Laboratory Karlsruhe, Eggenstein-Leopoldshafen (Germany); Collaboration: XENON Collaboration

2017-05-15

The XENON1T experiment aims for the direct detection of dark matter in a detector filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the β-emitter {sup 85}Kr which is present in the xenon. For XENON1T a concentration of natural krypton in xenon {sup nat}Kr/Xe < 200 ppq (parts per quadrillion, 1 ppq = 10{sup -15} mol/mol) is required. In this work, the design, construction and test of a novel cryogenic distillation column using the common McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4 . 10{sup 5} with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of {sup nat}Kr/Xe < 26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN. (orig.)

Applications developed for byproduct 85Kr and tritium

International Nuclear Information System (INIS)

Remini, W.C.; Case, F.N.; Haff, K.W.; Tiegs, S.M.

1983-01-01

The radionuclides, krypton-85 and tritium, both of which are gases under ordinary conditions, are used in many applications in industries and by the military forces. Krypton-85 is produced during the fissioning of uranium and is released during the dissolution of spent-fuel elements. It is a chemically inert gas that emits 0.695-MeV beta rays and a small yield of 0.54-MeV gammas over a half life of 10.3 years. Much of the 85 Kr currently produced is released to the atmosphere; however, large-scale reprocessing of fuel will require collection of the gas and storage as a waste product. An alternative to storage is utilization, and since the chemical and radiation characteristics of 85 Kr make this radionuclide a relatively low hazard from the standpoint of contamination and biological significance, a number of uses have been developed. Tritium is produced as a byproduct of the nuclear-weapons program, and it has a half life of 12.33 years. It has a 0.01861-MeV beta emission and no gamma emission. The absence of a gamma-ray energy eliminates the need for external shielding of the devices utilizing tritium, thus making them easily transportable. Many of the applications require only small quantities of 85 Kr or tritium; however, these uses are important to the technology base of the nation. A significant development that has the potential for beneficial utilization of large quantities of 85 Kr and of tritium involves their use in the production of low-level lighting devices. Since these lights are free from external fuel supplies, have a long half life (> 10 years), are maintenance-free, reliable, and easily deployed, both military and civilian airfield-lighting applications are being studied

Krypton Ion Thruster Performance

Science.gov (United States)

Patterson, Michael J.; Williams, George J.

1992-01-01

Preliminary data were obtained from a 30 cm ion thruster operating on krypton propellant over the input power range of 0.4 to 5.5 kW. The data presented are compared and contrasted to the data obtained with xenon propellant over the same input power envelope. Typical krypton thruster efficiency was 70 percent at a specific impulse of approximately 5000 s, with a maximum demonstrated thrust to power ratio of approximately 42 mN/kW at 2090 s specific impulse and 1580 watts input power. Critical thruster performance and component lifetime issues were evaluated. Order of magnitude power throttling was demonstrated using a simplified power-throttling strategy.

Development of Atmospheric Air 85Kr Monitoring Methodology on the Territory of the USSR

Science.gov (United States)

Pakhomov, Sergei; Dubasov, Yury

2014-05-01

Highly sensitive, low-background and high-performance method of beta-radioactivity measurements of the gas samples was developed in mid-eighties at Khlopin Radium institute. This method was based on the use of the serial automated installation for liquid scintillation measurements and special scintillating cells. Cells were equipped with the gas valve, and their internal surface were covered by a thin layer of organic scintillator. This method found was successfully was applied for 85Kr activity measurements in atmospheric krypton samples and for 85Kr concentration measurements in atmospheric air. For the first time, method developed for 85Kr activity measurements, was practically tested in May - June, 1986, while studying radioactive pollution characteristics in the air basin of Russia and Ukraine after the Chernobyl NPP accident. Thus for sampling of atmospheric krypton the industrial krypton-xenon mix manufactured at air-separating plants, located in the cities of Cherepovets, Lipetsk, Krivoi Rog and Enakiyevo was used. In the end of April and in the first half of May it was determined that 1,5-fold excess concentrations of 85Kr in atmospheric air were observed in atmospheric air of considerable part of the European territory of Russia and Ukraine During the period from 1987 to 1991 this method was used for monitoring of 85Kr on the territory of the former USSR in the air basin of Russia, Ukraine and Kazakhstan. Industrial krypton-xenon mix manufactured at 14 large air-separating plants was also used for sampling. Six of them were situated in Russia (Novomoskovsk, Lipetsk, Cherepovets, Chelyabinsk, Nizhni Tagil, Orsk). Seven - in Ukraine (Enakiyevo, Kommunarsk, Krivoi Rog, Makeyevka, Mariupol, Severodonetsk, Dneprodzerzhinsk). One plant was situated in Temirtau, in Kazakhstan. The analysis indicated that in Krivoi Rog; Dneprozhzerzhinsk; Severodonetsk; Makeyevka; Mariupol; Enakiyevo; Kommunarsk; Novomoskovsk and Cherepovets the average 85Kr concentration in

Separation of krypton from carbon dioxide and oxygen with molecular sieves

International Nuclear Information System (INIS)

Forsberg, C.W.

1976-01-01

Molecular sieves were investigated to separate 1 percent mixtures of krypton in gas streams of a few percent oxygen and 90+ percent carbon dioxide. Such a system will be required to concentrate the krypton gas between radioactive krypton off-gas cleanup systems such as KALC (Krypton Absorption in Liquid Carbon Dioxide) and any krypton gas bottling station. Linde 5A molecular sieves were found capable of selectively removing the CO 2 from the gas stream while partially separating the oxygen from the krypton; i.e., effecting a three-component gas separation. This use of molecular sieves differs from standard practice in two respects. First, the bulk of the gas (greater than 90 percent) is removed by molecular sieves rather than the normal practice of using molecular sieves to remove trace impurities. Second, in a single bed two separations occur simultaneously, CO 2 from other gases and krypton from oxygen. The use of molecular sieves for separating krypton and carbon dioxide is superior to alternatives such as CO 2 freezeout and chemical traps when there are only moderate gas flows and there is a need for very high reliability and ease of maintenance

Dynamique institutionnelle des transferts de gestion dans le corridor ...

African Journals Online (AJOL)

Ten years after their creation, the operation of the community-based natural resource management policy named 'transfert de gestion' – the 1996 GELOSE law (applied to any kind of natural resources), and the 2001 GCF decree (only applied to forests) - remains little understood. The forest corridor linking Ranomafana and ...

Determination of low levels of krypton in helium by gas chromatography

International Nuclear Information System (INIS)

Evans, D.L.; Mukherji, A.K.

1980-01-01

Krypton-helium mixture was used as an adsorbate for surface area measurement--. The surface area measurements depend on the accuracy with which the krypton concentration is known. Generally gas tanks supplied by Union Carbide provide a nominal value of 0.1% krypton in helium. The surface area measurements require, however, that the krypton concentraion be known to +- 0.001% or better. A standard plot of krypton volume in microliters vs the area under the curve as measured by a planimeter using the helium detector and Molecular Sieve 5A column was obtained. Results with a thermal conductivity detector using Molecular Sieve 5A and Carbon Molecular Sieve are also given. Low levels of krypton in helium can be measured with precision using either a helium or a thermal conductivity detector with Molecular Sieve 5A or Carbon Molecular Sieve columns. 2 figures, 1 table

Flow Characterization of Vapor Phase of Geothermal Fluid in Pipe Using Isotope 85Kr and Residence Time Distribution Modeling

Directory of Open Access Journals (Sweden)

S. Sugiharto

2014-08-01

Full Text Available Measurement of vapor flow in geothermal pipe faces great challenges due to fast fluids flow in high-temperature and high-pressure environment. In present study the flow rate measurement has been performed to characterization the geothermal vapor flow in a pipe. The experiment was carried out in a pipe which is connected to a geothermal production well, KMJ-14. The pipe has a 10” outside diameter and contains dry vapor at a pressure of 8 kg/cm2 and a temperature of 170 oC. Krypton-85 gas isotope (85Kr has been injected into the pipe. Three collimated radiation detectors positioned respectively at 127, 177 and 227m from injection point were used to obtain experimental data which represent radiotracer residence time distribution (RTD in the pipe. The last detector at the position of 227 m did not respond, which might be due to problems in cable connections. Flow properties calculated using mean residence time (MRT shows that the flow rate of the vapor in pipe is 10.98 m/s, much faster than fluid flow commonly found in various industrial process plants. Best fitting evaluated using dedicated software developed by IAEA expert obtained the Péclet number Pe as 223. This means that the flow of vapor of geothermal fluids in pipe is plug flow in character. The molecular diffusion coefficient is 0.45 m2/s, calculated from the axial dispersion model.

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1981-08-01

Over a dozen prospective adsorbents for krypton were studied and evaluated with respect to adsorption capacity and cost for dissolver off-gas streams from nuclear reprocessing plants. Results show that, at subambient temperature (-40 0 to -80 0 C), the commercially available hydrogen mordenite has sufficient adsorptive capacity to be the most cost-effective material studied. Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite. The results indicate that a solid adsorbent system is feasible and competitive with other developing systems whih utilize fluorocarbon absorption and cryogenic distillation

Beam-foil level lifetimes in krypton III

International Nuclear Information System (INIS)

Coetzer, F.J.; Kotze, P.B.; Westhuizen, P. van der

1982-01-01

The radiative lifetimes of levels in doubly-ionized Krypton have been measured after foil excitation of a beam of Krypton particles in the wavelength range 120-500 nm. The results are compared with the experimental values obtained by Fink et al., as well as theoretical values resulting from Coulomb (C.A.) and single configuration Hartree-Fock (H.F.) calculations. (orig.)

Krypton-85 health risk assessment for a nuclear fuel reprocessing plant

International Nuclear Information System (INIS)

Mellinger, P.J.; Tanner, J.E.; Brackenbush, L.W.; Gilbert, E.S.

1984-08-01

A health risk assessment was conducted to investigate the impact of implementing regulations from the Environmental Protection Agency's Final Environmental Statement - 40 CFR 190 - Environmental Protection Requirements for Normal Operation of Activities in the Uranium Fuel Cycle. Potential risks involved in the routine release of 85 Kr from nuclear fuel reprocessing operations to the environment were compared to those resulting from the capture and storage of 85 Kr. The average occupationally exposed worker was estimated to receive about 400 to 600 mrem/y from 85 Kr recovery and immobilization activities. This dose is a factor of 20,000 to 30,000 higher than the estimated dose to the maximum offsite individual (0.02 mrem/y), and a factor of 130,000 to 200,000 higher than the dose received by the average member of the 50-mile population (0.003 mrem/y) from routine release of all 85 Kr. Given the uncertainties in the models used to generate lifetime risk numbers (0.02-0.027 radiation induced fatal cancers expected in the occupational workforce and 0.017 fatal cancers in the general population), the differences in total risks cannot be considered meaningful. There is certainly no reason to conclude that risks from 85 Kr routinely released to the environment are greater than those that would result from recovery, immobilization and storage of the noble gas. 22 references, 1 figure, 3 tables

TRANSFERT THERMIQUE INSTATIONNAIRE DANS UN MUR TRICOUCHES SUBISSANT UN CHANGEMENT DE PHASE PAR SOLIDIFICATION.

OpenAIRE

O Arfi; E Mezaache

2016-01-01

Une étude numérique du transfert de chaleur instationnaire dans un mur tricouches est présentée. Le modèle physique est basé sur l’équation de conduction thermique unidirectionnelle en tenant compte des équations de couplages au niveau des interfaces et des conditions convectives de surfaces. Les équations de transfert sont données en représentation enthalpique pour le matériau à changement de phase (MCP), et en formulation générale pour les régions solides. La formulation adimensionnelle a p...

Hyperpolarized krypton-83 as a contrast agent for magnetic resonance imaging.

Science.gov (United States)

Pavlovskaya, Galina E; Cleveland, Zackary I; Stupic, Karl F; Basaraba, Randall J; Meersmann, Thomas

2005-12-20

For the first time, magnetic resonance imaging (MRI) with hyperpolarized (hp) krypton-83 (83Kr) has become available. The relaxation of the nuclear spin of 83Kr atoms (I = 9/2) is driven by quadrupolar interactions during brief adsorption periods on surrounding material interfaces. Experiments in model systems reveal that the longitudinal relaxation of hp 83Kr gas strongly depends on the chemical composition of the materials. The relaxation-weighted contrast in hp 83Kr MRI allows for the distinction between hydrophobic and hydrophilic surfaces. The feasibility of hp 83Kr MRI of airways is tested in canine lung tissue by using krypton gas with natural abundance isotopic distribution. Additionally, the influence of magnetic field strength and the presence of a breathable concentration of molecular oxygen on longitudinal relaxation are investigated.

Enrichment Conditions of Krypton Onto Activated Carbons%活性炭对氪的富集条件

Institute of Scientific and Technical Information of China (English)

陈莉云; 曾宝珠; 张昌云; 武山; 刘龙波; 杨静; 韦冠一

2012-01-01

In order to monitor radioactive krypton distribution in the environment, active charcoal is used to enrich krypton before the sample can be submitted to further laboratory analysis. The importance and method of krypton enrichment were presented. The absorption behavior of krypton by charcoal was analyzed. The experimental setup was designed to investigate effects of working temperature, linear velocities, partial-pressure of krypton on the enrichment of krypton by charcoal. The micro-structure parameters of the absorbing material to characterize its absorbing property was used, and the experimental data with theoretical analysis to conclude that for CF-1450 was fitted. The saturation absorption capacity at 191 K is 32. 9 mL/g.%从环境监测角度,叙述了开展活性炭对氪富集条件研究的重要意义.以氪在活性炭上的动态吸附实验为基础,研究了活性炭、温度、气体线流速和氪的分压对氪富集的影响,利用吸附材料的微结构,通过吸附理论模型拟合实验数据,得到CF-1450活性炭在191 K下对氪的饱和吸附量为32.9 mL/g.

[Effect of krypton-containing gas mixture on Japanese quail embryo development].

Science.gov (United States)

Kussmaul', A R; Gur'eva, T S; Dadasheva, O A; Pavlov, N B; Pavlov, B N

2008-01-01

Investigated were effects of gas mixture with up to 3.0 kgs/cm2 of krypton on the embryonic development of domesticated Japanese quail (Coturnix coturnix japonica dom.). Results demonstrated absence of a serious krypton effect on Japanese quail embryos. Development of embryos proceeded in due course; morphometrically the experimental embryos were essentially similar to controls. It should be noted that despite exposure to acute hypoxic hypoxia during the initial 12 hours of development in the krypton-containing gas mixture, viability of quail embryos was high enough which can be ascribed to the krypton protective action. Besides, an additional experiment showed that krypton partial pressure of 5-5.5 kgs/cm2 produces the narcotic effect on adult Japanese quails.

A review of the separation and immobilisation of krypton arising from nuclear fuel reprocessing plant

International Nuclear Information System (INIS)

Judd, S.J.

1992-01-01

The techniques for the separation and immobilisation of 85 Kr are reviewed. Particular attention is paid to processes currently available or undergoing development on the technical to industrial scale. Of the separation processes, cryogenic distillation has reached the most advanced stage of development, with a pilot facility already undergoing radioactive demonstration. The PNC Kr-recovery pilot plant, which has a off-gas flow capacity of 110 m 3 hr -1 (approximately 1/4 the scale of THORP), is currently undergoing tests at Tokai Mura. Low-temperature absorption and adsorption processes have also reached the pilot plant stage but have yet to undergo radiological tests. The separated krypton has been conventionally stored as the compressed gas in cylinders, but progress made in encapsulation techniques suggest that more secure immobilisation can be achieved by encapsulation within a metal or zeolite matrix. Processes based on the implantation of krypton in a metal or metal alloy have been demonstrated on the technical scale with the radioactive gas. It is concluded that the technology for the separation, isolation and immobilisation of radioactive krypton is available only on a reduced scale compared with THORP. The investment cost of a 85 Kr management facility for THORP, based on cryogenic distillation followed by immobilisation by implantation in metal and assuming a 20 year plant life, is estimated at 51-57M pounds. The cost of prepurification of the off-gas stream is included in this figure. Accompanying operating costs, including those incurred by disposal of the encapsulate in geological formations, are estimated at 2.2-3.3 M pounds per annum. Further development work under radioactive conditions is still required prior to the application of existing technology to full-scale fuel reprocessing plant. (author)

A new site for 85Kr measurements on groundwater samples

International Nuclear Information System (INIS)

Lange, T.; Hebert, D.

2001-01-01

As a part of a new 85 Kr laboratory, which is currently being established at the Institute of Applied Physics in Freiberg, Germany, a modified CO 2 extractor for krypton sampling is used. The operation principle is simple and contamination-safe with a reasonable effort. Continuously pumped under pressure, the water passes a Venturi-type nozzle and degasses due to relaxing. The extracted gas mixture then enters a recirculation system flowing through a CO 2 trap (NaOH), molecular sieves and a cooled charcoal trap, where krypton and other components are adsorbed. Remaining gases reenter the system at the Venturi-type nozzle. To keep the circulation alive an additional helium support is needed. In a simple field experiment, extraction efficiencies up to 0.8 for 222 Rn have been measured.

A new site for 85Kr measurements on groundwater samples

Science.gov (United States)

Lange, T.; Hebert, D.

2001-06-01

As a part of a new 85Kr laboratory, which is currently being established at the Institute of Applied Physics in Freiberg, Germany, a modified CO 2 extractor for krypton sampling is used. The operation principle is simple and contamination-safe with a reasonable effort. Continuously pumped under pressure, the water passes a Venturi-type nozzle and degasses due to relaxing. The extracted gas mixture then enters a recirculation system flowing through a CO 2 trap (NaOH), molecular sieves and a cooled charcoal trap, where krypton and other components are adsorbed. Remaining gases reenter the system at the Venturi-type nozzle. To keep the circulation alive an additional helium support is needed. In a simple field experiment, extraction efficiencies up to 0.8 for 222Rn have been measured.

TRANSFERT THERMIQUE INSTATIONNAIRE DANS UN MUR TRICOUCHES SUBISSANT UN CHANGEMENT DE PHASE PAR SOLIDIFICATION.

Directory of Open Access Journals (Sweden)

O Arfi

2016-05-01

Full Text Available Une étude numérique du transfert de chaleur instationnaire dans un mur tricouches est présentée. Le modèle physique est basé sur l’équation de conduction thermique unidirectionnelle en tenant compte des équations de couplages au niveau des interfaces et des conditions convectives de surfaces. Les équations de transfert sont données en représentation enthalpique pour le matériau à changement de phase (MCP, et en formulation générale pour les régions solides. La formulation adimensionnelle a permis de dégager les principaux paramètres affectant le transfert : nombre de Biot (Bi, nombre de Stephan (Ste et le degré de surchauffe (qm. La discrétisation des équations est réalisée en utilisant la méthode des volumes finis selon un schéma explicite. La solution numérique est obtenue par une méthode itérative basée sur la notion d’enthalpie critique. L’étude de l’influence de la condition convective chaude, gouvernée par  Bi¥,cet θ¥,c , a montré que la présence des couches solides affecte la cinétique de la solidification, les limites de la solidification et le transfert de chaleur par un effet de stockage et de déstockage d’énergie sensible. L’influence de la température θ¥,c sur le processus de changement de phase est fortement dépendante du nombre de Biot Bi¥,c.

Technical and economic evaluation of processes for krypton-85 recovery from power fuel-reprocessing plant off-gas

International Nuclear Information System (INIS)

Waggoner, R.C.

1982-08-01

A technical and economical analysis has been made of methods for collecting and concentrating krypton from the off-gas from a typical nuclear fuel reprocessing plant. The methods considered were cryogenic distillation, fluorocarbon absorption, mordenite adsorption, and selective permeation. The conclusions reached were: Cryogenic distillation is the only demonstrated route to date. Fluorocarbon absorption may offer economic and technical advantages if fully developed and demonstrated. Mordenite adsorption has been demonstrated only on a bench scale and is estimated to cost more than either cryogenic distillation or fluorocarbon absorption. Selective permeation through a silicone rubber membrane is not sufficiently selective for the route to be cost effective

Separation of the fission product noble gases krypton and xenon from dissolver off-gas in reprocessing HTGR-fuel

International Nuclear Information System (INIS)

Bohnenstingl, J.; Djoa, S.H.; Laser, M.; Mastera, S.; Merz, E.; Morschl, P.

1976-01-01

This paper describes a process developed for the retainment and separation of volatile ( 3 H, 129+131 I) and gaseous ( 85 Kr, Xe) fission products from the off-gas produced during dissolution of HTGR-fuel. To prevent unnecessary dilution of liberated noble gases by surrounding atmosphere, a helium purge-gas cycle is applied to enable a coarse fractionating of krypton and xenon by cold-trapping at about 80 0 K after precleaning the gas stream. The process consists of the following steps: deposition of droplets and solid aerosols; chemisorption of iodine on silver impregnated silica gel; catalytic removal of nitrogen oxides and oxygen; drying of the process gas stream; final filtering of abraded solids; deposition of xenon in solid form at 80 0 K and low subpressure; deposition of krypton in solid form at 80 0 K after compression to about 6 bar; decontamination of 85 Kr-containing xenon by batch distillation for eventual industrial utilization; and removal of nitrogen and argon enrichment during continuous operation in the purge-gas stream by inleaking air with charcoal. A continuously operating dissolver vessel, closed to the surrounding atmosphere, yields a very high content of noble gases, i.e., 0.35 vol % krypton and 2.0 vol % xenon. The presented off-gas treatment unit is operated in cold runs with 1 / 3 of the full capacity and can treat about 1 m 3 STP/h helium, corresponding to a quantity of about 10,000 MW/sub e/ HTGR-fuel reprocessing plant

Study of structural and transport properties of argon, krypton, and their binary mixtures at different temperatures.

Science.gov (United States)

Ghimire, Sunil; Adhikari, Narayan Prasad

2017-03-01

Molecular dynamics simulation of argon, krypton, and their binary mixtures were performed at different temperatures and constant pressure (P = 1.013 bar) using GROMACS - Groningen Machine for Chemical Simulations. The gases are modeled by Lennard-Jones pair potential, with parameters taken from the literature. The study of radial distribution functions (RDFs) shows a single peak which indicates that there is no packing effect in gaseous state for argon, krypton, and their binary mixtures. The self-diffusion coefficients of argon and krypton is determined by using mean-square displacement(MSD) method and the mutual diffusion coefficients of binary mixtures are determined using Darken's relation. The values of simulated diffusion coefficients are compared with their corresponding theoretical values, numerical estimation, and experimental data. A good agreement between these sets of data is found. The diffusion coefficients obey Arrhenius behavior to a good extent for both pure components and binary mixtures. The values of simulated diffusion coefficient are used to estimate viscosities and thermal conductivities which agree with theoretical values, numerical estimation, and experimental data within 10 %. These results support that the LJ potential is sufficient for description of molecular interactions in argon and krypton.

In situ measurements of krypton in xenon gas with a quadrupole mass spectrometer following a cold-trap at a temporarily reduced pumping speed

Energy Technology Data Exchange (ETDEWEB)

Brown, Ethan; Rosendahl, Stephan; Huhmann, Christian; Kettling, Hans; Schlak, Martin; Weinheimer, Christian [Muenster Univ. (Germany). Inst. fuer Kernphysik

2013-07-01

Liquid xenon detectors have risen to be extremely competitive for dark matter and neutrinoless double-beta decay searches. In order to achieve the required sensitivity, backgrounds must be reduced substantially. One important background is the beta-decay of {sup 85}Kr, which constitutes a uniform internal background in liquid xenon detectors. Cryogenic distillation can be used to reduce the krypton concentration to acceptable levels, but gas diagnostics become incredibly difficult at these ultra-pure levels. A new method for measuring the concentration of krypton in xenon has been developed, expanding on the existing technique of a cold trap and a Residual Gas Analyzer (RGA). By using a liquid nitrogen cold trap, one can take advantage of the difference in vapor pressures of krypton in xenon to freeze most of the xenon gas while allowing the krypton to pass to the measurement chamber. Here, only a few milliliters of xenon is expended in the measurement, while achieving a sensitivity of sub ppb (parts per billion). The key change is the use of a butterfly valve to partially close the opening in front of the turbomolecular pump, thereby reducing the effective pumping speed and enhancing the RGA signal.

Cylindrical ionization chamber with compressed krypton

International Nuclear Information System (INIS)

Kuz'minov, V.V.; Novikov, V.M.; Pomanskii, A.A.; Pritychenko, B.V.; Viyar, J.; Garcia, E.; Morales, A.; Morales, J.; Nunes-Lagos, R.; Puimedon, J.; Saens, K.; Salinas, A.; Sarsa, M.

1993-01-01

A cylindrical ionization chamber with a grid is used to search for double positron decay and atomic electron conversion to a positron in 78 Kr. Krypton is the working gas material of the chamber. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. The energy resolution is 2.1% for an energy of 1.84 MeV (the source of γ-quanta is 88 Y) when the chamber is filled with a mixture of Kr+0.2% H 2 under a pressure of 25 atm

Accurate virial coefficients of gaseous krypton from state-of-the-art ab initio potential and polarizability of the krypton dimer

Science.gov (United States)

Song, Bo; Waldrop, Jonathan M.; Wang, Xiaopo; Patkowski, Konrad

2018-01-01

We have developed a new krypton-krypton interaction-induced isotropic dipole polarizability curve based on high-level ab initio methods. The determination was carried out using the coupled-cluster singles and doubles plus perturbative triples method with very large basis sets up to augmented correlation-consistent sextuple zeta as well as the corrections for core-core and core-valence correlation and relativistic effects. The analytical function of polarizability and our recently constructed reference interatomic potential [J. M. Waldrop et al., J. Chem. Phys. 142, 204307 (2015)] were used to predict the thermophysical and electromagnetic properties of krypton gas. The second pressure, acoustic, and dielectric virial coefficients were computed for the temperature range of 116 K-5000 K using classical statistical mechanics supplemented with high-order quantum corrections. The virial coefficients calculated were compared with the generally less precise available experimental data as well as with values computed from other potentials in the literature {in particular, the recent highly accurate potential of Jäger et al. [J. Chem. Phys. 144, 114304 (2016)]}. The detailed examination in this work suggests that the present theoretical prediction can be applied as reference values in disciplines involving thermophysical and electromagnetic properties of krypton gas.

Kinetics of inhaled krypton in the blood of pregnant ewes and their fetuses

International Nuclear Information System (INIS)

Meznarich, H.K.; Sikov, M.R.; Ballou, J.E.

1989-01-01

There has been concern about exposure of pregnant women and their fetuses to radiokrypton (Kr-85) released to the general environment. This led to previous studies on the distribution and effects of inhaled Kr-85 in sheep and rats. The data on hematogenous concentrations obtained during and after continuous inhalation by pregnant ewes had neither been analyzed nor reported in detail, which led to the kinetic analyses reported in this communication. Indwelling catheters were placed in an artery and a vein of pregnant ewes, and into a fetal artery or vein at gestational ages between 93 and 123 days. Ewes were exposed for 1.5 to 2 hors via a face mask to an atmosphere of 50 nCi/ml (1850 Bq/ml) Kr-85 in air; mean respiration rates were about 20 breaths per min. Blood samples were collected from each catheter at intervals throughout the accumulation and steady-state periods, and during a 90-min period following discontinuation of exposure. Results from 7 ewes, in which complete sampling was obtained, showed that both maternal fetal blood concentrations of Kr rose rapidly and attained a steady state by approximately 1 hr after initiation of exposure. The steady state concentrations of Kr-85 were significantly higher in maternal venous blood than in maternal arterial or fetal blood. There were no significant concentration differences between fetal arterial and venous bloods. The rate of disappearance of Kr-85 (per min) from maternal and fetal blood after discontinuation of exposure, 0.17 ± 0.02 and 0.06 ± 0.01, respectively, were significantly different. Thus, krypton is freely accessible to the fetal blood and rapidly reaches and maintains an equilibrium state with maternal blood during continuous exposure, although it disappears from fetal blood less rapidly after cessation of exposure

A new site for 85Kr measurements on groundwater samples

International Nuclear Information System (INIS)

Lange, T.; Hebert, D.

2000-01-01

Analysis of stable and radioactive isotopes is essential as a complement to geochemistry and geohydraulic investigations on groundwater regimes and their genesis. This is widely acknowledged also for the determination of the specific activity of 85 Kr in groundwater. The geochemical inertness and well-defined input function of 85 Kr allow estimates of groundwater age and enhance characterization of groundwater flow and components in many aquifer systems. A new site for measurement of the 85 Kr specific activity has been established at the Institute of Applied Physics at the Freiberg University, Saxony. Under normal conditions ca. 80 μl krypton are dissolved in 1 m 3 of water in contact with air. Therefore gas extraction has to be most effectively. A modified CO 2 extractor of 45 cm x 10 cm was chosen. The water is continuously pumped under pressure (3 - 4 bar) passing a Venturi-type nozzle, which simultaneously operates as a water-jet pump. The extracted gas flows through a CO 2 trap (NaOH 10 %), a H 2 O cold trap, through molecular sieves (5, 3 A) and a charcoal column, cooled by liquid nitrogen, where krypton, nitrogene and other components are adsorbed. Remaining gases re-enter the extractor at the Venturi-type nozzle. A small membrane pump supports the circulation. Due to the special design of the water outlet, contamination of the sample is avoided. Optional a compact stove heats the water to improve the extraction efficiency. If pressure supply is high enough, additional extractors can be run simultaneously. In a test run the recovery for radon was around 65 to 70 %. Further preparation steps of the raw krypton sample is performed in the laboratory. To obtain a good first enrichment a tube furnace filled with chrome powder is used to separate nitrogen and oxygen from the sample at 900 deg C. The following enrichment steps are performed by a preparation setup developed at GSF-Institute for Hydrology, Neuherberg. (author)

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1982-01-01

An experimental laboratory program was conducted to develop economical solid adsorbents for the retention of krypton from a dissolver off-gas stream. The study indicates that a solid adsorbent system is feasible and competitive with other developing systems which utilize fluorocarbon absorption nd cryogenic distillation. This technology may have potential applications not only in nuclear fuel reprocessing plants, but also in nuclear reactors and in environmental monitoring. Of the 13 prospective adsorbents evaluated with respect to adsorption capacity and cost, the commercially available hydrogen mordenite was the most cost-effective material at subambient temperatures (-40 0 to -80 0 C). Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite

Determination of the separation efficiencies of a single-stage cryogenic distillation setup to remove krypton out of xenon by using a (83m)Kr tracer method.

Science.gov (United States)

Rosendahl, S; Brown, E; Cristescu, I; Fieguth, A; Huhmann, C; Lebeda, O; Murra, M; Weinheimer, C

2015-11-01

The separation of krypton and xenon is of particular importance for the field of direct dark matter search with liquid xenon detectors. The intrinsic contamination of the xenon with radioactive (85)Kr makes a significant background for these kinds of low count-rate experiments and has to be removed beforehand. This can be achieved by cryogenic distillation, a technique widely used in industry, using the different vapor pressures of krypton and xenon. In this paper, we present an investigation on the separation performance of a single stage distillation system using a radioactive (83m)Kr-tracer method. The separation characteristics under different operation conditions are determined for very low concentrations of krypton in xenon at the level of (83m)Kr/Xe = 1.9 ⋅ 10(-15), demonstrating, that cryogenic distillation in this regime is working. The observed separation is in agreement with the expectation from the different volatilities of krypton and xenon. This cryogenic distillation station is the first step on the way to a multi-stage cryogenic distillation column for the next generation of direct dark matter experiment XENON1T.

Krypton for computed tomography lung ventilation imaging: preliminary animal data.

Science.gov (United States)

Mahnken, Andreas H; Jost, Gregor; Pietsch, Hubertus

2015-05-01

The objective of this study was to assess the feasibility and safety of krypton ventilation imaging with intraindividual comparison to xenon ventilation computed tomography (CT). In a first step, attenuation of different concentrations of xenon and krypton was analyzed in a phantom setting. Thereafter, 7 male New Zealand white rabbits (4.4-6.0 kg) were included in an animal study. After orotracheal intubation, an unenhanced CT scan was obtained in end-inspiratory breath-hold. Thereafter, xenon- (30%) and krypton-enhanced (70%) ventilation CT was performed in random order. After a 2-minute wash-in of gas A, CT imaging was performed. After a 45-minute wash-out period and another 2-minute wash-in of gas B, another CT scan was performed using the same scan protocol. Heart rate and oxygen saturation were measured. Unenhanced and krypton or xenon data were registered and subtracted using a nonrigid image registration tool. Enhancement was quantified and statistically analyzed. One animal had to be excluded from data analysis owing to problems during intubation. The CT scans in the remaining 6 animals were completed without complications. There were no relevant differences in oxygen saturation or heart rate between the scans. Xenon resulted in a mean increase of enhancement of 35.3 ± 5.5 HU, whereas krypton achieved a mean increase of 21.9 ± 1.8 HU in enhancement (P = 0.0055). The use of krypton for lung ventilation imaging appears to be feasible and safe. Despite the use of a markedly higher concentration of krypton, enhancement is significantly worse when compared with xenon CT ventilation imaging, but sufficiently high for CT ventilation imaging studies.

Evaluation of activated charcoal for dynamic adsorption of krypton and xenon

International Nuclear Information System (INIS)

Khan, A.A.; Deshingkar, D.S.; Ramarathinam, K.; Kishore, A.G.

1975-01-01

From the standpoint of radiation safety, the release of radioactive krypton and xenon from power reactors should be kept as low as practicable. The decay of shortlived isotopes of krypton and xenon by adsorptive delay on activated charcoal has shown promising results for this purpose. The delay provided by activated charcoal is proportional to the dynamic adsorption coefficients of these gases which are characteristic of the adsorbent. These coefficients were determined for krypton and xenon on indigenous gas-adsorbing activated charcoal at different moisture contents of carrier air stream and activated charcoal, concentrations of krypton around ambient temperatures, to find its suitability for designing adsorber columns. (author)

Selective adsorption-desorption method for the enrichment of krypton

International Nuclear Information System (INIS)

Yuasa, Y.; Ohta, M.; Watanabe, A.; Tani, A.; Takashima, N.

1975-01-01

Selective adsorption-desorption method has been developed as an effective means of enriching krypton and xenon gases. A seriesof laboratory-scale tests were performed to provide some basic data of the method when applied to off-gas streams of nuclear power plants. For the first step of the enrichment process of the experiments, krypton was adsorbed on solid adsorbents from dilute mixtures with air at temperatures ranging from -50 0 C to -170 0 C. After the complete breakthrough was obtained, the adsorption bed was evacuated at low temperature by a vacuum pump. By combining these two steps krypton was highly enriched on the adsorbents, and the enrichment factor for krypton was calculated as the product of individual enrichment factors of each step. Two types of adsorbents, coconut charcoal and molecular sieves 5A, were used. Experimental results showed that the present method gave the greater enrichment factor than the conventional method which used selective adsorption step only. (U.S.)

APPARENT 85KRYPTON AGES OF GROUNDWATER WITHIN THE ROYAL WATERSHED, MAINE, USA

Science.gov (United States)

85Kr activities were determined in 264 domestic and municipal wells from 2002-2004 in the Royal watershed (361 km2), Maine. Gas extraction for 85Kr from wells was effected directly via a well-head methodology permitting efficient widespread analys...

Thermal stability of the krypton Hall effect thruster

Directory of Open Access Journals (Sweden)

Szelecka Agnieszka

2017-03-01

Full Text Available The Krypton Large IMpulse Thruster (KLIMT ESA/PECS project, which has been implemented in the Institute of Plasma Physics and Laser Microfusion (IPPLM and now is approaching its final phase, was aimed at incremental development of a ~500 W class Hall effect thruster (HET. Xenon, predominantly used as a propellant in the state-of-the-art HETs, is extremely expensive. Krypton has been considered as a cheaper alternative since more than fifteen years; however, to the best knowledge of the authors, there has not been a HET model especially designed for this noble gas. To address this issue, KLIMT has been geared towards operation primarily with krypton. During the project, three subsequent prototype versions of the thruster were designed, manufactured and tested, aimed at gradual improvement of each next exemplar. In the current paper, the heat loads in new engine have been discussed. It has been shown that thermal equilibrium of the thruster is gained within the safety limits of the materials used. Extensive testing with both gases was performed to compare KLIMT’s thermal behaviour when supplied with krypton and xenon propellants.

Contribution to the study of the structure of silver krypton solid solutions; Contribution a l'etude de la structure des solutions solides argent-krypton

Energy Technology Data Exchange (ETDEWEB)

Levy, V; Tullairet, J; Delaplace, J; Antolin-Baudier, J; Adda, Y [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The silver-krypton solid solutions formed by electrical discharge have been studied by X-rays, electrical resistivity and electronic transmission microscopy. The crystalline parameter and residual resistivity measurements have shown that the krypton atom behaves very differently to those of other elements of the periodic classification when dissolved in silver. The recovery of the crystalline parameter and of the electrical resistivity has been studied as a function of temperature. (authors) [French] Les solutions solides argent, krypton, realisees par decharges electrique ont ete etudiees par Rayons X, resistivite electrique et microscopie electronique en transmission. Les mesures de parametre cristallin et de resistivite residuelle ont montre que le comportement de l'atome de krypton est tres different de celui des autres elements de la classification periodique en solution dans l'argent. La restauration du parametre cristallin et de la resistivite electrique en fonction de la temperature a ete etudiee. (auteurs)

Empirical evaluation of the radiative cooling coefficient for krypton gas in the FTU plasma

International Nuclear Information System (INIS)

Fournier, K.B.; Pacella, D.; Mazzitelli, G.; Stutman, D.; Soukanovskii, V.; Goldstein, W.H.

1997-01-01

For future fusion reactors, a careful balance must be achieved between the cooling of the outer plasma via impurity radiation and the deleterious effects of inevitable core penetration by impurity ions. We have injected krypton gas into the Frascati Tokamak Upgrade (FTU) plasma. The measured visible bremsstrahlung and bolometric signals from krypton have been inverted and the resulting radial impurity density profile and power loss profile for krypton gas are extracted. Using the measured electron density and temperature profiles, the radiative cooling coefficient for krypton is derived. The level of intrinsic impurities (Mo, Cr, Mn and Fe) in the plasma during the krypton puffing is monitored with a VUV SPRED spectrometer. Models for krypton emissivity from the literature are compared to our measured results. 7 figs

Internal plasma potential measurements of a Hall thruster using xenon and krypton propellant

International Nuclear Information System (INIS)

Linnell, Jesse A.; Gallimore, Alec D.

2006-01-01

For krypton to become a realistic option for Hall thruster operation, it is necessary to understand the performance gap between xenon and krypton and what can be done to reduce it. A floating emissive probe is used with the Plasmadynamics and Electric Propulsion Laboratory's High-speed Axial Reciprocating Probe system to map the internal plasma potential structure of the NASA-173Mv1 Hall thruster [R. R. Hofer, R. S. Jankovsky, and A. D. Gallimore, J. Propulsion Power 22, 721 (2006); and ibid.22, 732 (2006)] using xenon and krypton propellant. Measurements are taken for both propellants at discharge voltages of 500 and 600 V. Electron temperatures and electric fields are also reported. The acceleration zone and equipotential lines are found to be strongly linked to the magnetic-field lines. The electrostatic plasma lens of the NASA-173Mv1 Hall thruster strongly focuses the xenon ions toward the center of the discharge channel, whereas the krypton ions are defocused. Krypton is also found to have a longer acceleration zone than the xenon cases. These results explain the large beam divergence observed with krypton operation. Krypton and xenon have similar maximum electron temperatures and similar lengths of the high electron temperature zone, although the high electron temperature zone is located farther downstream in the krypton case

Development of the krypton absorption in liquid carbon dioxide (KALC) process for HTGR off-gas reprocessing

International Nuclear Information System (INIS)

Glass, R.W.; Beaujean, H.W.R.; Cochran, H.D. Jr.; Haas, P.A.; Levins, D.M.; Woods, W.M.

1975-01-01

Reprocessing of High-Temperature Gas-Cooled Reactor (HTGR) fuel involves burning of the graphite-matrix elements to release the fuel for recovery purposes. The resulting off-gas is primarily CO 2 with residual amounts of N 2 , O 2 , and CO, together with fission products. Trace quantities of krypton-85 must be recovered in a concentrated form from the gas stream, but processes commonly employed for rare gas removal and concentration are not suitable for use with off-gas from graphite burning. The KALC (Krypton Absorption in Liquid CO 2 ) process employs liquid CO 2 as a volatile solvent for the krypton and is, therefore, uniquely suited to the task. Engineering development of the KALC process is currently under way at the Oak Ridge National Laboratory (ORNL) and the Oak Ridge Gaseous Diffusion Plant (ORGDP). The ORNL system is designed for close study of the individual separation operations involved in the KALC process, while the ORGDP system provides a complete pilot facility for demonstrating combined operations on a somewhat larger scale. Packed column performance and process control procedures have been of prime importance in the initial studies. Computer programs have been prepared to analyze and model operational performance of the KALC studies, and special sampling and in-line monitoring systems have been developed for use in the experimental facilities. (U.S.)

Study on immobilization technology of krypton gas by ion-implantation and sputtering process

International Nuclear Information System (INIS)

Hayashi, S.; Kamiya, S.; Ikeda, S.; Nakanishi, Y.

1997-01-01

At the Waste Technology Development Division of PNC''s Tokai Works, we have been carrying out the development of the recovering and storing technology of radioactive krypton to reduce the radioactive gaseous effluent released to the environment arising from reprocessing of nuclear spent fuels. As a part of this technical development, the method of storing radioactive krypton is an encapsulation in a metal matrix which appears to offer the most secure immobilization of krypton. From the result of the ion-implantation test used non-radioactive krypton and the evaluation of electrical characteristics, we have selected the metallic materials, they are Nickel and Yttrium, and designed the vessel and the apparatus which continuously immobilized the krypton into metal matrix. This article described the following experiment result. (1) The long-term immobilization technology was established with respect to handling a equipment and plasma controlling. (2) Stability of the krypton immobilized alloy was considered satisfactory because the release was tolerably small. (author)

L-shell spectroscopic diagnostics of radiation from krypton HED plasma sources

Energy Technology Data Exchange (ETDEWEB)

Petkov, E. E., E-mail: emilp@unr.edu; Safronova, A. S.; Kantsyrev, V. L.; Shlyaptseva, V. V. [University of Nevada, Reno, Nevada 89557 (United States); Rawat, R. S.; Tan, K. S. [National Institute of Education, Nanyang Technological University, Singapore 637616 (Singapore); Beiersdorfer, P.; Brown, G. V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hell, N. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, 96049 Bamberg (Germany)

2016-11-15

X-ray spectroscopy is a useful tool for diagnosing plasma sources due to its non-invasive nature. One such source is the dense plasma focus (DPF). Recent interest has developed to demonstrate its potential application as a soft x-ray source. We present the first spectroscopic studies of krypton high energy density plasmas produced on a 3 kJ DPF device in Singapore. In order to diagnose spectral features, and to obtain a more comprehensive understanding of plasma parameters, a new non-local thermodynamic equilibrium L-shell kinetic model for krypton was developed. It has the capability of incorporating hot electrons, with different electron distribution functions, in order to examine the effects that they have on emission spectra. To further substantiate the validity of this model, it is also benchmarked with data gathered from experiments on the electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory, where data were collected using the high resolution EBIT calorimeter spectrometer.

L-shell spectroscopic diagnostics of radiation from krypton HED plasma sources.

Science.gov (United States)

Petkov, E E; Safronova, A S; Kantsyrev, V L; Shlyaptseva, V V; Rawat, R S; Tan, K S; Beiersdorfer, P; Hell, N; Brown, G V

2016-11-01

X-ray spectroscopy is a useful tool for diagnosing plasma sources due to its non-invasive nature. One such source is the dense plasma focus (DPF). Recent interest has developed to demonstrate its potential application as a soft x-ray source. We present the first spectroscopic studies of krypton high energy density plasmas produced on a 3 kJ DPF device in Singapore. In order to diagnose spectral features, and to obtain a more comprehensive understanding of plasma parameters, a new non-local thermodynamic equilibrium L-shell kinetic model for krypton was developed. It has the capability of incorporating hot electrons, with different electron distribution functions, in order to examine the effects that they have on emission spectra. To further substantiate the validity of this model, it is also benchmarked with data gathered from experiments on the electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory, where data were collected using the high resolution EBIT calorimeter spectrometer.

Global characteristics of an ATON stationary plasma thruster operating with krypton and xenon

International Nuclear Information System (INIS)

Bugrova, A.I.; Lipatov, A.S.; Solomatina, L.V.; Morozov, A.I.

2002-01-01

Paper contains the experimental results of operation of the ATON plasma thruster operating with krypton and xenon. It is shown that consumption of a working gas for consumption of a working gas the krypton base thrust is higher in contrast to xenon base one at lower efficiency. In case of krypton use one obtained the efficiency constituting ∼ 60% at specific pulse reaching 3000 s. Jet divergence in case of krypton use is ∼ ± 22 deg in contrast to ∼ ± 11 deg in case of xenon use [ru

Separation of radioactive krypton from carbon dioxide and oxygen with molecular sieves

International Nuclear Information System (INIS)

Forsberg, C.W.

1977-10-01

In the reprocessing of HTGR nuclear fuels, the off-gas cleanup system generates a stream containing about 1 percent krypton, 90+ percent CO 2 , and various amounts of O 2 , N 2 , and xenon. The krypton is radioactive and must be separated from the CO 2 before it is bottled or zeolite-encapsulated for final disposal. A series of theoretical and experimental investigations to find the best method for separating CO 2 and krypton under the required conditions showed that 5A molecular sieves near O 0 C and 1.01 x 10 5 Pa (1 atm) provided the most effective separation. Molecular sieves are powerful solid adsorbents for CO 2 but weak adsorbents for krypton. For a typical expected CO 2 -O 2 -krytpon gas mixture, a molecular sieve bed adsorbs the CO 2 , allows the O 2 to pass freely through the bed, and concentrates the krypton before it exits the bed. The process selected and investigated is called frontal analysis gas chromatography

Krypton calibration of time projection chambers of the NA61/SHINE experiment

CERN Document Server

Naskret, Michal

The NA61/SHINE experiment at CERN is searching for the critical point in phase transition between quark-gluon plasma and hadronic matter. To do so we use the most precise apparatus - Time Projection Chamber. Its main task is to find trajectories of particles created in a relativistic collision. In order to improve efficiency of TPCs, we introduce calibration using radioactive krypton gas. Simulation of events in a TPC cham- ber through a decay of excited krypton atoms gives us a spectrum, which is later fitted to the model spectrum of krypton from a Monte-Carlo simulation. The data obtained in such a way serves us to determine malfunctioning electronics in TPCs. Thanks to the krypton calibration we can create a map of pad by pad gains. In this thesis I will de- scribe in detail the NA61 experimental setup, krypton calibration procedure, calibration algorithm and results for recent calibration runs

Carbon dioxide-krypton separation and radon removal from nuclear-fuel-reprocessing off-gas streams

International Nuclear Information System (INIS)

Hirsch, P.M.; Higuchi, K.Y.; Abraham, L.

1982-07-01

General Atomic Company (GA) is conducting pilot-plant-scale tests that simulate the treatment of radioactive and other noxious volatile and gaseous constituents of off-gas streams from nuclear reprocessing plants. This paper reports the results of engineering-scale tests performed on the CO 2 /krypton separation and radon holdup/decay subsystems of the GA integrated off-gas treatment system. Separation of CO 2 from krypton-containing gas streams is necessary to facilitate subsequent waste processing and krypton storage. Molecular sieve 5A achieved this separation in dissolver off-gas streams containing relatively low krypton and CO 2 concentrations and in krypton-rich product streams from processes such as the krypton absorption in liquid carbon dioxide (KALC) process. The CO 2 /krypton separation unit is a 30.5-cm-diameter x 1.8-m-long column containing molecular sieve 5A. The loading capacity for CO 2 was determined for gas mixtures containing 250 ppM to 2.2% CO 2 and 170 to 750 ppM krypton in either N 2 or air. Gas streams rich in CO 2 were diluted with N 2 to reduce the temperature rise from the heat of adsorption, which would otherwise affect loading capacity. The effluent CO 2 concentration prior to breakthrough was less than 10 ppM, and the adsorption capacity for krypton was negligible. Krypton was monitored on-line with a time-of-flight mass spectrometer and its concentration determined quantitatively by a method of continuous analysis, i.e., selected-ion monitoring. Radon-220 was treated by holdup and decay on a column of synthetic H-mordenite. The Rn-220 concentration was monitored on-line with flow-through diffused-junction alpha detectors. Single-channel analyzers were utilized to isolate the 6.287-MeV alpha energy band characteristic of Rn-220 decay from energy bands due to daughter products

The Liquid Krypton Calorimeter Cryogenics for the NA48 Experiment

CERN Document Server

Bremer, J; Dauvergne, J P; Gonidec, A; Kesseler, G; Kubischta, Werner; Linser, G; Schinzel, D; Taureg, Hans; Wertelaers, Piet

1998-01-01

The NA48 cryogenic system has to provide stable thermal conditions (120 K) in a 9000 liter liquid krypton calorimeter, and has to ensure safe and loss free storage of the liquid during idle periods. Direct cooling of the krypton by nitrogen is used in emergency cases, while an intermediate cooler, containing saturated liquid argon at around 10 bar (117 K) is used under normal operation conditions when high thermal stability is needed. The krypton pressure is, during data taking, regulated to a value of (1.05 ± 0.01) bar for a period of about 8 months of continuous operation of the calorimeter.

85Kr and 39Ar background in GENIUS

International Nuclear Information System (INIS)

Klapdor Kleingrothaus, H.V.; Tomei, C.

2003-01-01

GENIUS is a proposal for a large-scale detector of rare events like double beta decay, cold dark matter and low-energy solar neutrinos in real time. The idea of GENIUS is to operate a large amount of 'naked' Ge detectors in liquid nitrogen, with the aim of reducing the background down to a level of 10 -3 counts/kg keV yr. In this work, we investigate the contribution to the background of GENIUS coming from argon ( 39 Ar) and krypton ( 85 Kr) contamination in the liquid nitrogen

Griffe cubitale d'origine lépreuse traitée par transfert tendineux de ...

African Journals Online (AJOL)

Griffe cubitale d'origine lépreuse traitée par transfert tendineux de Lasso Zancolli: à propos d'un cas. Adil El Alaoui, Mouhcine Sbiyaa, Aliou Bah, Ilyas Rabhi, Amine Mezzani, Amine Marzouki, Fawzi Boutayeb ...

Krypton based adsorption type cryogenic refrigerator

Science.gov (United States)

Jones, Jack A. (Inventor); Schember, Helene R. (Inventor)

1989-01-01

Krypton and a monolithic porous carbon such as Saran carbon are used respectively as the sorbate and sorbent of an adsorption type refrigerator to improve refrigeration efficiency and operational longevity.

Operation and technology development of the radioactive xenon and krypton detection equipment

International Nuclear Information System (INIS)

Lee, Wanno; Choi, Sangdo; Ji, Youngyong; Lim, Jong Myoung; Cho, Young Hyun; Kang, Han Beul; Lee, Hoon; Kang, Moon Ja; Choi, Kun Sik

2013-03-01

Operation and technology development of the radioactive xenon and krypton detection equipment - Advancement, independence of operation technology for BfS-IAR system(the simultaneous analysis of xenon and krypton) installed after North Korea nuclear tests in 2006 and establishment of background base-line for xenon and krypton radioactivity. - Enhanced detection and analysis capabilities for neighborhood nuclear activities through advanced research of noble gas detection technology. Results of the Project · The operation of xenon and krypton analysis system (BfS-IAR) · Operation of fixed adsorption system. · Operation of portable adsorption system · Exercise of emergency response and proficiency test with SAUNA. · Measurement of noble gas background at specific region in Korea. - Radioxenon levels at Dongdu Cheon is approximately 1.6 mBq/m 3 · Development of automation filling system for absorber cooling

THE RETENTION OF KRYPTON IN POLYCRYSTALLINE SILICON DURING HIGH-TEMPERATURE ANNEALING

NARCIS (Netherlands)

GREUTER, MJW; NIESEN, L; VANVEEN, A; EVANS, JH

1994-01-01

In a study into the annealing behaviour of silicon containing a few atomic per cent of krypton, it was found that, even at 0.87 of the silicon melting temperature, approximately 90% of the original krypton was still present. This result is compared with analogous work on metals where copious inert

Quenching of the resonance 5s({sup 3}P{sub 1}) state of krypton atoms in collisions with krypton and helium atoms

Energy Technology Data Exchange (ETDEWEB)

Zayarnyi, D A; L' dov, A Yu; Kholin, I V [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2014-11-30

The processes of collision quenching of the resonance 5s[3/2]{sub 1}{sup o}({sup 3}P{sub 1}) state of the krypton atom are studied by the absorption probe method in electron-beam-excited high-pressure He – Kr mixtures with a low content of krypton. The rate constants of plasmochemical reactions Kr* + Kr + He → Kr*{sub 2} + He [(4.21 ± 0.42) × 10{sup -33} cm{sup 6} s{sup -1}], Kr* + 2He → HeKr* + He [(4.5 ± 1.2) × 10{sup -36} cm{sup 6} s{sup -1}] and Kr* + He → products + He [(2.21 ± 0.22) × 10{sup -15} cm{sup 3} s{sup -1}] are measured for the first time. The rate constants of similar reactions are refined for krypton in the metastable 5s[3/2]{sub 2}{sup o} ({sup 3}P{sub 2}) state. (laser applications and other topics in quantum electronics)

Assessment of the potentially beneficial uses of krypton-85. Final report, Task 64

International Nuclear Information System (INIS)

Eggers, P.E.; Gawthrop, W.E.

1975-06-01

Results of a study aimed at assessing the potentially beneficial uses of 85 Kr indicate that self-luminous light sources appear to be the foremost benefical use of 85 Kr. Other assessed uses include heat sources for thermoelectric generators, heat sources for environmental control of submersibles, heat sources for thermodynamic energy cycles, polymerization processes, nondestructive testing, leak detection, biomedical applications, and liquid waste treatment. (TFD)

The saturation phenomenon in Kr85 ion implantation in metallic targets

International Nuclear Information System (INIS)

Baptista Junior, V. de P.

1978-01-01

Noble gases, as Krypton containing the radioative isotope Kr 85 , can be stably incorporated into a wide variety of solids and used as tracers or a kind of sensitive probe to measure chemical and physical phenomena. A general review is presented about the methods of incorporation with emphasis on ion bombardment and saturation. The problem of saturation of metal targets was correlated to certain properties in order to get a mathematical approach. Six properties were chosen as more significative to produce a simple model of saturation on experiments of ion implantation with Kr 85 at 45 KeV. The accuracy of the model is limited by the experimental error, the available data and its own simplicity. (Author) [pt

Krypton Adsorption on Zeolite-Templated Carbon and Anomalous Surface Thermodynamics.

Science.gov (United States)

Murialdo, Maxwell; Stadie, Nicholas P; Ahn, Channing C; Fultz, Brent

2015-07-28

Krypton adsorption was measured at eight temperatures between 253 and 433 K on a zeolite-templated carbon and two commercial carbons. The data were fitted using a generalized Langmuir isotherm model and thermodynamic properties were extracted. Differing from that on commercial carbons, krypton adsorption on the zeolite-templated carbon is accompanied by an increasing isosteric enthalpy of adsorption, rising by up to 1.4 kJ mol(-1) as a function of coverage. This increase is a result of enhanced adsorbate-adsorbate interactions promoted by the ordered, nanostructured surface of the adsorbent. An assessment of the strength and nature of these adsorbate-adsorbate interactions is made by comparing the measured isosteric enthalpies of adsorption (and other thermodynamic quantities) to fundamental metrics of intermolecular interactions of krypton and other common gases.

Technical Note: Calibration device for the krypton hygrometer KH20

Directory of Open Access Journals (Sweden)

T. Foken

2012-08-01

Full Text Available A calibration device for krypton hygrometers (KH20, Campbell Scientific, Inc. with variable path length is presented. This unit allows for in-situ calibrations of the krypton hygrometer, which is typically not very stable over time, during measuring campaigns. It was constructed mainly for application at high altitudes and low temperatures, where further improvements are needed to the IR-hygrometers which are normally used. The changing path length requires that a changing concentration of the absorber be simulated. Because oxygen absorbs more strongly than water vapour, the calibration is made against oxygen and transferred to water vapour. The design of the calibration instrument is made as one unit containing a stepper motor system, PC and humidity sensor. For the calibration, it is necessary to install the krypton hygrometer on this unit.

Krypton and xenon in the atmosphere of Venus

Science.gov (United States)

Donahue, T. M.; Hoffman, J. H.; Hodges, R. R., Jr.

1981-01-01

The paper reports a determination by the Pioneer Venus large probe neutral mass spectrometer of upper limits to the concentration of krypton and xenon along with most of their isotopes in the atmosphere of Venus. The upper limit to the krypton mixing ratio is estimated at 47 ppb, with a very conservative estimate at 69 ppb. The probable upper limit to the sum of the mixing ratios of the isotopes Xe-128, Xe-129, Xe-130, Xe-131, and Xe-132 is 40 ppb by volume, with a very conservative upper limit three times this large.

Krypton K-shell X-ray spectra recorded by the HENEX spectrometer

Energy Technology Data Exchange (ETDEWEB)

Seely, J.F. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)]. E-mail: john.seely@nrl.navy.mil; Back, C.A. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Constantin, C. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Lee, R.W. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Chung, H.-K. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Hudson, L.T. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Szabo, C.I. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Henins, A. [National Institute of Standards and Technology, Gaithersburg MD 20899 (United States); Holland, G.E. [SFA Inc., 9315 Largo Drive West Suite 200, Largo MD 20774 (United States); Atkin, R. [Tiger Innovations, L.L.C., 3610 Vacation Lane, Arlington VA 22207 (United States); Marlin, L. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)

2006-05-15

High-resolution X-ray spectra were recorded by the High-Energy Electronic X-ray (HENEX) spectrometer from a variety of targets irradiated by the Omega laser at the Laboratory for Laser Energetics. The HENEX spectrometer utilizes four reflection crystals covering the 1-20keV energy range and one quartz(10-11) transmission crystal (Laue geometry) covering the 11-40keV range. The time-integrated spectral images were recorded on five CMOS X-ray detectors. In the spectra recorded from krypton-filled gasbag and hohlraum targets, the helium-like K-shell transitions n=1-2, 1-3, and 1-4 appeared in the 13-17keV energy range. A number of additional spectral features were observed at energies lower than the helium-like n=1-3 and n=1-4 transitions. Based on computational simulations of the spectra using the FLYCHK/FLYSPEC codes, which included opacity effects, these additional features are identified to be inner-shell transitions from the Li-like through N-like krypton charge states. The comparisons of the calculated and observed spectra indicate that these transitions are characteristic of the plasma conditions immediately after the laser pulse when the krypton density is 2x10{sup 18}cm{sup -3} and the electron temperature is in the range 2.8-3.2keV. These spectral features represent a new diagnostic for the charge state distribution, the density and electron temperature, and the plasma opacity. Laboratory experiments indicate that it is feasible to record K-shell spectra from gold and higher Z targets in the >60keV energy range using a Ge(220) transmission crystal.

Accurate ab initio potential for the krypton dimer and transport properties of the low-density krypton gas.

Science.gov (United States)

Waldrop, Jonathan M; Song, Bo; Patkowski, Konrad; Wang, Xiaopo

2015-05-28

A new highly accurate potential energy curve for the krypton dimer was constructed using coupled-cluster calculations up to the singles, doubles, triples, and perturbative quadruples level, including corrections for core-core and core-valence correlation and for relativistic effects. The ab initio data points were fitted to an analytic potential which was used to compute the most important transport properties of the krypton gas. The viscosity, thermal conductivity, self-diffusion coefficient, and thermal diffusion factor were calculated by the kinetic theory at low density and temperatures from 116 to 5000 K. The comparisons with literature experimental data as well as with values from other pair potentials indicate that our new potential is superior to all previous ones. The transport property values computed in this work are recommended as standard values over the complete temperature range.

Immobilization of krypton in a metal matrix

International Nuclear Information System (INIS)

Whitmell, D.S.

1987-01-01

The report presents the work carried out on the immobilization of krypton in a metallic matrix by combined ion implantation and sputtering. The process has been successfully tested using 100 curies of fully active krypton in order to demonstrate that the process operates in the radiation levels which will be obtained with active gas at a reprocessing plant. A design study for a plant for fuel reprocessing has shown that the process can be simply operated, without requiring shielded cells. These results, which complete the development programme, indicate that the process is ideal for the containment of kripton arising from the processing of nuclear fuel and that the product will retain the gas under normal storage conditions and also during simulated accident conditions

Occlusion and storage of krypton in solids

International Nuclear Information System (INIS)

Vansant, E.F.; Thijs, A.; Peeters, G.; Bievre, P. de; Verhaert, I.

1984-01-01

The modification process in order to change in a controlled way the effective pore size of zeolites was optimized by investigating the reaction conditions such as degree of chemisorption, reaction temperature, extent of primary/secondary reactions, type of modifying agent, type of substrate, etc. Different reaction and adsorption conditions have been tested to increase the thermal stability of encapsulated krypton in modified zeolites. The possibilities for zeolite modification have been enlarged by combining boranation and silanation with a thermal treatment of sepiolite, and by the formation of boron-nitrogen compounds in zeolites. Screening experiments, on a semi-industrial scale, of the krypton removal from air were carried out. Two kinds of Kr/air separation have been tested suscessfully on modified mordenite

直接进样气相色谱-质谱法分析大气中的氪和氙%Determination of Atmospheric Krypton and Xenon by Gas Chromatography-Mass Spectrometry in Direct Injection Mode

Institute of Scientific and Technical Information of China (English)

陈占营; 刘蜀疆; 王建龙; 常印忠

2016-01-01

Volume concentration determination for atmospheric krypton and xenon is very important for krypton-85 and radioactive xenon isotopes monitoring. An injection setup integrated adjustable quantity sample injection and quantitative dilution function was designed. The effects of EI source parameters on the sensitivity of MS detector were studied. The optimized values were as following: ionization energy of 70 eV, emission current of 40 mA, cathode voltage of 27 mV, focus voltage of 85 mV and lens compensation of 20 V, respectively. A GC-MS method for the determination of krypton and xenon in atmosphere without of sample pretreatment was developed. The minimal detected concentrations for krypton and xenon were 3. 3×10-8(V/V) and 2. 6×10-9(V/V). Moreover, the krypton and xenon concentrations in the ground level air around our laboratory were measured with the results of 1 . 1 × 10-6 ( V/V ) and 9 . 3 × 10-8 ( V/V ) . The related combined standard uncertainties for krypton and xenon results were 2. 38% and 3. 15%, respectively.%大气中氪和氙体积比浓度的测量对于氪-85和放射性氙同位素监测具有重要意义。本实验设计了一套集成定量稀释功能的可调样量进样装置，对质谱检测器的工作参数进行了实验优化，确定了灯丝电离能量70 eV、灯丝发射电流40 mA、推斥极电压27 mV、离子聚焦电压85 mV和透镜补偿电压20 V等最佳工作条件。建立了空气样品直接进样条件下氪和氙的气质联用分析方法，氪和氙的最低可检测浓度分别为3.3×10-8(V/V)和2.6×10-9(V/V)。同时应用本方法测量了实验室所处开放空间大气中氪和氙的体积比浓度，分别为1.1×10-6(V/V)和9.3×10-8(V/V)，相对合成标准不确定度分别为2.38%和3.15%。

Relativistic Multichannel Treatment of Krypton Spectra across the First Ionization Threshold

Institute of Scientific and Technical Information of China (English)

QU Yi-Zhi; PENG Yong-Lun

2005-01-01

@@ The relativistic multichannel theory has been extended to calculate both the eigen quantum defects μα, transformation matrix Uiα, and the eigen dipole matrix elements Dα of krypton. The Rydberg and autoionizationspectra of krypton across the first ionization threshold are calculated within the framework of multichannel quantum defect theory. Our calculated spectra are in agreement with the absolute measurement data.

Krypton red laser photocoagulation of the ocular fundus. 1982.

Science.gov (United States)

Yannuzzi, Lawrence A; Shakin, Jeffrey L

2012-02-01

The theoretical rationale, the histopathologic evidence, and the preliminary clinical studies related to krypton red laser (KRL) photocoagulation of the ocular fundus are reviewed. The authors report on their experience with currently available laser systems using this wavelength (647.1 nm) for photocoagulation of retinal vascular proliferative diseases and chorioretinal diseases associated with exudative manifestations. A histopathologic and clinical comparison of argon blue-green laser (ABGL), the pure argon green laser (AGL), and the krypton yellow laser (KYL), with reference to photocoagulation treatment of the ocular fundus is also discussed.

Trapping of deuterium in krypton-implanted nickel

International Nuclear Information System (INIS)

Frank, R.C.; McManus, S.P.; Rehn, L.E.; Baldo, P.

1986-01-01

Krypton ions with energy 600 keV were implanted in nickel to fluences of 2 x 10 16 cm -2 under three different conditions. Deuterium was subsequently introduced into the implanted regions by electrolysis at room temperature. After the diffusible deuterium was permitted to escape, the 2 H( 3 He, 1 H) 4 He nuclear reaction was used to analyze for the trapped deuterium during an isochronal annealing program. The region implanted at 100 0 C with no higher temperature anneal had the largest number of traps; the region implanted at 100 0 C and annealed for 100 min at 500 0 C had considerably less; the region implanted at 500 0 C had the least. Electron diffraction patterns confirmed the existence of solid crystalline krypton in all three regions. Transmission electron microscope studies revealed precipitates with an average diameter of 8 nm in the region implanted at 500 0 C. The two regions implanted at 100 0 C contained smaller precipitates. Trap binding enthalpies were obtained by math modeling. In addition to the traps with binding enthalpy of 0.55 eV reported earlier by other investigators for helium implanted in nickel, a smaller number of traps with binding enthalpies up to 0.83 eV were also found. The trapping of deuterium by various types of imperfections, including the solid krypton precipitates, is discussed

Auger measurements on the two-dimensional adsorption of krypton on graphite

International Nuclear Information System (INIS)

Kramer, H.M.; Suzanne, J.

1975-01-01

The adsorption of krypton on a (0001) plane of graphite was studied by means of Auger Electron Spectroscopy. The spectrum of krypton in the energy range from 5eV to 11eV and from 30eV to 70eV is reported. By means of LEED a √3x√3 superstructure is found for the adsorbed monolayer of Kr [fr

Krypton separation from ambient air for application in collinear fast beam laser spectroscopy.

Science.gov (United States)

Mohamed, Tarek; Strohaber, James; Nava, Ricardo; Kolomenskii, Alexandre; Thonnard, Norbert; Schuessler, Hans A

2012-07-01

A portable apparatus for the separation of krypton from environmental air samples was tested. The apparatus is based on the cryogenic trapping of gases at liquid nitrogen temperature followed by controlled releases at higher temperatures. The setup consists of a liquid nitrogen trap for the removal of H(2)O and CO(2), followed by charcoal-filled coils that sequentially collect and release krypton and other gases providing four stages of gas chromatography to achieve separation and purification of krypton from mainly N(2), O(2), and Ar. Residual reactive gases remaining after the final stage of chromatography are removed with a hot Ti sponge getter. A thermal conductivity detector is used to monitor the characteristic elution times of the various components of condensed gases in the traps during step-wise warming of the traps from liquid nitrogen temperatures to 0 °C, and then to 100 °C. This allows optimizing the switching times of the valves between the stages of gas chromatography so that mainly krypton is selected and loaded to the next stage while exhausting the other gases using a He carrier. A krypton separation efficiency of ~80 % was determined using a quadrupole mass spectrometer.

Extreme-ultraviolet wavelength and lifetime measurements in highly ionized krypton

CERN Document Server

Kukla, K W; Vogt, C M V; Berry, H G; Dunford, R W; Curtis, L J; Cheng, S

2005-01-01

We have studied the spectrum of highly ionized krypton in the extreme-ultraviolet wavelength region (50-300 Aa), using beam-foil excitation of fast krypton ions at the Argonne ATLAS accelerator facility. We report measurements of transition wavelengths and excited-state lifetimes for n=2 states in the lithiumlike, berylliumlike, and boronlike ions, Kr/sup 31+,32+,33+/. Excited state lifetimes ranging from 10 ps to 3 ns were measured by acquiring time- of-flight-delayed spectra with a position-sensitive multichannel detector.

Surface temperature measurement with radioactive kryptonates

International Nuclear Information System (INIS)

Pruzinec, J.; Piatrik, M.

1976-01-01

The preparation and use of radioactive kryptonates is described for measuring surface temperatures within the region of 45 to 70 degC. Two samples each were prepared of kryptonated beechwood and hydroquinone on a paper carrier. One sample served as the standard which during the experiment was placed in a thermostat at a constant temperature of 45 degC. The second sample was placed in another thermostat where the temperature changed from 45 to 70 degC. Both samples were in the thermostat for 30 mins. The temperature was raised in steps of 2.5 degC and the time of measurement was constant in both samples. The dependences are given of the drop in activity on temperature for both types of samples. The difference was determined of the drop in activity between the standard and the second sample and the relation for measuring the temperature of the sample was determined therefrom. (J.B.)

Stripping of 1.04 MeV per nucleon krypton ions in high molecular weight vapours

International Nuclear Information System (INIS)

Eastham, D.A.; Joy, T.; Clark, R.B.; King, R.

1976-01-01

Equilibrium charge state distributions have been measured for 1.04 MeV per nucleon krypton ions in heavy vapours with molecular weights from 462 to 6500. Non-equilibrium data are presented for the heaviest vapour. A maximum increase of 0.8 in the mean charge is found relative to a conventional diatomic gas but the pressures required are two orders of magnitude less. (Auth.)

Venting krypton-85 from the Three Mile Island Unit 2 reactor building

International Nuclear Information System (INIS)

Burton, H.M.

1981-01-01

To permit the less restricted access to the reactor building necessary to maintain instrumentation and equipment, and to proceed towad the total decontamination of the facility, General Public Utilities, operators of the facility referred to hereafter as GPU, asked the United States Nuclear Regulatory Commission, or NRC, for permission to remove the 85 Kr from the reactor building by venting it to the environment. GPU supported their request with the Safety Analysis and Environmental Assessment Report on the proposed reactor building venting plan. On June 12, 1980, after seven months of licensing deliberations and numerous public hearings, the NRC granted GPU's request. The actual venting took place between June 28 and July 11, 1980. This report presents an overview of the detailed effort involved in the TMI-2 reactor building venting program. The findings reported here are condensed from a published report entitled TMI-2 Reactor Building Purge--Kr-85 Venting

Évaluation de l'incidence des programmes de transferts en espèces ...

International Development Research Centre (IDRC) Digital Library (Canada)

Les personnes qui reçoivent ces fonds doivent satisfaire à certaines conditions, comme envoyer les enfants à l'école et utiliser les services de santé de base. De récentes données laissent entendre que les transferts en espèces peuvent contribuer à une croissance favorable aux pauvres : -en servant d'outil efficace de ...

Pilot plant development for adsorptive krypton separation from dissolver off-gas

International Nuclear Information System (INIS)

Ringel, H.; Printz, R.

1987-01-01

In view of hot cell application a separation process was investigated for the retention of Kr-85 from gaseous effluents. In the flow sheet only adsorption beds are applied. The most efficient process scheme is adsorption of the noble gas on activated charcoal and thereafter separation of the coadsorbed gas species like N 2 , O 2 , Xe and CO 2 from the krypton by gas chromatography. Adsorption is at normal pressure and low temperatures of up to -160 0 C, whereas desorption is at elevated temperatures and under helium purge. Influences on the process operation like off-gas composition, adsorption temperatures and adsorbent are experimentally investigated, as well as the behavior of trace impurities in the adsorption columns. On the basis of pilot plant operation the main components for a full scale facility are being designed

High-Pressure Reactivity of Kr and F2—Stabilization of Krypton in the +4 Oxidation State

Directory of Open Access Journals (Sweden)

Dominik Kurzydłowski

2017-10-01

Full Text Available Since the synthesis of the first krypton compound, several other Kr-bearing connections have been obtained. However, in all of them krypton adopts the +2 oxidation state, in contrast to xenon which forms numerous compounds with an oxidation state as high as +8. Motivated by the possibility of thermodynamic stabilization of exotic compounds with the use of high pressure (exceeding 1 GPa = 10 kbar, we present here theoretical investigations into the chemistry of krypton and fluorine at such large compression. In particular we focus on krypton tetrafluoride, KrF4, a molecular crystal in which krypton forms short covalent bonds with neighboring fluorine atoms thus adopting the +4 oxidation state. We find that this hitherto unknown compound can be stabilized at pressures below 50 GPa. Our results indicate also that, at larger compressions, a multitude of other KrmFn fluorides should be stable, among them KrF which exhibits covalent Kr–Kr bonds. Our results set the stage for future high-pressure synthesis of novel krypton compounds.

An improved potential for krypton

International Nuclear Information System (INIS)

Aziz, R.A.

1979-01-01

An improved potential for krypton is presented. It has the simple but realistic form used by Aziz and Chen for argon based on the HFD potential suggested by Ahlrichs et.al. The potential, with known long-range behaviour, was fitted to second virial, viscosity and thermal conductivity data. The potential appears to have the best overall predictive ability for dilute gas, bulk and microscopic data. (author)

Device for separating and concentrating rare gases containing krypton gas

Energy Technology Data Exchange (ETDEWEB)

Kimura, S; Sugimoto, K

1975-06-11

In orer to highly concentrate krypton by means of adsorption and desorption of activated carbon, in a device for continuously separating and concentrating rare gases containing krypton gas by means of adsorbing and desorbing operation of activated carbon, the device includes adsorbers arranged in parallel and more than two stages of adsorbers arranged in series with the first mentioned adsorbers with the amount of activated carbon filled successively reduced, and a cooling mechanism for cooling the adsorbers when adsorbed and a heating mechanism for heating the adsorbers when desorbed.

Contribution to the study of the structure of silver krypton solid solutions

International Nuclear Information System (INIS)

Levy, V.; Tullairet, J.; Delaplace, J.; Antolin-Baudier, J.; Adda, Y.

1964-01-01

The silver-krypton solid solutions formed by electrical discharge have been studied by X-rays, electrical resistivity and electronic transmission microscopy. The crystalline parameter and residual resistivity measurements have shown that the krypton atom behaves very differently to those of other elements of the periodic classification when dissolved in silver. The recovery of the crystalline parameter and of the electrical resistivity has been studied as a function of temperature. (authors) [fr

Neutron production with mixture of deuterium and krypton in Sahand Filippov type plasma focus facility

International Nuclear Information System (INIS)

Mohammadi, M.A.; Sobhanian, S.; Rawat, R.S.

2011-01-01

This Letter reports the order of magnitude enhancement in neutron yield from Sahand plasma focus device with krypton seeded deuterium operation. The highest average neutron yield of 2.2x10 9 neutrons per shot was achieved at 1.00 Torr deuterium with 3% krypton which is higher than the best average neutron yield of 3.18x10 8 neutrons per shot for pure deuterium operation. Estimation of average neutron energy showed that the maximum and minimum average energies are 2.98±0.6 MeV at 16 kV in 0.25 Torr deuterium with 3% Kr and 2.07±0.2 MeV at 18 kV operation in 0.5 Torr deuterium with 3% Kr, respectively. The anisotropy of neutron emission from Sahand DPF showed that the neutrons are produced mainly by beam-target mechanisms. -- Highlights: → The highest average neutron yield of 2.2x10 9 neutrons per shot was achieved at mixture of deuterium and krypton. → In the krypton seeding of deuterium also anisotropy of neutron emission deuterium is found. → The krypton seeding of deuterium made the neutron emission more reliable over wider operating pressure ranges.

Transscleral contact krypton laser cyclophotocoagulation for treatment of posttraumatic glaucoma.

Science.gov (United States)

Raivio, V E; Immonen, I J; Laatikainen, L T; Puska, P M

2001-04-01

To evaluate the usefulness of the krypton laser for transscleral contact cyclophotocoagulation in the treatment of posttraumatic glaucoma. A total of 18 eyes of 18 patients with therapy-resistant posttraumatic glaucoma treated with krypton laser cyclophotocoagulation from 1991 to 1996 were included in this review. The krypton laser was delivered by a fiberoptic probe with simultaneous compression of the sclera. The energy used was 3 to 5 J per application at the tip of the probe, with an exposure time of 10 seconds. The treatment covered 90 to 360 degrees of the ciliary body with approximately 10 applications per quadrant. With one or more cyclophotocoagulation treatments, the intraocular pressure decreased from the baseline mean (+/- standard deviation) of 32.6 +/- 12.8 mm Hg to 23.6 +/- 10.3 mm Hg (n = 17) at 1 month, to 21.8 +/- 7.5 mm Hg (n = 13) at 3 months, to 22.5 +/- 7.6 mm Hg (n = 13) at 6 months, and to 19.6 +/- 10.5 mm Hg (n = 18) at the last control visit (mean, 19.4 months; range, 3 weeks to 73 months) after cyclophotocoagulation but no other glaucoma procedure. At baseline, 17 (94%) of 18 patients were taking glaucoma medication, as were 15 (83%) of 18 patients at the last control visit. One (6%) case of phthisis occurred. Krypton laser cyclophotocoagulation is an effective and reasonably well tolerated means of lowering intraocular pressure in posttraumatic glaucoma. Because of the refractory nature of the disease, repeated treatments may be needed.

Feasibility of Single Scan for Simultaneous Evaluation of Regional Krypton and Iodine Concentrations with Dual-Energy CT: An Experimental Study.

Science.gov (United States)

Hong, Sae Rom; Chang, Suyon; Im, Dong Jin; Suh, Young Joo; Hong, Yoo Jin; Hur, Jin; Kim, Young Jin; Choi, Byoung Wook; Lee, Hye-Jeong

2016-11-01

Purpose To evaluate the feasibility of a simultaneous single scan of regional krypton and iodine concentrations by using dual-energy computed tomography (CT). Materials and Methods The study was approved by the institutional animal experimental committee. An airway obstruction model was first made in 10 beagle dogs, and a pulmonary arterial occlusion was induced in each animal after 1 week. For each model, three sessions of dual-energy CT (80% krypton ventilation [krypton CT], 80% krypton ventilation with iodine enhancement [mixed-contrast agent CT], and iodine enhancement [iodine CT]) were performed. Krypton maps were made from krypton and mixed-contrast agent CT, and iodine maps were made from iodine and mixed-contrast agent CT. Observers measured overlay Hounsfield units of the diseased and contralateral segments on each map. Values were compared by using the Wilcoxon signed-rank test. Results In krypton maps of airway obstruction, overlay Hounsfield units of diseased segments were significantly decreased compared with those of contralateral segments in both krypton and mixed-contrast agent CT (P = .005 for both). However, the values of mixed-contrast agent CT were significantly higher than those of krypton CT for both segments (P = .005 and .007, respectively). In iodine maps of pulmonary arterial occlusion, values were significantly lower in diseased segments than in contralateral segments for both iodine and mixed-contrast agent CT (P = .005 for both), without significant difference between iodine and mixed-contrast agent CT for both segments (P = .126 and .307, respectively). Conclusion Although some limitations may exist, it might be feasible to analyze regional krypton and iodine concentrations simultaneously by using dual-energy CT. © RSNA, 2016.

[Effects of xenon and krypton-containing breathing mixtures on clinical and biochemical blood indices in animals].

Science.gov (United States)

Kussmaul', A R; Bogacheva, M A; Shkurat, T P; Pavlov, B N

2007-01-01

Effects of 24-hr breathing air mixtures containing xenon (XBM) and krypton (KBM) were compared in terms of hormonal status, and blood biochemical indices and morphology in laboratory animals. Some changes observed in blood and hormone indices could be a nonspecific adaptive response. Hence, we should elicit whether these effects are quickly reversible or long. For several indices krypton was a more favorable factor than xenon. However, some of its effects invite to delve into effects of different krypton concentrations on organism.

Ventilation of the deep Greenland and Norwegian seas: evidence from krypton-85, tritium, carbon-14 and argon-39

International Nuclear Information System (INIS)

Smethie, W.M. Jr.; Ostlund, H.G.; Loosli, H.H.

1986-01-01

On leg 5 of the TTO expedition, the distributions of 85 Kr, tritium, 14 C, 39 Ar, temperature, salinity, oxygen, carbon dioxide and nutrients were measured in the Greenland and Norwegian seas. These observations support previous observations that Greenland Sea Deep Water is formed by a deep convective process within the Greenland gyre. They also support AAGAARD et al.'s (1985, Journal of Geophysical Research, 90, 4833-4846) new hypothesis that Norwegian Sea Deep Water forms from a mixture of Greenland Sea Deep Water and Eurasian Basin Deep Water. Volume transports estimated from the distributions of 85 Kr, tritium, 14 C and 39 Ar range from 0.53 to 0.74 Sv for exchange between the surface and deep Greenland Sea and from 0.9 to 1.47 Sv for exchange between the deep Greenland and deep Norwegian Seas. The residence time of water and the deep Greenland Sea with respect to exchange with surface water ranges from 24 to 34 years reported by PETERSON and ROOTH (1976, Deep-Sea Research, 23, 273-283) and 35-42 years reported by BULLISTER and WEISS (1983, Science, 221, 265-268). The residence time of water in the deep Norwegian Sea with respect to exchange with the deep Greenland Sea ranges from 19 to 30 years compared to 97-107 years reported by PETERSON and ROOTH (1976) and 10-28 years reported by BULLISTER and WEISS (1983). The oxygen consumption rate was estimated to be at most 1.04 μM kg -1 y -1 for the deep Greenland Sea and to be between 0.47 and 0.79 μM kg -1 y -1 for the deep Norwegian Sea. (author)

The NA62 Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger

CERN Document Server

INSPIRE-00293812; Paoluzzi, Giovanni; Salamon, Andrea; Salina, Gaetano; Santovetti, Emanuele; Scarfi, Francesco M.; Bonaiuto, Vincenzo; Sargeni, Fausto

2012-01-01

The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K+ -> pi+ pi0 decay. To suppress this background an efficient photo veto system is foreseen. In the 1-10 mrad angular region the NA48 high performance liquid krypton electromagnetic calorimeter is used. The design, implementation and current status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger are presented.

The NA62 Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger

CERN Document Server

INSPIRE-00646848; Fucci, Adolfo; Paoluzzi, Giovanni; Salamon, Andrea; Salina, Gaetano; Santovetti, Emanuele; Scarfi, Francesco M.; Sargeni, Fausto

2011-01-01

The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to the proposed measurement is represented by the K+ -> pi+ pi0 decay. To suppress this background an efficient photo veto system is foreseen. In the 1-10 mrad angular region the NA48 high performance liquid krypton electromagnetic calorimeter is used. The design, implementation and current status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger are presented.

Range distributions in multiply implanted targets

International Nuclear Information System (INIS)

Kostic, S.; Jimenez-Rodriguez, J.J.; Karpuzov, D.S.; Armour, D.G.; Carter, G.; Salford Univ.

1984-01-01

Range distributions in inhomogeneous binary targets have been investigated both theoretically and experimentally. Silicon single crystal targets [(111) orientation] were implanted with 40 keV Pb + ions to fluences in the range from 5x10 14 to 7.5x10 16 cm -2 prior to bombardment with 80 keV Kr + ions to a fluence of 5x10 15 cm -2 . The samples were analysed using high resolution Rutherford backscattering before and after the krypton implantation in order to determine the dependence of the krypton distribution on the amount of lead previously implanted. The theoretical analysis was undertaken using the formalism developed in [1] and the computer simulation was based on the MARLOWE code. The agreement between the experimental, theoretical and computational krypton profiles is very good and the results indicate that accurate prediction of ranges profiles in inhomogeneous binary targets is possible using available theoretical and computational treatments. (orig.)

Allocation universelle et transferts "ELIE" : De la divergence à la compatibilité ?

OpenAIRE

Claude Gamel

2008-01-01

Van Parijs (1995) and Kolm (2005) étudient les fondements éthico-philosophiques de la fiscalité et de la redistribution des revenus à travers les projets apparemment proches d'allocation universelle et de transferts ELIE (1). En fait, les deux propositions divergent en raison de modalités plus ou moins crédibles de financement et du traitement très dissemblable des « excentriques productifs » qui choisissent de ne pas travailler (2). Les deux projets restent néanmoins compatibles : du point d...

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. II

International Nuclear Information System (INIS)

Harangozo, M.; Jombik, J.; Schiller, P.; Toelgyessy, J.

1981-01-01

A method for the determination of citric, tartaric and undecylenic acids based on radiometric titration with 0.1 or 0.05 mole.l -1 NaOH was developed. As an indicator of the end point, radioactive kryptonate of glass was used. Experimental technique, results of determinations as well as other possible applications of the radioactive kryptonate of glass for end point determination in alkalimetric analyses of officinal pharmaceuticals are discussed. (author)

The mutual influence of krypton implantation and pre-existing stress states in polycrystalline alpha titanium

Energy Technology Data Exchange (ETDEWEB)

Nsengiyumva, S. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa); Department of Physics, Kigali Institute of Education, P.O. Box 5039 Kigali (Rwanda)], E-mail: schadrack.nsengiyumva@uct.ac.za; Ntsoane, T.P. [Nuclear Energy Corporation of South Africa (NECSA), P.O. Box 582 (South Africa); Raji, A.T. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa); Topic, M. [iThemba LABS, Somerset West 7129 (South Africa); Kellermann, G. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas (Brazil); Riviere, J.P. [Laboratoire de Physique des Materiaux UMR6630-CNRS, 86960 (France); Britton, D.T.; Haerting, M. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa)

2009-08-15

The stress profile in polycrystalline titanium implanted with krypton ions at different fluences has been determined using synchrotron radiation diffraction. For each fluence, the krypton profile has been measured using Rutherford backscattering geometry. The results were compared to model calculations obtained from the SRIM 2008 computer code. A strong stress relaxation was found for high fluence implantation, whereas for low fluence implantation an additional source of tensile stress was introduced in the near surface region. The projected range of the implanted krypton was significantly reduced compared to the expected range. A possible cause of this discrepancy is the drift of implanted ions under the influence of the pre-existing stress gradient.

The mutual influence of krypton implantation and pre-existing stress states in polycrystalline alpha titanium

International Nuclear Information System (INIS)

Nsengiyumva, S.; Ntsoane, T.P.; Raji, A.T.; Topic, M.; Kellermann, G.; Riviere, J.P.; Britton, D.T.; Haerting, M.

2009-01-01

The stress profile in polycrystalline titanium implanted with krypton ions at different fluences has been determined using synchrotron radiation diffraction. For each fluence, the krypton profile has been measured using Rutherford backscattering geometry. The results were compared to model calculations obtained from the SRIM 2008 computer code. A strong stress relaxation was found for high fluence implantation, whereas for low fluence implantation an additional source of tensile stress was introduced in the near surface region. The projected range of the implanted krypton was significantly reduced compared to the expected range. A possible cause of this discrepancy is the drift of implanted ions under the influence of the pre-existing stress gradient.

Dynamique de transfert des matières organiques et inorganiques le long du continuum fluvial de la Garonne : impact de la retenue de Malause

OpenAIRE

Mamoudou, Mohamadou

2008-01-01

Les fleuves sont à l'origine des transferts de matières organiques et inorganiques des continents vers les océans. Ces matières peuvent être séparées par filtration (généralement à 0,45 ou 0,22µm) entre une phase particulaire et une phase dissoute. Le devenir des formes organiques va dépendre de leurs origines. Les formes labiles sont souvent rapidement minéralisées lors de leur transfert tandis que les formes réfractaires ont un comportement conservatif. Nous avons étudié la dynamique de tou...

Bonding xenon and krypton on the surface of uranium dioxide single crystal

Directory of Open Access Journals (Sweden)

Dąbrowski Ludwik

2014-08-01

Full Text Available We present density functional theory (DFT calculation results of krypton and xenon atoms interaction on the surface of uranium dioxide single crystal. A pseudo-potential approach in the generalised gradient approximation (GGA was applied using the ABINIT program package. To compute the unit cell parameters, the 25 atom super-cell was chosen. It has been revealed that close to the surface of a potential well is formed for xenon and krypton atom due to its interaction with the atoms of oxygen and uranium. Depth and shape of the well is the subject of ab initio calculations in adiabatic approximation. The calculations were performed both for the case of oxygenic and metallic surfaces. It has been shown that the potential well for the oxygenic surface is deeper than for the metallic surface. The thermal stability of immobilising the atoms of krypton and xenon in the potential wells were evaluated. The results are shown in graphs.

Dielectronic recombination and resonant transfer excitation processes for helium-like krypton

Institute of Scientific and Technical Information of China (English)

Hu Xiao-Li; Qu Yi-Zhi; Zhang Song-Bin; Zhang Yu

2012-01-01

The relativistic configuration interaction method is employed to calculate the dielectronic recombination (DR) cross sections of helium-like krypton via the 1s21nl' (n =2,3,...,15) resonances.Then,the resonant transfer excitation (RTE) processes of Kr34+ colliding with H,He,H2,and CHx (x =0-4) targets are investigated under the impulse approximation.The needed Compton profiles of targets are obtained from the Hartree-Fock wave functions.The RTE cross sections are strongly dependent on DR resonant energies and strengths,and the electron momentum distributions of the target.For H2 and H targets,the ratio of their RTE cross sections changes from 1.85 for the 1s2121' to 1.88 for other resonances,which demonstrates the weak molecular effects on the Compton profiles of H2.For CHx (x =0-4) targets,the main contribution to the RTE cross section comes from the carbon atom since carbon carries 6 electrons;as the number of hydrogen increases in CHx,the RTE cross section almost increases by the same value,displaying the strong separate atom character for the hydrogen.However,further comparison of the individual orbital contributions of C(2p,2s,ls) and CH4(1t2,2a1,1a1) to the RTE cross sections shows that the molecular effects induce differences of about 25.1％,19.9％,and 0.2％ between 2p-1t2,2s-2a1,and 1s-1a1 orbitals,respectively.

Particle dynamics during electronic sputtering of solid krypton

DEFF Research Database (Denmark)

Dutkiewicz, L.; Pedrys, R.; Schou, Jørgen

1995-01-01

We have modeled electronic sputtering of solid krypton by excimer production with molecular dynamics. Both excimer evolution in the solid and deexcitation processes have been incorporated in the simulation. The excimer dynamics in the lattice has been analyzed: the excimers formed near the surface...

The place of krypton-81m ventilation in the scintigraphic investigation of the lung

International Nuclear Information System (INIS)

Hoefnagel, C.A.; Marcuse, H.R.

1983-01-01

Fairly recently krypton-81m gas became available for diagnostic purposes. Its advantages and ways to use are surveyed especially for the diagnosis of lung emboli and lung diseases. The combination of perfusion and ventilation scintigrams is the best for specifying the diagnosis. Krypton-81m gas improves the specificity and sensitivity of the examination which is non-invasive and carries no burden for the patient. (Auth.)

Oxygen sensitivity of krypton and Lyman-alpha hygrometers

NARCIS (Netherlands)

Dijk, van A.; Kohsiek, W.; Bruin, de H.A.R.

2003-01-01

The oxygen sensitivity of krypton and Lyman-¿ hygrometers is studied. Using a dewpoint generator and a controlled nitrogen/oxygen flow the extinction coefficients of five hygrometers associated with the third-order Taylor expansion of the Lambert¿Beer law around reference conditions for oxygen and

Status of the NA62 liquid krypton electromagnetic calorimeter Level 0 trigger processor

CERN Document Server

Bonaiuto, V; Fucci, A; Paoluzzi, G; Salamon, A; Salina, G; Santovetti, E; Sargeni, F; Venditti, S

2013-01-01

The NA62 experiment at the CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K(+)→π(+)νbar nu collecting O(100) events with a 10% background in two years of data taking. To reject the K(+)→π(+)π(0) background the NA48 liquid krypton calorimeter will be used in the 1-10 mrad angular region. The status of the Liquid Krypton Electromagnetic Calorimeter Level 0 Trigger is presented.

Radiation protection problems in using krypton 81 m in pulmonary ventilation scintiscanning

International Nuclear Information System (INIS)

Spesshardt, K.

1982-01-01

The experience gained in using the krypton-81 generator as regards radiation protection is briefly outlined by means of measurements, carried through in the framework of the operation licensing procedure. It turned out that while krypton is a very helpful substance in clinical investigations on account of its favourable gamma energy and very short half-life, it does create some radiation protection problems. The radiation protection measures carried through at the inhalation system can be described as satisfactory. Improvements are due at the filter system between generator and breathing mask. (orig./DG) [de

X-ray spectroscopic measurements of dielectronic recombination of highly charged krypton ions

International Nuclear Information System (INIS)

Biedermann, C.; Fuchs, T.; Liebisch, P.; Radtke, R.; Behar, E.; Doron, R.

1999-01-01

We have performed X-ray spectroscopic measurements of the dielectronic recombination (DR) resonance strengths for the KLn (n = 2, .., 5) series of He-, Li-, and Be-like krypton ions. The ions were produced with an electron beam ion trap, and the strengths were obtained from a fit procedure that compares the experimental excitation function for DR to theory. The results agree well with the predictions. By looking at the KLL resonance, the time evolution of different krypton charge states was measured with this technique and compared with a model of the trap inventory. (orig.)

Experimental Investigations of a Krypton Stationary Plasma Thruster

Directory of Open Access Journals (Sweden)

A. I. Bugrova

2013-01-01

Full Text Available Stationary plasma thrusters are attractive electric propulsion systems for spacecrafts. The usual propellant is xenon. Among the other suggested propellants, krypton could be one of the best candidates. Most studies have been carried out with a Hall effect thruster previously designed for xenon. The ATON A-3 developed by MSTU MIREA (Moscow initially defined for xenon has been optimized for krypton. The stable high-performance ATON A-3 operation in Kr has been achieved after optimization of its magnetic field configuration and its optimization in different parameters: length and width of the channel, buffer volume dimensions, mode of the cathode operation, and input parameters. For a voltage of 400 V and the anode mass flow rate of 2.5 mg/s the anode efficiency reaches 60% and the specific impulse reaches 2900 s under A-3 operating with Kr. The achieved performances under operation A-3 with Kr are presented and compared with performances obtained with Xe.

Energy-momentum structure of the krypton valence shell by electron-momentum spectroscopy

International Nuclear Information System (INIS)

Nicholson, R.; Braidwood, S.W.; McCathy, I.E.; Weigold, E.; Brunger, M.J.

1996-03-01

Momentum distributions and spectroscopic factors are obtained in a high resolution electron-momentum spectroscopy study of krypton at 1000 eV. The shapes and relative magnitudes of the momentum profiles are in good agreement with the results of calculations made within the distorted-wave impulse approximation (DWIA) framework. The DWIA describes the relative magnitudes of the 4p and 4s manifolds as well as giving a good representation of the shapes of the respective 4p and 4s cross sections. Results for the momentum profiles belonging to excited 2 P o and 2 S e manifolds are also presented. Spectroscopic factors for transitions belonging to the 2 p o and 2 S e manifolds are assigned up to a binding energy of 42 eV. The spectroscopic factor for the lowest 4s transition is 0.51 ± 0.01, whereas that for the ground-state 4p transition is 0.98± 0.01. Comparisons of the present binding energies and spectroscopic factors are made against the results of several many-body calculations and photoelectron spectroscopy (PES) results. In addition, a new procedure is outlined, utilising the experimental 4p and 4s manifold cross sections, that provides information on possible initial state configuration interaction effects in krypton. 50 refs., 2 tabs., 10 figs

Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

Science.gov (United States)

Oliveira, M. H.; Viana, G. A.; de Lima, M. M.; Cros, A.; Cantarero, A.; Marques, F. C.

2010-12-01

Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH4) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

Influence of krypton atoms on the structure of hydrogenated amorphous carbon deposited by plasma enhanced chemical vapor deposition

International Nuclear Information System (INIS)

Oliveira, M. H. Jr.; Viana, G. A.; Marques, F. C.; Lima, M. M. Jr. de; Cros, A.; Cantarero, A.

2010-01-01

Hydrogenated amorphous carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition using methane (CH 4 ) plus krypton (Kr) mixed atmosphere. The depositions were performed as function of the bias voltage and krypton partial pressure. The goal of this work was to study the influence of krypton gas on the physical properties of a-C:H films deposited on the cathode electrode. Krypton concentration up to 1.6 at. %, determined by Rutherford Back-Scattering, was obtained at high Kr partial pressure and bias of -120 V. The structure of the films was analyzed by means of optical transmission spectroscopy, multi-wavelength Raman scattering and Fourier Transform Infrared spectroscopy. It was verified that the structure of the films remains unchanged up to a concentration of Kr of about 1.0 at. %. A slight graphitization of the films occurs for higher concentration. The observed variation in the film structure, optical band gap, stress, and hydrogen concentration were associated mainly with the subplantation process of hydrocarbons radicals, rather than the krypton ion energy.

Radioactive tracer system to indicate drill bit wear or failure

International Nuclear Information System (INIS)

Fries, B.A.

1975-01-01

A radioactive tracer system for indicating drill bit wear or failure utilizing radioactive krypton 85 in clathrate form, in the form of water-soluble kryptonates, or dissolved grease, is described. Preferably the radioactive krypton is placed so that when drill bit wear or failure occurs, the radioactive krypton 85 is relased and effectively becomes diffused in the circulating drilling fluid. At the surface, the radioactive krypton 85 gas is separated from the circulating drilling fluid by gas-mud separating means and is transported as a gas to a counting chamber where an accurate radioactivity count of beta rays released from the krypton is obtained. (Patent Office Record)

Analysis of HARP TPC krypton data

CERN Document Server

Dydak, F

2004-01-01

This memo describes the procedure which was adopted to equalize the response of the 3972 pads of the HARP TPC, using radioactive 83mKr gas. The results obtained from the study of reconstructed krypton clusters in the calibration data taken in 2002 are reported. Two complementary methods were employed in the data analysis. Compatible results were obtained for channel-to-channel equalization constants. An estimate of the overall systematic uncertainty was derived.

Iridotomy with red krypton laser.

Science.gov (United States)

Yassur, Y; David, R; Rosenblatt, I; Marmour, U

1986-01-01

Iridotomy with red krypton laser instead of blue-green argon laser was performed on 68 eyes with various types of angle-closure glaucoma. Patent iridotomy was obtained in all the eyes, mostly in one working session. In eight eyes secondary closure by pigment needed reopening with a few applications at the iridotomy site. There were no immediate or late complications of importance, the main advantage of the technique being the avoidance of the corneal epithelial and endothelial burns which commonly occur during argon laser iridotomy, particularly when the anterior chamber is shallow. PMID:3964628

Thermophysical properties of krypton-helium gas mixtures from ab initio pair potentials.

Science.gov (United States)

Jäger, Benjamin; Bich, Eckard

2017-06-07

A new potential energy curve for the krypton-helium atom pair was developed using supermolecular ab initio computations for 34 interatomic distances. Values for the interaction energies at the complete basis set limit were obtained from calculations with the coupled-cluster method with single, double, and perturbative triple excitations and correlation consistent basis sets up to sextuple-zeta quality augmented with mid-bond functions. Higher-order coupled-cluster excitations up to the full quadruple level were accounted for in a scheme of successive correction terms. Core-core and core-valence correlation effects were included. Relativistic corrections were considered not only at the scalar relativistic level but also using full four-component Dirac-Coulomb and Dirac-Coulomb-Gaunt calculations. The fitted analytical pair potential function is characterized by a well depth of 31.42 K with an estimated standard uncertainty of 0.08 K. Statistical thermodynamics was applied to compute the krypton-helium cross second virial coefficients. The results show a very good agreement with the best experimental data. Kinetic theory calculations based on classical and quantum-mechanical approaches for the underlying collision dynamics were utilized to compute the transport properties of krypton-helium mixtures in the dilute-gas limit for a large temperature range. The results were analyzed with respect to the orders of approximation of kinetic theory and compared with experimental data. Especially the data for the binary diffusion coefficient confirm the predictive quality of the new potential. Furthermore, inconsistencies between two empirical pair potential functions for the krypton-helium system from the literature could be resolved.

High-Power Krypton Hall Thruster Technology Being Developed for Nuclear-Powered Applications

Science.gov (United States)

Jacobson, David T.; Manzella, David H.

2004-01-01

The NASA Glenn Research Center has been performing research and development of moderate specific impulse, xenon-fueled, high-power Hall thrusters for potential solar electric propulsion applications. These applications include Mars missions, reusable tugs for low-Earth-orbit to geosynchronous-Earth-orbit transportation, and missions that require transportation to libration points. This research and development effort resulted in the design and fabrication of the NASA-457M Hall thruster that has been tested at input powers up to 95 kW. During project year 2003, NASA established Project Prometheus to develop technology in the areas of nuclear power and propulsion, which are enabling for deep-space science missions. One of the Project-Prometheus-sponsored Nuclear Propulsion Research tasks is to investigate alternate propellants for high-power Hall thruster electric propulsion. The motivation for alternate propellants includes the disadvantageous cost and availability of xenon propellant for extremely large scale, xenon-fueled propulsion systems and the potential system performance benefits of using alternate propellants. The alternate propellant krypton was investigated because of its low cost relative to xenon. Krypton propellant also has potential performance benefits for deep-space missions because the theoretical specific impulse for a given voltage is 20 percent higher than for xenon because of krypton's lower molecular weight. During project year 2003, the performance of the high-power NASA-457M Hall thruster was measured using krypton as the propellant at power levels ranging from 6.4 to 72.5 kW. The thrust produced ranged from 0.3 to 2.5 N at a discharge specific impulse up to 4500 sec.

The effect of annealing unimplanted and krypton implanted uranium dioxide using positrons

International Nuclear Information System (INIS)

Evans, H.E.; Rice-Evans, P.; Smith, D.L.; Smith, C.; Evans, J.H.

1992-01-01

Previous studies examining the response of variable energy positrons to metals implanted with krypton ions have been extended to UO 2 . The behaviour of two Kr-implanted samples (one implanted at 300 K, the other at 870 K) during annealing up to 1350 K has been followed, together with an unimplanted, as-polished sample. There are several features of interest in the results although in these initial studies the interpretation is not always clear. Defect recovery and krypton effects can be identified but at high temperatures some suggestion of a sensitivity of positrons to stoichiometry is present

The NA48 liquid krypton calorimeter

CERN Document Server

Gorini, B

1997-01-01

The NA48 collaboration goal is to measure the CP violation parameter Re(ɛl/ɛ) at the level of 2 × 10−4. The neutral Kaon decays will be reconstructed by an electromagnetic liquid Krypton calorimeter with fine granularity and a volume almost totally sensible, to obtain excellent position and energy resolution, as well as time resolution. A description of the detector, results from tests of a prototype and the status of the final calorimeter are reported.

Answers to questions about removing krypton from the Three Mile Island, Unit 2 reactor building. Public information report

International Nuclear Information System (INIS)

1980-05-01

This document presents answers to frequently asked questions about the probable effects of controlled releases of the krypton presently contained within the reactor building of Three Mile Island, Unit 2. Also answered are questions about alternative means for removing the krypton

Krypton separation from waste gas of a reprocessing plant by low temperature rectification

International Nuclear Information System (INIS)

1987-01-01

6 lectures at this seminar describe and evaluate the results of the research and development work on low temperature krypton separation from the waste gas of the reprocessing of nuclear fuels. They are used for making decisions for the process to be used in the future on a large scale at the Wackersdorf reprocessing plant. 2 further lectures deal with alternatives to this process, which were also developed: the freon washing and low temperature adsorption of krypton. All the lectures were included separately in the INIS and ENERGY databases. (RB) [de

Device for purifying exhaust gas

International Nuclear Information System (INIS)

Makita, Kiyoshi.

1973-01-01

Purpose: To ensure the reliability in collection of krypton even on accident in liquidizing distillation tower. Constitution: Exhaust gas flows through active carbon adsorption tower where short half-life rare gas in exhaust gas is separated by adsorption, then through heat exchanger, then continuous distillation tower where krypton 85 is separated, then through batch distillation tower where krypton 85 is condensed, and then flows into storing cylinder. On accident in liquidizing distillation tower, at the first period exhaust gas flows through series connected active carbon adsorption tower, krypton 85 adsorbed in adsorption tower being transferred to cooling type adsorption tower, at the next period exhaust gas flows through tower, krypton 85 adsorbed in adsorption tower being transferred to tower. (M. K.)

Comparison in the analytical performance between krypton and argon glow discharge plasmas as the excitation source for atomic emission spectrometry.

Science.gov (United States)

Wagatsuma, Kazuaki

2009-04-01

The emission characteristics of ionic lines of nickel, cobalt, and vanadium were investigated when argon or krypton was employed as the plasma gas in glow discharge optical emission spectrometry. A dc Grimm-style lamp was employed as the excitation source. Detection limits of the ionic lines in each iron-matrix alloy sample were compared between the krypton and the argon plasmas. Particular intense ionic lines were observed in the emission spectra as a function of the discharge gas (krypton or argon), such as the Co II 258.033 nm for krypton and the Co II 231.707 nm for argon. The explanation for this is that collisions with the plasma gases dominantly populate particular excited levels of cobalt ion, which can receive the internal energy from each gas ion selectively, for example, the 3d(7)4p (3)G(5) (6.0201 eV) for krypton and the 3d(7)4p (3)G(4) (8.0779 eV) for argon. In the determination of nickel as well as cobalt in iron-matrix samples, more sensitive ionic lines could be found in the krypton plasma rather than the argon plasma. Detection limits in the krypton plasma were 0.0039 mass% Ni for the Ni II 230.299-nm line and 0.002 mass% Co for the Co II 258.033-nm line. However, in the determination of vanadium, the argon plasma had better analytical performance, giving a detection limit of 0.0023 mass% V for the V II 309.310-nm line.

Experimental study of X-ray emission yield in a Filippov-type Plasma Focus operating in neon and neon-krypton mixture

International Nuclear Information System (INIS)

Babazadeh, A.R.; Kiai, S.M.S.; Roshan, M.V.; Emami, M.

2002-01-01

Since the installation of PF-DENA at AEOI about one year ago, we performed quantitative studies of variation of X-ray radiations from a new Filippov-type plasma focus device: Dena (90 kJ, 25 kV, 288 μF). The operating gas was neon at a constant pressure of 1 torr and different pressures of krypton admixture (up to 0.3 torr), with the discharge voltage up to 18 kV. For charging voltage of 17 kV with 41 kJ stored energy and spark gap pressure of 1.2x 10 -2 torr, the maximum soft and little hard X-ray (SXR-HXR) emission is found for the neon, resulting in a total SXR yield of 2 V/shot measured by silicon semiconductor diode detectors. Concerning the effect of krypton admixture, a maximum intensity of SXR radiation has been observed at low krypton pressure that is about 1 V/shot. At higher pressure, the quality of SXR emission decreases down to zero. However, the maximum intensity of the HXR radiation yield in the same pressure range was found to be 2.5 V/shot. By increasing the pressure of krypton up tp 0.3 torr, the results show that the krypton admixture gas generally causes, a decrease of the SXR radiation yield down to zero, whereas, the HXR emission yield carries a maximum value at the optimum pressure of krypton that is about 0.1 torr. Nevertheless, the pressure increments of krypton lead to decreasing in the discharge voltage for the maximum X-ray production. (author)

Separation of krypton from dissolver off-gas of a reprocessing plant using preparative gas chromatography

International Nuclear Information System (INIS)

Matoni, M.

1984-02-01

Kr-85 can be separated from the pre-purified purge air in the final processing step of the purification phase for dissolver off-gases of a reprocessing plant with the aid of preparative gas chromatography. Activated carbon adsorbers in combination with helium as carrier gas permits maximum gas mixture through-flow. A separation temperature of 30 0 C is considered optimal. An adsorbent volume of 40 dm 3 is necessary for processing the residual gas flow of 2.5 Nm 3 /h; the adsorbent is divided between 2 columns linked in series each of which are 2 m long with an internal diameter of 100 mm. The helium flow required is five times greater than the off-gas flow. The degree of purity for krypton is greater than 90% for a decontamination factor of greater than 1000. (orig./HP) [de

In Situ Measurement of Atmospheric Krypton and Xenon on Mars with Mars Science Laboratory

Science.gov (United States)

Conrad, P. G.; Malespin, C. A.; Franz, H. B.; Pepin, R. O.; Trainer, M. G.; Schwenzer, S. P.; Atreya, S. K.; Freissinet, C.; Jones, J. H.; Manning, H.;

State-of-the-art ab initio potential energy curve for the krypton atom pair and thermophysical properties of dilute krypton gas.

Science.gov (United States)

Jäger, Benjamin; Hellmann, Robert; Bich, Eckard; Vogel, Eckhard

2016-03-21

A new reference krypton-krypton interatomic potential energy curve was developed by means of quantum-chemical ab initio calculations for 36 interatomic separations. Highly accurate values for the interaction energies at the complete basis set limit were obtained using the coupled-cluster method with single, double, and perturbative triple excitations as well as t-aug-cc-pV5Z and t-aug-cc-pV6Z basis sets including mid-bond functions, with the 6Z basis set being newly constructed for this study. Higher orders of coupled-cluster terms were considered in a successive scheme up to full quadruple excitations. Core-core and core-valence correlation effects were included. Furthermore, relativistic effects were studied not only at a scalar relativistic level using second-order direct perturbation theory, but also utilizing full four-component and Gaunt-effect computations. An analytical pair potential function was fitted to the interaction energies, which is characterized by a depth of 200.88 K with an estimated standard uncertainty of 0.51 K. Thermophysical properties of low-density krypton were calculated for temperatures up to 5000 K. Second and third virial coefficients were obtained from statistical thermodynamics. Viscosity and thermal conductivity as well as the self-diffusion coefficient were computed using the kinetic theory of gases. The theoretical results are compared with experimental data and with results for other pair potential functions from the literature, especially with those calculated from the recently developed ab initio potential of Waldrop et al. [J. Chem. Phys. 142, 204307 (2015)]. Highly accurate experimental viscosity data indicate that both the present ab initio pair potential and the one of Waldrop et al. can be regarded as reference potentials, even though the quantum-chemical methods and basis sets differ. However, the uncertainties of the present potential and of the derived properties are estimated to be considerably lower.

Generalized oscillator strengths for some higher valence-shell excitations of krypton atom

Institute of Scientific and Technical Information of China (English)

2007-01-01

The valence-shell excitations of krypton atom have been investigated by fast electron impact with an angle-resolved electron-energy-loss spectrometer. The generalized oscillator strengths for some higher mixed valence-shell excitations in 4d, 4f, 5p, 5d, 6s, 6p, 7s ← 4p of krypton atom have been determined. Their profiles are discussed, and the generalized oscillator strengths for the electric monopole and quadrupole excitations in 5p ← 4p are compared with the calculations of Amusia et al. (Phys. Rev. A 67 022703 (2003)). The differences between the experimental results and theoretical calculations show that more studies are needed.

Interdiffusion of krypton and xenon in high-pressure helium

International Nuclear Information System (INIS)

Campana, R.J.; Jensen, D.D.; Epstein, B.D.; Hudson, R.G.; Baldwin, N.L.

1980-01-01

The interdiffusion of gaseous fission products in high-pressure helium is an important factor in the control of radioactivity in gas-cooled fast breeder reactors (GCFRs). As presently conceived, GCFRs use pressure-equalized and vented fuel in which fission gases released from the solid matrix oxide fuel are transported through the fuel rod interstices and internal fission product traps to the fuel assembly vents, where they are swept away to external traps and storage. Since the predominant transport process under steady-state operating conditions is interdiffusion of gaseous fission products in helium, the diffusion properties of krypton-helium and xenon-helium couples have been measured over the range of GCFR temperature and pressure conditions ( -1 ) and expected temperature dependence to the 1.66 power (Tsup(1.66)) at lower pressures and temperatures. Additional work is in progress to measure the behaviour of the krypton-helium and xenon-helium couples in GCFR fuel rod charcoal delay traps. (author)

Etude du transfert de pesticides dans les sols Exemple de divers herbicides organiques de synthèse et d'un produit minéral : le cuivre

OpenAIRE

DOUSSET , Sylvie

2005-01-01

Ce mémoire présente une synthèse de mes activités scientifiques depuis 1994 en matière de transferts de pesticides, et plus spécifiquement d’herbicides dans les sols. En guise d’introduction, je présenterai la problématique, la réglementation en matière de pesticides et des généralités sur leurs transferts. La première partie de ce travail, la plus volumineuse, correspond aux diverses échelles auxquelles il est possible d’étudier le lessivage des pesticides dans les sols ; les exemples sont c...

Krypton laser membranotomy in the treatment of dense premacular hemorrhage.

Science.gov (United States)

Chen, Yung-Jen; Kou, His-Kung

2004-12-01

Neodymium:YAG (Nd:YAG) laser and argon laser membranotomy have been used in patients with premacular hemorrhage to drain premacular blood into the vitreous cavity and rapidly clear the hemorrhage. However, the Nd:YAG laser appears to be difficult to use, and argon laser energy may be more likely to be absorbed by the ocular media. We performed a study to evaluate the safety and effectiveness of krypton laser membranotomy in selected cases of premacular hemorrhage. Sixteen patients (17 eyes) with dense premacular hemorrhage for 2 weeks or less were enrolled from April 1998 to February 2004. The causes of premacular hemorrhage were proliferative diabetic retinopathy (PDR) in 12 eyes, Valsalva retinopathy in 3 eyes, leukemia in I eye and retinal arterial macroaneurysm in I eye. Krypton laser was used to create a membranotomy on the sloping edge of the premacular hemorrhage. Five eyes with PDR were treated with inferior panretinal photocoagulation and laser membranotomy simultaneously. After intravitreal dispersion of premacular blood, fundus examination was performed in all eyes and fluorescein angiography in five eyes to evaluate retinal damage. All eyes had visual improvement within 2 weeks postoperatively. No retinal damage was seen at the site of membranotomy in any eye. No eye needed vitrectomy postoperatively during a mean follow-up duration of 18.6 months. Krypton laser membranotomy appears to be a safe and simple alternative procedure for treating selected cases of premacular hemorrhage. Further trials are necessary to evaluate its benefit.

S-process krypton of variable isotopic composition in the Murchison meteorite

Science.gov (United States)

Ott, Urlich; Begemann, Friedrich; Yang, Yongmann; Epstein, Samuel

1988-01-01

Data are reported which, for the first time, permit the derivation of the full isotopic spectrum of s-process krypton with reasonable precision. It is shown that this s-Kr in a residue from the Murchison meteorite did not originate in one single s-process but rather is a mixture of contributions from stellar environments where the density of free neutrons was not the same. The astrophysical conditions under which this krypton was produced were distinct from those that have been invoked to explain the solar system s-process abundance. Similar to the C-13-rich carbon component in an aliquot of the same residue, the s-process Kr from different astrophysical sites has retained its identity during the accumulation and subsequent history of the meteorite.

S-process krypton of variable isotopic composition in the Murchison meteorite

International Nuclear Information System (INIS)

Ott, U.; Begemann, F.; Yang, J.; Epstein, S.

1988-01-01

We report data that allow us to derive with reasonable precision the full isotopic spectrum of s-process krypton. We show that this s-Kr in a residue from Murchison meteorite did not originate in one single s-process but rather is a mixture of contributions from stellar environments where the density of free neutrons was not the same. The astrophysical conditions under which this krypton has been produced were distinct from those that have been invoked to explain the Solar System s-process abundance. Similar to the 13 C-rich carbon component in an aliquot of the same residue, the s-process Kr from different astrophysical sites has retained its identify during the accumulation and subsequent history of the meteorite. (author)

Determination of SO2 in the atmosphere using radioactive iodine kryptonate as impregnation medium of chromatographic paper

International Nuclear Information System (INIS)

Pruzinec, J.

1975-01-01

Chromatographic paper was impregnated with radioiodine kryptonate using the macrodiffusion technique. The decrease with time of the activity of the kryptonate-impregnated paper exposed to SO 2 -contaminated air was measured. From the decrease in chromatographic paper activity, the concentration of SO 2 was determined in the range 300 to 700 ppm. (A.K.)

Measurement of the radiative cooling rates for high-ionization species of krypton using an electron beam ion trap

International Nuclear Information System (INIS)

Radtke, R.; Biedermann, C.; Fuchs, T.; Fussmann, G.; Beiersdorfer, P.

2000-01-01

We describe a measurement of the radiative cooling rate for krypton made at the Berlin electron beam ion trap (EBIT). The EBIT was tuned to a charge-state distribution approaching the ionization balance of a plasma at a temperature of about 5 keV. To determine the cooling rate, we made use of EBIT's capabilities to sample a wide range of electron-beam energies and distinguish between different radiation channels. We have measured the x-ray emission from bremsstrahlung, radiative recombination, dielectronic recombination, and line radiation following electron-impact excitation. The dominant contribution to the cooling rate is made by the n=3-2, n=4-2,... x rays of the L-shell spectra of krypton, which produce more than 75% of the total radiation loss. A difference with theoretical calculations is noted for the measured total cooling rate. The predicted values are lower by a factor of 1.5-2, depending on the theoretical model. For our measurement of the cooling rate, we estimate an uncertainty interval of 22-30 %. (c) 2000 The American Physical Society

Design and performance characteristics of a krypton chloride (λ ...

Indian Academy of Sciences (India)

2014-01-07

Jan 7, 2014 ... Development of a discharge-pumped krypton chloride (KrCl) laser operating at 222 nm wavelength is demonstrated. In this paper the design, successful realization and operating characteristics of KrCl excimer laser are reported. The laser is driven by a simple and efficient excitation technique using ...

Experimental studies on the krypton absorption in liquid CO2 (KALC) process

International Nuclear Information System (INIS)

Glass, R.W.; Beaujean, H.W.R.; Fowler, V.L.; Gilliam, T.M.; Inman, D.J.; Levins, D.M.

1976-01-01

Results are presented for a series of experiments to quantify krypton removal from simulated High-Temperature Gas-Cooled Reactor reprocessing off-gas by the KALC process. The Experimental Engineering Section Off-Gas Decontamination Facility used in the campaign provides engineering-scale experiments with nominal gas and liquid flows of 5 scfm and 0.5 gpm respectively. Equilibrium and nonequilibrium mass transfer experiments for the CO 2 --O 2 --Kr system are described. Data analysis indicates values of HTU for krypton on the order of 0.5 ft for decontamination factors from 100 to 10,000. Recent flooding information for the packed columns is combined with previous data and is shown to be well represented by an empirical flooding equation

85 km Long Reach PON System Using a Reflective SOA-EA Modulator and Distributed Raman Fiber Amplification

DEFF Research Database (Denmark)

Tafur Monroy, Idelfonso; Öhman, Filip; Yvind, Kresten

2006-01-01

We report on a bidirectional 85 km long reach PON system supported by distributed fiber Raman amplification with a record 7.5 Gb/s remote carrier modulated upstream signal by employing a reflective SOA-EA monolithically integrated circuit......We report on a bidirectional 85 km long reach PON system supported by distributed fiber Raman amplification with a record 7.5 Gb/s remote carrier modulated upstream signal by employing a reflective SOA-EA monolithically integrated circuit...

Absorption process for removing krypton from the off-gas of an LMFBR fuel reprocessing plant

International Nuclear Information System (INIS)

Stephenson, M.J.; Dunthorn, D.I.; Reed, W.D.; Pashley, J.H.

1975-01-01

The Oak Ridge Gaseous Diffusion Plant selective absorption process for the collection and recovery of krypton and xenon is being further developed to demonstrate, on a pilot scale, a fluorocarbon-based process for removing krypton from the off-gas of an LMFBR fuel reprocessing plant. The new ORGDP selective absorption pilot plant consists of a primary absorption-stripping operation and all peripheral equipment required for feed gas preparation, process solvent recovery, process solvent purification, and krypton product purification. The new plant is designed to achieve krypton decontamination factors in excess of 10 3 with product concentration factors greater than 10 4 while processing a feed gas containing typical quantities of common reprocessing plant off-gas impurities, including oxygen, carbon dioxide, nitrogen oxides, water, xenon, iodine, and methyl iodide. Installation and shakedown of the facility were completed and some short-term tests were conducted early this year. The first operating campaign using a simulated reprocessing plant off-gas feed is now underway. The current program objective is to demonstrate continuous process operability and performance for extended periods of time while processing the simulated ''dirty'' feed. This year's activity will be devoted to routine off-gas processing with little or no deliberate system perturbations. Future work will involve the study of the system behavior under feed perturbations and various plant disturbances. (U.S.)

Krypton 81m and xenon 133 for complementary ventilation imaging in pulmonary perfusion studies: a clinical comparison. Chapter 12

International Nuclear Information System (INIS)

Weber, P.M.; Remedios, L.V.dos.

1978-01-01

Twenty-four patients with suspected pulmonary embolism were studied to determine the relative usefulness of 133 Xe and 81 Krsup(m) as indicators of pulmonary ventilation in complementing perfusion studies. In most cases, where krypton produced results superior to xenon, this could be attributed to better resolution of the 190 keV photon and to the fact that multiple views could be obtained, with each view paired precisely with a corresponding perfusion image, the direct result of the ease of use of krypton and its short 13 second half-life. This was well demonstrated in both of the patients with presumed pulmonary embolism and co-existing other pulmonary disease in which the results with xenon and krypton differed. In each case the mis-match was obscured by closely related areas of delayed xenon wash-out. In those patients where xenon demonstrated greater sensitivity in identifying areas of pulmonary disease, the lesions noted on wash-out appeared as areas of positive activity, while with krypton the defects were always photogenic and, when small probably obscured by scatter from adjacent normal activity. In the patient who might have been improperly categorized as a mis-match without the krypton study, the xenon study may have been normal because of inadequate equilibration time. (author)

Optimization of krypton yields for rp-process studies at ISOLDE (CERN)

CERN Document Server

Kankainen, Anu Kristiina; Fraile-Prieto, L M; Jokinen, A; Leitner, M S; Oinonen, M; Peräjärvi, K; Ravn, H L

2004-01-01

The production of neutron-deficient krypton isotopes having astrophysical importance has been studied at the ISOLDE PBS facility at CERN. To investigate several effects on the yield a Monte Carlo code has been extensively applied.

Electron excitation coefficients of neutral and ionic levels of krypton in Townsend discharges

International Nuclear Information System (INIS)

Malovic, G.N.; Strinic, A.I.; Petrovic, Z.Lj.; Sadeghi, N.

2006-01-01

In this paper, we present experimental results for excitation coefficients of krypton atoms to several Kr and Kr + excited levels for E/N (electric field to gas particle number density ratio usually in units of Townsend, 1 Td = 10 -21 V m 2 ) values from 7 x 10 -20 V m 2 to above 1 x 10 -17 V m 2 . The data have been obtained in two different parallel plate self-sustained Townsend discharge drift tubes. The spatial distribution of the emission intensities were recorded and then normalized to give excitation coefficients at the anode, by using the electron flux at this point. The values of these coefficients are placed on an absolute scale by using a standard tungsten ribbon lamp calibrated against a primary blackbody radiation standard. The ionization rates at different E/N are obtained from the spatial emission profiles. The data for atomic krypton levels 2p 2 , 2p 3 , 2p 5 , 2p 6 , 2p 7 , 2p 8 , 3p 5 and 3p 6 (in Paschen notation) were converted to excitation coefficients by using quenching coefficients from the literature. The emission coefficients of eight 4s 2 4p 4 ( 3 P)5p levels of Kr + have also been measured for E/N values from about 1 x 10 -18 V m 2 up to nearly 8 x 10 -18 V m 2

Excitation mechanisms in singly ionized krypton laser

International Nuclear Information System (INIS)

El-Sherbini, Th.M.

1982-01-01

Lifetimes for the low lying 4p 4 4d and 4p 4 5s levels of singly ionized krypton laser are calculated, taking into account configuration interaction effects. The results show that some of these levels are metastable. They also suggest a two step excitation from the ground state of the ion (or the atom) to the upper 4p 4 5p laser levels involving some intermediate metastable states as a possible excitation mechanism. (author)

On the cholesterol transfer rates in the rat. The search for a slow component (1961); Sur les vitesses de transfert du cholesterol chez le rat. Recherche d'une composante lente (1961)

Energy Technology Data Exchange (ETDEWEB)

Chevallier, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

The ingestion of cholesterol 4-{sup 14}C during 7, 27 and 43 weeks enables one to find that the size of the cholesterol transfer space in rats is not modified by the duration of the experiment. In male rats, the results obtained confirm on the one hand that 50 to 60 per cent of the total cholesterol of the animal is renewed by transfer, and on the other hand that 40 to 60 per cent of the cholesterol of the rat is inert as regards this process. In female rats, the size of the transfer space is 10 per cent larger than in the males, but the general conclusions are the same. (author) [French] L'ingestion de cholesterol 4-{sup 14}C durant 7, 27 et 43 semaines permet de constater que la grandeur de l'espace de transfert du cholesterol chez les rats n'est pas modifie par la duree de l'experience. Pour les rats males, les resultats, d'une part, confirment que 50 a 60 pour cent du cholesterol total de l'animal est renouvele par transfert, et d'autre part, que 40 a 50 pour cent du cholesterol du rat est inerte en regard de ce processus. Pour les rats femelles, la grandeur de l'espace de transfert est superieure de 10 pour cent a celle de l'espace de transfert des males, mais les conclusions d'ensemble restent les memes. (auteur)

Separation of nitrogen-krypton by the freeze-dried cellulose acetate membrane

International Nuclear Information System (INIS)

Tanioka, Akihiko; Ishikawa, Kinzo; Kakuta, Akio; Ozaki, Osamu; Oono, Masanori.

1977-01-01

The utility of freeze-dried cellulose acetate membranes, which consist of a thin skin layer supported upon a more porous matrix substructure, was examined for separation of nitrogen-radioactive krypton 85. The high permeable and separative membranes were prepared by fixed freezed-drying of swollen membrane after evaporation of acetone for 4-6 minutes. The permeation rate of nitrogen was 10 -1 -10 -3 (cc/cm 2 .sec.atm). Knudsen flow was predominant, since the permeation rate was inversely proportional to square root of molecular weight of gases. The influence of viscous flow was also observed by slight dependence on the pressure. The mean pore size was calculated by the equation of gas permeation in porous media. There exist fine pores of 30-40A radii in the skin layer. The separation factor (dilution of Kr) was about 0.7 and the separation efficiency was 60%. The collision between different gas molecules (Present-de Bethunes' effect) and the influence of viscous flow depreciates the efficiency. The separation efficiency which was determined by the experiment coincided with the one predicted according to the Present-de Bethunes' equation, supposing that the pore size in skin layer was 10-25A. (auth.)

Simultaneous detection of xenon and krypton in equine plasma by gas chromatography-tandem mass spectrometry for doping control.

Science.gov (United States)

Kwok, Wai Him; Choi, Timmy L S; So, Pui-Kin; Yao, Zhong-Ping; Wan, Terence S M

2017-02-01

Xenon can activate the hypoxia-inducible factors (HIFs). As such, it has been allegedly used in human sports for increasing erythropoiesis. Krypton, another noble gas with reported narcosis effect, can also be expected to be a potential and less expensive erythropoiesis stimulating agent. This has raised concern about the misuse of noble gases as doping agents in equine sports. The aim of the present study is to establish a method for the simultaneous detection of xenon and krypton in equine plasma for the purpose of doping control. Xenon- or krypton-fortified equine plasma samples were prepared according to reported protocols. The target noble gases were simultaneously detected by gas chromatography-triple quadrupole mass spectrometry using headspace injection. Three xenon isotopes at m/z 129, 131, and 132, and four krypton isotopes at m/z 82, 83, 84, and 86 were targeted in selected reaction monitoring mode (with the precursor ions and product ions at identical mass settings), allowing unambiguous identification of the target analytes. Limits of detection for xenon and krypton were about 19 pmol/mL and 98 pmol/mL, respectively. Precision for both analytes was less than 15%. The method has good specificity as background analyte signals were not observed in negative equine plasma samples (n = 73). Loss of analytes under different storage temperatures has also been evaluated. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

The dielectronic satellites to the 2s-3p Ne-like krypton resonance lines

International Nuclear Information System (INIS)

Khakhalin, S.Ya.; Dyakin, V.M.; Faenov, A.Ya.; Fiedorowicz, H.; Bartnik, A.; Parys, P.; Nilsen, J.; Osterheld, A.

1994-01-01

We present an analysis of dielectronic satellite spectra of 2p 6 -2s2p 6 3p Ne-like krypton resonance lines. The satellite structure was registered with high (better than λ/Δλ > 3500) spectral resolution in the emission of a laser irradiated gas puff target. We perform an unambiguous identification of satellite lines caused by radiative transitions from autoionizing states of sodium-like krypton ions. A total of about 20 spectral features are identified, most of them for the first time. Very good agreement between the satellite structure calculations and experimental emission spectra is obtained. (orig.)

The dielectronic satellites to the 2s-3p Ne-like krypton resonance lines

Energy Technology Data Exchange (ETDEWEB)

Khakhalin, S.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Dyakin, V.M. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Faenov, A.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Fiedorowicz, H. (Inst. of Optoelectronics, Warsaw (Poland)); Bartnik, A. (Inst. of Optoelectronics, Warsaw (Poland)); Parys, P. (Inst. of Plasma Physics and Laser Microfusion, Warsaw (Poland)); Nilsen, J. (Lawrence Livermore National Lab., Livermore, CA (United States)); Osterheld, A. (Lawrence Livermore National Lab., Livermore, CA (United States))

1994-08-01

We present an analysis of dielectronic satellite spectra of 2p[sup 6]-2s2p[sup 6]3p Ne-like krypton resonance lines. The satellite structure was registered with high (better than [lambda]/[Delta][lambda] > 3500) spectral resolution in the emission of a laser irradiated gas puff target. We perform an unambiguous identification of satellite lines caused by radiative transitions from autoionizing states of sodium-like krypton ions. A total of about 20 spectral features are identified, most of them for the first time. Very good agreement between the satellite structure calculations and experimental emission spectra is obtained. (orig.).

Radioactive Iodine and Krypton Control for Nuclear Fuel Reprocessing Facilities

Directory of Open Access Journals (Sweden)

Nick R. Soelberg

2013-01-01

Full Text Available The removal of volatile radionuclides generated during used nuclear fuel reprocessing in the US is almost certain to be necessary for the licensing of a reprocessing facility in the US. Various control technologies have been developed, tested, or used over the past 50 years for control of volatile radionuclide emissions from used fuel reprocessing plants. The US DOE has sponsored, since 2009, an Off-gas Sigma Team to perform research and development focused on the most pressing volatile radionuclide control and immobilization problems. In this paper, we focus on the control requirements and methodologies for 85Kr and 129I. Numerous candidate technologies have been studied and developed at laboratory and pilot-plant scales in an effort to meet the need for high iodine control efficiency and to advance alternatives to cryogenic separations for krypton control. Several of these show promising results. Iodine decontamination factors as high as 105, iodine loading capacities, and other adsorption parameters including adsorption rates have been demonstrated under some conditions for both silver zeolite (AgZ and Ag-functionalized aerogel. Sorbents, including an engineered form of AgZ and selected metal organic framework materials (MOFs, have been successfully demonstrated to capture Kr and Xe without the need for separations at cryogenic temperatures.

Electromagnetic calorimeter on liquid krypton

International Nuclear Information System (INIS)

Bazzotti, M.; Bianco, G.L.; Lanni, F.; Maggi, B.; Palombo, F.; Sala, A.

1990-01-01

This paper reports on use of noble condensed gases as calorimeter media that is attractive due to the possibility to get not only good energy resolution (like in NaI and CsI calorimeters) but better space resolution for photons. Longitudinal segmentation can provide information for particle identification by dE/dx and also e/π-separation based on longitudinal structure of the shower. The best material for this aim is of course liquid Zenon, but it is impossible to get the necessary amount of it in reasonable time. Therefore, the authors have stopped their choice on the next candidate-liquid Krypton (LKr). Its sufficient amount can be obtained before to the beginning of the experiment

Muonium localization in solid krypton

International Nuclear Information System (INIS)

Storchak, V.; Cox, S.F.J.; Brewer, J.H.; Morris, G.D.

1995-06-01

Muonium spin relaxation in zero, longitudinal and transverse magnetic fields has been studied in solid and liquid krypton in the temperature range from 2 K to 120 K. In the solid at low temperatures, the spin dynamics exhibit features characteristic of a magnetically dilute crystal, permitting measurements of exceptionally low muonium diffusion rates. At the lowest temperatures, a static Kubo-Toyabe relaxation function has been observed for the first time for the atomic muonium state, indicating strong interstitial localization in the Kr lattice at low temperatures; muonium is determined to be localized at the tetrahedral interstitial position. At high temperatures, muonium diffusion in solid Kr exhibits a non-classical behaviour. (author). 31 refs., 6 figs

Effective and accurate approach for modeling of commensurate-incommensurate transition in krypton monolayer on graphite.

Science.gov (United States)

Ustinov, E A

2014-10-07

Commensurate-incommensurate (C-IC) transition of krypton molecular layer on graphite received much attention in recent decades in theoretical and experimental researches. However, there still exists a possibility of generalization of the phenomenon from thermodynamic viewpoint on the basis of accurate molecular simulation. Recently, a new technique was developed for analysis of two-dimensional (2D) phase transitions in systems involving a crystalline phase, which is based on accounting for the effect of temperature and the chemical potential on the lattice constant of the 2D layer using the Gibbs-Duhem equation [E. A. Ustinov, J. Chem. Phys. 140, 074706 (2014)]. The technique has allowed for determination of phase diagrams of 2D argon layers on the uniform surface and in slit pores. This paper extends the developed methodology on systems accounting for the periodic modulation of the substrate potential. The main advantage of the developed approach is that it provides highly accurate evaluation of the chemical potential of crystalline layers, which allows reliable determination of temperature and other parameters of various 2D phase transitions. Applicability of the methodology is demonstrated on the krypton-graphite system. Analysis of phase diagram of the krypton molecular layer, thermodynamic functions of coexisting phases, and a method of prediction of adsorption isotherms is considered accounting for a compression of the graphite due to the krypton-carbon interaction. The temperature and heat of C-IC transition has been reliably determined for the gas-solid and solid-solid system.

Radiometric titration of officinal radiopharmaceuticals using radioactive kryptonates as end-point indicators. II. Citric, tartaric, undecylenic acids

Energy Technology Data Exchange (ETDEWEB)

Harangozo, M.; Jombik, J.; Schiller, P. (Komenskeho Univ., Bratislava (Czechoslovakia). Farmaceuticka Fakulta); Toelgyessy, J. (Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia). Chemickotechnologicka Fakulta)

1981-01-01

A method for the determination of citric, tartaric and undecylenic acids based on radiometric titration with 0.1 or 0.05 mole.l/sup -1/ NaOH was developed. As an indicator of the end point, radioactive kryptonate of glass was used. Experimental technique, results of determinations as well as other possible applications of the radioactive kryptonate of glass for end point determination in alkalimetric analyses of officinal pharmaceuticals are discussed.

Steady state operation of the first cryogenic column in a krypton separation system

International Nuclear Information System (INIS)

von Ammon, R.; Bumiller, W.; Hutter, E.; Neffe, G.

1981-01-01

Recent results obtained during the operation of the inactive test unit KRETA for the cryogenic separation of krypton from simulated reprocessing off-gases are presented. The first rectification column of this unit was modified by shortening its lower part from 18 to 8 practical plates and placing the feed point into the warmer, krypton-rich section. Two essential results were thus achieved: plugging by desubliming xenon was not observed even at xenon feed concentrations as high as 1 vol.-%; and, accumulation of oxygen was much lower than in the column version used previously, thus reducing the potential hazard by ozone formation drastically. The accumulation of methane, however, was found to be high, in agreement with calculations

Photocoagulation of disciform macular lesions with krypton laser.

Science.gov (United States)

Bird, A C; Grey, R H

1979-01-01

Ten vascular disciform mucular lesions were treated by krypton laser photocoagulation. In 8 the lesion resolved after therapy, and in 7 the retina remained flat for 6 months. On those patients treated successfully 6 had a visual acuity of 6/12 or better. The morphology of the laser lesion differed from that of the argon lesion in that there is no evidence of thermal coagulation of the inner retina near the foveola. Images PMID:574396

Selected radionuclides. Tritium, carbon-14, krypton-85, strontium-90, iodine, caesium 137, radon, plutonium

International Nuclear Information System (INIS)

1983-01-01

The release of radioactive materials to the environment potentially exposes populations to ionizing radiation and increases the risk of incurring deleterious health effects. The associations of released amounts to effects establish the health criteria for radionuclides. This report provides background information in establishing such health criteria for 14 C, 85 Kr, 90 Sr, 137 Cs, Radon, Plutonium, Iodine and Tritium, including environmental behaviour, sources, transport to man and dosimetry. A brief summary of the general aspects of radiation effects and of radiation protection considerations is presented

Development for a process for the adsorptive separation of krypton-85

International Nuclear Information System (INIS)

Messler, M.

1985-03-01

In the final process step of dissolver waste gas purification in a reprocessing facility, the radioactive noble gas Kr-85 is separated by physical separation processes. The experiments showed that the available mixture of air/Kr/Xe can be appropriately separated by chromatography. In principle, the adsorption column is laded with the waste gas and subsequently regenerated by puring with a carrier gas. A complete separation of the waste gas components can thus be achieved. He suggests itself as a purge gas. Fine-grained activated charcoals are to be preferred as adsorbing agents. Among the adsorptive process alternatives studied, one variant in which the adsorber was split into two halves and loaded at -130 0 C or -160 0 C proved to be particularly suitable. It can be seen that a total of only 0.2 m 3 of activated charcoal would be required for a commerical facility with a waste gas throughput of 100 nm 3 /h. The helium flux required only amounts to 4% of the waste gas flow to be purified. If valuable xenon is also to be recovered then this value increases to 7%. In this case the quantity of activated charcoal necessary would be 0.28 m 3 . A comparison with alternative process principles indicated that the adsorptive concept has advantages with respect to process engineering and regarding high safety standards in nuclear engineering facilities. (orig./HP) [de

Analysis of radioxenon and Krypton-85 at the BfS noble gas laboratory.

Science.gov (United States)

Schlosser, C; Bollhöfer, A; Schmid, S; Krais, R; Bieringer, J; Konrad, M

2017-08-01

Proportional counters and a β-γ coincidence system and their performance characteristics are described, with emphasis on internal and external quality controls. Typical limits of detection (LD) are 8mBqm -3 for 85 Kr and 4mBqm -3 for 133 Xe for the proportional counters, while for similar xenon volumes the LD for 133 Xe in the β-γ system is approximately 4 times lower. Results of comparative analyses agree above the limit of quantification. Xenon-133 levels in southern Germany are presently at or below the LD of the proportional counters, but above the LD of the β-γ system, which is now routinely used for analysis of environmental samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Les méthodesthermiques de production des hydrocarbures. Chapitre 1 : transfert de chaleur et de masse Thermal Methods of Hydrocarbon Production. Chapter 1 : Heat and Mass Transfer

Directory of Open Access Journals (Sweden)

Bia P.

2006-11-01

Full Text Available Après un rappel général sur le transfert de chaleur et de masse ainsi que sur les lois de conservation dans les milieux continus, on traite de l'adaptation de ces lois au cas des milieux poreux. On donne ensuite des informations quantitatives sur les grandeurs physiques mises en jeu par les phénomènes de transfert en milieu poreux. After making a general review of heat and mass transfer a well as of laws of conservation in continua, this chapter describes how these laws con be adopted to the case of porous media. Quantitative data are then given on the physical magnitudes brought into play by transfer phenomena in porous media.

Particle simulation of grid system for krypton ion thrusters

Directory of Open Access Journals (Sweden)

Maolin CHEN

2018-04-01

Full Text Available The transport processes of plasmas in grid systems of krypton (Kr ion thrusters at different acceleration voltages were simulated with a 3D-PIC model, and the result was compared with xenon (Xe ion thrusters. The variation of the screen grid transparency, the accelerator grid current ratio and the divergence loss were explored. It is found that the screen grid transparency increases with the acceleration voltage and decreases with the beam current, while the accelerator grid current ratio and divergence loss decrease first and then increase with the beam current. This result is the same with Xe ion thrusters. Simulation results also show that Kr ion thrusters have more advantages than Xe ion thrusters, such as higher screen grid transparency, smaller accelerator grid current ratio, larger cut-off current threshold, and better divergence loss characteristic. These advantages mean that Kr ion thrusters have the ability of operating in a wide range of current. Through comprehensive analyses, it can be concluded that using Kr as propellant is very suitable for a multi-mode ion thruster design. Keywords: Grid system, Ion thrusters, Krypton, Particle in cell method, Plasma

Christophe Couderc, dir., Le théâtre Espagnol du Siècle d'Or en France. De la traduction au transfert culturel

Directory of Open Access Journals (Sweden)

Christian Andrès

2012-12-01

Full Text Available Review of Christophe Couderc, Le théâtre Espagnol du Siècle d'Or en France. De la traduction au transfert culturel, Presses Universitaires de Paris Ouest, París, 2012, 299 pp. ISBN: 978-2-84016-102-8.

Pulmonary ventilation imaging and function studies with krypton-81m

International Nuclear Information System (INIS)

Kaplan, E.; Mayron, L.W.; Gergans, G.A.; Friedman, A.M.; Gindler, J.E.

1976-01-01

Chronic obstructive lung disease is a significant entity throughout the world. It is etiologically related to smoking, air pollution and mining. To arrest asymptomatic disease, early diagnosis is required, implying an efficacious, reliable and available methodology, which has the potential for screening suspect populations. Krypton-81m is a 13-second radionuclide that emits a 190 keV gamma ray; it may be produced from a rubidium-81-krypton-81m generator and delivery system, devised, produced and evaluated by the authors. The generator effluent, in gaseous form, may be continually inhaled by a subject while static equilibrium images and dynamic studies of ventilation are produced with a gamma scintillation camera system. The wash-in of /sup 81m/Kr produces heterogeneous images, the activity being proportional to regional ventilation due to rapid decay. Minimal ventilatory delays are detectable. Normal subjects and patients with obstructive lung disease have been evaluated by static equilibrium and dynamic studies. The sensitivity of /sup 81m/Kr studies is currently being compared with various other pulmonary function tests, to evaluate its potential as an appropriate screening technique

Completion of Kr-81 and Kr-85 Analysis Development for Hydrogeology and Testing its Validity by Assessing Aquifer Recharge Rates

International Nuclear Information System (INIS)

Thonnard, Norbert

2007-01-01

The overall objective was to complete the development of a RIMS-based analytical technique to determine the concentration of the rare krypton radioisotopes, 81Kr and 85Kr, in samples of interest to the geoscience and planetary science community The key to RIMS is the use of tunable lasers to selectively and efficiently excite by resonant photon absorption atomic states unique to the chosen element. Ionization of the specified element can then occur while excluding all other constituents of the sample, bringing detection limits down to the single-atom level. Combining RIMS with several steps of isotopic enrichment makes detection of a rare isotope, such as 81Kr, feasible. A complete process for groundwater samples consists of starting with (1) collecting the groundwater sample, (2) degassing the water sample, (3) separating Kr from the recovered gases, (4 and 5) two isotopic enrichments reducing interfering isotopes by >109, and (6) detecting the rare krypton isotope using RIMS in a time-of-flight system. Required water sample size is 20 liters for 81Kr and 10 to 3 liters for 85Kr. Weak links in the above steps were to be identified and rectified. Most of the troublesome issues were resolved, but unfortunately, two key difficulties could not be resolved with the available resources, so the overall, final goal of completing a suite of measurements was not achieved. In spite of this, valuable collaborations were established to demonstrate the value of 81Kr and 85Kr measurements in two critical applications, the future site of a nuclear waste repository, where high efficiency 81Kr measurements would allow groundwater dating of low-yield formations, and a multi-method analysis of potential contamination inflow into a large municipal water system, where the simplicity of interpretation of 85Kr measurements could become a valuable future interpretive tool. Therefore, samples were collected anyway, and processing started using the working parts of the method, so that

Resonance ionization spectroscopy of argon, krypton, and xenon using vacuum ultraviolet light

International Nuclear Information System (INIS)

Kramer, S.D.

1984-04-01

Resonant, single-photon excitation of ground state inert gases requires light in the vacuum ultraviolet spectral region. This paper discusses methods for generating this light. Efficient schemes for ionizing argon, krypton, and xenon using resonant, stepwise single-photon excitation are presented

Kratom alkaloids and O-desmethyltramadol in urine of a "Krypton" herbal mixture consumer.

Science.gov (United States)

Arndt, Torsten; Claussen, Ulrich; Güssregen, Brunhilde; Schröfel, Stefanie; Stürzer, Birgit; Werle, Annika; Wolf, Gerald

2011-05-20

A drug and alcohol withdrawal rehabilitation centre requested an analysis for "Krypton" in urine of a former opiate-addictive woman. She showed an altered clinical picture and behaviour with miosis, itchiness, agitation, and moderate euphoria after 3 months of until than successful treatment. Literature search revealed that "Krypton" is said to contain "Kratom" (leaves of Mitragyna speciosa), but could also contain O-desmethyltramadol (European Monitoring Centre for Drugs and Drug Addiction thematic paper "Spice"). Immunological drug screenings were done with test strips (nal von minden, Regensburg, Germany) and with cloned enzyme donor immunoassay (Microgenics, Passau, Germany). "Kratom" alkaloids and tramadol (metabolites) were analyzed by LC-MS/MS (ThermoFisher Scientific Quantum Ultra Triple Quadrupole mass spectrometer). Immunoassays were negative for amphetamines, barbiturates, benzodiazepines, benzoylecgonine, buprenorphine, ethylglucuronide, methadone (metabolite), opiates, oxycodone, and THC-COOH, and test strips were negative for tramadol and its metabolites (cut-off 10 mg/L for O-desmethyltramadol). LC-MS/MS detected the "Kratom" alkaloids mitragynine, speciociliatine, speciogynine, mitraciliatine, and paynantheine and approximately 9mg/L O-desmethyltramadol, but no tramadol and N-desmethyltramadol. The detection of M. speciosa alkaloids is a proof of "Kratom" abuse. Confronted with the analysis data, the patient admitted to have consumed 3-4 infusions of "Krypton". The origin of the O-desmethyltramadol is unclear. Tramadol abuse is unlikely since tramadol and N-desmethyltramadol (physiologically occurring in urine after tramadol intake) were not detectable. Consumption of a "Krypton" product spiked with O-desmethyltramadol could explain our findings and the patient's clinical picture. This would be in agreement with a most recent report about spiking apparently natural herbal mixtures with the synthetic opioid O-desmethyltramadol. Analysis of "Kratom

Electron drift velocity measurements in liquid krypton-methane mixtures

CERN Document Server

Folegani, M; Magri, M; Piemontese, L

1999-01-01

Electron drift velocities have been measured in liquid krypton, pure and mixed with methane at different concentrations (1-10% in volume) versus electric field strength, and a possible effect of methane on electron lifetime has been investigated. While no effect on lifetime could be detected, since lifetimes were in all cases longer than what measurable, a very large increase in drift velocity (up to a factor 6) has been measured.

Krypton ventilation imaging using dual-energy CT in chronic obstructive pulmonary disease patients: initial experience.

Science.gov (United States)

Hachulla, Anne-Lise; Pontana, François; Wemeau-Stervinou, Lidwine; Khung, Suonita; Faivre, Jean-Baptiste; Wallaert, Benoit; Cazaubon, Jean-François; Duhamel, Alain; Perez, Thierry; Devos, Patrick; Remy, Jacques; Remy-Jardin, Martine

2012-04-01

To evaluate the tolerance and level of enhancement achievable after inhalation of stable krypton. This study was approved by the institutional review board and the local ethics committee. Written informed consent was obtained from all subjects. The study was planned as a Fleming two-stage design, enabling one to assess the effectiveness of a newer treatment or technique on a small number of patients. At the end of each stage, the results are computed, and the trial can be stopped if the effectiveness is less than a minimum success rate or greater than an expected success rate. After informed consent was obtained, a total of 32 patients (ie, two successive series of 16 patients each) with severe emphysema underwent a dual-source, dual-energy chest computed tomographic (CT) examination after inhalation of a mixture of stable krypton (80%) and oxygen (20%), with reconstruction of diagnostic and ventilation images. For each patient, two regions of interest were selected on a diagnostic image, one in a region of severe emphysema (presumed to be poorly ventilated or not ventilated) and a second one in a region devoid of structural abnormalities (presumed to be normally ventilated), with measurements of attenuation values on the corresponding ventilation image. All examinations were successfully performed, without adverse effects. Differences in attenuation between normal lung and emphysematous areas were found in 28 patients (88%; 95% confidence interval: 71%, 96.5%). The maximal level of attenuation within normal lung was 18.5 HU. Krypton attenuation difference between normal and emphysematous lung was significant, with a median value of 51.8% (P krypton and its excellent clinical tolerance makes this gas eligible for ventilation CT examinations. © RSNA, 2012.

Liquid Krypton Calorimeter Calibration Software

CERN Document Server

Hughes, Christina Lindsay

2013-01-01

Calibration of the liquid krypton calorimeter (LKr) of the NA62 experiment is managed by a set of standalone programs, or an online calibration driver. These programs are similar to those used by NA48, but have been updated to utilize classes and translated to C++ while maintaining a common functionality. A set of classes developed to handle communication with hardware was used to develop the three standalone programs as well as the main driver program for online calibration between bursts. The main calibration driver has been designed to respond to run control commands and receive burst data, both transmitted via DIM. In order to facilitate the process of reading in calibration parameters, a serializable class has been introduced, allowing the replacement of standard text files with XML configuration files.

In situ measurements of krypton in xenon gas with a quadrupole mass spectrometer following a cold-trap at a temporarily reduced pumping speed

International Nuclear Information System (INIS)

Brown, E; Rosendahl, S; Huhmann, C; Weinheimer, C; Kettling, H

2013-01-01

A new method for measuring trace amounts of krypton in xenon using a cold trap with a residual gas analyzer has been developed, which achieves an increased sensitivity by temporarily reducing the pumping speed while expending a minimal amount of xenon. By partially closing a custom built butterfly valve between the measurement chamber and the turbomolecular pump, a sensitivity of 40 ppt has been reached. This method has been tested on an ultra-pure gas sample from Air Liquide with an unknown intrinsic krypton concentration, yielding a krypton concentration of 330±200 ppt.

‘Choses Virtuelles. Les Objects Matériels Perdus Ou Trouvés Dans Les Études De Transfert Culturel’

NARCIS (Netherlands)

Broomans, Pieternella; Andringa, Kim; Harry, Frédérique; Mareuge, Agathe; Terrisse, Bénédicte

2015-01-01

Petra Broomans s’attache à deux figures de médiateurs culturels, Constant Jacob Hansen et Philippine Wijsman, pour mettre en lumière le rôle joué par la perte ou la découverte de matériel – concret ou virtuel – dans les études de transfert culturel. L’attention portée au matériel permet de les

Theory of attosecond absorption spectroscopy in krypton

DEFF Research Database (Denmark)

Baggesen, Jan Conrad; Lindroth, Eva; Madsen, Lars Bojer

2012-01-01

A theory for time-domain attosecond pump–attosecond probe photoabsorption spectroscopy is formulated and related to the atomic response. The theory is illustrated through a study of attosecond absorption spectroscopy in krypton. The atomic parameters entering the formulation such as energies...... of the hole in this manner. In a second example, a hole is created in an inner shell by the first pulse, and the second probe pulse couples an even more tightly bound state to that hole. The hole decays in this example by Auger electron emission, and the absorption spectroscopy follows the decay of the hole...

All-Optical Atom Trap Trace Analysis: Potential Use of 85Kr in Safeguards Activities

International Nuclear Information System (INIS)

Kohler, M.; Sahling, P.; Sieveke, C.; Kirchner, G.

2015-01-01

Sensitive measurement techniques for the detection of anthropogenic tracers demand measurement resolutions down to single atoms, as it has been demonstrated by the first atom trap trace analysis experiments. However, technical limitations had lowered the sample throughput to about 200 per year per machine. We have developed an all-optical apparatus which allows higher sample throughput and small sample sizes at the same time. Krypton-85 as anthropogenic isotope is an ideal tracer for nuclear activities since the only relevant source term is fission. An increased 85Kr concentration in an air sample indicates, that a plume was passing by during sampling. In practice, however, its applicability may be limited by the global and regional background concentrations caused by the emissions of nuclear fuel reprocessing plants. The potential of 85Kr monitoring for safeguards applications has been discussed extensively. Among these is the short range detection of elevated concentrations of 85Kr in the vicinity of reprocessing plants. Our ATTA technique needs sample sizes of about 1 l of air only and thus for the first time will allow simple environmental sampling of 85Kr with high spatial and temporal resolution. The design of such a study including local sampling and tracer transport modelling in proximity to a reprocessing plants is outlined. In addition, such a study could be used also for validating near-field atmospheric dispersion models if the 85Kr source term is known. The potential of environmental analyzes of 85Kr during an IAEA short-notice access is discussed. It is shown that it crucially depends on the emission dynamics after shut-down of fuel dissolution which needs further study. (author)

An experimental study of the trapping and release of krypton in nickel

International Nuclear Information System (INIS)

Donnelly, S.E.; Ingram, D.C.; Armour, D.G.

1979-01-01

An experimental study is reported of the trapping and release of krypton implanted into nickel at low energies ( + incident on Ni (110) the maximum quantity of gas retained in the target was found to be approximately 2.5 x 10 15 ions cm -2 . (author)

Theoretical investigation of the secondary ionization in krypton and xenon

International Nuclear Information System (INIS)

Saffo, M.E.

1986-01-01

A theoretical investigation of the secondary ionization processes that responsible for the pre-breakdown ionization current growth in a uniform electric field was studied in krypton and xenon gases, especially at low values of E/P 0 which is corresponding to high values of pressure, since there are a number of possible secondary ionization processes. It is interesting to carry out a quantitative analysis for the generalized secondary ionization coefficient obtained previously by many workers in terms of the production of excited states and their diffusion to the cathode and their destruction rate in the gas body. From energy balance equation for the electrons in the discharge, the fractional percentage energy losses of ionization, excitation, and elastic collisions to the total energy gained by the electron from the field has been calculated for krypton and xenon, as a result of such calculations; the conclusion drawn is that at low values of E/P 0 the main energy loss of electrons are in excited collision. Therefore, we are adopting a theoretical calculation for W/α under the assumption that the photo-electron emission at the cathode is the predominated secondary ionization process. 14 tabs.; 12 figs.; 64 refs

Determination of distribution ratio for 60Co, 85Sr and 134Cs in loess medium

International Nuclear Information System (INIS)

Tanaka, Tadao; Ogawa, Hiromichi; Zhentang Li; Hui Wang; Kamiyama, Hideo.

1994-06-01

Distribution ratio R for 60 Co, 85 Sr and 134 Cs between loess and ground water was measured by using 16 loess samples taken from the field test site of China Institute for Radiation Protection, in which the field test of radionuclide migration had been performed. The R of each radionuclide was taken nearly constant value among 16 samples. This revealed that the site can be regarded as uniform loess medium from the view point of sorption ability. The sorption ability between the three radionuclides was the order of 134 Cs > 60 Co >> 85 Sr. The 85 Sr was an available nuclide for examining the migration phenomena, because 85 Sr might easily migrate in the loess medium due to its low sorption ability. The results of parametric check suggested that it is necessary to select the valid temperature and pH for determining the R value. The sorption of Sr on the loess was dominated by reversible ion-exchange reaction, while that of Co and Cs was dominated by irreversible one. (author)

AA stacking, tribological and electronic properties of double-layer graphene with krypton spacer.

Science.gov (United States)

Popov, Andrey M; Lebedeva, Irina V; Knizhnik, Andrey A; Lozovik, Yurii E; Potapkin, Boris V; Poklonski, Nikolai A; Siahlo, Andrei I; Vyrko, Sergey A

2013-10-21

Structural, energetic, and tribological characteristics of double-layer graphene with commensurate and incommensurate krypton spacers of nearly monolayer coverage are studied within the van der Waals-corrected density functional theory. It is shown that when the spacer is in the commensurate phase, the graphene layers have the AA stacking. For this phase, the barriers to relative in-plane translational and rotational motion and the shear mode frequency of the graphene layers are calculated. For the incommensurate phase, both of the barriers are found to be negligibly small. A considerable change of tunneling conductance between the graphene layers separated by the commensurate krypton spacer at their relative subangstrom displacement is revealed by the use of the Bardeen method. The possibility of nanoelectromechanical systems based on the studied tribological and electronic properties of the considered heterostructures is discussed.

Photochemistry of the ozone-water complex in cryogenic neon, argon, and krypton matrixes.

Science.gov (United States)

Tsuge, Masashi; Tsuji, Kazuhide; Kawai, Akio; Shibuya, Kazuhiko

2013-12-12

The photochemistry of ozone-water complexes and the wavelength dependence of the reactions were studied by matrix isolation FTIR spectrometry in neon, argon, and krypton matrixes. Hydrogen peroxide was formed upon the irradiation of UV light below 355 nm. Quantitative analyses of the reactant and product were performed to evaluate the matrix cage effect of the photoreaction. In argon and krypton matrixes, a bimolecular O((1)D) + H2O → H2O2 reaction was found to occur to form hydrogen peroxide, where the O((1)D) atom generated by the photolysis of ozone diffused in the cryogenic solids to encounter water. In a neon matrix, hydrogen peroxide was generated through intracage photoreaction of the ozone-water complex, indicating that a neon matrix medium is most appropriate to study the photochemistry of the ozone-water complex.

Electron correlation effects in the (e,2e) valence separation energy spectra of krypton

International Nuclear Information System (INIS)

Fuss, I.; Glass, R.; McCarthy, I.E.; Minchinton, A.; Weigold, E.

1981-04-01

Separation energy spectra and momentum distributions for the valence orbitals of krypton have been obtained at a total electron energy of 1200eV using (e,2e) spectroscopy with symmetric kinematics. The spectroscopic strength of the 4s orbital is found to be significantly split among ion states ranging into the continuum, whereas the spectroscopic strength of the 4p ground state transition is found to be essentially unity. The momentum distributions for the 4p -1 and 4s -1 transitions are well described by the corresponding Hartree-Fock ground state orbital momentum distributions. A number of configuration interaction calculations using predominantly the 4s4p 6 and 4s 2 4p 4 4d ( 2 Ssub(1/2)) configurations, have been carried out for the main 4s - 1 ion eigenstates. The results, although confirming severe splitting of the 4s -1 spectroscopic strength, over-estimate the 4s4p 6 component of the lowest 2 S level in the ion. The data provides a sensitive test of the variational determination of the parameters of pseudostates representing configurations not treated explicitly

[Krypton laser photocoagulation at low power setting for age-related macular degeneration complicated with subfoveal choroidal neovascularization].

Science.gov (United States)

Zhang, Cheng-fen; Jia, Yan; Li, Zhi-qing; Du, Hong; Han, Bao-ling

2004-12-01

To evaluate the efficacy of krypton laser photocoagulation for treatment of age-related macular degeneration (AMD) complicated with mainly subfoveal classic choroidal neovascularization (CNV). Seventeen eyes of 17 cases, aged 50 - 74 years (averaged 60.8 years) with mainly subfoveal classic choroidal neovascularization were treated with krypton laser at lower power setting. The treatment was completed in one session. Another course of treatment was given 4 weeks later if there was active leakage demonstrated at the CNV area. Visual acuity, anterior segment and fundus examination, perimetry test, fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were performed before and after treatment. The follow-up period was 3.5 years on average (1 - 8 years). There was no immediately decrease of visual acuity after treatment. All treated eyes showed absorption of hemorrhages and/or exudates and diminished leakages. Visual acuity was stable in 8 eyes; improved in 6 eyes (>/= 2 lines), and decreased in 3 eyes (Krypton laser photocoagulation at low power setting is an effective treatment for AMD with mainly classic subfoveal choroidal neovascularization.

Monitoring of kratom or Krypton intake in urine using GC-MS in clinical and forensic toxicology.

Science.gov (United States)

Philipp, Anika A; Meyer, Markus R; Wissenbach, Dirk K; Weber, Armin A; Zoerntlein, Siegfried W; Zweipfenning, Peter G M; Maurer, Hans H

2011-04-01

The Thai medicinal plant Mitragyna speciosa (kratom) is misused as a herbal drug. Besides this, a new herbal blend has appeared on the drugs of abuse market, named Krypton, a mixture of O-demethyltramadol (ODT) and kratom. Therefore, urine drug screenings should include ODT and focus on the metabolites of the kratom alkaloids mitragynine (MG), paynantheine (PAY), speciogynine (SG), and speciociliatine (SC). The aim of this study was to develop a full-scan gas chromatography-mass spectrometry procedure for monitoring kratom or Krypton intake in urine after enzymatic cleavage of conjugates, solid-phase extraction, and trimethylsilylation. With use of reconstructed mass chromatography with the ions m/z 271, 286, 329, 344, 470, 526, 528, and 586, the presence of MG, 16-carboxy-MG, 9-O-demethyl-MG, and/or 9-O-demethyl-16-carboxy-MG could be indicated, and in case of Krypton, with m/z 58, 84, 116, 142, 303, 361, 393, and 451, the additional presence of ODT and its nor metabolite could be indicated. Compounds were identified by comparison with their respective reference spectra. Depending on the plant type, dose, administration route, and/or sampling time, further metabolites of MG, PAY, SG, and SC could be detected. The limits of detection (signal-to-noise ratio of 3) were 100 ng/ml for the parent alkaloids and 50 ng/ml for ODT. As mainly metabolites of the kratom alkaloids were detected in urine, the detectability of kratom was tested successfully using rat urine after administration of a common user's dose of MG. As the metabolism in humans was similar, this procedure should be suitable to prove an intake of kratom or Krypton.

Cooling process in separation devices of krypton gas

Energy Technology Data Exchange (ETDEWEB)

Kimura, S; Sugimoto, K

1975-06-11

To prevent entry of impurities into purified gases and to detect leaks of heat exchanger in a separation and recovering device of krypton gas by means of liquefaction and distillation, an intermediate refrigerant having the same or slightly higher boiling point than that of gas to be cooled is used between the gas to be cooled (process gas) and refrigerant (nitrogen), and the pressure of the gas to be cooled is controlled to have a pressure higher than the intermediate refrigerant to cool the gas to be cooled.

Self-compression of femtosecond deep-ultraviolet pulses by filamentation in krypton.

Science.gov (United States)

Adachi, Shunsuke; Suzuki, Toshinori

2017-05-15

We demonstrate self-compression of deep-ultraviolet (DUV) pulses by filamentation in krypton. In contrast to self-compression in the near-infrared, that in the DUV is associated with a red-shifted sub-pulse appearing in the pulse temporal profile. The achieved pulse width of 15 fs is the shortest among demonstrated sub-mJ deep-ultraviolet pulses.

Development of a krypton-doped gas symmetry capsule platform for x-ray spectroscopy of implosion cores on the NIF

Energy Technology Data Exchange (ETDEWEB)

Ma, T., E-mail: ma8@llnl.gov; Chen, H.; Patel, P. K.; Schneider, M. B.; Barrios, M. A.; Casey, D. T.; Hammel, B. A.; Berzak Hopkins, L. F.; Jarrott, L. C.; Khan, S. F.; Nora, R.; Pak, A.; Scott, H. A.; Spears, B. K.; Weber, C. R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Chung, H.-K. [International Atomic Energy Agency, Vienna (Austria); Lahmann, B.; Sio, H. [Plasma Fusion and Science Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Rosenberg, M. J.; Regan, S. P. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

2016-11-15

The electron temperature at stagnation of an ICF implosion can be measured from the emission spectrum of high-energy x-rays that pass through the cold material surrounding the hot stagnating core. Here we describe a platform developed on the National Ignition Facility where trace levels of a mid-Z dopant (krypton) are added to the fuel gas of a symcap (symmetry surrogate) implosion to allow for the use of x-ray spectroscopy of the krypton line emission.

Development of a krypton-doped gas symmetry capsule platform for x-ray spectroscopy of implosion cores on the NIF.

Science.gov (United States)

Ma, T; Chen, H; Patel, P K; Schneider, M B; Barrios, M A; Casey, D T; Chung, H-K; Hammel, B A; Berzak Hopkins, L F; Jarrott, L C; Khan, S F; Lahmann, B; Nora, R; Rosenberg, M J; Pak, A; Regan, S P; Scott, H A; Sio, H; Spears, B K; Weber, C R

2016-11-01

The electron temperature at stagnation of an ICF implosion can be measured from the emission spectrum of high-energy x-rays that pass through the cold material surrounding the hot stagnating core. Here we describe a platform developed on the National Ignition Facility where trace levels of a mid-Z dopant (krypton) are added to the fuel gas of a symcap (symmetry surrogate) implosion to allow for the use of x-ray spectroscopy of the krypton line emission.

Calculation of partial enthalpies in argon-krypton mixtures by NPT molecular dynamics

NARCIS (Netherlands)

Sindzingre, P.; Massobrio, C.; Ciccotti, G.; Frenkel, D.

1989-01-01

In an earlier paper, we have indicated how, by using a particle-insertion technique, partial molar enthalpies and related quantities can be evaluated from simulations on a single state point. In the present paper we apply this method to a Lennard-Jones argon-krypton mixture. For this particular

Disposal of Kr-85 separated from the dissolver off-gas of a reprocessing plant for LWR fuels

International Nuclear Information System (INIS)

Nommensen, O.

1981-08-01

The principle of the radiation protection to keep the radiation load of the population as low as possible requires the development of methods for retaining the radionuclide Krypton 85 seperated off the dissolver waste gas of future reprocessing plants for LWR-nuclear fuel elements. In a recommendation of the RSK the long-termed storage of the Kr-85 in a pressure gas bottle and the marine disposal we considered to be disposal methods low in risk. The present work develops a concept for both of the disposal methods and demonstrates their technical feasibility. The comparison of the cost estimations effected for both of the disposal methods shows that the costs related with the marine disposal of the pressure gas bottles amounting to 1.90 DM/kg of reprocessed U fall by the factor 10 below the costs that result from the surface storage of the bottles. In both cases was referred to a reprocessing capacity of 1400 t U/a corresponding to 50 GW installed nuclear power, thereby accumulating approximately 629 PBq (17 MCi) Kr-85 per year. Both concepts project the seperated radioactive inert gas to be filled in pressure gas bottles in a low temperature rectification plant. Each of the 85 bottles to be filled per year contains 7.4 PBq (200 kCi) Kr-85. (orig./HP) [de

Performance of an electromagnetic liquid krypton calorimeter based on a ribbon electrode tower structure

Science.gov (United States)

Barr, G. D.; Bruschini, C.; Bocquet, C.; Buchholz, P.; Cundy, D.; Doble, N.; Funk, W.; Gatignon, L.; Gonidec, A.; Hallgren, B.; Kesseler, G.; Lacourt, A.; Laverrière, G.; Linser, G.; Martini, M.; Norton, A.; Schinzel, D.; Seidl, W.; Sozzi, M. S.; Taureg, H.; Vossnack, O.; Wahl, H.; Wertelaers, P.; Weterings, J.; Ziolkowski, M.; Kalinin, A.; Kekelidze, V.; Kozhevnikov, Yu.; Bertolotto, L.; Carassiti, V.; Duclos, J.; Gianoli, A.; Frabetti, P. L.; Savriè, M.; Zeitnitz, O.; Calvetti, M.; Lubrano, P.; Pepe, M.; Calafiura, P.; Cerri, C.; Costantini, F.; Fantechi, R.; Gorini, B.; Mannelli, I.; Marzulli, V.; Bédérède, D.; Debu, P.; Givernaud, A.; Gosset, L.; Heitzmann, J.; Mazzucato, E.; Peyaud, B.; Turlay, R.; Biino, C.; Ceccucci, A.; Maas, P.; Palestini, S.; Cagliari-Cambridge-CERN-Dubna-Edinburgh-Ferrara-Mainz-Orsay-Perugia-Pisa-Saclay-Siegen-Torino-Vienna Collaboration

1996-02-01

The NA48 collaboration is preparing a new experiment at CERN aiming to study CP violation in the K 0- overlineK 0 system with an accuracy of 2 × 10 -4 in the parameter Re(ɛ'/ɛ). Decays in two π0's will be recorded by a quasi-homogeneous liquid krypton calorimeter. A liquid krypton calorimeter has been chosen to combine good energy, position and time resolution with precise charge calibration and long-term stability. The prototype calorimeter incorporating the final design of the electrode read-out structure is presented in this paper. An energy resolution of {≃3.5%}/{√E} with a constant term smaller than 0.5% has been obtained. The time resolution was found to be better than 300 ps above 15 GeV.

Krypton laser photocoagulation induces retinal vascular remodeling rather than choroidal neovascularization.

Science.gov (United States)

Behar-Cohen, F; Benezra, D; Soubrane, G; Jonet, L; Jeanny, J C

2006-08-01

The purpose of this study is to analyze the retina and choroid response following krypton laser photocoagulation. Ninety-two C57BL6/Sev129 and 32 C57BL/6J, 5-6-week-old mice received one single krypton (630 nm) laser lesion: 50 microm, 0.05 s, 400 mW. On the following day, every day thereafter for 1 week and every 2-3 days for the following 3 weeks, serial sections throughout the lesion were systematically collected and studied. Immunohistology using specific markers or antibodies for glial fibrillary acidic protein (GFAP) (astrocytes, glia and Muller's cells), von Willebrand (vW) (vascular endothelial cells), TUNEL (cells undergoing caspase dependent apoptosis), PCNA (proliferating cell nuclear antigen) p36, CD4 and F4/80 (infiltrating inflammatory and T cells), DAPI (cell nuclei) and routine histology were carried out. Laser confocal microscopy was also performed on flat mounts. Temporal and spatial observations of the created photocoagulation lesions demonstrate that, after a few hours, activated glial cells within the retinal path of the laser beam express GFAP. After 48 h, GFAP-positive staining was also detected within the choroid lesion center. "Movement" of this GFAP-positive expression towards the lasered choroid was preceded by a well-demarcated and localized apoptosis of the retina outer nuclear layer cells within the laser beam path. Later, death of retinal outer nuclear cells and layer thinning at this site was followed by evagination of the inner nuclear retinal layer. Funneling of the entire inner nuclear and the thinned outer nuclear layers into the choroid lesion center was accompanied by "dragging" of the retinal capillaries. Thus, from days 10 to 14 after krypton laser photocoagulation onward, well-formed blood capillaries (of retinal origin) were observed within the lesion. Only a few of the vW-positive capillary endothelial cells stained also for PCNA p36. In the choroid, dilatation of the vascular bed occurred at the vicinity of the

Layered packaging: A synergistic method of transporting radioactive material

International Nuclear Information System (INIS)

Hohmann, G.L.

1989-01-01

The DOE certification for a transportation cask used to ship radioactive Krypton 85 from the Idaho Chemical Processing Plant (ICPP) to Oak Ridge National Laboratory (ORNL), was allowed to expire in 1987. The Westinghouse Idaho Nuclear Company (WINCO) was charged by DOE with modifying this cask to meet all current NRC requirements and preparing an updated Safety Analysis Report for Packaging, which would be submitted by DOE to the NRC for certification. However, an urgent need arose for ORNL to receive Krypton 85 which was in storage at the ICPP, which would not allow time to obtain certification of the modified shipping cask. WINCO elected to use a layered shipping configuration in which the gaseous Krypton 85 was placed in the uncertified, modified shipping cask to make use of its shielding and thermal insulation properties. This cask was then inserted into the Model No. 6400 (Super Tiger) packaging using a specially constructed plywood box and polyurethane foam dunnage. Structural evaluations were completed to assure the Super Tiger would provide the necessary impact, puncture, and thermal protection during maximum credible accidents. Analyses were also completed to determine the uncertified Krypton shipping cask would provide the necessary containment and shielding for up to 3.7 E+14 Bq of Krypton 85 when packaged inside the Super Tiger. The resulting reports, based upon this layered packaging concept, were adequate to first obtain DOE certification for several restricted shipments of Krypton 85 and then NRC certification for unrestricted shipments

Supershort avalanche electron beam in SF6 and krypton

Science.gov (United States)

Zhang, Cheng; Tarasenko, Victor F.; Gu, Jianwei; Baksht, Evgeni Kh.; Beloplotov, Dmitry V.; Burachenko, Alexander G.; Yan, Ping; Lomaev, Mikhail I.; Shao, Tao

2016-03-01

Runaway electrons play an important role in the avalanche formation in nanosecond- and subnanosecond- pulse discharges. In this paper, characteristics of a supershort avalanche electron beam (SAEB) generated at the subnanosecond and nanosecond breakdown in sulfur hexafluoride (SF6 ) in an inhomogeneous electric field were studied. One pulser operated at negative polarity with voltage pulse amplitude of ˜130 kV and rise time of 0.3 ns. The other pulser operated at negative polarity with voltage pulse amplitude of 70 kV and rise time of ˜1.6 ns . SAEB parameters in SF6 are compared with those obtained in krypton (Kr), nitrogen (N2 ), air, and mixtures of SF6 with krypton or nitrogen. Experimental results showed that SAEB currents appeared during the rise-time of the voltage pulse for both pulsers. Moreover, amplitudes of the SAEB current in SF6 and Kr approximately ranged from several to tens of milliamps at atmospheric pressure, which were smaller than those in N2 and air (ranging from hundreds of milliamps to several amperes). Furthermore, the concentration of SF6 additive could significantly reduce the SAEB current in N2-SF6 mixture, but it slightly affected the SAEB current in Kr -SF6 mixture because of the atomic/molecular ionization cross section of the gas had a much greater impact on the SAEB current rather than the electronegativity.

CERN: From Russia with krypton

International Nuclear Information System (INIS)

Anon.

1995-01-01

Full text: Arecent arrival at CERN is a cryostat built under the auspices of thelnternational Science and Technology Center (ISTC), a programme funded by the European Union, Japan, Russia, and the US which aims to promote the integration of former Soviet Union scientists and industry into global research and development activities. The new cryostat, built by Moscowbased Krunichev Enterprises, better known for its involvement in the ''Proton'' space rocket and the ''Mir'' space station, will form a vital part of the NA48 experiment at the SPS synchrotron. NA48, a Cagliari/Cambridge/CERN/ Dubna/Edinburgh/Ferrara/Mainz/Orsay/Perugia/Pisa/Saclay/Siegen/ Turin/Vienna collaboration, aims to study the small asymmetry in the properties of matter and antimatter known as CP violation, and should be fully ready to collect data next year. Through its links with Dubna's Joint Institute of Nuclear Research (JINR), near Moscow, NA48 has launched a number of initiatives designed to involve Russian physicists and industry in the experiment. The bargain 22 tonnes of krypton for NA48's energy-measuring calorimeter were manufactured at a specially- built factory in Russia. INTAS, the European Union-backed scheme for the promotion of cooperation with former Soviet Union scientists, provides funds for Dubna physicists to visit Western Europe. INTAS will also provide computing and networking infrastructure allowing the Russian physicists to participate fully in NA48's programme. As well as the cryostat, NA48's collaborating institutes have placed other orders with Russian suppliers. INFN Pisa has ordered 14,000 electrical feed-though contacts from the Budker Institute in Novosibirsk, whilst Saclay has placed contracts elsewhere for vacuum and other equipment. The new cryostat forms part of a joint project of INFN Pisa and CERN, involving scientists from Dubna, Edinburgh, and Saclay. The Russian part was built by Krunichev

Production and recombination of radiation defects in argon and krypton crystals

International Nuclear Information System (INIS)

Giersberg, E.J.

1981-01-01

Relative changes in the lattice constants of argon and krypton crystals have been measured by X-ray diffraction. As a result X-ray irradiation is found to produce stable defects. The recombination behaviour of these defects can be determined by isochronous and isothermal annealing. The creation of primary defects can be explained by exciton excitation and double-ionisation. (orig.) [de

The K Auger spectrum of krypton from the 83Rb decay

International Nuclear Information System (INIS)

Kovalik, A.; Gorozhankin, V.M.; Novgorodov, A.F.

1990-01-01

The K Auger spectrum of krypton was analyzed at the instrumental resolution of 6.5 eV using the evaporated 83 Rb source. The energies and relative intensities of the KLL-, KLX-, and KMX- Auger transitions were determined as well as the natural energy widths some of them. The results were compared with the theoretical predictions. 31 refs.; 3 figs.; 6 tabs

Krypton Gas for High Quality Single Wall Carbon Nanotubes Synthesis by KrF Excimer Laser Ablation

Directory of Open Access Journals (Sweden)

Jasim Al-Zanganawee

2015-01-01

Full Text Available We report for the first time the production of single wall carbon nanotubes (SWCNTs by KrF excimer laser ablation method under the krypton gas atmosphere. For the ablation experiment 450 mJ energy and 30 Hz repetition rate KrF excimer laser was used, and the target was prepared with the following composition: 0.6% Ni, 0.6% Co, and 98.8% C (atomic percentage. The ablation product was characterized by confocal Raman microspectroscopy, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and thermogravimetric analysis (TGA. The SWCNTs obtained are a mixture of semiconducting and metallic types with narrow diameters distribution of 1.26 to 1.49 nm, are micrometers long, and contain low amount of graphite and amorphous carbon.

ATTA-3: a State-of-the-Art Instrument for Radio-Krypton Dating

Science.gov (United States)

Jiang, W.; Zappala, J. C.; Bailey, K.; Lu, Z.; Müller, P.; O'Connor, T. P.

2013-12-01

The ATTA-3 instrument at Argonne has recently enabled routine Kr-81 dating. The instrument is based on Atom Trap Trace Analysis (ATTA), a novel laser based atom counting technique that allows detection of long lived noble gas radioisotopes (Kr-81, Kr-85 and Ar-39) with extremely low abundance (1E-16 to 1E-10). At the center of the instrument is a magneto-optical trap (MOT), which traps and counts only the atoms of the desired isotope. This unique feature makes ATTA free of interference from any other isotopes or molecular species. For Kr-81 dating in the age range of 150 - 1,500 kyr, the required sample size is 5 - 10 micro-L STP of krypton gas, which can be extracted from approximately 100 - 200 kg of water or 40 - 80 kg of ice. Several recent developments in our lab may lead to further improvements to the current ATTA-3 apparatus: 1) The isotopic abundance ratio between the unknown, rare isotope (either Kr-81 or Kr-85) and the stable, abundant isotope (Kr-83) is measured. Here the stable isotope serves as a control isotope. A new method has been developed that allows more accurate measurements of the control isotope Kr-83. Combined with the ability to measure the rare Kr-81 and Kr-85 isotopes, this scheme allows ATTA-3 to directly determine 81Kr/Kr and 85Kr/Kr ratios without other supplemental measurements, to reduce the overall uncertainties of the measured isotope ratios, and also to improve the long term stability of the system. 2) The current capacity of the ATTA-3 instrument is about 120 samples per year. The throughput is mainly limited by the so called 'memory effect', which is caused by the residual samples trapped in the system after each measurement. These residual samples are gradually released in subsequent measurements, causing cross-sample contaminations. In order to mitigate this problem, we wash the system with a xenon discharge for about 36 hours between measurements. This practice limits the overall sample processing speed. Preliminary

Krypton-81m imaging of the right ventricle

International Nuclear Information System (INIS)

Horn, M.; Wiztum, K.; Neveu, C.; Perkins, G.; Walsh, B.

1985-01-01

The authors report the development of a method for obtaining right-ventricular radionuclide angiograms using continuous peripheral intravenous infusion of the ultra-short-lived nuclide krypton-81m. This tracer has a half-life of 13 sec, emits a single 190-keV photon, and is extremely insoluble. During infusion into a peripheral vein, Kr-81m achieves stable count rates over the right heart, and it is essentially completely cleared by the lungs during its initial pulmonary transit. Thus no interfering activity is present in the systemic circulation. Initial studies provide excellent data on right-heart anatomy and function

Melting line of Krypton in extreme thermodynamic regimes

Directory of Open Access Journals (Sweden)

Giuffre', E

2007-01-01

Full Text Available We have performed extensive computer simulations of the thermodynamic and structural properties of the krypton rare gas modeled by the modified Buckingham exponential-6 interatomic potential. Using a new set of potential parameters, we have found a good agreement with the room temperature equation of state at very high pressure obtained by diamond anvil cell experiments. Moreover, the melting line of the model has been estimated through the Lindemann criterion; the agreement with the low-pressure experiments is excellent, whereas at higher pressure, the model poorly reproduces the typical softening of the experimental melting curve.

Four-body interaction energy for compressed solid krypton from quantum theory.

Science.gov (United States)

Tian, Chunling; Wu, Na; Liu, Fusheng; Saxena, Surendra K; Zheng, Xingrong

2012-07-28

The importance of the four-body contribution in compressed solid krypton was first evaluated using the many-body expansion method and the coupled cluster theory with full single and double excitations plus perturbative treatment of triples. All different four-atom clusters existing in the first- and second-nearest neighbor shells of face-centered cubic krypton were considered, and both self-consistent-field Hartree-Fock and correlation parts of the four-body interaction were accurately determined from the ambient conditions up to eightfold volume compression. We find that the four-body interaction energy is negative at compression ratio lower than 2, where the dispersive forces play a dominant role. With increasing the compression, the four-body contribution becomes repulsive and significantly cancels the over-softening effects of the three-body potential. The obtained equation of state (EOS) was compared with the experiments and the density-functional theory calculations. It shows that combination of the four-body effects with two- and three-body interactions leads to an excellent agreement with EOS measurements throughout the whole experimental range 0-130 GPa, and extends the prediction to 300 GPa.

Electron impact ionization of large krypton clusters

Institute of Scientific and Technical Information of China (English)

Li Shao-Hui; Li Ru-Xin; Ni Guo-Quan; Xu Zhi-Zhan

2004-01-01

We show that the detection of ionization of very large van der Waals clusters in a pulsed jet or a beam can be realized by using a fast ion gauge. Rapid positive feedback electron impact ionization and fragmentation processes,which are initially ignited by electron impact ionization of the krypton clusters with the electron current of the ion gauge, result in the appearance of a progressional oscillation-like ion spectrum, or just of a single fast event under critical conditions. Each line in the spectrum represents a correlated explosion or avalanche ionization of the clusters.The phenomena have been analysed qualitatively along with a Rayleigh scattering experiment of the corresponding cluster jet.

Phase transitions in the argon, krypton and xenon in generalized Van der Waals theory

International Nuclear Information System (INIS)

Cavalcanti, H.M.

1977-01-01

Fluid-solid like phase transitions for three monoatomic substances, argon, krypton and xenon are treated, using the extension of the Van der Waals theory to the crystalline state. The method utilized is based on 'Maxwell construction' of identical areas [pt

85 km long reach PON system using a reflective SOA-EA modulator and distributed Raman fiber amplification

NARCIS (Netherlands)

Tafur Monroy, I.; Öhman, F.; Yvind, K.; Kjaer, R.; Peucheret, C.; Koonen, A.M.J.; Jeppesen, P.

2006-01-01

We report on a bidirectional 85 km long reach PON system supported by distributed fiber Raman amplification with a record 7.5 Gb/s remote carrier modulated upstream signal by employing a reflective SOA-EA monolithically integrated circuit.

Use of krypton laser stimulation in the treatment of dry eye syndrome

Science.gov (United States)

Kecik, Tadeusz; Switka-Wieclawska, Iwona; Ciszewska, Joanna; Portacha, Lidia

1991-08-01

We''d like to present the use of krypton laser stimulation in the treatment of dry eye syndrom. 10 patients with dry eye syndrom were treated with irradiation of the lacrimal gland. Schirmer test and break up time were performed before and after therapy. After 10 days of treatment we observed higher value of secreted tear amount.

Supershort avalanche electron beam in SF_{6} and krypton

Directory of Open Access Journals (Sweden)

Cheng Zhang (章程

2016-03-01

Full Text Available Runaway electrons play an important role in the avalanche formation in nanosecond- and subnanosecond- pulse discharges. In this paper, characteristics of a supershort avalanche electron beam (SAEB generated at the subnanosecond and nanosecond breakdown in sulfur hexafluoride (SF_{6} in an inhomogeneous electric field were studied. One pulser operated at negative polarity with voltage pulse amplitude of ∼130  kV and rise time of 0.3 ns. The other pulser operated at negative polarity with voltage pulse amplitude of 70 kV and rise time of ∼1.6  ns. SAEB parameters in SF_{6} are compared with those obtained in krypton (Kr, nitrogen (N_{2}, air, and mixtures of SF_{6} with krypton or nitrogen. Experimental results showed that SAEB currents appeared during the rise-time of the voltage pulse for both pulsers. Moreover, amplitudes of the SAEB current in SF_{6} and Kr approximately ranged from several to tens of milliamps at atmospheric pressure, which were smaller than those in N_{2} and air (ranging from hundreds of milliamps to several amperes. Furthermore, the concentration of SF_{6} additive could significantly reduce the SAEB current in N_{2}-SF_{6} mixture, but it slightly affected the SAEB current in Kr-SF_{6} mixture because of the atomic/molecular ionization cross section of the gas had a much greater impact on the SAEB current rather than the electronegativity.

Relative efficacy of the argon green, argon blue-green, and krypton red lasers for 10-0 nylon subconjunctival laser suture lysis.

Science.gov (United States)

Mudgil, A V; To, K W; Balachandran, R M; Janigian, R H; Tsiaras, W G

1999-01-01

To determine the optimal wavelength for subconjunctival laser suture lysis. 130 black monofilament 10-0 nylon sutures were sewn subconjunctivally into the bare sclera of enucleated rabbit globes. The lowest energy levels facilitating laser suture lysis were determined for the argon green (514.5 NM), argon blue-green (488.0 NM, 514.5 NM), and krypton red (647.1 NM) wavelengths. In addition, absorption spectroscopy was performed on the suture material and conjunctiva using the Perkin Elmer W/VIS Lambda 2 spectrometer. Krypton red produced the fewest buttonhole defects, and it was also the most efficient energy source for suture lysis (P = 0.0001) under nontenectomized conjunctiva. Absorbance spectra studies revealed peak absorbance at 628 NM for the 10-0 nylon suture material. Based on animal and absorption spectroscopy studies, krypton red may be a safer and more efficient wavelength for subconjunctival laser suture lysis.

Adsorption and pore condensation of krypton on mesoporous silicas at 77 K

Czech Academy of Sciences Publication Activity Database

Zukal, Arnošt

2006-01-01

Roč. 92, 1-3 (2006), s. 220-226 ISSN 1387-1811 R&D Projects: GA ČR GA203/05/0197; GA MPO FT-TA/040 Institutional research plan: CEZ:AV0Z40400503 Keywords : adsorption of krypton at 77 K * capillary condensation * stability condition * restriction of mesopore filling Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.796, year: 2006

Electricité, de la production à la distribution

CERN Document Server

Pierlot, J

2002-01-01

La production, le transport et la distribution de l'énergie électrique étant devenus très abstraits et réservés aux initiés, cet article est destiné à donner une approche simpliste et une vision générale des réseaux, compréhensible de tous. Depuis la centrale de production d'électricité, au travers des lignes de transfert haute-tension, l'abaissement par transformateur et la distribution, une explication simple et schématisée permettra de comprendre de manière générale le fonctionnement de ces installations trop souvent considérées comme occultes.

The future implications of some long-lived fission product nuclides discharged to the environment in fuel reprocessing wastes

International Nuclear Information System (INIS)

Bryant, P.M.; Jones, J.A.

1972-12-01

Current reprocessing practice leads to the discharge to the environment of virtually all the krypton-85 and tritium, and a large fraction of the iodine-129, formed as fission products in reactor fuel. As nuclear power programmes expand the global inventory of these long-lived nuclides is increasing. The radiological significance of these discharges is assessed in terms of radiation exposure of various population groups during the next few decades. The results of this assessment show that krypton-85 will give higher dose rates than tritium or iodine-129, but that on conventional radiological protection criteria these do not justify taking action to remove krypton-85 from reprocessing plant effluents before the 21st century. (author)

Measurement of Kr-85 and Xe-133 as undisturbed tracers for the representing of atmospheric transport after disposal of radioactivity from nuclear facilities; Messungen von Kr-85 und Xe-133 als ungestoerte Tracer zur Darstellung atmosphaerischer Transportvorgaenge nach Freisetzung von Radioaktivitaet aus kerntechnischen Anlagen

Energy Technology Data Exchange (ETDEWEB)

Frank, G.; Steinkopff, T. [Deutscher Wetterdienst (Germany); Salvamoser, J. [Institut fuer Angewandte Isotopen-, Gas- und Umweltuntersuchungen (IGU), Woerthsee (Germany)

2016-07-01

The Deutscher Wetterdienst (DWD, German Meteorological Service) operates since 1996 a sampling and measurement device for the radioactive rare gases Kr-85 and Xe-133 in Offenbach. These measurements are embedded in the German Measurement and Information System for Monitoring Environmental Radioactivity (Integriertes Mess- und Informationssystem zur Ueberwachung der Radioaktivitaet in der Umwelt, IMIS) [1]. In addition to these measurements the DWD is sampling rare gases in Potsdam and since 2014 in Trier in cooperation with the Bundesamt fuer Strahlenschutz (Federal Office for Radiation Protection, BfS). In the frame of the Global Atmosphere Watch (GAW)-program of the WMO the DWD operated a sampling station at the Zugspitze (Schneefernerhaus) from 1999 to 2005. This location at the Zugspitze is well suited for the observation of long distance transport of Kr-85 in the higher atmosphere. The DWD in Offenbach operates a complex analytical system for the measurement of Kr-85 and Xe-133 since 1998. This system consists of sampling with first enrichment, second enrichment, gas chromatographic separation and preparation of Krypton and Xenon and measurement of Kr-85 and Xe-133. Using the example Fukushima, it is shown, that the radioactive rare gases Kr-85 and Xe-133 are well undisturbed tracers for atmospheric transport in case of a nuclear accident or routine nuclear reprocessing plants. Measurements of Xe-133, I-131, Cs-137 and Kr-85 are correlated with source and atmospheric transport to the sampling sites at Offenbach and Potsdam.

Nucleon transfer reactions in D.W.B.A; Les reactions de transfert d'un nucleon dans la D.W.B.A

Energy Technology Data Exchange (ETDEWEB)

Giraud, B; Picard, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-08-01

The DWBA for one nucleon transfer reaction is described as simply and completely as possible to show the possibilities and limits of this method. The extraction of spectroscopic factors is described in the appendix. (authors) [French] Le formalisme de la DWBA est decrit d'une maniere aussi simple et complete que possible pour mettre en evidence les possibilites et les limites de cette methode d'analyse des reactions de transfert. L'extraction des facteurs spectroscopiques est exposee en appendice. (auteurs)

Distribution of the blood flow supplied by the vertebral artery in humans as assessed by emission CT

International Nuclear Information System (INIS)

Taki, W.; Handa, H.; Higa, T.; Tanada, S.; Fukuyama, H.; Fujita, T.; Yonekawa, Y.; Kameyama, M.; Torizuka, K.

1984-01-01

Though unilateral blood distribution of the vertebral artery has not been studied in humans, it is significant when considering the ischemic events especially embolic occlusion in vertebrobasilar system. To clarify the blood distribution, Krypton-81m was continuously infused into the vertebral arteries of 10 patients. Radioactivity was recorded by a rotating gamma camera. The perfusion images, reconstructed by computer in the transaxial plane, were classified according to whether the distribution was equal, or predominantly unilateral. Overlapping of blood supply from each vertebral artery was studied. In addition, the perfusion from one of the vertebral arteries revealed four distribution patterns with respect to laterality. A) ipsilateral; B) contralateral; C) bilateral; D) mosaic. Images obtained following perfusion of the vertebral artery show less uniformity compared to that of the internal carotid artery, suggesting a complicated vascular supply of the vertebral basilar territory. This complex distribution can be classified by the use of continuous infusion of Krypton-81m

Krypton excimer laser oscillation by discharge pumping

International Nuclear Information System (INIS)

Shirai, Takahiro; Tabe, Yoshitaka; Kubodera, Shoichi; Sasaki, Wataru; Kawanaka, Junji

2001-01-01

We have demonstrated vacuum ultraviolet (VUV) laser oscillation of the krypton excimer (Kr 2 *) excited by a compact self-sustained discharge device. We have observed a spectral narrowing of the Kr 2 * emission centered at 147.8 nm. A deconvoluted spectral width is 0.5 nm (FWHM), which reveals a contrast to a 13 nm spectral width of the spontaneous emission. The Kr 2 * intensity has increased one order of magnitude when a charging voltage was increased larger than 29 kV. The success of the lasing in the VUV spectral region has been attributed to the success of a stable glow discharge of Kr at 10 atm. The pulse width of the VUV laser radiation is 400 ns (FWHM). The maximum output energy measured is as large as 150 μJ. (author)

Carbon nanotubes allow capture of krypton, barium and lead for multichannel biological X-ray fluorescence imaging.

Science.gov (United States)

Serpell, Christopher J; Rutte, Reida N; Geraki, Kalotina; Pach, Elzbieta; Martincic, Markus; Kierkowicz, Magdalena; De Munari, Sonia; Wals, Kim; Raj, Ritu; Ballesteros, Belén; Tobias, Gerard; Anthony, Daniel C; Davis, Benjamin G

2016-10-26

The desire to study biology in situ has been aided by many imaging techniques. Among these, X-ray fluorescence (XRF) mapping permits observation of elemental distributions in a multichannel manner. However, XRF imaging is underused, in part, because of the difficulty in interpreting maps without an underlying cellular 'blueprint'; this could be supplied using contrast agents. Carbon nanotubes (CNTs) can be filled with a wide range of inorganic materials, and thus can be used as 'contrast agents' if biologically absent elements are encapsulated. Here we show that sealed single-walled CNTs filled with lead, barium and even krypton can be produced, and externally decorated with peptides to provide affinity for sub-cellular targets. The agents are able to highlight specific organelles in multiplexed XRF mapping, and are, in principle, a general and versatile tool for this, and other modes of biological imaging.

Energy transfer moments in thermalization; Les moments dei transfert d'energie en thermalisation

Energy Technology Data Exchange (ETDEWEB)

Soule, J L; Pillard, D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

For all moderators of the 'incoherent gaussian' type, it is possible to calculate, at any temperature, the energy transfer moments as a function of the incident energy without having to use the differential sections. Integral formulae are derived for the integral cross-section, the first and the second moment, which make it possible to tabulate directly these three functions in a few minutes calculation on IBM 7094, for the most part models proposed in the literature for the common moderators. (authors) [French] Pour tous les moderateurs de type 'incoherent gaussien' on peut calculer, a n'importe quelle temperature, les moments de transfert d'energie en fonction de l'energie incidente, sans passer par l'intermediaire des sections differentielles. On developpe des formules integrales pour la section efficace integrale, le premier et le second moment, qui permettent de tabuler directement ces trois fonctions en quelques minutes de calcul sur IBM 7094, pour la plupart des modeles proposes dans la litterature pour les moderateurs usuels. (auteurs)

Iodine, krypton and xenon retention efficiencies of silver impregnated silica gel media with different silver loadings and under different test conditions

International Nuclear Information System (INIS)

Motes, B.G.; Fernandez, S.J.; Tkachyk, J.W.

1983-02-01

The purpose of an independent study conducted by Exxon Nuclear Idaho, Co. (ENICO) was to evaluate a silver impregnated silica gel adsorption medium associated with a radioiodine air sampler developed at Brookhaven National Laboratory (BNL). Specifically, ENICO's responsibility was to evaluate the iodine and noble gas retention efficiencies of the adsorption medium. The evaluation was comprised of a four-phase program: 1) test assemblies capable of challenging the silver silica gel filled adsorber canister with radioiodine species or noble gases at flow rates up to 10 scfm and relative humidities up to 83% were constructed; 2) more than 45 kgs of the 4 and 8% silver impregnated silica gel were prepared and characterized for particle size distribution, bulk silver content, bulk density, and silver content by particle size; 3) iodine species retention efficiencies of the silver silica gel were determined; and 4 krypton and xenon retention efficiencies were measured. The iodine species retention efficiencies were greater than 90% under most conditions. A combination of flow rates >5 scfm and 4% silver loaded silica gel reduced the methyl iodide retention efficiency to less than 90%. The retention efficiencies for both krypton and xenon were on the order of 8 x 10 -2 % and were not affected greatly by any test variable except test duration. A reduced retention efficiency with increased test durations indicates adsorption equilibrium may be established within five minutes. (author)

Conceptual design of krypton recovery plant by porous membrane method

International Nuclear Information System (INIS)

Yoshida, Hiroshi; Fujine, Sachio; Shimizu, Toku; Saito, Keiichiro; Ouchi, Misao

1979-10-01

A conceptual design of a krypton recovery plant by porous membrane method was made to study feasibility of treating fuel reprocessing off-gas. Specifications of the plant could be clarified, such as off-gas pretreatment system, first cascade system of gaseous diffusion Hertz cascade composed of two-compartment diffusers, storage system, shield and housing and operating conditions. Capital costs and operating costs of the plant were estimated for different operating conditions and cost parameters. Technical and economic feasibility of the method compares favorably with those of the cryogenic distillation or the solvent absorption method. (author)

Nucleon transfer reactions in D.W.B.A; Les reactions de transfert d'un nucleon dans la D.W.B.A

Energy Technology Data Exchange (ETDEWEB)

Giraud, B.; Picard, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-08-01

The DWBA for one nucleon transfer reaction is described as simply and completely as possible to show the possibilities and limits of this method. The extraction of spectroscopic factors is described in the appendix. (authors) [French] Le formalisme de la DWBA est decrit d'une maniere aussi simple et complete que possible pour mettre en evidence les possibilites et les limites de cette methode d'analyse des reactions de transfert. L'extraction des facteurs spectroscopiques est exposee en appendice. (auteurs)

Prototype tests for the liquid Krypton, Calorimeter of the CP-violation Experiment NA48

CERN Document Server

Viehauser, Georg

This work 1s the result of a one year stay as a technical student in the NA48 group at the European Center for Nuclear Research CERN from May 1992 to May 1993. The NA48 experiment is a fixed target experiment at the CERN Super Proton Synchrotron (SPS) to study direct CP violation in neutral kaon decays. The aim of the experiment is the measurement of the ratio of the CP violation parameters £ '/£. Chapter 1 will explain the origin of these parameters and our current knowledge of their size. Chapter 2 will give a description of the NA48 experiment. A crucial part of the experiment will be a photon calorimeter filled with liquid krypton. It has to meet very ambitious demands concerning the high rate capability and the energy, space and time resolutions. In chapter 3 the principles of electromagnetic calorimetry and ionization chambers are reviewed. In 1992 two test beam exposures of a prototype of the liquid krypton calorimeter were performed. A description of these tests will be given in chapter 4. During th...

Dealuminization treatment effect of krypton gas adsorption on zeolite

International Nuclear Information System (INIS)

Shin, J. M.; Shin, S. W.; Park, J. J.; Lee, H. H.; Yang, M. S.

2003-01-01

During the OREOX process of DUPIC fuel fabrication, krypton is released as a noble fission gas. In order to treat Kr safely, adsorption method on solids havs been selected. In order to determine the optimum extraction conditions of zeolite for Kr adsorption, the preliminary experiments for the concentration of hydrochloric acid were conducted. It was found that zeolite treated with 2N hydrochloric acid solution is superior to the zeolite untreated with HCl solution. When the zeolite was treated with 2N hydrochloric acid, it was found that the surface area was decreased. The micropores and the pore volume were increased and the adsorption amount of Kr gas was increased

An experimental study on choroidal neovascularization induced by Krypton laser in rat model.

Science.gov (United States)

Cui, Jing; Liu, Yuanyuan; Zhang, Jingkai; Yan, Hua

2014-01-01

The purpose of this work was to study the efficacy and safety of choroidal neovascularization (CNV) formation induced by Krypton laser in Brown Norway (BN) rats, and observe the trend of the change of CNV after laser photocoagulation. Twenty-five male BN rats were involved in this study. Two eyes of one rat without any laser photocoagulation were randomly selected as the control group, and the other 48 eyes of 24 rats were selected as the experimental group. Eight eyes of four rats were randomly selected to receive the examinations of fundus fluorescein angiography (FFA), histopathology, and transmission electron microscopy 3, 7, 14, 21, 28, and 56 days after laser photocoagulation. After laser photocoagulation, the leakage appeared in burns on day 7 (59%), reached the peak on day 21 (84%), (p0.05). The thickness of CNV increased from day 7 to day 21 (p0.05). The experimental model of CNV can be successfully induced by Krypton laser in rats with a stable, long-lasting, and high success rate. After laser photocoagulation, the leakages appear on day 7, reach the peak on day 21, and remain stable after day 21.

Laser microsampling method for determination of retained fission gas in irradiated nuclear fuels

International Nuclear Information System (INIS)

Graczyk, D.G.; Bandyopadhyay, G.; Gehl, S.M.; Hughes, J.P.; Goodspeed, H.T.

1979-10-01

A small ruby laser adapted to fire through a microscope is used to release fission gases from specific sites on a plane surface of an irradiated fuel specimen. Interaction of the focused laser pulse with the specimen surface results in a conical crater from which sampled material has been vaporized; the crater is surrounded by a heat-affected zone in which intergranular fracture and grain separation allow release of grain-boundary gases. Procedures for measuring the amount of krypton-85 released by laser heating and the volume of material from which the release occurred are presented. The data obtained may be used to obtain local krypton fission-gas concentrations and the intragranular/intergranular distribution

De la parcelle au bassin versant : quelles données pour la modélisation du transfert des pesticides ?

OpenAIRE

Queyrel, Wilfried; Schott, Céline; Habets, Florence; Ripoche, Dominique; Launay, Marie; Tallec, Gaëlle; Ansart , P.; Blanchoud, Hélène

2015-01-01

La Directive Cadre sur l'Eau suppose la mise en œuvre par les pays membres de l'union européenne de la préservation ou la restauration d'une eau de "bonne qualité" pour les grandes masses d'eau. Cependant, les études réalisées sur le transfert des pesticides restent encore insuffisantes pour évaluer la vulnérabilité des eaux de surface et souterraines. La difficulté réside dans la diversité des molécules utilisées et de leurs propriétés physico-chimiques qui imposent que chaque substance acti...

Evolution du génome des Streptomyces : transfert horizontal et variabilité des extrémités chromosomiques

OpenAIRE

Choulet, Frédéric

2006-01-01

L'analyse et la comparaison des génomes permettent d'appréhender les forces évolutives à la base de leur dynamique et les contraintes qui s'opposent à la variabilité. Chez les bactéries, le transfert horizontal joue un rôle majeur dans leur diversification. Ce travail traite de l'évolution du génome des Streptomyces qui sont des bactéries du sol responsables de la biosynthèse d'une très grande diversité de composés actifs. Leur intérêt applicatif est considérable et touche des domaines variés...

Shakespeare dans le Brésil du 19e siècle : un exemple de transfert culturel

OpenAIRE

Segurado, Livia

2015-01-01

Partant de l’Angleterre vers l’Europe continentale au 18ème siècle, les pièces de Shakespeare arrivent au Brésil au 19ème siècle via des modèles français. Ce transfert culturel se fait d’abord par la perception de la culture étrangère imposée au Brésil lors de sa colonisation, suivie d’une graduelle interaction avec elle, puis d’une réinvention adaptée à la couleur locale. L’acteur João Caetano débute en 1835 une approche plus nationaliste, mais c’est la littérature qui voit surgir un authent...

Measurement of Kr-85 and Xe-133 as undisturbed tracers for the representing of atmospheric transport after disposal of radioactivity from nuclear facilities

International Nuclear Information System (INIS)

Frank, G.; Steinkopff, T.; Salvamoser, J.

2016-01-01

The Deutscher Wetterdienst (DWD, German Meteorological Service) operates since 1996 a sampling and measurement device for the radioactive rare gases Kr-85 and Xe-133 in Offenbach. These measurements are embedded in the German Measurement and Information System for Monitoring Environmental Radioactivity (Integriertes Mess- und Informationssystem zur Ueberwachung der Radioaktivitaet in der Umwelt, IMIS) [1]. In addition to these measurements the DWD is sampling rare gases in Potsdam and since 2014 in Trier in cooperation with the Bundesamt fuer Strahlenschutz (Federal Office for Radiation Protection, BfS). In the frame of the Global Atmosphere Watch (GAW)-program of the WMO the DWD operated a sampling station at the Zugspitze (Schneefernerhaus) from 1999 to 2005. This location at the Zugspitze is well suited for the observation of long distance transport of Kr-85 in the higher atmosphere. The DWD in Offenbach operates a complex analytical system for the measurement of Kr-85 and Xe-133 since 1998. This system consists of sampling with first enrichment, second enrichment, gas chromatographic separation and preparation of Krypton and Xenon and measurement of Kr-85 and Xe-133. Using the example Fukushima, it is shown, that the radioactive rare gases Kr-85 and Xe-133 are well undisturbed tracers for atmospheric transport in case of a nuclear accident or routine nuclear reprocessing plants. Measurements of Xe-133, I-131, Cs-137 and Kr-85 are correlated with source and atmospheric transport to the sampling sites at Offenbach and Potsdam.

Iodine, krypton and xenon retention efficiencies of silver impregnated silica gel media with different silver loadings and under different test conditions

Energy Technology Data Exchange (ETDEWEB)

Motes, B G; Fernandez, S J; Tkachyk, J W

1983-02-01

The purpose of an independent study conducted by Exxon Nuclear Idaho, Co. (ENICO) was to evaluate a silver impregnated silica gel adsorption medium associated with a radioiodine air sampler developed at Brookhaven National Laboratory (BNL). Specifically, ENICO's responsibility was to evaluate the iodine and noble gas retention efficiencies of the adsorption medium. The evaluation was comprised of a four-phase program: 1) test assemblies capable of challenging the silver silica gel filled adsorber canister with radioiodine species or noble gases at flow rates up to 10 scfm and relative humidities up to 83% were constructed; 2) more than 45 kgs of the 4 and 8% silver impregnated silica gel were prepared and characterized for particle size distribution, bulk silver content, bulk density, and silver content by particle size; 3) iodine species retention efficiencies of the silver silica gel were determined; and 4 krypton and xenon retention efficiencies were measured. The iodine species retention efficiencies were greater than 90% under most conditions. A combination of flow rates >5 scfm and 4% silver loaded silica gel reduced the methyl iodide retention efficiency to less than 90%. The retention efficiencies for both krypton and xenon were on the order of 8 x 10{sup -2}% and were not affected greatly by any test variable except test duration. A reduced retention efficiency with increased test durations indicates adsorption equilibrium may be established within five minutes. (author)

氪气产品氧含量超标的分析及处理%Analysis and treatment of exceedance of oxygen content in gaseous krypton product

Institute of Scientific and Technical Information of China (English)

葛军; 陈颂; 高波

2012-01-01

During operation of krypton xenon fine extraction unit, the poor heat exchange effect of heat exchanger before molecular sieve absorber and the leakage of inlet of molecular sieve absorber leads to exceedance of oxygen content in gaseous krypton product. After elimination troubles with corresponding corrective measures, the krypton xenon fine extraction unit steadily runs and the quality of gaseous krypton product conforms to state standards. The flow process of krypton xenon fine extraction unit is briefed, the cause analysis, treatment scheme and its effects are detailed and finally the lessons are summarized.%在氪氙精提取装置运行过程中，由于分子筛吸附器前的换热器换热效果不理想和分子筛吸附器入口泄漏等原因，导致氪气产品中的氧含量超标。采取相应措施排除故障后，保证了氪氙精提取装置的稳定运行，使氪气产品质量达到了国家标准的要求。简介氪氙精提取装置的流程，详细介绍原因分析过程和处理方案的实施及其效果，最后总结由此获得的体会。

Development of laser-based resonance ionization techniques for 81-Kr and 85-Kr measurements in the geosciences, II. December 1, 1994 through December 31, 2000 reporting period. Final technical report for Grant No. DE-FG05-95ER14497

Energy Technology Data Exchange (ETDEWEB)

Thonnard, Norbert; McKay, Larry D.; Labotka, Theodore C.

2001-02-05

A facility for measurement of rare Kr-81 and Kr-85 isotope concentration in hydrogeologic samples, and isotopic composition of minute quantities of krypton and xenon from extraterrestrial samples, was established, requiring refinement of an emerging mass spectrometric-based analytical technique and securing of laboratory space and equipment. The analytical process consists of (1) collecting a groundwater sample, (2) degassing the water, (3) separating Kr from the recovered gases, (4&5) two isotopic enrichments to reduce interfering isotopes by E9, and (6) detecting the rare krypton isotope in a unique time-of-flight mass spectrometer detecting as few as 100 Kr atoms. All equipment is installed and operating, with only some additional adjustment and testing of the last step (6, above) remaining to be completed. Collaborations have been established with a number of researchers and organizations world wide, and both groundwater and extraterrestrial samples have been collected. Completion of analyses awaits full operation of step 6.

Shape Coexistence In Light Krypton Isotopes

International Nuclear Information System (INIS)

Clement, E.; Goergen, A.; Bouchez, E.; Chatillon, A.; Korten, W.; Le Coz, Y.; Theisen, Ch.; Huerstel, A.; Lucas, R.; Wilson, J.N.; Andreoiu, C.; Butler, P.; Herzberg, R.-D.; Iwanicki, J.; Jenkins, D.; Jones, G.; Becker, F.; Gerl, J.; Blank, B.; Hannachi, F.

2005-01-01

Shape coexistence in the light krypton isotopes was studied in a series of experiments at GANIL using various experimental techniques. A new low-lying 0+ state, a so-called shape isomer, was found in delayed conversion-electron spectroscopy after fragmentation reactions. The systematics of such low-lying 0+ states suggests that the ground states of the isotopes 78Kr and 76Kr have prolate deformation, while states with prolate and oblate shape are practically degenerate and strongly mixed in 74Kr, and that the oblate configuration becomes the ground state in 72Kr. This scenario was tested in experiments performing low-energy Coulomb excitation of radioactive 76Kr and 74Kr beams from the SPIRAL facility. Both transitional and diagonal electromagnetic matrix elements were extracted from the observed γ-ray yields. The results find the prolate shape for the ground-state bands in 76Kr and 74Kr and an oblate deformation for the excited 2 2 + state in 74Kr, confirming the proposed scenario of shape coexistence

Selective scanning of the right ventricle with the ultrashort-lived isotope krypton-81m

International Nuclear Information System (INIS)

Horn, M.; Witztum, K.; Neveu, C.; Perkins, G.

1985-01-01

The measurement of right ventricular function using /sup 99m/Tc gated blood-pool imaging is hampered by the difficulty in separating the right ventricle from the left heart as well as from the right atrium. Krypton-81m, an ultrashort-lived isotope (t/sub 1/2/, 13 sec) with a single 190-keV gamma ray, can be infused into the venous circulation to yield stable count rates over the right heart. The authors have developed a technique for delivering a continuous infusion of /sup 81m/Kr via an antecubital vein for gated right ventricle (RV) equilibrium studies. Preliminary rest studies have been performed in 15 normal subjects ranging in age from 23 to 62 years. Right-heart structures including the right atrium, tricuspid valve, right ventricle, pulmonic valve, and pulmonary outflow tract are clearly identifiable. Essentially no counts are present over the left heart. RV ejection fractions in this group averaged 48.3 (+/- 5.7)%. Changes in pulmonary blood flow distribution from supine to upright position, which may be an index of pulmonary arterial pressures, are also easily demonstrated

Vacuum Pumping Performance Comparison of Non-Evaporable Getter Thin Films Deposited Using Argon and Krypton as Sputtering Gases

CERN Document Server

Liu, Xianghong; He, Yun; Li, Yulin

2005-01-01

Owing to the outstanding vacuum performance and the low secondary electron yield, non-evaporable getter (NEG) thin film deposited onto interior walls has gained widespread acceptance and has been incorporated into many accelerator vacuum system designs. The titanium-zirconium-vanadium (T-Zr-V) NEG thin films were deposited onto the interior wall of stainless steel pipes via DC magnetron sputtering method using either argon or krypton gas as sputtering gas. Vacuum pumping evaluation tests were carried out to compare vacuum pumping performances of the Ti-Zr-V NEG thin films deposited using argon or krypton. The results showed much higher initial pumping speed for the Kr-sputtered NEG film than the Ar-sputtered film, though both films have similar activation behavior. The compositions and textures of both thin films were measured to correlate to the pumping performances.

The adsorption of argon, krypton and xenon on activated charcoal

International Nuclear Information System (INIS)

Underhill, D.W.

1996-01-01

Charcoal adsorption beds are commonly used to remove radioactive noble gases from contaminated gas streams. The design of such beds requires the adsorption coefficient for the noble gas. Here an extension of the Dubinin-Radushkevich theory of adsorption is developed to correlate the effects of temperature, pressure, concentration, and carrier gas on the adsorption coefficients of krypton, xenon, and argon on activated carbon. This model is validated with previously published adsorption measurements. It accurately predicts the equilibrium adsorption coefficient at any temperature and pressure if the potential energies of adsorption, the micropore volume, and the van der Waals constants of the gases are known. 18 refs., 4 figs

Retention of gaseous fission products in reprocessing LMFBR fuels

International Nuclear Information System (INIS)

Burch, W.D.; Yarbro, O.O.; Groenier, W.S.; Stephenson, M.J.

1976-05-01

The report is devoted to status of the development programme at the Oak Ridge National Laboratory on methods for retaining iodine-131 and 129, Krypton-85, Tritium and Carbon-14 in reprocessing LMFBR fuels. The Iodox process, Fluorocarbon absorption process and Voloxidation process are described for retention of iodine, Krypton-85 and Tritium, respectively. Flowsheets for the different processes are given and results of experimental runs in small engineering-scale equipment are reported

The NA62 Liquid Krypton calorimeter data acquisition upgrade

CERN Document Server

Hallgren, Bjorn; Piccini, Mauro; Wendler, Helmut; 10.1109/NSSMIC.2008.4774802

2009-01-01

The NA62 experiment at CERN, aiming to start data taking in 2011, intends to measure the branching ratio of extremely rare kaon decays. The existing Liquid Krypton (LKr) calorimeter of the NA48 experiment will play an essential role in the new experiment. For this reason a program for the consolidation of the LKr read-out system was launched in 2006. The first part of the program consists of updating the existing data acquisition system to a modern more reliable technology using Gigabit Ethernet and PC-farm. In the second stage the readout event rate has to be increased from 13 kHz to 1 MHz. Methods to do this, while keeping much of the existing analog system, are discussed.

Intrinsic backgrounds from Rn and Kr in the XENON100 experiment

Energy Technology Data Exchange (ETDEWEB)

Aprile, E.; Anthony, M.; Perio, P. de; Gao, F.; Goetzke, L.W.; Greene, Z.; Lin, Q.; Plante, G.; Rizzo, A.; Zhang, Y. [Columbia University, Physics Department, New York, NY (United States); Aalbers, J.; Breur, P.A.; Brown, A.; Colijn, A.P.; Decowski, M.P.; Hogenbirk, E.; Tiseni, A. [Nikhef and the University of Amsterdam, Amsterdam (Netherlands); Agostini, F. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Gran Sasso Science Institute, L' Aquila (Italy); University of Bologna, Department of Physics and Astrophysics, Bologna (Italy); INFN-Bologna (Italy); Alfonsi, M.; Geis, C.; Grignon, C.; Oberlack, U.; Scheibelhut, M.; Schindler, S. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Amaro, F.D.; Cardoso, J.M.R.; Lopes, J.A.M.; Santos, J.M.F. dos; Silva, M. [University of Coimbra, LIBPhys, Department of Physics, Coimbra (Portugal); Arneodo, F.; Benabderrahmane, M.L.; Di Giovanni, A.; Maris, I. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Barrow, P.; Baudis, L.; Galloway, M.; Kazama, S.; Kessler, G.; Kish, A.; Mayani, D.; Pakarha, P.; Piastra, F.; Wulf, J. [University of Zurich, Physik-Institut, Zurich (Switzerland); Bauermeister, B.; Calven, J.; Conrad, J.; Ferella, A.D.; Moraa, K.; Pelssers, B. [Stockholm University, AlbaNova, Oskar Klein Centre, Department of Physics, Stockholm (Sweden); Berger, T.; Brown, E.; Piro, M.C. [Rensselaer Polytechnic Institute, Department of Physics, Applied Physics and Astronomy, Troy, NY (United States); Bruenner, S.; Cichon, D.; Eurin, G.; Hasterok, C.; Lindner, M.; Marrodan Undagoitia, T.; Pizzella, V.; Rauch, L.; Rupp, N.; Schreiner, J.; Simgen, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Bruno, G.; Rosso, A.G.; Molinario, A.; Wang, Z. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Budnik, R.; Itay, R.; Landsman, H.; Lellouch, D.; Levinson, L.; Manfredini, A.; Priel, N. [Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel); Buetikofer, L.; Coderre, D.; Kaminsky, B.; Schumann, M.; Sivers, M. von [Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); Cervantes, M.; Lang, R.F.; Masson, D.; Reichard, S. [Purdue University, Department of Physics and Astronomy, West Lafayette, IN (United States); Cussonneau, J.P.; Diglio, S.; Masbou, J.; Micheneau, K.; Persiani, R.; Thers, D. [CNRS/IN2P3, Universite de Nantes, SUBATECH, IMT Atlantique, Nantes (France); Di Gangi, P.; Garbini, M.; Massoli, F.V.; Sartorelli, G.; Selvi, M. [University of Bologna, Department of Physics and Astrophysics, Bologna (Italy); INFN-Bologna (Italy); Fei, J.; Lombardi, F.; Ni, K.; Ye, J. [University of California, Department of Physics, San Diego, CA (United States); Fieguth, A.; Murra, M.; Vargas, M.; Weinheimer, C.; Wittweg, C. [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Fulgione, W. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Gran Sasso Science Institute, L' Aquila (Italy); INFN-Torino (Italy); Osservatorio Astrofisico di Torino, Torino (Italy); Lindemann, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); Messina, M. [Columbia University, Physics Department, New York, NY (United States); New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Naganoma, J.; Shagin, P. [Rice University, Department of Physics and Astronomy, Houston, TX (United States); Pienaar, J. [Purdue University, Department of Physics and Astronomy, West Lafayette, IN (United States); University of Chicago, Department of Physics, Kavli Institute of Cosmological Physics, Chicago, IL (United States); Ramirez Garcia, D. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); Reuter, C. [University of Zurich, Physik-Institut, Zurich (Switzerland); Purdue University, Department of Physics and Astronomy, West Lafayette, IN (United States); Lavina, L.S. [Universite Paris Diderot, CNRS/IN2P3, LPNHE, Universite Pierre et Marie Curie, Paris (France); Stein, A.; Wang, H. [University of California, Physics and Astronomy Department, Los Angeles, CA (United States); Trinchero, G. [INFN-Torino (Italy); Osservatorio Astrofisico di Torino, Torino (Italy); Tunnell, C. [Nikhef and the University of Amsterdam, Amsterdam (Netherlands); University of Chicago, Department of Physics, Kavli Institute of Cosmological Physics, Chicago, IL (United States); Weber, M. [Columbia University, Physics Department, New York, NY (United States); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Wei, Y. [University of Zurich, Physik-Institut, Zurich (Switzerland); University of California, Department of Physics, San Diego, CA (United States); Collaboration: XENON Collaboration

2018-02-15

In this paper, we describe the XENON100 data analyses used to assess the target-intrinsic background sources radon ({sup 222}Rn), thoron ({sup 220}Rn) and krypton ({sup 85}Kr). We detail the event selections of high-energy alpha particles and decay-specific delayed coincidences. We derive distributions of the individual radionuclides inside the detector and quantify their abundances during the main three science runs of the experiment over a period of ∝ 4 years, from January 2010 to January 2014. We compare our results to external measurements of radon emanation and krypton concentrations where we find good agreement. We report an observed reduction in concentrations of radon daughters that we attribute to the plating-out of charged ions on the negatively biased cathode. (orig.)

Intrinsic backgrounds from Rn and Kr in the XENON100 experiment

International Nuclear Information System (INIS)

Aprile, E.; Anthony, M.; Perio, P. de; Gao, F.; Goetzke, L.W.; Greene, Z.; Lin, Q.; Plante, G.; Rizzo, A.; Zhang, Y.; Aalbers, J.; Breur, P.A.; Brown, A.; Colijn, A.P.; Decowski, M.P.; Hogenbirk, E.; Tiseni, A.; Agostini, F.; Alfonsi, M.; Geis, C.; Grignon, C.; Oberlack, U.; Scheibelhut, M.; Schindler, S.; Amaro, F.D.; Cardoso, J.M.R.; Lopes, J.A.M.; Santos, J.M.F. dos; Silva, M.; Arneodo, F.; Benabderrahmane, M.L.; Di Giovanni, A.; Maris, I.; Barrow, P.; Baudis, L.; Galloway, M.; Kazama, S.; Kessler, G.; Kish, A.; Mayani, D.; Pakarha, P.; Piastra, F.; Wulf, J.; Bauermeister, B.; Calven, J.; Conrad, J.; Ferella, A.D.; Moraa, K.; Pelssers, B.; Berger, T.; Brown, E.; Piro, M.C.; Bruenner, S.; Cichon, D.; Eurin, G.; Hasterok, C.; Lindner, M.; Marrodan Undagoitia, T.; Pizzella, V.; Rauch, L.; Rupp, N.; Schreiner, J.; Simgen, H.; Bruno, G.; Rosso, A.G.; Molinario, A.; Wang, Z.; Budnik, R.; Itay, R.; Landsman, H.; Lellouch, D.; Levinson, L.; Manfredini, A.; Priel, N.; Buetikofer, L.; Coderre, D.; Kaminsky, B.; Schumann, M.; Sivers, M. von; Cervantes, M.; Lang, R.F.; Masson, D.; Reichard, S.; Cussonneau, J.P.; Diglio, S.; Masbou, J.; Micheneau, K.; Persiani, R.; Thers, D.; Di Gangi, P.; Garbini, M.; Massoli, F.V.; Sartorelli, G.; Selvi, M.; Fei, J.; Lombardi, F.; Ni, K.; Ye, J.; Fieguth, A.; Murra, M.; Vargas, M.; Weinheimer, C.; Wittweg, C.; Fulgione, W.; Lindemann, S.; Messina, M.; Naganoma, J.; Shagin, P.; Pienaar, J.; Ramirez Garcia, D.; Reuter, C.; Lavina, L.S.; Stein, A.; Wang, H.; Trinchero, G.; Tunnell, C.; Weber, M.; Wei, Y.

2018-01-01

In this paper, we describe the XENON100 data analyses used to assess the target-intrinsic background sources radon ( 222 Rn), thoron ( 220 Rn) and krypton ( 85 Kr). We detail the event selections of high-energy alpha particles and decay-specific delayed coincidences. We derive distributions of the individual radionuclides inside the detector and quantify their abundances during the main three science runs of the experiment over a period of ∝ 4 years, from January 2010 to January 2014. We compare our results to external measurements of radon emanation and krypton concentrations where we find good agreement. We report an observed reduction in concentrations of radon daughters that we attribute to the plating-out of charged ions on the negatively biased cathode. (orig.)

Heat transfer in smooth tubes, between parallel plates, along a semi-infinite plate, in annular spaces and along tube bundles for exponential distribution of the heat flux in forced, laminar or turbulent flow; Transfert de chaleur dans des tubes lisses, entre des plaques planes paralleles, le long d'une plaque plane, dans des espaces annulaires et le long de faisceaux tubulaires pour une repartition exponentielle du flux de chaleur en ecoulement force, laminaire ou turbulent

Energy Technology Data Exchange (ETDEWEB)

Graber, H [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

1969-04-01

By introducing an additional parameter F{sub 0}, the processes known hitherto for calculating heat transfer are extended to the heat flux distributions following an exponential law q{sub w} = exp(mx) which give a heat transfer coefficient, independent of position for laminar and turbulent flow with a linear pressure drop. For laminar flow along a semi-infinite plate, the heat flux distribution in accordance with the law qw = x{sup m} leads to the Nusselt number, regardless of the position. Nu is then determined by the thickness of the thermal boundary layer. For the annular space, the equations for explicit calculation of the temperature field will be given, as well as the Nusselt number in laminar flow and constant heat flux. In turbulent flow, the laws of distribution of eddy diffusivity for momentum in a tube, established by H. Reichardt, adapted for the annular space and the tube bundle, give the velocity field and the coefficient of friction and thus permit solution of the heat transfer equations. The results of the numerical calculation are given in the tables and diagrams for an extended range of the various parameters and compared with the experimental results. A simple process to determine the lower limit of the thermal entry length will be described. (author) [French] Par l'introduction d'un parametre supplementaire F{sub 0}, les procedes connus jusqu'a present pour le calcul du transfert de chaleur sont etendus aux repartitions exponentielles q{sub w} = exp(mx) du flux de chaleur qui indiquent un coefficient de transfert de chaleur independant de l'endroit pour l'ecoulement laminaire ou turbulent avec chute de pression lineaire. Pour l'ecoulement laminaire le long d'une plaque plane, la repartition du flux de chaleur selon la loi q{sub w} = x{sup m} conduit au nombre de Nusselt independant de l'endroit. Nu est alors determine par l'epaisseur de la couche limite thermique. Pour l'espace annulaire, seront indiquees les equations pour le calcul explicite du

Evaluation de l'efficacité vis-à-vis du ruissellement de surface et des transferts latéraux dans le sol de différentes options de gestion utilisant (ou non) un couvert enherbé : Application en vue de limiter la contamination des eaux par les pesticides dans le contexte du Beaujolais viticole de coteaux

OpenAIRE

Gouy, V.; Peyrard, X.; Liger, L.

2015-01-01

/ Cette étude apporte des éléments de réponse aux questions suivantes dans le contexte du Nord Beaujolais : - dans quelle mesure une zone tampon enherbée rivulaire recevant un ruissellement concentré de surface est-elle capable de réduire significativement le transfert des pesticides associés sans engendrer une contamination de nappe sous-jacente ? - dans quelle mesure une infiltration en amont en parcelle de vigne peut-elle contribuer à l'atténuation des transferts de pesticides ou engendrer...

Detection of tobacco smoke deposition by hyperpolarized krypton-83 MRI.

Science.gov (United States)

Cleveland, Zackary I; Pavlovskaya, Galina E; Stupic, Karl F; Wooten, Jan B; Repine, John E; Meersmann, Thomas

2008-02-01

Despite the importance of the tobacco smoke particulate matter in the lungs to the etiology of pulmonary disease in cigarette smokers, little is currently known about the spatial distribution of particle deposition or the persistence of the resulting deposits in humans, and no satisfactory technique currently exists to directly observe tobacco smoke condensate in airways. In this proof-of-principle work, hyperpolarized (hp) 83Kr MRI and NMR spectroscopy are introduced as probes for tobacco smoke deposition in porous media. A reduction in the hp-83Kr longitudinal (T1) relaxation of up to 95% under near-ambient humidity, pressure and temperature conditions was observed when the krypton gas was brought into contact with surfaces that had been exposed to cigarette smoke. This smoke-induced acceleration of the 83Kr self-relaxation was observed for model glass surfaces that, in some experiments, were coated with bovine lung surfactant extract. However, a similar effect was not observed with hp-(129)Xe indicating that the 83Kr sensitivity to smoke deposition was not caused by paramagnetic species but rather by quadrupolar relaxation due to high adsorption affinity for the smoke deposits. The 83Kr T1 differences between smoke-treated and untreated surfaces were sufficient to produce a strong contrast in variable flip angle FLASH hp-83Kr MRI, suggesting that hp-83Kr may be a promising contrast agent for in vivo pulmonary MRI.

Short wavelength laser calculations for electron pumping in neon-like krypton (Kr XXVII)

Science.gov (United States)

Feldman, U.; Bhatia, A. K.; Suckewer, S.

1983-01-01

Calculations of electron impact collision strengths and spontaneous radiative decay rates are made for neon-like krypton (Kr XXVII) for the 2s2 2p6, 2s2 2p5 3s, 2s2 2p5 3p, and 2s2 2p5 3d configurations. From these atomic data, the level populations as a function of the electron density are calculated at two temperatures, 1 x 10 to the 7th K and 3 x 10 to the 7th K. An analysis of level populations reveals that a volume of krypton in which a significant number of the ions are in the Kr XXVII degree of ionization can produce a significant gain in transition between the 2s2 2p5 3s and 2s2 2p5 3p configurations. At an electron density of 1 x 10 to the 19th/cu cm the plasma length has to be of the order of 1 m; at a density of 1 x 10 to the 21st/cu cm the length is reduced to approximately 0.5 cm; and at an electron density of 1 x 10 to the 22nd/cu cm the length of the plasma is further reduced to approximately 1 mm.

Laser-optogalvanic studies of the 4p5 ns and nd autoionizing resonances in krypton

International Nuclear Information System (INIS)

Baig, M A; Hanif, M; Aslam, M

2008-01-01

We report new measurements of the odd-parity autoionizing resonances in krypton using resonant two-photon excitation from the 4p 5 5s[3/2] 2 metastable level in a mild DC discharge and an optogalvanic detection technique. We have observed the 4p 5 ns [1/2] 0,1 , 4p 5 nd [3/2] 2 and 4p 5 nd [5/2] 2,3 autoionizing resonances excited from three intermediate levels 4p 5 5p' [1/2] 1 , 4p 5 5p' [3/2] 1 and 4p 5 5p' [3/2] 2 . The spectra are notable for the absence of the broad autoionizing 4p 5 nd [3/2] 1 series which dominates in the photo-absorption spectrum from the ground state. The prominent transitions follow ΔK = ΔJ = Δl selection rules of the JK-coupling scheme. We report nearly 100 new energy levels in krypton besides the quantum defects and the reduced widths Γ r Γ(ν) 3 of the nd' [3/2] 2 , nd' [5/2] 2 and nd' [5/2] 3 Rydberg states

A GCMC simulation and experimental study of krypton adsorption/desorption hysteresis on a graphite surface.

Science.gov (United States)

Prasetyo, Luisa; Horikawa, Toshihide; Phadungbut, Poomiwat; Johnathan Tan, Shiliang; Do, D D; Nicholson, D

2016-09-15

Adsorption isotherms and isosteric heats of krypton on a highly graphitized carbon black, Carbopack F, have been studied with a combination of Monte Carlo simulation and high-resolution experiments at 77K and 87K. Our investigation sheds light on the microscopic origin of the experimentally observed, horizontal hysteresis loop in the first layer, and the vertical hysteresis-loop in the second layer, and is found to be in agreement with our recent Monte Carlo simulation study (Diao et al., 2015). From detailed analysis of the adsorption isotherm, the latter is attributed to the compression of an imperfect solid-like state in the first layer, to form a hexagonally packed, solid-like state, immediately following the first order condensation of the second layer. To ensure that capillary condensation in the confined spaces between microcrystallites of Carbopack F does not interfere with these hysteresis loops, we carried out simulations of krypton adsorption in the confined space of a wedge-shaped pore that mimics the interstices between particles. These simulations show that, up to the third layer, any such interference is negligible. Copyright © 2016 Elsevier Inc. All rights reserved.

Purification of cyclotron-produced 81Rb for the preparation of small krypton-81m generators

International Nuclear Information System (INIS)

Andersen, P.; Haasbroek, F.J.; Venter, S.S.J.; Strelow, F.W.E.

1981-01-01

A method is described for the separation of 81 Rb from sodium bromide targets. Ammonium molybdophosphate columns are used and the separation takes only about 20 minutes. More than 90% of the 81 Rb is recovered. The purified 81 Rb enables small Rubidium-81/Krypton-81m generators to be prepared with Bio-Rad 50W-X8 ion-exchange resin (200-400 mesh) [af

Effect of flow rate on the adsorption coefficient of radioactive krypton on activated carbon

International Nuclear Information System (INIS)

Sun, L.S.C.; Underhill, D.W.

1981-01-01

For some time, there have been questions relative to the effect of carrier gas velocity on the adsorption coefficient for radioactive noble gases on activated charcoal. Resolution of these questions is particularly important in terms of developing standard procedures for determining such coefficients under laboratory conditions. Studies at the Harvard Air Cleaning Laboratory appear to confirm that the adsorption coefficient for radioactive krypton on activated charcoal is independent of the velocity of the carrier gas

Identification of krypton Kr XVIII to Kr XXIX spectra excited in TFR Tokamak plasmas

International Nuclear Information System (INIS)

Wyart, J.F.

1985-02-01

The emission spectrum of krypton (injected into TFR tokamak plasmas) has been recorded photographically in the 15-300 A spectral range by means of a 2m grazing incidence spectrograph. Preliminary identification work, based on isoelectronic regularities from known spectra of other ions and ionization equilibrium calculations, has allowed 48 lines (belonging to the O I, F I, Na I, Mg I, Al I, Ar I and K I sequences) to be identified

Analysis of Selected Legacy ⁸⁵Kr Samples

Energy Technology Data Exchange (ETDEWEB)

Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-02

Legacy samples composed of ⁸⁵Kr encapsulated in solid zeolite 5A material and five small metal tubes containing a mixture of the zeolite combined with a glass matrix resulting from hot isostatic pressing have been preserved. The samples were a result of krypton R&D encapsulation efforts in the late 1970s performed at the Idaho Chemical Processing Plant. These samples were shipped to Oak Ridge National Laboratory (ORNL) in mid-FY 2014. Upon receipt the outer shipping package was opened, and the inner package, removed and placed in a radiological hood. The individual capsules were double bagged as they were removed from the inner shipping pig and placed into individual glass sample bottles for further analysis. The five capsules were then x-ray imaged. Capsules 1 and 4 appear intact and to contain an amorphous mass within the capsules. Capsule 2 clearly shows the saw marks on the capsule and a quantity of loose pellet or bead-like material remaining in the capsule. Capsule 3 shows similar bead-like material within the intact capsule. Capsule 5 had been opened at an undetermined time in the past. The end of this capsule appears to have been cut off, and there are additional saw marks on the side of the capsule. X-ray tomography allowed the capsules to be viewed along the three axes. Of most interest was determining whether there was any residual material in the closed end of Capsule 5. The images confirmed the presence of residual material within this capsule. The material appears to be compacted but still retains some of the bead-like morphology. Based on the nondestructive analysis (NDA) results, a proposed path forward was formulated to advance this effort toward the original goals of understanding the effects of extended storage on the waste form and package. Based on the initial NDA and the fact that there are at least two breached samples, it was proposed that exploratory tests be conducted with the breached specimens before opening the three intact

Age influence on retention, distribution and internal doses of 85Sr in rat

International Nuclear Information System (INIS)

Tian Wuxun; Wang Decheng; Zhang Hongyuan

1990-01-01

After I.V. 85 Sr, the whole body 85 Sr-retentions in rats were fit to two compartment exponential equations. The equation parameters showed a significantly difference between the young group and both the adult and old groups (p 2 ) for 85 Sr in the slow compartment decreased in regular order from the young to the old groups. In the bone 85 Sr-retention equations Tb 2 of the slow compartment for 85 Sr in the young group was significantly lower than the adult and old groups. The doses of the whole body and red-marrow for young rats were 4.2 times as much as those of adult rats, and 6.2 and 5.9 times as much as those old rats. The dose-cumulative speeds was most quick in the young groups and similar in the adult and the old

Heat transfer in smooth tubes, between parallel plates, along a semi-infinite plate, in annular spaces and along tube bundles for exponential distribution of the heat flux in forced, laminar or turbulent flow; Transfert de chaleur dans des tubes lisses, entre des plaques planes paralleles, le long d'une plaque plane, dans des espaces annulaires et le long de faisceaux tubulaires pour une repartition exponentielle du flux de chaleur en ecoulement force, laminaire ou turbulent

Energy Technology Data Exchange (ETDEWEB)

Graber, H. [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

1969-04-01

By introducing an additional parameter F{sub 0}, the processes known hitherto for calculating heat transfer are extended to the heat flux distributions following an exponential law q{sub w} = exp(mx) which give a heat transfer coefficient, independent of position for laminar and turbulent flow with a linear pressure drop. For laminar flow along a semi-infinite plate, the heat flux distribution in accordance with the law qw = x{sup m} leads to the Nusselt number, regardless of the position. Nu is then determined by the thickness of the thermal boundary layer. For the annular space, the equations for explicit calculation of the temperature field will be given, as well as the Nusselt number in laminar flow and constant heat flux. In turbulent flow, the laws of distribution of eddy diffusivity for momentum in a tube, established by H. Reichardt, adapted for the annular space and the tube bundle, give the velocity field and the coefficient of friction and thus permit solution of the heat transfer equations. The results of the numerical calculation are given in the tables and diagrams for an extended range of the various parameters and compared with the experimental results. A simple process to determine the lower limit of the thermal entry length will be described. (author) [French] Par l'introduction d'un parametre supplementaire F{sub 0}, les procedes connus jusqu'a present pour le calcul du transfert de chaleur sont etendus aux repartitions exponentielles q{sub w} = exp(mx) du flux de chaleur qui indiquent un coefficient de transfert de chaleur independant de l'endroit pour l'ecoulement laminaire ou turbulent avec chute de pression lineaire. Pour l'ecoulement laminaire le long d'une plaque plane, la repartition du flux de chaleur selon la loi q{sub w} = x{sup m} conduit au nombre de Nusselt independant de l'endroit. Nu est alors determine par l'epaisseur de la couche limite thermique. Pour l'espace annulaire, seront

Generation of spectrally stable 6.5-fs visible pulses via filamentation in krypton

Institute of Scientific and Technical Information of China (English)

Keisuke Kaneshima; Kengo Takeuchi; Nobuhisa Ishii; Jiro Itatani

2016-01-01

We produced 5-μJ, 6.5-fs visible pulses at a repetition rate of 1 kHz using filamentation in a gas cell filled with krypton followed by spectral selection and phase compensation by a combination of dielectric mirrors. The visible pulses have a smooth spectrum from 520 to 650 nm with a shot-to-shot stability in each spectral component of better than 2%(standard deviation). This pulse compression scheme is simple and robust, and can be easily integrated into intense ultrashort-pulse laser systems.

The evaluation of right ventricular performance using krypton-81m

International Nuclear Information System (INIS)

Ham, H.R.; Piepsz, A.; Vandevivere, J.; Guillaume, M.; Goethals, P.; Lenaers, A.

1983-01-01

The availability of krypton-81m suitable for intravenous injection provides an easy means for assessing right ventricular function. The superimposition of the other heart chambers does not constitute a problem. The activity in the left heart is negligible and the study can be performed in the right anterior oblique position to obtain optimal separation between the right atrium and the right ventricle. Lung activity is quite high and should be corrected before computing the right ventricular ejection fraction. This correction can be accomplished by performing Tc-99m MAA perfusion scintigraphy. The measurement of the right ventricular ejection fraction appears to be reproducible with very small inter-and intraobserver variability. Good quality phase and amplitude images can be obtained with such high count rates

High-energy krypton fluoride lasers for inertial fusion.

Science.gov (United States)

Obenschain, Stephen; Lehmberg, Robert; Kehne, David; Hegeler, Frank; Wolford, Matthew; Sethian, John; Weaver, James; Karasik, Max

2015-11-01

Laser fusion researchers have realized since the 1970s that the deep UV light from excimer lasers would be an advantage as a driver for robust high-performance capsule implosions for inertial confinement fusion (ICF). Most of this research has centered on the krypton-fluoride (KrF) laser. In this article we review the advantages of the KrF laser for direct-drive ICF, the history of high-energy KrF laser development, and the present state of the art and describe a development path to the performance needed for laser fusion and its energy application. We include descriptions of the architecture and performance of the multi-kilojoule Nike KrF laser-target facility and the 700 J Electra high-repetition-rate KrF laser that were developed at the U.S. Naval Research Laboratory. Nike and Electra are the most advanced KrF lasers for inertial fusion research and energy applications.

Ultrafast quantum control of ionization dynamics in krypton.

Science.gov (United States)

Hütten, Konrad; Mittermair, Michael; Stock, Sebastian O; Beerwerth, Randolf; Shirvanyan, Vahe; Riemensberger, Johann; Duensing, Andreas; Heider, Rupert; Wagner, Martin S; Guggenmos, Alexander; Fritzsche, Stephan; Kabachnik, Nikolay M; Kienberger, Reinhard; Bernhardt, Birgitta

2018-02-19

Ultrafast spectroscopy with attosecond resolution has enabled the real time observation of ultrafast electron dynamics in atoms, molecules and solids. These experiments employ attosecond pulses or pulse trains and explore dynamical processes in a pump-probe scheme that is selectively sensitive to electronic state of matter via photoelectron or XUV absorption spectroscopy or that includes changes of the ionic state detected via photo-ion mass spectrometry. Here, we demonstrate how the implementation of combined photo-ion and absorption spectroscopy with attosecond resolution enables tracking the complex multidimensional excitation and decay cascade of an Auger auto-ionization process of a few femtoseconds in highly excited krypton. In tandem with theory, our study reveals the role of intermediate electronic states in the formation of multiply charged ions. Amplitude tuning of a dressing laser field addresses different groups of decay channels and allows exerting temporal and quantitative control over the ionization dynamics in rare gas atoms.

Noble Liquid (Xenon or Krypton) Totally Active Calorimetry

CERN Multimedia

2002-01-01

Main Goals\\\\ \\\\ Determine ionization and scintillation yields in liquid Xenon (LXe) or Krypton.\\\\ \\\\ Determine the electron lifetime and photon mean free path in LXe or LKr. \\\\ \\\\ Determine energy resolution of LXe or LKr via ionization or scintillation.\\\\ \\\\ Determine correlation of fluctuations between ionization and scintillation. Summary of Results \\\\ \\\\ -~measured the electron lifetime in LXe, ($\\tau$~$>$~400 $\\mu$s).\\\\ \\\\ -~measured the energy to create an ionization electron in LXe, W=9.8 eV.\\\\ \\\\ -~measured the energy to create a LXe scintillation photon, W$ _{s} $~=~14.2~eV. \\\\ \\\\ -~measured the anticorrelation of scintillation and ionization yields. \\\\ \\\\ -~measured the energy resolution in LXe via ionization, $ sigma _{E} / $E=0.07\\%/$\\sqrt$E(GeV). \\\\ \\\\ -~measured resolution in LXe via scintillation $ sigma _{E} / $E=0.24\\%/$\\sqrt$E(GeV)+0.26\\%. \\\\ \\\\ -~measured electron drift velocity in LXe:~neat (2.5 mm/$\\mu$s), doped (4.4~mm/$\\mu$s). \\\\ \\\\ -~measured the photon mean free path in LXe vs $ lambd...

Two-photon resonant, stimulated processes in krypton and xenon

International Nuclear Information System (INIS)

Miller, J.C.

1988-11-01

Both on-axis and conical emissions have been observed following two-photon pumping of the 5p states of krypton and the 6p', 7p, 8p, and 4f states of xenon. In the former case, coherent emissions from the 5p states to the 5s are observed, and in the latter case, many p→s, d→p, and f→d cascade emissions are observed. By analogy to the well-studied alkali and alkaline earth examples, the emissions are discussed in terms of amplified spontaneous emission (ASE), stimulated hyper-Raman scattering, and parametric four-wave mixing. The physical processes responsible for the conical emission and for intensity anomalies in the xenon p→s emissions are not understood at present. Interference effects due to coherent cancellation between competing excitation pathways may be occurring. 4 refs., 3 figs

Improved modeling of two-dimensional transitions in dense phases on crystalline surfaces. Krypton-graphite system.

Science.gov (United States)

Ustinov, E A

2015-02-21

This paper presents a refined technique to describe two-dimensional phase transitions in dense fluids adsorbed on a crystalline surface. Prediction of parameters of 2D liquid-solid equilibrium is known to be an extremely challenging problem, which is mainly due to a small difference in thermodynamic functions of coexisting phases and lack of accuracy of numerical experiments in case of their high density. This is a serious limitation of various attempts to circumvent this problem. To improve this situation, a new methodology based on the kinetic Monte Carlo method was applied. The methodology involves analysis of equilibrium gas-liquid and gas-solid systems undergoing an external potential, which allows gradual shifting parameters of the phase coexistence. The interrelation of the chemical potential and tangential pressure for each system is then treated with the Gibbs-Duhem equation to obtain the point of intersection corresponding to the liquid/solid-solid equilibrium coexistence. The methodology is demonstrated on the krypton-graphite system below and above the 2D critical temperature. Using experimental data on the liquid-solid and the commensurate-incommensurate transitions in the krypton monolayer derived from adsorption isotherms, the Kr-graphite Lennard-Jones parameters have been corrected resulting in a higher periodic potential modulation.

Vacuum ultraviolet emission from argon, krypton, and xenon in a radial-viewed theta pinch

International Nuclear Information System (INIS)

Engleman, R. Jr.; Thomson, D.B.; Monaghan, D.A.

1976-03-01

Vacuum ultraviolet line emission from argon, krypton, and xenon (5 percent in deuterium) has been observed from a plasma (approximately 50 eV and N/sub e/ approximately 10 17 /cm 3 ) produced by the Scyllar linear theta-pinch device. More than 50 emission lines in the 30- to 500-A region have been measured for each gas mixture. Some lines have been identified as due to Ar VII through XI, Kr IX and X, and Xe IX, but many lines remain unassigned

Comparison of Medium Power Hall Effect Thruster Ion Acceleration for Krypton and Xenon Propellants

Science.gov (United States)

2016-09-14

Pumping is provided by four single-stage cryogenic panels (single-stage cold heads at 25 K) and one 50 cm two stage cryogenic pump (12 K). This vacuum...test chamber has a mea- sured pumping speed of 36 kL/s on xenon. The Hall thruster used in this study is a medium power laboratory Hall effect...The first compo- nent passes through a krypton opto-galvanic cell and is terminated by a beam dump . The opto-galvanic cell current is capacitively

Clinical use of ultrashort-lived radionuclide krypton-81m for noninvasive analysis of right ventricular performance in normal subjects and patients with right ventricular dysfunction

International Nuclear Information System (INIS)

Nienaber, C.A.; Spielmann, R.P.; Wasmus, G.; Mathey, D.G.; Montz, R.; Bleifeld, W.H.

1985-01-01

The ultrashort-lived radionuclide krypton-81m, eluted in 5% dextrose from a bedside rubidium-81m generator, was intravenously infused for rapid imaging of the right-sided heart chambers in the right anterior oblique projection adjusted for optimal right atrioventricular separation. Left-sided heart and lung background was minimized by rapid decay and efficient exhalation of krypton-81m, requiring no algorithm for background correction. A double region of interest method decreased the variability in the assessment of ejection fraction to 5%. In 10 normal subjects, 11 patients with pulmonary hypertension, 4 patients with right ventricular outflow tract obstruction and 4 patients with right ventricular infarction, right ventricular ejection fraction determined by krypton-81m equilibrium blood pool imaging ranged from 14 to 76%. The correlation between these values and those determined by cineangiography according to Simpson's rule was close: r . 0.93 for all data points, r . 0.92 for studies at rest and r . 0.93 for exercise studies. Exercise-related changes in right ventricular function revealed a disturbed functional reserve with pulmonary hypertension and right ventricular infarction, whereas in compensated right ventricular outflow tract obstruction there was a physiologic increase in ejection fraction with exercise. Thus, equilibrium-gated right ventricular imaging using ultrashort-lived krypton-81m is a simple, accurate and reproducible method with potential for serial assessment of right ventricular ejection fraction in a variety of right ventricular anatomic and functional abnormalities, both at rest and during exercise. Advantages of this method include an extremely low radiation dose to patients and clear right atrioventricular separation without the need to correct for background activity

Near-field krypton-85 measurements in stable meteorological conditions around the AREVA NC La Hague reprocessing plant: estimation of atmospheric transfer coefficients.

Science.gov (United States)

Connan, O; Solier, L; Hébert, D; Maro, D; Lamotte, M; Voiseux, C; Laguionie, P; Cazimajou, O; Le Cavelier, S; Godinot, C; Morillon, M; Thomas, L; Percot, S

2014-11-01

The aim of this work was to study the near-field dispersion of (85)Kr around the nuclear fuel reprocessing plant at La Hague (AREVA NC La Hague - France) under stable meteorological conditions. Twenty-two (85)Kr night-time experimental campaigns were carried out at distances of up to 4 km from the release source. Although the operational Gaussian models predict for these meteorological conditions a distance to plume touchdown of several kilometers, we almost systematically observed a marked ground signal at distances of 0.5-4 km. The calculated atmospheric transfer coefficients (ATC) show values (1) higher than those observed under neutral conditions, (2) much higher than those proposed by the operational models, and (3) higher than those used in the impact assessments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Efficacy of krypton laser photodynamic therapy for oral mucosa dysplasia in 9,10-dimethyl-1,2-benzanthracene-treated hamsters.

Science.gov (United States)

Shen, Lingyue; Xu, Qing; Li, Pingping; Zhou, Guoyu

2013-11-01

The present study aimed to evaluate the efficacy of krypton laser photodynamic therapy (PDT) with PsD-007 for the treatment of oral mucosa dysplasia in 9,10-dimethyl-1,2-benzanthracene (DMBA)-treated hamsters. A DMBA-induced hamster cheek pouch model of precancerous lesions was created and the resultant 25 hamsters were divided into five groups. The right side was treated with PDT and the left side was used as the positive control. Following systemic anesthesia, an incision was made in the groin area to expose the femoral vein. PsD-007 was administered intravenously through the femoral vein. Various doses of photosensitizer were used to treat groups A-E. Subsequent to closing the incision, the right side of the buccal mucosa was irradiated with light using the krypton laser at a wavelength of 413 nm, a power density of 150 mW/cm 2 and an irradiation time of 20 min. At six weeks post-surgery, the response was analyzed using histological examinations of the buccal pouch mucosa. A total of 24 hamsters completed the six-week observation period, as one hamster from group C died in the second week following the PDT. Of all 24 irradiated sides, 15 formed normal mucosal tissues and nine demonstrated mild dysplasia. Of the total control sides, six developed moderate dysplasia, five developed severe dysplasia and 13 progressed to carcinoma in situ or squamous cell carcinoma (SCC). The results revealed a significant difference between the two sides (P10 mg/kg, there was no statistical difference (P>0.05). PsD-007-mediated krypton laser PDT is effective for the treatment of oral mucosa dysplasia in hamsters.

Effect of the fcc-hcp martensitic transition on the equation of state of solid krypton up to 140 GPa

Science.gov (United States)

Rosa, A. D.; Garbarino, G.; Briggs, R.; Svitlyk, V.; Morard, G.; Bouhifd, M. A.; Jacobs, J.; Irifune, T.; Mathon, O.; Pascarelli, S.

2018-03-01

Solid krypton (Kr) undergoes a pressure-induced martensitic phase transition from a face-centered cubic (fcc) to a hexagonal close-packed (hcp) structure. These two phases coexist in a very wide pressure domain inducing important modifications of the bulk properties of the resulting mixed phase system. Here, we report a detailed in situ x-ray diffraction and absorption study of the influence of the fcc-hcp phase transition on the compression behavior of solid krypton in an extended pressure domain up to 140 GPa. The onset of the hcp-fcc transformation was observed in this study at around 2.7 GPa and the coexistence of these two phases up to 140 GPa, the maximum investigated pressure. The appearance of the hcp phase is also evidenced by the pressure-induced broadening and splitting of the first peak in the XANES spectra. We demonstrate that the transition is driven by a continuous nucleation and intergrowth of nanometric hcp stacking faults that evolve in the fcc phase. These hcp stacking faults are unaffected by high-temperature annealing, suggesting that plastic deformation is not at their origin. The apparent small Gibbs free-energy differences between the two structures that decrease upon compression may explain the nucleation of hcp stacking faults and the large coexistence domain of fcc and hcp krypton. We observe a clear anomaly in the equation of state of the fcc solid at ˜20 GPa when the proportion of the hcp form reaches ˜20 % . We demonstrate that this anomaly is related to the difference in stiffness between the fcc and hcp phases and propose two distinct equation of states for the low and high-pressure regimes.

Temperature Programmed Desorption of Quench-condensed Krypton and Acetone in Air; Selective Concentration of Ultra-trace Gas Components.

Science.gov (United States)

Suzuki, Taku T; Sakaguchi, Isao

2016-01-01

Selective concentration of ultra-trace components in air-like gases has an important application in analyzing volatile organic compounds in the gas. In the present study, we examined quench-condensation of the sample gas on a ZnO substrate below 50 K followed by temperature programmed desorption (TPD) (low temperature TPD) as a selective gas concentration technique. We studied two specific gases in the normal air; krypton as an inert gas and acetone as a reactive gas. We evaluated the relationship between the operating condition of low temperature TPD and the lowest detection limit. In the case of krypton, we observed the selective concentration by exposing at 6 K followed by thermal desorption at about 60 K. On the other hand, no selectivity appeared for acetone although trace acetone was successfully concentrated. This is likely due to the solvent effect by a major component in the air, which is suggested to be water. We suggest that pre-condensation to remove the water component may improve the selectivity in the trace acetone analysis by low temperature TPD.

气相色谱氩、氪、氙、氡分离度初步研究%Resolutions on Mixture of Argon, Krypton, Xenon and Radon by Gas Chromatography

Institute of Scientific and Technical Information of China (English)

刘蜀疆; 陈占营; 常印忠; 王世联; 李奇; 石建芳; 樊元庆; 赵允刚

2012-01-01

核爆炸产生多种稀有气体核素,这些核素可作为核泄露监测对象.气相色谱是组分分离的重要手段,在核爆炸监测取样中有重要应用.本文以5A分子筛作为固定相,高纯氮作为流动相,测量了氩、氪、氙、氡在气相色谱中的分离效果.结果表明,在相同色谱条件下,氩、氪分离度小于氪、氙分离度；在柱流量35.6 mL/min、柱温353 K条件下,气相色谱氩、氪,氪、氙,氙、氡分离度均大于2.25.%Radio-isotopes of noble gas, which are produced during nuclear explosion, can escape into atmosphere easily. These isotopes can be measured as good indicators for nuclear explosion. Noble gas monitoring, including sampling, measurement and analysis, became more and more essential. Gas chromatography is an important technology on noble gas separation during gas sampling. In this paper, while 5A molecular sieve was utilized as column stationary state and high-purity nitrogen as column fluid state, resolutions of argon, krypton, xenon and radon were widely investigated under different chromatograph conditions. As a result, the resolution of krypton and argon is less than the resolution of xenon and krypton; when column flow rate is 35. 6 mL/min and oven temperature is 353 K, all of the resolutions of radon and xenon, xenon and krypton, krypton and argon are more than 2. 25.

Spin asymmetries for elastic scattering in krypton at intermediate energies

International Nuclear Information System (INIS)

Went, M R; McEachran, R P; Lohmann, Birgit; MacGillivray, W R

2002-01-01

Measurements of the spin asymmetry for elastic scattering of spin-polarized electrons from krypton are presented, for incident energies in the range 20-200 eV. The measured spin asymmetries are generally small, and do not exceed 0.25 in magnitude at any energy or angle. The experimental results are compared with calculated values of the Sherman function, obtained by solution of the Dirac-Fock equations. The calculations have been performed with the inclusion of polarization and dynamic distortion potentials, and with the addition of an absorption potential to model inelastic processes. For incident energies of 50, 60 and 65 eV, the calculated values of the Sherman function are shown to be extremely sensitive to the details of the model, with the addition of the absorption potential producing dramatically different results

Concept of transfer functions for a nuclear reactor; Notion de fonction de transfert pour un reacteur nucleaire

Energy Technology Data Exchange (ETDEWEB)

Dalfes, Abdi [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Departement d' Electronique Generale, Service d' Electronique des Reacteurs

1966-07-01

The solution to the correlation equations are expressed in terms of the eigenvalues and Eigen-matrices of the transport operator, for a subcritical zero power reactor. This allows to define, for each point of the reactor and for detectors detecting neutrons of given velocities, correlation and transfer functions driven by the same white-noise source. A precise meaning is also given to the importance operator, which is the adjoin of the transport operator. (author) [French] La solution des equations regissant les matrices de correlation est exprimee en fonction des valeurs et matrices propres de l'operateur de transport pour un reacteur sous-critique et de puissance nulle. Ceci permet de definir, en chaque point du reacteur et pour des detecteurs repondant a des neutrons de vitesse definie, des fonctions de correlation et de transfert dont les entrees sont attaquees par une meme source de bruit blanc. Le role joue par l'operateur importance, adjoint de l'operateur de transport, est aussi precise. (auteur)

Generation of Multicharged Krypton Ions in Nanosecond Laser Ionization of Krypton Beam%纳秒激光电离产生Kr17+的研究

Institute of Scientific and Technical Information of China (English)

罗晓琳; 孔祥蕾; 牛冬梅; 渠洪波; 李海洋

2004-01-01

Up to Kr17+ muhicharged krypton ions have been observed in time-of-flight mass spectrum by a 25 ns Nd-YAG 1. 064 μm laser at laser intensity about 1012 W/cm2. Experimental results indicate that the muhicharged ions appear only when the laser interacts with the middle part of the pulsed beam, and the intensities of the multi charged ions increase dramatically by increasing the backing pressure of Kr gas, which indicates that the clusters in the beam is essential to the production of muhicharged ions. From the experimental results, it is concluded that the cluster is ionized via multiphoton ionization and forms a nanoplasma ball, which can absorb the laser resonantly to further ionize the single charge ion to the high charge state.

Depleted Krypton & Xenon Recovery Solutions & Characteristics in ASU%空分装置提取贫氪氙的几种方法及其特点

Institute of Scientific and Technical Information of China (English)

李美玲; 郑三七; 张建松; 于浩

2016-01-01

随着氪氙气体在国民经济中的地位日趋升高，空分行业利用空分装置副产品提取氪氙的工艺研究也大力开展，针对空分工艺的特点进行研究和模算，得出了几种切实可行的提取贫氪氙的方法，氪氙提取率高，设备结构紧凑，流程简单，可操作性强。给用户提供更多的选择。%With the rising status of krypton and xenon gases in national economy, researches on krypton and xenon recovery process utilizing ASU have been developed rapidly in ASU industry. Based on the ASU process characteristics, studies and simulation calculations are made, therefore, several practical and feasible recovery solutions are put forward. With the characteristics of high krypton & xenon recovery rate, compact structure, simple process and strong operability, we could provide our customers with more options.

Study of the experimental data of multifragmentation of gold and krypton nuclei on interactions with photoemulsion nuclei at high energies

International Nuclear Information System (INIS)

Saleh, Z.A.; Abdel-Hafez, A.

2002-01-01

Results from EMU-01/12 collaboration for the experimental data on multifragmentation of gold residual nuclei created in the interactions with photoemulsion nuclei at the energy of 10.7 GeV/nucleon are presented together with the experimental data on multifragmentation of krypton created on the interactions with photoemulsion nuclei at energy of 0.9 GeV/nucleon. The data are analyzed in the frame of the statistical model of multifragmentation. It is obvious that there are two regimes for nuclear multifragmentation: the former is when less than one-half of nucleons of projectile nucleus are knocked out, the later is when more than one-half of nucleons are knocked out. Residual nuclei with masses close to each other created at different reactions are fragmented practically simultaneously when more than one-half of nucleons of original nuclei are knocked out. These results give an indication that projectiles other than Gold and Krypton may give the same characterization on interaction with emulsion nuclei at high energies

Thermodynamic consistency of vapor pressure and calorimetric data for argon, krypton, and xenon

International Nuclear Information System (INIS)

Schwalbe, L.A.; Crawford, R.K.; Chen, H.H.; Aziz, R.A.

1977-01-01

A new two-parameter vapor pressure equation has been derived which, unlike the Salter equation, is shown to be equally applicable to quantum or classical solids and even liquids. The condensed phase enthalpies and entropies are given directly by the fitted parameters with accuracies comparable to those which have been claimed for existing independent calorimetric measurements. Recent vapor pressure data for the solid and liquid phases of argon, krypton, and xenon are analyzed in this manner, and the results are compared with the available calorimetric data. New values for the cohesive energy at T=0 are also derived for these substances

The sputtering of the deformed gold under irradiation with krypton swift heavy ions

International Nuclear Information System (INIS)

Didyk, A.Yu.; Semina, V.K.; Hofman, A.

2002-01-01

The results about sputtering yield of gold irradiated by 86 Kr ions with high inelastic energy losses up to a fluence of 10 14 ion/cm 2 are presented. It was shown that the sputtering (evaporation) yield strongly depends on the initial defect concentration in gold. The sputtering yield begins to grow very strongly with the increasing of damage created by heavy ion elastic and inelastic energy losses. The temperature on the surface in the area around krypton ion trajectory is much higher than the melting and evaporation temperatures for gold as follows from calculations with the various expressions and models

Cyclotron production of krypton-77 for regional cerebral blood flow measurement

International Nuclear Information System (INIS)

Houdayer, A.J.; Meyer, E.; Yamamoto, Y.L.

1977-01-01

Krypton-77 has favourable decay characteristics for use in studies of regional cerebral blood flow, and the gas may be administered by inhalation. A description is given of the preparation and separation of radioactive sources of 77 Kr gas of strength between 1 and 5 mCi. The sources were produced via the reaction 79 Br(p,3n) 77 Kr induced by 30 MeV protons in targets of NaBr powder enriched to 99.75% 79 Br. A simple and rapid separation of the other contaminants produced in the target was achieved by means of cold traps. The fresh product showed no gamma ray spectra other than those of 77 Kr and 79 Kr, and only traces of 79 Kr were present. (U.K.)

The International Reactor Dosimetry File (IRDF-85)

International Nuclear Information System (INIS)

Cullen, D.E.; McLaughlin, P.K.

1985-04-01

This document describes the contents of the second version of the International Reactor Dosimetry File (IRDF-85), distributed by the Nuclear Data Section of the International Atomic Energy Agency. This library superseded IRDF-82. (author)

Destruction of fast H(2S) atoms in collisions with neon, krypton, xenon, and molecular hydrogen

International Nuclear Information System (INIS)

Roussel, F.; Pradel, P.; Spiess, G.

1977-01-01

Measurements are reported for the total quenching of metastable hydrogen atoms by neon, krypton, xenon, and molecular hydrogen, in the energy range 0.052--3 keV. The cross sections are found to be on the order of 5 x 10 -15 cm 2 at the lowest energies, and decrease to approximately 2 x 10 -15 cm 2 at the highest energies. The data at low energy are analyzed using a simple theoretical model

Analysis and Improvement of Liquid Level Fluctuation in Condenser of Krypton-Xenon Enriched Tower%氪氙富集塔冷凝器液位波动原因分析与改进

Institute of Scientific and Technical Information of China (English)

韩正祥; 赵刘强; 吴冰; 凌晨

2017-01-01

The stability of krypton-xenon enrichment tower in krypton-xenon refining process directly determines the yield and yield of the product.In this paper, the fluctuation of the condenser liquid level in the rare krypton-xenon enrichment tower is analyzed from the aspects of equipment structure.The cause of the fault is analyzed in detail, and the liquid level fluctuation of the condenser in the enrichment tower is solved by improving the operation and reforming the equipment, so as to achieve the stable operation of the krypton xenon purification device.%氪氙精制流程中氪氙富集塔的稳定运行直接决定着产品的合格率及产量.针对稀有氪氙富集塔出现的冷凝器液位波动现象从设备结构、工艺运行等方面,对故障产生的原因进行了详细分析,并通过改进操作、改造设备解决了富集塔冷凝器液位波动问题,达到了氪氙精制装置稳定运行的目的.

Phase behavior of mixed submonolayer films of krypton and xenon on graphite.

Science.gov (United States)

Patrykiejew, A; Sokołowski, S

2012-04-14

Using the results of extensive Monte Carlo simulations in the canonical and grand canonical ensembles, we discuss the phase behavior of mixed submonolayer films of krypton and xenon adsorbed on the graphite basal plane. The calculations have been performed using two- and three-dimensional models of the systems studied. It has been demonstrated that out-of-plane motion does not affect the properties of the films as long as the total density is well below the monolayer completion and at moderate temperatures. For the total densities close to the monolayer completion, the promotion of particles to the second layer considerably affects the film properties. Our results are in a reasonable agreement with the available experimental data. The melting point of submonolayer films has been shown to exhibit non-monotonous changes with the film composition, and reaches minimum for the xenon concentration of about 50%. At the temperatures below the melting point, the structure of solid phases depends upon the film composition and the temperature; one can also distinguish commensurate and incommensurate phases. Two-dimensional calculations have demonstrated that for the xenon concentration between about 15% and 65% the adsorbed film exhibits the formation of a superstructure, in which each Xe atom is surrounded by six Kr atoms. This superstructure is stable only at very low temperatures and transforms into the mixed commensurate (√3×√3)R30° phase upon the increase of temperature. Such a superstructure does not appear when a three-dimensional model is used. Grand canonical ensemble calculations allowed us to show that for the xenon concentration of about 3% the phase diagram topology of monolayer films changes from the krypton-like (with incipient triple point) to the xenon-like (with ordinary triple point).

EVALUATION DE L’IMPACT ENVIRONNEMENTAL : Evaluation des potentialités de transfert de l’ADN des plantes transgéniques vers les bactéries du sol

Directory of Open Access Journals (Sweden)

Simonet Pascal

2000-07-01

Full Text Available Les bactéries se caractérisent par leurs stratégies évolutives multiples incluant mutations ponctuelles, remaniements endogènes par déplacements de séquences d’insertion ou de transposons, délétions ou amplifications de larges régions d’ADN et acquisition de nouveaux gènes par transfert horizontal d’informations génétiques. Les récentes et toutes premières analyses conduites sur les données des quelques génomes bactériens totalement séquencés indiquent le rôle tout à fait fondamental qu’ont pu jouer les transferts latéraux de gènes dans l’évolution bactérienne [1-3]. Nombre de travaux sont aujourd’hui conduits afin d’élucider le rôle des trois mécanismes de transfert (conjugaison, transformation et transduction dans l’évolution et l’adaptation des bactéries aux conditions changeantes de leur environnement. En particulier, l’accroissement inquiétant de la proportion de germes résistants aux antibiotiques serait le fait de la dispersion de plasmides porteurs des gènes de résistance parmi la microflore pathogène ? Dans ces cisconstances, la question de savoir si les plantes transgéniques, très souvent pourvues de tels gènes, pourraient constituer un facteur aggravant la dissémination d’éléments menaçant potentiellement la santé humaine est donc totalement justifiée. Tout au long de l’évolution, la nature a cependant établi un certain nombre de filtres moléculaires afin de limiter les flux de gènes, notamment entre organismes phylétiquement très éloignés. La caractéristique des plantes transgéniques tient à ce que certains des gènes des transgènes, et en particulier ceux conférant la résistance aux antibiotiques, ont une origine procaryotique susceptible de leur permettre de contourner les barrières moléculaires. Cependant, d’autres facteurs environnementaux, biotiques et abiotiques vont intervenir pour favoriser ou au contraire limiter les échanges de g

The determination of surface of powders by BET method using nitrogen and krypton with computer calculation of the results

International Nuclear Information System (INIS)

Dembinski, W.; Zlotowski, T.

1973-01-01

A computer program written in FORTRAN language for calculations of final results of specific surface analysis based on BET theory has been described. Two gases - nitrogen and krypton were used. A technical description of measuring apparaturs is presented as well as theoretical basis of the calculations together with statistical analysis of the results for uranium compounds powders. (author)

Microbiome variation in corals with distinct depth distribution ranges across a shallow-mesophotic gradient (15-85 m)

Science.gov (United States)

Glasl, Bettina; Bongaerts, Pim; Elisabeth, Nathalie H.; Hoegh-Guldberg, Ove; Herndl, Gerhard J.; Frade, Pedro R.

2017-06-01

Mesophotic coral ecosystems (MCEs) are generally poorly studied, and our knowledge of lower MCEs (below 60 m depth) is largely limited to visual surveys. Here, we provide a first detailed assessment of the prokaryotic community associated with scleractinian corals over a depth gradient to the lower mesophotic realm (15-85 m). Specimens of three Caribbean coral species exhibiting differences in their depth distribution ranges ( Agaricia grahamae, Madracis pharensis and Stephanocoenia intersepta) were collected with a manned submersible on the island of Curaçao, and their prokaryotic communities assessed using 16S rRNA gene sequencing analysis. Corals with narrower depth distribution ranges (depth-specialists) were associated with a stable prokaryotic community, whereas corals with a broader niche range (depth-generalists) revealed a higher variability in their prokaryotic community. The observed depth effects match previously described patterns in Symbiodinium depth zonation. This highlights the contribution of structured microbial communities over depth to the coral's ability to colonize a broader depth range.

High resolution krypton M/sub 4,5/ x-ray emission spectra

International Nuclear Information System (INIS)

Perera, R.C.C.; Hettrick, M.C.; Lindle, D.W.

1987-10-01

High resolution M/sub 4,5/ (3d → 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/ΔE, is about 300 in this energy range (∼80 eV). Three dipole-allowed 3d → 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr 2+ , and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab

Study of Krypton-Silver, Krypton-gold, Krypton-thorium interactions at 27 and 43 MeV/n in terms of global variables

International Nuclear Information System (INIS)

Lemiere, J.

1992-07-01

The determination of desexcitation mechanism of hot and compressed nuclear systems formed after heavy ions collisions at intermediate energies asks for and exclusive and complete detection of the products of the reaction and so the use of multidetectors with large angular coverage. In this work, we study fragment production (Z>8) in nuclear collisions of krypton projectiles accelerated at 27 MeV/uma and 43 MeV/uma with silver, gold and thorium target with the help of the measurements provided by two gaseous multidetectors DELF and XYZT at GANIL. We observed events with a multiplicity of fragments up to 5 and 6 at 27 and 43 MeV/uma respectively (whatever the nature of target). We restricted our study to central collisions with at least 3 heavy fragments detected by separating peripheral collisions which had kept the memory of entrance channel. The recoil velocity of fragments for central events indicates high excitation energy which is comparable to total binding energy of the system. In order to normalize and compact the information which represent the velocities and charges of the 3, 4 or 5 detected fragments, we used several global variables as flow angle and isotropy ratio. We tested if these variables were no too modified by the limitations of the experimental setup by using Monte Carlo simulations. We observed some important differences between the systems we used: first, more events with large flow angle or isotropy ratio for the gold target than for the silver one, second relatively more events with large isotropy ratio for 43 MeV/uma than for 27 MeV/uma. Events with small flow angle has a weak memory of the entrance channel, but the events with large flow angle do not, this indicates the flow angle to be an estimation of impact parameter. The difference between gold and silver target has been assumed to be due to the difference of overlap cross section of the Kr-Au and Kr-Ag systems

DLTS spectra of silicon diodes with p+-n-junction irradiated with high energy krypton ions

Directory of Open Access Journals (Sweden)

Nikolai A. Poklonski

2016-06-01

Full Text Available p+-n-Diodes have been studied. The diodes were manufactured on wafers (thickness 460 μm, (111 plane of uniformly phosphorus doped float-zone-grown single-crystal silicon. The resistivity of silicon was 90 Ω cm and the phosphorus concentration was 5×1013 cm−3. The diodes were irradiated with 250 MeV krypton ions. The irradiation fluence was 108 cm−2. Deep-level transient spectroscopy (DLTS was used to examine the defects induced by high energy krypton ion implantation. The DLTS spectra were recorded at a frequency of 1 MHz in the 78–290 K temperature range. The capacity-voltage characteristics have been measured at a reverse bias voltage from 0 to −19 V at a frequency of 1 MHz. We show that the main irradiation-induced defects are A-centers and divacancies. The behavior of DLTS spectra in the 150–260 K temperature range depends essentially on the emission voltage Ue. The variation of Ue allows us to separate the contributions of different defects into the DLTS spectrum in the 150–260 K temperature range. We show that, in addition to A-centers and divacancies, irradiation produces multivacancy complexes with the energy level Et = Ec−(0.5±0.02 eV and an electron capture cross section of ~4×10–13 cm2.

Krypton yellow laser for the treatment of macular hole in high myopia without retinal detachment.

Science.gov (United States)

Cai, Ji-Ping; Cheng, Jin-Wei; Ma, Xiao-Ye; Li, Yu-Zhen; Li, You; Wei, Rui-Li

2008-12-01

To evaluate the prophylactic effect of krypton yellow laser for the treatment of macular holes in high myopic eyes in order to reduce the risk of retinal detachment. Twenty-seven eyes of 27 patients with high myopia and macular holes were randomly assigned to two groups. Fifteen patients (group A, 15 eyes) were subject to laser photocoagulation around the hole margin along with an oral placebo (vitamin B1), while 12 patients (group B, 12 eyes) were only given the oral placebo (vitamin B1). The incident rate of retinal detachment due to macular hole and the mean best-corrected visual acuity of the two groups before and after treatment were measured. The data were statistically tested by X2 test and Student's t test. The incident rates of retina1 detachment in group A and group B were 20%(3/15) and 58.3%(7/12), respectively (X2=4.201, P0.05). The mean BCVA of group B on the initial examination was 24/200, while the mean BCVA at the final follow-up was 30/200 (P>0.05). No significant difference in initial visual acuity (P>0.05) or final visual acuity (P>0.05) was found between the two groups. Krypton yellow laser photocoagulation could reduce the incidence of retinal detachment due to a macular hole in high myopia with acceptable functional results in this study.

Effective and accurate approach for modeling of commensurate–incommensurate transition in krypton monolayer on graphite

International Nuclear Information System (INIS)

Ustinov, E. A.

2014-01-01

Commensurate–incommensurate (C-IC) transition of krypton molecular layer on graphite received much attention in recent decades in theoretical and experimental researches. However, there still exists a possibility of generalization of the phenomenon from thermodynamic viewpoint on the basis of accurate molecular simulation. Recently, a new technique was developed for analysis of two-dimensional (2D) phase transitions in systems involving a crystalline phase, which is based on accounting for the effect of temperature and the chemical potential on the lattice constant of the 2D layer using the Gibbs–Duhem equation [E. A. Ustinov, J. Chem. Phys. 140, 074706 (2014)]. The technique has allowed for determination of phase diagrams of 2D argon layers on the uniform surface and in slit pores. This paper extends the developed methodology on systems accounting for the periodic modulation of the substrate potential. The main advantage of the developed approach is that it provides highly accurate evaluation of the chemical potential of crystalline layers, which allows reliable determination of temperature and other parameters of various 2D phase transitions. Applicability of the methodology is demonstrated on the krypton–graphite system. Analysis of phase diagram of the krypton molecular layer, thermodynamic functions of coexisting phases, and a method of prediction of adsorption isotherms is considered accounting for a compression of the graphite due to the krypton–carbon interaction. The temperature and heat of C-IC transition has been reliably determined for the gas–solid and solid–solid system

Comparison of iodine, krypton, and xenon retention efficiencies for various silver loaded adsorption media

International Nuclear Information System (INIS)

Huchton, R.L.; Tkachyk, J.W.; Taylor, J.T.; Motes, B.G.

1985-03-01

A comparison was made among various silver impregnated adsorption media to determine their iodine, krypton, and xenon retention efficiencies. The program consisted of three components. First, laboratory measurements of the noble gas retention efficiencies of commercially available adsorption media were determined as a function of relative humidity, sample duration, test cartridge geometry, and ambient air purge. Second, a literature survey was performed to evaluate the iodine species retention efficiencies of the selected media. Third, data associated with a media previously proposed for an emergency response air sampler were incorporated to enlarge the data base. 41 refs., 6 figs., 14 tabs

Use of a krypton isotope for rapid ion changeover at the Lawrence Berkeley Laboratory 88-inch cyclotron

Science.gov (United States)

Soli, George A.; Nichols, Donald K.

1989-01-01

An isotope of krypton, Kr86, has been combined with a mix of Ar, Ne, and N ions at the electron cyclotron resonance (ECR) source, at the Lawrence Berkeley Laboratory cyclotron, to provide rapid ion changeover in Single Event Phenomena (SEP) testing. The new technique has been proved out successfully by a recent Jet Propulsion Laboratory (JPL) test in which it was found that there was no measurable contamination from other isotopes.

Krypton Derivatization of an O2 -Tolerant Membrane-Bound [NiFe] Hydrogenase Reveals a Hydrophobic Tunnel Network for Gas Transport.

Science.gov (United States)

Kalms, Jacqueline; Schmidt, Andrea; Frielingsdorf, Stefan; van der Linden, Peter; von Stetten, David; Lenz, Oliver; Carpentier, Philippe; Scheerer, Patrick

2016-04-25

[NiFe] hydrogenases are metalloenzymes catalyzing the reversible heterolytic cleavage of hydrogen into protons and electrons. Gas tunnels make the deeply buried active site accessible to substrates and inhibitors. Understanding the architecture and function of the tunnels is pivotal to modulating the feature of O2 tolerance in a subgroup of these [NiFe] hydrogenases, as they are interesting for developments in renewable energy technologies. Here we describe the crystal structure of the O2 -tolerant membrane-bound [NiFe] hydrogenase of Ralstonia eutropha (ReMBH), using krypton-pressurized crystals. The positions of the krypton atoms allow a comprehensive description of the tunnel network within the enzyme. A detailed overview of tunnel sizes, lengths, and routes is presented from tunnel calculations. A comparison of the ReMBH tunnel characteristics with crystal structures of other O2 -tolerant and O2 -sensitive [NiFe] hydrogenases revealed considerable differences in tunnel size and quantity between the two groups, which might be related to the striking feature of O2 tolerance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contribution to thermodynamics and kinetics of argon, krypton and xenon at very low temperatures; Contribution a l'etude thermodynamique et cinetique de l'argon, du krypton et du xenon aux tres basses temperatures

Energy Technology Data Exchange (ETDEWEB)

Levenson, L L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

A critical analysis of the main theories of condensation, which are due to Zwanzig, Cabrera, Mc Caroll and Ehrlich, Wanlass, Armand, and Yu and Soo, is made. A condensation coefficient equal to unity is expected from these theories, except Armand and Yu and Soo, when the temperature of the gas impinging on its own solid phase is equal or less than 300 K. Using a resonating quartz microbalance the sensitivity of which is 10{sup -9} g. cm{sup 2} the experimental data agree with these theories when the temperature of the solid is less than 20 K. However the agreement must be interpreted for the more sophisticated theories of Armand and Yu and Soo. Regarding the sublimation of the rare gases one is faced with the theories of Salter, Eyring, Goodman and Armand. Within an order of magnitude the experimental data given here agree with the expected values. Moreover Armand theory is able to give the physical meaning of the observed results for argon sublimation from a krypton or a xenon crystalline substrate: localized modes of surface vibration occur. The relaxation time for the thermalization of the argon deposit is found greater than twelve hours at 25 K. (author) [French] Ce travail inclut l'etude critique des principales theories de la condensation dues a Zwanzig, Cabrera, Mc Caroll et Ehrlich, Wanlass, Armand, et Yu et Soo. Ces theories, sauf les deux dernieres, prevoient un coefficient de condensation egal a 1 lorsque le gaz incident sur son propre solide a une temperature inferieure ou egale a 300 K. Les mesures effectuees a l'aide d'une microbalance a quarz resonnant sensible a 10{sup -9} g. cm{sup 2} ont confirme ces theories dans le cas ou la temperature du solide est inferieure a 20 K. Cet accord doit cependant etre interprete pour les theories plus completes d'Armand d'une part, Yu et Soo d'autre part. Pour la sublimation des gaz rares on se trouve en presence des theories de Salter, Eyring, Goodman et Armand. Leurs previsions sont en accord, a un ordre de

Review of the adsorption of radioactive krypton and xenon on activated charcoal

International Nuclear Information System (INIS)

Underhill, D.W.; Moeller, D.W.

1981-01-01

This report summarizes the results of a critical review of the published literature on the adsorption of radioactive krypton and xenon on activated charcoal. This review, which was supported by the Advisory Committee on Reactor Safeguards, US Nuclear Regulatory Commission, showed that (a) individual charcoals have a wide range of adsoprtion coefficients and therefore the performance of a given bed is heavily dependent on the quality of the charcoal it contains; (b) because of the detrimental effects of mass transfer on noble gas adsorption, consideration should be given to including this factor in developing technical specifications for adsorption beds; and (c) additional research is needed on the determination of the inter-relationship of moisture and temperature and their effects on adsorption bed performance

Heat transfer by gas-liquid mixture in forced turbulent flow with weak vaporization of the liquid phase (1962); Transfert de chaleur par melange de liquide et de gaz en convection forcee turbulente avec faible vaporisation de la phase liquide (1962)

Energy Technology Data Exchange (ETDEWEB)

Huyghe, J; Mondin, G [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1962-07-01

The present study deals with measures of heat transfer and pressure drop in two-phase liquid flow. The stream is of annular dispersed type, obtained by introducing a small quantity of liquid in a gas turbulent flow. The heat transfer experiments are performed without vaporization of the liquid phase. A notable improvement of the heat transfer coefficient of such a stream is observed, compared with a gas-alone or liquid-alone flow. The improvement concerning the gas-alone is of about 20 when it is compared with the same gas Reynolds's number, of about 8 when it is compared with the same total mass flow rate. A hydrodynamic study of the flow pattern lets us know the original structure of the flow, and allows to foresee the experimental results by means of a simplified theory. (authors) [French] II est fait etat de mesures de transfert thermique et de perte de charge dans un ecoulement en double phase gaz-liquide. L'ecoulement est du type annulaire disperse, obtenu par injection d'une faible quantite de liquide dans un ecoulement gazeux en regime turbulent. Les experiences de transfert thermique sont menees sans vaporisation de la phase liquide. On note une amelioration sensible du coefficient de transfert thermique dans un tel ecoulement par rapport a un ecoulement de gaz seul ou de liquide seul. L'augmentation est de l'ordre de 20 par rapport au gaz seul si on opere a meme nombre de REYNOLDS du gaz, de l'ordre de 8 si on opere a meme debit massique total. Une etude hydrodynamique rapide de l'ecoulement permet de connaitre la structure originale de l'ecoulement, puis de prevoir par une theorie simplifiee le phenomene thermique observe. (auteurs)

Charter for the development of the super-ethanol E85 channel in France; Charte pour le developpement de la filiere superethanol E85 en France

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

Signed by more than 25 associations, or enterprises and the Government, this charter underlines eight main points in favor of the super-ethanol E85 development. Then the charter defines the actions plan allowing to assure the success of the launching and the development of the super-ethanol E85 channel: the necessary standards and technic, the diversified and impressive offer of flex-fuel vehicles, the E85 distribution network on the territory, the development of a competitive and sustainable channel of ethanol production, the economic and fiscal conditions allowing the E85 to be competitive facing the fossil fuels and the following of the actions plan. (A.L.B.)

Relativistic configuration interaction treatment of generalized oscillator strength for krypton

International Nuclear Information System (INIS)

Wang Huangchun; Qu Yizhi; Liu Chunhua

2007-01-01

A fully relativistic configuration interaction method is developed to investigate the transition energies and general oscillator strengths of the lower lying states of krypton, for both optically allowed and optically forbidden transitions. The calculated results are in agreement with the recent experimental measurements. The calculated transition energies for the 5s and 5s' transitions are 9.970 and 10.717 eV, which agree with the experimental data of 10.033 and 10.643 eV. The calculated oscillator strengths are 0.211 and 0.170, comparable with the experimental results 0.214(±0.012) and 0.194 (±0.012), respectively. The momentum transfer positions (K 2 in a.u.) of the minimum and maximum GOSs in the 4s 2 4p 6 →4s 2 4p 5 (5s + 5s') transitions are 1.105 and 2.225, comparable with the measurements results 1.24 and 2.97. (authors)

Relativistic Configuration Interaction Treatment of Generalized Oscillator Strength for Krypton

Institute of Scientific and Technical Information of China (English)

WANG Huang-Chun; QU Yi-Zhi; LIU Chun-Hua

2007-01-01

A fully relativistic configuration interaction method is developed to investigate the transition energies and general oscillator strengths of the lower lying states of krypton, for both optically allowed and optically forbidden transitions. The calculated results are in agreement with the recent experimental measurements. The calculated transition energies for the 5s and 5s' transitions are 9.970 and 10.717eV, which agree with the experimental data of 10.033 and 10.643 eV. The calculated oscillator strengths are 0.211 and 0.170, comparable with the experimental results 0.214(±0.012) and 0.194 (±0.012), respectively. The momentum transfer positions ( K2 in a.u.) of the minimum and maximum GOSs in the 4s24p6 → 4s24p5 (5s + 5s') transitions are 1.105 and 2.225, comparable with the measurements results 1.24 and 2.97 [Phys. Rev. A 67 (2003) 062708].

Amorphization, morphological instability and crystallization of krypton ion irradiated germanium

International Nuclear Information System (INIS)

Wang, L.M.; Birtcher, R.C.

1991-01-01

Krypton ion irradiation of crystalline Ge and subsequent thermal annealing were both carried out with in situ transmission electron microscopy observations. The temperature dependence of the amorphization dose, effect of foil thickness, morphological changes during continuous irradiation of the amorphous state as well as the effect of implanted gas have been determined. The dose of 1.5 MeV Kr required for amorphization increases with increasing temperature. At a fixed temperature, the amorphization dose is higher for thicker regions of the specimen. Continuous irradiation of amorphous Ge at room temperature results in a high density of small cavities which grow with increasing dose. Cavities do not coalesce during growth but develop into irregular-shaped holes that eventually transform the amorphous Ge into a sponge-like material. Formation of the spongy structure is independent of Kr implantation. The crystallization temperature and the morphology of recrystallized Ge depend on the Kr + dose. Voids are expelled from recrystallized Ge, while the sponge-like structure is retained after crystallization. (author)

Solution of the transfer functions and the linear networks by an analog computer; Resolution des fonctions de transfert et des reseaux lineaires sur calculateur analogique

Energy Technology Data Exchange (ETDEWEB)

Bras, D

1967-09-27

This study presents five methods used to realize a transfer function on analog computer - method of operational amplifiers - method of successive integrations - method of the auxiliary variable - method of the Horner decomposition - method of the direct analog transposition. The method that seems to us the most interesting, this one of Horner, is exposed with some complements. The last method presents the study of a linear network (mechanical, electronic) by direct analog transposition, without having to calculate its transfer function. Several aspects are studied the economy or the material type, the simpleness of implementing the adaptation of coefficients to the computer, the introduction of initial conditions of input and output functions. Every method presented is discussed in function of these problems. The precision of the result is not studied here, but we can indicate that the methods treated here, do not include approximations other than these ones of the computer elements. [French] Cette etude presente cinq methodes utilisees pour realiser une fonction de transfert quelconque sur calculateur analogique - methode des Amplificateurs operationnels - methode des integrations successives - methode de la variable auxiliaire - methode de la decomposition de Horner - methode de la transposition analogique directe. La methode qui nous semble la plus interessante, celle de Horner, est exposee avec quelques complements. La derniere methode presente l'etude d'un reseau lineaire (mecanique, electronique...) par transposition analogique directe, sans avoir a calculer sa fonction de transfert. Plusieurs aspects sont etudies l'economie ou le type de materiel, la simplicite de mise en oeuvre l'adaptation des coefficients au calculateur, l'introduction des conditions initiales des fonctions d'entree et de sortie. Chaque methode presentee est discutee en fonction de ces problemes. La precision du resultat n'est pas etudiee ici, mais on peut indiquer toutefois que les

Study of krypton laser-induced choroidal neovascularization in a Guinea pig model of high anisometropia.

Science.gov (United States)

Wang, Jianghui; Jiang, Wei; Kang, Zefeng; Liang, Lina; Liu, Xiaoman; Tian, Nannan; Zhang, Qing

2012-06-01

To investigate the association between high anisometropia and the area of choroidal neovascularization (CNV) induced by krypton laser in guinea pigs and better understand the pathogenesis and prevention of myopic CNV. Nine 3-week old male guinea pigs with anisometropia >6.00D were randomly assigned to three groups according to examination date after laser photocoagulation (7d, 14d and 28d). All animals underwent refraction. The eye with higher myopia was used as the experimental eye, and the other as the control eye. All eyes received repeated multi-wavelength krypton laser photocoagulation treatments (wavelength: 532nm; laser power: 400mW; spot diameter: 50μm; exposure time: 0.1s). Fundus photography and indocyanine green angiography (ICGA) were performed. Afterwards, the animals were sacrificed immediately, and the eyes were enucleated and processed for histopathologic examination and flat mounts. CNV appeared at 7d after laser treatment. The area of CNV peaked at 14d, and decrease in area and the presence of scarring was noted at 28 d. CNV was present in 66.7% of eyes by ICGA at 14 d. CNV could be observed under light microscopy at all three time points. At 14d, flat mount showed the neovascular plexus around the lesion. Semi-quantitative analysis revealed that the area of CNV in treated eyes was greater than that of control eyes. Since the mechanism of CNV in this study resembles that of CNV in pathological myopia, this model can be used to investigate the etiology, pathogenesis and treatment of CNV in pathological myopia.

Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

Energy Technology Data Exchange (ETDEWEB)

Chu, X. X.; Zhang, D. X.; Qian, Y.; Liu, W. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800 (China); Zhang, M. M.; Xu, D. [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 (China)

2014-01-29

In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H{sub 2} from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H{sub 2} in helium recycle gas are less than 1 ppb.

2s 2p 3P10 → 2s21S0 intercombination line in beryllium-like krypton, molybdenum and tungsten

International Nuclear Information System (INIS)

Glass, R.

1979-01-01

Transition probabilities are evaluated for the 2s 2p 3 P 1 0 → 2s 2 1 S 0 transition in beryllium-like ions for krypton, molybdenum and tungsten, using configuration-interaction wavefunctions. The importance of the 2s 3p 1 P 1 0 configuration is considered

Pulmonary dynamics and functional imaging with krypton-81m as related to generator delivery characteristics

International Nuclear Information System (INIS)

Kaplan, E.

1985-01-01

Krypton-81m supplied from a generator by continuous elution with air is used with a gamma-camera computer system to produce a sequence of images from multiple breaths, which reconstructed the time-activity images of the breathing human lung. Functional images are produced by subsequent derivation to show specific variables of the dynamic sequences. The dynamic, quantitative, and regional aspects of the respiratory cycle are thus made available in a single study. The need for the delivery of a constant ratio of /sub 81m/Kr to air is required to accurately produce these various studies

Adsorption properties of a molecular 5 A sieve for 85Kr

International Nuclear Information System (INIS)

Wardaszko, T.; Nidecka, J.

1978-01-01

The enrichment processes which are necessary at low-level 85 Kr determinations in the atmospheric air require the knowledge of adsorption properties of appropriate sorbing agents, such as a molecular 5A sieve. Following low-temperature adsorption, under specified conditions, of known amounts of 85 Kr diluted in the air, desorption was carried out and then the 85 Kr content in the temperature fraction as well as their total volume were determined. Distribution curves for the above quantities in fractions are presented. (author)

The absolute photoionization cross sections of helium, neon, argon and krypton in the extreme vacuum ultraviolet region of the spectrum

International Nuclear Information System (INIS)

West, J.B.; Marr, G.V.

1976-01-01

An experiment has been set up at the Daresbury Synchrotron Radiation Facility to make absolute absorption cross section measurements over a wide range of photon energies. New data are reported for helium, neon, argon and krypton over the range 340 to 40 A which are believed to be reliable to +- 5%. A critical evaluation of published cross section data has been carried out to produce best value data from the ionization thresholds throughout the vacuum ultraviolet and x-ray region. Agreement with theoretical calculations on helium is demonstrated to be within +- 2 to 3% from threshold down to the double ionization threshold at 79 eV. Comparison with recent calculations of photoionization cross sections has shown that the effect of electron correlations is significant for the heavier inert gases. Contrary to previous claims, the position of the M shell maximum in krypton is located at 184 +- 10 eV in good agreement with r.p.a.e. calculations. Oscillator strength sum rules have been examined and their moments calculated. Discrepancies developing towards the heavier inert gases suggests a decrease in polarizabilities and other atomic factors from those predicted by Hartree-Fock calculations. (author)

Lightning and 85-GHz MCSs in the Global Tropics

Science.gov (United States)

Toracinta, E. Richard; Zipser, E. J.

1999-01-01

Numerous observations of tropical convection show that tropical continental mesoscale convective systems (MCSs) are much more prolific lightning producers than their oceanic counterparts. Satellite-based climatologies using 85-GHz passive microwave ice-scattering signatures from the Special Sensor Microwave/Imager (SSM/I) indicate that MCSs of various size and intensity are found throughout the global tropics. In contrast, global lightning distributions show a strong land bias with an order of magnitude difference between land and ocean lightning. This is somewhat puzzling, since 85-GHz ice-scattering and the charge separation processes that lead to lightning are both thought to depend upon the existence of large graupel particles. The fact that low 85-GHz brightness temperatures are observed in tropical oceanic MCSs containing virtually no lightning leads to the postulate that tropical oceanic and tropical continental MCSs have fundamentally different hydrometeor profiles through the mixed phase region of the cloud (0 C Lightning Imaging Sensor (LIS), and the first space-borne radar, facilitates high-resolution case studies of MCS structure throughout the global tropics. An important precursor, however, is to better understand the distribution of MCSs and lightning in the tropics. With that objective in mind, this research undertakes a systematic comparison of 85-GHz-defined MCSs and lightning over the global tropics for a full year, as an initial step toward quantifying differences between land and ocean convective systems.

Solvation of fluoroform and fluoroform-dimethylether dimer in liquid krypton: a theoretical cryospectroscopic study.

Science.gov (United States)

Kohls, Emilija; Mishev, Anastas; Pejov, Ljupčo

2013-08-07

fluoroform monomer, according to experiment, results in small C-H stretching frequency red shift (~-2 cm(-1)), while our approach predicts a blue shift of about 10 cm(-1). By a detailed analysis of the anharmonic C-H stretching frequency dependence on the position of the nearest solvent krypton atom and also by analyzing the vibrational Stark effect induced by the local fluctuating field component parallel to the C-H axis, we have derived several conclusions related to these observations. The frequency vs. C···Kr distance dependence shows appreciable fluctuations and even changes in sign at R values close to the maximum of the C···Kr radial distribution function, so that most of the first-shell Kr atoms are located at positions at which the CH frequency shifts acquire either small negative or small positive values. It so happens, therefore, that even the actual sign of the frequency shift is strongly dependent on the correct description of the first solvation shell around CF3H by the Monte Carlo method, much more than the other in-liquid properties calculated by similar approaches.

Large area electron beam pumped krypton fluoride laser amplifier

International Nuclear Information System (INIS)

Sethian, J.D.; Obenschain, S.P.; Gerber, K.A.; Pawley, C.J.; Serlin, V.; Sullivan, C.A.; Webster, W.; Deniz, A.V.; Lehecka, T.; McGeoch, M.W.; Altes, R.A.; Corcoran, P.A.; Smith, I.D.; Barr, O.C.

1997-01-01

Nike is a recently completed multi-kilojoule krypton fluoride (KrF) laser that has been built to study the physics of direct drive inertial confinement fusion. This paper describes in detail both the pulsed power and optical performance of the largest amplifier in the Nike laser, the 60 cm amplifier. This is a double pass, double sided, electron beam-pumped system that amplifies the laser beam from an input of 50 J to an output of up to 5 kJ. It has an optical aperture of 60 cm x 60 cm and a gain length of 200 cm. The two electron beams are 60 cm high x 200 cm wide, have a voltage of 640 kV, a current of 540 kA, and a flat top power pulse duration of 250 ns. A 2 kG magnetic field is used to guide the beams and prevent self-pinching. Each electron beam is produced by its own Marx/pulse forming line system. The amplifier has been fully integrated into the Nike system and is used on a daily basis for laser-target experiments. copyright 1997 American Institute of Physics

Study of production by cosmic radiation of krypton and xenon in the Saint-Severin meteorite

International Nuclear Information System (INIS)

Lavielle, B.

1987-01-01

The concentrations of Kr and Xe isotropes have been measured by a high sensitivity mass spectrometry technique in 11 samples from a core of the Saint-Severin meteorite. On the basis of our results, we were able to show the role of the shielding depth on the production of Kr and Xe by cosmic ray bombardment. More-over, the experimental results for krypton were compared with calculated values obtained by the Reedy and Arnold model (1972) adapted to cosmic ray irradiation of small spherical objects. Our elaboration of a new systematics of nuclear reactions has lead to a good agreement between experiments and calculations within this model [fr

Estimation of radiation exposure associated with inert gas radionuclides discharged to the environment by the nuclear power industry

International Nuclear Information System (INIS)

Bryant, P.M.; Jones, J.A.

1973-05-01

Several fission product isotopes of krypton and xenon are formed during operation of nuclear power stations, while other radioactive inert gases, notably isotopes of argon and nitrogen, are produced as neutron activation products. With the exception of 85 Kr these radionuclides are short-lived, and the containment and hold-up arrangements in different reactor systems influence the composition of the inert gas mixtures discharged to the environment. Cooling of irradiated fuel before chemical reprocessing reduces very substantially the amounts of the short-lived krypton and xenon isotopes available for discharge at reprocessing plants, but almost all the 85 Kr formed in the fuel is currently discharged to atmosphere from these plants. Estimates are made of the radiation exposure of the public associated with these discharges to atmosphere taking into account the type of radiation emitted, radioactive half-life and the local, regional and world-wide populations concerned. Such estimates are often based on simple models in which activity is assumed to be distributed in a semi-infinite cloud. The model used in this assessment takes into account the finite cloud near the point of its discharge and its behaviour when dispersion in the atmosphere is affected by the presence of buildings. This is particularly important in the case of discharges from those reactors which do not have high stacks. The model also provides in detail for the continued world-wide circulation of the longer-lived 85 Kr. (author)

Diffusive transport of strontium-85 in sand-bentonite mixtures

International Nuclear Information System (INIS)

Gillham, R.W.; Robin, M.J.L.; Dytynyshyn, D.J.

1983-06-01

Diffusion experiments have been used to determine the transport of 85 Sr in sand-bentonite mixtures. The diffusion experiments were performed on one natural soil (Chalk River sand) and on seven mixtures of bentonite and silica sand, containing from 0 percent to 100 percent bentonite. Two non-reactive solutes ( 36 Cl and 3 H) and one reactive solute ( 85 Sr) were used in the study. The experiments with non-reactive solutes yielded estimates of tortuosity factors. Retardation factors were obtained from experimental porosities, experimental bulk densities, and from batch distribution coefficients (Ksub(d)). These Ksub(d) values are a simple way of describing the solute/medium reaction, and are based on the assumption that the cation-exchange reaction may be described by a linear adsorption isotherm passing through the origin. The results demonstrate that, for practical purposes and for our experimental conditions, the use of the distribution coefficient provides a convenient means of calculating the effective diffusion coefficient for 85 Sr. The porosity and bulk density were also found to have a considerable influence on the effective diffusion coefficient, through the retardation factor. Mixtures containing 5-10 percent bentonite were found to be more effective in retarding 85 Sr than either sand alone, or mixtures containing more bentonite. In the soils of higher bentonite content, the effect of increased cation-exchange capacity was balanced by a decreasing ratio of bulk density to porosity

Determination of Non-Maxwellian Electron Energy Distributions in Low-Pressure Plasmas by Using the Optical Emission Spectroscopy and a Collisional-Radiative Model

International Nuclear Information System (INIS)

Zhu Ximing; Pu Yikang

2011-01-01

A Maxwellian electron energy distribution function (EEDF) is often assumed when using the optical emission line-ratio method to determine the electron temperature in low-temperature plasmas. However, in many cases, non-Maxwellian EEDFs can be formed due to the non-local electron heating or the inelastic-collisional energy loss processes. In this work, with a collisional-radiative model, we propose an approach to obtain the non-Maxwellian EEDF with a 'two-temperature structure' from the emission line-ratios of Paschen 2p levels of argon and krypton atoms. For applications of this approach in reactive gas (CF 4 , O 2 , etc) discharges that contain argon and krypton, recommendations of some specific emission line-ratios are provided, according to their sensitivities to the EEDF variation. The kinetic processes of the relevant excited atoms are also discussed in detail. (cai awardee's article)

Topographic distribution of pulmonary ventilation and perfusion in the horse

International Nuclear Information System (INIS)

Amis, T.C.; Pascoe, J.R.; Hornof, W.

1984-01-01

The regional distribution of ventilation to perfusion ratios (VA/Q) in the lungs of 8 healthy standing Thoroughbred geldings (4.4 +/- 1.5 years, 465.7 +/- 46.6 kg) was studied, using steady-state inhalation and IV infusion of the radioactive gas krypton-81m. The VA/Q was uniformly distributed within a vertical lung strip centered over the 9th rib on the right side. Ventilation per unit of alveolar volume (V/VA) assessed from the clearance of inhaled radioactive gas in 5 horses increased from 0.49 +/- 0.13 (arbitrary units) in nondependent lung zones to 1.45 +/- 0.16 in dependent lung zones. Seemingly, a vertical gradient of pulmonary ventilation exists in the horse that is matched by a similar gradient of perfusion

Topographic distribution of pulmonary ventilation and perfusion in the horse

Energy Technology Data Exchange (ETDEWEB)

Amis, T.C.; Pascoe, J.R.; Hornof, W.

1984-08-01

The regional distribution of ventilation to perfusion ratios (VA/Q) in the lungs of 8 healthy standing Thoroughbred geldings (4.4 +/- 1.5 years, 465.7 +/- 46.6 kg) was studied, using steady-state inhalation and IV infusion of the radioactive gas krypton-81m. The VA/Q was uniformly distributed within a vertical lung strip centered over the 9th rib on the right side. Ventilation per unit of alveolar volume (V/VA) assessed from the clearance of inhaled radioactive gas in 5 horses increased from 0.49 +/- 0.13 (arbitrary units) in nondependent lung zones to 1.45 +/- 0.16 in dependent lung zones. Seemingly, a vertical gradient of pulmonary ventilation exists in the horse that is matched by a similar gradient of perfusion.

Quantifying multiscale porosity and fracture aperture distribution in granite cores using computed tomography

Science.gov (United States)

Wenning, Quinn; Madonna, Claudio; Joss, Lisa; Pini, Ronny

2017-04-01

Knowledge of porosity and fracture (aperture) distribution is key towards a sound description of fluid transport in low-permeability rocks. In the context of geothermal energy development, the ability to quantify the transport properties of fractures is needed to in turn quantify the rate of heat transfer, and, accordingly, to optimize the engineering design of the operation. In this context, core-flooding experiments coupled with non-invasive imaging techniques (e.g., X-Ray Computed Tomography - X-Ray CT) represent a powerful tool for making direct observations of these properties under representative geologic conditions. This study focuses on quantifying porosity and fracture aperture distribution in a fractured westerly granite core by using two recently developed experimental protocols. The latter include the use of a highly attenuating gas [Vega et al., 2014] and the application of the so-called missing CT attenuation method [Huo et al., 2016] to produce multidimensional maps of the pore space and of the fractures. Prior to the imaging experiments, the westerly granite core (diameter: 5 cm, length: 10 cm) was thermally shocked to induce micro-fractured pore space; this was followed by the application of the so-called Brazilian method to induce a macroscopic fracture along the length of the core. The sample was then mounted in a high-pressure aluminum core-holder, exposed to a confining pressure and placed inside a medical CT scanner for imaging. An initial compressive pressure cycle was performed to remove weak asperities and reduce the hysteretic behavior of the fracture with respect to effective pressure. The CT scans were acquired at room temperature and 0.5, 5, 7, and 10 MPa effective pressure under loading and unloading conditions. During scanning the pore fluid pressure was undrained and constant, and the confining pressure was regulated at the desired pressure with a high precision pump. Highly transmissible krypton and helium gases were used as

Explosion and detonation of ozone in mixtures with carrier gases employed in nuclear technology

International Nuclear Information System (INIS)

Weh, M.M.L.

1988-09-01

Explosive ozone is known to be formed during low temperature radiolysis of oxygen. Detailed knowledge on the explosion and the detonation of ozone is therefore required for safety considerations of nuclear installations such as proposed for the cryogenic separation of 85 krypton from the head end off gas of a reprocessing plant. The explosion properties of gaseous ozone in mixtures with oxygen, nitrogen, helium, argon, krypton, xenon and difluorodichloromethane were studied by varying the ozone concentration, the initial pressure and the shape of the vessel containing the gas. Detonation velocities were determined for gaseous mixtures of ozone with oxygen, argon, krypton or xenon as functions of the ozone concentration. In addition, the initial pressure was varied for ozone-xenon mixtures. The effect of a packing such as used in the 85 Kr-separation plant 'KRETA' in KfK on ozone-xenon detonation was investigated. In addition, the effect of low amounts of carbon monoxide, methane and nitrogen dioxide on the explosion (O 3 /Ar) and the detonation (O 3 /Xe) of an ozone-noble gas mixture was determined. (orig.) [de

E85 Dispenser Study

Energy Technology Data Exchange (ETDEWEB)

Moriarty, K.; Johnson, C.; Sears, T.; Bergeron, P.

2009-12-01

This study reviews E85 dispensing infrastructure advances and issues and evaluates the geographic concentration of flexible fuel vehicles (FFVs), E85 stations, ethanol production facilities, and E85 suppliers. Costs, space, financial incentives, and barriers to adding E85 fueling equipment at existing stations are also assessed. This study found that E85 is increasingly available in the U.S. in half of the states; however, the other half have minimal or no E85 fueling options. Despite these gains, E85 is only available at 1% of U.S. gasoline stations. Ethanol production reached 9.5 billion gallons in 2008, but less than 1% is consumed as E85. FFVs have not reached a significant concentration in any county, metropolitan area, or state.

Effect of hydration on the organo-noble gas molecule HKrCCH: role of krypton in the stabilization of hydrated HKrCCH complexes.

Science.gov (United States)

Biswas, Biswajit; Singh, Prashant Chandra

2015-11-11

The effect of hydration on the fluorine free organo-noble gas compound HKrCCH and the role of krypton in the stabilization of the hydrated HKrCCH complexes have been investigated using the quantum chemical calculations on the HKrCCH-(H2O)n=1-6 clusters. Structure and energetics calculations show that water stabilizes HKrCCH through the π hydrogen bond in which the OH group of water interacts with the C[triple bond, length as m-dash]C group of HKrCCH. A maximum of four water molecules can directly interact with the C[triple bond, length as m-dash]C of HKrCCH and after that only inter-hydrogen bonding takes place between the water molecules indicating that the primary hydration shell contains four water molecules. Atom in molecule analysis depicts that π hydrogen bonded complexes of the hydrated HKrCCH are cyclic structures in which the OKr interaction cooperates in the formation of strong O-HC[triple bond, length as m-dash]C interaction. Structure, energetics and charge analysis clearly established that krypton plays an important role in the stabilization as well as the formation of the primary hydration shell of hydrated HKrCCH complexes.

Resonantly-enhanced, four-photon ionization of krypton at laser intensities exceeding 1013 W/cm2

International Nuclear Information System (INIS)

Perry, M.D.; Landen, O.L.; Campbell, E.M.

1987-12-01

The yield of singly- and multiply- charged ions of krypton and xenon is presented as a function of laser intensity and frequency. The measurements were performed using the second harmonic output of a well-characterized, tunable picosecond dye laser in the range 285 to 310 nm at laser intensities from 1 x 10 12 to 10 14 W/cm 2 . Enhancement of the Kr + yield by two orders of magnitude by three-photon resonant, four-photon ionization is observed in the vicinity of the 4d'[5/2] 3 and the 4d[3/2] 1 intermediate states. A model incorporating line shifts and widths scaling linearly with intensity is in good agreement with the experimental results

Heat transfer with organic fluids; Transferts de chaleur par liquides organiques

Energy Technology Data Exchange (ETDEWEB)

Lanza, F [Association Euratom-CEA, Centre d' Etudes de Grenoble, 38 (France). Dept. de Recherches sur la Fusion Controlee; Ricque, R; Villeneuve, J P [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1964-07-01

Using a test channel with a circular cross-section of 12 mm internal diameter the following heat transfer correlation, valid to about {+-} 6 p. 100, was determined for the terphenyls OMP and OM2 with 0, 10, 20 or 30 p. 100 of high polymers: Nu{sub b} = 0.00835 Re{sub b}{sup 0.9} Pr{sub L}{sup 0.4}. This correlation was established with fluxes ranging from 50 to 100 W/cm{sup 2}, temperatures from 290 to 420 C and Reynolds number from 30 000 to 350 000. 8 long-term tests were carried out (250 to 1000 hours continuous running) to determine how deposition on the heating surfaces affects the exchange coefficient. The loops is made of stainless steel except for one part in soft steel. No deposits are observed even if the terphenyl contains 30 ppm of chlorure, while on the other hand deposition is appreciable when heavy substances containing combined oxygen are added. (authors) [French] On a determine sur un canal d'essai de section circulaire de 12 mm de diametre interieur, la correlation de transfert de chaleur suivante valable a {+-} 6 p.100 pres pour les terphenyles OMP et OM2 avec 0, 10, 20 ou 30 p. 100 de haute polymeres Nu{sub b} = 0,00835 Re{sub b}{sup 0.9} Pr{sub L}{sup 0.4}. Cette correlation a ete etablie dans une gamme de flux de 50 a 100 W/cm{sup 2}, de temperature de 290 a 420 C, de Reynolds de 30 000 a 350 000. On a effectue 8 essais de longue duree (250 a 1 000 heures en regime continu) pour determiner l'effet sur le coefficient d'echange de l'encrassement des surfaces chauffantes. La boucle est en acier inoxydable sauf une partie en acier doux; on n'observe aucun encrassement meme si le terphenyle contient 30 ppm de chlore; par contre l'encrassement est sensible quand on ajoute des produits lourds contenant de l'oxygene combine. (auteurs)

Method of separating radioactive krypton gas

International Nuclear Information System (INIS)

Kimura, Shigeru; Awada, Yoshihisa.

1975-01-01

Object: To effectively and safely separate and recover Kr-85, which requires a long storage period for attenuating radioactivity, from a mixture gas consisting of Kr-85 and Xe by a liquefaction distillation method. Structure: A mixture gas consisting of Kr and Xe is subjected to heat exchange in a cooler with Freon gas from a plurality of distillation towers for its temperature reduction from normal temperature to a lower temperature, and then it is supplied to a distillation tower. The distillation tower is held at a pressure above 15 ata, preferably around 20 ata, and a condenser provided at the top of the distillation tower is furnished with Freon as cooling medium. The rare mixture gas is distilled by liquefaction within a distillation tower, and Kr-85 is obtained from a top duct while obtaining Xe from a bottom duct. Xe after separation by liquefaction is returned to a rare mixture gas supply inlet of a liquefaction distillation means for repeated refinement in the distillation tower. (Kamimura, M.)

Étude théorique et expérimentale du transfert du dioctyl phtalate à partir d'un disque de PVC plastifié plongé dans une huile comestible

Science.gov (United States)

Djilani, S.-E.; Toubal, A. A.; Messadi, D.

1998-10-01

When polymer and liquid are contacted with each other, as in packaging, some mass exchanges may occur, which constitute a major drawback when the liquid is a foodstuff or blood. However, these mass transfers in the polymers can appear as very interesting from the industrial point of view, if one is able to use and control them. It is then necessary to have a good knowledge of these transfer processes which are controlled by diffusion. Dioctyl phthalate (DOP) migration into an edible oil was studied under worst conditions: high plasticization level (50% by weight) and temperature(30 circC). The quantitative analysis of DOP in a such complex liquid medium and in the PVC itself was made easy by the use of the radioactive tracer technique. A simplified mathematical model, obtained by neglecting the oil transport in the PVC, was evaluated. This model based on the research of a finite differences explicit solution allows to reproduce for the DOP, the concentration profiles in the polymer and the kinetics of transfer in the oil, with a P-value ≥ 0.001. La mise en contact polymère-liquide se traduit généralement par des échanges de matière entre les 2 milieux considérés, ce qui constitue un inconvénient majeur lorsque le liquide est un aliment ou le sang. Cependant, ces transferts de matière dans les polymères peuvent apparaître comme très intéressants sur le plan industriel, si l'on est capable de les utiliser et de les contrôler. Il est donc nécessaire d'avoir une bonne connaissance de ces processus de transfert qui sont contrôlés par diffusion. Nous avons étudié la migration du dioctyl phtalate (DOP) dans une huile comestible en nous plaçant dans les conditions les plus défavorables: taux de plastification (50% en poids) et température (30°C) élevés. L'analyse quantitative du DOP dans un milieu liquide aussi complexe et dans le PVC lui- même a été facilitée par l'utilisation de la technique des traceurs radioactifs. Un modèle math

A High-Energy Good-Beam-Quality Krypton-Lamp-Pumped Nd:YAG Solid-State Laser with One Pump Cavity

Institute of Scientific and Technical Information of China (English)

LIU Xue-Sheng; WANG Zhi-Yong; YAN Xin; CAO Ying-Hua

2008-01-01

We investigate a high-energy good-beam-quality krypton-lamp-pumped pulsed Nd:YAG solid-state laser with one pump cavity.The symmetrical resonator laser is developed and is rated at 80 J with beam parameter product 12mm mrad.The total system electro-optics efficiency of the lamp-pumped YAG laser is as high as 3.3% and the stability of output energy is ±2% with pulse width tunable between 0.1 ms and 10ms.The experimental results are consistent with the theoretical analysis and simulation.

Mixture-fraction imaging at 1  kHz using femtosecond laser-induced fluorescence of krypton.

Science.gov (United States)

Richardson, Daniel R; Jiang, Naibo; Stauffer, Hans U; Kearney, Sean P; Roy, Sukesh; Gord, James R

2017-09-01

Femtosecond, two-photon-absorption laser-induced-fluorescence (TALIF) imaging measurements of krypton (Kr) are demonstrated to study mixing in gaseous flows. A measurement approach is presented in which observed Kr TALIF signals are 7 times stronger than the current state-of-the-art methodology. Fluorescence emission is compared for different gas pressures and excitation wavelengths, and the strongest fluorescence signals were observed when the excitation wavelength was tuned to 212.56 nm. Using this optimized excitation scheme, 1-kHz, single-laser-shot visualizations of unsteady flows and two-dimensional measurements of mixture fraction and scalar dissipation rate of a Kr-seeded jet are demonstrated.

Femtosecond two-photon laser-induced fluorescence of krypton for high-speed flow imaging.

Science.gov (United States)

Wang, Yejun; Capps, Cade; Kulatilaka, Waruna D

2017-02-15

Ultrashort-pulse (femtosecond-duration) two-photon laser-induced fluorescence (fs-TPLIF) of an inert gas tracer krypton (Kr) is investigated. A detailed spectroscopic study of fluorescence channels followed by the 5p'←←4p excitation of Kr at 204.1 nm is reported. The experimental line positions in the 750-840 nm emission region agree well with the NIST Atomic Spectra Database. The present work provides an accurate listing of relative line strengths in this spectral region. In the range of laser pulse energies investigated, a quadratic dependence was observed between the Kr-TPLIF signal and the laser pulse energy. The single-laser-shot 2D TPLIF images recorded in an unsteady jet demonstrate the potential of using fs excitation at 204.1 nm for mixing and flow diagnostic studies using Kr as an inert gas tracer.

Device for solidification of gaseous wastes

International Nuclear Information System (INIS)

Shimada, Masayuki; Kamei, Hisashi.

1979-01-01

Purpose: To provide the subject device wherein gaseous wastes such as krypton 85 and the like are ionized and accelerated to be injected into solid targets and stored therein, thereby removing the redischarge of gas and making it possible to treat a large quantity of said gas. Constitution: Krypton gas is ionized and accelerated to high energy by an accelerator, and then introduced into an ion injection chamber. In the ion injection chamber a band-shaped target is delivered from a first take-up roll, and krypton ions are injected to said target. Thereafter, other band-shaped target delivered from a second take-up roll is brought into contact with the target in which krypton ions have been injected, and both targets are taken up together while compressing these targets. In this way, even when injected energy is small, the injected gas is not redischarged and can be continuously treated. (Kamimura, M.)

Clinical analysis of PASCAL laser and Krypton ion laser treatment of diabetic retinopathy%PASCAL激光与氪离子激光治疗糖尿病视网膜病变观察分析

Institute of Scientific and Technical Information of China (English)

董如娇; 陈芳; 李冬育; 赵霞; 董明霞

2014-01-01

Objective To evaluate the clinical efficacy difference of PASCAL laser and krypton ion laser treatment of diabetic retinopathy.Methods From June 2010 to June 2012 in The Eye hospital of Tangshan,200 cases (378 eyes) of pre-diabetic proliferative retinopathy and 200 cases (296 eyes) of proliferative diabetic retinopathy were randomly divided into PASCAL laser treatment groups and krypton ion laser treatment group.FFA,vision correction,and comfort questionnaire were re-examined three months after treatment.Results There were similar efficacy on promote avascular area subsided in patients with pre-proliferative diabetic retinopathy both using PASCAL laser and krypton ion laser treatment,the difference was not statistically significant.However,visual impairment was significantly less by PASCAL laser than krypton ion laser treatment (x2 27.562a,P 0.000,P ＜0.01),patients tolerated PASCAL laser significantly better than krypton ion laser (x21.940Ea,P 0.000,P ＜0.01),the above differences were statistically significant.The promoting neovascular regression role of PASCAL laser was weaker than krypton ion laser in the treatment of patients with proliferative diabetic retinopathy (x2-7.562a,P 0.000,P ＜0.01).PASCAL laser on visual impairment was significantly less than krypton ion laser (x2 13.408a,P 0.000,P ＜0.01),patients tolerated PASCAL laser significantly better than krypton ion laser (x2 1.025Ea,P 0.000,P ＜0.01),the above differences were statistically significant.Conclusions PASCAL laser compared with krypton ion laser treatment has some advantages in the early proliferative diabetic retinopathy,while the poor results in the treatment of proliferative diabetic retinopathy.%目的 探讨PASCAL激光与氪离子激光治疗糖尿病视网膜病变的临床疗效的差异.方法 对2010年6月至2012年6月在唐山市眼科医院就诊的200例增殖前期糖尿病视网膜病变患者378只眼;另外选取200例增殖期糖尿病视网膜病变患者296�

Generalized oscillator strengths for 5s, 5s', and 5p excitations of krypton

International Nuclear Information System (INIS)

Li Wenbin; Zhu Linfan; Yuan Zhensheng; Sun Jianmin; Cheng Huadong; Xu Kezun; Zhong Zhiping; Liu Xiaojing

2003-01-01

The absolute generalized oscillator strengths (GOSs) for 5s, 5s ' , 5p [5/2] 3,2 , 5p [3/2] 1,2 , and 5p [1/2] 0 transitions of krypton have been determined in a large K 2 region at a high electron-impact energy of 2500 eV. The positions of the minima and maxima of these GOSs have been determined. The present results show that the angular resolution and pressure effect have great influence on the position and the amplitude of the minimum for the GOS of 5s+5s ' transitions. When these effects are considered, the measured minimum position for the GOS of 5s+5s ' transitions is in excellent agreement with the calculation of Chen and Msezane [J. Phys. B 33, 5397 (2000)

Storage in pressurized cylinders of Kr adsorbed on activated carbon. Fundamental principles

International Nuclear Information System (INIS)

Henrion, P.N.; Greff, J.F. de; Claes, W.; Leurs, A.

1979-01-01

Pressure of a few kg/cm 2 cause considerable adsorption of krypton on charcoal. In presence of this adsorbent, the aspects of krypton storage in a pressurized cylinder are modified in such a way that, eventually, a simplified engineered storage can be based on this procedure. As fission krypton generates heat and since the amount adsorbed is a function of temperature and pressure, there is no easy way of assessing the value of this concept. The purpose of this study was therefore to review the types of charcoal commercially available to examine their properties as adsorbents, as well as the thermal conductivity and the packing efficiency obtainable in beds made of these materials. The ways in which data are measured or estimated are explained in some detail. Heat transfer was evaluated by a simple mathematical model and, by means of selected values from the above data, realistic examples were treated, leading to explicit relationships between wall temperature, pressure and useful krypton load. Influence of krypton specific activity ( 85 Kr dilution) was also examined. The pressure vessels diameter is however of fundamental importance. The authors strongly recommend the use of specially designed, light-weight, relatively narrow pressure cylinders

Charter for the development of the super-ethanol E85 channel in France

International Nuclear Information System (INIS)

2006-01-01

Signed by more than 25 associations, or enterprises and the Government, this charter underlines eight main points in favor of the super-ethanol E85 development. Then the charter defines the actions plan allowing to assure the success of the launching and the development of the super-ethanol E85 channel: the necessary standards and technic, the diversified and impressive offer of flex-fuel vehicles, the E85 distribution network on the territory, the development of a competitive and sustainable channel of ethanol production, the economic and fiscal conditions allowing the E85 to be competitive facing the fossil fuels and the following of the actions plan. (A.L.B.)

A study on relative populations and gain coefficients of neon-like krypton for fast moving plasma in capillary discharges

International Nuclear Information System (INIS)

Masnavi, M.; Kikuchi, T.; Nakajima, M.; Horioka, K.

2002-01-01

X-ray laser gains and the level populations for collisionally pumped neon (Ne)-like Krypton (KrXXVII) ions have been studied considering the 27 - levels of the 2s 2 2p 6 , 2s 2 2p 5 3s, 2s 2 2p 5 3p and 2s 2 2p 5 3d configurations. It was found that large gains on the 3p 1 S 0 → 3s 3 P 1 , 3p 3 D 2 → 3s 3 P 1 , and 3p 3 S 1 → 3s 1 P 1 transitions are formed for the electron density between 10 20 and 10 22 cm -3 at the electron temperatures 0.9,1 and 3 keV. The effect of the opacity of the 3d 1 P 1 - 2p 61 S 0 , 3d 3 D 1 - 2p 61 S 0 , 3d 3 P 1 - 2p 61 S 0 , 3s 3 P 1 - 2p 61 S 0 and 3s 1 P 1 - 2p 61 S 0 transitions are performed using the escape probability factor approximation, for both the static and dynamic plasmas, which include the effect of the large velocity gradient. In addition, we found some theoretical line-intensity ratios that are sensitive on the electron density, the electron temperature, and also opacity in the interest regime of Ne-like Krypton x-ray laser. (author)

The Mycobacterium leprae antigen 85 complex gene family: identification of the genes for the 85A, 85C, and related MPT51 proteins

NARCIS (Netherlands)

Rinke de Wit, T. F.; Bekelie, S.; Osland, A.; Wieles, B.; Janson, A. A.; Thole, J. E.

1993-01-01

The genes for two novel members (designated 85A and 85C) of the Mycobacterium leprae antigen 85 complex family of proteins and the gene for the closely related M. leprae MPT51 protein were isolated. The complete DNA sequence of the M. leprae 85C gene and partial sequences of the 85A and MPT51 genes

Interaction between 4p photoionization and 3p resonant excitation channels of krypton

International Nuclear Information System (INIS)

Buhr, T.; Kover, A.; Varga, D.; Muller, A.; Ricz, S.; Justus-Liebig- Universitat Giessen, Giessen; Holste, K.; Borovik, Jr.A.A.; Bernhardt, D.; Schippers, S.

2011-01-01

Complete text of publication follows. The angular distribution of Kr 4p photoelectrons was measured employing a linearly polarized photon beam at energies from 205 eV to 230 eV. In this range the Kr 3p→ns/md (n,m=4,5,6, etc.) resonances can be excited. The experimental anisotropy parameters (β, γ and δ) were determined for the Kr 4p shell and its fine structure components. The measurement was carried out at beamline BW3 of the DORIS III synchrotron light source at HASYLAB (Hamburg, Germany). The ESA-22D electrostatic electron spectrometer was used to analyze the emitted electrons. The spectrometer consists of a spherical and a cylindrical mirror analyzer. The spherical mirror focuses the electrons from the scattering plane to the entrance slit of the cylindrical analyzer performing the energy analysis of the electrons. (For detailed description of an ESA- 22-type electron spectrometer see Ref. [1].) The measured dipole anisotropy parameters ? of Kr 4p photoelectrons are shown in Fig. 1 as a function of photon energy. Resonance-like structure can be seen in the photon energy dependence of the dipole parameters. This structure indicates that the channel interactions are important between the 3p resonant excitation-autoionization and 4p direct photoionization processes in krypton. The natural line width of the 3p photoelectron peaks was determined from the measured spectra and it is about 0.8 eV while the experimental width of the resonance near 220 eV photon energy (3p 1/2 -1 →5s resonant excitation) is approximately 2 eV in Fig. 1. This broadening can be explained with the strong interference between the ionization and excitation channels. As before, we conclude that the angular distribution of photoelectrons is strongly influenced by the excitation processes. Acknowledgements. The authors wish to thank the DORIS III staff for providing excellent working conditions. This work was supported by the NKTH-OTKA (Grant No. K67719), and by the European Community

Double shock front formation in cylindrical radiative blast waves produced by laser irradiation of krypton gas

Energy Technology Data Exchange (ETDEWEB)

Kim, I.; Quevedo, H. J.; Feldman, S.; Bang, W.; Serratto, K.; McCormick, M.; Aymond, F.; Dyer, G.; Bernstein, A. C.; Ditmire, T. [Center for High Energy Density Science, Department of Physics, The University of Texas at Austin, C1510, Austin, Texas 78712 (United States)

2013-12-15

Radiative blast waves were created by irradiating a krypton cluster source from a supersonic jet with a high intensity femtosecond laser pulse. It was found that the radiation from the shock surface is absorbed in the optically thick upstream medium creating a radiative heat wave that travels supersonically ahead of the main shock. As the blast wave propagates into the heated medium, it slows and loses energy, and the radiative heat wave also slows down. When the radiative heat wave slows down to the transonic regime, a secondary shock in the ionization precursor is produced. This paper presents experimental data characterizing both the initial and secondary shocks and numerical simulations to analyze the double-shock dynamics.

Distribution and abundance of the west Indian manatee Trichechus manatus around selected Florida power plants following winter cold fronts: 1984-85

Energy Technology Data Exchange (ETDEWEB)

Reynolds, J.E. III, Wilcox, J.R.

1986-01-01

Ten one-day aerial surveys were conducted in winter, 1984-85, to assess manatee distribution and abundance around five Florida Power and Light Company (FPL) plants: Cape Canaveral (PCC), Riviera (PRV), Port Everglades (PPE), Lauderdale (PFL) and Fort Myers (PFM). A total of 3804 manatees was observed, with a maximum of 636 animals for a single survey. Individual surveys for 1984-84 produced higher combined counts for all plants than in previous years. Maximum counts for PRV, PPE and PFM were the highest recorded for those particular plants. The maximum count for PCC in 1984-85 was lower than counts from most previous years, and the maximum from PFL was intermediate, relative to maxima from previous years. The counts along the east coast of Florida probably reflected a southward redistribution of manatees as well as very cold January weather after warm December conditions. The high count at PFM probably resulted from cold January weather and surface resting behavior by the manatees which made them more visible than usual. Calves represented 10 x 3% of the animals observed near the FPL plants and in Hobe Sound. PFM had a higher percentage of calves than did other plants.

Krypton laser treatment of　neovascularization in retinal vein occlusion%氪激光治疗视网膜静脉阻塞的新生血管

Institute of Scientific and Technical Information of China (English)

吴又凯; 武志峰; 张清

2001-01-01

Objective　To investigate the method and effect of krypton laser photocoagulation for neovascularization in retinal vein occlusion.　Methods　Tweenty eight eyes of 27 patients with retinal vein occlusion with neovascularization were photocoagulated by krypton-green and-red laser.The fundus changes were observed by fundus fluorescein angiography after photocoagulation.　Results　The neovascularization disappeared completely in 20 eyes and became smaller in 6 eyes,remained no-change in 2 eyes,and the visual acuity improved in 17 eyes (60.7%) after 6 monthes to 2.5 years of follow-up.　Conclusion　Krypton laser photocoagulation is obviously effective on regression of neovascularization and prevenion of vitreous hemorrhage in retinal vein occlusion.%目的探讨氪激光治疗视网膜静脉阻塞新生血管的方法和疗效。方法对27例视网膜静脉阻塞伴有新生血管的28只患眼采用氪绿、氪红激光进行光凝治疗。光凝后经6个月～2．5年随访，对比分析光凝前后的荧光素眼底血管造影及视力变化情况。结果新生血管萎缩20只眼，占71．4％，好转6只眼，占21．4%，无效2只眼，占7．2%。视力进步17只眼，占60．7%。结论氪激光光凝术对视网膜静脉阻塞新生血管的消退及预防其玻璃体积血具有显著疗效。

The Upgrade of the Control System for the CERN/NA62 Liquid Krypton Detector

CERN Document Server

Moraux, A; Bremer, J; Falaleev, V; Gonidec, A; Passardi, Giorgio; Pezzetti, M

2009-01-01

The NA62 experiment is a continuation of the CERN kaon research program and particularly of the NA48 experiment which was designed in the early 90’s to measure the direct CP violation with a very high precision. An important component of the experimental setup is an electromagnetic calorimeter filled with 9000 liters of high-purity liquid krypton at 120 K. Its associated cryogenic system aims at providing a very high reliability and stable thermal conditions with temperature stabilization better than 0.1 K. The upgrade of the cryogenic control system was motivated by the need of ensuring its durability and standardization for the long term fixed-target physics program at the CERN Super Proton Synchrotron (SPS). This paper describes the adopted technical solutions to minimize the control shutdown and emphasizes the related safety issues.

Study of particle size distribution and formation mechanism of radioactive aerosols generated in high-energy neutron fields

CERN Document Server

Endo, A; Noguchi, H; Tanaka, S; Iida, T; Furuichi, S; Kanda, Y; Oki, Y

2003-01-01

The size distributions of sup 3 sup 8 Cl, sup 3 sup 9 Cl, sup 8 sup 2 Br and sup 8 sup 4 Br aerosols generated by irradiations of argon and krypton gases containing di-octyl phthalate (DOP) aerosols with 45 MeV and 65 MeV quasi-monoenergetic neutrons were measured in order to study the formation mechanism of radioactive particles in high energy radiation fields. The effects of the size distribution of the radioactive aerosols on the size of the added DOP aerosols, the energy of the neutrons and the kinds of nuclides were studied. The observed size distributions of the radioactive particles were explained by attachment of the radioactive atoms generated by the neutron-induced reactions to the DOP aerosols. (author)

First Detection of Krypton and Xenon in a White Dwarf

Science.gov (United States)

Werner, Klaus; Rauch, Thomas; Ringat, Ellen; Kruk, Jeffrey W.

2012-01-01

We report on the first detection of the noble gases krypton (Z = 36) and xenon (54) in a white dwarf. About 20 KrVI-VII and Xe VI-VII lines were discovered in the ultraviolet spectrum of the hot DO-type white dwarf RE 0503-289. The observations, performed with the Far Ultraviolet Spectroscopic Explorer, also reveal highly ionized photospheric lines from other trans-iron group elements, namely Ga (31), Ge (32), As (33), Se (34), Mo (42), Sn (50), Te (52), and I (53), from which gallium and molybdenum are new discoveries in white dwarfs, too. For Kr and Xe, we performed an NLTE analysis and derived mass fractions of log Kr = -4.3 plus or minus 0.5 and log Xe = -4.2 plus or minus 0.6, corresponding to an enrichment by factors of 450 and 3800, respectively, relative to the Sun. The origin of the large overabundances is unclear. We discuss the roles of neutron-capture nucleosynthesis in the-precursor star and radiation-driven diffusion. It is possible that diffusion is insignificant and thaI the observed metal abundances constrain the evolutionary history of the star. Its hydrogen deficiency may be the consequence of a late helium-shell nash or a binary white dwarf merger.

Ccdc85C, a causative protein for hydrocephalus and subcortical heterotopia, is expressed in the systemic epithelia with proliferative activity in rats.

Science.gov (United States)

Tanaka, Natsuki; Izawa, Takeshi; Takenaka, Shigeo; Yamate, Jyoji; Kuwamura, Mitsuru

2015-07-01

Coiled-coil domain containing 85c (Ccdc85c) is a causative gene for spontaneous mutant mouse with non-obstructive hydrocephalus and subcortical heterotopia. Detailed functions of Ccdc85C protein have not been clarified. To reveal roles of Ccdc85C, we examined the distribution and expression pattern of Ccdc85C in the systemic developing organs in rats. Ccdc85C was expressed in various simple epithelia but not stratified epithelia. In the various epithelia, Ccdc85C was localized at cell-cell junctions and its expression was strong at apical junctions. Furthermore, intense expression was seen at developing period and gradually decreased with advancing development. Distribution of Ccdc85C coincides with that of proliferating epithelial cells. These results suggest that Ccdc85C plays an important role in the proliferative property of simple epithelia.

Electronic structure of the actinides and their dioxides. Application to the defect formation energy and krypton solubility in uranium dioxide

International Nuclear Information System (INIS)

Petit, T.; CEA Centre d'Etudes de Grenoble, 38

1996-01-01

Uranium dioxide is the standard nuclear fuel used in French h power plants. During irradiation, fission products such as krypton and xenon are created inside fuel pellets. So, gas release could become, at very high burnup, a limiting factor in the reactor exploitation. To study this subject, we have realised calculations using the Density Functional Theory (DFT) into the Local Density Approximation (LDA) and the Atomic Sphere Approximation (ASA). First, we have validated our approach by calculating cohesive properties of thorium, protactinium and uranium metals. The good agreement between our results and experimental values implies that 5f electrons are itinerant. Calculated lattice parameter, cohesive energy and bulk modulus for uranium and thorium dioxides are in very good agreement with experiment. We show that binding between uranium and oxygen atoms is not completely ionic but partially covalent. The question of the electrical conductivity still remains an open problem. We have been able to calculate punctual defect formation energies in uranium dioxide. Accordingly to experimental observations, we find that it is easier to create a defect in the oxygen sublattice than in the uranium sublattice. Finally, we have been able to predict a probable site of krypton atoms in nuclear fuel: the Schottky trio. Experiences of Extended X-ray Absorption Fine structure Spectroscopy (EXAFS) and X-ray Photoelectron Spectroscopy (XPS) on uranium dioxide doped by ionic implantation will help us in the comprehension of the studied phenomena and the interpretation of our calculations. (author)

H3(+) as a trap for noble gases-3: multiple trapping of neon, argon, and krypton in X(n)H3(+) (n = 1-3).

Science.gov (United States)

Pauzat, F; Ellinger, Y; Pilmé, J; Mousis, O

2009-05-07

Recent studies on the formation of XH(3)(+) noble gas complexes have shown strategic implications for the composition of the atmospheres of the giant planets as well as for the composition of comets. One crucial factor in the astrophysical process is the relative abundances of the noble gases versus H(3)(+). It is the context in which the possibility for clustering with more than one noble gas (X(n)H(3)(+) up to n = 3) has been investigated for noble gases X ranging from neon to krypton. In order to assert our results, a variety of methods have been used including ab initio coupled cluster CCSD and CCSD(T), MP2, and density functional BH&HLYP levels of theory. All complexes with one, two, and three noble gases are found to be stable in the Ne, Ar, and Kr families. These stable structures are planar with the noble gases attached to the apices of the H(3)(+) triangle. The binding energy of the nth atom, defined as the X(n)H(3)(+) --> X(n-1)H(3)(+) + X reaction energy, increases slightly with n varying from 1 to 3 in the neon series, while it decreases in the argon series and shows a minimum for n = 2 in the krypton series. The origin of this phenomenon is to be found in the variations in the respective vibrational energies. A topological analysis of the electron localization function shows the importance of the charge transfer from the noble gases toward H(3)(+) as a driving force in the bonding along the series. It is also consistent with the increase in the atomic polarizabilities from neon to krypton. Rotational constants and harmonic frequencies are reported in order to provide a body of data to be used for the detection in laboratory prior to space observations. This study strongly suggests that the noble gases could be sequestered even in an environment where the H(3)(+) abundance is small.

A megajoule class krypton fluoride amplifier for single shot, high gain ICF application

International Nuclear Information System (INIS)

Rose, E.; Hanson, D.; Krohn, B.; McLeod, J.; Kang, M.

1988-01-01

A design study is underway to define the optimal architecture for a KrF laser system which will deliver 10 MJ of 248-nm light to an ICF target. We present one approach which incorporates final power amplifiers in the megajoule class, achieving 10 MJ with four final amplifiers. Each double-pass laser amplifier employs two-sided electron-beam pumping of the laser gas medium. Details of the design are based on a Monte-Carlo electron-beam deposition code, a one-dimensional, time-dependent kinetics code, and pulsed power circuit modeling. Linear dimensions of the amplifier's extracted gain volume are 6.25 m in height and length and 5.12 m in width. Each amplifier handles 160 angularly multiplexed laser channels. The one-amagat, krypton-rich laser medium is e-beam pumped at 60-kW cm/sup /minus/3/ (4-MA at3.3-MV) over the 2-microsecond duration of the laser beam pulse train. 5 refs., 4 figs

Oxygenated fuel (M-85) behavior in the subsurface -- A Laboratory scale investigation

International Nuclear Information System (INIS)

Donaldson, C.R.; Barker, J.F.; Chatzis, I.

1993-01-01

M-85 is an oxygenated fuel consisting of 85% methanol and 15% gasoline. The complete miscibility of methanol with water may lead to a significantly different source behavior and contamination scenario for M-85 relative to a conventional gasoline. A laboratory investigation involving phase equilibria, cosolvency and column experiments was designed to assess the subsurface behavior of M-85 in comparison to API PS-6 gasoline. Liquid-liquid equilibrium determinations have indicated that unlike PS-6, which is essentially immiscible with water, M-85 would behave as a single miscible phase with groundwater under certain conditions. However, as mixing with groundwater proceeded, two distinct, immiscible phases would result. Column experiments involved the injection of a slug of M-85 or PS-6 onto a saturated, packed column of Borden sand. Aqueous BTEX and methanol breakthrough curves were prepared based on column effluent analyses. Subsequent soil sample analyses provided information regarding the residual gasoline phase distributions from each source. The results of the column experiments indicated that the groundwater contamination arising from an M-85 source would be more complex than from PS-6. The plume of dissolved organic compounds migrating from an M-85 source was characterized by a high methanol content front and associated enhanced BTEX concentrations relative to PS-6, due to methanol's cosolubility effects

Clinical Abservation of Krypton Laser Photocoagulation Preventing Retinal Detachment after LASIK on High Myopia%眼底激光预防中高度近视LASIK术后视网膜脱离的临床观察

Institute of Scientific and Technical Information of China (English)

周建平; 胡莉群; 胡长青

2014-01-01

目的观察LASIK术前对中高度近视患者行预防性眼底激光光凝的疗效。方法准备接受LASIK手术的中高度近视患者作详细眼底检查，直接眼底镜、间接眼底镜和三面镜检查明确有视网膜变性或(和)干性裂孔的患者共61例(112眼)行氪激光光凝治疗。结果61例(112眼)患者氪激光光凝术后变性区及裂孔封闭良好，未发生视网膜脱离。结论对明确有视网膜变性和裂孔的中高度近视患者LASIK术前行氪激光光凝是预防LASIK术后发生孔源性视网膜脱离的一种安全有效的方法。%Objective To observe the effect of krypton laser photocoagulation before LASIK on high myopia. Methods Full fundus examination on high myopic patients was performed with direct ophthalmoscopy, indirect ophthalmoscopy and three mirror contact lens. 112 eyes of 61 patients with peripheral retinal degeneration or retinal hole were treated by krypton laser photocoagulation before LASIK. Results 112 eyes of 61 patients with peripheral retinal degeneration or retinal hole were stable after krypton laser photocoagulation.No retinal detachment was occurred. Conclusion The krypton laser photocoagulation is a safe and ef ective method to preventing retinal detachment for the patients with peripheral retinal degeneration or retinal hole.

38 CFR 3.953 - Pub. L. 85-56 and Pub. L. 85-857.

Science.gov (United States)

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Pub. L. 85-56 and Pub. L... ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Protection § 3.953 Pub. L. 85-56 and Pub. L. 85-857. (a) In receipt of or entitled to receive benefits on December 31, 1958. Any person...

Selective noble gases monitoring

International Nuclear Information System (INIS)

Janecka, S.; Jancik, O.; Kapisovsky, V.; Kubik, I.; Sevecka, S.

1995-01-01

The monitoring of leak releases from ventilation stack of NPP requires a system by several orders more sensitive then currently used radiometer Kalina, designed to cover the range up to a design-based accident. To reach this goal a noble gases monitor with a germanium detector (MPVG) has been developed. It enables nuclide selective monitoring of current value of volume activity of particular nuclides in ventilation stack and daily releases of noble gases (balancing). MPVG can be viewed as a system build of three levels of subsystem: measuring level; control level; presentation level. Measuring level consists of gamma-spectroscopy system and operational parameters monitoring unit (flow rate, temperature, humidity). Control level provides communication between presentation and measuring level, acquisition of operational parameters and power supply. The presentation level of MPVG enables: 1) the measured data storage in predetermined time intervals; 2) the presentation of measured and evaluated values of radiation characteristics. The monitored radionuclides - default set: argon-41, krypton-85m, krypton-87, krypton-88, krypton-89, xenon-131m, xenon-133, xenon-133m, xenon-135, xenon-135m, xenon-137 and xenon-138. The values of volume activities observed at maximum releases have been approximately ten times higher. In that case in balancing some other nuclides exceed corresponding detection limits: 88 Kr(67; 22) Bq/m 3 ; 85m Kr(17; 7) Bq/m 3 ; 135m Xe(7.1; 0.5) Bq/m 3 ; 138 Xe(5.9; 0.9) Bq/m 3 . (J.K.)

Selective noble gases monitoring

Energy Technology Data Exchange (ETDEWEB)

Janecka, S; Jancik, O; Kapisovsky, V; Kubik, I; Sevecka, S [Nuclear Power Plants Research Institute, a.s., Trnava (Slovakia)

1996-12-31

The monitoring of leak releases from ventilation stack of NPP requires a system by several orders more sensitive then currently used radiometer Kalina, designed to cover the range up to a design-based accident. To reach this goal a noble gases monitor with a germanium detector (MPVG) has been developed. It enables nuclide selective monitoring of current value of volume activity of particular nuclides in ventilation stack and daily releases of noble gases (balancing). MPVG can be viewed as a system build of three levels of subsystem: measuring level; control level; presentation level. Measuring level consists of gamma-spectroscopy system and operational parameters monitoring unit (flow rate, temperature, humidity). Control level provides communication between presentation and measuring level, acquisition of operational parameters and power supply. The presentation level of MPVG enables: 1) the measured data storage in predetermined time intervals; 2) the presentation of measured and evaluated values of radiation characteristics. The monitored radionuclides - default set: argon-41, krypton-85m, krypton-87, krypton-88, krypton-89, xenon-131m, xenon-133, xenon-133m, xenon-135, xenon-135m, xenon-137 and xenon-138. The values of volume activities observed at maximum releases have been approximately ten times higher. In that case in balancing some other nuclides exceed corresponding detection limits: {sup 88}Kr(67; 22) Bq/m{sup 3}; {sup 85m}Kr(17; 7) Bq/m{sup 3}; {sup 135m}Xe(7.1; 0.5) Bq/m{sup 3}; {sup 138}Xe(5.9; 0.9) Bq/m{sup 3}. (J.K.).

Self-Associating Behavior of Acetone in Liquid Krypton.

Science.gov (United States)

De Beuckeleer, Liene I; Herrebout, Wouter A

2016-02-18

Acetone molecules are inclined to self-associate through dipole-dipole interactions because of their large dipole moment. Infrared spectroscopy of compounds dissolved in liquid noble gases supported by high level ab initio calculations allows investigating the self-associating behavior and determining the thermodynamical properties. In this study, infrared spectra of various concentrations of acetone dissolved in liquid krypton are recorded at constant temperature. Overlapping monomer and dimer spectra are separated by analyzing the obtained data sets with numerical methods based on least-squares fitting. Although acetone is known to self-associate, only a few spectral features have been presented in literature before. In this study, the application of new numerical approaches succeeds in resolving overlapping spectra and allows observing isolated acetone dimer absorption bands for the complete mid infrared spectrum. By use of data sets of spectra recorded at temperatures between 134 and 142 K, the experimental standard dimerization enthalpy was determined to be -10.8 kJ mol(-1). MP2/aug-cc-pVDZ calculations predicted a stacked and planar dimer geometry of which the stacked geometry is more stable. Combining MP2 energies and single point corrections involving CCSD(T) calculations and complete basis set extrapolations based on the MP2/aug-cc-pVDZ equilibrium geometry lead to complexation energy of -28.4 kJ mol(-1) for the stacked geometry and -15.1 kJ mol(-1) for the planar geometry. The corresponding values for the complexation enthalpies in solution, obtained by combining these values with corrections for thermal and solvent influences are -13.7 and -5.8 kJ mol(-1).

Soft X-ray images of krypton gas-puff Z-pinches

International Nuclear Information System (INIS)

Qiu Mengtong; Kuai Bin; Zeng Zhengzhong; Lu Min; Wang Kuilu; Qiu Aici; Zhang Mei; Luo Jianhui

2002-01-01

A series of experiments has been carried out on Qiang-guang I generator to study the dynamics of krypton gas-puff Z-pinches. The generator was operated at a peak current of 1.5 MA with a rise-time of 80 ns. The specific linear mass of gas liner was about 20 μg/cm in these experiments. In the diagnostic system, a four-frame x-ray framing camera and a pinhole camera were employed. A novel feature of this camera is that it can give time-resolved x-ray images with four frames and energy-resolved x-ray images with two different filters and an array of 8 pinholes integrated into one compact assemble. As a typical experimental result, an averaged radial imploding velocity of 157 km/s over 14 ns near the late phase of implosion was measured from the time-resolved x-ray images. From the time-integrated x-ray image an averaged radial convergence of 0.072 times of the original size was measured. An averaged radial expansion velocity was 130 km/s and the maximum radial convergence of 0.04 times of the original size were measured from the time-resolved x-ray images. The dominant axial wavelengths of instabilities in the plasma were between 1 and 2 mm. The change in average photons energy was observed from energy spectrum- and time-resolved x-ray images

Soft X-ray Images of Krypton Gas-Puff Z-Pinches

Institute of Scientific and Technical Information of China (English)

邱孟通; 蒯斌; 曾正中; 吕敏; 王奎禄; 邱爱慈; 张美; 罗建辉

2002-01-01

A series of experiments has been carried out on Qiang-guang Ⅰ generator to study the dynamics of krypton gas-puff Z-pinches. The generator was operated at a peak current of 1.5 MA with a rise-time of 80 ns. The specific linear mass of gas liner was about 20 μg/cm in these experiments. In the diagnostic system, a four-frame x-ray framing camera and a pinhole camera were employed. A novel feature of this camera is that it can give time-resolved x-ray images with four frames and energy-resolved x-ray images with two different filters and an array of 8 pinholes integrated into one compact assemble. As a typical experimental result, an averaged radial imploding velocity of 157 km/s over 14 ns near the late phase of implosion was measured from the time-resolved x-ray images. From the time-integrated x-ray image an averaged radial convergence of 0.072 times of the original size was measured. An averaged radial expansion velocity was 130 km/s and the maximum radial convergence of 0.04 times of the original size were measured from the time-resolved x-ray images. The dominant axial wavelengths of instabilities in the plasma were between 1 and 2 mm. The change in average photons energy was observed from energy spectrum- and time-resolved x-ray images.

Shape Evolution in Neutron-Rich Krypton Isotopes Beyond N=60: First Spectroscopy of ^{98,100}Kr.

Science.gov (United States)

Flavigny, F; Doornenbal, P; Obertelli, A; Delaroche, J-P; Girod, M; Libert, J; Rodriguez, T R; Authelet, G; Baba, H; Calvet, D; Château, F; Chen, S; Corsi, A; Delbart, A; Gheller, J-M; Giganon, A; Gillibert, A; Lapoux, V; Motobayashi, T; Niikura, M; Paul, N; Roussé, J-Y; Sakurai, H; Santamaria, C; Steppenbeck, D; Taniuchi, R; Uesaka, T; Ando, T; Arici, T; Blazhev, A; Browne, F; Bruce, A; Carroll, R; Chung, L X; Cortés, M L; Dewald, M; Ding, B; Franchoo, S; Górska, M; Gottardo, A; Jungclaus, A; Lee, J; Lettmann, M; Linh, B D; Liu, J; Liu, Z; Lizarazo, C; Momiyama, S; Moschner, K; Nagamine, S; Nakatsuka, N; Nita, C; Nobs, C R; Olivier, L; Orlandi, R; Patel, Z; Podolyák, Zs; Rudigier, M; Saito, T; Shand, C; Söderström, P A; Stefan, I; Vaquero, V; Werner, V; Wimmer, K; Xu, Z

2017-06-16

We report on the first γ-ray spectroscopy of low-lying states in neutron-rich ^{98,100}Kr isotopes obtained from ^{99,101}Rb(p,2p) reactions at ∼220  MeV/nucleon. A reduction of the 2_{1}^{+} state energies beyond N=60 demonstrates a significant increase of deformation, shifted in neutron number compared to the sharper transition observed in strontium and zirconium isotopes. State-of-the-art beyond-mean-field calculations using the Gogny D1S interaction predict level energies in good agreement with experimental results. The identification of a low-lying (0_{2}^{+}, 2_{2}^{+}) state in ^{98}Kr provides the first experimental evidence of a competing configuration at low energy in neutron-rich krypton isotopes consistent with the oblate-prolate shape coexistence picture suggested by theory.

Tests of the GIC and Measurements of Angular Distributions and Energy Spectra for 58Ni（n,p）58Co Reaction at 4.1 MeV

Institute of Scientific and Technical Information of China (English)

Yu.M.Gledenov; M.Sedysheva; G.Khuukhenkhuu

1997-01-01

<正>On the basis of measurements of double differential cross sections for （n,α） reactions in 5-7 MeV neutron energy region using gridded ionization chamber （GIC）, we constructed a new GIC which, compared with the old ones, can bear higher pressure and makes it possible to measure （n,p） reactions up to 6 MeV and （n,xα） reactions up to 20 MeV. To test the new chamber, the saturation property for argon and krypton mixed with a few percent CO2 was studied using 241Am and compound Pu α source and tritium from 6Li(nth,t)4He, and the two dimensional spectra for 241Am and Pu α source, 6Li(nth,t)4He and H（n,p） reactions were measured. The measured energy spectra and angular distributions for α and tritium are reasonable, and the derived data for α, proton and tritium in argon and krypton from the measured spectra data were compared with the calculated ones. They are in good agreement. The angular distributions and energy spectra for 58Ni（n,p）58Co reaction at 4.1 MeV neutron energy were m

Influence du type d’addition minérale sur les propriétés de transfert des Bétons AutoPlaçants Influence of the type of mineral admixtures on the transport properties of self compacting concrete

Directory of Open Access Journals (Sweden)

Khelafi H.

2012-09-01

Full Text Available La formulation des bétons autoplaçants (BAP présente certaines spécificités dont un volume élevé de pâte et une quantité importante d’ajouts minéraux. Ces deux paramètres influencent sensiblement les propriétés de transfert de ces bétons. Dans ce travail, nous avons étudié l’influence de la nature et du pourcentage de plusieurs additions minérales sur certaines propriétés de transfert (la diffusion des ions chlore et la perméabilité au gaz des BAP. Trois différentes additions minérales ont été testées : des fillers calcaires, de la pouzzolane naturelle et des cendres volantes. Ensuite, nous avons cherché une probable relation analytique entre ces propriétés et la résistance à la compression de ces bétons. Au total, douze formulations ont été étudiées, elles couvrent trois différentes classes de résistances (30 MPa, 50 MPa et 70 MPa et quatre types de bétons: un béton ordinaire vibré, un BAP à base de pouzzolanes naturelles, un BAP à base de fillers calcaires et un BAP à base de cendres volantes. Les résultats montrent que la nature de l’addition minérale dans les BAP influe considérablement sur les propriétés de transferts de ces bétons. Après 28, 90 et 360 jours de cure, les BAP contenant de la pouzzolane naturelle représentent des performances très comparables à celles obtenues sur des BAP à base de cendres volantes et bien meilleures que celles obtenues sur des BAP formulés avec du filler calcaire. Indépendamment du type d’addition minérale, les résultats confirment l’existence d’une forte corrélation entre le développement de la résistance à la compression et les propriétés de transferts des BAP. Formulation of self compacting concrete (SCC has some specific characteristics including a high volume of paste and a large amount of mineral admixtures. These two parameters influence significantly the transport properties of SCC. In this work, we studied the influence of

Total projectile electron loss cross sections of U^{28+} ions in collisions with gaseous targets ranging from hydrogen to krypton

Directory of Open Access Journals (Sweden)