Determination of lithium, rubidium and strontium in foodstuffs

International Nuclear Information System (INIS)

Evans, W.H.; Read, J.I.

1985-01-01

For the determination of total lithium, rubidium and strontium in foodstuffs the organic matter is destroyed by a wet-oxidation procedure. Both lithium and rubidium are measured by flame atomic-emission spectrophotometry, rubidium with the addition of a radiation buffer and strontium is measured by flame atomic-absorption spectrophotometry using the same radiation buffer. The optimum conditions for measurement are described and interferences noted. The accuracy of the method was assessed by measuring the recovery of these metals from foodstuff homogenates and values for standard reference materials are listed, for comparison with certified levels where these exist. From the results obtained standard deviations were calculated and derived limits of detection and confidence intervals are given. (author)

Separation of rubidium from irradiated aluminum-encapsulated uranium

International Nuclear Information System (INIS)

Horwitz, E.P.; Schmitz, F.J.; Rokop, D.J.

1982-01-01

A procedure was developed for separating rubidium from irradiated aluminum encapsulated uranium. The separations procedure produces a final ultra-high purity RbCl product for subsequent high performance mass spectrometric analysis. The procedure involves first removing most of the macro-components and fission products by strong base anion exchange using, first, concentrated HCl, then oxalic acid media and second, selectively separating rubidium from alkaline-earth ions and other alkali-metal ions, including cesium, using Bio-Rex-40 cation-exchange resin. The resultant RbCl is then put through a final vacuum sublimation step. Ultra-pure reagents and specially clean glassware are used throughout the procedure to minimize contamination by naturally-occurring rubidium

Sympathetic cooling in a rubidium cesium mixture: Production of ultracold cesium atoms

International Nuclear Information System (INIS)

Haas, M.

2007-01-01

This thesis presents experiments for the production of ultracold rubidium cesium mixture in a magnetic trap. The long-termed aim of the experiment is the study of the interaction of few cesium atoms with a Bose-Einstein condensate of rubidium atoms. Especially by controlled variation of the cesium atom number the transition in the description of the interaction by concepts of the one-particle physics to the description by concepts of the many-particle physics shall be studied. The rubidium atoms are trapped in a magneto-optical trap (MOT) and from there reloaded into a magnetic trap. In this the rubidium atoms are stored in the state vertical stroke f=2,m f =2 right angle of the electronic ground state and evaporatively cooled by means of microwave-induced transitions into the state vertical stroke f=1,m f =1] (microwave cooling). The cesium atoms are also trppaed in a MOT and into the same magnetic trap reloaded, in which they are stored in the state vertical stroke f=4,m f =4 right angle of the electronic ground state together with rubidium. Because of the different hyperfine splitting only rubidium is evaporatively cooled, while cesium is cooled jointly sympathetically - i.e. by theramal contact via elastic collisions with rubidium atoms. The first two chapters contain a description of interatomic interactions in ultracold gases as well as a short summary of theoretical concepts in the description of Bose-Einstein condensates. The chapters 3 and 4 contain a short presentation of the methods applied in the experiment for the production of ultracold gases as well as the experimental arrangement; especially in the framework of this thesis a new coil system has been designed, which offers in view of future experiments additionally optical access for an optical trap. Additionally the fourth chapter contains an extensive description of the experimental cycle, which is applied in order to store rubidium and cesium atoms together into the magnetic trap. The last chapter

Substoichiometric extraction of rubidium with Dibenzo-24-crown-8 into Xylene

International Nuclear Information System (INIS)

Bag, M.; Chattopadhyay, P.; Basu, S.

2014-01-01

Owing to immense applications of rubidium in varied fields, extraction and quantification of rubidium have gained great importance in recent years. Here, studies on substoichiometric extraction of rubidium by dibenzo-24-crown-8 into xylene using 86 Rb radiotracer are reported. The method has been optimized by pH of the medium, effects of diverse ions, etc, to explore its applicability in real samples

Rubidium-strontium chronology of the metamorphism and prehistory of central Australian granulites

Energy Technology Data Exchange (ETDEWEB)

Gray, C M [La Trobe Univ., Bundoora (Australia); Compston, W

1978-11-01

Rubidium-strontium isotopic study of intermediate-pressure granulites at Mt. Aloysius, central Australia reveals total rock isochrons that either record the metamorphism or predate it. The gneisses involved, typically quartz + feldspar + orthopyroxene + garnet granulites, occur in five lithological units which outline a simple fold structure. The distribution of isotopic ages in a 25 km/sup 2/ area is tested using 74 samples collected in groups of 2 to 4 both along and across strike in each of the units. Two total rock isochron ages of 1200 and 1550 Myr occur, and both are found at different sites in one unit. Mineral ages are younger and independent of location, with feldspars giving 800 Myr and biotites 730 Myr. The 1200 Myr isochrons show the features of outcrop-scale Sr isotopic homogenisation and are taken to record the time of metamorphism. Contemporaneous regional depletion of U, commonly associated with granulite facies metamorphism, confirms the interpretation. The 1550 Myr isochrons describe entire lithological units and are best assigned to the supracrustal genesis of the rocks. The preservation of two ages indicates that isotopic equilibration of anhydrous total rocks is incomplete even within the granulite facies. Careful interpretation is required to assign geological meaning to granulite isochrons.

Addendum to ''Density fluctuations in liquid rubidium''

International Nuclear Information System (INIS)

Haan, S.W.; Mountain, R.D.; Hsu, C.S.; Rahman, A.

1980-01-01

We performed molecular-dynamics simulations of liquid rubidium and the Lennard-Jones fluid at several densities and temperatures, and of a system whose pair potential is the repulsive core of the rubidium potential. In all cases, propagating density fluctuations occurred in the rubidiumlike systems at much shorter wavelengths than in the Lennard-Jones system. This indicates that the repulsive part of the pair potential is the dominant factor in determining the relaxation of short-wavelength density fluctuations

Stage structure and electrical properties of rubidium-doped pentacene

International Nuclear Information System (INIS)

Matsuo, Yasumitsu; Sasaki, Sachio; Ikehata, Seiichiro

2004-01-01

We have investigated the structural and electrical properties on the molecular conductor based on pentacene doped with rubidium. It was found from the X-ray diffraction measurement that the rubidium-doped pentacene becomes a highly oriented film with a stage-1 structure, as seen in graphite intercalated compounds. It was also found from this result that the length between pentacene molecular layers increases from 1.51 nm of pure pentacene to 1.62 nm. Moreover, the result of the electrical conductivity measurement shows that by doping of rubidium electrical conductivity at room temperature increases above 10 8 times larger than that of pure pentacene. We have also found that the electrical conductivity along the a-b plane (parallel to the molecular layers) is 10 2 times larger than that along the c-axis which is perpendicular to the molecular layers. These results indicate that pentacene doped with rubidium becomes a molecular conductor and displays the quasi-two-dimensional conductivity

Strontium-rubidium infusion pump with in-line dosimetry

International Nuclear Information System (INIS)

Barker, S.L.; Loberg, M.D.

1986-01-01

A strontium-rubidium infusion system is described which consists of: (a) means for generating rubidium 82 in a solution which can be infused into a patient; (b) means for infusing the solution into a patient; (c) means for measuring the radioactivity present in the solution as it is infused into the patient; and (d) means for controlling the means for infusing in response to the amount of radioactivity which has been infused into the patient

The effects of potassium and rubidium hydroxide on the alkali-silica reaction

International Nuclear Information System (INIS)

Shomglin, K.; Turanli, L.; Wenk, H.-R.; Monteiro, P.J.M.; Sposito, G.

2003-01-01

Expansion of mortar specimens prepared with an aggregate of mylonite from the Santa Rosa mylonite zone in southern California was studied to investigate the effect of different alkali ions on the alkali-silica reaction in concrete. The expansion tests indicate that mortar has a greater expansion when subjected to a sodium hydroxide bath than in a sodium-potassium-rubidium hydroxide bath. Electron probe microanalysis (EPMA) of mortar bars at early ages show that rubidium ions, used as tracer, were present throughout the sample by the third day of exposure. The analysis also shows a high concentration of rubidium in silica gel from mortar bars exposed to bath solutions containing rubidium. The results suggest that expansion of mortar bars using ASTM C 1260 does not depend on the diffusion of alkali ions. The results indicate that the expansion of alkali-silica gel depends on the type of alkali ions present. Alkali-silica gel containing rubidium shows a lower concentration of calcium, suggesting competition for the same sites

Synthesis of condensed double rubidium manganese phosphates in melts of polyphosphoric acids

International Nuclear Information System (INIS)

Guzeeva, L.S.; Tananaev, I.V.

1988-01-01

The aim of this work was to study the character of the reaction of MnO 2 and Rb 2 O with melts of polyphosphoric acids, and to establish the composition and the conditions of formation of the condensed double rubidium manganese phosphates. In the reaction of manganese and rubidium oxides with melts of polyphosphoric acids at 140-350 degree C, three types of trivalent manganese and rubidium condensed double phosphates are formed - diphosphates RbMn(H 2 P 2 O 7 ) and Rb 2 MnH 3 (P 2 O 7 ) 2 , triphosphate RbMnHP 3 O 10 and diphosphate RbMnP 2 O 7 - in addition to a double cyclotriphosphate of divalent manganese with rubidium RbMnP 3 O 9 . The thermal transformations of the compound isolated were studied. It was shown that rubidium manganese cyclotriphosphate can be obtained by the thermal decomposition of the diphosphate RbMn(H 2 P 2 O 7 ) 2

Model potential for electron scattering from rubidium

Energy Technology Data Exchange (ETDEWEB)

Gien, T.E. (Memorial Univ. of Newfoundland, St. John' s, NF (Canada). Dept. of Physics)

1992-11-28

An analytic model potential for the e[sup -]-Rb[sup +] system is generated from experimental data, using an iteration method. The potential obtained can reproduce rather accurately the energy levels of rubidium. We employed it in the calculation of elastic differential cross sections for electron (and positron) scatterings from rubidium in the conventional Glauber approximation. The differential cross sections calculated in the model potential approach are compared to those in the frozen-core approach, employing either the Clementi-Roetti or the Szasz-McGinn wavefunctions. The core correlation and polarization effects are found to significantly affect the cross section results. (author).

Model potential for electron scattering from rubidium

International Nuclear Information System (INIS)

Gien, T.E.

1992-01-01

An analytic model potential for the e - -Rb + system is generated from experimental data, using an iteration method. The potential obtained can reproduce rather accurately the energy levels of rubidium. We employed it in the calculation of elastic differential cross sections for electron (and positron) scatterings from rubidium in the conventional Glauber approximation. The differential cross sections calculated in the model potential approach are compared to those in the frozen-core approach, employing either the Clementi-Roetti or the Szasz-McGinn wavefunctions. The core correlation and polarization effects are found to significantly affect the cross section results. (author)

Rubidium-strontium and uranium-lead isotopic age studies

International Nuclear Information System (INIS)

Loveridge, W.D.

1981-01-01

The results of five Rb-Sr isotopic age studies predominantly on whole-rock samples, and six U-Pb studies on zircon monazite concentrates are presented. Descriptions of the geological problems and interpretations of the measured ages are included. Laboratory age determination methods and techniques are described or referenced

Selective Bioaccumulation of Rubidium by Microalgae from Industrial Wastewater Containing Rubidium and Lithium.

Czech Academy of Sciences Publication Activity Database

Kaštánek, P.; Kronusová, O.; Kaštánek, František; Brányiková, Irena; Prochazková, G.; Jandová, J.; Brányik, T.; Bišová, Kateřina

2018-01-01

Roč. 30, č. 1 (2018), s. 461-467 ISSN 0921-8971 R&D Projects: GA TA ČR TE01020080 Institutional support: RVO:67985858 ; RVO:61388971 Keywords : rubidium * lithium * microalgae Subject RIV: CI - Industrial Chemistry, Chemical Engineering; EE - Microbiology, Virology (MBU-M) OBOR OECD: Chemical process engineering; Microbiology (MBU-M) Impact factor: 2.616, year: 2016

Shear viscosity of liquid argon and liquid rubidium

International Nuclear Information System (INIS)

Chiakwelu, O.

1978-01-01

A direct evaluation of the shear viscosity coefficient for models of liquid rubidium and liquid argon is presented by neglecting the cross-terms in the autocorrelation function of the transverse component of the momentum stress tensor. The time dependence of the shear viscosity for liquid argon is found to display a long decaying tail in qualitative agreement with a computer calculation of Levesque et al. However, the numerical values of the shear viscosity coefficients are smaller than the experimentally determined values of about 45% for liquid rubidium and 35% for liquid argon

Observations on the Reliability of Rubidium Frequency Standards on Block 2/2A GPS Satellites

Science.gov (United States)

Dieter, Gary L.

1996-01-01

Currently, the block 2/2A Global Positioning System (GPS) satellites are equipped with two rubidium frequency standards. These frequency standards were originally intended to serve as the back-ups to two cesium frequency standards. As the constellation ages, the master Control Station is forced to initialize and increasing number or rubidium frequency standards. Unfortunately the operational use of these frequency standards has not lived up to initial expectations. Although the performance of these rubidium frequency standards has met and even exceeded GPS requirements, their reliability has not. The number of unscheduled outage times and the short operational lifetimes of the rubidium frequency standards compare poorly to the track record of the cesium frequency standards. Only a small number of rubidium frequency standards have actually been made operational. Of these, a large percentage have exhibited poor reliability. If this trend continues, it is unlikely that the rubidium frequency standards will help contribute to the navigation payload meeting program specification.

Erratum to: Selective Bioaccumulation of Rubidium by Microalgae from Industrial Wastewater Containing Rubidium and Lithium.

Czech Academy of Sciences Publication Activity Database

Kaštánek, P.; Kronusová, O.; Kaštánek, František; Brányiková, Irena; Prochazková, G.; Jandová, J.; Brányik, T.; Bišová, Kateřina

2018-01-01

Roč. 30, č. 1 (2018), s. 469 ISSN 0921-8971 Institutional support: RVO:67985858 ; RVO:61388971 Keywords : rubidium * lithium * microalgae Subject RIV: CI - Industrial Chemistry, Chemical Engineering; EE - Microbiology, Virology (MBU-M) OBOR OECD: Chemical process engineering; Microbiology (MBU-M) Impact factor: 2.616, year: 2016

Rubidium in the food chain

Energy Technology Data Exchange (ETDEWEB)

Anke, M. [Inst. of Nutrition and Environment, Friedrich Schiller Univ., Jena (Germany); Angelow, L. [Inst. of Nutrition and Environment, Friedrich Schiller Univ., Jena (Germany)

1995-05-01

In spite of its abundant occurrence in the earth`s crust (310 mg Rb/kg) and its composition of a stable (72.2%) and a radioactive (27.8%) isotope, rubidium (Rb) belongs to the forgotten ultratrace elements. The interest in this ultratrace element grew considerably after Rb deficiency experiments with goats had shown that their growth was depressed, that > 80% of them aborted their kids. The geological origin of the site takes significant effect on the Rb content of the flora. Granite and gneiss weathering soils produce the by far Rb-richest plant populations, and drinking water. The water of the gneiss sites contained 18 {mu}g Rb/l, that of diluvial sands 3 {mu}g/l. Herbivores store most Rb whereas carnivores and omnivores accumulate significantly less Rb. The analysis of 137 foodstuffs and beverages in 15-fold repetition showed that the starch- and sugar-rich cereals, pasta, bread and confectionary are poor in Rb (1 mg/kg dry mater (DM)). Fruit and vegetables accumulate between 5 and > 60 mg Rb/kg (asparagus). Boiling drastically reduces the Rb content of vegetables. Animal foodstuffs are relatively poor in Rb. Poultry meat as well as freshwater fish are relatively rich in Rb. Coffee (40 mg/kg DM) and black tea (100 mg Rb/kg DM) store much Rb, 85% of which pass into the beverage. (orig.)

Strontium-82/rubidium-82 generator

International Nuclear Information System (INIS)

Gennaro, G.P.; Haney, P.S.

1986-01-01

Hydroxylapatite, a compound having the formula: M 10 (PO 4 ) 6 (OH) 2 wherein M is calcium, strontium, barium, lead, iron, sodium, potassium, zinc, cadmium, magnesium, aluminium or a rare earth metal, is provided as a support medium for strontium-82 in a strontium-82/rubidium-82 parent-daughter radionuclide generator

Spontaneuos and Parametric Processes in Warm Rubidium Vapours

Directory of Open Access Journals (Sweden)

Dąbrowski M.

2014-12-01

Full Text Available Warm rubidium vapours are known to be a versatile medium for a variety of experiments in atomic physics and quantum optics. Here we present experimental results on producing the frequency converted light for quantum applications based on spontaneous and stimulated processes in rubidium vapours. In particular, we study the efficiency of spontaneously initiated stimulated Raman scattering in the Λ-level configuration and conditions of generating the coherent blue light assisted by multi-photon transitions in the diamond-level configuration. Our results will be helpful in search for new types of interfaces between light and atomic quantum memories.

Non-selective photoionization of Rubidium

International Nuclear Information System (INIS)

1987-01-01

Effusive atomic beam of Rubidium have been generated through an effusive source. An oriel uv-light source was focused to irradiate and interact with atomic beam of Rb. The energy of the uv-lamp was enough to raise the Rb atom by 4.17 eV to the ionization continuum level of Rb

Precision flow-controlled rubidium-82 generator for bolus and constant infusion studies

International Nuclear Information System (INIS)

Yano, Y.

1981-01-01

A unique flow rate controller and large reservoir pumping system have been developed for infusing rubidium-82 intravenously at bolus, constant, or variable infusion rates. Using rubidium-82 and the positron ring detector tomograph, extraction or flow information can be obtained in studies of the heart, head, or kidneys

The Kinetics of Ouabain Inhibition and the Partition of Rubidium Influx in Human Red Blood Cells

Science.gov (United States)

Beauge, L. A.; Adragna, Norma

1971-01-01

In the development of ouabain inhibition of rubidium influx in human red blood cells a time lag can be detected which is a function of at least three variables: the concentrations of external sodium, rubidium, and ouabain. The inhibition is antagonized by rubidium and favored by sodium. Similar considerations could be applied to the binding of ouabain to membrane sites. The total influx of rubidium as a function of external rubidium concentration can be separated into two components: (a) a linear uptake not affected by external sodium or ouabain and not requiring an energy supply, and (b) a saturable component. The latter component, on the basis of the different effects of the aforementioned factors, can be divided into three fractions. The first is ouabain-sensitive, inhibited by external sodium at low rubidium, and requires an energy supply; this represents about 70–80% of the total uptake and is related to the active sodium extrusion mechanism. The second is ouabain-insensitive, activated by external sodium over the entire range of rubidium concentrations studied, and dependent on internal ATP; this represents about 15% of the total influx; it could be coupled to an active sodium extrusion or belong to a rubidium-potassium exchange. The third, which can be called residual influx, is ouabain-insensitive, unaffected by external sodium, and independent of internal ATP; this represents about 10–20% of the total influx. PMID:5553102

Positron scattering by rubidium and caesium

International Nuclear Information System (INIS)

Kernoghan, A.A.; Walters, H.R.J.; McAlinden, M.T.

1996-01-01

We report results in the energy range 0.5 to 64 eV for positron scattering by ground state rubidium and caesium in Ps(1s,2s,2p,3s,3p,3d) + Rb(5s,5p,6s,6p,4d) and Ps(1s,2s,2p,3s,3p,3d) + Cs(6s,6p,7s,7p,5d) coupled-state approximations, respectively. The pattern of results is similar to analogous calculations made on potassium by McAlinden et al. Except at the lowest energies, positronium formation is found to be almost entirely into excited states, with there being a dramatic collapse of the Ps(1s) cross section in the case of caesium. Ps(n = 2), Ps(n = 3) and Ps(n≥ 4) cross sections are predicted to be of comparable size. Ps(n≥ 4) formation is estimated from the calculated Ps(n = 3) results using the n 3 scaling rule. Good agreement in shape and magnitude is obtained with the recent lower bound measurements of total positronium formation in rubidium by Surdutovich et al, although there are differences in detail. Good agreement is also achieved with the total cross section measurements of Parikh et al on rubidium after these have been corrected for discrimination against forward elastic scattering and renormalized upwards by 5%. These total cross section measurements display a pronounced peak near 6 eV which is well reproduced by the present theory but is at variance with the earlier Rb(5s,5p,6s,6p,4d) calculations of McEachran et al which neglect positronium formation. This peak, which also appears in the calculations on potassium and caesium, is primarily associated with the maximum in the total positronium formation cross section. At low energies elastic scattering is dominant, this dominance being directly taken over by the resonance excitation of the atom with increasing impact energy. The next most important cross section is positronium formation, followed by excitation of the lowest atomic d-state. The 5s → 6s and 5s → 6p transitions in rubidium and the 6s → 7s and 6s → 7p transitions in caesium are of relatively minor importance. (Author)

Excitation of higher lying energy states in a rubidium DPAL

Science.gov (United States)

Wallerstein, A. J.; Perram, Glen; Rice, Christopher A.

2018-02-01

The spontaneous emission in a cw rubidium diode dumped alkali laser (DPAL) system was analyzed. The fluorescence from higher lying states decreases with additional buffer gas. The intermediate states (7S, 6P, 5D) decay more slowly with buffer gas and scale super-linearly with alkali density. A detailed kinetic model has been constructed, where the dominant mechanisms are energy pooling and single photon ionization. It also includes pumping into the non-Lorentzian wings of absorption profiles, fine structure mixing, collisional de-excitation, and Penning ionization. Effects of ionization in a high powered CW rubidium DPAL were assessed.

Interlaboratory determinations of isotopically enriched metals by field desorption mass spectroscopy

International Nuclear Information System (INIS)

Bahr, U.; Schulten, H.R.; Achenbach, C.; Ziskoven, R.

1982-01-01

The isotopic distribution of stable isotopes in six enriched metals (calcium, copper, barium, rubidium, strontium and thallium) has been determined by field desorption mass spectrometry. A first evaluation of the interlaboratory reproducibility of the application of this method for trace determination of metals was made using three different types of mass spectrometers in three different laboratories. The standard deviations for the most abundant isotopes of the metals investigated are between +-0.1 and +-0.5%. Within these standard deviations, the values obtained by the three mass spectrometry groups are the same. To support the accuracy of our quantification, thermal ionization mass spectrometry has been employed and confirms the results of the field desorption method. (orig.) [de

Double sodium rubidium molybdates

International Nuclear Information System (INIS)

Mokhoseev, M.V.; Khal'baeva, K.M.; Khajkina, E.G.; Ogurtsov, A.M.

1990-01-01

According to ceramic technique double sodium-rubidium molybdates of the compositions Rb 2-x Na x MoO 4 (0.5≤x≤0.67) and Na 3 Rb(MoO 4 ) 2 have been prepared. It is ascertained that Rb 2-x Na x MoO 4 is crystallized in glaserite structural type (trigonal crystal system, sp.gr. P3m1, Z=2) and melts incongruently at 640 deg C. Na 3 Rb(MoO 4 ) 2 at room temperature is unstable and gradually decomposes into Na 2 MoO 4 and Rb 2-x Na x MoO 4

Rubidium selenatoindiates

International Nuclear Information System (INIS)

Kadoshnikova, N.V.; Dejchman, Eh.N.; Tananaev, I.V.

1977-01-01

Interaction of aqueous solutions of indium and rubidium selenates at 20 deg C has been investigated. From the experimental data obtained in studying solubility in the Rb 2 SeO 4 -In 2 (SeO 4 ) 3 -H 2 O system it follows that at n=[Rb 2 SeO 4 ]/[In 2 SeO 4 ) 3 ]( 4 ) 2 x4H 2 O is formed. The optimum conditions for obtaining this product are solutions with n=3-5 at increased acidity (approximately 5%H 2 SeO 4 ). RbIn(SeO 4 ) 2 x4H 2 O consists of negative biaxial crystals. Dehydration occurs in a single stage. The substance obtained is hydrolized in excess Rb 2 SO 4 with the formation of basic salts of variable composition. RbIn(SeO 4 ) 2 x4H 2 O has been investigated crystal-optically, thermographically, and roentgenographically

A gravimetric and an X-ray fluorescence method for the determination of rubidium in Rb2U(SO4)3

International Nuclear Information System (INIS)

Mudher, K.D.S.; Krishnan, K.; Jayadevan, N.C.

1993-01-01

Chemical characterization of rubidium uranium(IV) trisulfate, RB 2 U(SO 4 ) 3 , a new chemical assay standard for uranium requires accurate analysis of rubidium. A gravimetric and an X-ray fluorescence method (XRF) for the determination of rubidium in this compound are described. In the gravimetric method, rubidium is determined as Rb 2 Na[Co(NO 2 ) 6 ].H 2 O without separating uranium with a precision of the order of ±0.5%. In the XRF method, the concentration ratio of rubidium to uranium, C Rb /C U , is determined in the solid samples by the binary ratio method using calibration between intensity ratios (I Rb /I U ) and concentration ratios (C Rb /C U ). (author) 6 refs.; 2 figs.; 3 tabs

Theoretical study of non reactive collisions between alkaline atoms and hydrogen or deuterium molecules. Calculations and analysis of the potential surfaces. Application to the fine structure transitions of the Rubidium

International Nuclear Information System (INIS)

Rossi, F.N.

1986-10-01

The adiabatic potential lines are first obtained through the use of a pseudo-potential, depending on the electronic orbital moment. A perturbative method is then used to generate the potential surfaces, according to the potential lines. A quantum calculation in the thermal energy domain is realized, for the cross-sections concerning the structure transitions of the Rubidium, induced by the collision with hydrogen or deuterium molecules. This allowed the interpretation of the experimentally observed isotopic effect [fr

Mineralogy of the fraction and age estimation rubidium - strontium of the Bambui Group, MG, Brazil

International Nuclear Information System (INIS)

Bonhomme, M.G.

1976-01-01

A study of the illite crystallinity of sediments of the Upper Precambrian Bambui Group, MG, has been done to determine the zones without metamorphism, the only ones able to give the age of the sedimentation. Only the region of Januaria escaped from any sensible thermo-tectonic event. The Bambui sediments contain well crystallized vermiculite probably formed during the anchimetamorphism. The rubidium-strontium age obtained in Januaria (619 + - 17 m.y.) corresponds in fact to the main phase of the Brazilian orogenic cycle. The late isotopic homogeneization was caused by a strong late diagenesis. The anchimetamorphic phosphateous sediments in Cedro do Abate show that the ferro-magnesian illite is a more easely open system than aluminous illite, and in this case dates the later event of the Brazilian cycle at 445 + - 25 m.y. The age of 600 m.y. for the metamorphism is a younger limit for the real age of the Bambui, the late Precambrian age of which is confirmed

Vanadium, rubidium and potassium in Octopus vulgaris (Mollusca: Cephalopoda

Directory of Open Access Journals (Sweden)

Sónia Seixas

2005-06-01

Full Text Available The levels of vanadium, rubidium and potassium were determined in Octopus vulgaris caught during commercial fishing activities at three locations (Cascais, Santa Luzia and Viana do Castelo in Portugal in autumn and spring. We determined the concentration of these elements in digestive gland, branchial heart, gills, mantle and arms in males and females. At least five males and five females were assessed for each season/location combination. Elemental concentrations were determined by Particle Induced X-ray Emission (PIXE. Vanadium was detectable only in digestive gland and branchial heart samples. Its concentration was not correlated with total weight, total length or mantle length. There were no differences in concentrations of V, Rb and K between sexes. There were significant differences in vanadium concentrations in branchial hearts in autumn between samples from Viana do Castelo and those from the other two sites. We found a significant positive relationship between the concentration of vanadium and those of potassium and rubidium in branchial hearts. Branchial hearts appear to play an important role in decontamination of V.

Short-lived radionuclide production capability at the Brookhaven Linac Isotope Producer

International Nuclear Information System (INIS)

Mausner, L.F.; Richards, P.

1985-01-01

The Brookhaven National Linac Isotope Producer is the first facility to demonstrate the capability of a large linear accelerator for efficient and economical production of difficult-to-make, medically useful radionuclides. The linac provides a beam of 200-MeV protons at an integrated beam current of up to 60 μA. The 200-MeV proton energy is very suitable for isotope production because the spallation process can create radionuclides unavailable at lower energy accelerators or reactors. Several medically important short-lived radionuclides are presently being prepared for on-site and off-site collaborative research programs. These are iodine-123, iron-52, manganese-52m, ruthenium-97, and the rubidium-81-krypton-81m system. The production parameters for these are summarized

Rubidium dimers in paraffin-coated cells

International Nuclear Information System (INIS)

Acosta, V M; Windes, D; Corsini, E; Ledbetter, M P; Karaulanov, T; Budker, D; Jarmola, A; Auzinsh, M; Rangwala, S A; Jackson Kimball, D F

2010-01-01

Measurements were made to determine the density of rubidium dimer vapor in paraffin-coated cells. The number density of dimers and atoms in similar paraffin-coated and uncoated cells was measured by optical spectroscopy. Due to the relatively low melting point of paraffin, a limited temperature range of 43-80 0 C was explored, with the lower end corresponding to a dimer density of less than 10 7 cm -3 . With 1 min integration time, a sensitivity to dimer number density of better than 10 6 cm -3 was achieved. No significant difference in dimer density between the cells was observed.

Concentration differences between serum and plasma of the elements cobalt, iron, mercury, rubidium, selenium and zinc determined by neutron activation analysis

International Nuclear Information System (INIS)

Kasperek, K.; Kiem, J.; Iyengar, G.V.; Feinendegen, L.E.

1981-01-01

The differences in concentrations of cesium, cobalt, iron, mercury, rubidium, selenium and zinc between serum and plasma were examined with the aid of instrumental neutron activation analysis. Eighty serum and plasma samples obtained from 13 donors were compared. Serum was prepared in plastic tubes immediately after clotting, and plasma was separated with heparin as anticoagulant. No significant differences in the concentrations of cesium, cobalt, mercury and selenium were observed. However, the concentrations of iron, rubidium and zinc were significantly higher in serum than in plasma. The average differences were 322, 12 and 20 ng/ml for iron, rubidium and zinc, respectively. The average differences found for cesium, rubidium and zinc were far below that which can be expected from a complete, or considerable release of these elements from platelets which aggregate or disintegrate during the clotting process in preparing serum. (orig.)

Isotopes and ages in the northern Peninsular Ranges batholith, southern California

Science.gov (United States)

Kistler, Ronald W.; Wooden, Joseph L.; Morton, Douglas M.

2003-01-01

Strontium, oxygen and lead isotopic and rubidium-strontium geochronologic studies have been completed on Cretaceous and Jurassic (?) granitic rock samples from the northern Peninsular Ranges batholith in southern California. Many of these samples were collected systematically and studied chemically by A. K. Baird and colleagues (Baird and others, 1979). The distribution of these granitic rocks is shown in the Santa Ana, Perris, and San Jacinto Blocks, bounded by the Malibu Coast-Cucamonga, Banning, and San Andreas fault zones, and the Pacific Ocean on the map of the Peninsular Ranges batholith and surrounding area, southern California. The granitic rock names are by Baird and Miesch (1984) who used a modal mineral classification that Bateman and others (1963) used for granitic rocks in the Sierra Nevada batholith. In this classification, granitic rocks have at least 10% quartz. Boundaries between rock types are in terms of the ratio of alkali-feldspar to total feldspar: quartz diorite, 0-10%; granodiorite, 10-35%; quartz monzonite 35-65%; granite >65%. Gabbros have 0-10% quartz. Data for samples investigated are giv in three tables: samples, longitude, latitude, specific gravity and rock type (Table 1); rubidium and strontium data for granitic rocks of the northern Peninsular Ranges batholith, southern California (Table 2); U, Th, Pb concentrations, Pb and Sr initial isotopic compositions, and δ18O permil values for granitic rocks of the northern Peninsular Ranges batholith (table 3).

The determination of initial ratio of strontium isotope in rocks and its geological application

International Nuclear Information System (INIS)

Ying Junlong; Zhao Puyun; Lin Xiulan

1989-04-01

The method to determine the initial ratio of strontium isotopes existed in rocks of poor rubidium and rich strontium and main carrier minerals is introduced. The initial ratio obtained from this method is equivalent to that acquired by Rb-Sr isochrone. Based on this result, information on regional rock genesis and mineralization regularities can be provided. It has great significance in the research on activities of ancient continental margin and material sources as well as their evolution. The migration of rock, and ore-forming materials, matallogenetic mechanism and its distribution in the space and time evolution are studied by using these data. In conclusion, the determination of strontium isotopes has broad prospects in the geological research

Geochemical and isotopic characteristics and magma sources of the early Cretaceous trachybasalts of the Goby-Altai rift zone: an example of grabens in the Arts-Bogdo range

International Nuclear Information System (INIS)

Samojlov, V.S.; Yarmolyuk, V.V.; Kovalenko, V.I.; Ivanov, V.G.; Pakhol'chenko, Yu.A.

1998-01-01

Geochemical and isotopic-geochemical characteristics of the basalts of Early Cretaceous (Hoby-Altai rift zone; Arts-Bogdo region, Mongolia). Atomic absorption spectroscopy, X-ray fluorescence spectroscopy, photometry, mass spectroscopy and other methods were used. Mantle nature of the basalt geochemical specificity is shown as well as their initial melts. Data on the rubidium-strontium isotopic composition of Neocomian basalts are the following ones: 87 Sr/ 86 Sr 87 Sr/ 86 Sr > 0.707 and Rb/Sr > 0.06 [ru

A novel procedure for Rubidium separation and its isotope measurements on geological samples by MC-ICP-MS

Science.gov (United States)

Ma, J.; Zhang, Z.; Wei, G.; Zhang, L.

2017-12-01

A method including a novel column Rb separation procedure and high-precision Rb isotope measurement in geological materials by using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in standard-sample-bracketing (SSB) mode has been developed. Sr-Spec resin was employed, in which the distribution coefficients for Rb, K, Ba and Sr are different in nitric acid, to sequentially separate them from the matrix. The dissolved samples were loaded on the column in 3 M HNO3, the main matrix such as Al, Ca, Fe, Mg, Mn and Na were removed by rinsing with 4.5 mL HNO3, Rb and K were then sequentially eluted by 3 M HNO3 in different volumes. After that, Ba was eluted by 8 M HNO3, and Sr was finally eluted by Milli-Q water. This enable us to collect the pure Rb, K, Ba and Sr one by one with recovery close to 100% for their isotopic compositions measurement on MC-ICP-MS. We here focus on Rb isotope measurement. The measurement using MC-ICP-MS yielded an internal precision for δ87Rb of external precision was generally better than ± 0.06‰ (2SD) based on the long-term results of the Rb standard solutions NIST SRM 984. A series of geological rock standards, were analyzed using this method, and the results indicate significant Rb isotope differences in different geologic materials. This will provide a powerful tool to investigate Rb isotope fractionation during geological processes.Based on this method, Rb isotope compositions from a basaltic weathering profile were carried out. The data show the lighter Rb (85Rb) isotope is preferentially leached from the weathering profile and remains heavy Rb isotope (87Rb) in the weathered residues during the incipient weathering stage. From the moderate to advanced weathering stage, the significant variations of Rb isotope were observed and multiple factors, such as leaching, adsorption, desorption, and precipitation, should play important role in fractionating Rb isotope.

Early risk stratification using Rubidium-82 positron emission tomography in STEMI patients

DEFF Research Database (Denmark)

Ghotbi, Adam Ali; Hasbak, Philip; Nepper-Christensen, Lars

2018-01-01

BACKGROUND: Assessment of infarct size after myocardial infarction is predictive of subsequent morphological changes and clinical outcome. This study aimed to assess subacute post-intervention Rubidium-82 ((82)Rb)-PET imaging in predicting left ventricle ejection fraction, regional wall motion, a...

Silver diffusion and isotope effect in silver rubidium iodide

International Nuclear Information System (INIS)

Arzigian, J.S.

1980-01-01

The diffusion coefficient of silver in RbAg 4 I 5 was measured in both superionic phases using radiotracer Ag-110m and serial sectioning with a low temperature sectioning apparatus. The activation energies for diffusion in alpha-RbAg 4 I 5 and beta-RbAg 4 I 5 , respectively, are 0.11 +- 0.01 eV and 0.20 +- 0.04 eV. An isotope effect for diffusion was also measured in both superionic phases. Ag-105 and Ag-110m radioisotopes were used with gamma spectroscopy and energy discrimination. The effect is small, with no significant temperature variation, with the value at 333 0 K being 0.12 +- 0.01. The second-order phase transition at 208 0 K has a small effect, if any, on the magnitude of the effect. The data suggest that a highly cooperative transport mechanism is responsible for the unusually high values of both the conductivity and diffusion coefficient. Although it is not possible to deduce the particular mechanism involved, theories inolving ionic polarons, or cooperative motion, such as crowdions or solitons, seem consistent with the observed results

Radiogenic Isotopes in Weathering and Hydrology

Science.gov (United States)

Blum, J. D.; Erel, Y.

2003-12-01

as on the observation that radiogenic isotopes are sometimes preferentially released compared to nonradiogenic isotopes of the same element during acid leaching of rocks ( Hart and Tilton, 1966; Silver et al., 1984; Erel et al., 1991). A major finding of these investigations was that weathering often results in anomalously young Rb-Sr isochron ages, and discordant Pb-Pb ages. Rubidium is generally retained relative to strontium in whole-rock samples, and in some cases radiogenic strontium and lead are lost preferentially to common strontium and lead from weathered minerals.The most widely utilized of these isotopic systems is Rb-Sr, followed by U-Pb. The K-Ar system is not directly applicable to most studies of rock-water interaction, because argon is a noble gas, and upon release during mineral weathering mixes with atmospheric argon, limiting its usefulness as a tracer in most weathering applications. Argon and other noble gas isotopes have, however, found important applications in hydrology (see Chapter 5.15). Three other isotopic systems commonly used in geochronology and petrology include Sm-Nd, Lu-Hf, and Re-Os. These parent and daughter elements are in very low abundance and concentrated in trace mineral phases. Sm-Nd, Lu-Hf, and Re-Os have been used in a few weathering studies but have not been utilized extensively in investigations of weathering and hydrology.The decay of 87Rb to 87Sr has a half-life of 48.8 Gyr, and this radioactive decay results in natural variability in the 87Sr/86Sr ratio in rubidium-bearing minerals (e.g., Blum, 1995). The trace elements rubidium and strontium are geochemically similar to the major elements potassium and calcium, respectively. Therefore, minerals with high K/Ca ratios develop high 87Sr/86Sr ratios over geologic timescales. Once released into the hydrosphere, strontium retains its isotopic composition without significant fractionation by geochemical or biological processes, and is therefore a good tracer for sources and

The determination of cesium and rubidium in highly radioactive waste liquid

International Nuclear Information System (INIS)

Wei Songsheng

1991-01-01

Cesium and rubidium in high-level waste liquid were determined by atomic absorption spectrometry with the instrument modified for analyzing radioactive samples. The results show that the method is effective and safe. The error of the method is less than +- 3%, and it has been used in the production of cesium

Thermodynamic properties of molten mixtures of lithium, rubidium, cesium and beryllium chlorides

International Nuclear Information System (INIS)

Zarubitskij, O.G.; Podafa, B.P.; Dubovoj, P.G.

1982-01-01

e. m. f. in binary systems of beryllium chloride with rubidium and cesium chlorides were measured. Concentration dependences of thermodynamic functions (mixing entropy Gibbs free energy) of beryllium chloride in the systems as well as with the participation of lithium chloride were analysed

Study on the application of crown ether for neutron activation analysis of rubidium and rhenium in rock samples

International Nuclear Information System (INIS)

Wang Xiaolin; Fu Yibei; Liu Yinong; Xiong Zonghua; Hao Fanhua

1996-01-01

The extraction behaviour of rubidium and rhenium with 18-crown-6 (18C6) and benzo-15-crown-5 (B15C5) in nitrobenzene from picric acid or potassium hydroxide solution are studied and methods for separation and determination are developed. The molar ratio of 18C6 to Rb and B15C5 to Re in the extracted species is probably 2:1. Rubidium and rhenium in rock samples are satisfactorily determined by neutron activation method

Fourier transform infrared emission spectra of atomic rubidium: g- and h-states

Czech Academy of Sciences Publication Activity Database

Civiš, Svatopluk; Ferus, Martin; Kubelík, Petr; Chernov, Vladislav E.; Zanozina, Ekaterina M.

2012-01-01

Roč. 45, č. 17 (2012), s. 175002 ISSN 0953-4075 R&D Projects: GA AV ČR IAAX00100903 Institutional support: RVO:61388955 Keywords : Fourier transform infrared emission spectra * atomic rubidium * physical chemistry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.031, year: 2012

High-flux cold rubidium atomic beam for strongly-coupled cavity QED

Energy Technology Data Exchange (ETDEWEB)

Roy, Basudev [Indian Institute of Science Education and Research, Kolkata (India); University of Maryland, MD (United States); Scholten, Michael [University of Maryland, MD (United States)

2012-08-15

This paper presents a setup capable of producing a high-flux continuous beam of cold rubidium atoms for cavity quantum electrodynamics experiments in the region of strong coupling. A 2D{sup +} magneto-optical trap (MOT), loaded with rubidium getters in a dry-film-coated vapor cell, fed a secondary moving-molasses MOT (MM-MOT) at a rate greater than 2 x 10{sup 10} atoms/s. The MM-MOT provided a continuous beam with a tunable velocity. This beam was then directed through the waist of a cavity with a length of 280 μm, resulting in a vacuum Rabi splitting of more than ±10 MHz. The presence of a sufficient number of atoms in the cavity mode also enabled splitting in the polarization perpendicular to the input. The cavity was in the strong coupling region, with an atom-photon dipole coupling coefficient g of 7 MHz, a cavity mode decay rate κ of 3 MHz, and a spontaneous emission decay rate γ of 6 MHz.

Dual cesium and rubidium atomic fountain with a 10-16 level accuracy and applications

International Nuclear Information System (INIS)

Chapelet, F.

2008-05-01

Atomic fountains are the most accomplished development of the atomic clocks based on the cesium atom whose hyperfine resonance defines the SI second since 1967. Today these systems are among those which realize the second with the best accuracy. We present the last developments of the cold cesium and rubidium atom dual fountain experiment at LNE-SYRTE. This unique dual setup would allow to obtain an outstanding resolution in fundamental physics tests based on atomic transition frequency comparisons. In order to enable operation with both atomic species simultaneously, we designed, tested and implemented on the fountain new collimators which combine the laser lights corresponding to each atom. By comparing our rubidium fountain to another cesium fountain over a decade, we performed a test of the stability of the fine structure constant at the level of 5 * 10 -16 per year. We carried on the work on the clock accuracy and we focused on the phase gradients effects in the interrogation cavity and on the microwave leakage. The fountain accuracy has been evaluated to 4 * 10 -16 for the cesium clock and to 5 * 10 -16 for the refurbished rubidium clock. As a powerful instrument of metrology, our fountain was implicated in many clock comparisons and contributed many times to calibrate the International Atomic Time. Furthermore, we used the fountain to perform a new test of Lorentz local invariance. (author)

Analyses of absorption distribution of a rubidium cell side-pumped by a Laser-Diode-Array (LDA)

Science.gov (United States)

Yu, Hang; Han, Juhong; Rong, Kepeng; Wang, Shunyan; Cai, He; An, Guofei; Zhang, Wei; Yu, Qiang; Wu, Peng; Wang, Hongyuan; Wang, You

2018-01-01

A diode-pumped alkali laser (DPAL) has been regarded as one of the most potential candidates to achieve high power performances of next generation. In this paper, we investigate the physical properties of a rubidium cell side-pumped by a Laser-Diode-Array (LDA) in this study. As the saturated concentration of a gain medium inside a vapor cell is extremely sensitive to the temperature, the populations of every energy-level of the atomic alkali are strongly relying on the vapor temperature. Thus, the absorption characteristics of a DPAL are mainly dominated by the temperature distribution. In this paper, the temperature, absorption, and lasing distributions in the cross-section of a rubidium cell side-pumped by a LDA are obtained by means of a complicated mathematic procedure. Based on the original end-pumped mode we constructed before, a novel one-direction side-pumped theoretical mode has been established to explore the distribution properties in the transverse section of a rubidium vapor cell by combining the procedures of heat transfer and laser kinetics together. It has been thought the results might be helpful for design of a side-pumped configuration in a high-powered DPAL.

Pre-Excitation Studies for Rubidium-Plasma Generation

CERN Document Server

Aladi, M; Barna, I.F.; Czitrovszky, Aladar; Djotyan, Gagik; Dombi, Peter; Dzsotjan, David; FöLdes, Istvan; Hamar, Gergo; Ignacz, Peter; Kedves, Miklos; Kerekes, Attila; Levai, Peter; Marton, Istvan; Nagy, Attila; Oszetzky, Daniel; Pocsai, Mihaly; Racz, Peter; Raczkevi, Bela; Szigeti, Janos; Sörlei, Zsuzsa; Szipöcs, Robert; Varga, Dezso; Varga-Umbrich, Karoly; Varro, Sandor; Vamos, Lenard; Vesztergombi, György

2014-01-01

The key element in the Proton-Driven-Plasma-Wake-Field-Accelerator (AWAKE) project is the generation of highly uniform plasma from Rubidium vapor. The standard way to achieve full ionization is to use high power laser which can assure the over-barrier-ionization (OBI) along the 10 meters long active region. The Wigner-team in Budapest is investigating an alternative way of uniform plasma generation. The proposed Resonance Enhanced Multi Photon Ionization (REMPI) scheme probably can be realized by much less laser power. In the following the resonant pre-excitations of the Rb atoms are investigated, theoretically and the status report about the preparatory work on the experiment are presented.

Determination of the Rb atomic number density in dense rubidium vapors by absorption measurements of Rb2 triplet bands

International Nuclear Information System (INIS)

Horvatic, Vlasta; Veza, Damir; Niemax, Kay; Vadla, Cedomil

2008-01-01

A simple and accurate way of determining atom number densities in dense rubidium vapors is presented. The method relies on the experimental finding that the reduced absorption coefficients of the Rb triplet satellite bands between 740 nm and 750 nm and the triplet diffuse band between 600 nm and 610 nm are not temperature dependent in the range between 600 K and 800 K. Therefore, the absolute values of the reduced absorption coefficients of these molecular bands can provide accurate information about atomic number density of the vapor. The rubidium absorption spectrum was measured by spatially resolved white-light absorption in overheated rubidium vapor generated in a heat pipe oven. The absolute values for the reduced absorption coefficients of the triplet bands were determined at lower vapor densities, by using an accurate expression for the reduced absorption coefficient in the quasistatic wing of the Rb D1 line, and measured triplet satellite bands to the resonance wing optical depth ratio. These triplet satellite band data were used to calibrate in absolute scale the reduced absorption coefficients of the triplet diffuse band at higher temperatures. The obtained values for the reduced absorption coefficient of these Rb molecular features can be used for accurate determination of rubidium atomic number densities in the range from about 5 x 10 16 cm -3 to 1 x 10 18 cm -3

Isotopic Characteristics and Age Dating of the Pumice in Okinawa Trough

Institute of Scientific and Technical Information of China (English)

陈丽蓉; 翟世奎; 申顺喜

1994-01-01

The data on the isotope compositions of rubidium,strontium and oxygen in the pumice ofOkinawa Trough are reported for the first time.The ages of the pumice were successfully dated with themethod of U-series disequilibrium.Then,the material source,crystallization evolution of magma and activi-ty cycles of volcanos are explored.Isotopic data show that pumice magma was originally from the mantle,but had undergone a full crystal-lization differentiation and had been contaminated to a fair extent by crust-derived materials before the mag-ma was erupted out of the sea floor.According to the dating results available so far,the earliest volcaniceruption in Okinawa Trough occurred about 70,000 a ago and the latest eruption was about 10,000 a B.P.During this period,there were three volcanic eruption cycles which were respectively corresponding to themiddle Late Pleistocene,the late Late Pleistocene and the Early Holocene.

X-ray and neutron diffraction and molecular dynamics simulation of molten lithium and rubidium nitrates

International Nuclear Information System (INIS)

Yamaguchi, Toshio; Okada, Isao; Ohtaki, Hitoshi; Mikami, Masuhiro; Kawamura, Kazutaka

1986-01-01

Molecular dynamics simulations have been performed for lithium and rubidium nitrate melts at 550 and 600K, respectively, together with X-ray and neutron diffraction experiments. Simple Coulomb pair potentials with Born-type repulsions have been adopted in the simulations with a rigid body model for the nitrate ion. Structure functions derived from the X-ray and neutron experiments are well reproduced by the simulations, from which the three-dimensional cation distribution around the nitrate ion has been revealed. The self-diffusion coefficients, the velocity autocorrelation functions and the self-exchange velocities of lithium, rubidium and nitrate ions have been calculated. Anisotropic motion of nitrate ions has been found and is discussed on the basis of the structure of the melts. (author)

Dual cesium and rubidium atomic fountain with a 10{sup -16} level accuracy and applications; Fontaine atomique double de cesium et de rubidium avec une exactitude de quelques 10{sup -16} et applications

Energy Technology Data Exchange (ETDEWEB)

Chapelet, F

2008-05-15

Atomic fountains are the most accomplished development of the atomic clocks based on the cesium atom whose hyperfine resonance defines the SI second since 1967. Today these systems are among those which realize the second with the best accuracy. We present the last developments of the cold cesium and rubidium atom dual fountain experiment at LNE-SYRTE. This unique dual setup would allow to obtain an outstanding resolution in fundamental physics tests based on atomic transition frequency comparisons. In order to enable operation with both atomic species simultaneously, we designed, tested and implemented on the fountain new collimators which combine the laser lights corresponding to each atom. By comparing our rubidium fountain to another cesium fountain over a decade, we performed a test of the stability of the fine structure constant at the level of 5 * 10{sup -16} per year. We carried on the work on the clock accuracy and we focused on the phase gradients effects in the interrogation cavity and on the microwave leakage. The fountain accuracy has been evaluated to 4 * 10{sup -16} for the cesium clock and to 5 * 10{sup -16} for the refurbished rubidium clock. As a powerful instrument of metrology, our fountain was implicated in many clock comparisons and contributed many times to calibrate the International Atomic Time. Furthermore, we used the fountain to perform a new test of Lorentz local invariance. (author)

Labeling Feral Spruce Budworm (Lepidoptera: Tortricidae) Populations With Rubidium.

Science.gov (United States)

MacKinnon, Wayne; Eveleigh, Eldon; Silk, Peter; Forbes, Glen

2016-04-01

Rubidium (Rb) is a trace element that occurs naturally in low concentrations and is easily absorbed by plants, making it a useful tool for labeling insect defoliators, such as spruce budworm (Choristoneura fumiferana Clemens). Balsam fir trees (Abies balsamea (L.) Miller) injected with either 8 or 16 g per tree of rubidium chloride (RbCl) showed quick uptake and distribution throughout the crown, with no negative effects on tree shoot growth or spruce budworm survival and development. Adult spruce budworm that fed as larvae on trees injected with RbCl were clearly labeled, with significantly higher Rb concentrations than the background levels found in adults that fed as larvae on control trees. Rb concentrations in feral spruce budworm adults for both the 8 g (9 µg/g) and 16 g (25 µg/g) per tree treatments were at least five times lower than those in laboratory-reared adults on 1,000 µg/g RbCl diet (125 µg/g); survival, development, pupal weight, sex ratio, and mating status of spruce budworm were not adversely affected by Rb treatment. Egg masses laid by feral females that fed as larvae on Rb-labeled trees were also labeled with Rb. Injecting trees with RbCl is a viable technique for labeling feral spruce budworm populations to help distinguish local populations from immigrants to better evaluate the success of early intervention strategies such as mating disruption. © Crown copyright 2016.

Recent results of the pulsed optically pumped rubidium clock

Science.gov (United States)

Levi, F.; Micalizio, S.; Godone, A.; Calosso, C.; Bertacco, E.

2017-11-01

A laboratory prototype of a pulsed optically pumped (POP) clock based on a rubidium cell with buffer gas is described. This clock has shown very interesting physical and metrological features, such as negligible light-shift, strongly reduced cavity-pulling and very good frequency stability. In this regard, an Allan deviation of σy(τ) = 1.2 τ-1/2 for measurement times up to τ = 105 s has been measured. These results confirm the interesting perspectives of such a frequency standard and make it very attractive for several technological applications, such as radionavigation.

Optical potential study of electron scattering by rubidium

Energy Technology Data Exchange (ETDEWEB)

Chin, J. H.; Ratnavelu, K. [University of Malaya, Kuala Lumpur (Malaysia); Zhou, Y. [Harbin Institute of Technology, Harbin (China)

2011-10-15

The coupled-channel optical method (CCOM) has been implemented in a study of electronrubidium scattering. This method includes the continuum effect in the calculation via an ab-initio optical potential. Eight atomic states (5s, 5p, 4d, 6s, 6p, 5d, 7s, 7p) were used together with the continuum optical potential in the 5s-5s, 5s-5p, and 5p-5p coupling. The elastic, inelastic and total cross sections for electron-rubidium scattering at low and intermediate energies, ranging from 10 eV to 100 eV, are reported. The results are compared with available experimental and theoretical data.

Availability of enriched stable isotopes: present status and future prospects

International Nuclear Information System (INIS)

Hoff, R.W.

1986-01-01

The Electromagnetic Isotope Enrichment Facility (EMIEF) is currently used to produce 225 enriched stable isotopes of 50 elements. Among these are included most of the known elements with stable isotopes except for the noble gases, certain light elements, monisotopic elements, etc. The EMIEF can also be used to produce enriched samples of radioactive species, most notably the isotopes of uranium and plutonium. These enriched materials are placed in either the Sales Inventory of in the Research Materials Collection (RMC). The materials in the Sales Inventory are for sale to anyone on a first come, first served basis. Prices in the most recent catalog range from $0.05/mg for 99.8% 140 Ce to $1,267/mg for 98.5% 176 Lu. The materials in the RMC are made available to US researchers (or groups that include a US investigator) on a loan basis for use in non-destructive experiments and applications. In addition, certain samples have been provided to European investigators for cross-section studies through the auspices of EURATOM and the European-American Nuclear Data Committee. The status of the enriched isotopes included in the Sales Inventory is tabulated where isotopes are listed that are either not available or are in insufficient quantity or quality to meet current requests, as of 6/30/86. These can be summarized in the following subcategories: isotopes with zero inventory (22), Isotopes of insufficient quantity (17), and isotopes with insufficient enrichment quality (10). Of these 49 species, the supplies of 10 will be replenished by the scheduled FY86 enrichments in process (isotopes of bromine, calcium, nickel, potassium, rubidium, and strontium). In Table 3 are listed isotopes where the current inventory is less than the average annual sales level for the past five years. There are 47 isotopes listed, representing 25 different elements. Thus, there exists considerable potential for a substantial increase in the number of isotopes with zero inventory

A heated vapor cell unit for DAVLL in atomic rubidium

OpenAIRE

McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L.

2007-01-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 transitions in atomic rubidium is described. A 5 cm-long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field...

Studies on alterations of the 86-rubidium efflux from rat pancreatic islets caused by thiol and thiol oxidants

International Nuclear Information System (INIS)

Wahl, M.A.

1983-01-01

The following findings were revealed by this study: 1) Oxidation-reduction (redox) of the intracellular system of glutathione influences the potassium efflux by way of an increase in the 86-rubidium efflux brought about by the oxidation of intracellular thiols. 2) The 86-rubidium efflux is not subject to change by oxidation of extracellular thiols located in the membrane, nor can it in any way be influenced by reduced glutathione of exogenous origin. 3) The potassium efflux from rat pancreatic islets, being generally known to trigger the electric activities of the beta-cell, is controlled by the oxidation-reduction of intracellular thiols rather than by that of extracellular thiols. (TRV) [de

Laser pulse propagation in a meter scale rubidium vapor/plasma cell in AWAKE experiment

Energy Technology Data Exchange (ETDEWEB)

Joulaei, A. [Max-Planck Institute for Physics, Munich (Germany); University of Mazandaran (Iran, Islamic Republic of); Moody, J. [Max-Planck Institute for Physics, Munich (Germany); Berti, N.; Kasparian, J. [University of Geneva (Switzerland); Mirzanejhad, S. [University of Mazandaran (Iran, Islamic Republic of); Muggli, P. [Max-Planck Institute for Physics, Munich (Germany)

2016-09-01

We present the results of numerical studies of laser pulse propagating in a 3.5 cm Rb vapor cell in the linear dispersion regime by using a 1D model and a 2D code that has been modified for our special case. The 2D simulation finally aimed at finding laser beam parameters suitable to make the Rb vapor fully ionized to obtain a uniform, 10 m-long, at least 1 mm in radius plasma in the next step for the AWAKE experiment. - Highlights: • Discussion the AWAKE plasma source based on photoionization of rubidium vapor with a TW/cm^2 Intensity laser with a spectrum across valence ground state transition resonances. • Examines the propagation of the AWAKE ionization laser through rubidium vapor at design density on a small scale and reduced intensity with a linear numerical model compared to experimental results. • Discusses physics of pulse propagation through the vapor at high intensity regime where strong ionization occurs within the laser pulse.

Crystal structure of rubidium methyldiazotate

Directory of Open Access Journals (Sweden)

Tobias Grassl

2017-02-01

Full Text Available The title compound, Rb+·H3CN2O−, has been crystallized in liquid ammonia as a reaction product of the reductive ammonolysis of the natural compound streptozocin. Elemental rubidium was used as reduction agent as it is soluble in liquid ammonia, forming a blue solution. Reductive bond cleavage in biogenic materials under kinetically controlled conditions offers a new approach to gain access to sustainably produced raw materials. The anion is nearly planar [dihedral angle O—N—N—C = −0.4 (2°]. The Rb+ cation has a coordination number of seven, and coordinates to five anions. One anion is bound via both its N atoms, one by both O and N, two anions are bound by only their O atoms, and the last is bound via the N atom adjacent to the methyl group. The diazotate anions are bridged by cations and do not exhibit any direct contacts with each other. The cations form corrugated layers that propagate in the (-101 plane.

Low-temperature phase transformation in rubidium and cesium superoxides

International Nuclear Information System (INIS)

Alikhanov, R.A.; Toshich, B.S.; Smirnov, L.S.

1980-01-01

Crystal structures of rubidium and cesium superoxides which are two interpenetrating lattices of metal ions and oxygen molecule ions reveal a number of phase transformations with temperature decrease. Crystal-phase transformations in CsO 2 are 1-2, 2-3 and low temperature one 3-4 at 378, 190 and 10 K. Low temperature transition is considered as the instability of lattice quadrupoles of oxygen molecule ions to phase transformation of the order-disorder type. Calculated temperatures of low temperature phase transformations in PbO 2 and CsO 2 agree with experimental calculations satisfactory [ru

Photoabsorption spectra of potassium and rubidium near the K-edge

International Nuclear Information System (INIS)

Azuma, Y.; Berry, H.G.; Cowan, P.L.

1995-01-01

We have used a high-temperature circulating heat-pipe absorption cell together with monochromatized X-ray beams at the X24A and X23A2 beam lines at the NSLS to obtain photoabsorption spectra of potassium and rubidium at their K- and KM-edges. The photon-energy ranges lay near 3600 eV and 15200 eV, respectively. We have also obtained first measurements of the LII and LIII edges in cesium. Although the K-edge photoabsorptions of the rare gases have been studied, there is little previous work on other atomic vapors. Most of the edges and resonance peaks that we observed have now been identified using Dirac Hartree-Fock calculations. As a check, we have compared these results with those obtained previously in closed-shell rare-gas absorption spectra. The absolute energies were obtained through a calibration of the X24A systems using measurements of several metal L-edges in the 3200-5000 eV energy range. We found that the 4p resonance in potassium is significantly enhanced compared with the corresponding situation in argon. Likewise, the 5p resonance in krypton is unresolved from the background ionization cross section, whereas it is well resolved in rubidium. As suggested by Amusia, these enhancements may be due to the enhanced potential seen in the excited state of the alkali systems as a result of the presence of an s-electron which reduces the nuclear shielding

One step beyond the electric dipole approximation: An experiment to observe the 5p → 6p forbidden transition in atomic rubidium

Science.gov (United States)

Ponciano-Ojeda, F.; Hernández-Gómez, S.; Mojica-Casique, C.; Ruiz-Martínez, E.; López-Hernández, O.; Colín-Rodríguez, R.; Ramírez-Martínez, F.; Flores-Mijangos, J.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J.

2018-01-01

An advanced undergraduate experiment to study the 5 P 3 / 2 → 6 P 3 / 2 electric quadrupole transition in rubidium atoms is presented. The experiment uses two external cavity diode lasers, one operating at the D2 rubidium resonance line and the other built with commercial parts to emit at 911 nm. The lasers produce the 5 s → 5 p → 6 p excitation sequence in which the second step is the forbidden transition. Production of atoms in the 6 P 3 / 2 state is observed by detection of the 420 nm fluorescence that results from electric dipole decay into the ground state. Lines whose widths are significantly narrower than the Doppler width are used to study the hyperfine structure of the 6 P 3 / 2 state in rubidium. The spectra illustrate characteristics unique to electric dipole forbidden transitions, like the electric quadrupole selection rules; they are also used to show general aspects of two-color laser spectroscopy such as velocity selection and hyperfine pumping.

Dielectric dispersion in pure and doped lithium rubidium sulphate

Science.gov (United States)

Kassem, M. E.; El-Muraikhi, M.; Al-Houty, L.; Mohamed, A. A.

The frequency (102 - 105 Hz) dependence of the dielectric properties of lithium rubidium sulphate (LRS) are reported in the vicinity of the transition temperature Tc = 477 K. The a.c. conductivity σ(ω) shows a strong temperature dependence and weak frequency response. The dielectric constant in this region shows a strong frequency dispersion. A Cole-Cole diagram was used to determine the distribution parameter and the molecular relaxation time. The effect of doping with Dy+3, Sm+3 and V+3, was also studied. It was found that doping gives rise to localized states which produce a disorder in the structure of LiRbSO4.

Crystal structure of rubidium peroxide ammonia disolvate

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Tobias Grassl

2017-02-01

Full Text Available The title compound, Rb2O2·2NH3, has been obtained as a reaction product of rubidium metal dissolved in liquid ammonia and glucuronic acid. As a result of the low-temperature crystallization, a disolvate was formed. To our knowledge, only one other solvate of an alkali metal peroxide is known: Na2O2·8H2O has been reported by Grehl et al. [Acta Cryst. (1995, C51, 1038–1040]. We determined the peroxide bond length to be 1.530 (11 Å, which is in accordance with the length reported by Bremm & Jansen [Z. Anorg. Allg. Chem. (1992, 610, 64–66]. One of the ammonia solvate molecules is disordered relative to a mirror plane, with 0.5 occupancy for the corresponding nitrogen atom.

A laser system for the spectroscopy on highly charged ions, tellurium molecules, and Rydberg states of rubidium atoms; Ein Lasersystem zur Spektroskopie von hochgeladenen Ionen, Tellurmolekuelen und Rubidium-Rydberg-Zustaenden

Energy Technology Data Exchange (ETDEWEB)

Albrecht, Sebastian

2014-08-15

Optical measuring methods allow the detection and identification of the atomic structure with extraordinary precision. Deviations to theoretical predictions can indicate unknown physical effects. Therefore, precise measurements on the atomic structure continue to be of large relevance. In this work, a laser system for precision spectroscopy on Bismuth ({sup 209}Bi{sup 82+}), Tellurium ({sup 130}Te{sub 2}) and Rydberg states of Rubidium ({sup 85}Rb) has been built and characterized. Spectroscopic measurements on Tellurium and Rubidium have been achieved with this setup. The system consists of a two-stage frequency doubled diode laser, stabilized via a cavity and an RF-offsetlock to arbitrary wavelengths with absolute high stability. The setup of the laser system will be presented and the systematic error caused by the refractive index of air inside the transfer cavity will be discussed. A stability of better then 6.14 MHz at 244 nm is obtained for planned experiments on the ground state hyperfine splitting of {sup 209}Bi{sup 82+}. This will allow an increase in precision of more then four orders of magnitude for this measurement. Further increase in precision can be achieved by using an evacuated cavity. The obtained stability is measured by comparison of the laser frequency to absorption lines of Tellurium ({sup 130}Te{sub 2}). Eight reference lines, known from literature, spanning the region from 613720.717 GHz to 616803.545 GHz have been measured. The frequency measurements of three lines, coinciding with the emission spectrum of an argon-ion-laser, show deviations with respect to the published frequencies. Further inconsistencies in literature are cleared. Part of this work is also the precise measurement of 843 Doppler-free {sup 130}Te{sub 2} reference lines spanning the frequency range from 613881.150 GHz to 616614.258 GHz at a precision of better then 4 MHz for most lines. Additionally, measurements on electromagnetically induced transparency (EIT) using

Correlations between potassium, rubidium and cesium (133Cs and 137Cs) in sporocarps of Suillus variegatus in a Swedish boreal forest

International Nuclear Information System (INIS)

Vinichuk, M.; Rosen, K.; Johanson, K.J.; Dahlberg, A.

2011-01-01

An analysis of sporocarps of ectomycorrhizal fungi Suillus variegatus assessed whether cesium ( 133 Cs and 137 Cs) uptake was correlated with potassium (K) or rubidium (Rb) uptake. The question was whether intraspecific correlations of Rb, K and 133 Cs mass concentrations with 137 Cs activity concentrations in sporocarps were higher within, rather than among, different fungal species, and if genotypic origin of sporocarps within a population affected uptake and correlation. Sporocarps (n = 51) from a Swedish forest population affected by the fallout after the Chernobyl accident were studied. The concentrations were 31.9 ± 6.79 g kg -1 for K (mean ± SD, dwt), 0.40 ± 0.09 g kg -1 for Rb, 8.7 ± 4.36 mg kg -1 for 133 Cs and 63.7 ± 24.2 kBq kg -1 for 137 Cs. The mass concentrations of 133 Cs correlated with 137 Cs activity concentrations (r = 0.61). There was correlation between both 133 Cs concentrations (r = 0.75) and 137 Cs activity concentrations (r = 0.44) and Rb, but the 137 Cs/ 133 Cs isotopic ratio negatively correlated with Rb concentration. Concentrations of K and Rb were weakly correlated (r = 0.51). The 133 Cs mass concentrations, 137 Cs activity concentrations and 137 Cs/ 133 Cs isotopic ratios did not correlate with K concentrations. No differences between, within or, among genotypes in S. variegatus were found. This suggested the relationships between K, Rb, 133 Cs and 137 Cs in sporocarps of S. variegatus is similar to other fungal species. - Highlights: → We studied uptake of Cs ( 133 Cs and 137 Cs), K and Rb by Suillus variegates sporocarps. → Genotypic origin of fungus did not affect uptake of studied elements (isotopes). → Genotypic origin did not affect correlation between Cs ( 133 Cs and 137 Cs), K and Rb.

Emission characteristics of plasma based on xenon-rubidium bromide mixture

Science.gov (United States)

Heneral, A. A.; Avtaeva, S. V.

2017-10-01

Luminescence spectra of a longitudinal pulse-periodic discharge in xenon mixture with rubidium bromide vapors (Xe-RbBr) are studied experimentally at low pressures. The conditions leading to the appearance of intense bands of ultraviolet radiation of exciplex XeBr* molecules in the spectral interval between 200 and 400 nm are found. The highest yield of UV radiation of XeBr* molecules is achieved when the temperature of discharge-tube walls is equal to 750°C. A maximum power of UV radiation from the entire plasma volume as high as 4.8 W is obtained.

Electromagnetically induced two-photon transparency in rubidium atoms

International Nuclear Information System (INIS)

Wang, D.; Gao, J.Y.; Xu, J.H.; Bassani, F.; La Rocca, G.C.; Salerno Univ.

2001-01-01

We present an experimental demonstration of electromagnetically induced two-photon transparency (EITT) in room temperature rubidium vapor. The 8S 1/2 to 5P 1/2 fluorescence is used to monitor the 5S 1/2 (F = 3) to 8S 1/2 (F = 3) two-photon absorption near resonance with the intermediate state 5P 3/2 . A controlling pump laser beam is employed to coherently couple the 5P 3/2 and 5D 5/2 states, thus producing two dressed intermediate states which give rise to destructive interference in the two-photon transition. An induced two-photon transparency of about 80% has been obtained at resonance; our experimental findings are in good agreement with the general theory of Agarwal et al. (1996), when the appropriate spectroscopic parameters are used. (orig.)

Przebieg mitozy w korzeniach siewek pszenicy pod wpływem rubidu [Course of mitosis in root seedlings of Triticum aestivum L. under the influence of rubidium

Directory of Open Access Journals (Sweden)

Kazimierz Olech

2015-06-01

Full Text Available The depresion of mitosis as a result of rubidium action illustrated by the lower frequency of mitosis was found in an investigation made on roots of wheat seedlings grown on a nutrient medium which the total amount of potassium or a half of it was replaced by rubidium. The lower mitotic activity was caused by limited number of nuclei beginning prophase and by a prolonged duration of metaphase.

DISTRIBUTION OF 86RUBIDIUM AND METIONINE 75SELENIUM IN ORGANS OF RATS AFTER EXERCISE AND TREATMENT WITH PROTEIN HYDROLYZATE AND VITAMIN C

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Miroslav Marinov

2013-02-01

Full Text Available Purpose of the study is to track in, the blood flow and the metabolism in 15 organs of experimental rats, which are subjected to severe physical strain, treated with protein hydrolyzate and vitamine C (Vit. C. The animals are divided into one control and 4 experimental groups. After 30 minutes of swimming they are treated with already used produces, methionine 75selenium and and after another 2 hours of swimming, with 86rubidium. After being euthanized with thiopental and an autopsied, the following organs are taken from the rats: pancreas, spleen, testicles, duodenum, a part of small intestine and colon, adrenals, kidneys, liver, lungs, heart, aorta, a piece of muscle, part of a brain and stomach. Percentage of the activity per gram of tissue is determined, of the total activity, of the two isotopes for every organ and them being compared. Physical strain deteriorates blood flow and reduces the accumulation of methionine 75selenium, while the treatment with the hydrolyzate and Vit. C has a beneficial effect in almost all organs.

Lithium and rubidium extraction from zinnwaldite by alkali digestion process: Sintering mechanism and leaching kinetics

Czech Academy of Sciences Publication Activity Database

Vu, H.; Bernardi, J.; Jandová, J.; Vaculíková, Lenka; Goliáš, V.

2013-01-01

Roč. 123, č. 1 (2013), s. 9-17 ISSN 0301-7516 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : zinnwaldite * lithium * rubidium * sintering mechanism * leaching kinetics Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.461, year: 2013 http://www.sciencedirect.com/science/article/pii/S0301751613001087

Crystal structure of rubidium methyl-diazo-tate.

Science.gov (United States)

Grassl, Tobias; Korber, Nikolaus

2017-02-01

The title compound, Rb + ·H 3 CN 2 O - , has been crystallized in liquid ammonia as a reaction product of the reductive ammonolysis of the natural compound streptozocin. Elemental rubidium was used as reduction agent as it is soluble in liquid ammonia, forming a blue solution. Reductive bond cleavage in biogenic materials under kinetically controlled conditions offers a new approach to gain access to sustainably produced raw materials. The anion is nearly planar [dihedral angle O-N-N-C = -0.4 (2)°]. The Rb + cation has a coordination number of seven, and coordinates to five anions. One anion is bound via both its N atoms, one by both O and N, two anions are bound by only their O atoms, and the last is bound via the N atom adjacent to the methyl group. The diazo-tate anions are bridged by cations and do not exhibit any direct contacts with each other. The cations form corrugated layers that propagate in the (-101) plane.

Coherence effects in three- and four-level laser-cooled rubidium systems

International Nuclear Information System (INIS)

De Echaniz, Sebastian R.

2002-01-01

This thesis presents developmental work on the existing magneto-optical trap (MOT) system and novel studies of coherence effects. The developmental work was carried out on the experimental apparatus used previously in this laboratory in order to perform experiments to study coherence effects in three- and four-level rubidium systems in the MOT. This developmental work includes the upgrading and installation of new laser systems, the improvement of the MOT, the installation of data acquisition hardware and software, and the commissioning of a new 'second generation' MOT. As part of our studies of coherence effects, we present a wide-ranging theoretical and experimental study of non-adiabatic transient phenomena in a Λ system which exhibits electromagnetically induced transparency when a strong coupling field is rapidly switched on or off using a Pockels cell. The theoretical treatment uses a Laplace transform approach as well as standard numerical methods to solve the time-dependent density matrix equation. The results show clear Rabi oscillations and transient gain without population inversion of a weak probe in parameter regions not previously studied, and provide insight into the transition dynamics between bare a dressed states. Experimental studies of a doubly driven V system are also reported, together with a theoretical dressed-state analysis of such systems. The expected three-peak spectrum is explored for various coupling field strengths and detunings. In all this work we have found good agreement between the theory and the experimental spectra once light shifts and uncoupled absorption in the rubidium system are taken into account. (author)

Hydrologic inferences from strontium isotopes in pore water from the unsaturated zone at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Marshall, B.D.; Futa, K.; Peterman, Z.E.

1997-01-01

Calcite is ubiquitous at Yucca Mountain, occurring in the soils and as fracture and cavity coatings within the volcanic tuff section. Strontium is a trace element in calcite, generally at the tens to hundreds of ppm level. Because calcite contains very little rubidium and the half-life of the 87 Rb parent is billions of years, the 87 Sr/ 86 Sr ratios of the calcite record the ratio in the water from which the calcite precipitated. Dissolution and reprecipitation does not alter these compositions so that, in the absence of other sources of strontium, one would expect the strontium ratios along a flow path to preserve variations inherited from strontium in the soil zone. Strontium isotope compositions of calcites from various settings in the Yucca Mountain region have contributed to the understanding of the unsaturated zone (UZ), especially in distinguishing unsaturated zone calcite from saturated zone calcite. Different populations of calcite have been compared, either to group them together or distinguish them from each other in terms of their strontium isotope compositions. Ground water and perched water have also been analyzed; this paper presents strontium isotope data obtained on pore water

Dual-channel amplification in a single-mode diode laser for multi-isotope laser cooling

International Nuclear Information System (INIS)

Booth, James L.; Van Dongen, Janelle; Lebel, Paul; Klappauf, Bruce G.; Madison, Kirk W.

2007-01-01

The output from two grating-stabilized external-cavity diode lasers were injected into a single-mode diode laser. Operating at a wavelength of 780 nm, this laser produced ∼50 mW of power with two main frequency components of the same spectral characteristics of the seed lasers. The power ratio of the amplified components was freely adjustable due to gain saturation, and amplification was observed for frequency differences of the two seed lasers in the range from 73 MHz to 6.6 GHz. This system was used to realize a dual isotope magneto-optic trap (MOT) for rubidium ( 85 Rb and 87 Rb). The resulting position and cloud size of the dual isotope MOT was the same as that of the single species MOTs to within ±10 and ±20 μm, respectively. We also characterized the additional spectral components produced by four wave mixing (FWM) in the diode laser amplifier and utilized a particular FWM sideband to realize hyperfine pumping and subsequent laser trapping of 85 Rb in the absence of a 'repump' laser dedicated to hyperfine pumping

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

Energy Technology Data Exchange (ETDEWEB)

Kotasidis, Fotis A. [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom); Angelis, Georgios I. [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia); Anton-Rodriguez, Jose; Matthews, Julian C. [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom); Reader, Andrew J. [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King' s College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland); Geneva Neuroscience Centre, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30 001, Groningen 9700 RB (Netherlands)

2014-05-15

recovery image reconstruction. The benefits are expected to be more substantial for more energetic positron emitting isotopes such as Oxygen-15 and Rubidium-82.

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

International Nuclear Information System (INIS)

Kotasidis, Fotis A.; Angelis, Georgios I.; Anton-Rodriguez, Jose; Matthews, Julian C.; Reader, Andrew J.; Zaidi, Habib

2014-01-01

recovery image reconstruction. The benefits are expected to be more substantial for more energetic positron emitting isotopes such as Oxygen-15 and Rubidium-82

Isotope specific resolution recovery image reconstruction in high resolution PET imaging.

Science.gov (United States)

Kotasidis, Fotis A; Angelis, Georgios I; Anton-Rodriguez, Jose; Matthews, Julian C; Reader, Andrew J; Zaidi, Habib

2014-05-01

benefits are expected to be more substantial for more energetic positron emitting isotopes such as Oxygen-15 and Rubidium-82.

A thermodynamic assessment of the behavior of cesium and rubidium in reactor fuel elements

International Nuclear Information System (INIS)

Kohli, R.

1981-01-01

A comprehensive thermodynamic model is developed to assess the reaction and transport behavior of fission products in LWR fuel elements. The emphasis is on the chemistry of cesium and rubidium and their reactions with the fuel, other fission products, and the zircaloy cladding. Equilibrium thermodynamic calculations have been performed on the most plausible reactions to predict the chemical state of the fission products. The relevance of the predictions to pellet-clad interaction failures is discussed in detail. (orig.)

Adsorption of Cesium, Strontium, and Rubidium radionuclides in the Mag-molecular process: The influence of important factors

Directory of Open Access Journals (Sweden)

Fatemeh Tangestani

2017-09-01

Full Text Available In this study, the adsorption of cesium, strontium, and rubidium radionuclides by ferritin magmolecules in a batch system was investigated under different experimental conditions. The experiments were conducted in a pilot plant that involved the contactor unit and the magnetic separator unit. The impact of the pollutant concentrations, adsorbent concentration, and pH on the efficiency of the process were investigated thoroughly. The maximum recovery of radionuclides in the studied domain were 57.05%, 85.42% and 71.82% for Cs+, Sr2+ and Rb+ ,respectively, in which the pollutant concentration was 363.63 mg/l, the adsorbent concentration was 0.011 g/l, and the pH was 7.5. The results showed that the ferritin adsorbent in the magmolecular process manifested a higher efficiency in adsorbing the bivalent ions of strontium compared to the univalent ions of cesium and rubidium. Furthermore, the results were statistically analyzed and the model and residual plots of each radionuclide were presented. The results also signified  relationships between the independent variables and recovery.

Noninvasive quantification of regional myocardial perfusion with rubidium-82 and positron emission tomography. Exploration of a mathematical model

International Nuclear Information System (INIS)

Herrero, P.; Markham, J.; Shelton, M.E.; Weinheimer, C.J.; Bergmann, S.R.

1990-01-01

Positron emission tomography (PET) centers without cyclotrons use generator-produced rubidium-82 (82Rb) for assessment of myocardial perfusion. The aim of the present study was to determine whether myocardial blood flow could be assessed quantitatively with 82Rb and PET. Because the myocardial extraction fraction of 82Rb varies inversely and nonlinearly with flow and cannot be measured conveniently with PET, we used an experimentally derived mathematical function defining the relation between single-pass extraction fraction of 82Rb and flow to obviate the necessity of measuring the extraction fraction directly. Myocardial blood flow in absolute terms (ml/g/min) was estimated from dynamic PET scans after intravenous administration of 82Rb in intact dogs and compared with flows measured with radiolabeled microspheres. In 36 comparisons in 13 dogs studied at rest, or after coronary occlusion, reperfusion, or after coronary hyperemia induced with intravenous dipyridamole, over the flow range from 0.2 to 2.0 ml/g/min, estimates of perfusion with rubidium correlated well with flows measured concomitantly with microspheres, although there was a slight underestimation of flow with rubidium (flow by 82Rb = 0.92 x flow by microspheres-0.021, r = 0.83). In general, estimates of flow in ischemic regions were less reliable than estimates for regions with normal flow. Thus, although the relation between myocardial extraction and retention of 82Rb and flow can vary under a variety of physiological and pathophysiological conditions, this study demonstrates the ability to obtain quantitative estimates of myocardial blood flow with 82Rb and PET under carefully defined conditions without measuring the extraction fraction directly

Chemical and isotopic studies of granitic Archean rocks, Owl Creek Mountains, Wyoming: Geochronology of an Archean granite, Owl Creek Mountains, Wyoming

International Nuclear Information System (INIS)

Hedge, C.E.; Simmons, K.R.; Stuckless, J.S.

1986-01-01

Rubidium-strontium analyses of whole-rock samples of an Archean granite from the Owl Creek Mountains, Wyo., indicate an intrusive age of 2640 ± 125 Ma. Muscovite-bearing samples give results suggesting that these samples were altered about 2300 Ma. This event may have caused extensive strontium loss from the rocks as potassium feldspar was altered to muscovite. Alteration was highly localized in nature as evidence by unaffected rubidium-strontium mineral ages in the Owl Creek Mountains area. Furthermore, the event probably involved a small volume of fluid relative to the volume of rock because whole-rock δ 18 O values of altered rocks are not distinct from those of unaltered rocks. In contrast to the rubidium-strontium whole-rock system, zircons from the granite have been so severely affected by the alteration event, and possibly by a late-Precambrian uplift event, that the zircon system yields little usable age information. The average initial 87 Sr/ 86 Sr (0.7033 ± 0.0042) calculated from the isochron intercept varies significantly. Calculated initial 87 Sr/ 86 Sr ratios for nine apparently unaltered samples yield a range of 0.7025 to 0.7047. These calculated initial ratios correlate positively with whole-rock δ 18 O values; and, therefore, the granite was probably derived from an isotopically heterogeneous source. The highest initial 87 Sr/ 86 Sr ratio is lower than the lowest reported for the metamorphic rocks intruded by the granite as it would have existed at 2640 Ma. Thus, the metamorphic sequence, at its current level of exposure, can represent no more than a part of the protolith for the granite

Rubidium 2,4,6-trioxo-1,3-diazinan-5-ide–1,3-diazinane-2,4,6-trione–water (1/1/1

Directory of Open Access Journals (Sweden)

Marlena Gryl

2011-05-01

Full Text Available The asymmetric unit of the title compound, Rb+·C4H3N2O3−·C4H4N2O3·H2O, consists of one rubidium cation, a barbituric acid molecule, a barbiturate anion and one water molecule. The rubidium ion has seven close-contact interactions with O atoms, with Rb...O distances ranging from 2.8594 (16 to 3.2641 (14 Å. These seven O atoms together with an eighth O atom at 3.492 (2 Å away from Rb form a distorted polyhedron with shape intermediate between an antiprism and a dodecahedron. The Rb+ ions connect layers built of organic components and water molecules linked via N—H...O and O—H...O hydrogen bonds.

Story of rubidium-82 and advantages for myocardial perfusion PET imaging

Directory of Open Access Journals (Sweden)

Jean-Francois eChatal

2015-09-01

Full Text Available Rubidium-82 has a long story, starting in 1954. After preclinical studies in dogs showing that myocardial uptake of this radionuclide was directly proportional to myocardial blood flow, clinical studies were performed in the 80s leading to an approval in the USA in 1989. From that time thousands of patients have been tested and their results have been reported in 3 meta-analyses. Pooled patient-based sensitivity and specificity were respectively 0.91 and 0.90. By comparison with 99mTc-SPECT, 82Rb-PET had a much better diagnostic accuracy, especially in obese patients with BMI (Body Mass Index ≥30 kg/m2 (85% versus 67% with SPECT and in women with large breasts. A great advantage of 82Rb-PET is its capacity to accurately quantify myocardial blood flow. Quite importantly it has been recently shown that coronary flow reserve is associated with adverse cardiovascular events independently of luminal angiographic severity. Moreover coronary flow reserve is a functional parameter particularly useful in the estimate of microvascular dysfunction such as in diabetes mellitus. Due to the very short half-life of rubidium-82, the effective dose calculated for a rest/stress test is roughly equivalent to the annual natural exposure and even less when stress-only is performed with a low activity compatible with a good image quality with the last generation 3D PET scanners.There is still some debate on the relative advantages of 82Rb-PET with regard to 99mTc-SPECT. For the last ten years, great technological advances substantially improved performances of SPECT with its accuracy getting closer to this of 82Rb/PET. Currently the main advantages of PET are its capacity to accurately quantify myocardial blood flow and to deliver a low radiation exposure.

Grain size effect on Sr and Nd isotopic compositions in eolian dust. Implications for tracing dust provenance and Nd model age

International Nuclear Information System (INIS)

Feng Jinliang; Zhu Liping; Zhen Xiaolin; Hu Zhaoguo

2009-01-01

Strontium (Sr) and neodymium (Nd) isotopic compositions enable identification of dust sources and reconstruction of atmospheric dispersal pathways. The Sr and Nd isotopic compositions in eolian dust change systematically with grain size in ways not yet fully understood. This study demonstrates the grain size effect on the Sr and Nd isotopic compositions in loess and 2006 dust fall, based on analyses of seven separated grain size fractions. The analytical results indicate that Sr isotopic ratios strongly depend on the grain size fractions in samples from all types of eolian dust. In contrast, the Nd isotopic ratios exhibit little variation in loess, although they vary significantly with grain size in samples from a 2006 dust fall. Furthermore, Nd model ages tend to increase with increasing grain size in samples from all types of eolian dust. Comparatively, Sr isotopic compositions exhibit high sensitively to wind sorting, while Nd isotopic compositions show greater sensitively to dust origin. The principal cause for the different patterns of Sr and Nd isotopic composition variability with grain size appears related to the different geochemical behaviors between rubidium (Rb) and Sr, and the similar geochemical behaviors between samarium (Sm) and Nd. The Nd isotope data indicate that the various grain size fractions in loess have similar origins for each sample. In contrast, various provenance components may separate into different grain size fractions for the studied 2006 dust fall. The Sr and Nd isotope compositions further confirm that the 2006 dust fall and Pleistocene loess in Beijing have different sources. The loess deposits found in Beijing and those found on the Chinese Loess Plateau also derive from different sources. Variations between Sr and Nd isotopic compositions and Nd model ages with grain size need to be considered when directly comparing analyses of eolian dust of different grain size. (author)

Pump-probe study of the formation of rubidium molecules by ultrafast photoassociation of ultracold atoms

Science.gov (United States)

McCabe, David J.; England, Duncan G.; Martay, Hugo E. L.; Friedman, Melissa E.; Petrovic, Jovana; Dimova, Emiliya; Chatel, Béatrice; Walmsley, Ian A.

2009-09-01

An experimental pump-probe study of the photoassociative creation of translationally ultracold rubidium molecules is presented together with numerical simulations of the process. The formation of loosely bound excited-state dimers is observed as a first step toward a fully coherent pump-dump approach to the stabilization of Rb2 into its lowest ground vibrational states. The population that contributes to the pump-probe process is characterized and found to be distinct from a background population of preassociated molecules.

Correlations between potassium, rubidium and cesium ({sup 133}Cs and {sup 137}Cs) in sporocarps of Suillus variegatus in a Swedish boreal forest

Energy Technology Data Exchange (ETDEWEB)

Vinichuk, M., E-mail: Mykhailo.Vinichuk@slu.s [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, SE-750 07 Uppsala (Sweden); Department of Ecology, Zhytomyr State Technological University, 103 Cherniakhovsky Str., 10005 Zhytomyr (Ukraine); Rosen, K.; Johanson, K.J. [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, SE-750 07 Uppsala (Sweden); Dahlberg, A. [Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, 750 07 Uppsala (Sweden)

2011-04-15

An analysis of sporocarps of ectomycorrhizal fungi Suillus variegatus assessed whether cesium ({sup 133}Cs and {sup 137}Cs) uptake was correlated with potassium (K) or rubidium (Rb) uptake. The question was whether intraspecific correlations of Rb, K and {sup 133}Cs mass concentrations with {sup 137}Cs activity concentrations in sporocarps were higher within, rather than among, different fungal species, and if genotypic origin of sporocarps within a population affected uptake and correlation. Sporocarps (n = 51) from a Swedish forest population affected by the fallout after the Chernobyl accident were studied. The concentrations were 31.9 {+-} 6.79 g kg{sup -1} for K (mean {+-} SD, dwt), 0.40 {+-} 0.09 g kg{sup -1} for Rb, 8.7 {+-} 4.36 mg kg{sup -1} for {sup 133}Cs and 63.7 {+-} 24.2 kBq kg{sup -1} for {sup 137}Cs. The mass concentrations of {sup 133}Cs correlated with {sup 137}Cs activity concentrations (r = 0.61). There was correlation between both {sup 133}Cs concentrations (r = 0.75) and {sup 137}Cs activity concentrations (r = 0.44) and Rb, but the {sup 137}Cs/{sup 133}Cs isotopic ratio negatively correlated with Rb concentration. Concentrations of K and Rb were weakly correlated (r = 0.51). The {sup 133}Cs mass concentrations, {sup 137}Cs activity concentrations and {sup 137}Cs/{sup 133}Cs isotopic ratios did not correlate with K concentrations. No differences between, within or, among genotypes in S. variegatus were found. This suggested the relationships between K, Rb, {sup 133}Cs and {sup 137}Cs in sporocarps of S. variegatus is similar to other fungal species. - Highlights: {yields} We studied uptake of Cs ({sup 133}Cs and {sup 137}Cs), K and Rb by Suillus variegates sporocarps. {yields} Genotypic origin of fungus did not affect uptake of studied elements (isotopes). {yields} Genotypic origin did not affect correlation between Cs ({sup 133}Cs and {sup 137}Cs), K and Rb.

Velocity-selective dark states in rubidium

International Nuclear Information System (INIS)

Esslinger, T.

1995-06-01

There are two recent developments exerting a strong influence on atomic physics: cooling of atomic gases with laser light, and optics with matter waves. The report addresses both fields. A mechanism for the cooling of atoms is examined, with the wave character of the atom playing an important part in the process. A novel atomic beam experiment has been worked out and is reported which represents application of this cooling method to an alkali atom for the first time. The basic principle of the cooling process is that atoms are optically pumped into quantum states by means of interaction with a standing laser wave, the quantum states having a sharply defined momentum, decoupled from the light field. These states are called dark states, as their dipole moment does not couple to the field of a resonant laser wave. In a one-dimensional standing laser wave with spatially varying polarization, the dark state is delocalised. This state is called velocity-selective dark state (VSDS). So far, such VSDS have only been observed in helium atoms. We succeded for the first time in detecting the population of VSDS with an experiment using alkali atoms. Atoms of a cold rubidium beam are optically pumped into VSDS by way of interaction with a one-dimensional standing laser wave. (orig./MM) [de

Millimeter wave detection via Autler-Townes splitting in rubidium Rydberg atoms

Energy Technology Data Exchange (ETDEWEB)

Gordon, Joshua A., E-mail: josh.gordon@nist.gov; Holloway, Christopher L. [National Institute of Standards and Technology (NIST), Electromagnetics Division, U.S. Department of Commerce, Boulder Laboratories, Boulder, Colorado 80305 (United States); Schwarzkopf, Andrew; Anderson, Dave A.; Miller, Stephanie; Thaicharoen, Nithiwadee; Raithel, Georg [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2014-07-14

In this paper, we demonstrate the detection of millimeter waves via Autler-Townes splitting in {sup 85}Rb Rydberg atoms. This method may provide an independent, atom-based, SI-traceable method for measuring mm-wave electric fields, which addresses a gap in current calibration techniques in the mm-wave regime. The electric-field amplitude within a rubidium vapor cell in the WR-10 wave guide band is measured for frequencies of 93.71 GHz and 104.77 GHz. Relevant aspects of Autler-Townes splitting originating from a four-level electromagnetically induced transparency scheme are discussed. We measured the E-field generated by an open-ended waveguide using this technique. Experimental results are compared to a full-wave finite element simulation.

Dynamics of solvation and desolvation of rubidium attached to He nanodroplets

International Nuclear Information System (INIS)

Vangerow, J. von; John, O.; Stienkemeier, F.; Mudrich, M.

2015-01-01

The real-time dynamics of photoexcited and photoionized rubidium (Rb) atoms attached to helium (He) nanodroplets is studied by femtosecond pump-probe mass spectrometry. While excited Rb atoms in the perturbed 6p-state (Rb * ) desorb off the He droplets, Rb + photoions tend to sink into the droplet interior when created near the droplet surface. The transition from Rb + solvation to full Rb * desorption is found to occur at a delay time τ ∼ 600 fs for Rb * in the 6pΣ-state and τ ∼ 1200 fs for the 6pΠ-state. Rb + He ions are found to be created by directly exciting bound Rb * He exciplex states as well as by populating bound Rb + He-states in a photoassociative ionization process

Dynamics of solvation and desolvation of rubidium attached to He nanodroplets

Science.gov (United States)

von Vangerow, J.; John, O.; Stienkemeier, F.; Mudrich, M.

2015-07-01

The real-time dynamics of photoexcited and photoionized rubidium (Rb) atoms attached to helium (He) nanodroplets is studied by femtosecond pump-probe mass spectrometry. While excited Rb atoms in the perturbed 6p-state (Rb*) desorb off the He droplets, Rb+ photoions tend to sink into the droplet interior when created near the droplet surface. The transition from Rb+ solvation to full Rb* desorption is found to occur at a delay time τ ˜ 600 fs for Rb* in the 6pΣ-state and τ ˜ 1200 fs for the 6pΠ-state. Rb+He ions are found to be created by directly exciting bound Rb*He exciplex states as well as by populating bound Rb+He-states in a photoassociative ionization process.

Radiation Pressure in a Rubidium Optical Lattice: An Atomic Analog to the Photorefractive Effect

International Nuclear Information System (INIS)

Guibal, S.; Mennerat-Robilliard, C.; Larousserie, D.; Triche, C.; Courtois, J.; Grynberg, G.

1997-01-01

Probe gain in a rubidium optical lattice is observed when the probe and lattice beams have identical frequencies. This effect is shown to arise from the radiation pressure that shifts the atomic density distribution with respect to the optical potential. This effect is compared with two-beam coupling in photorefractive materials. The experimental results obtained by changing the parameters of the optical lattice (intensity, detuning, periodicity) are in reasonable agreement with numerical simulations based on the model case of a 1/2→3/2 atomic transition. copyright 1997 The American Physical Society

Demonstration of bicolor slow-light channelization in rubidium vapor

International Nuclear Information System (INIS)

Bashkansky, Mark; Fatemi, Fredrik K.; Reintjes, John; Dutton, Zachary; Steiner, Michael

2007-01-01

We experimentally demonstrate a proof-of-principle of a previously proposed 'channelization' architecture for wideband slow-light propagation in atomic vapors using electromagnetically induced transparency (EIT). We use two optical frequencies to generate a sine wave signal which is delayed in rubidium vapor. The optical frequencies were tuned near the EIT resonances of two Zeeman sublevels, which are shifted from each other well beyond the EIT linewidth by a uniform magnetic field. We varied the Zeeman shift between these two levels (relative to the optical frequency splitting) and measured the delay versus Zeeman shift. Significant delays were observed and were in agreement with a theoretical model treating each Zeeman sublevel as part of an independent three-level system. We achieved delay of a signal with a bandwidth 16 times the EIT linewidth and confirmed our earlier theoretical models that delay occurs only when the optical spectral separation slightly exceeds the Zeeman splitting

Mass measurements of neutron-rich strontium and rubidium isotopes in the region $A \\approx 100$ and development of an electrospray ionization ion source

CERN Document Server

de Roubin, Antoine

An extension of the atomic mass surface in the region $A \\approx 100$ is performed via mass measurements of the $^{100−102}$Sr and $^{100−102}$Rb isotopes with the ion-trap mass spectrometer ISOLTRAP at CERN-ISOLDE. The first direct mass measurements of $^{102}$Sr and $^{101,102}$Rb are reported here. These measurements confirm the continuation of the region of nuclear deformation with the increase of neutron number, at least as far as $N = 65$. In order to interpret the deformation in the strontium isotopic chain and to determine whether an onset of deformation is present in heavier krypton isotopes, a comparison is made between experimental values and theoretical calculations available in the literature. To complete this comparison, Hartree-Fock-Bogoliubov calculations for even and odd isotopes are also presented, illustrating the competition of nuclear shapes in the region. The development of an electrospray ionization ion source is presented. This source can deliver a large range of isobaric masses ...

The structure factor and the pair potential of liquid rubidium at temperatures between 450 K and 1,400 K

International Nuclear Information System (INIS)

Block de Priego, R.A.

1977-11-01

The structure factor S(Q) of liquid rubidium has been measured for temperatures between 450 K and 1400 K and pressures up to 200 atm. The corresponding densities varied between 1.42 and 0.98 g cm -3 . The incident energy of the neutrons was 3.4 MeV, the momentum transfer Q being 0.2 - 2.5 A -1 . A significant change in the order of the liquid has been registrated. Compressibility and electrical conductivity were derived from the structure factors and compared with the direct measured quantities, showing a good agreement. Further interpretation of the data was done by means of a hard core and a square well potential. Using these models it was already possible to get some information about the interactions between the rubidium atoms. A more exact calculation with a modified STLS model and a pseudopotential leads to a good description of the measured S(Q). In order to describe at high temperatures S(Q) for smaller values a new term had to be added to the pseudopotential. (orig.) [de

Radiative lifetime measurements of rubidium Rydberg states

International Nuclear Information System (INIS)

Branden, D B; Juhasz, T; Mahlokozera, T; Vesa, C; Wilson, R O; Zheng, M; Tate, D A; Kortyna, A

2010-01-01

We have measured the radiative lifetimes of ns, np and nd Rydberg states of rubidium in the range 28 ≤ n ≤ 45. To enable long-lived states to be measured, our experiment uses slow-moving (∼100 μK) 85 Rb atoms in a magneto-optical trap (MOT). Two experimental techniques have been adopted to reduce random and systematic errors. First, a narrow-bandwidth pulsed laser is used to excite the target nl Rydberg state, resulting in minimal shot-to-shot variation in the initial state population. Second, we monitor the target state population as a function of time delay from the laser pulse using a short-duration, millimetre-wave pulse that is resonant with a one- or two-photon transition to a higher energy 'monitor state', n'l'. We then selectively field ionize the monitor state, and detect the resulting electrons with a micro-channel plate. This signal is an accurate mirror of the nl target state population, and is uncontaminated by contributions from other states which are populated by black body radiation. Our results are generally consistent with other recent experimental results obtained using a method which is more prone to systematic error, and are also in excellent agreement with theory.

Dynamics of solvation and desolvation of rubidium attached to He nanodroplets

Energy Technology Data Exchange (ETDEWEB)

Vangerow, J. von; John, O.; Stienkemeier, F.; Mudrich, M., E-mail: mudrich@physik.uni-freiburg.de [Physikalisches Institut, Universität Freiburg, 79104 Freiburg (Germany)

2015-07-21

The real-time dynamics of photoexcited and photoionized rubidium (Rb) atoms attached to helium (He) nanodroplets is studied by femtosecond pump-probe mass spectrometry. While excited Rb atoms in the perturbed 6p-state (Rb{sup *}) desorb off the He droplets, Rb{sup +} photoions tend to sink into the droplet interior when created near the droplet surface. The transition from Rb{sup +} solvation to full Rb{sup *} desorption is found to occur at a delay time τ ∼ 600 fs for Rb{sup *} in the 6pΣ-state and τ ∼ 1200 fs for the 6pΠ-state. Rb{sup +}He ions are found to be created by directly exciting bound Rb{sup *}He exciplex states as well as by populating bound Rb{sup +}He-states in a photoassociative ionization process.

Chemical aspects of rubidium uranium sulphate for its use as a chemical standard for uranium

International Nuclear Information System (INIS)

Singh Mudher, K.D.; Khandekar, R.R.; Krishnan, K.; Jayadevan, N.C.; Sood, D.D.

1989-01-01

Rb 2 U(SO 4 ) 3 , a double sulphate of rubidium and uranium(IV) has been prepared and investigated for its use as a chemical standard for uranium. The compound can be easily prepared and crystallised in a pure form. The results of physico-chemical characterisation on preparation of 5-10 g. lots are described in this report. These studies suggest that the compound is anhydrous, stoichiometric, stable to atmospheric effects and easily soluble in acids and thus satisfies most of the criteria for a primary standard. (author). 13 refs., 4 figs., 6 tabs

Crystal structure of the low-temperature forms of cesium and rubidium orthophosphates

International Nuclear Information System (INIS)

Voronin, V.I.; Proskurina, N.V.; Goshchitskij, B.N.; Berger, I.F.; Sheptyakov, D.V.; Burmakin, E.I.; Stroev, S.S.; Shekhtman, G.Sh.

2008-01-01

Making use of the neutron diffraction data base Rietveld method one for the first time determined and made more clear the crystal structure of the low-temperature modifications of Cs 3 PO 4 cesium and Rb 3 PO 4 rubidium orthophosphates. Cs 3 PO 4 and Rb 3 PO 4 were found to be isostructural one as to K 3 PO 4 . The structure is a rhombic one (Pnma, Z=4 sp.gr.) with the following elementary cell parameters: a = 1.23177(6) nm, b=0.88948(4) nm, c=0.64197(3) nm and a = 1.17362(2) nm, b=0.81046(1) nm, c=0.615167(9) nm for Cs 3 PO 4 and Rb 3 PO 4 respectively [ru

Influence of modulation frequency in rubidium cell frequency standards

Science.gov (United States)

Audoin, C.; Viennet, J.; Cyr, N.; Vanier, J.

1983-01-01

The error signal which is used to control the frequency of the quartz crystal oscillator of a passive rubidium cell frequency standard is considered. The value of the slope of this signal, for an interrogation frequency close to the atomic transition frequency is calculated and measured for various phase (or frequency) modulation waveforms, and for several values of the modulation frequency. A theoretical analysis is made using a model which applies to a system in which the optical pumping rate, the relaxation rates and the RF field are homogeneous. Results are given for sine-wave phase modulation, square-wave frequency modulation and square-wave phase modulation. The influence of the modulation frequency on the slope of the error signal is specified. It is shown that the modulation frequency can be chosen as large as twice the non-saturated full-width at half-maximum without a drastic loss of the sensitivity to an offset of the interrogation frequency from center line, provided that the power saturation factor and the amplitude of modulation are properly adjusted.

Theoretical analyses of an injection-locked diode-pumped rubidium vapor laser.

Science.gov (United States)

Cai, He; Gao, Chunqing; Liu, Xiaoxu; Wang, Shunyan; Yu, Hang; Rong, Kepeng; An, Guofei; Han, Juhong; Zhang, Wei; Wang, Hongyuan; Wang, You

2018-04-02

Diode-pumped alkali lasers (DPALs) have drawn much attention since they were proposed in 2001. The narrow-linewidth DPAL can be potentially applied in the fields of coherent communication, laser radar, and atomic spectroscopy. In this study, we propose a novel protocol to narrow the width of one kind of DPAL, diode-pumped rubidium vapor laser (DPRVL), by use of an injection locking technique. A kinetic model is first set up for an injection-locked DPRVL with the end-pumped configuration. The laser tunable duration is also analyzed for a continuous wave (CW) injection-locked DPRVL system. Then, the influences of the pump power, power of a master laser, and reflectance of an output coupler on the output performance are theoretically analyzed. The study should be useful for design of a narrow-linewidth DPAL with the relatively high output.

Rubidium mobility in the apple-tree and autoradiography as an aid in measuring the distribution and spread of the root-system

International Nuclear Information System (INIS)

Katana, H.; Kuehn, W.

1974-01-01

Investigations were made on the usability of rubidium-86 for measuring the distribution and spread of the root system of fruit trees. The tracer techniques developed so far in horticulture are not applicable for various reasons. Therefore, a new method of autoradiography was developed. The results of the preliminary investigations are very promising

The composition of the saturated vapor and enthalpies of dimerization of rubidium and cesium pivalates

International Nuclear Information System (INIS)

Khoretonenko, N.M.; Rykov, A.N.; Korenev, Yu.M.

1998-01-01

The rubidium and cesium pivalates sublimation processes are studied through the Knudsen effusion method with the mass-spectral analysis of the gaseous phase composition. It is established that MPiv and M 2 Piv 2 and in small amounts M 3 Piv 3 and M 4 Piv 4 constitute the basic components in the saturated vapour of the rubidium and cesium pivalates. Sublimation enthalpies (kJ/mole) of monomers Δ S H T 0 =163.5±7.2 and dimers Δ S H T 0 (Cs 2 Piv 2 )-192.1±9.6 are determined. Dissociation enthalpies (kJ/mole) of the M 2 Piv 2 dimers by the second(2) and the third (3) laws of thermodynamics: Δ D H T 0 (Cs 2 Piv 2 )=137.1±5.4(2), Δ D H T 0 (Rb 2 Piv 2 )=138.2±10.2 (3); Δ D H T 0 (Cs 2 Piv 2 )-134.9±9.3 (2), Δ D H T 0 (Cs 2 Piv 2 )=136.8±10.8 (3) are calculated. Temperature dependence equations (210-300 deg C of partial pressures (Pa) of the MPiv, M 2 Piv 2 molecules: InP(RbPiv)=-(20099±674)/T+34.6±1.2; InP(Rb 2 Piv 2 )=-(23707±734)/T+40.4±1.4; InP(CsPiv)=-(19666±866)/T+34.1±1.6; InP(Cs 2 Piv 2 )=-(23106±1155)/T+39.5±2.1 are obtained

A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

Science.gov (United States)

McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

2007-09-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium

International Nuclear Information System (INIS)

McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L.

2007-01-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D 2 transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude

Generation of narrow-band polarization-entangled photon pairs at a rubidium D1 line

International Nuclear Information System (INIS)

Tian Long; Li Shujing; Yuan Haoxiang; Wang Hai

2016-01-01

Using the process of cavity-enhanced spontaneous parametric down-conversion (SPDC), we generate a narrow-band polarization-entangled photon pair resonant on the rubidium (Rb) D1 line (795 nm). The degenerate single-mode photon pair is selected by multiple temperature controlled etalons. The linewidth of generated polarization-entangled photon pairs is 15 MHz which matches the typical atomic memory bandwidth. The measured Bell parameter for the polarization-entangled photons S = 2.73 ± 0.04 which violates the Bell-CHSH inequality by ∼18 standard deviations. The presented entangled photon pair source could be utilized in quantum communication and quantum computing based on quantum memories in atomic ensemble. (author)

Study of the phase transition in lithium potassium rubidium sulfate system

Science.gov (United States)

Hamed, A. E.; Abd. El-Aziz, Y. M.; Madi, N. K.; Kassem, M. E.

1998-10-01

Specific heat, Cp, measurements have been performed in lithium potassium rubidium sulfate, (Li 0.5- x/2 K 0.5- x/2 Rb x) 2SO 4, system in a wide range of Rb 2SO 4 content ( x) ( x=0 up to x=10%). Measurements were made between 300 and 800 K with special attention paid to the phase transition at 708 K. It is shown that for small contents, ( x), ( x=0.2 up to x=2%) quantitative changes in the temperature dependence of specific heat Cp( T) around the transition point, T1, are observed. A larger content, x, results in essential changes in the critical behavior of Cp( T) and a considerable change in the phase transition accompanied by a progressive decrease in the thermodynamic parameters. The ratios of the Landau expansion coefficients change as the content of Rb 2SO 4 increases.

Engineering Photon-Photon Interactions within Rubidium-Filled Waveguides

Science.gov (United States)

Perrella, C.; Light, P. S.; Vahid, S. Afshar; Benabid, F.; Luiten, A. N.

2018-04-01

Strong photon-photon interactions are a required ingredient for deterministic two-photon optical quantum logic gates. Multiphoton transitions in dense atomic vapors have been shown to be a promising avenue for producing such interactions. The strength of a multiphoton interaction can be enhanced by conducting the interaction in highly confined geometries such as small-cross-section optical waveguides. We demonstrate, both experimentally and theoretically, that the strength of such interactions scale only with the optical mode diameter, d , not d2 as might be initially expected. This weakening of the interaction arises from atomic motion inside the waveguides. We create an interaction between two optical signals, at 780 and 776 nm, using the 5 S1 /2→5 D5 /2 two-photon transition in rubidium vapor within a range of hollow-core fibers with different core sizes. The interaction strength is characterized by observing the absorption and phase shift induced on the 780-nm beam, which is in close agreement with theoretical modeling that accounts for the atomic motion inside the fibers. These observations demonstrate that transit-time effects upon multiphoton transitions are of key importance when engineering photon-photon interactions within small-cross-section waveguides that might otherwise be thought to lead to enhanced optical nonlinearity through increased intensities.

Sound speed of isobaric heat capacity in the saturated and superheated vapour of cesium, rubidium and potassium

International Nuclear Information System (INIS)

Novikov, I.I.; Roschupkin, V.V.

1985-01-01

The paper reviews the work carried out on the thermodynamic properties of alkali metal vapours. The most systematic investigations concern the sound velocity measurements for saturated and superheated vapours of caesium, for saturated vapour of rubidium, and for superheated vapour of potassium. The Joule-Thompson coefficient has been studied in caesium vapour, and the isobaric heat capacity of potassium vapour has also been examined. The experimental methods for all these experiments are described, and the data obtained are presented in tabular form. (U.K.)

Dielectronic recombination rate coefficients of initially rubidium-like tungsten

International Nuclear Information System (INIS)

Wu, Z.; Zhang, Y.; Fu, Y.; Dong, C.; Surzhykov, A.; Fritzsche, S.

2015-01-01

Dielectric recombination (DR) is a dominant electron recombination process in plasmas. Tungsten ions are expected to be prominent impurities in fusion plasmas so the knowledge of DR rate coefficient of tungsten ions is important to model fusion plasmas. Ab initio calculations of DR rate coefficients of initially rubidium-like W 37+ ions have been performed for the electron temperatures from 1 eV to 5*10 4 eV, by using the Flexible Atomic Code based on the relativistic configuration-interaction method. Special attention has been paid to the partial contributions to total DR rate coefficients as associated with the excitation of individual subshells. A detailed comparison of the calculations shows that the excitation from 4p subshell dominates total DR rate coefficients followed by the excitations from 4s and 4d subshells, while the contribution of excitations from 3l (l = s, p, d) subshells becomes important only at high temperatures. Besides, it is found that the electron excitations associated with Δn = 0, 1 dominate at low-temperature plasmas, however, the excitations associated with Δn ≥ 2 become non-negligible at high-temperature ones

Structural, Mechanical and Thermodynamic Properties under Pressure Effect of Rubidium Telluride: First Principle Calculations

Directory of Open Access Journals (Sweden)

Bidai K.

2017-06-01

Full Text Available First-principles density functional theory calculations have been performed to investigate the structural, elastic and thermodynamic properties of rubidium telluride in cubic anti-fluorite (anti-CaF2-type structure. The calculated ground-state properties of Rb2Te compound such as equilibrium lattice parameter and bulk moduli are investigated by generalized gradient approximation (GGA-PBE that are based on the optimization of total energy. The elastic constants, Young’s and shear modulus, Poisson ratio, have also been calculated. Our results are in reasonable agreement with the available theoretical and experimental data. The pressure dependence of elastic constant and thermodynamic quantities under high pressure are also calculated and discussed.

Theoretical investigation of output features of a diode-pumped rubidium vapor laser

Science.gov (United States)

Wang, You; Cai, He; Zhang, Wei; Xue, Liangping; Wang, Hongyuan; Han, Juhong

2014-02-01

In the recent years, diode-pumped alkali lasers (DPALs) have been paid many attentions because of their excellent performances. In fact, the characteristics of a DPAL strongly depend on the physical features of buffer gases. In this report, we selected a diode-pumped rubidium vapor laser (DPRVL), which is an important type among three common DPALs, to investigate how the characteristics of a DPRVL are affected by different conditions. The results signify that the population ratio of two excitation energy-levels are close to that corresponding to thermal equilibrium as the pressure of buffer gases and the temperature of a vapor cell become higher. It has been found that quenching of the upper levels cannot be simply ignored especially for the case of weak pump. The conclusions are thought to be helpful for the configuration design of an end-pumped DPAL.

The impact of prompt gamma compensation on myocardial blood flow measurements with rubidium-82 dynamic PET.

Science.gov (United States)

Armstrong, Ian S; Memmott, Matthew J; Tonge, Christine M; Arumugam, Parthiban

2018-04-01

Rubidium-82 myocardial perfusion imaging is a well-established technique for assessing myocardial ischemia. With continuing interest on myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements, there is a requirement to fully appreciate the impact of technical aspects of the process. One such factor for rubidium-82 is prompt gamma compensation (PGC). This study aims to assess the impact of PGC on MBF and MFR calculated from dynamic Rb-82 data. Dynamic rest and stress images were acquired on a Siemens Biograph mCT and reconstructed with and without PGC in 50 patients (29 male). MBF and MFR were measured in the three main coronary territories as well as globally. With PGC, statistically significant reductions in MBF were observed in LAD (-6.9%), LCx (-4.8%), and globally (-6.5%) but only in obese patients. Significant increases in MBF were observed in RCA (+6.4%) in only nonobese patients. In very obese patients, differences of up to 40% in MBF were observed between PGC and non-PGC images. In nearly all cases, similar PGC differences were observed at stress and rest so there were no significant differences in MFR; however, in a small number of very obese patients, differences in excess of 20% were observed. PGC results in statistically significant changes in MBF, with the greatest reductions observed in the LAD and LCx territories of obese patients. In most cases, the impact on stress and rest data is of similar relative magnitudes and changes to MFR are small.

Two photon spectroscopy of rubidium atoms in a magneto-optic trap

International Nuclear Information System (INIS)

Fretel, E.

1997-01-01

Two photon transitions without doppler effect can be used as an atomic reference. The aim of this work is to study two photon transitions of rubidium atoms in a magneto-optical trap. The chosen transition is from the level 5 2 S 1/2 toward the level 5 2 D 5/2 . The magneto-optical trap is achieved by using 3 pairs of perpendicular laser beams and by setting a magnetic field gradient. About 10 18 atoms are trapped and cooled in a 1 mm 3 volume. In a first stage we have realized an optical double resonance experiment from the level 5 2 S 1/2 toward the level 5 2 D 5/2 by populating the intermediate level 5 2 P 3/2 . Then we have studied the two photon transition in this cluster of cold atoms. A particular setting of the experiment allows to reduce the effect of ray broadening and shifting due to the magnetic field of the trap

Identification of X-ray spectra in the Na-like to O-like rubidium ions in the range of 3.8-7.3 Angstroms

International Nuclear Information System (INIS)

Denis-Petit, D.; Bonnet, T.; Hannachi, F.; Gobet, F.; Tarisien, M.; Versteegen, M.; Comet, M.; Gosselin, G.; Meot, V.; Morel, P.; Pain, J.Ch.; Gilleron, F.; Frank, A.; Bagnoud, V.; Blazevic, A.; Dorchies, F.; Peyrusse, O.; Cayzac, W.; Roth, M.

2014-01-01

The X-rays emitted by a rubidium plasma source created by the PHELIX laser at an intensity of about 6*10"1"4 W/cm"2 were studied. The lines have been measured using Bragg crystals in the wavelength range between 3.8 and 7.3 Angstroms and identified by means of a numerical method developed to describe highly charged rubidium ions in LTE plasma. The experimental plasma temperature, density and charge state distributions have been estimated using non-LTE codes such as CHIVAS and AVERROES. The LTE plasma temperature and density used in the calculations are those allowing to reproduce the calculated NLTE charge state distribution. In order to optimize the use of computational resources, a criterion is established to select the configurations contributing most to the spectra among all those obtained in detailed level accounting based on the MCDF code. Seventy Rb-X-rays have been identified among which forty-nine are reported for the first time. The capabilities of our method are demonstrated by the good agreement of our identifications with previously published data when available. (authors)

Lithium, rubidium and cesium ion removal using potassium iron(III) hexacyanoferrate(II) supported on polymethylmethacrylate

International Nuclear Information System (INIS)

Shabana Taj; Din Muhammad; Ashraf Chaudhry, M.; Muhammad Mazhar

2011-01-01

Potassium iron(III) hexacyanoferrate(II) supported on poly methyl methacrylate, has been developed and investigated for the removal of lithium, rubidium and cesium ions. The material is capable of sorbing maximum quantities of these ions from 5.0, 2.5 and 4.5 M HNO 3 solutions respectively. Sorption studies, conducted individually for each metal ion, under optimized conditions, demonstrated that it was predominantly physisorption in the case of lithium ion while shifting to chemisorption with increasing ionic size. Distribution coefficient (K d ) values followed the order Cs + > Rb + > Li + at low concentrations of metal ions. Following these findings Cs + can preferably be removed from 1.5 to 5 M HNO 3 nuclear waste solutions. (author)

Analysis of the X-ray emission spectra of copper, germanium and rubidium plasmas produced at the Phelix laser facility

Science.gov (United States)

Comet, M.; Pain, J.-C.; Gilleron, F.; Piron, R.; Denis-Petit, D.; Méot, V.; Gosselin, G.; Morel, P.; Hannachi, F.; Gobet, F.; Tarisien, M.; Versteegen, M.

2017-03-01

We present the analysis of X-ray emission spectra of copper, germanium and rubidium plasmas measured at the Phelix laser facility. The laser intensity was around 6×1014 W.cm-2. The analysis is based on the hypothesis of an homogeneous plasma in local thermodynamic equilibrium using an effective temperature. This temperature is deduced from hydrodynamic simulations and collisional-radiative computations. Spectra are then calculated using the LTE opacity codes OPAMCDF and SCO-RCG and compared to experimental data.

Experimental study of linear magnetic dichroism in photoionization satellite transitions of atomic rubidium

International Nuclear Information System (INIS)

Jaenkaelae, K.; Alagia, M.; Feyer, V.; Richter, R.; Prince, K. C.

2011-01-01

Laser orientation in the initial state has been used to study the properties of satellite transitions in inner-shell photoionization of rubidium atoms. The linear magnetic dichroism in the angular distribution (LMDAD) has been utilized to probe the continuum waves of orbital angular momentum conserving monopole, and angular momentum changing conjugate satellites, accompanying the 4p ionization of atomic Rb. We show experimentally that LMDAD of both types of satellite transitions is nonzero and that LMDAD of monopole satellites, measured as a function of photon energy, mimics the LMDAD of direct photoionization, whereas the LMDAD of conjugate transitions deviates drastically from that trend. The results indicate that conjugate transitions cannot be described theoretically without explicit inclusion of electron-electron interaction. The present data can thus be used as a very precise test of current models for photoionization.

Fabrication and characterization of rubidium/formamidinium-incorporated methylammonium-lead-halide perovskite solar cells

Science.gov (United States)

Kato, Masataka; Suzuki, Atsushi; Ohishi, Yuya; Tanaka, Hiroki; Oku, Takeo

2018-01-01

Fabrication and characterization of perovskite solar cells using mesoporous TiO2 as an electron transporting layer and 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene as a hole-transporting layer were performed for improving the photovoltaic performance. Additive effects of formamidinium (FA), rubidium (Rb), chlorine (Cl) and bromine (Br) into the methylammonium-lead-halide perovskite crystal on the photovoltaic properties and microstructures were investigated. The photovoltaic parameters of short-circuit current density, conversion efficiency, the surface morphology and domain in the perovskite crystal were characterized. The slight addition of FACl and RbBr to the CH3NH3PbI3 crystal provided homogeneous microstructures with the dispersed crystal domains, which improved the photovoltaic performance. The excess addition of Cl to the perovskite crystal caused nanorod-like crystals, which degraded the photovoltaic performance.

Compact Optical Atomic Clock Based on a Two-Photon Transition in Rubidium

Science.gov (United States)

Martin, Kyle W.; Phelps, Gretchen; Lemke, Nathan D.; Bigelow, Matthew S.; Stuhl, Benjamin; Wojcik, Michael; Holt, Michael; Coddington, Ian; Bishop, Michael W.; Burke, John H.

2018-01-01

Extralaboratory atomic clocks are necessary for a wide array of applications (e.g., satellite-based navigation and communication). Building upon existing vapor-cell and laser technologies, we describe an optical atomic clock, designed around a simple and manufacturable architecture, that utilizes the 778-nm two-photon transition in rubidium and yields fractional-frequency instabilities of 4 ×10-13/√{τ (s ) } for τ from 1 to 10 000 s. We present a complete stability budget for this system and explore the required conditions under which a fractional-frequency instability of 1 ×10-15 can be maintained on long time scales. We provide a precise characterization of the leading sensitivities to external processes, including magnetic fields and fluctuations of the vapor-cell temperature and 778-nm laser power. The system is constructed primarily from commercially available components, an attractive feature from the standpoint of the commercialization and deployment of optical frequency standards.

Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons

International Nuclear Information System (INIS)

Lau, Ch.

2000-01-01

This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons

High resolution positron Q-value measurements and nuclear structure studies far from the stability line. Progress report

International Nuclear Information System (INIS)

Avignone, F.T. III.

1982-01-01

Research progress in briefly described, and details are presented in the attached preprints and reprints: (1) precision mass differences in light rubidium and krypton isotopes utilizing beta endpoint measurements; (2) precision mass measurements utilizing beta endpoints; (3) Monte Carlo calculations predicting the response of intrinsic GE detectors to electrons and positrons; and (4) reactor antineutrino spectra and nuclear spectroscopy of isotopes far from beta stability

Neutron powder diffraction and theory-aided structure refinement of rubidium and cesium ureate

Energy Technology Data Exchange (ETDEWEB)

Sterri, Kjersti B.; Deringer, Volker L.; Houben, Andreas; Jacobs, Philipp [RWTH Aachen Univ. (Germany). Inst. of Inorganic Chemistry; Kumar, Chogondahalli M.N. [Forschungszentrum Juelich GmbH, Juelich Centre for Neutron Science (JCNS), Outstation at SNS, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Oak Ridge National Laboratory, TN (United States). Chemical and Engineering Materials Div.; Dronskowski, Richard [RWTH Aachen Univ. (Germany). Inst. of Inorganic Chemistry; RWTH Aachen Univ. (Germany). Juelich-Aachen Research Alliance (JARA-HPC)

2016-08-01

Urea (CN{sub 2}H{sub 4}O) is a fundamental biomolecule whose derivatives are abundant throughout chemistry. Among the latter, rubidium ureate (RbCN{sub 2}H{sub 3}O) and its cesium analog (CsCN{sub 2}H{sub 3}O) have been described only very recently and form the first structurally characterized salts of deprotonated urea. Here, we report on a neutron diffraction study on the aforementioned alkaline-metal ureates, which affords the positions for all hydrogen atoms (including full anisotropic displacement tensors) and thus allows us to gain fundamental insights into the hydrogen-bonding networks in the title compounds. The structure refinements of the experimental neutron data proceeded successfully using starting parameters from ab initio simulations of atomic positions and anisotropic displacement parameters. Such joint experimental-theoretical refinement procedures promise significant practical potential in cases where complex solids (organic, organometallic, framework materials) are studied by powder diffraction.

Permian alkali granitoids of the transbaikal region (new Rb-Sr dates)

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, M K; Ryakhovskij, V M; Abramov, A V

1984-01-01

Rubidium-strontium isotopic investigations of granitoids from Khorinsk and Middle Oninsk massifs were conducted. Isochrones for two chief-modifications of rocks - subalkaline syenites and alkaline granites-were constructed. The age of syenites is determined to be (293 + 20) x 10/sup 6/ at (/sup 87/Sr//sup 86/Sr)/sub 0/=0.7044 +- 0.0106 that of alkaline granites - (253 +- 3) x 10/sup 6/ at (/sup 87/Sr//sup 86/Sr)/sub 0/=0.7077 +- 0.0033. Analytical data for determination of rubidium-strontium age of rocks of the mentioned massits are presented as well.

Atomic spin resonance in a rubidium beam obliquely incident to a transmission magnetic grating

International Nuclear Information System (INIS)

Hatakeyama, A; Goto, K

2016-01-01

We studied atomic spin resonance induced by atomic motion in a spatially periodic magnetostatic field. A rubidium atomic beam, with a velocity of about 400 m s −1 , was obliquely incident to a transmission magnetic grating that produced a spatially periodic magnetic field. The magnetic grating was formed by a magnetic thin film on a polyimide substrate that had multiple slits at 150 μm intervals. The atoms experienced field oscillation, depending on their velocity and the field period when passing through the grating, and underwent magnetic resonance. Resonance spectra obtained with a perpendicular magnetization film were in clear contrast to ones obtained with an in-plane magnetization film. The former exhibited resonance peaks at odd multiples of the frequency, determined by the velocity over the period, while the latter had dips at the same frequencies. (paper)

Thermodynamic Properties of Alkali Metal Hydroxides. Part II. Potassium, Rubidium, and Cesium Hydroxides

International Nuclear Information System (INIS)

Gurvich, L.V.; Bergman, G.A.; Gorokhov, L.N.; Iorish, V.S.; Leonidov, V.Y.; Yungman, V.S.

1997-01-01

The data on thermodynamic and molecular properties of the potassium, rubidium and cesium hydroxides have been collected, critically reviewed, analyzed, and evaluated. Tables of the thermodynamic properties [C p circ , Φ=-(G -H(0)/T, S, H -H(0), Δ f H, Δ f G)] of these hydroxides in the condensed and gaseous states have been calculated using the results of the analysis and some estimated values. The recommendations are compared with earlier evaluations given in the JANAF Thermochemical Tables and Thermodynamic Properties of Individual Substances. The properties considered are: the temperature and enthalpy of phase transitions and fusion, heat capacities, spectroscopic data, structures, bond energies, and enthalpies of formation at 298.15 K. The thermodynamic functions in solid, liquid, and gaseous states are calculated from T=0 to 2000 K for substances in condensed phase and up to 6000 K for gases. copyright 1997 American Institute of Physics and American Chemical Society

Magnetic resonance of rubidium atoms passing through a multi-layered transmission magnetic grating

International Nuclear Information System (INIS)

Nagata, Y; Kurokawa, S; Hatakeyama, A

2017-01-01

We measured the magnetic resonance of rubidium atoms passing through periodic magnetic fields generated by two types of multi-layered transmission magnetic grating. One of the gratings reported here was assembled by stacking four layers of magnetic films so that the direction of magnetization alternated at each level. The other grating was assembled so that the magnetization at each level was aligned. For both types of grating, the experimental results were in good agreement with our calculations. We studied the feasibility of extending the frequency band of the grating and narrowing its resonance linewidth by performing calculations. For magnetic resonance precision spectroscopy, we conclude that the multi-layered transmission magnetic grating can generate periodic fields with narrower linewidths at higher frequencies when a larger number of layers are assembled at a shorter period length. Moreover, the frequency band of this type of grating can potentially achieve frequencies of up to hundreds of PHz. (paper)

Structure determination, electronic and optical properties of rubidium holmium polyphosphate RbHo(PO3)4

Science.gov (United States)

Zhu, Jing; Chen, Hui; Wang, Yude; Guan, Hongtao; Xiao, Xuechun

2012-12-01

Structural, optical, and electronic properties of a new alkali metal-rare earth polyphosphate, RbHo(PO3)4, have been investigated by means of single-crystal X-ray diffraction, power X-ray diffraction, elemental analysis, and spectral measurement. RbHo(PO3)4 crystallizes in the monoclinic with space group P21/n and Z = 4. It is described as a three-dimensional (3D) architecture built up of PO4 double spiral chains and HoO8 polyhedra by corner-sharing. The 11-coordinated rubidium atoms are located in infinite tunnels. Additionally, in order to gain further insight into the relationship between property and structure of RbHo(PO3)4, theoretical calculation based on the density functional theory (DFT) was performed using the total-energy code CASTEP.

Skeletal muscle blood flow in vivo: detection with rubidium-82 and effects of glucose, insulin, and exercise

International Nuclear Information System (INIS)

Mossberg, K.A.; Mullani, N.; Gould, K.L.; Taegtmeyer, H.

1987-01-01

In order to assess the effects of glucose, insulin, and exercise on skeletal muscle blood flow in vivo, we measured positron emission from the thigh muscle of anesthetized rabbits after simultaneous aortic bolus injection of 82 Rb and radiolabeled microspheres (15 micron diameter). Estimates of flow with 82 Rb were based on first-pass regional extraction of 82 Rb by skeletal muscle. Flow estimates were made serially as a function of variations in plasma glucose and insulin and changing the muscle contractile state by electrical stimulation. Flow ranged from 3.1 ml/min/100 g at rest to 71 ml/min/100 g during stimulation. There was good agreement between the two methods of flow measurement over the entire range of flows (r = 0.96 at a slope of 0.90). Flow measured by either method did not vary significantly from baseline over a range of plasma glucose from 5 to 30 mM and plasma insulin from 0 to 20 microU/ml. When flow was increased up to 20-fold by electrical stimulation there was a decrease in extraction of 82 Rb proportional to the increase in flow. However, at pharmacologic levels of insulin (greater than 150 microU/ml) flow was increased twofold as measured by radiolabeled microspheres, but not as measured by rubidium. There was no apparent decrease in extraction of 82 Rb with high insulin. The discrepancy between the microsphere measured flow and rubidium measured flow with high plasma insulin levels can be explained by the assumption that the expected decrease in the extraction fraction was counteracted by an increase in Na+/K+-ATPase activity. It is concluded that the first-pass flow model gives valid estimates of skeletal muscle blood flow in vivo with 82 Rb, provided that plasma insulin levels are normal

The blue light indicator in rubidium 5S-5P-5D cascade excitation

Science.gov (United States)

Raja, Waseem; Ali, Md. Sabir; Chakrabarti, Alok; Ray, Ayan

2017-07-01

The cascade system has played an important role in contemporary research areas related to fields like Rydberg excitation, four wave mixing and non-classical light generation, etc. Depending on the specific objective, co or counter propagating pump-probe laser experimental geometry is followed. However, the stepwise excitation of atoms to states higher than the first excited state deals with increasingly much fewer number of atoms even compared to the population at first excited level. Hence, one needs a practical indicator to study the complex photon-atom interaction of the cascade system. Here, we experimentally analyze the case of rubidium 5S → 5P → 5D as a specimen of two-step excitation and highlight the efficacy of monitoring one branch, which emits 420 nm, of associated cascade decay route 5D → 6P → 5S, as an effective monitor of the coherence in the system.

Crystal structure of ammonium and rubidium octacyanomolybdates (4)

Energy Technology Data Exchange (ETDEWEB)

Semenishin, D.I.; Glovyak, T.; Mys' kiv, M.G.

1985-01-01

By the method of monocrystal at the automatic diffractometer ''Syntex P2/sub 1/'' the crystal structure of ammonium and rubidium octacyanomolybdates (4)-(NH/sub 4/)/sub 4/(Mo(CN)/sub 8/)x0.5H/sub 2/O (1) (sp.gr. Pma5 2, a=15.50(3), b=14.118 (3), c=7.438 (1)A, Z=4, R=0.062 and Rb/sub 4/(Mo(CN)/sub 8/):3H/sub 2/O (2) (sp.gr. P4/sub 1/2/sub 1/2, a=9.300 (1), c=21.807 (3) A, Z=4, R=0.065) is determined. Mo atoms in the structure 1 occupy two 2(b) and 2(c) particular positions and are surrounded, each of them, by light CN-ligands. The mean values of Mo-C distances for Mo(1) are equal 2.216, for Mo(2)-2.235 A. Mo-N mean values, practically are identical in both molybdenum anions and are equal 3.353 A. MoCN angles are varied from 175.0 to 178.4. The dodecahedron with the only symmetry axis 2 corresponds to the Mo(1) coordination sphere whereas the Mo(2) atoms coordination polyhedron (CP) is the symmetry in antiprism. In the structure 2 Mo-C distances are in the limits of 2.130-2.160 and Mo-N 3.290-3.307 A. MoCN angles are varied from 176.0 to 179.3 deg, the (MoC/sub 8/) CP represents a symmetry 2 dodecahedron. The existence of two Mo coordination forms in the structure 1 is up to now the only example among structurally studied octacyanomolybdates (4).

Traverse across the Nelspruit batholith and the geology of the excursion route between Sabie and Witbank

International Nuclear Information System (INIS)

Robb, L.J.; Anhaeusser, C.R.

1981-01-01

A geologic survey was done on the traverse across the Nelspruit batholith and the geology of the excursion route between Sabie and Witbank. Rubidium isotopes, strontium 86 and strontium 87 were used to determine the rock age. The petrogenetic aspects relating to the Nelspruit batholith were also studied

Elemental geochemistry and strontium-isotope stratigraphy of Cenomanian to Santonian neritic carbonates in the Zagros Basin, Iran

Science.gov (United States)

Navidtalab, Amin; Rahimpour-Bonab, Hossain; Huck, Stefan; Heimhofer, Ulrich

2016-12-01

A Neo-Tethyan upper Cenomanian-Santonian neritic carbonate ramp succession (Sarvak and Ilam formations), drilled in the Zagros Basin in southwest Iran, was investigated via detailed sedimentology, microfacies analysis, elemental geochemistry and Sr-isotope stratigraphy (SIS). The succession contains two exposure surfaces, which are known as the CT-ES and mT-ES (Cenomanian-Turonian and middle Turonian, respectively), and associated prominent negative carbon-isotope excursions that represent important regional stratigraphic marker horizons. Precise knowledge about the onset of platform exposure and the duration of the exposure-related hiatus, however, is currently lacking due to a rather low-resolved shallow-water biostratigraphic framework and a bulk carbonate carbon-isotope pattern that clearly differs from global Late Cretaceous reference curves. Therefore, the existing bio-chemostratigraphic framework was complemented by bulk carbonate strontium-isotope stratigraphy (SIS). As bulk carbonate material is in particular prone to diagenetic alteration, a careful selection of least altered samples has been carried out by means of elemental geochemistry and petrography. In contrast to what could be expected, the meteoric alteration of limestones beneath both exposure surfaces is not clearly expressed by increasing iron and manganese and coeval decreasing strontium contents. On the contrary, the impact of meteoric diagenesis is well illustrated via pronounced increases in Rb concentrations and concomitant prominent positive shifts to radiogenic strontium-isotope values, an observation that clearly reflects the decay of continentally derived 87Rb into 87Sr. Rubidium corrected strontium-isotope values place the CT-ES around the Cenomanian-Turonian boundary and point to an exposure duration of less than 0.4 Myr. This rather short-term CT-ES related hiatus is supported by petrographic evidence, which indicates a youth karstification stage of strata beneath the CT

Strontium isotopic study of sediment from the Ross Sea

International Nuclear Information System (INIS)

Kovach, J.; Faure, G.

1977-01-01

A preliminary report summarizing the results of a study of the strontium-87/strontium-86 ratios and of the rubidium and strontium concentrations of the fine-grained (less than 150 microns) noncarbonate fractions of sediment samples from core E32-25 raised from a depth of 327 fathoms in the Ross Sea at 78 0 31.0'S 164 0 24.7'W was presented. The strontium-87/strontium-86 ratios of the samples analyzed range from 0.7119 to 0.7220. Rubidium and strontium concentrations range, respectively, from 126 to 164 parts per million and from 113 to 174 parts per million. The observed strontium-87/strontium-86 ratios and strontium concentrations in sediment samples from core E32-25 fit a hyperbolic curve. These ratios can be used to estimate the concentrations of volcanogenic detritus in the sediment samples. The results of this study provide additional baseline data for anticipated future studies of sediment cores to be recovered from beneath the Ross Ice Shelf by the Ross Ice Shelf Project. 1 figure

Light-Shifts of an Integrated Filter-Cell Rubidium Atomic Clock

Science.gov (United States)

2015-05-25

the light-shift coefficient for two different rf- discharge lamps (i.e., a pure 87Rb lamp and a lamp filled with the natural Rb isotope abundance...for the Galileo Rb clock under the assumption of a natural (or 85Rb isotopically enriched) rf- discharge lamp for the Galileo clock. I...satellites [14]. 6.8347… GHz 85Rb Filter Cell Cell Resonance Photodiode Microwave Cavity 87Rb Discharge Lamp 87Rb & N2 Rb & Xe, Kr Optical Pumping 87Rb

Myocardial perfusion of infarcted and normal myocardium in propofol-anesthetized minipigs using ⁸²Rubidium PET

DEFF Research Database (Denmark)

Rasmussen, Thomas; Larsen, Bjarke Follin; Kastrup, Jens

2016-01-01

Cardiac Rubidium-82 (82Rb) positron-emission-tomography (PET) is a good method for quantification of myocardial blood flow in man. Quantification of myocardial blood flow in animals to evaluate new treatment strategies or to understand underlying disease is also of great interest but raises some...... challenges. Animals, which have been anesthetized during PET acquisition, might react differently to used stress medications, and therefore difficulties might exist while evaluating the resulting PET images using standard software packages from commercial vendors optimized for human hearts. Furthermore...... propofol, used for anesthesia, can influence myocardial perfusion and coronary flow reserve due to its vasorelaxant effect, and interactions might exist between propofol and used stress agents, potentially affecting the result of the examination. We present cardiac 82Rb-PET studies performed in propofol...

Promotion of radiation peroxidation in models of lipid membranes by caesium and rubidium counter-ions: micellar linolenic acids

Energy Technology Data Exchange (ETDEWEB)

Raleigh, J A; Kremers, W [Atomic Energy of Canada Ltd., Pinawa, Manitoba. Whiteshell Nuclear Research Establishment

1978-11-01

Caesium and rubidium counter-ions increase peroxidation in irradiated micelles of linoleic (18 : 2) and linolenic (18 :3) acids. The effect was specific to Cs/sup +/ and Rb/sup +/ in the alkali metal series. The effect was independent of the salts used (Cl/sup -/, NO/sub 3//sup -/, Cl0/sub 4//sup -/) and, therefore, independent of the chaotropic nature, and reactivity with hydroxyl radicals of Cl/sup -/, NO/sub 3//sup -/ and ClO/sub 4//sup -/. The promotion of peroxidation by Cs/sup +/ and Rb/sup +/ is interpreted in terms of their effect on fatty acid micelle structure. The dependence of radiation peroxidation on lipid structure in the micelles may be significant for studies of peroxidation in highly structured cell membranes.

Atomic rubidium, the workhorse of theoretical collision physics

NARCIS (Netherlands)

Verhaar, B.; van Kempen, E.; Kokkelmans, S.J.J.M.F.

2008-01-01

Since the first realizations of Bose-Einstein condensates in ultracold atomic gases in 1995, the 85Rb and 87Rb atomic species have acted as the workhorses of experimental developments in this field. Parallel to and partly preceding this work the same isotopes figured also as workhorses for

Effect of optical pumping on absorption spectra for the doppler broadened rubidium

International Nuclear Information System (INIS)

Shin, Seo Ro; Noh, Heung Ryoul

2008-01-01

The absorption of a laser beam in the Doppler broadened atomic vapor cell is one of the simplest problems in atomic physics. Although many reports on theoretical and experimental studies of linear absorption have been reported, the effect of optical pumping on the absorption coefficient has not been studied in detail. In this presentation, we present a theoretical and experimental study on linear absorption for the Doppler broadened rubidium vapor cell. The absorption coefficient of a σ"+"(or π)polarized laser beam was calculated as a function of the laser frequency for the various laser intensities. The calculated results were compared with the experimental results. Figure 1(a) shows the calculated absorption coefficient of the π polarized laser beam for the transition F"g"=1→F"e"=0,1,2 of the "87"Rb atom. The diameter of the laser beam was 3mm and the intensity was I=0 and I=0.1I"8"(I"8"=16.2W/m"2"). The peak values for various intensities are shown in Fig. 1(b). We found that the absorption coefficient for the transition from the lower hyperfine state decreased with the increased laser intensity, whereas that for the transition from the upper hyperfine state increased(decreased)for the σ"+"(π)polarized laser beam

Rubidium contents in erythrocyte of children, rice and soil in the areas with different selenium status

International Nuclear Information System (INIS)

Liu Nianqing; Zhao Shunying; Qian Qinfang; Zhu Lianzhen; Piao Jianhua

1997-01-01

Rubidium concentration of erythrocyte of healthy children aged from 6-11 years living in four areas of Sichuan Province with different selenium status was measured by PIXE and the results show that the Rb concentration in erythrocyte for the Keshan Disease area is two times more than other three areas. Meanwhile the glutathione peroxidase (GSHPx) activity of erythrocyte was determined and the results confirm that children in the Keshan Disease area are really with selenium deficiency. The Rb contents in rice and soil samples from the Keshan Disease area and the Se-deficiency area but with Se-supplementation to the inhabitants, were tested by INNA. It was found that Rb contents in rice and soil from the former area were much higher than those from the latter. This result indicates that Rb in erythrocyte of children is mainly taken from staple food (rice) and that a higher Rb level in soil is probably another environmental factor causing the Keshan Disease

Rb-Sr whole-rock and mineral ages, K-Ar, 40Ar/39Ar, and U-Pb mineral ages, and strontium, lead, neodymium, and oxygen isotopic compositions for granitic rocks from the Salinian Composite Terrane, California:

Science.gov (United States)

Kistler, R.W.; Champion, D.E.

2001-01-01

This report summarizes new and published age and isotopic data for whole-rocks and minerals from granitic rocks in the Salinian composite terrane, California. Rubidium-strontium whole-rock ages of plutons are in two groups, Early Cretaceous (122 to 100 Ma) and Late Cretaceous (95 to 82 Ma). Early Cretaceous plutons occur in all granitic rock exposures from Bodega Head in the north to those from the Santa Lucia and Gabilan Ranges in the central part of the terrane. Late Cretaceous plutons have been identified in the Point Reyes Peninsula, the Santa Lucia and the Gabilan Ranges, and in the La Panza Range in the southern part of the terrane. Ranges of initial values of isotopic compositions are 87Sr/86Sr, 0.7046-0.7147, δ18O, +8.5 to +12.5 per mil, 206Pb/204Pb, 18.901-19.860, 207Pb/204Pb, 15.618-15.814, 208Pb/204Pb, 38.569- 39.493, and εNd, +0.9 to -8.6. The initial 87Sr/86Sr=0.706 isopleth is identified in the northern Gabilan Range and in the Ben Lomond area of the Santa Cruz Mountains, in Montara Mountain, in Bodega Head, and to the west of the Farallon Islands on the Cordell Bank. This isotopic boundary is offset about 95 miles (160km) by right-lateral displacements along the San Gregorio-Hosgri and San Andreas fault systems.

Application of the isotopic index in isotope geochemical investigation

International Nuclear Information System (INIS)

Schuetze, H.

1982-06-01

A method is described which allows to calculate approximately isotope exchange equilibria between different crystalline silicates. The algorithm uses a newly introduced isotopic index. It is defined using isotopic increments of the variant types of silicatic bonds. This isotopic index gives a quantitative measure of the ability to enrich 18 O or 30 Si, respectively. The dependence of isotopic fractionations on temperature can be calculated approximately by means of the isotopic index, too. On this theoretical base some problems of magmatism and two varieties of an isotope geochemical model of the evolution of the Earth's crust are treated. Finally, the possibility is demonstrated to give prognostic statements about the likelihood of ore bearing of different granites. (author)

The isotopic contamination in electromagnetic isotope separators; La contagion isotopique dans les separateurs electromagnetiques d'isotopes

Energy Technology Data Exchange (ETDEWEB)

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

1959-07-01

In the early years of isotope separation, and in particular electromagnetic isotope separation, needs for rapid results have conducted to empiric research. This paper describes fundamental research on the electromagnetic isotope separation to a better understanding of isotope separators as well as improving the performances. Focus has been made on the study of the principle of isotope contamination and the remedial action on the separator to improve the isotope separation ratio. In a first part, the author come back to the functioning of an electromagnetic separator and generalities on isotope contamination. Secondly, it describes the two stages separation method with two dispersive apparatus, an electromagnetic separation stage followed by an electrostatic separation stage, both separated by a diaphragm. The specifications of the electrostatic stage are given and its different settings and their consequences on isotope separation are investigated. In a third part, mechanisms and contamination factors in the isotope separation are discussed: natural isotope contamination, contamination by rebounding on the collector, contamination because of a low resolution, contamination by chromatism and diffusion effect, breakdown of condenser voltage. Analysis of experimental results shows the diffusion as the most important contamination factor in electromagnetic isotope separation. As contamination factors are dependent on geometric parameters, sector angle, radius of curvature in the magnetic field and clearance height are discussed in a fourth part. The better understanding of the mechanism of the different contamination factors and the study of influential parameters as pressure and geometric parameters lead to define a global scheme of isotope contamination and determinate optima separator design and experimental parameters. Finally, the global scheme of isotope contamination and hypothesis on optima specifications and experimental parameters has been checked during a

Isotopically modified compounds

International Nuclear Information System (INIS)

Kuruc, J.

2009-01-01

In this chapter the nomenclature of isotopically modified compounds in Slovak language is described. This chapter consists of following parts: (1) Isotopically substituted compounds; (2) Specifically isotopically labelled compounds; (3) Selectively isotopically labelled compounds; (4) Non-selectively isotopically labelled compounds; (5) Isotopically deficient compounds.

Isotope effect and isotope separation. A chemist's view

International Nuclear Information System (INIS)

Ishida, Takanobu

2002-01-01

What causes the isotope effects (IE)? This presentation will be centered around the equilibrium isotope effects due to the differences in the nuclear masses. The occurrence of the equilibrium constant, K, of isotope exchange reactions which differ from the values predicted by the classical theory of statistical mechanics, K cl , is explored. The non-classical K corresponds to the unit-stage separation factor, α, that is different from unity and forms a basis of an isotope separation process involving the chemical exchange reaction. Here, the word 'chemical exchange' includes not only the isotope exchange chemical reactions between two or more chemical species but also the isotope exchanges involving the equilibria between liquid and vapor phases and liquid-gas, liquid solution-gas, liquid-liquid, and solid-liquid phases. In Section I, origins of the isotope effect phenomena will be explored and, in the process, various quantities used in discussions of isotope effect that have often caused confusions will be unambiguously defined. This Section will also correlate equilibrium constant with separation factor. In Section II, various forms of temperature-dependence of IE and separation factor will be discussed. (author)

Distrinution and properties of nuclides in fission by means of on-line isotope separation

International Nuclear Information System (INIS)

Nir-El, Y.

1977-07-01

This work determines the independent yield distribution fo the alkali elements' fission products. The results were analyzed by especially developed equations and half-lives were calculated using a computer program which fits a series of exponentials to the activity decay curve by the least squares method. Independent yields were determined by use of calculated correction factors and by normalization against a known independent yield. The three nuclides 147 Ba, 148 Ba, and 149 La were indentified fot the first time in this work and their half-lives were determined Comparison with calculated values, within the framework of beta decay theory, gave in all cases agreement better than an order of magnitude. Extrapolation of the experimental curve and prediction of values which have not yet been measured are now possible. Independent yield distributions of rubidium and cesium include values for 99 Rb, 147 Cs and 148 Cs determined for the first time. The last two isotopes were identified fot the first time in the present work. A model was developed to interpretthe heavy wing phenomenon based on statistical considerations and onbasic properties of prompt neutron emission in fission. The width parameter of the independent yield distribution calculated according to the propsed model is in very good agreement with the width parameter of a Gaussian fitted to the measured distribution. (B.G.)

Rb-Sr age estimation of granites-gneisses of Belopotokskij type (Soviet Carpathians)

International Nuclear Information System (INIS)

Stepanyuk, L.M.; Kotlovskaya, F.I.; Dovbush, T.I.

1987-01-01

Using rubidium-strontium method the age of granito-gneisses of Belopotokskij type of 470 ± 6 mln. years, which agree with isotopic age (459 ± 6 mln. years) obtained by uranium-lead isochronous method using syngenetic zircon, is established. The latter testifies to the manifestation of magmatic activity 460-470 mln. years ago. The low initial ratio of strontium isotopes 87 Sr/ 86 Sr and results of petrographic study of fel spars are indicative of magmatic nature of initial granites and plutonic (mantle or lower crust) source of magma, crystallization of which was the beginning of the Belopotokskij type granito-gneiss formation

The isotopic contamination in electromagnetic isotope separators; La contagion isotopique dans les separateurs electromagnetiques d'isotopes

Energy Technology Data Exchange (ETDEWEB)

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

1959-07-01

In the early years of isotope separation, and in particular electromagnetic isotope separation, needs for rapid results have conducted to empiric research. This paper describes fundamental research on the electromagnetic isotope separation to a better understanding of isotope separators as well as improving the performances. Focus has been made on the study of the principle of isotope contamination and the remedial action on the separator to improve the isotope separation ratio. In a first part, the author come back to the functioning of an electromagnetic separator and generalities on isotope contamination. Secondly, it describes the two stages separation method with two dispersive apparatus, an electromagnetic separation stage followed by an electrostatic separation stage, both separated by a diaphragm. The specifications of the electrostatic stage are given and its different settings and their consequences on isotope separation are investigated. In a third part, mechanisms and contamination factors in the isotope separation are discussed: natural isotope contamination, contamination by rebounding on the collector, contamination because of a low resolution, contamination by chromatism and diffusion effect, breakdown of condenser voltage. Analysis of experimental results shows the diffusion as the most important contamination factor in electromagnetic isotope separation. As contamination factors are dependent on geometric parameters, sector angle, radius of curvature in the magnetic field and clearance height are discussed in a fourth part. The better understanding of the mechanism of the different contamination factors and the study of influential parameters as pressure and geometric parameters lead to define a global scheme of isotope contamination and determinate optima separator design and experimental parameters. Finally, the global scheme of isotope contamination and hypothesis on optima specifications and experimental parameters has been checked during a

Isotopic shift in even-even barium isotopes

International Nuclear Information System (INIS)

Karim, Afaque; Naz, Tabassum; Ahmad, Shakeb

2017-01-01

We have discussed the correlation between a nuclear shape and its matter distribution. Here, we present the root-mean-square radii (r rms ) and rms charge radius (r ch ). We have also discussed the isotopic shift in terms of the observable ‹Δr 2 c › N,82 and its differential ‹Δr 2 c › N-2,N . We present nuclear radii evaluated using different interactions. Neutron radii and charge radii for all the isotopic chains are shown. Neutron radii for Ba isotopes show an increasing trend with the neutron number for all isotopic chains. One can observe a clear kink about magic number N=82

Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons; Etude de la production de faisceaux riches en neutrons par fission induite par neutrons rapides

Energy Technology Data Exchange (ETDEWEB)

Lau, Ch

2000-09-15

This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons.

Stable isotopes

International Nuclear Information System (INIS)

Evans, D.K.

1986-01-01

Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

Uranium Isotopic Analysis with the FRAM Isotopic Analysis Code

International Nuclear Information System (INIS)

Vo, D.T.; Sampson, T.E.

1999-01-01

FRAM is the acronym for Fixed-Energy Response-Function Analysis with Multiple efficiency. This software was developed at Los Alamos National Laboratory originally for plutonium isotopic analysis. Later, it was adapted for uranium isotopic analysis in addition to plutonium. It is a code based on a self-calibration using several gamma-ray peaks for determining the isotopic ratios. The versatile-parameter database structure governs all facets of the data analysis. User editing of the parameter sets allows great flexibility in handling data with different isotopic distributions, interfering isotopes, and different acquisition parameters such as energy calibration and detector type

Interaction of xenone difluoride with the fluorocomplexes of lanthanides and rubidium of the Rb3M3F6 composition

International Nuclear Information System (INIS)

Goryachenkov, S.A.; Fadeeva, N.E.; Kiselev, Yu.M.; Martynenko, L.I.; Spitsyn, V.I.

1984-01-01

The possibility of preparing rubidium fluorocomplexes of tetravalent lanthanides of the Rb 3 M 4 F 7 composition from Rb 3 M 3 F 6 (M 3 =Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb) with XeF 2 has been studied. By the DTA method it is shown that Ce and Pr salts are fluorinated respectively at approximately 100 and approximately 235 deg C with a noticeable exoeffect. Tb and Dy salts fluorination proceeds with considerable kinetic difficulties. The fluorination products composition, Rb 3 M 4 F 7 (M 4 =Ce, Pr, Tb, Dy) is confirmed by the methods of chemical, IR-spectroscopic and X-ray phase analyses. XeF 2 interaction with Rb 3 M 3 F 6 salts of other lanthanides up to 400 deg C has not been observed

Isotope enrichment

International Nuclear Information System (INIS)

Garbuny, M.

1979-01-01

The invention discloses a method for deriving, from a starting material including an element having a plurality of isotopes, derived material enriched in one isotope of the element. The starting material is deposited on a substrate at less than a critical submonatomic surface density, typically less than 10 16 atoms per square centimeter. The deposit is then selectively irradiated by a laser (maser or electronic oscillator) beam with monochromatic coherent radiation resonant with the one isotope causing the material including the one istope to escape from the substrate. The escaping enriched material is then collected. Where the element has two isotopes, one of which is to be collected, the deposit may be irradiated with radiation resonant with the other isotope and the residual material enriched in the one isotope may be evaporated from the substrate and collected

Demonstration of a diode-laser-based high spectral resolution lidar (HSRL) for quantitative profiling of clouds and aerosols.

Science.gov (United States)

Hayman, Matthew; Spuler, Scott

2017-11-27

We present a demonstration of a diode-laser-based high spectral resolution lidar. It is capable of performing calibrated retrievals of aerosol and cloud optical properties at a 150 m range resolution with less than 1 minute integration time over an approximate range of 12 km during day and night. This instrument operates at 780 nm, a wavelength that is well established for reliable semiconductor lasers and detectors, and was chosen because it corresponds to the D2 rubidium absorption line. A heated vapor reference cell of isotopic rubidium 87 is used as an effective and reliable aerosol signal blocking filter in the instrument. In principle, the diode-laser-based high spectral resolution lidar can be made cost competitive with elastic backscatter lidar systems, yet delivers a significant improvement in data quality through direct retrieval of quantitative optical properties of clouds and aerosols.

Isotope anomalies in oxygen isotope exchange equilibrium systems

International Nuclear Information System (INIS)

Kotaka, M.

1997-01-01

The purpose of the present work is to elucidate the isotope anomalies in oxygen isotope exchange equilibrium systems, according to the calculations of the equilibrium constants for oxygen isotopic exchange reactions, and the calculations of the oxygen isotope separation factors between two phases. The equilibrium constants (K65, K67, K68 and K69) of 16 O- 15 O, 16 O 17 O, 16 O- 18 O, and 16 O- 19 O exchange reactions between diatomic oxides were calculated in a wide temperature range on the basis of quantum statistical mechanics. Many equilibrium constants showed the anomalous mass effects, and then had the crossover temperatures and the mass independent fractionation (MIF) temperatures which held K67 = K65, K67 = K68, or K67 = K69, etc. For example, the equilibrium constants for the reactions between OH and the other diatomic oxides (MO) showed the anomalous mass effects, when M was Li, Na, Mg, K, Fe, Al, Ge, Zr, Pt, etc. The 16 O 15 O, 16 O 17 O, 16 O- 18 O, and 16 O- 19 O oxygen isotope separation factors (S65, S67, S68 and S69) between two phases were calculated, when OH and CO were in the first phase, and SiO was in the second phase. Although the oxygen isotopic exchange equilibria in the two phases had no MIF and crossover temperatures, the separation factors showed the anomalous mass effects and had the temperatures. According to what is called the normal mass effects for the equilibrium constant of isotopic exchange reaction, the value of InK68/InK67 is 1.885. Therefore, the value of InS68/InS67 should be 1.885 too. The value calculated, however, widely changed. It can be concluded from the results obtained in the present work that some oxygen isotopic exchange equilibria cause the anomalous mass effects, the anomalous oxygen isotope separation factors, and then isotope anomalies

Methane clumped isotopes: Progress and potential for a new isotopic tracer

Energy Technology Data Exchange (ETDEWEB)

Douglas, Peter M. J.; Stolper, Daniel A.; Eiler, John M.; Sessions, Alex L.; Lawson, Michael; Shuai, Yanhua; Bishop, Andrew; Podlaha, Olaf G.; Ferreira, Alexandre A.; Santos Neto, Eugenio V.; Niemann, Martin; Steen, Arne S.; Huang, Ling; Chimiak, Laura; Valentine, David L.; Fiebig, Jens; Luhmann, Andrew J.; Seyfried, William E.; Etiope, Giuseppe; Schoell, Martin; Inskeep, William P.; Moran, James J.; Kitchen, Nami

2017-11-01

The isotopic composition of methane is of longstanding geochemical interest, with important implications for understanding hydrocarbon systems, atmospheric greenhouse gas concentrations, the global carbon cycle, and life in extreme environments. Recent analytical developments focusing on multiply substituted isotopologues (‘clumped isotopes’) are opening a potentially valuable new window into methane geochemistry. When methane forms in internal isotopic equilibrium, clumped isotopes can provide a direct record of formation temperature, making this property particularly valuable for identifying different methane origins. However, it has also become clear that in certain settings methane clumped isotope measurements record kinetic rather than equilibrium isotope effects. Here we present a substantially expanded dataset of methane clumped isotope analyses, and provide a synthesis of the current interpretive framework for this parameter. We review different processes affecting methane clumped isotope compositions, describe the relationships between conventional isotope and clumped isotope data, and summarize the types of information that this measurement can provide in different Earth and planetary environments.

Isotope separation

International Nuclear Information System (INIS)

Eerkens, J.W.

1979-01-01

A method of isotope separation is described which involves the use of a laser photon beam to selectively induce energy level transitions of an isotope molecule containing the isotope to be separated. The use of the technique for 235 U enrichment is demonstrated. (UK)

Optical spectroscopy of rubidium Rydberg atoms with a 297 nm frequency doubled dye laser

International Nuclear Information System (INIS)

Becker, Th.; Germann, Th.; Thoumany, P.; Stania, G.; Urbonas, L.; Haensch, T.

2008-01-01

Full text: Rydberg atoms have played an important role in atomic physics and optical spectroscopy since many years. Due to their long lifetime and the big dipole matrix element between neighbouring Rydberg levels they are an essential tool in microwave cavity-qed experiments. Ultracold Rydberg gases are a promising candidate for realizing controlled quantum gates in atomic ensembles. In most experiments Rydberg atoms are detected destructively, where the optically excited atoms are first ionized followed by an electronic detection of the ionization products. A Doppler-free purely optical detection was reported in a room temperature cell and in an atomic beam apparatus using the technique of electromagnetically induced transparency. In all these experiments the Rydberg atoms are excited with two lasers in a two-step ladder configuration. Here we show that Doppler-free purely optical spectroscopy is also possible with a one step excitation scheme involving a UV laser at 297 nm. We excite the 85 Rb isotope from the 5S 1/2 ground state to the 63P 3/2 state with a frequency doubled dye laser in a room temperature gas cell without buffer gas. Rydberg transitions are detected by monitoring the absorption of 780 nm laser light which is superimposed on the UV light and resonant with one hyperfine component of the Rubidium D2 line. With these two lasers we realize a V-scheme and utilize the quantum amplification effect due to the different natural lifetimes of the upper levels of the two transitions: an excitation into the 63P level hinders many absorption-emission cycles of the D2 transition and leads to a reduced absorption on that line. We discuss the shape of the observed spectra in the context of electron shelving and EIT experiments. By applying a frequency modulation to the UV laser, we can obtain dispersive signals which can be used to stabilize the laser to a specific Rydberg transition. By shifting the frequency of the 780 nm laser to crossover resonances in the

Generator-produced rubidium-82 positron emission tomography myocardial perfusion imaging. From basic aspects to clinical applications

International Nuclear Information System (INIS)

Yoshinaga, Keiichiro; Klein, R.; Tamaki, Nagara

2010-01-01

Cardiovascular disease is the leading cause of death in modern industrialized countries with an aging population. This fact has fueled the need for innovative diagnostic testing intended to improve coronary artery disease (CAD) patient care. Detection of myocardial ischemia using myocardial perfusion imaging (MPI) plays an important role for CAD diagnosis and the prediction of future risk of cardiovascular events. Positron emission tomography (PET) MPI has high diagnostic accuracy and can estimate regional myocardial blood flow (MBF) in patients with CAD. Rubidium-82 ( 82 Rb) is a generator-produced PET myocardial perfusion tracer and has been widely used in North America in clinical practice. 82 Rb PET has recently become available in some cardiovascular centers in Europe and Japan. Clinical trials are expected in both regions. 82 Rb PET has high diagnostic accuracy and recent data have shown its prognostic value. Thus, 82 Rb PET would greatly contribute to CAD patients' care. 82 Rb PET can also be used to quantify MBF. This review describes the current status of 82 Rb MPI from basic principles to clinical implications. This paper also highlights the recent development of MBF quantification using 82 Rb PET. (author)

Data on inelastic processes in low-energy potassium-hydrogen and rubidium-hydrogen collisions

Science.gov (United States)

Yakovleva, S. A.; Barklem, P. S.; Belyaev, A. K.

2018-01-01

Two sets of rate coefficients for low-energy inelastic potassium-hydrogen and rubidium-hydrogen collisions were computed for each collisional system based on two model electronic structure calculations, performed by the quantum asymptotic semi-empirical and the quantum asymptotic linear combinations of atomic orbitals (LCAO) approaches, followed by quantum multichannel calculations for the non-adiabatic nuclear dynamics. The rate coefficients for the charge transfer (mutual neutralization, ion-pair formation), excitation and de-excitation processes are calculated for all transitions between the five lowest lying covalent states and the ionic states for each collisional system for the temperature range 1000-10 000 K. The processes involving higher lying states have extremely low rate coefficients and, hence, are neglected. The two model calculations both single out the same partial processes as having large and moderate rate coefficients. The largest rate coefficients correspond to the mutual neutralization processes into the K(5s 2S) and Rb(4d 2D) final states and at temperature 6000 K have values exceeding 3 × 10-8 cm3 s-1 and 4 × 10-8 cm3 s-1, respectively. It is shown that both the semi-empirical and the LCAO approaches perform equally well on average and that both sets of atomic data have roughly the same accuracy. The processes with large and moderate rate coefficients are likely to be important for non-LTE modelling in atmospheres of F, G and K-stars, especially metal-poor stars.

Isotopic separation

International Nuclear Information System (INIS)

Castle, P.M.

1979-01-01

This invention relates to molecular and atomic isotope separation and is particularly applicable to the separation of 235 U from other uranium isotopes including 238 U. In the method described a desired isotope is separated mechanically from an atomic or molecular beam formed from an isotope mixture utilising the isotropic recoil momenta resulting from selective excitation of the desired isotope species by radiation, followed by ionization or dissociation by radiation or electron attachment. By forming a matrix of UF 6 molecules in HBr molecules so as to collapse the V 3 vibrational mode of the UF 6 molecule the 235 UF 6 molecules are selectively excited to promote reduction of UF 6 molecules containing 235 U and facilitate separation. (UK)

Application of heavy stable isotopes in forensic isotope geochemistry: A review

International Nuclear Information System (INIS)

Aggarwal, Jugdeep; Habicht-Mauche, Judith; Juarez, Chelsey

2008-01-01

Light stable isotopes have been used for many years to characterize the source and transport of materials. More recently heavy isotope systems such as Sr, Nd and Pb have been added to this list in order to aid source identification. With the advent of multiple collector ICP-MS, the range of isotopic tools now available has increased considerably, however, until the isotope systematics of these new non-traditional isotope systems have become better understood, they will not be as useful in characterizing material source and transportation. Applications using heavy metal stable isotopes (mostly traditional heavy isotopes) have reached most avenues in science, including earth sciences, archaeology, anthropology, animal physiology, ecology and toxicology. This field will continue to grow as new applications are developed and techniques become simpler and quicker. This paper provides a review of how this field has grown and presents two new applications using Pb and Sr isotopes in glazes to determine the source of ore used in glazes, and using Sr isotopes to determine the origin of undocumented deceased Mexican border crossers

Application of heavy stable isotopes in forensic isotope geochemistry: A review

Energy Technology Data Exchange (ETDEWEB)

Aggarwal, Jugdeep [W.M. Keck Isotope Laboratory, Department of Earth Sciences, University of California, Santa Cruz, CA 95064 (United States)], E-mail: jaggarwal@pmc.ucsc.edu; Habicht-Mauche, Judith; Juarez, Chelsey [Department of Anthropology, University of California, Santa Cruz, CA 95064 (United States)

2008-09-15

Light stable isotopes have been used for many years to characterize the source and transport of materials. More recently heavy isotope systems such as Sr, Nd and Pb have been added to this list in order to aid source identification. With the advent of multiple collector ICP-MS, the range of isotopic tools now available has increased considerably, however, until the isotope systematics of these new non-traditional isotope systems have become better understood, they will not be as useful in characterizing material source and transportation. Applications using heavy metal stable isotopes (mostly traditional heavy isotopes) have reached most avenues in science, including earth sciences, archaeology, anthropology, animal physiology, ecology and toxicology. This field will continue to grow as new applications are developed and techniques become simpler and quicker. This paper provides a review of how this field has grown and presents two new applications using Pb and Sr isotopes in glazes to determine the source of ore used in glazes, and using Sr isotopes to determine the origin of undocumented deceased Mexican border crossers.

Absolute experimental cross sections for the electron impact ionization of rubidium. Technical summary report

International Nuclear Information System (INIS)

Hughes, D.W.; Feeney, R.K.

1980-01-01

The absolute cross sections for the double, triple, and quadruple ionization of Rb + ions by electron impact have been measured from below their respective thresholds to approximately 3000 eV. This determination has been accomplished using a crossed beam facility in which monoenergetic beams of ions and electrons are caused to intersect at right angles in a well-defined collision volume. Multiply charged, product ions born as a result of the electron impact are deflected into their respective detectors by cascaded electrostatic analyzers. The multiply charged beam current component is measured by means of a vibrating reed electrometer operating in the rate-of-charge mode. The required singly charged rubidium ions are produced in a thermionic ion source and pass through a series of focusing, collimating and deflecting structures before entering the interaction region. A thermionically generated, rectangular electron beam intercepts the target ions in a spatially designated collision volume. Just prior to entering this interaction region the two beams can be made to pass through a movable slit scanner which determines their spatial profiles. The various charged particle currents, energies and beam current density distributions represent the experimental data from which the desired absolute cross sections have been determined. The results obtained with this technique are compared with available theoretical predictions of the appropriate cross sections

Photo-induced charge-transfer phase transition of rubidium manganese hexacyanoferrate in ferromagnetic and paramagnetic states

International Nuclear Information System (INIS)

Tokoro, Hiroko; Hashimoto, Kazuhito; Ohkoshi, Shin-ichi

2007-01-01

A charge transfer phase transition with thermal hysteresis loop is observed in a series of rubidium manganese hexacyanoferrates, RbMn[Fe(China) 6 ] (1), Rb 0.88 Mn[Fe(China) 6 ] 0.96 .0.6H 2 O (2), and Rb 0.97 Mn[Fe(China) 6 ] 0.99 .0.2H 2 O (3). This phase transition is accompanied by a structural change from cubic (F4-bar 3m) to tetragonal (I4-bar m2). Its high-temperature (HT) and low-temperature (LT) phases are composed of Mn II (S=2/5)NC-Fe III (S=1/2) and Mn III (S=2)-NC-Fe II (S=0), respectively. The phase transition is caused by a metal-to-metal charge transfer from Mn II to Fe III and a Jahn-Teller distortion of the produced Mn III ion. At the ferromagnetic state in LT phase of 2, the photo-induced phase transition is observed, i.e., magnetization is quenched by the irradiation with only one shot of laser pulse. This phenomenon is caused by a photo-induced phase transition from the LT phase to the HT phase. In 3, optical switching between LT and HT phases at room temperature in paramagnetic region is observed

Pyroelectric Properties of Potassium and Rubidium Titanyl-Arsenate Single Crystals in the Temperature Range of 4.2-300 K

International Nuclear Information System (INIS)

Shaldin, Yu. V.; Matyjasik, S.; Novikova, N. E.; Tseitlin, M.; Mozhaev, E.; Roth, M.

2010-01-01

The temperature dependences of the pyroelectric coefficients of KTiOAsO 4 and RbTiOAsO 4 single crystals grown by flux crystallization have been investigated in the temperature range of 4.2-300 K. With an increase in temperature, superionic conductivity first arises in KTiOAsO4 (at T > 200 K) and then (at T > 270 K) in RbTiOAsO 4 . This conductivity is much higher in the samples polarized at T = 4.2 K. An exponential change in the crystal resistivity along the polar direction is simultaneously observed. The results of measurements in the range of 4.2-200 K indicate larger values of pyroelectric coefficients when compared with potassium and rubidium titanyl-phosphate crystals. A correlation between the pyroelectric coefficients and a change in the lattice constants at isomorphic substitutions of K atoms for Rb and P atoms for As has been revealed within the symmetry approach.

Pyroelectric Properties of Potassium and Rubidium Titanyl-Arsenate Single Crystals in the Temperature Range of 4.2-300 K

Energy Technology Data Exchange (ETDEWEB)

Shaldin, Yu. V., E-mail: yuri1999@rambler.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Matyjasik, S. [International Laboratory of Strong Magnetic Fields and Low Temperatures (Poland); Novikova, N. E. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Tseitlin, M.; Mozhaev, E. [Ariel University Center of Samaria (Israel); Roth, M. [Hebrew University, School of Applied Sciences (Israel)

2010-11-15

The temperature dependences of the pyroelectric coefficients of KTiOAsO{sub 4} and RbTiOAsO{sub 4} single crystals grown by flux crystallization have been investigated in the temperature range of 4.2-300 K. With an increase in temperature, superionic conductivity first arises in KTiOAsO4 (at T > 200 K) and then (at T > 270 K) in RbTiOAsO{sub 4}. This conductivity is much higher in the samples polarized at T = 4.2 K. An exponential change in the crystal resistivity along the polar direction is simultaneously observed. The results of measurements in the range of 4.2-200 K indicate larger values of pyroelectric coefficients when compared with potassium and rubidium titanyl-phosphate crystals. A correlation between the pyroelectric coefficients and a change in the lattice constants at isomorphic substitutions of K atoms for Rb and P atoms for As has been revealed within the symmetry approach.

Highly accurate Michelson type wavelength meter that uses a rubidium stabilized 1560 nm diode laser as a wavelength reference

International Nuclear Information System (INIS)

Masuda, Shin; Kanoh, Eiji; Irisawa, Akiyoshi; Niki, Shoji

2009-01-01

We investigated the accuracy limitation of a wavelength meter installed in a vacuum chamber to enable us to develop a highly accurate meter based on a Michelson interferometer in 1550 nm optical communication bands. We found that an error of parts per million order could not be avoided using famous wavelength compensation equations. Chromatic dispersion of the refractive index in air can almost be disregarded when a 1560 nm wavelength produced by a rubidium (Rb) stabilized distributed feedback (DFB) diode laser is used as a reference wavelength. We describe a novel dual-wavelength self-calibration scheme that maintains high accuracy of the wavelength meter. The method uses the fundamental and second-harmonic wavelengths of an Rb-stabilized DFB diode laser. Consequently, a highly accurate Michelson type wavelength meter with an absolute accuracy of 5x10 -8 (10 MHz, 0.08 pm) over a wide wavelength range including optical communication bands was achieved without the need for a vacuum chamber.

Enthalpies of the dissolution and dilution of aqueous solutions of rubidium and cesium diclofenac at 293.15-318.15 K

Science.gov (United States)

Manin, N. G.; Perlovich, G. L.; Fini, A.

2014-03-01

Enthalpies of the dissolution and dilution of aqueous solutions of rubidium and cesium diclofenac (RbDC and CsDC) are measured at 293.15, 298.15, 308.15, and 318.15 K at concentrations of water of less than 0.1 mol/kg. The heat capacity of RbDC and CsDC crystal salts is determined. Changes in the thermodynamic properties of both a solution and its components vs. concentration and temperature is considered. An increase in the endothermicity of the dissolution of RbDC and CsDC with a rise in temperature is noted. It is shown that the dissolution of both RbDC and CsDC electrolytes in water is determined by the contribution from entropy. It is shown that in aqueous solutions of RbDC and CsDC, the degree of binding of water molecules is higher than in pure water at temperatures below 303.15 K.

Crystal structure of ammonium octacyanomolybdate(IV) and rubidium octacyanomolybdate(IV)

Energy Technology Data Exchange (ETDEWEB)

Semenishin, D.I.; Glovyak, T.; Mys' kiv, M.G.

1985-11-01

The crystal structure of ammonium octacyanomolybdate(IV) and rubidium octacyanomolybdate(IV) has been determined by the single-crystal method on a Syntex P2/sub 1/ automatic diffractometer: ((NH/sub 4/)/sub 4/ Mo(CN)/sub 4/) 0.5H/sub 2/O (I) (space group Pma2, a = 15.550(3), b = 14.118(3), c = 7.438(1) A, Z = 4, R = 0.062) and Rb/sub 4/(Mo(CN)/sub 8/). 3H/sub 2/O (II) (space group P4/sub 1/2/sub 1/2, a = 9.300(10, c = 21.807(3) A, Z = 4, R = 0.065). The Mo atoms in structure I occupy two special positions (2(b) and 2(c)) and are each surrounded by eight CN ligands. The mean value of the Mo-C distances for Mo(1) is equal to 2.216 A, and the corresponding value for Mo(2) is 2.235 A. The mean Mo-N lengths are practically identical in both molybdenum anions and are equal to 3.353 A. The mean values of the C identical with N bond lengths in the Mo(1) and Mo(2) anions are 1.118 and 1.137 A, respectively. The MoCn angles vary from 175.0 to 178.4/sup 0/. The coordination sphere of the Mo(1) atom corresponds to a dodecahedron with a single twofold symmetry axis, and the coordination polyhedron of the Mo(2) atom in an antiprism of m symmetry. In structure II the Mo-C distances are within the 2.130-2.160-A range, and the Mo-N distances range from 3.290 to 3.307 A. The MoCN angles vary from 176.0 to 179.3/sup 0/, and the coordination polyhedron of (MoC/sub 8/) is a dodecahedron of 2 symmetry. The existence of two types of coordination of Mo in structure I is presently the only example among the structurally studied octahyanomolybdates(IV).

Stable isotope studies

International Nuclear Information System (INIS)

Ishida, T.

1992-01-01

The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

Raman scattering method and apparatus for measuring isotope ratios and isotopic abundances

International Nuclear Information System (INIS)

Harney, R.C.; Bloom, S.D.

1978-01-01

Raman scattering is used to measure isotope ratios and/or isotopic abundances. A beam of quasi-monochromatic photons is directed onto the sample to be analyzed, and the resulting Raman-scattered photons are detected and counted for each isotopic species of interest. These photon counts are treated mathematically to yield the desired isotope ratios or isotopic abundances

Isotope separation

International Nuclear Information System (INIS)

Bartlett, R.J.; Morrey, J.R.

1978-01-01

A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated

Isotopic separation

International Nuclear Information System (INIS)

Chen, C.L.

1979-01-01

Isotopic species in an isotopic mixture including a first species having a first isotope and a second species having a second isotope are separated by selectively exciting the first species in preference to the second species and then reacting the selectively excited first species with an additional preselected radiation, an electron or another chemical species so as to form a product having a mass different from the original species and separating the product from the balance of the mixture in a centrifugal separating device such as centrifuge or aerodynamic nozzle. In the centrifuge the isotopic mixture is passed into a rotor where it is irradiated through a window. Heavier and lighter components can be withdrawn. The irradiated mixture experiences a large centrifugal force and is separated in a deflection area into lighter and heavier components. (UK)

Chromium isotope variations

DEFF Research Database (Denmark)

D'Arcy, Joan Mary

the δ53Cr value of continental runoff into the ocean. The major findings were that river water is characterised by heavy δ53Cr values (+0.1‰ to +1.6‰), while soils are characterised by light δ53Cr values (-0.3‰), relative to the catchment bedrock (-0.17‰ to -0.21‰), indicating that Cr isotopes......, and the quantification the Cr isotope composition of major Cr fluxes into and out of ocean. This thesis adds to the current knowledge of the Cr isotope system and is divided into two studies. The focus of the first study was to determine what processes control the Cr isotopic compositionof river water and to quantify......Chromium (Cr) stable isotopes are a useful tracer of changes in redox conditions because changes in its oxidation state are accompanied by an isotopic fractionation. For this reason the Cr isotope system is being developed as a potential tool for paleo-redox reconstruction. Dissolved Cr in seawater...

Environmental isotope hydrology

International Nuclear Information System (INIS)

1973-01-01

Environmental isotope hydrology is a relatively new field of investigation based on isotopic variations observed in natural waters. These isotopic characteristics have been established over a broad space and time scale. They cannot be controlled by man, but can be observed and interpreted to gain valuable regional information on the origin, turnover and transit time of water in the system which often cannot be obtained by other techniques. The cost of such investigations is usually relatively small in comparison with the cost of classical hydrological studies. The main environmental isotopes of hydrological interest are the stable isotopes deuterium (hydrogen-2), carbon-13, oxygen-18, and the radioactive isotopes tritium (hydrogen-3) and carbon-14. Isotopes of hydrogen and oxygen are ideal geochemical tracers of water because their concentrations are usually not subject to change by interaction with the aquifer material. On the other hand, carbon compounds in groundwater may interact with the aquifer material, complicating the interpretation of carbon-14 data. A few other environmental isotopes such as 32 Si and 238 U/ 234 U have been proposed recently for hydrological purposes but their use has been quite limited until now and they will not be discussed here. (author)

On the sources of uranium in some Scottish Caledonian granites

International Nuclear Information System (INIS)

Halliday, A.N.

1982-01-01

The lead isotope systematics, zircon uranium concentrations and whole-rock rubidium concentrations of 11 Scottish Caledonian granites are examined for clues to the origin of their uranium. A positive correlation between U in zircon and initial lead isotope ratios suggests that U and Pb were derived from the same source which, as some of these granites contain their U in inherited zircons, is likely to have been within the crust. It is argued, therefore, that most of the uranium in these granites had a crustal derivation but lead isotope ratios indicate that any Lewisian contribution was minor in comparison with those from postulated Grenville, Morarian or Caledonian metamorphic reservoirs. However, additional data are required before this conclusion can be extended to include uraniferous Caledonian granites such as Cairngorm. (author)

Stable isotopes

International Nuclear Information System (INIS)

Brazier, J.L.; Guinamant, J.L.

1995-01-01

According to the progress which has been realised in the technology of separating and measuring isotopes, the stable isotopes are used as preferable 'labelling elements' for big number of applications. The isotopic composition of natural products shows significant variations as a result of different reasons like the climate, the seasons, or their geographic origins. So, it was proved that the same product has a different isotopic composition of alimentary and agriculture products. It is also important in detecting the pharmacological and medical chemicals. This review article deals with the technology, like chromatography and spectrophotometry, adapted to this aim, and some important applications. 17 refs. 6 figs

Optical isotope shifts for unstable samarium isotopes

International Nuclear Information System (INIS)

Eastham, D.A.; Walker, P.M.; Griffith, J.A.R.; Evans, D.E.; Grant, I.S.; England, J.G.; Fawcett, M.J.

1984-01-01

Using a tunable dye laser beam intersecting a thermal atomic beam, optical isotope shifts and hyperfine splittings have been measured for the four unstable samarium isotopes between 144 Sm and 154 Sm, covering the well known transition region from spherical to deformed shapes. (orig.)

Electron linac for medical isotope production with improved energy efficiency and isotope recovery

Science.gov (United States)

Noonan, John; Walters, Dean; Virgo, Matt; Lewellen, John

2015-09-08

A method and isotope linac system are provided for producing radio-isotopes and for recovering isotopes. The isotope linac is an energy recovery linac (ERL) with an electron beam being transmitted through an isotope-producing target. The electron beam energy is recollected and re-injected into an accelerating structure. The ERL provides improved efficiency with reduced power requirements and provides improved thermal management of an isotope target and an electron-to-x-ray converter.

Experimental study on isotope fractionation of evaporating water of different initial isotopic composition

International Nuclear Information System (INIS)

Pooja Devi; Jain, A.K.; Rao, M.S.; Kumar, B.

2014-01-01

The studies of evaporative isotopic fractionation in controlled conditions are of particular importance for understanding the mechanism of evaporation fractionation in natural conditions. We present the measurements of the average isotopic fractionation factors during the evaporation of water having different initial isotopic compositions at constant temperature. The results show that the isotopic composition of residual water become more enriched over the time and the initial isotopic composition of evaporating water has considerable effect on the average isotopic fractionation factors. The average isotopic fractionation factors in evaporation of Water A and Water B under the present experimental conditions were found to be 0.9817 ± 0.0044 and 0.9887 ± 0.0031 for oxygen and 0.9178 ± 0.0182 and 0.9437 ± 0.0169 for hydrogen, respectively. The findings of this work should lead to a better understanding and use of stable isotope techniques in isotope hydrology by using a simple technique of evaporation pan. (author)

Isotope puzzle in sputtering

International Nuclear Information System (INIS)

Zheng Liping

1998-01-01

Mechanisms affecting multicomponent material sputtering are complex. Isotope sputtering is the simplest in the multicomponent materials sputtering. Although only mass effect plays a dominant role in the isotope sputtering, there is still an isotope puzzle in sputtering by ion bombardment. The major arguments are as follows: (1) At the zero fluence, is the isotope enrichment ejection-angle-independent or ejection-angle-dependent? (2) Is the isotope angular effect the primary or the secondary sputter effect? (3) How to understand the action of momentum asymmetry in collision cascade on the isotope sputtering?

Isotopically controlled semiconductors

Energy Technology Data Exchange (ETDEWEB)

Haller, Eugene E.

2006-06-19

The following article is an edited transcript based on the Turnbull Lecture given by Eugene E. Haller at the 2005 Materials Research Society Fall Meeting in Boston on November 29, 2005. The David Turnbull Lectureship is awarded to recognize the career of a scientist who has made outstanding contributions to understanding materials phenomena and properties through research, writing, and lecturing, as exemplified by the life work of David Turnbull. Haller was named the 2005 David Turnbull Lecturer for his 'pioneering achievements and leadership in establishing the field of isotopically engineered semiconductors; for outstanding contributions to materials growth, doping and diffusion; and for excellence in lecturing, writing, and fostering international collaborations'. The scientific interest, increased availability, and technological promise of highly enriched isotopes have led to a sharp rise in the number of experimental and theoretical studies with isotopically controlled semiconductor crystals. This article reviews results obtained with isotopically controlled semiconductor bulk and thin-film heterostructures. Isotopic composition affects several properties such as phonon energies, band structure, and lattice constant in subtle, but, for their physical understanding, significant ways. Large isotope-related effects are observed for thermal conductivity in local vibrational modes of impurities and after neutron transmutation doping. Spectacularly sharp photoluminescence lines have been observed in ultrapure, isotopically enriched silicon crystals. Isotope multilayer structures are especially well suited for simultaneous self- and dopant-diffusion studies. The absence of any chemical, mechanical, or electrical driving forces makes possible the study of an ideal random-walk problem. Isotopically controlled semiconductors may find applications in quantum computing, nanoscience, and spintronics.

Pb-Sr-Nd-O isotopic characterization of Mesozoic rocks throughout the northern end of the Peninsular Ranges batholith: Isotopic evidence for the magmatic evolution of oceanic arc–continental margin accretion during the Late Cretaceous of southern California

Science.gov (United States)

Kistler, Ronald W.; Wooden, Joseph L.; Premo, Wayne R.; Morton, Douglas M.

2014-01-01

Within the duration of the U.S. Geological Survey (USGS)–based Southern California Areal Mapping Project (SCAMP), many samples from the northern Peninsular Ranges batholith were studied for their whole-rock radioisotopic systematics (rubidium-strontium [Rb-Sr], uranium-thorium-lead [U-Th-Pb], and samarium-neodymium [Sm-Nd]), as well as oxygen (O), a stable isotope. The results of three main studies are presented separately, but here we combine them (>400 analyses) to produce a very complete Pb-Sr-Nd-O isotopic profile of an arc-continent collisional zone—perhaps the most complete in the world. In addition, because many of these samples have U-Pb zircon as well as argon mineral age determinations, we have good control of the timing for Pb-Sr-Nd-O isotopic variations.The ages and isotopic variations help to delineate at least four zones across the batholith from west to east—an older western zone (126–108 Ma), a transitional zone (111–93 Ma), an eastern zone (94–91 Ma), and a much younger allochthonous thrust sheet (ca. 84 Ma), which is the upper plate of the Eastern Peninsular Ranges mylonite zone. Average initial 87Sr/86 Sr (Sri), initial 206Pb/204Pb (206 Pbi), initial 208Pb/204Pb (average 208Pbi), initial epsilon Nd (average εNdi), and δ18O signatures range from 0.704, 18.787, 38.445, +3.1, and 4.0‰–9.0‰, respectively, in the westernmost zone, to 0.7071, 19.199, 38.777, −5, and 9‰–12‰, respectively, in the easternmost zone. The older western zone is therefore the more chemically and isotopically juvenile, characterized mostly by values that are slightly displaced from a mantle array at ca. 115 Ma, and similar to some modern island-arc signatures. In contrast, the isotopic signatures in the eastern zones indicate significant amounts of crustal involvement in the magmatic plumbing of those plutons. These isotopic signatures confirm previously published results that interpreted the Peninsular Ranges batholith as a progressively

Method for separating isotopes

International Nuclear Information System (INIS)

Schlenker, R.F.

1978-01-01

A vortex tube for separating isotopes is described. A gas mixture containing the isotopic molecules enters the vortex tube under pressure and is separated into a hot discharge flow stream and a cold discharge flow stream. The hot discharge is enriched in lighter isotopic molecules whereas the cold discharge flow stream is enriched in the heavier isotopic molecules. The vortex tube can be used in a single stage or multistage isotope separation apparatus

Method for separating isotopes

International Nuclear Information System (INIS)

Jepson, B.E.

1975-01-01

Isotopes are separated by contacting a feed solution containing the isotopes with a cyclic polyether wherein a complex of one isotope is formed with the cyclic polyether, the cyclic polyether complex is extracted from the feed solution, and the isotope is thereafter separated from the cyclic polyether

Solution enthalpies of alkali metal halides in water and heavy water mixtures with dimethyl sulfoxide

International Nuclear Information System (INIS)

Egorov, G.I.

1994-01-01

Solution enthalpies of CsF, LiCl, NaI, CsI and some other halides of alkali metals and tetrabutylammonium have been measured by the method of calorimetry. Standard solution enthalpies of all alkali metals (except rubidium) halides in water and heavy water mixtures with dimethylsulfoxide at 298.15 K have been calculated. Isotopic effects in solvation enthalpy of the electrolytes mentioned in aqueous solutions of dimethylsulfoxide have been discussed. 29 refs., 2 figs., 4 tabs

Calculation of isotope selective excitation of uranium isotopes using spectral simulation method

International Nuclear Information System (INIS)

Al-Hassanieh, O.

2009-06-01

Isotope ratio enhancement factor and isotope selectivity of 235 U in five excitation schemes (I: 0→10069 cm - 1 →IP, II: 0 →10081 cm - 1 →IP, III: 0 →25349 cm - 1→ IP, IV: 0→28650 cm - 1 →IP, V: 0→16900 cm - 1 →34659 cm - 1 →IP), were computed by a spectral simulation approach. The effect of laser bandwidth and Doppler width on the isotope ratio enhancement factor and isotope selectivity of 235 U has been studied. The photoionization scheme V gives the highest isotope ratio enhancement factor. The main factors which effect the separation possibility are the isotope shift and the relative intensity of the transitions between hyperfine levels. The isotope ratio enhancement factor decreases exponentially by increasing the Doppler width and the laser bandwidth, where the effect of Doppler width is much greater than the effect of the laser bandwidth. (author)

Isotopic clusters

International Nuclear Information System (INIS)

Geraedts, J.M.P.

1983-01-01

Spectra of isotopically mixed clusters (dimers of SF 6 ) are calculated as well as transition frequencies. The result leads to speculations about the suitability of the laser-cluster fragmentation process for isotope separation. (Auth.)

Method for separating isotopes

International Nuclear Information System (INIS)

Jepson, B.E.

1976-01-01

The invention comprises a method for separating different isotopes of elements from each other by contacting a feed solution containing the different isotopes with a macrocyclic polyether to preferentially form a macrocyclic polyether complex with the lighter of the different isotopes. The macrocyclic polyether complex is then separated from the lighter isotope depleted feed solution. A chemical separation of isotopes is carried out in which a constant refluxing system permits a continuous countercurrent liquid-liquid extraction. (LL)

Exploring the isotopic niche: isotopic variance, physiological incorporation, and the temporal dynamics of foraging

Directory of Open Access Journals (Sweden)

Justin Douglas Yeakel

2016-01-01

Full Text Available Consumer foraging behaviors are dynamic, changing in response to prey availability, seasonality, competition, and even the consumer's physiological state. The isotopic composition of a consumer is a product of these factors as well as the isotopic `landscape' of its prey, i.e. the isotopic mixing space. Stable isotope mixing models are used to back-calculate the most likely proportional contribution of a set of prey to a consumer's diet based on their respective isotopic distributions, however they are disconnected from ecological process. Here we build a mechanistic framework that links the ecological and physiological processes of an individual consumer to the isotopic distribution that describes its diet, and ultimately to the isotopic composition of its own tissues, defined as its `isotopic niche’. By coupling these processes, we systematically investigate under what conditions the isotopic niche of a consumer changes as a function of both the geometric properties of its mixing space and foraging strategies that may be static or dynamic over time. Results of our derivations reveal general insight into the conditions impacting isotopic niche width as a function of consumer specialization on prey, as well as the consumer's ability to transition between diets over time. We show analytically that moderate specialization on isotopically unique prey can serve to maximize a consumer's isotopic niche width, while temporally dynamic diets will tend to result in peak isotopic variance during dietary transitions. We demonstrate the relevance of our theoretical findings by examining a marine system composed of nine invertebrate species commonly consumed by sea otters. In general, our analytical framework highlights the complex interplay of mixing space geometry and consumer dietary behavior in driving expansion and contraction of the isotopic niche. Because this approach is established on ecological mechanism, it is well-suited for enhancing the

Production and spectroscopy of ultracold YbRb* molecules

International Nuclear Information System (INIS)

Nemitz, Nils

2008-11-01

This thesis describes the formation of electronically excited but translationally cold molecules formed from rubidium atoms and two isotopes of ytterbium ( 176 Yb and 174 Yb) by means of photoassociation. The experiments were performed in a combined MOT with 10 9 rubidium atoms and 2.10 6 ytterbium atoms at temperatures of less than 1 mK. Photoassociation lines were found by trap loss spectroscopy throughout a wavelength range of 2 nm near the 795 nm D1 transition in rubidium. The majority of lines belong to two vibrational series in the excited YbRb * molecule, converging on a system of a ground state ytterbium atom and an excited rubidium atom. The strong variation of line strength between different vibrational lines is explained through the Franck-Condon principle. An improved version of the Leroy-Bernstein equation was used to extract the leading dispersion coefficient of the potential from the vibrational progression. Most of the observed lines show a resolved rotational structure as expected from a basic quantum mechanical model. The series terminates with the third or forth rotational component due to the ground state centrifugal barrier.The measured rotational constants agree very well with calculations based on the C 6 coefficient. The discovery of a splitting of the rotational components into subcomponents indicates an uncommon angular momentum coupling described by Hund's case. Variations in the depth of the subcomponents indicates a similar splitting in the ground state, with the energies of the substates based on the alignment of the rubidium atom's magnetic dipole moment relative to the angular momentum carried by an approaching ytterbium atom. This creates an additional ground state barrier, partially suppressing some of the subcomponents. Using a rate equation model developed for this purpose, a maximum formation rate of 2.5.10 6 molecules per second was calculated over the volume of the entire trap. The work presented here is an important step on

Isotope effects on nuclear shielding

International Nuclear Information System (INIS)

Hansen, P.E.

1983-01-01

This review concentrates upon empirical trends and practical uses of mostly secondary isotope effects, both of the intrinsic and equilibrium types. The text and the tables are arranged in the following fashion. The most 'popular' isotope effect is treated first, deuterium isotope effects on 13 C nuclear shielding, followed by deuterium on 1 H nuclear shieldings, etc. Focus is thus on the isotopes producing the effect rather than on the nuclei suffering the effect. After a brief treatment of each type of isotope effect, general trends are dealt with. Basic trends of intrinsic isotope effects such as additivity, solvent effects, temperature effects, steric effects, substituent effects and hyperconjugation are discussed. Uses of isotope effects for assignment purposes, in stereochemical studies, in hydrogen bonding and in isotopic tracer studies are dealt with. Kinetic studies, especially of phosphates, are frequently performed by utilizing isotope effects. In addition, equilibrium isotope effects are treated in great detail as these are felt to be new and very important and may lead to new uses of isotope effects. Techniques used to obtain isotope effects are briefly surveyed at the end of the chapter. (author)

Laser assisted aerodynamic isotope separation

International Nuclear Information System (INIS)

Berg, H. van den

1985-01-01

It is shown that the efficiency of conventional aerodynamic isotope seperation can be improved by two orders of magnitude with the aid of a relatively weak cw infrared laser which is used to induce isotopically selective condensation. Overall isotope enrichment factors in excess of 2 are obtained as compared to about 1.02 in the conventional seperation. Sulphur isotopes in SF 6 as well as Silicon isotopes in SiF 4 and Bromine isotopes in CF 3 Br are seperated on a laboratory scale. Infrared vibrational predissociation by itself and in combination with isotopically selective condensation are also shown to be effective new ways of isotope separation. (orig.) [de

Separation of uranium isotopes by accelerated isotope exchange reactions

International Nuclear Information System (INIS)

Seko, M.; Miyake, T.; Inada, K.; Ochi, K.; Sakamoto, T.

1977-01-01

A novel catalyst for isotope exchange reaction between uranium(IV) and uranium(VI) compounds enables acceleration of the reaction rate as much as 3000 times to make industrial separation of uranium isotopes economically possible

Applications of isotopes

International Nuclear Information System (INIS)

Kirby-Smith, J.S.

1976-01-01

Current and potential applications of stable isotopes as tracers in a number of biomedical and environmental areas are discussed. It is pointed out that a wide variety of problems exist in these fields whose solutions in principle are amenable to the isotopic approach. The number and diversity of these problems as well as the unique role stable isotopes can play in their solution illustrate the importance of achieving and maintaining a broad inventory of isotopic species. Experience has demonstrated unequivocally an additional overriding requirement for widespread exploration of stable isotopes by the scientific and technical community, i.e., the need for low cost availability of the materials in quantity. Some representative applications of 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, and 18 O are discussed

Economic analysis of clinical positron emission tomography of the heart with rubidium-82

International Nuclear Information System (INIS)

Gould, K.L.; Goldstein, R.A.; Mullani, N.A.

1989-01-01

This report describes a cost analysis for clinical positron emission tomography (PET) of the heart using generator produced rubidium-82 ( 82 Rb). Considered sequentially are the clinical problem, current noninvasive radionuclide methods, positron emission tomograph, and the cost of PET per study. Also analyzed are the costs of PET versus thallium imaging in the management of chest pain, for screening asymptomatic men at high risk for coronary artery disease and for evaluating myocardial viability after myocardial infarction or thrombolytic therapy. Noninvasive assessment of coronary artery stenosis and myocardial ischemia/viability in symptomatic or asymptomatic subjects remains a major medical problem because the sensitivity and specificity of thallium imaging are only 70-85% and 50-70%, respectively, in recent studies. Cardiac positron imaging has an accuracy for noninvasive diagnosis of coronary artery disease in symptomatic or asymptomatic patients with a sensitivity and specificity of 95-98%. It can also be used for assessing physiologic stenosis severity, for imaging myocardial infarction and viability, for assessing effects of interventions such as thrombolysis, percutaneous transluminal coronary angioplasty (PTCA) or bypass surgery on myocardial perfusion, metabolism or coronary flow reserve, for assessing collateral function noninvasively in man, and for diagnosing cardiomyopathy not due to coronary artery disease. Although the cost for cardiac PET with 82 Rb may be modestly higher than for 201 Tl, the greater diagnostic yield of PET results in comparable or lower overall medical management costs than no diagnostic tests/interventions and lower overall costs compared to thallium imaging for evaluating patients with chest pain, asymptomatic high risk males, and patients after acute myocardial infarction/thrombolysis for myocardial viability

Isotopes in heterogeneous catalysis

CERN Document Server

Hargreaves, Justin SJ

2006-01-01

The purpose of this book is to review the current, state-of-the-art application of isotopic methods to the field of heterogeneous catalysis. Isotopic studies are arguably the ultimate technique in in situ methods for heterogeneous catalysis. In this review volume, chapters have been contributed by experts in the field and the coverage includes both the application of specific isotopes - Deuterium, Tritium, Carbon-14, Sulfur-35 and Oxygen-18 - as well as isotopic techniques - determination of surface mobility, steady state transient isotope kinetic analysis, and positron emission profiling.

Geochemistry of silicon isotopes

Energy Technology Data Exchange (ETDEWEB)

Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

2018-04-01

Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

ICT: isotope correction toolbox.

Science.gov (United States)

Jungreuthmayer, Christian; Neubauer, Stefan; Mairinger, Teresa; Zanghellini, Jürgen; Hann, Stephan

2016-01-01

Isotope tracer experiments are an invaluable technique to analyze and study the metabolism of biological systems. However, isotope labeling experiments are often affected by naturally abundant isotopes especially in cases where mass spectrometric methods make use of derivatization. The correction of these additive interferences--in particular for complex isotopic systems--is numerically challenging and still an emerging field of research. When positional information is generated via collision-induced dissociation, even more complex calculations for isotopic interference correction are necessary. So far, no freely available tools can handle tandem mass spectrometry data. We present isotope correction toolbox, a program that corrects tandem mass isotopomer data from tandem mass spectrometry experiments. Isotope correction toolbox is written in the multi-platform programming language Perl and, therefore, can be used on all commonly available computer platforms. Source code and documentation can be freely obtained under the Artistic License or the GNU General Public License from: https://github.com/jungreuc/isotope_correction_toolbox/ {christian.jungreuthmayer@boku.ac.at,juergen.zanghellini@boku.ac.at} Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Uses of stable isotopes

International Nuclear Information System (INIS)

Axente, Damian

1998-01-01

The most important fields of stable isotope use with examples are presented. These are: 1. Isotope dilution analysis: trace analysis, measurements of volumes and masses; 2. Stable isotopes as tracers: transport phenomena, environmental studies, agricultural research, authentication of products and objects, archaeometry, studies of reaction mechanisms, structure and function determination of complex biological entities, studies of metabolism, breath test for diagnostic; 3. Isotope equilibrium effects: measurement of equilibrium effects, investigation of equilibrium conditions, mechanism of drug action, study of natural processes, water cycle, temperature measurements; 4. Stable isotope for advanced nuclear reactors: uranium nitride with 15 N as nuclear fuel, 157 Gd for reactor control. In spite of some difficulties of stable isotope use, particularly related to the analytical techniques, which are slow and expensive, the number of papers reporting on this subject is steadily growing as well as the number of scientific meetings organized by International Isotope Section and IAEA, Gordon Conferences, and regional meeting in Germany, France, etc. Stable isotope application development on large scale is determined by improving their production technologies as well as those of labeled compound and the analytical techniques. (author)

Intracellular Cadmium Isotope Fractionation

Science.gov (United States)

Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

2011-12-01

Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

Applications of stable isotopes

International Nuclear Information System (INIS)

Letolle, R.; Mariotti, A.; Bariac, T.

1991-06-01

This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

High mass isotope separation arrangement

International Nuclear Information System (INIS)

Eerkens, J.W.

1976-01-01

An isotope separation arrangement for separating a preselected isotope from a mixture of chemically-identical but isotopically-different molecules by either photon-induced pure revibrational or vibronic selective excitation of the molecules containing the atoms of the isotope to be separated from a lower to a higher energy state, and a chemical reaction of the higher energy state molecules with a chemically-reactive agent to form a chemical compound containing primarily the atoms of the isotope to be separated in a physicochemical state different from the physicochemical state of the mixture of chemically-identical but isotopically-different molecules. The chemical compound containing the atoms of the isotope to be separated may be subsequently processed to obtain the isotope. The laser configuration used to generate the photon beam is fully described

Isotope separation process

International Nuclear Information System (INIS)

Lyon, R.K.

1976-01-01

The instant invention relates to a process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in said material. In one embodiment, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by selective dissociation of said excited molecules by the absorption of a single photon of visible or ultraviolet light. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium. 11 Claims, 2 Drawing Figures

Isotope laboratories

International Nuclear Information System (INIS)

1978-01-01

This report from the Dutch Ministry of Health is an advisory document concerned with isotope laboratories in hospitals, in connection with the Dutch laws for hospitals. It discusses which hospitals should have isotope laboratories and concludes that as many hospitals as possible should have small laboratories so that emergency cases can be dealt with. It divides the Netherlands into regions and suggests which hospitals should have these facilities. The questions of how big each lab. is to be, what equipment each has, how each lab. is organised, what therapeutic and diagnostic work should be carried out by each, etc. are discussed. The answers are provided by reports from working groups for in vivo diagnostics, in vitro diagnostics, therapy, and safety and their results form the criteria for the licences of isotope labs. The results of a questionnaire for isotope labs. already in the Netherlands are presented, and their activities outlined. (C.F.)

ISOTOPE METHODS IN HOMOGENEOUS CATALYSIS.

Energy Technology Data Exchange (ETDEWEB)

BULLOCK,R.M.; BENDER,B.R.

2000-12-01

The use of isotope labels has had a fundamentally important role in the determination of mechanisms of homogeneously catalyzed reactions. Mechanistic data is valuable since it can assist in the design and rational improvement of homogeneous catalysts. There are several ways to use isotopes in mechanistic chemistry. Isotopes can be introduced into controlled experiments and followed where they go or don't go; in this way, Libby, Calvin, Taube and others used isotopes to elucidate mechanistic pathways for very different, yet important chemistries. Another important isotope method is the study of kinetic isotope effects (KIEs) and equilibrium isotope effect (EIEs). Here the mere observation of where a label winds up is no longer enough - what matters is how much slower (or faster) a labeled molecule reacts than the unlabeled material. The most careti studies essentially involve the measurement of isotope fractionation between a reference ground state and the transition state. Thus kinetic isotope effects provide unique data unavailable from other methods, since information about the transition state of a reaction is obtained. Because getting an experimental glimpse of transition states is really tantamount to understanding catalysis, kinetic isotope effects are very powerful.

Process for isotope separation

International Nuclear Information System (INIS)

Emile, B.F.M.

1983-11-01

A process is claimed for isotopic separation applied to isotopes of elements that can be placed in at least a physicochemical form in which the isotopic atoms or the molecules containing these atoms can be easily displaced and for which there are selective radiations preferentially absorbed by the isotopes of a certain type or by the molecules containing them, said absorption substantially increasing the probability of ionization of said atoms or molecules relative to the atoms or molecules that did not absorb the radiation. The process consists of placing the isotopic mixture in such a form, subjecting it in a separation zone to selective radiations and to an electrical field that produces migration of positive ions toward the negative electrodes and negative ions toward the positive electrodes, and withdrawing from certain such zones the fractions thus enriched in certain isotopes

Isotope separation process

International Nuclear Information System (INIS)

Cabicar, J.; Stamberg, K.; Katzer, J.

1983-01-01

A process for separating isotopes by the method of controlled distribution is claimed. A first phase is either a solution of isotopic components and a ligand (from 10 - 6 M to a saturated solution), or a gaseous mixture of isotopic components, or a gaseous mixture of isotopic components and an inert gas. The isotopes are in the starting mixture in molar ratio from 1:10 5 to 1:10 - 5 . The second phase is a solid sorbent such as styrene-divinylbenzene ion exchangers, or bio-sorbents on the basis of mycelium of lower fungi and sorbents on the basis of cellulose, or an extraction agent such as tributyl phosphate and trioctyl amine, if need be, kept by a carrier such as teflon, silica gel and cellulose. The two-phase system exhibits non-linear equilibrium isotherm for sorption and/or desorption or for extraction and/or re-extraction. After bringing both phases into contact the rate of transport of isotopic components from one phase into another is not equal. Retardation of isotopic exchange takes place by complexation of isotopes with ligands such as cabonate, sulphate, citrate, chloride and ethylenediamine tetraacetate ions, or by using sorbents and extraction agents with chelating functional groups such as carboxyl and hyroxyl groups, groups on the basis of phosphorus, nitrogen and sulphur and/or by operating in darkness, or in the light having wave length between 2.5x10 2 and 10 9 nm. The contact time is between 10 - 2 and 10 6 s, temperature between 10 2 and 10 3 K, the number of stirrer revolutions between 10 - 2 and 10 4 revolutions per s, flow rate at column arrangement between 10 - 6 and 10 - 1 m/s and the size of particles of sorbent between 10 - 6 and 10 - 2 m

Isotope separation process

International Nuclear Information System (INIS)

Thomas, W.R.L.

1979-01-01

The instant invention relates to an improved process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same element in said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by a step wherein more of the excited molecules than non-excited molecules are converted to a chemically different form which may be separated by means known in the art. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium

Isotope separation process

International Nuclear Information System (INIS)

Lyon, R.K.

1977-01-01

The instant invention relates to a process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by a step wherein more of the excited molecules than nonexcited molecules are converted to a chemically different form which may be separated by means known in the art. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium. 15 claims, 1 figure

Isotope separation method and apparatus

International Nuclear Information System (INIS)

Lyon, R.K.; Eisner, P.N.; Thomas, W.R.L.

1980-01-01

A method and apparatus are specified for separating a mixture of isotopes present in a compound, preferably a gaseous compound, into two or more parts in each of which the abundances of the isotopes differ from the natural abundances of the isotopes in the compound. The invention particularly relates to carrying out a laser induced, isotopically selective conversion of gaseous molecules in such a manner as to achieve more than one stage of isotope separation along the length of the laser beam. As an example, the invention is applied to the separation of the isotopes of uranium in UF 6 , in which either the U-235 or U-238 isotope is selectively excited by means of irradiation from an infrared laser, and the selectively excited isotope converted into a product that can be recovered from UF 6 by one of a variety of methods that are described. (U.K.)

Isotope angiocardiography

International Nuclear Information System (INIS)

Stepinska, J.; Ruzyllo, W.; Konieczny, W.

1979-01-01

Method of technetium isotope 99 m pass through the heart recording with the aid of radioisotope scanner connected with seriograph and computer is being presented. Preliminary tests were carried out in 26 patients with coronary disease without or with previous myocardial infarction, cardiomyopathy, ventricular septal defect and in patients with artificial mitral and aortic valves. The obtained scans were evaluated qualitatively and compared with performed later contrast X-rays of the heart. Size of the right ventricle, volume and rate of left atrial evacuation, size and contractability of left ventricle were evaluated. Similarity of direct and isotope angiocardiographs, non-invasional character and repeatability of isotope angiocardiography advocate its usefulness. (author)

International Isotopes Markets

Directory of Open Access Journals (Sweden)

Stanislaw Z. Zhiznin

2016-01-01

Full Text Available The paper studies world markets of stable and radioactive isotopes. Isotopes have found various applications in science, industry, agriculture and other sectors of the economy, but especially - in medicine. Nuclear medicine is developing intensively all over the world thanks to the success in the treatment of various diseases with the help of radioactive pharmaceuticals (radiopharmaceuticals. The article uses empirical data from a forecast study of the global radiopharmaceuticals market made in 2015 by a research company «Markets and Markets» for the European, North American and global markets. The paper also analyzes the statistical data on the global export and import of natural uranium, enriched and depleted uranium, plutonium, thorium and some stable isotopes of non-medical purposes, presented by a company «Trend economy» in 2014. Despite a unique industrial base for the production of isotopes created in the Soviet Union Russia occupies a modest position on the world market of nuclear medicine except for certain areas. More than 80% of isotopes, produced in USSR were consumed domestically, the export of the stable and radioactive isotopes was in equal proportions. Now the country's domestic radiopharmaceuticals market is poorly developed. To radically change the situation, it is necessary to carry out reforms that stimulate the development of nuclear medicine.

Atomic and molecular isotope separation

International Nuclear Information System (INIS)

Melamed, N.T.

1979-01-01

A method for differentially exciting a selected isotopic species in a mixture of isotopic species is described characterized in that almost the entire isotopic mixture is placed in an excited gaseous state; and a preselected isotopic species is then selectively de-excited through stimulated emission

Electrochemically controlled iron isotope fractionation

Science.gov (United States)

Black, Jay R.; Young, Edward D.; Kavner, Abby

2010-02-01

Variations in the stable isotope abundances of transition metals have been observed in the geologic record and trying to understand and reconstruct the physical/environmental conditions that produced these signatures is an area of active research. It is clear that changes in oxidation state lead to large fractionations of the stable isotopes of many transition metals such as iron, suggesting that transition metal stable isotope signatures could be used as a paleo-redox proxy. However, the factors contributing to these observed stable isotope variations are poorly understood. Here we investigate how the kinetics of iron redox electrochemistry generates isotope fractionation. Through a combination of electrodeposition experiments and modeling of electrochemical processes including mass-transport, we show that electron transfer reactions are the cause of a large isotope separation, while mass transport-limited supply of reactant to the electrode attenuates the observed isotopic fractionation. Furthermore, the stable isotope composition of electroplated transition metals can be tuned in the laboratory by controlling parameters such as solution chemistry, reaction overpotential, and solution convection. These methods are potentially useful for generating isotopically-marked metal surfaces for tracking and forensic purposes. In addition, our studies will help interpret stable isotope data in terms of identifying underlying electron transfer processes in laboratory and natural samples.

Three New Offset {delta}{sup 11}B Isotope Reference Materials for Environmental Boron Isotope Studies

Energy Technology Data Exchange (ETDEWEB)

Rosner, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany); IsoAnalysis UG, Berlin (Germany); Vogl, J. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany)

2013-07-15

The isotopic composition of boron is a well established tool in various areas of science and industry. Boron isotope compositions are typically reported as {delta}{sup 11}B values which indicate the isotopic difference of a sample relative to the isotope reference material NIST SRM 951. A significant drawback of all of the available boron isotope reference materials is that none of them covers a natural boron isotope composition apart from NIST SRM 951. To fill this gap of required {delta}{sup 11}B reference materials three new solution boric acid reference materials were produced, which cover 60 per mille of the natural boron isotope variation (-20 to 40 per mille {delta}{sup 11}B) of about 100 per mille . The new reference materials are certified for their {delta}{sup 11}B values and are commercially available through European Reference Materials (http://www.erm-crm.org). The newly produced and certified boron isotope reference materials will allow straightforward method validation and quality control of boron isotope data. (author)

An isotope-enrichment unit and a process for isotope separation

International Nuclear Information System (INIS)

1981-01-01

A process and equipment for isotope enrichment using gas-centrifuge cascades are described. The method is described as applied to the separation of uranium isotopes, using natural-abundance uranium hexafluoride as the gaseous-mixture feedstock. (U.K.)

Carbon isotope ratios and isotopic correlations between components in fruit juices

Science.gov (United States)

Wierzchnicki, Ryszard

2013-04-01

Nowadays food products are defined by geographical origin, method of production and by some regulations concerning terms of their authenticity. Important data for confirm the authenticity of product are providing by isotopic methods of food control. The method checks crucial criteria which characterize the authenticity of inspected product. The European Union Regulations clearly show the tendency for application of the isotopic methods for food authenticity control (wine, honey, juice). The aim of the legislation steps is the protection of European market from possibility of the commercial frauds. Method of isotope ratio mass spectrometry is very effective tool for the use distinguishably the food products of various geographical origin. The basic problem for identification of the sample origin is the lack of databases of isotopic composition of components and information about the correlations of the data. The subject of the work was study the isotopic correlations existing between components of fruits. The chemical and instrumental methods of separation: water, sugars, organic acids and pulp from fruit were implemented. IRMS technique was used to measure isotopic composition of samples. The final results for original samples of fruits (apple, strawberry etc.) will be presented and discussed. Acknowledgement: This work was supported by the Polish Ministry of Science and Higher Education under grant NR12-0043-10/2010.

Measurement of isotope abundance variations in nature by gravimetric spiking isotope dilution analysis (GS-IDA).

Science.gov (United States)

Chew, Gina; Walczyk, Thomas

2013-04-02

Subtle variations in the isotopic composition of elements carry unique information about physical and chemical processes in nature and are now exploited widely in diverse areas of research. Reliable measurement of natural isotope abundance variations is among the biggest challenges in inorganic mass spectrometry as they are highly sensitive to methodological bias. For decades, double spiking of the sample with a mix of two stable isotopes has been considered the reference technique for measuring such variations both by multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) and multicollector-thermal ionization mass spectrometry (MC-TIMS). However, this technique can only be applied to elements having at least four stable isotopes. Here we present a novel approach that requires measurement of three isotope signals only and which is more robust than the conventional double spiking technique. This became possible by gravimetric mixing of the sample with an isotopic spike in different proportions and by applying principles of isotope dilution for data analysis (GS-IDA). The potential and principle use of the technique is demonstrated for Mg in human urine using MC-TIMS for isotopic analysis. Mg is an element inaccessible to double spiking methods as it consists of three stable isotopes only and shows great potential for metabolically induced isotope effects waiting to be explored.

Laser separation of uranium isotopes

International Nuclear Information System (INIS)

Porter, J.T.

1981-01-01

Method and apparatus for separating uranium isotopes are claimed. The method comprises the steps of irradiating a uranyl source material at a wavelength selective to a desired isotope and at an effective temperature for isotope spectral line splitting below about 77 deg.K., further irradiating the source material within the fluorescent lifetime of the source material to selectively photochemically reduce the excited isotopic species, and chemically separating the reduced isotope species from the remaining uranyl salt compound

High mass isotope separation arrangement

International Nuclear Information System (INIS)

Eerkens, J.W.

1980-01-01

This invention relates to the isotope separation art and, more particularly, to a selectively photon-induced energy level transition of an isotopic molecule containing the isotope to be separated and a chemical reaction with a chemically reactive agent to provide a chemical compound containing atoms of the isotope desired. In particular a description is given of a method of laser isotope separation applied to the separation of 235 UF 6 from 238 UF 6 . (U.K.)

Stable oxygen and hydrogen isotopes of brines - comparing isotope ratio mass spectrometry and isotope ratio infrared spectroscopy

Science.gov (United States)

Ahrens, Christian; Koeniger, Paul; van Geldern, Robert; Stadler, Susanne

2013-04-01

Today's standard analytical methods for high precision stable isotope analysis of fluids are gas-water equilibration and high temperature pyrolysis coupled to isotope ratio mass spectrometers (IRMS). In recent years, relatively new laser-based analytical instruments entered the market that are said to allow high isotope precision data on nearly every media. This optical technique is referred to as isotope ratio infrared spectroscopy (IRIS). The objective of this study is to evaluate the capability of this new instrument type for highly saline solutions and a comparison of the analytical results with traditional IRMS analysis. It has been shown for the equilibration method that the presence of salts influences the measured isotope values depending on the salt concentration (see Lécuyer et al, 2009; Martineau, 2012). This so-called 'isotope salt effect' depends on the salt type and salt concentration. These factors change the activity in the fluid and therefore shift the isotope ratios measured by the equilibration method. Consequently, correction factors have to be applied to these analytical data. Direct conversion techniques like pyrolysis or the new laser instruments allow the measurement of the water molecule from the sample directly and should therefore not suffer from the salt effect, i.e. no corrections of raw values are necessary. However, due to high salt concentrations this might cause technical problems with the analytical hardware and may require labor-intensive sample preparation (e.g. vacuum distillation). This study evaluates the salt isotope effect for the IRMS equilibration technique (Thermo Gasbench II coupled to Delta Plus XP) and the laser-based IRIS instruments with liquid injection (Picarro L2120-i). Synthetic salt solutions (NaCl, KCl, CaCl2, MgCl2, MgSO4, CaSO4) and natural brines collected from the Stassfurt Salt Anticline (Germany; Stadler et al., 2012) were analysed with both techniques. Salt concentrations ranged from seawater salinity

Isotope production

Energy Technology Data Exchange (ETDEWEB)

Lewis, Dewi M.

1995-07-15

Some 2 0% of patients using radiopharmaceuticals receive injections of materials produced by cyclotrons. There are over 200 cyclotrons worldwide; around 35 are operated by commercial companies solely for the production of radio-pharmaceuticals with another 25 accelerators producing medically useful isotopes. These neutron-deficient isotopes are usually produced by proton bombardment. All commonly used medical isotopes can be generated by 'compact' cyclotrons with energies up to 40 MeV and beam intensities in the range 50 to 400 microamps. Specially designed target systems contain gram-quantities of highly enriched stable isotopes as starting materials. The targets can accommodate the high power densities of the proton beams and are designed for automated remote handling. The complete manufacturing cycle includes large-scale target production, isotope generation by cyclotron beam bombardment, radio-chemical extraction, pharmaceutical dispensing, raw material recovery, and labelling/packaging prior to the rapid delivery of these short-lived products. All these manufacturing steps adhere to the pharmaceutical industry standards of Good Manufacturing Practice (GMP). Unlike research accelerators, commercial cyclotrons are customized 'compact' machines usually supplied by specialist companies such as IBA (Belgium), EBCO (Canada) or Scanditronix (Sweden). The design criteria for these commercial cyclotrons are - small magnet dimensions, power-efficient operation of magnet and radiofrequency systems, high intensity extracted proton beams, well defined beam size and automated computer control. Performance requirements include rapid startup and shutdown, high reliability to support the daily production of short-lived isotopes and low maintenance to minimize the radiation dose to personnel. In 1987 a major step forward in meeting these exacting industrial requirements came when IBA, together with the University of Louvain-La-Neuve in Belgium, developed the Cyclone-30

Isotopic exchange between molecular hydrogen and liquid ammonia catalysed by alkali amides; Echange isotopique entre l'hydrogene moleculaire et l'ammoniac liquide catalyse par les amidures alcalins

Energy Technology Data Exchange (ETDEWEB)

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

1968-06-15

The catalytic action of alkali amides on the isotopic exchange between hydrogen and liquid ammonia has been reinvestigated. It was clear before this work that the reaction is homogeneous and first order with respect to the concentration of dissolved hydrogen, but the nature of the catalytic species was still subject to discussion. On one hand new precise kinetic measurements have been made with sodium, potassium, rubidium and cesium amide. On the other hand, the dissociation of these salts has been calculated with the help of the FUOSS-ONSAGER equation. If the rate of exchange is plotted as a function of the concentration of the free amide ion, a linear relationship is obtained. In our experimental conditions, primary salt effects are negligible and the concentration has to be used in the rate equations. This shows that only the free amide ion is acting as a catalytic species. Experiments on common ion effects and secondary salt effects support this conclusion. The results are in agreement with an associative mechanism. (author) [French] Une nouvelle etude de l'echange isotopique entre l'hydrogene et l'ammoniac liquide catalyse par les amidures alcalins a ete effectuee. II etait bien etabli avant le present travail que la reaction etait homogene et que sa vitesse etait du premier ordre par rapport a la concentration d'hydrogene dissous, mais la nature de l'espece catalytique etait encore controversee. De nouvelles mesures cinetiques precises ont ete faites avec les amidures de sodium, de potassium, de rubidium et de cesium. D'autre part, la dissociation de ces sels a ete calculee a l'aide de l'equation de FUOSS-ONSAGER. On constate que la vitesse d'echange est proportionnelle a la concentration de l'ion amidure libre. Dans nos conditions experimentales, les effets de sel primaires sont negligeables, l'equation de vitesse doit s'exprimer simplement en fonction des concentrations. Ceci indique que l'ion amidure libre est la seule espece catalytique. Des experiences d

Isotope separation apparatus

International Nuclear Information System (INIS)

Lyon, R.K.; Eisner, P.N.; Thomas, W.R.I.

1983-01-01

This application discloses a method for and an apparatus in which isotopes of an element in a compared are separated from each other while that compound, i.e., including a mixture of such isotopes, flows along a predetermined path. The apparatus includes a flow tube having a beginning and an end. The mixture of isotopes is introduced into the flow tube at a first introduction point between the beginning and the end thereof to flow the mixture toward the end thereof. A laser irradiates the flow tube dissociating compounds of a preselected one of said isotopes thereby converting the mixture in an isotopically selective manner. The dissociation products are removed from the tube at a first removal point between the first introduction point and the end. The dissociation product removed at the the first removal point are reconverted back into the comound thereby providing a first stage enriched compound. This first stage enriched compound is reintroduced into the flow tube at a second introduction point between the beginning thereof and the first introduction point. Further product is removed from the flow tube at a second removal point between the second introduction point and the first introduction point. The second introduction point is chosen so that the isotope composition of the first stage enriched compound is approximately the same as that of the compound in the flow tube

Calcium Isotope Analysis by Mass Spectrometry

Science.gov (United States)

Boulyga, S.; Richter, S.

2010-12-01

The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. This presentation discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. Additionally, the availability of Ca isotope reference materials will be discussed.

Ultracold Mixtures of Rubidium and Ytterbium for Open Quantum System Engineering

Science.gov (United States)

2014-06-01

species can be vanishing. 2.4.1 Miscibility Even at ultracold temperatures , our trapped gasses are very dilute. On the high side of achievable densities...essentially ideal. Therefore, any combination of isotopes will mix at high enough temperatures . Close to degeneracy, miscibility depends on the strength of...bakeout temperature is 200 ◦C, while the braze alloy melts at 305 ◦C. Custom dielectric AR coatings were designed and applied by Spectrum Thin Films

Isotopically exchangeable phosphorus

International Nuclear Information System (INIS)

Barbaro, N.O.

1984-01-01

A critique revision of isotope dilution is presented. The concepts and use of exchangeable phosphorus, the phosphate adsorption, the kinetics of isotopic exchange and the equilibrium time in soils are discussed. (M.A.C.) [pt

Rubidium distribution at atomic scale in high efficient Cu(In,Ga)Se2 thin-film solar cells

Science.gov (United States)

Vilalta-Clemente, Arantxa; Raghuwanshi, Mohit; Duguay, Sébastien; Castro, Celia; Cadel, Emmanuel; Pareige, Philippe; Jackson, Philip; Wuerz, Roland; Hariskos, Dimitrios; Witte, Wolfram

2018-03-01

The introduction of a rubidium fluoride post deposition treatment (RbF-PDT) for Cu(In,Ga)Se2 (CIGS) absorber layers has led to a record efficiency up to 22.6% for thin-film solar cell technology. In the present work, high efficiency CIGS samples with RbF-PDT have been investigated by atom probe tomography (APT) to reveal the atomic distribution of all alkali elements present in CIGS layers and compared with non-treated samples. A Scanning Electron Microscopy Dual beam station (Focused Ion Beam-Gas Injection System) as well as Transmission Kikuchi diffraction is used for atom probe sample preparation and localization of the grain boundaries (GBs) in the area of interest. The analysis of the 3D atomic scale APT reconstructions of CIGS samples with RbF-PDT shows that inside grains, Rb is under the detection limit, but the Na concentration is enhanced as compared to the reference sample without Rb. At the GBs, a high concentration of Rb reaching 1.5 at. % was found, and Na and K (diffusing from the glass substrate) are also segregated at GBs but at lower concentrations as compared to Rb. The intentional introduction of Rb leads to significant changes in the chemical composition of CIGS matrix and at GBs, which might contribute to improve device efficiency.

Physics with isotopically controlled semiconductors

International Nuclear Information System (INIS)

Haller, E.E.

1994-08-01

Control of the isotopic composition of semiconductors offers a wide range of new scientific opportunities. In this paper a number of recent results obtained with isotopically pure as well as deliberately mixed diamond and Ge bulk single crystals and Ge isotope superlattices will be reviewed. Isotopic composition affects several properties such as phonon energies, bandstructure and lattice constant in subtle but theoretically well understood ways. Large effects are observed for thermal conductivity, local vibrational modes of impurities and after neutron transmutation doping (NTD). Several experiments which could profit greatly from isotope control are proposed

Isotopic separation by ion chromatography

International Nuclear Information System (INIS)

Albert, M.G.; Barre, Y.; Neige, R.

1994-01-01

The isotopic exchange reaction and the isotopic separation factor are first recalled; the principles of ion chromatography applied to lithium isotope separation are then reviewed (displacement chromatography) and the process is modelled in the view of dimensioning and optimizing the industrial process; the various dimensioning parameters are the isotopic separation factor, the isotopic exchange kinetics and the material flow rate. Effects of the resin type and structure are presented. Dimensioning is also affected by physico-chemical and hydraulic parameters. Industrial implementation features are also discussed. 1 fig., 1 tab., 5 refs

Beneficial use of isotopes

International Nuclear Information System (INIS)

Bertel, E.; Stevens, G.H.

1998-01-01

The paper gives an outlook on the main isotopes currently used for beneficial applications, provides an overview on geographic distribution of isotope production capabilities and identifies the main suppliers world-wide. It analyses trends in different countries and regions, including the refurbishment and/or replacement of ageing facilities and the implementation of new capabilities. Issues related to adequate supply of isotopes and potential under or over capacity of production for some key products are discussed. The evolution of the isotope production sector is analysed. Issues such as lowering of governmental support to production facilities, emergence of international co-operation and agreements on production capabilities, and developments in non-OECD/NEA countries are addressed. The paper offers some concluding remarks on the importance of maintaining and enhancing beneficial uses of isotopes, the role of government policies, the need for co-operation between countries and between the private and public sectors. The paper addresses the role of international cooperation in making efficient use of existing isotope production capacity and investigates ways for reducing the need for investment in additional capacity. (author)

Isotopes Project

International Nuclear Information System (INIS)

Dairiki, J.M.; Browne, E.; Firestone, R.B.; Lederer, C.M.; Shirley, V.S.

1984-01-01

The Isotopes Project compiles and evaluates nuclear structure and decay data and disseminates these data to the scientific community. From 1940-1978 the Project had as its main objective the production of the Table of Isotopes. Since publication of the seventh (and last) edition in 1978, the group now coordinates its nuclear data evaluation efforts with those of other data centers via national and international nuclear data networks. The group is currently responsible for the evaluation of mass chains A = 167-194. All evaluated data are entered into the International Evaluated Nuclear Structure Data File (ENSDF) and are published in Nuclear Data Sheets. In addition to the evaluation effort, the Isotopes Project is responsible for production of the Radioactivity Handbook

Interaction of xenon difluoride with the fluorocomplexes of lanthanides and rubidium of the Rb/sub 3/M/sup 3/F/sub 6/ composition

Energy Technology Data Exchange (ETDEWEB)

Goryachenkov, S.A.; Fadeeva, N.E.; Kiselev, Yu.M.; Martynenko, L.I.; Spitsyn, V.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

The possibility of preparing rubidium fluorocomplexes of tetravalent lanthanides of the Rb/sub 3/M/sup 4/F/sub 7/ composition from Rb/sub 3/M/sup 3/F/sub 6/ (M/sup 3/=Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb) with XeF/sub 2/ has been studied. By the DTA method it is shown that Ce and Pr salts are fluorinated respectively at approximately 100 and approximately 235 deg C with a noticeable exoeffect. Tb and Dy salts fluorination proceeds with considerable kinetic difficulties. The fluorination products composition, Rb/sub 3/M/sup 4/F/sub 7/ (M/sup 4/=Ce, Pr, Tb, Dy) is confirmed by the methods of chemical, IR-spectroscopic and X-ray phase analyses. XeF/sub 2/ interaction with Rb/sub 3/M/sup 3/F/sub 6/ salts of other lanthanides up to 400 deg C has not been observed.

Evaluating the skills of isotope-enabled general circulation models against in situ atmospheric water vapor isotope observations

DEFF Research Database (Denmark)

Steen-Larsen, Hans Christian; Risi, C.; Werner, M.

2017-01-01

The skills of isotope-enabled general circulation models are evaluated against atmospheric water vapor isotopes. We have combined in situ observations of surface water vapor isotopes spanning multiple field seasons (2010, 2011, and 2012) from the top of the Greenland Ice Sheet (NEEM site: 77.45°N......: 2014). This allows us to benchmark the ability to simulate the daily water vapor isotope variations from five different simulations using isotope-enabled general circulation models. Our model-data comparison documents clear isotope biases both on top of the Greenland Ice Sheet (1-11% for δ18O and 4...... boundary layer water vapor isotopes of the Baffin Bay region show strong influence on the water vapor isotopes at the NEEM deep ice core-drilling site in northwest Greenland. Our evaluation of the simulations using isotope-enabled general circulation models also documents wide intermodel spatial...

Stable isotope enrichment: Current and future potential

International Nuclear Information System (INIS)

Tracy, J.G.; Aaron, W.S.

1992-01-01

Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities

Stable isotope enrichment - current and future potential

International Nuclear Information System (INIS)

Tracy, J.G.; Aaron, W.S.

1993-01-01

Oak Ridge National Laboratory (ORNL) operates the Isotope Enrichment Facility for the purpose of providing enriched stable isotopes, selected radioactive isotopes (including the actinides), and isotope-related materials and services for use in various research applications. ORNL is responsible for isotope enrichment and the distribution of approximately 225 nongaseous stable isotopes from 50 multi-isotopic elements. Many enriched isotope products are of prime importance in the fabrication of nuclear targets and the subsequent production of special radionuclides. State-of-the-art techniques to achieve special isotopic, chemical, and physical requirements are performed at ORNL. This report describes the status and capabilities of the Isotope Enrichment Facility and the Isotope Research Materials Laboratory as well as emphasizing potential advancements in enrichment capabilities. (orig.)

Stable Isotope Group 1982 progress report

International Nuclear Information System (INIS)

Stewart, M.K.

1983-06-01

The work of the Stable Isotope Group of the Institute of Nuclear Sciences during 1982, in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and mass spectrometer instrumentation, is described

Isotopic marking and tracers

International Nuclear Information System (INIS)

Morel, F.

1997-01-01

The use of radioactive isotopes as tracers in biology has been developed thanks to the economic generation of the required isotopes in accelerators and nuclear reactors, and to the multiple applications of tracers in the life domain; the most usual isotopes employed in biology are carbon, hydrogen, phosphorus and sulfur isotopes, because these elements are present in most of organic molecules. Most of the life science knowledge appears to be dependent to the extensive use of nuclear tools and radioactive tracers; the example of the utilization of radioactive phosphorus marked ATP to study the multiple reactions with proteins, nucleic acids, etc., is given

Boron isotopes in geothermal systems

International Nuclear Information System (INIS)

Aggarwal, J.

1997-01-01

Boron is a highly mobile element and during water-rock reactions, boron is leached out of rocks with no apparent fractionation. In geothermal systems where the water recharging the systems are meteoric in origin, the B isotope ratio of the geothermal fluid reflects the B isotope ratio of the rocks. Seawater has a distinctive B isotope ratio and where seawater recharges the geothermal system, the B isotope ratio of the geothermal system reflects the mixing of rock derived B and seawater derived B. Any deviations of the actual B isotope ratio of a mixture reflects subtle differences in the water-rock ratios in the cold downwelling limb of the hydrothermal system. This paper will present data from a variety of different geothermal systems, including New Zealand; Iceland; Yellowston, USA; Ibusuki, Japan to show the range in B isotope ratios in active geothermal systems. Some of these systems show well defined mixing trends between seawater and the host rocks, whilst others show the boron isotope ratios of the host rock only. In geothermal systems containing high amounts of CO 2 boron isotope ratios from a volatile B source can also be inferred. (auth)

Isotopes in Greenland Precipitation

DEFF Research Database (Denmark)

Faber, Anne-Katrine

Greenland ice cores offer a unique opportunity to investigate the climate system behaviour. The objective of this PhD project is to investigate isotope modelling of present- day conditions and conduct model-data comparison using Greenland ice cores. Thus this thesis investigates how the integration...... of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2......) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland. The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3...

Isotope separation process

International Nuclear Information System (INIS)

1976-01-01

The invention relates to a process for separating a given material into two or more parts, in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in the said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase UF 6 by infrared photon absorption followed by selective reaction of said excited UF 6 with atomic chlorine, bromine, or iodine to form a product which may be separated by means known in the art

Pb isotopes of Gorgona Island (Colombia): Isotopic variations correlated with magma type

International Nuclear Information System (INIS)

Dupre, B.; Echeverria, L.M.

1984-01-01

Lead isotopic results obtained on komatiites and basalts from Gorgona Island provide evidence of large isotopic variations within a restricted area (8x2.5 km). The variations are correlated with differences in volcanic rock type. The highest isotopic ratios ( 206 Pb/ 204 Pbproportional19.75) correspond to tholeiites which make up most of the island. The lowest ratios (18.3) correspond to the komatiites of the west coast of the island. Other rock types (komatiites of the east coast, K-tholeiites, picrites and tuffs) have isotopic characteristics intermediate between these two extreme values. These results are explained by the existence of two distinct mantle sourbe regions, and by mixing or contamination between them. (orig.)

Pb isotopes of Gorgona Island (Colombia): isotopic variations correlated with magma type

Science.gov (United States)

Dupré, B.; Echeverría, L. M.

1984-02-01

Lead isotopic results obtained on komatiites and basalts from Gorgona Island provide evidence of large isotopic variations within a restricted area (8 × 2.5 km). The variations are correlated with differences in volcanic rock type. The highest isotopic ratios ( 206Pb/ 204Pb˜ 19.75 ) correspond to tholeiites which make up most of the island. The lowest ratios (18.3) correspond to the komatiites of the west coast of the island. Other rock types (komatiites of the east coast, K-tholeiites, picrites and tuffs) have isotopic characteristics intermediate between these two extreme values. These results are explained by the existence of two distinct mantle source regions, and by mixing or contamination between them.

Stable Isotope Group 1983 progress report

International Nuclear Information System (INIS)

Stewart, M.K.

1984-06-01

The work of the Stable Isotope Group of the Institute of Nuclear Sciences in the fields of isotope geology, isotope hydrology, geochronology, isotope biology and related fields, and mass spectrometer instrumentation, during 1983, is described

Hot vacuum extraction-isotopic dilution mass spectrometry for determination of hydrogen isotopes in zircaloys

International Nuclear Information System (INIS)

Shi, Y.; Leeson, P.K.; Wilkin, D.; Britton, A.; Macleod, R.

2016-01-01

A hot vacuum extraction-isotope dilution mass spectrometry (HVE-IDMS) was studied for determination of hydrogen isotopes in zirconium metal and alloys as nuclear reactor materials. A theoretical assessment of the completeness of the extraction of hydrogen isotopes under the chosen condition was carried out based on the hydrogen and deuterium solubility data for zirconium. The optimal isotopic spiking condition for conventional IDMS was further explored for the special case IDMS where the isotope abundance of the samples is varied and non-natural. Applying the optimal conditions, the accurate IDMS determination was realized. The agreement between the measured values and the certified or prepared values of standard reference materials and homemade standard materials validate the method developed. (author)

Isotopic exchange reactions. Kinetics and efficiency of the reactors using them in isotopic separation

International Nuclear Information System (INIS)

Ravoire, Jean

1979-11-01

In the first part, some definitions and the thermodynamic and kinetic isotopic effect concepts are recalled. In the second part the kinetic laws are established, in homogeneous and heterogeneous medium (one component being on occasions present in both phases), without and with isotopic effects. Emphasis is put on application to separation of isotopes, the separation factor α being close to 1, one isotope being in large excess with respect to the other one. Isotopic transfer is then given by: J = Ka (x - y/α) where x and y are the (isotopic) mole fractions in both phases, Ka may be either the rate of exchange or a transfer coefficient which can be considered as the 'same in both ways' if α-1 is small compared to the relative error on the measure of Ka. The third part is devoted to isotopic exchange reactors. Relationships between their efficiency and kinetics are established in some simple cases: plug cocurrent flow reactors, perfectly mixed reactors, countercurrent reactors without axial mixing. We treat only cases where α and the up flow to down flow ratio is close to 1 so that Murphee efficiency approximately overall efficiency (discrete stage contactors). HTU (phase 1) approximately HTU (phase 2) approximately HETP (columns). In a fourth part, an expression of the isotopic separative power of reactors is proposed and discussed [fr

Great isotope effects in compounding of sodium isotopes by macrocyclic polyether

International Nuclear Information System (INIS)

Knoechel, A.; Wilken, R.D.

1978-01-01

Isotope effects appear in the compounding of the two sodium isotopes 24 Na + and 22 Na + with macrocyclic polyethers, whose value was determined for the 13 best known polyethers. A radiometric process was used for determining the different half life periods of the nuclides used. To separate the compound and non-compound types, these were distributed between water and chloroform. The isotope ratio in the chloroform phase was compared with the output isotope ratio and the separation facfor determined from this. When using crown ethers, there was enrichment of 24 Na + by a significant amount (large crown ether) up to 3.1 +- 0.4% for 18 crown 6. The remarkably high results can be correlated by Biegeleisen's theory with other chemical conditions. There is a report on the first results of transferring these conditions to the H + /T + system. (orig.) [de

Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange

International Nuclear Information System (INIS)

Jepson, B.E.; Shockey, G.C.

1984-01-01

The enrichment of calcium isotopes has been observed in ion-exchange chromatography with an aqueous phase of calcium hydroxide and a solid phase of sulfonic acid resin. The band front was exceedingly sharp as a result of the acid-base reaction occuring at the front of the band. Single-stage separation coefficients were found to be epsilon( 44 Ca/ 40 Ca) = 11 x 10 -4 and epsilon( 48 Ca/ 40 Ca) = 18 x 10 -4 . The maximum column separation factors achieved were 1.05 for calcium-44 and 1.09 for calcium-48 with the heavy isotopes enriching in the fluid phase. The calcium isotope effect between fully hydrated aqueous calcium ions and undissociated aqueous calcium hydroxide was estimated. For the calcium-44/40 isotope pair the separation coefficient was 13 x 10 -4 . 20 references, 2 figures

Pb isotopes of Gorgona Island (Colombia): Isotopic variations correlated with magma type

Energy Technology Data Exchange (ETDEWEB)

Dupre, B.; Echeverria, L.M. (Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany, F.R.))

1984-02-01

Lead isotopic results obtained on komatiites and basalts from Gorgona Island provide evidence of large isotopic variations within a restricted area (8x2.5 km). The variations are correlated with differences in volcanic rock type. The highest isotopic ratios (/sup 206/Pb//sup 204/Pb proportional 19.75) correspond to tholeiites which make up most of the island. The lowest ratios (18.3) correspond to the komatiites of the west coast of the island.

Isotope analytics for the evaluation of the feeding influence on the isotope ratio in beef samples

International Nuclear Information System (INIS)

Herwig, Nadine

2010-01-01

Information about the origin of food and associated production systems has a high significance for food control. An extremely promising approach to obtain such information is the determination of isotope ratios of different elements. In this study the correlation of the isotope ratios C-13/C-12, N-15/N-14, Mg-25/Mg-24, and Sr-87/Sr-86 in bovine samples (milk and urine) and the corresponding isotope ratios in feed was investigated. It was shown that in the bovine samples all four isotope ratios correlate with the isotope composition of the feed. The isotope ratios of strontium and magnesium have the advantage that they directly reflect the isotope ratios of the ingested feed since there is no isotope fractionation in the bovine organism which is in contrast to the case of carbon and nitrogen isotope ratios. From the present feeding study it is evident, that a feed change leads to a significant change in the delta C-13 values in milk and urine within 10 days already. For the deltaN-15 values the feed change was only visible in the bovine urine after 49 days. Investigations of cows from two different regions (Berlin/Germany and Goestling/Austria) kept at different feeding regimes revealed no differences in the N-15/N-14 and Mg-26/Mg-24 isotope ratios. The strongest correlation between the isotope ratio of the bovine samples and the kind of ingested feed was observed for the carbon isotope ratio. With this ratio even smallest differences in the feed composition were traceable in the bovine samples. Since different regions usually coincide with different feeding regimes, carbon isotope ratios can be used to distinguish bovine samples from different regions if the delta C-13 values of the ingested feed are different. Furthermore, the determination of strontium isotope ratios revealed significant differences between bovine and feed samples of Berlin and Goestling due to the different geologic realities. Hence the carbon and strontium isotope ratios allow the best

Isotope Exchange: a Potential Mechanism Regulating the Natural and Anthropogenic Pb Isotope Budget in Coastal Waters

Science.gov (United States)

Chen, M.; Boyle, E. A.; Zurbrick, C.; Carrasco, G. G.; Switzer, A.; Zhao, N.

2016-02-01

Two independent studies on anthropogenic Pb and Pb isotopes in coastal corals from the northern Arabian Gulf and the Singapore Straits have shown an isotopic excursion where the main Pb sources discharging to the water move to more crustal-like values, indicating that the Pb in coastal waters might exchange isotopically with crustal particulates without propotional change in concentration. To investigate this issue, Pb isotope exchange is assessed through a closed-system exchange experiment using estuarine waters collected at the Johor River mouth (discharging to the Singapore Straits). During the experiment, a known amount of NBS-981 (206Pb/207Pb=1.093) was spiked into the unfiltered Johor water (dissolved 206Pb/207Pb = 1.199) and the changing isotopic composition of the dissolved Pb was monitored. Shortly after the spike addition, dissolved Pb exhibited 206Pb/207Pb=1.178, reflecting the influence of the spike. Within the following few days, the 206Pb/207Pb in the water increased to >1.190 with limited changes of the dissolved Pb concentration. The observations in closed-system experiment agree with the isotope difference between Singapore aerosol and seawater in our 2-year-long field observations. The kinetics of isotope exchange were assessed using a simple model, which reproduced >70% of the observed Pb isotope variance. Both the close-system experiment and field measurements imply that isotope exchange can be an important mechanism for regulating the Pb and Pb isotopes in coastal waters. Investigations on the distribution of Pb and Pb isotope in estuaries and coastal waters should further assess the role of isotope exchange in ocean Pb chemistry.

Techniques for preparing isotopic targets

International Nuclear Information System (INIS)

Xu Guoji; Guan Shouren; Luo Xinghua; Sun Shuhua

1987-12-01

The techniques of making isotopic targets for nuclear physics experiments are introduced. Vacuum evaporation, electroplating, centrifugal precipitation, rolling and focused heavy-ion beam sputtering used to prepare various isotopic targets at IAE are described. Reduction-distillation with active metals and electrolytic reduction for converting isotope oxides to metals are mentioned. The stripping processes of producing self-supporting isotopic targets are summarized. The store methods of metallic targets are given

Isotope applications in the environmental field

International Nuclear Information System (INIS)

DeWitt, R.

1978-01-01

Established uses of enriched isotopes in the environmental field were surveyed to determine future trends in isotope needs. Based on established isotope uses, on the projected increase in the pollution problem, and on the apparent social and economic pressure for pollution abatement, a significant demand for enriched isotopes appears to be developing for the assessment and control of air, water, and soil pollutants. Isotopic techniques will be used in combination with conventional methods of detection and measurement, such as gas chromatography, x-ray fluorescence, and atomic absorption. Recent advances in economical isotope separation methods, instrumentation, and methodology promise to place isotopic technology within the reach of most research and industrial institutions. Increased application of isotope techniques appears most likely to occur in areas where data are needed to characterize the movement, behavior, and fate of pollutants in the environment

Isotopic contamination in electromagnetic isotope separators; La contagion isotopique dans les separateurs electromagnetiques d'isotopes

Energy Technology Data Exchange (ETDEWEB)

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

1960-07-01

The mechanisms producing isotopic contamination in the electromagnetic separation of isotopes are studied with the aid of the Separator of Saclay and an electrostatic analyzer in cascade. After a separate investigation the result of which is that no contamination comes from the spreading of initial energies of ions, two principal mechanisms are emphasized; scattering and instability of the regime of the sources. The characters of each type of contamination arising from both mechanisms are described in some detail. An unique scheme of isotopic contamination is then derived from the partial ones. This scheme is successfully verified in several experimental separations. The applications concern principally the performances of magnetic cascades and more complex apparatus. It is found that the isotopic purities that such machines can deliver are extremely high. (author) [French] On a etudie, a l'aide du separateur de Saclay et d'un analyseur electrostatique en cascade, les mecanismes par lesquels est produite la contamination isotopique dans la separation electromagnetique des isotopes. A la suite d'une deuxieme etude, qui a mene a la conclusion que la contamination ne provient pas d'une dispersion des energies initiales des ions, on propose deux mecanismes comme etant les plus importants; la diffusion et l'instabilite du regime des sources. On decrit en quelques details la nature de la contamination provenant de deux types de mecanisme. On deduit de ces deux mecanismes un seul schema qui a ete ensuite verifie par plusieurs separations experimentales. Les applications interessent surtout les performances des cascades magnetiques et les appareillages plus complexes. On trouve que les puretes isotopiques que peuvent fournir de tels appareils sont tres elevees. (auteur)

Isotope dilution analysis

Energy Technology Data Exchange (ETDEWEB)

Fudge, A.

1978-12-15

The following aspects of isotope dilution analysis are covered in this report: fundamental aspects of the technique; elements of interest in the nuclear field, choice and standardization of spike nuclide; pre-treatment to achieve isotopic exchange and chemical separation; sensitivity; selectivity; and accuracy.

Discovery of the cadmium isotopes

International Nuclear Information System (INIS)

Amos, S.; Thoennessen, M.

2010-01-01

Thirty-seven cadmium isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

Discovery of the iron isotopes

International Nuclear Information System (INIS)

Schuh, A.; Fritsch, A.; Heim, M.; Shore, A.; Thoennessen, M.

2010-01-01

Twenty-eight iron isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

Discovery of the silver isotopes

International Nuclear Information System (INIS)

Schuh, A.; Fritsch, A.; Ginepro, J.Q.; Heim, M.; Shore, A.; Thoennessen, M.

2010-01-01

Thirty-eight silver isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

Isotopes in oxidation reactions

International Nuclear Information System (INIS)

Stewart, R.

1976-01-01

The use of isotopes in the study of organic oxidation mechanisms is discussed. The help provided by tracer studies to demonstrate the two-equivalent path - hydride transfer, is illustrated by the examples of carbonium oxidants and the Wacker reaction. The role of kinetic isotope effects in the study of the scission of carbon-hydrogen bonds is illustrated by hydride abstraction, hydrogen atom abstraction, proton abstraction and quantum mechanical tunnelling. Isotopic studies on the oxidation of alcohols, carbonyl compounds, amines and hydrocarbons are discussed. The role of isotopes in the study of biochemical oxidation is illustrated with a discussion on nicotinamide and flavin coenzymes. (B.R.H.)

Annual report 1980-1981

International Nuclear Information System (INIS)

Wilson, H.W.

1982-01-01

A review of the year 1980-1981 at the Scottish Universities Research and Reactor Centre. On the reactor side the new Ortec data acquisition and analysis system plus a new high efficiency, low background Ge detector system delivered during 1980-81 greatly increased the efficiency of radioactive measurements, the new detector alone providing a tenfold decrease in data processing time. A wide range of applications of radiochemistry in geology, medicine, biology, chemical reactions, industrial applications and other fields benefited from this. Two new mass spectrometers were installed in the Isotope Geology Unit. One (a VG Isomass 54E) for solid source samples, especially samarium, rubidium and strontium and the other (VG Micromass ''Siamese'' VG903) for stable isotope geochemistry studies of carbon, oxygen and hydrogen. Former office accommodation was converted for very low level environmental measurements. The projects and analyses undertaken are listed under the sections, Reactor related activities (physics, radiochemistry, health physics and nuclear medicine, computing and engineering), Isotope geology (solid source group, potassium argon laboratory, stable isotope geochemistry laboratory, uranium series geochronology) and NERC radiocarbon laboratory. (U.K.)

Lead isotope in mineral exploration

International Nuclear Information System (INIS)

Gulson, B.L.

1986-01-01

This book provides an up-to-date state-of-the-art review of lead isotopes in mineral exploration. Beginning with an historical review on suggested uses of lead isotopes in mineral exploration, the author then outlines the theoretical aspects of lead isotopes and illustrates that the method is based on well-known principles of radioactive decay, from which isotopic signatures for different styles of mineralization are derived. The varying isotopic signatures are then introduced. The major part of the book details over 40 case histories for base and precious metals, uranium and tin using sampling media such as sulfides, gossans, soils, weathered bedrock, vegetation and groundwaters. Advantages and disadvantages of each are discussed. Examples are given of the use of lead isotopes in testing conceptual models for exploration. The success rate and cost-effectiveness of the method are illustrated by actual exploration examples. Analytical advances which should lower the cost of the method and future uses are outlined. Many of the case histories use recently published or unpublished data, 27 tables of which are given in an appendix. Details of sampling, the methods for obtaining the isotope ratios, and a commercially-available integrated lead isotope service are also provided. (Auth.)

Isotope effects on chemical equilibria

International Nuclear Information System (INIS)

Golding, P.D.

1974-01-01

The thermodynamic equilibrium constants of three deuterated substituted acetic acids are reported. The calculation of secondary isotope effects of the second kind for the three isotopic acid pairs has been accomplished by the appropriate comparison of thermodynamic equilibrium constants, and by the comparison of isotopic slopes. The effect of substituent variation on the isotope effects reported here disqualifies the simple inductive model as a legitimate description of secondary isotope effects of the second kind. The correlation of diminishing isotope effect per deuterium atom with increasing acidity is also invalidated by the present results. The syntheses of 9-thia-9,10-dihydrophenanthrene-9-oxide and thioxanthene-10-oxide are described. These compounds have been partially deuterated at their respective methylene positions. Spectral evidence indicates stereoselectivity of the methylene protons in the exchange reactions of both compounds. (author)

Production and spectroscopy of ultracold YbRb{sup *} molecules

Energy Technology Data Exchange (ETDEWEB)

Nemitz, Nils

2008-11-15

This thesis describes the formation of electronically excited but translationally cold molecules formed from rubidium atoms and two isotopes of ytterbium ({sup 176}Yb and {sup 174}Yb) by means of photoassociation. The experiments were performed in a combined MOT with 10{sup 9} rubidium atoms and 2.10{sup 6} ytterbium atoms at temperatures of less than 1 mK. Photoassociation lines were found by trap loss spectroscopy throughout a wavelength range of 2 nm near the 795 nm D1 transition in rubidium. The majority of lines belong to two vibrational series in the excited YbRb{sup *} molecule, converging on a system of a ground state ytterbium atom and an excited rubidium atom. The strong variation of line strength between different vibrational lines is explained through the Franck-Condon principle. An improved version of the Leroy-Bernstein equation was used to extract the leading dispersion coefficient of the potential from the vibrational progression. Most of the observed lines show a resolved rotational structure as expected from a basic quantum mechanical model. The series terminates with the third or forth rotational component due to the ground state centrifugal barrier.The measured rotational constants agree very well with calculations based on the C{sub 6} coefficient. The discovery of a splitting of the rotational components into subcomponents indicates an uncommon angular momentum coupling described by Hund's case. Variations in the depth of the subcomponents indicates a similar splitting in the ground state, with the energies of the substates based on the alignment of the rubidium atom's magnetic dipole moment relative to the angular momentum carried by an approaching ytterbium atom. This creates an additional ground state barrier, partially suppressing some of the subcomponents. Using a rate equation model developed for this purpose, a maximum formation rate of 2.5.10{sup 6} molecules per second was calculated over the volume of the entire trap. The

Isotopic chirality

Energy Technology Data Exchange (ETDEWEB)

Floss, H.G. [Univ. of Washington, Seattle, WA (United States)

1994-12-01

This paper deals with compounds that are chiral-at least in part, due to isotope substitution-and their use in tracing the steric course of enzyme reaction in vitro and in vivo. There are other applications of isotopically chiral compounds (for example, in analyzing the steric course of nonenzymatic reactions and in probing the conformation of biomolecules) that are important but they will not be discussed in this context.

Isotopic separation

International Nuclear Information System (INIS)

Chen, C.L.

1982-01-01

A method is described for separating isotopes in which photo-excitation of selected isotope species is used together with the reaction of the excited species with postive ions of predetermined ionization energy, other excited species, or free electrons to produce ions or ion fragments of the selected species. Ions and electrons are produced by an electrical discharge, and separation is achieved through radial ambipolar diffusion, electrostatic techniques, or magnetohydrodynamic methods

Isotope enrichment

International Nuclear Information System (INIS)

Lydtin, H-J.; Wilden, R.J.; Severin, P.J.W.

1978-01-01

The isotope enrichment method described is based on the recognition that, owing to mass diffusion and thermal diffusion in the conversion of substances at a heated substrate while depositing an element or compound onto the substrate, enrichment of the element, or a compound of the element, with a lighter isotope will occur. The cycle is repeated for as many times as is necessary to obtain the degree of enrichment required

Isotope separation process

International Nuclear Information System (INIS)

Wexler, Sol; Young, C.E.

1976-01-01

Description is given of method for separating a specific isotope from a mixture of isotopes of an actinide element present as MF 6 , wherein M is the actinide element. It comprises: preparing a feed gas mixture of MF 6 in a propellant gas; passing the feed gas mixture under pressure through an expansion nozzle while heating the mixture to about 600 0 C; releasing the heated gas mixture from the nozzle into an exhaust chamber having a reduced pressure, whereby a gas jet of MF 6 molecules, MF 6 molecular clusters and propellant gas molecules is formed, the MF 6 molecules having a translational energy of about 3 eV; converting the MF 6 molecules to MF 6 ions by passing the jet through a cross jet of electron donor atoms so that an electron transfer takes place between the MF 6 - molecules and the electron donor atoms whereby the jet is now quasi-neutral, containing negative MF 6 - ions and positive donor ions; passing the quasi-neutral jet through a radiofrequency mass filter tuned to separate the MF 6 ions containing the specific isotope from the MF 6 - ions of the other isotopes and neutralizing and collecting the MF 6 molecules of the specific isotope [fr

Measurement of Na-K-ATPase-mediated rubidium influx in single segments of rat nephron

Energy Technology Data Exchange (ETDEWEB)

Cheval, L.; Doucet, A. (Centre National de la Recherche Scientifique, Paris (France))

1990-07-01

To determine the functioning rate of Na-K-ATPase in the rat nephron, a micromethod was developed to measure the rate of rubidium uptake in single nephron segments microdissected from collagenase-treated kidneys. Because the hydrolytic activity of Na-K-ATPase displayed the same apparent affinity for K and Rb ions, whereas the Vmax elicited by K was higher than that in the presence of Rb, experiments were performed in the presence of cold Rb plus 86Rb. Before the assay, tubules were preincubated for 10 min at 37 degrees C to restore the normal transmembrane cation gradients. 86Rb uptake was measured after washing out extracellular cations by rinsing the tubules in ice-cold choline chloride solution containing Ba2+. Rb uptake increased quasi-linearly as a function of incubation time up to 30 s in the thick ascending limb, 1 min in the proximal convoluted tubule, and 5 min in the collecting tubule, and reached an equilibrium after 5-30 min. The initial rates of Rb uptake increased in a saturable fashion as Rb concentration in the medium rose from 0.25 to 5 mM. In medullary thick ascending limb, the initial rate of Rb uptake was inhibited by greater than 90% by 2.5 mM ouabain and by 10(-5) M of the metabolic inhibitor carbonyl cyanide trifluoromethoxyphenylhydrazone. Correlation of Na-K-ATPase hydrolytic activity at Vmax and initial rates of ouabain-sensitive Rb uptake in the successive segments of nephron indicates that in intact cells the pump works at approximately 20-30% of its Vmax. Increasing intracellular Na concentration by tubule preincubation in a Rb- and K-free medium increased the initial rates of Rb intake up to the Vmax of the hydrolytic activity of the pump.

Measurement of Na-K-ATPase-mediated rubidium influx in single segments of rat nephron

International Nuclear Information System (INIS)

Cheval, L.; Doucet, A.

1990-01-01

To determine the functioning rate of Na-K-ATPase in the rat nephron, a micromethod was developed to measure the rate of rubidium uptake in single nephron segments microdissected from collagenase-treated kidneys. Because the hydrolytic activity of Na-K-ATPase displayed the same apparent affinity for K and Rb ions, whereas the Vmax elicited by K was higher than that in the presence of Rb, experiments were performed in the presence of cold Rb plus 86Rb. Before the assay, tubules were preincubated for 10 min at 37 degrees C to restore the normal transmembrane cation gradients. 86Rb uptake was measured after washing out extracellular cations by rinsing the tubules in ice-cold choline chloride solution containing Ba2+. Rb uptake increased quasi-linearly as a function of incubation time up to 30 s in the thick ascending limb, 1 min in the proximal convoluted tubule, and 5 min in the collecting tubule, and reached an equilibrium after 5-30 min. The initial rates of Rb uptake increased in a saturable fashion as Rb concentration in the medium rose from 0.25 to 5 mM. In medullary thick ascending limb, the initial rate of Rb uptake was inhibited by greater than 90% by 2.5 mM ouabain and by 10(-5) M of the metabolic inhibitor carbonyl cyanide trifluoromethoxyphenylhydrazone. Correlation of Na-K-ATPase hydrolytic activity at Vmax and initial rates of ouabain-sensitive Rb uptake in the successive segments of nephron indicates that in intact cells the pump works at approximately 20-30% of its Vmax. Increasing intracellular Na concentration by tubule preincubation in a Rb- and K-free medium increased the initial rates of Rb intake up to the Vmax of the hydrolytic activity of the pump

Isotope-equipped measuring instruments

International Nuclear Information System (INIS)

Miyagawa, Kazuo; Amano, Hiroshi

1980-01-01

In the steel industry, though the investment in isotope-equipped measuring instruments is small as compared with that in machinery, they play important role in the moisture measurement in sintering and blast furnaces, the thickness measurement in rolling process and others in automatic control systems. The economic aspect of the isotope-equipped measuring instruments is described on the basis of the practices in Kimitsu Works of Nippon Steel Corporation: distribution of such instruments, evaluation of economic effects, usefulness evaluation in view of raising the accuracy, and usefulness evaluation viewed from the failure of the isotope instruments. The evaluation of economic effects was made under the premise that the isotope-equipped measuring instruments are not employed. Then, the effects of raising the accuracy are evaluated for a γ-ray plate thickness gauge and a neutron moisture gauge for coke in a blast furnace. Finally, the usefulness was evaluated, assuming possible failure of the isotope-equipped measuring instruments. (J.P.N.)

The measurement of the isotope ratios and concentrations of zinc by thermal ionization mass spectrometry using double isotope dilution

International Nuclear Information System (INIS)

Deng Zhongguo

1994-01-01

The isotope ratios and concentrations of zinc are measured by silicagel-thermal ionization mass spectrometry using the double isotope spikers. The double isotope spikers ( 70 Zn and 67 Zn-enriched isotopes) are used to correct the isotope mass fractionation for the zinc isotope ratios, and to certify the zinc concentrations in the unknown samples. The zinc concentrations of these double isotope spikers are surveyed by a spiker made of pure (99.99%) natural zinc metal powder. The correcting factors (f a , f t and f n ) of the zinc isotope ratios in the spiked mixture, spike and unspiked samples for the isotope mass fractionation, and the spike-to-unspiked ratios (X r ) of the zinc isotope r in the spiked mixture samples can be obtained to solve the matrix equations by numerical approximation. The natural zinc isotope ratios are: 64 Zn/ 67 Zn = 11.8498, 66 Zn/ 67 Zn = 6.7977, 68 Zn/ 67 Zn = 4.5730 and 70 Zn/ 67 Zn = 0.1520. The uncertainties determined of the isotope ratios and concentrations of zinc are +- 0.16% and +-0.31%, respectively

General physical fundamentals of isotope hydrology

International Nuclear Information System (INIS)

Moser, H.; Rauert, W.

1976-01-01

A description is given of the measurement and measuring units of stable isotopes, the physical properties, measurement and measuring units of radioactive isotopes, the fundamentals of the tracer technique, the environmental isotope distribution in the hydrosphere and the radiation protection in isotope hydrological investigations. (HK) [de

Isotope separation by ion waves

International Nuclear Information System (INIS)

Dawson, J.M.

1978-01-01

One of the isotopes of an element having several isotopes can be separated from the others in a dense, neutral plasma. Thus initially a neutral plasma is prepared including the element in question. This may consist of positive ions and negative electrons or alternatively of positive and negative ions, or else of a mixture of positive ions, negative ions and electrons. The plasma may then be injected into a magnetic field or may be generated in the field where more energy is imparted to a selected isotope than to the others. Finally, the isotopes are separated from each other on the basis of their differential energies. For example, the selected isotope may be given more energy than the others by stimulating it within the plasma at its resonant frequency which may be close to the cyclotron frequency, either by an electric field or by a magnetic field. In order to excite the other isotope, a different resonant frequency is required which depends on the plasma density, the relative concentration of electrons if the plasma contains electrons, the strength of the magnetic field, the ratio of charge to mass of the isotope, and possibly on the physical parameters of the plasma apparatus itself, such as the ratio of the length of the plasma column to its radius. The more energetic isotope may be separated by energy dependent chemical reactions, it may be collected by a positively biased probe or else the isotopes may be separated from each other by magnetic fields or in various other ways

Isotope separation by magnetic fields

International Nuclear Information System (INIS)

Dawson, J.M.

1978-01-01

One of the isotopes of an element having several isotopes can be separated from the others in a dense, neutral plasma. Thus initially a neutral plasma is prepared including the element in question. This may consist of positive ions and negative electrons or alternatively of positive and negative ions, or else of a mixture of positive ions, negative ions and electrons. The plasma may then be injected into a magnetic field or may be generated in the field where more energy is imparted to a selected isotope than to the others. Finally, the isotopes are separated from each other on the basis of their differential energies. For example, the selected isotope may be given more energy than the others by stimulating it within the plasma at its resonant frequency which may be close to the cyclotron frequency, either by an electric field or by a magnetic field. In order to excite the other isotope, a different resonant frequency is required which depends on the plasma density, the relative concentration of electrons if the plasma contains electrons, the strength of the magnetic field, the ratio of charge to mass of the isotope, and possibly on the physical parameters of the plasma apparatus itself, such as the ratio of the length of the plasma column to its radius. The more energetic isotope may be separated by energy dependent chemical reactions, it may be collected by a positively biased probe or else the isotopes may be separated from each other by magnetic fields or in various other ways

Laser spectroscopy of the 5P3/2 → 6Pj (j = 1/2 and 3/2) electric dipole forbidden transitions in atomic rubidium

Science.gov (United States)

Ponciano-Ojeda, F.; Hernández-Gómez, S.; Mojica-Casique, C.; Hoyos, L. M.; Flores-Mijangos, J.; Ramírez-Martínez, F.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J.

2018-04-01

Doppler-free optical double-resonance spectroscopy is used to study the 5S1/2 → 5P3/2 → 6Pj (j = 3/2,1/2) excitation sequence in room-temperature rubidium atoms. This involves a 5S1/2 → 5P3/2 electric dipole preparation step followed by the 5P3/2 → 6Pj electric quadrupole excitation. The electric dipole forbidden transitions occur at 911.0 nm (j = 3/2) and 917.5 nm (j = 1/2). Production of atoms in the 6Pj states is detected by observing their direct decay to the ground state through emission of blue photons (λ ≈ 420 nm). A detailed experimental and theoretical study of the dependence on the relative linear polarizations of excitation beams is made. It is shown that specific electric quadrupole selection rules over magnetic quantum numbers are directly related to the relative orientation of the linear polarization of the excitation beams.

Isotope distribution program at the Oak Ridge National Laboratory with emphasis on medical isotopes

International Nuclear Information System (INIS)

Adair, H.L.

1987-01-01

The Isotope Distribution Program (IDP) is a group of individual activities with separate and diverse DOE sponsors which share the common mission of the production and distribution of isotope products and the performance of isotope-related services. Its basic mission is to provide isotope products and associated services to the user community by utilizing government-owned facilities that are excess to the primary mission of the DOE. The IDP is in its 41st year of operation. Initially, the program provided research quantities of radioactive materials, and through the 1950's it was the major supplier of radioisotopes for both research and commercial application. Distribution of enriched stable isotopes began in 1954. This paper discusses the use of radioisotopes in medicine and the role that ORNL plays in this field

Stable water isotope patterns in a climate change hotspot: the isotope hydrology framework of Corsica (western Mediterranean).

Science.gov (United States)

van Geldern, Robert; Kuhlemann, Joachim; Schiebel, Ralf; Taubald, Heinrich; Barth, Johannes A C

2014-06-01

The Mediterranean is regarded as a region of intense climate change. To better understand future climate change, this area has been the target of several palaeoclimate studies which also studied stable isotope proxies that are directly linked to the stable isotope composition of water, such as tree rings, tooth enamel or speleothems. For such work, it is also essential to establish an isotope hydrology framework of the region of interest. Surface waters from streams and lakes as well as groundwater from springs on the island of Corsica were sampled between 2003 and 2009 for their oxygen and hydrogen isotope compositions. Isotope values from lake waters were enriched in heavier isotopes and define a local evaporation line (LEL). On the other hand, stream and spring waters reflect the isotope composition of local precipitation in the catchment. The intersection of the LEL and the linear fit of the spring and stream waters reflect the mean isotope composition of the annual precipitation (δP) with values of-8.6(± 0.2) ‰ for δ(18)O and-58(± 2) ‰ for δ(2)H. This value is also a good indicator of the average isotope composition of the local groundwater in the island. Surface water samples reflect the altitude isotope effect with a value of-0.17(± 0.02) ‰ per 100 m elevation for oxygen isotopes. At Vizzavona Pass in central Corsica, water samples from two catchments within a lateral distance of only a few hundred metres showed unexpected but systematic differences in their stable isotope composition. At this specific location, the direction of exposure seems to be an important factor. The differences were likely caused by isotopic enrichment during recharge in warm weather conditions in south-exposed valley flanks compared to the opposite, north-exposed valley flanks.

Isotope separation system

International Nuclear Information System (INIS)

Lehmann, J.-C.

1975-01-01

A description is given of an isotope separation device comprising a system for converting into gaseous form a first and second isotope to be separated, a monochromatic excitation light source to excite the gaseous molecules of these two isotopes in a distinct manner, a first and second receiver to collect selectively the molecules of the first and second distinctly excited isotopes. The frequency FL of the excitation light is selected between a lower limit and a higher limit F2 + 1/2 LD, depending on the frequences F1 and F2 of two absorption lines near this first and second isotope. The difference DF between these two frequencies F1 and F2 is less than the Doppler width LD of each one of these lines and greater than the natural width LN of each of these two lines and also the width of line LR of the excitation light source. The probability that the molecules will be excited by this light depends on the direction of their displacement to a major and different extent for both isotopes. An ionising light source LI is set up to irradiate the seat of interaction between the excitation light and the gaseous molecules with an ionisation light able to ionise the excited molecules without ionising the molecules that are not excited. The receivers are able to collect selectively the ionised molecules. A sufficiently low gas pressure is selected for the distance between the place of interaction and the first receiver to be less than double the free mean travel of the molecules in the gas [fr

Canada's isotope crisis : what next?

International Nuclear Information System (INIS)

Nathwani, J.; Wallace, D.

2010-01-01

Canada urgently requires a rigorous debate on the strategic options for ensuring a robust, reliable, and affordable supply of radioactive isotopes. Should the debate be confined to how Canada can best develop the necessary technologies solely for our own use or should Canada abandon the idea of producing its own isotope supply and any future aspirations to serve the global market? Canada's Isotope Crisis focuses on the central policy question: do we dare to try to shape the future or do we retreat into silence because we are not prepared to make the necessary investments for the future well-being of Canadians? This volume showcases pointed essays and analysis from members of the academy and individuals who have made contributions to the development of medical isotopes and pioneered their use in medical practice. It also includes commentary from those involved in the production, manufacturing, processing, and distribution of isotopes. Canada's Isotope Crisis is a multi-disciplinary effort that addresses the global dimension of isotope supply and combines expert opinions on the present and past with knowledge of the relevant government agencies and the basis for their decisions at critical junctures.

Steroid isotopic standards for gas chromatography-combustion isotope ratio mass spectrometry (GCC-IRMS).

Science.gov (United States)

Zhang, Ying; Tobias, Herbert J; Brenna, J Thomas

2009-03-01

Carbon isotope ratio (CIR) analysis of urinary steroids using gas chromatography-combustion isotope ratio mass spectrometry (GCC-IRMS) is a recognized test to detect illicit doping with synthetic testosterone. There are currently no universally used steroid isotopic standards (SIS). We adapted a protocol to prepare isotopically uniform steroids for use as a calibrant in GCC-IRMS that can be analyzed under the same conditions as used for steroids extracted from urine. Two separate SIS containing a mixture of steroids were created and coded CU/USADA 33-1 and CU/USADA 34-1, containing acetates and native steroids, respectively. CU/USADA 33-1 contains 5alpha-androstan-3beta-ol acetate (5alpha-A-AC), 5alpha-androstan-3alpha-ol-17-one acetate (androsterone acetate, A-AC), 5beta-androstan-3alpha-ol-11, 17-dione acetate (11-ketoetiocholanolone acetate, 11k-AC) and 5alpha-cholestane (Cne). CU/USADA 34-1 contains 5beta-androstan-3alpha-ol-17-one (etiocholanolone, E), 5alpha-androstan-3alpha-ol-17-one (androsterone, A), and 5beta-pregnane-3alpha, 20alpha-diol (5betaP). Each mixture was prepared and dispensed into a set of about 100 ampoules using a protocol carefully designed to minimize isotopic fractionation and contamination. A natural gas reference material, NIST RM 8559, traceable to the international standard Vienna PeeDee Belemnite (VPDB) was used to calibrate the SIS. Absolute delta(13)C(VPDB) and Deltadelta(13)C(VPDB) values from randomly selected ampoules from both SIS indicate uniformity of steroid isotopic composition within measurement reproducibility, SD(delta(13)C)<0.2 per thousand. This procedure for creation of isotopic steroid mixtures results in consistent standards with isotope ratios traceable to the relevant international reference material.

The centenary of the discovery of isotopes

International Nuclear Information System (INIS)

Soulie, Edgar

2013-01-01

This article recalls works performed by different scientists (Marckwald and Keetman, Stromholm and Svedberg, Soddy, Thompson, Aston) which resulted in the observation and identification of the existence of isotopes. The author also recalls various works related to mechanisms of production of isotopes, the discovery of uranium fission and the principle of chain reaction. The author notably evokes French scientists involved in the development of mass spectroscopy and in the research and applications on isotopes within the CEA after the Second World War. A bibliography of article and books published by one of them, Etienne Roth, is provided. References deal with nuclear applications of chemical engineering (heavy water and its production, chemical processes in fission reactors, tritium extraction and enrichment), isotopic fractioning and physical-chemical processes, mass spectrometry and isotopic analysis, isotopic geochemistry (on 07;Earth, search for deuterium in moon rocks and their consequences), first dating and the Oklo phenomenon, radioactive dating, water and climate (isotopic hydrology, isotopes and hailstone formation, the atmosphere), and miscellaneous scientific fields (nuclear measurements and radioactivity, isotopic abundances and atomic weight, isotopic separation and use of steady isotopes)

Radiation absorbed dose estimate for rubidium-82 determined from in vivo measurements in human subjects

International Nuclear Information System (INIS)

Ryan, J. W.; Harper, P.V.; Stark, V.S.; Peterson, E.L.; Lathrop, K.A.

1986-01-01

Radiation absorbed doses from rubidium-82 injected intravenously were determined in two young men, aged 23 and 27, using a dynamic conjugate counting technique to provide data for the net organ integrated time-activity curves in five organs: kidneys, lungs, liver, heart, and testes. This technique utilized a tungsten collimated Anger camera and the accuracy was validated in a prestwood phantom. The data for each organ were compared with conjugate count rates of a reference Ge-68/Ga-68 standard which had been calibrated against the Rb-82 injected. The effects of attenuation in the body were eliminated. The MIRD method was used to calculate the organ self absorbed doses and the total organ absorbed doses. The mean total absorbed doses were as follows (mrads/mCi injected): kidneys 30.9, heart walls 7.5, lungs 6.0, liver 3.0, testes 2.0 (one subject only), red marrow 1.3, remainder of body 1.3 and, extrapolating to women, ovaries 1.2. This absorbed dose to the kidney is significantly less than the pessimistic estimate of 59.4 mrads/mCi, made assuming instantaneous uptake and complete extraction of activity with no excretion by the kidneys, which receive 20% of the cardiac output. Further, in a 68 year old man the renal self absorbed dose was approximately 40% less than the mean renal self absorbed dose of the younger men. This decrease is probably related to the decline in renal blood flow which occurs with advancing age but other factors may also contribute to the observed difference. 14 references, 4 figures, 2 tables

Therapeutic use of radioactive isotopes

CERN Document Server

Caroline Duc

2013-01-01

In December, researchers from ISOLDE-CERN, the Paul Scherrer Institute (PSI) and the Institut Laue-Langevin (ILL) published the results of an in vivo study which successfully proved the effectiveness of four terbium isotopes for diagnosing and treating cancerous tumours.   Four terbium isotopes suitable for clinical purposes. “ISOLDE is the only installation capable of supplying terbium isotopes of such purity and intensity in the case of three out of the four types used in this study,” explains Karl Johnson, a physicist at ISOLDE.  “Producing over a thousand different isotopes, our equipment offers the widest choice of isotopes in the world!” Initially intended for fundamental physics research, ISOLDE has diversified its activities over time to invest in various projects in the materials science, biochemistry and nuclear medicine fields. The proof-of-concept study has confirmed that the four terbium isotopes 149Tb, 152Tb, 155Tb produ...

Oak Ridge National Laboratory's isotope enrichment program

International Nuclear Information System (INIS)

Tracy, J.G.; Aaron, W.C.

1997-01-01

The Isotope Enrichment Program (IEP) at Oak Ridge National Laboratory (ORNL) is responsible for the production and distribution of ∼225 enriched stable isotopes from 50 multi-isotopic elements. In addition, ORNL distributes enriched actinide isotopes and provides extensive physical- and chemical-form processing of enriched isotopes to meet customer requirements. For more than 50 yr, ORNL has been a major provider of enriched isotopes and isotope-related services to research, medical, and industrial institutions throughout the world. Consolidation of the Isotope Distribution Office (IDO), the Isotope Research Materials Laboratory (IRML), and the stable isotope inventories in the Isotope Enrichment Facility (IEF) have improved operational efficiencies and customer services. Recent changes in the IEP have included adopting policies for long-term contracts, which offer program stability and pricing advantages for the customer, and prorated service charges, which greatly improve pricing to the small research users. The former U.S. Department of Energy (DOE) Loan Program has been converted to a lease program, which makes large-quantity or very expensive isotopes available for nondestructive research at a nominal cost. Current efforts are being pursued to improve and expand the isotope separation capabilities as well as the extensive chemical- and physical-form processing that now exists. The IEF's quality management system is ISO 9002 registered and accredited in the United States, Canada, and Europe

Isotope separation using tunable lasers

International Nuclear Information System (INIS)

Snavely, B.B.

1975-01-01

Various processes for laser isotope separation based upon the use of the spectroscopic isotope effect in atomic and molecular vapors are discussed. Emphasis is placed upon processes which are suitable for uranium enrichment. A demonstration process for the separation of uranium isotopes using selective photoionization is described. (U.S.)

High mass isotope separation process and arrangement

International Nuclear Information System (INIS)

Eerkens, J.W.

1978-01-01

An isotope separation arrangement for separating a preselected isotope from a mixture of chemically identical but isotopically different molecules by either photon-induced pure rovibrational or vibronic selective excitation of the molecules containing the atoms of the isotope to be separated from a lower to a higher energy state, and a chemical reaction of the higher energy state molecules with a chemically reactive agent to form a chemical compound containing primarily the atoms of isotope to be separated in a physicochemical state different from the physicochemical state of the mixture of chemically identical but isotopically different molecules. The chemical compound containing the atoms of the isotope to be separated may be subsequently processed to obtain the isotope

Transportation of medical isotopes

International Nuclear Information System (INIS)

Nielsen, D.L.

1997-01-01

A Draft Technical Information Document (HNF-1855) is being prepared to evaluate proposed interim tritium and medical isotope production at the Fast Flux Test Facility (FFTF). This assessment examines the potential health and safety impacts of transportation operations associated with the production of medical isotopes. Incident-free and accidental impacts are assessed using bounding source terms for the shipment of nonradiological target materials to the Hanford Site, the shipment of irradiated targets from the FFTF to the 325 Building, and the shipment of medical isotope products from the 325 Building to medical distributors. The health and safety consequences to workers and the public from the incident-free transportation of targets and isotope products would be within acceptable levels. For transportation accidents, risks to works and the public also would be within acceptable levels. This assessment is based on best information available at this time. As the medical isotope program matures, this analysis will be revised, if necessary, to support development of a final revision to the Technical Information Document

Transportation of medical isotopes

Energy Technology Data Exchange (ETDEWEB)

Nielsen, D.L.

1997-11-19

A Draft Technical Information Document (HNF-1855) is being prepared to evaluate proposed interim tritium and medical isotope production at the Fast Flux Test Facility (FFTF). This assessment examines the potential health and safety impacts of transportation operations associated with the production of medical isotopes. Incident-free and accidental impacts are assessed using bounding source terms for the shipment of nonradiological target materials to the Hanford Site, the shipment of irradiated targets from the FFTF to the 325 Building, and the shipment of medical isotope products from the 325 Building to medical distributors. The health and safety consequences to workers and the public from the incident-free transportation of targets and isotope products would be within acceptable levels. For transportation accidents, risks to works and the public also would be within acceptable levels. This assessment is based on best information available at this time. As the medical isotope program matures, this analysis will be revised, if necessary, to support development of a final revision to the Technical Information Document.

Development of Stable Isotope Technology

International Nuclear Information System (INIS)

Jeong, Do Young; Kim, Cheol Jung; Han, Jae Min

2009-03-01

KAERI has obtained an advanced technology with singular originality for laser stable isotope separation. Objectives for this project are to get production technology of Tl-203 stable isotope used for medical application and are to establish the foundation of the pilot system, while we are taking aim at 'Laser Isotope Separation Technology to make resistance to the nuclear proliferation'. And we will contribute to ensuring a nuclear transparency in the world society by taking part in a practical group of NSG and being collaboration with various international groups related to stable isotope separation technology

The Global Network of Isotopes in Rivers (GNIR): Integration of Stable Water Isotopes in Riverine Research and Management

International Nuclear Information System (INIS)

Halder, J.; Terzer, S.; Wassenaar, L.; Araguas, L.; Aggarwal, P.

2015-01-01

Rivers play a crucial role in the global water cycle as watershed-integrating hydrological conduits for returning terrestrial precipitation, runoff, surface and groundwater, as well as melting snow and ice back to the world’s oceans. The IAEA Global Network of Isotopes in Rivers (GNIR) is the coherent extension of the IAEA Global Network for Isotopes in Precipitation (GNIP) and aims to fill the informational data gaps between rainfall and river discharge. Whereas the GNIP has been surveying the stable hydrogen and oxygen isotopes, and tritium composition in precipitation, the objective of GNIR is to accumulate and disseminate riverine isotope data. We introduce the new global database of riverine water isotopes and evaluate its current long-term data holdings with the objective to improve the application of water isotopes and to inform water managers and researchers. An evaluation of current GNIR database holdings confirmed that seasonal variations of the stable water isotope composition in rivers are closely coupled to precipitation and snow-melt water run-off on a global scale. Rivers could be clustered on the basis of seasonal variations in their isotope composition and latitude. Results showed furthermore, that there were periodic phases within each of these groupings and additional modelling exercises allowed a priori prediction of the seasonal variability as well as the isotopic composition of stable water isotopes in rivers. This predictive capacity will help to improve existing and new sampling strategies, help to validate and interpret riverine isotope data, and identify important catchment processes. Hence, the IAEA promulgates and supports longterm hydrological isotope observation networks and the application of isotope studies complementary with conventional hydrological, water quality, and ecological studies. (author)

Isotopic Abundance and Chemical Purity Analysis of Stable Isotope Deuterium Labeled Sudan I

Directory of Open Access Journals (Sweden)

CAI Yin-ping;LEI Wen;ZHENG Bo;DU Xiao-ning

2014-02-01

Full Text Available It is important that to analysis of the isotopic abundance and chemical purity of Sudan I-D5, which is the internal standard of isotope dilution mass spectrometry. The isotopic abundance of Sudan I-D5 is detected by “mass cluster” classification method and LC-MS. The repeatability and reproducibility experiments were carried out by using different mass spectrometers and different operators. The RSD was less than 0.1%, so the repeatability and reproducibility were satisfactory. The accuracy and precision of the isotopic abundance analysis method was good with the results of F test and t test. The high performance liquid chromatography (HPLC had been used for detecting the chemical purity of Sudan I-D5 as external standard method.

2. Workshop 'Isotopes in Nature'. 1

International Nuclear Information System (INIS)

1979-11-01

The workshop was aimed at discussing in detail the following problems: (1) distribution of stable and radioactive isotopes in nature, (2) theoretical and experimental studies of isotopic effects in natural processes, (3) problems of sample preparation and sample measurement in determining the relative abundance of stable isotopes or radioactive isotopes in nature, (4) age estimations of samples from different areas of the geosphere, (5) contributions to the specification of global and regional substance cycles in nature with the aid of isotopic and geochemical studies. 75 summaries are included

Application of TIMS in isotope correlations for determining the isotope ratios of plutonium

International Nuclear Information System (INIS)

Alamelu, D.; Aggarwal, S.K.

2003-01-01

Thermal ionisation mass spectrometry (TIMS) is a well-recognized technique for determining the isotopic composition of Pu in irradiated nuclear fuel samples. Other mass spectrometric methods such as ICPMS, SIMS can also be employed for the isotopic analysis of Pu. In the event of non-availability of a mass spectrometer, other techniques such as gamma spectrometry and alpha spectrometry can also be used. They have a limited applicability since data on all the Pu isotopes cannot be obtained

Isotopes in environmental research

International Nuclear Information System (INIS)

Bowen, G.; Rozanski, K.; Vose, P.

1990-01-01

Radioactive and stable isotopes have long been considered a very efficient tool for studying physical and biological aspects of how the global ecosystem functions. Their applications in environmental research are numerous, embracing research at all levels. This article looks at only a few of the approaches to environmental problems that involve the use of isotopes. Special attention is given to studies of the Amazon Basin. Environmental isotopes are very efficient tools in water cycle studies. Tritium, a radioactive tracer, is especially useful in studying dynamics of water movement in different compartments of the hydrosphere, both on the local and global scales. Heavy stable isotopes of hydrogen and oxygen (deuterium and oxygen-18) provide information about steady-state characteristics of the water cycle. Isotope methods, some relatively new, have a major role in site-specific studies. Some indicative examples include: Studying turnover of organic matter. Changes in the carbon-13/carbon-12 isotopic ratio of organic matter were used to determine the respective contributions of organic carbon derived from forest and pasture. Studying biological nitrogen fixation. One of the ways nitrogen levels in soil can be maintained for productivity is by biological nitrogen fixation. Studying nitrogen availability and losses. The experimental use of nitrogen-15 is invaluable for defining losses of soil nitrogen to the atmosphere and to groundwater. Studies can similarly be done with stable and radioactive sulphur isotopes. This article indicates some potential uses of isotopes in environmental research. While the major problem of global climate change has not been specifically addressed here, the clearing of the Amazon forest, one focus of the IAEA's environmental programme, may have serious consequences for the global climate. These include substantial reduction of the amount of latent heat transported to the regions outside the tropics and acceleration of the greenhouse

Utilizing Stable Isotopes and Isotopic Anomalies to Study Early Solar System Formation Processes

Science.gov (United States)

Simon, Justin

2017-01-01

Chondritic meteorites contain a diversity of particle components, i.e., chondrules and calcium-, aluminum-rich refractory inclusions (CAIs), that have survived since the formation of the Solar System. The chemical and isotopic compositions of these materials provide a record of the conditions present in the protoplanetary disk where they formed and can aid our understanding of the processes and reservoirs in which solids formed in the solar nebula, an important step leading to the accretion of planetesimals. Isotopic anomalies associated with nucleosynthetic processes are observed in these discrete materials, and can be compared to astronomical observations and astrophysical formation models of stars and more recently proplyds. The existence and size of these isotopic anomalies are typically thought to reflect a significant state of isotopic heterogeneity in the earliest Solar System, likely left over from molecular cloud heterogeneities on the grain scale, but some could also be due to late stellar injection. The homogenization of these isotopic anomalies towards planetary values can be used to track the efficiency and timescales of disk wide mixing,

Tin isotope fractionation during magmatic processes and the isotope composition of the bulk silicate Earth

Science.gov (United States)

Wang, Xueying; Amet, Quentin; Fitoussi, Caroline; Bourdon, Bernard

2018-05-01

Tin is a moderately volatile element whose isotope composition can be used to investigate Earth and planet differentiation and the early history of the Solar System. Although the Sn stable isotope composition of several geological and archaeological samples has been reported, there is currently scarce information about the effect of igneous processes on Sn isotopes. In this study, high-precision Sn isotope measurements of peridotites and basalts were obtained by MC-ICP-MS with a double-spike technique. The basalt samples display small variations in δ124/116Sn ranging from -0.01 ± 0.11 to 0.27 ± 0.11‰ (2 s.d.) relative to NIST SRM 3161a standard solution, while peridotites have more dispersed and more negative δ124Sn values ranging from -1.04 ± 0.11 to -0.07 ± 0.11‰ (2 s.d.). Overall, basalts are enriched in heavy Sn isotopes relative to peridotites. In addition, δ124Sn in peridotites become more negative with increasing degrees of melt depletion. These results can be explained by different partitioning behavior of Sn4+ and Sn2+ during partial melting. Sn4+ is overall more incompatible than Sn2+ during partial melting, resulting in Sn4+-rich silicate melt and Sn2+-rich residue. As Sn4+ has been shown experimentally to be enriched in heavy isotopes relative to Sn2+, the effect of melting is to enrich residual peridotites in relatively more compatible Sn2+, which results in isotopically lighter peridotites and isotopically heavier mantle-derived melts. This picture can be disturbed partly by the effect of refertilization. Similarly, the presence of enriched components such as recycled oceanic crust or sediments could explain part of the variations in Sn isotopes in oceanic basalts. The most primitive peridotite analyzed in this study was used for estimating the Sn isotope composition of the BSE, with δ124Sn = -0.08 ± 0.11‰ (2 s.d.) relative to the Sn NIST SRM 3161a standard solution. Altogether, this suggests that Sn isotopes may be a powerful probe of

Calcium stable isotope geochemistry

Energy Technology Data Exchange (ETDEWEB)

Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

2016-08-01

This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

Calcium stable isotope geochemistry

International Nuclear Information System (INIS)

Gausonne, Nikolaus; Schmitt, Anne-Desiree; Heuser, Alexander; Wombacher, Frank; Dietzel, Martin; Tipper, Edward; Schiller, Martin

2016-01-01

This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

Isotope effects: definitions and consequences for pharmacologic studies

International Nuclear Information System (INIS)

Van Langenhove, A.

1986-01-01

The use of stable isotope-labeled compounds for pharmacologic studies requires careful consideration of the nature of the stable isotope label (2H, 13C, 15N, 18O) and its position of incorporation in the molecule. When deuterium is used, improper positioning can lead to significant primary isotope effects. Primary isotope effects occur when the breaking of the bond to the heavy isotope is the rate-limiting step in a reaction (or metabolic transformation). A reaction will proceed slower for the molecule with the heavy isotope label because of the mass difference between the light and the heavy isotope. In addition to these primary isotope effects, smaller but nevertheless important secondary isotope effects, physicochemical isotope effects, active hydrogen/deuterium exchange, or isotope effects associated with either the enzyme-catalyzed biotransformation or the mass spectrometric ionization and fragmentation can be operative. In mechanistic studies, isotope effects are used to their advantage; however, in pharmacokinetic studies, the occurrence of isotope effects can lead to grossly misleading biologic and analytic results: the metabolism of the drug will differ when in vivo isotope effects are operative, and isotope effects occurring during the analysis procedure will obscure the true metabolic profile of the drug

Isotopic meteoric line for Colombia

International Nuclear Information System (INIS)

Rodriguez N, Cesar O

2004-01-01

Isotope analyses from representative rainfall samples taken from different areas in Colombia were processed to yield the meteoric line. Stable isotope composition in precipitation reflects the effects of temperature, altitude and of the continental site, being affected by different sources of atmospheric humidity over the Colombian territory. There is a seasonal variation in isotopic composition of precipitation with grater σ deviation during the rainy season and lower values in the dry season. In coastal areas the variation is smaller and is more pronounced than at continental stations. Correlation between altitude and isotope content led to equations, which indicate, on a regional level, a change in isotopic composition with altitude, of about 0.5 σ units per 200 m, for O 18 and 4 σ units per 200 m for H 2 . Such equations may be used to identify the original altitude of precipitation water, in hydrological surface and groundwater studies. Meteoric line and the concepts derived from the resulting equations presented in this paper may be applied to the interpretation of isotope analysis in future hydrological studies, particularly in areas without available data

Isotope research materials

International Nuclear Information System (INIS)

Anon.

1977-01-01

Preparation of research isotope materials is described. Topics covered include: separation of tritium from aqueous effluents by bipolar electrolysis; stable isotope targets and research materials; radioisotope targets and research materials; preparation of an 241 Am metallurgical specimen; reactor dosimeters; ceramic and cermet development; fission-fragment-generating targets of 235 UO 2 ; and wire dosimeters for Westinghouse--Bettis

Finite mixture models for the computation of isotope ratios in mixed isotopic samples

Science.gov (United States)

Koffler, Daniel; Laaha, Gregor; Leisch, Friedrich; Kappel, Stefanie; Prohaska, Thomas

2013-04-01

Finite mixture models have been used for more than 100 years, but have seen a real boost in popularity over the last two decades due to the tremendous increase in available computing power. The areas of application of mixture models range from biology and medicine to physics, economics and marketing. These models can be applied to data where observations originate from various groups and where group affiliations are not known, as is the case for multiple isotope ratios present in mixed isotopic samples. Recently, the potential of finite mixture models for the computation of 235U/238U isotope ratios from transient signals measured in individual (sub-)µm-sized particles by laser ablation - multi-collector - inductively coupled plasma mass spectrometry (LA-MC-ICPMS) was demonstrated by Kappel et al. [1]. The particles, which were deposited on the same substrate, were certified with respect to their isotopic compositions. Here, we focus on the statistical model and its application to isotope data in ecogeochemistry. Commonly applied evaluation approaches for mixed isotopic samples are time-consuming and are dependent on the judgement of the analyst. Thus, isotopic compositions may be overlooked due to the presence of more dominant constituents. Evaluation using finite mixture models can be accomplished unsupervised and automatically. The models try to fit several linear models (regression lines) to subgroups of data taking the respective slope as estimation for the isotope ratio. The finite mixture models are parameterised by: • The number of different ratios. • Number of points belonging to each ratio-group. • The ratios (i.e. slopes) of each group. Fitting of the parameters is done by maximising the log-likelihood function using an iterative expectation-maximisation (EM) algorithm. In each iteration step, groups of size smaller than a control parameter are dropped; thereby the number of different ratios is determined. The analyst only influences some control

Mass fractionation processes of transition metal isotopes

Science.gov (United States)

Zhu, X. K.; Guo, Y.; Williams, R. J. P.; O'Nions, R. K.; Matthews, A.; Belshaw, N. S.; Canters, G. W.; de Waal, E. C.; Weser, U.; Burgess, B. K.; Salvato, B.

2002-06-01

Recent advances in mass spectrometry make it possible to utilise isotope variations of transition metals to address some important issues in solar system and biological sciences. Realisation of the potential offered by these new isotope systems however requires an adequate understanding of the factors controlling their isotope fractionation. Here we show the results of a broadly based study on copper and iron isotope fractionation during various inorganic and biological processes. These results demonstrate that: (1) naturally occurring inorganic processes can fractionate Fe isotope to a detectable level even at temperature ˜1000°C, which challenges the previous view that Fe isotope variations in natural system are unique biosignatures; (2) multiple-step equilibrium processes at low temperatures may cause large mass fractionation of transition metal isotopes even when the fractionation per single step is small; (3) oxidation-reduction is an importation controlling factor of isotope fractionation of transition metal elements with multiple valences, which opens a wide range of applications of these new isotope systems, ranging from metal-silicate fractionation in the solar system to uptake pathways of these elements in biological systems; (4) organisms incorporate lighter isotopes of transition metals preferentially, and transition metal isotope fractionation occurs stepwise along their pathways within biological systems during their uptake.

Hyperfine structure and isotope shift of the neutron-rich barium isotopes 139-146Ba and 148Ba

International Nuclear Information System (INIS)

Wendt, K.; Ahmad, S.A.; Klempt, W.; Neugart, R.; Otten, E.W.

1988-01-01

The hyperfine structure and isotope shift in the 6s 2 S 1/2 -6p 2 P 3/2 line of Ba II (455.4 nm) have been measured by collinear fast-beam laser spectroscopy for the neutron-rich isotopes 139-146 Ba and 148 Ba. Nuclear moments and mean square charge radii of these isotopes have been recalculated. The isotope shift of the isotope 148 Ba (T 1/2 = 0.64 s) could be studied for the first time, yielding δ 2 > 138,148 = 1.245(3) fm 2 . (orig.)

Copper isotope fractionation by desert shrubs

International Nuclear Information System (INIS)

Navarrete, Jesica U.; Viveros, Marian; Ellzey, Joanne T.; Borrok, David M.

2011-01-01

Copper has two naturally occurring stable isotopes of masses 63 and 65 which can undergo mass dependent fractionation during various biotic and abiotic chemical reactions. These interactions and their resulting Cu isotope fractionations can be used to determine the mechanisms involved in the cycling of Cu in natural systems. In this study, Cu isotope changes were investigated at the organismal level in the metal-accumulating desert plant, Prosopis pubescens. Initial results suggest that the lighter Cu isotope was preferentially incorporated into the leaves of the plant, which may suggest that Cu was actively transported via intracellular proteins. The roots and stems show a smaller degree of Cu isotope fractionation and the direction and magnitude of the fractionations was dependent upon the levels of Cu exposure. Based on this and previous work with bacteria and yeast, a trend is emerging that suggests the lighter Cu isotope is preferentially incorporated into biological components, while the heavier Cu isotope tends to become enriched in aqueous solutions. In bacteria, plants and animals, intracellular Cu concentrations are strictly regulated via dozens of enzymes that can bind, transport, and store Cu. Many of these enzymes reduce Cu(II) to Cu(I). These initial results seem to fit into a broader picture of Cu isotope cycling in natural systems where oxidation/reduction reactions are fundamental in controlling the distributions of Cu isotopes.

Development of isotope hydrology technology in China

International Nuclear Information System (INIS)

Li Zhangsu

1988-01-01

The development of isotope hydrology technology in China is described. The isotope technology provides an independent approach for solving hydrological problems. Isotope hydrology is applied in three ways: the use of change in environmental isotopic composition of water (especially used in water resources exploitation), the use of artificial radioactive tracers and the use of redioisotope instruments. Many important achievements have been obtained in application of isotopic hydrology technology. For the sake of promoting rapid development of isotope hydrology the topics on management, technology and others are commented

Chemical separation of boron isotopes

Energy Technology Data Exchange (ETDEWEB)

Palko, A.A.

1978-06-01

This is the final report of the research performed at ORNL on the chemical fractionation of boron isotopes between BF/sub 3/ gas and the liquid molecular addition compounds of BF/sub 3/. Thirty compounds were studied, ten of them in detail. Graphs and equations are given for variation of isotopic equilibrium constant, vapor pressure, and BF/sub 3/ solubility as a function of temperature. Rate of isotopic exchange and melting points were determined. Several of the compounds are likely candidates for use in a gas-liquid countercurrent exchange system for large-scale separation of boron isotopes. 23 figs, 53 tables, 39 references.

Melatonin labeled with hydrogen isotopes

International Nuclear Information System (INIS)

Dmitrevskaya, L.I.; Smushkevich, Yu.I.; Kurkovskaya, L.N.; Ponomarenko, N.K.; Suvorov, N.N.

1989-01-01

A study has been made of isotope exchange between melatonin and deuterium (D 2 O) or tritium (HTO) oxide under different conditions. The ease of isotope exchange for the indole ring hydrogens of melatonin in an acidic medium decreases over the series H 4 > H 2 H 6 >> H 7 , enabling the authors to process a route for production of melatonin labeled with hydrogen isotopes at positions 4,6, and 2 of the indole ring. A method has been suggested for producing melatonin labeled with hydrogen isotopes at position 2 by desulfurization of 2-(2,4-dinitro-phenylsulfenyl)melatonin at Ni(Re) (D)

Melatonin labelled by hydrogen isotopes

International Nuclear Information System (INIS)

Dmitrevskaya, L.I.; Smushkevich, Yu.I.; Kurkovskaya, L.N.; Ponomarenko, N.K.; Suvorov, N.N.

1988-01-01

Isotope exchange of melatonin with deuterium (D 2 O) and tritium (HTO) oxides under different conditions is studied. Simplicity of isotope exchange of hydrogens of the indole ring of melatonin in the acidic medium decreases in series H 4 >H 2 >H 6 >>H 7 , that permits to suggest the way of melatonin preparation labelled by hydrogen isotopes in positions 4,6 and 2 of the indole ring. The way of melatonin preparation labelled by hydrogen isotopes in position 2 according to the reaction of desulfation 2-(2,4-dinitrophenylsulphenyl) melatonin at catalyst Ni(Re)(D) is suggested

Chemical separation of boron isotopes

International Nuclear Information System (INIS)

Palko, A.A.

1978-06-01

This is the final report of the research performed at ORNL on the chemical fractionation of boron isotopes between BF 3 gas and the liquid molecular addition compounds of BF 3 . Thirty compounds were studied, ten of them in detail. Graphs and equations are given for variation of isotopic equilibrium constant, vapor pressure, and BF 3 solubility as a function of temperature. Rate of isotopic exchange and melting points were determined. Several of the compounds are likely candidates for use in a gas-liquid countercurrent exchange system for large-scale separation of boron isotopes. 23 figs, 53 tables, 39 references

Method for enriching and separating heavy hydrogen isotopes from substance streams containing such isotopes by means of isotope exchange

International Nuclear Information System (INIS)

Knochel, A.; Eggers, I.; Klatte, B.; Wilken, R. D.

1985-01-01

A process for enriching and separating heavy hydrogen isotopes having a heavy hydrogen cation (deuterium and/or tritium) from substance streams containing them, wherein the respectively present hydrogen isotopes are exchanged in chemical equilibria. A protic, acid solution containing deuterium and/or tritium is brought into contact with a value material from the group of open-chained polyethers or aminopolyethers, macro-monocyclic or macro-polycyclic polyethers, macro-monocyclic or macro-polycyclic amino polyethers, and mixtures of these values, in their free or proton salt form to form a reaction product of the heavy hydrogen cation with the value or value salt and bring about enrichment of deuterium and/or tritium in the reaction product. The reaction product containing the value or value salt is separated from the solution. The separated reaction product is treated to release the hydrogen isotope(s) to be enriched in the form of deuterium oxide (HDO) and/or tritium oxide (HTO) by regenerating the value or its salt, respectively. The regenerated value is returned for reuse

Isotopic composition of cosmic ray nuclei

International Nuclear Information System (INIS)

Enge, W.

1976-01-01

A review will be given on the role of cosmic ray isotopes as tracers of the astrophysical nucleo-synthesis. The products of every nuclear burning chain are first of all isotopes and not elements. Thus, it is the study of the isotopes rather than that of the elements that responds to the questions on these nucleo-synthetic reactions. The problems concerning the solar system isotopic abundances and the cosmic ray isotopic abundances as well as a comparison between both will be presented. Furthermore the present stage of the experimental techniques and the latest results will be discussed. (orig.) [de

Isotopically labelled pyrimidines and purines

International Nuclear Information System (INIS)

Balaban, A.T.; Bally, I.

1987-01-01

Among the three diazines, pyrimidine is by far the most important one because its derivatives uracil, thymine and cytosine are constituents of the ubiquitous deoxynucleic acids (DNA) and ribonucleic acids (RNA). Other derivatives of pyrimidine without condensed rings include barbiturates, alloxan, orotic acid and thiamine or vitamin B 1 . From the polycyclic derivatives of pyrimidine such as pteridine, alloxazine, and purine, the latter, through its derivatives adenine and guanine complete the list of bases which occur in DNA and RNA: in addition, other purine derivatives such as hypoxanthine, xanthine, theobromine, theophylline, caffeine and uric acid are important natural products with biological activity. The paper presents methods for preparing isotopically labeled pyrimidines as well as purine derivatives. For convenience, the authors describe separately carbon-labeled with radioisotopes 11 C (T 1/2 = 20.3 min) and 14 C (T 1/2 = 5736 years) or the stable isotope 13 C (natural abundance 1.1%) and then hydrogen-labeled systems with the radioisotope 3 H ≡ T (T 1/2 = 12.346 years) or with the stable isotope 2 H ≡ D (natural abundance 0.015%). We do not separate stable from radioactive isotopes because the synthetic methods are identical for the same element; however, the introduction of hydrogen isotopes into organic molecules is often performed by reactions such as isotope exchange which cannot take place in the case of carbon isotopes

Isotope-based quantum information

International Nuclear Information System (INIS)

Plekhanov, Vladimir G.

2012-01-01

The present book provides to the main ideas and techniques of the rapid progressing field of quantum information and quantum computation using isotope - mixed materials. It starts with an introduction to the isotope physics and then describes of the isotope - based quantum information and quantum computation. The ability to manipulate and control electron and/or nucleus spin in semiconductor devices provides a new route to expand the capabilities of inorganic semiconductor-based electronics and to design innovative devices with potential application in quantum computing. One of the major challenges towards these objectives is to develop semiconductor-based systems and architectures in which the spatial distribution of spins and their properties can be controlled. For instance, to eliminate electron spin decoherence resulting from hyperfine interaction due to nuclear spin background, isotopically controlled devices are needed (i.e., nuclear spin-depleted). In other emerging concepts, the control of the spatial distribution of isotopes with nuclear spins is a prerequisite to implement the quantum bits (or qbits). Therefore, stable semiconductor isotopes are important elements in the development of solid-state quantum information. There are not only different algorithms of quantum computation discussed but also the different models of quantum computers are presented. With numerous illustrations this small book is of great interest for undergraduate students taking courses in mesoscopic physics or nanoelectronics as well as quantum information, and academic and industrial researches working in this field.

Isotopic coherence of refractory inclusions from CV and CK meteorites: Evidence from multiple isotope systems

Science.gov (United States)

Shollenberger, Quinn R.; Borg, Lars E.; Render, Jan; Ebert, Samuel; Bischoff, Addi; Russell, Sara S.; Brennecka, Gregory A.

2018-05-01

Calcium-aluminum-rich inclusions (CAIs) are the oldest dated materials in the Solar System and numerous previous studies have revealed nucleosynthetic anomalies relative to terrestrial rock standards in many isotopic systems. However, most of the isotopic data from CAIs has been limited to the Allende meteorite and a handful of other CV3 chondrites. To better constrain the isotopic composition of the CAI-forming region, we report the first Sr, Mo, Ba, Nd, and Sm isotopic compositions of two CAIs hosted in the CK3 desert meteorites NWA 4964 and NWA 6254 along with two CAIs from the CV3 desert meteorites NWA 6619 and NWA 6991. After consideration of neutron capture processes and the effects of hot-desert weathering, the Sr, Mo, Ba, Nd, and Sm stable isotopic compositions of the samples show clearly resolvable nucleosynthetic anomalies that are in agreement with previous results from Allende and other CV meteorites. The extent of neutron capture, as manifested by shifts in the observed 149Sm-150Sm isotopic composition of the CAIs is used to estimate the neutron fluence experienced by some of these samples and ranges from 8.40 × 1013 to 2.11 × 1015 n/cm2. Overall, regardless of CAI type or host meteorite, CAIs from CV and CK chondrites have similar nucleosynthetic anomalies within analytical uncertainty. We suggest the region that CV and CK CAIs formed was largely uniform with respect to Sr, Mo, Ba, Nd, and Sm isotopes when CAIs condensed and that CAIs hosted in CV and CK meteorites are derived from the same isotopic reservoir.

Combining Solvent Isotope Effects with Substrate Isotope Effects in Mechanistic Studies of Alcohol and Amine Oxidation by Enzymes*

Science.gov (United States)

Fitzpatrick, Paul F.

2014-01-01

Oxidation of alcohols and amines is catalyzed by multiple families of flavin-and pyridine nucleotide-dependent enzymes. Measurement of solvent isotope effects provides a unique mechanistic probe of the timing of the cleavage of the OH and NH bonds, necessary information for a complete description of the catalytic mechanism. The inherent ambiguities in interpretation of solvent isotope effects can be significantly decreased if isotope effects arising from isotopically labeled substrates are measured in combination with solvent isotope effects. The application of combined solvent and substrate (mainly deuterium) isotope effects to multiple enzymes is described here to illustrate the range of mechanistic insights that such an approach can provide. PMID:25448013

Isotope separation process

International Nuclear Information System (INIS)

Lyon, R.K.

1979-01-01

A method is described for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption after which more of the excited molecules than nonexcited molecules are converted to a chemically different form which may be separated by means known in the art. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium

Isotope shifting capacity of rock

International Nuclear Information System (INIS)

Blattner, P.; Department of Scientific and Industrial Research, Lower Hutt

1980-01-01

Any oxygen isotope shifted rock volume exactly defines a past throughput of water. An expression is derived that relates the throughput of an open system to the isotope shift of reservoir rock and present-day output. The small isotope shift of Ngawha reservoir rock and the small, high delta oxygen-18 output are best accounted for by a magmatic water source

Radiation gradient isotope separator

International Nuclear Information System (INIS)

Hughes, J.L.

1980-01-01

A system is described for transporting, separating and storing charged particles, charged antiparticles and fully or partially ionized isotopes of any element comprising a laser beam generator, laser beam intensity profiler, a laser beam variable intensity attenuator, and means for injecting charged particles, charged antiparticles and ionized isotopes into the beam and extracting them from the system as required. The invention is particularly useful for channelling electrons and ions used for fuel pellet compression in inertial fusion systems, for separating the isotopes of elements and for the confinement of charged antiparticles and particle/antiparticle plasmas

Determination of zinc stable isotopes in biological materials using isotope dilution inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Patterson, K.Y.; Veillon, Claude

1992-01-01

A method is described for using isotope dilution to determine both the amount of natural zinc and enriched isotopes of zinc in biological samples. Isotope dilution inductively coupled plasma mass spectrometry offers a way to quantify not only the natural zinc found in a sample but also the enriched isotope tracers of zinc. Accurate values for the enriched isotopes and natural zinc are obtained by adjusting the mass count rate data for measurable instrumental biases. Analytical interferences from the matrix are avoided by extracting the zinc from the sample matrix using diethylammonium diethyldithiocarbamate. The extraction technique separates the zinc from elements which form interfering molecular ions at the same nominal masses as the zinc isotopes. Accuracy of the method is verified using standard reference materials. The detection limit is 0.06 μg Zn per sample. Precision of the abundance ratios range from 0.3-0.8%. R.S.D. for natural zinc concentrations is about 200-600 μg g -1 . The accuracy and precision of the measurements make it possible to follow enriched isotopic tracers of zinc in biological samples in metabolic tracer studies. (author). 19 refs.; 1 fig., 4 tabs

Stable isotope analysis of Dacryoconarid carbonate microfossils: a new tool for Devonian oxygen and carbon isotope stratigraphy.

Science.gov (United States)

Frappier, Amy Benoit; Lindemann, Richard H; Frappier, Brian R

2015-04-30

Dacryoconarids are extinct marine zooplankton known from abundant, globally distributed calcite microfossils in the Devonian, but their shell stable isotope composition has not been previously explored. Devonian stable isotope stratigraphy is currently limited to less common invertebrates or bulk rock analyses of uncertain provenance. As with Cenozoic planktonic foraminifera, isotopic analysis of dacryoconarid shells could facilitate higher-resolution, geographically widespread stable isotope records of paleoenvironmental change, including marine hypoxia events, climate changes, and biocrises. We explored the use of Dacryoconarid isotope stratigraphy as a viable method in interpreting paleoenvironments. We applied an established method for determining stable isotope ratios (δ(13) C, δ(18) O values) of small carbonate microfossils to very well-preserved dacryoconarid shells. We analyzed individual calcite shells representing five common genera using a Kiel carbonate device coupled to a MAT 253 isotope ratio mass spectrometer. Calcite shell δ(13) C and δ(18) O values were compared by taxonomic group, rock unit, and locality. Single dacryoconarid calcite shells are suitable for stable isotope analysis using a Kiel-IRMS setup. The dacryoconarid shell δ(13) C values (-4.7 to 2.3‰) and δ(18) O values (-10.3 to -4.8‰) were consistent across taxa, independent of shell size or part, but varied systematically through time. Lower fossil δ(18) O values were associated with warmer water temperature and more variable δ(13) C values were associated with major bioevents. Dacryoconarid δ(13) C and δ(18) O values differed from bulk rock carbonate values. Dacryoconarid individual microfossil δ(13) C and δ(18) O values are highly sensitive to paleoenvironmental changes, thus providing a promising avenue for stable isotope chemostratigraphy to better resolve regional to global paleoceanographic changes throughout the upper Silurian to the upper Devonian. Our results

Sulfur and selenium isotope separation by distillation

International Nuclear Information System (INIS)

Mills, T. R.; McInteer, B. B.; Montoya, J. G.

1988-01-01

Sulfur and selenium isotopes are used for labeled compounds and as precursors for radioisotope production; however, both limited availability and high costs are problems. A new method is needed for large-scale separation of these isotopes. Experimental distillation columns were used to measure isotopic separations for sulfur and selenium compounds. The maximum total isotope separation of 32 S vs. 34 S were 1.127 for H 2 S, 1.048 for COS, 0.838 for SF 4 , and 1.058 for CH 3 SH. Relative volatilities of 32 S vs. 34 S are 1.0006 for COS and 0.9976 for SF 4 . There is a reverse isotope effect for carbon in COS. No isotopic separation was observed for dimethyl selenide. The lower mass selenium isotopes in H 2 Se are more volatile. Distillation is a promising method for separating sulfur isotopes on a production scale. Existing distillation technology produced separated isotopes with an effect similar to that found for sulfur in SF 4 . 8 refs., 2 tabs

Sulfur and selenium isotope separation by distillation

International Nuclear Information System (INIS)

Mills, T.R.; McInteer, B.B.; Montoya, J.G.

1989-01-01

Sulfur and selenium isotopes are used for labeled compounds and as precursors for radioisotope production; however, both limited availability and high costs are problems. A new method is needed for large-scale separation of theses isotopes. Experimental distillation columns were used to measure isotopic separations for sulfur and selenium compounds. The maximum total isotope separations of 32 S vs. 34 S were 1.127 for H 2 S, 1.048 for COS, 0.838 for SF 4 , and 1.058 for CH 3 SH. Relative volatilities of 32 S and 34 S are 1.0006 for COS and 0.9976 for SF 4 . There is a reverse isotope effect for carbon in COS. No isotopic separation was observed for dimethyl selenide. The lower mass selenium isotopes in H 2 Se are more volatile. Distillation is a promising method for separating sulfur isotopes on a production scale. Existing distillation technology produces separated isotopes with an effect similar to that found for sulfur in SF 4 . (author). 8 refs.; 2 tabs

Isotope products manufacture in Russia and its prospects

International Nuclear Information System (INIS)

Malyshev, S.V.; Okhotina, I.A.; Kalelin, E.A.; Krasnov, N.N.; Kuzin, V.V.; Malykh, J.A.; Makarovsky, S.B.

1997-01-01

At the present stage of the world economy development, stable and radioactive isotopes,preparations and products on their base are widely used in many fields of the national economy, medicine and scientific researches. The Russian Federation is one of the largest worldwide producers of a variety of nuclide products on the base of more than 350 isotopes, as follows: stable isotopes reactor, cyclotron, fission product radioactive isotopes, ion-radiation sources compounds, labelled with stable and radioactive isotopes, radionuclide short-lived isotope generators, radiopharmaceuticals, radionuclide light and heat sources; luminous paints on base of isotopes. The Russian Ministry for Atomic Energy coordinates activity for development and organization of manufacture and isotope products supply in Russia as well as for export. Within many years of isotope industry development, there have appeared some manufacturing centres in Russia, dealing with a variety of isotope products. The report presents the production potentialities of these centres and also an outlook on isotope production development in Russia in the next years

Stable isotopes labelled compounds

International Nuclear Information System (INIS)

1982-09-01

The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

Separation of uranium isotopes

International Nuclear Information System (INIS)

Porter, J.T.

1980-01-01

Methods and apparatus are disclosed for separation of uranium isotopes by selective isotopic excitation of photochemically reactive uranyl salt source material at cryogenic temperatures, followed by chemical separation of selectively photochemically reduced U+4 thereby produced from remaining uranyl source material

isotopic characteristics of aquifers in sinai

International Nuclear Information System (INIS)

Al-Gamal, S.A.

2004-01-01

the environmental isotopes data (expressed as δ 2 d and δ 18 O) of different aquifers in sinai were treated using correlation and regression techniques. whereas, rain water isotopic data were treated using empirical orthogonal functions (EOF) techniques. environmental isotopes for different aquifers expressed in terms of O-18 and H-2, were taken to represent the isotopic characteristics. regression equations using the highly correlated variables of δ 2 d and δ 18 O were constructed for each aquifer. the latitudinal variations (of rainwater in sinai and selected climatic stations east mediterranean ) versus rainwater isotopic compositions were analyzed using the normalized variables. it was found that the latitudinal variations of the rainwater isotopic compositions ( δ 2 D, δ 18 O), vapor pressure, and surface temperature occurred in parallel and decreased with latitude. in the east mediterranean, empirical linear relationship between altitude and δ 2 D has indicted that the rate of change of δ 2 D with height is comparable with the dry lapse rate in the atmosphere.The obtained regression equations of environmental isotopes data have impacted on different slopes and different constants expressing the non-homogeneity in the isotopic composition of rainwater recharging the aquifers of sinai , due to the presence of different air masses

Isotope separation by photoselective dissociative electron

International Nuclear Information System (INIS)

Stevens, C.G.

1978-01-01

A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule is described. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, 235 UF 6 is separated from a UF 6 mixture by selective excitation followed by dissociative electron capture into 235 UF 5 - and F

A novel methodology to investigate isotopic biosignatures

Science.gov (United States)

Horner, T. J.; Lee, R. B. Y.; Henderson, G. M.; Rickaby, R. E. M.

2012-04-01

An enduring goal of trace metal isotopic studies of Earth History is to find isotopic 'fingerprints' of life or of life's individual physiochemical processes. Generally, such signatures are sought by relating an isotopic effect observed in controlled laboratory conditions or a well-characterized environment to a more complex system or the geological record. However, such an approach is ultimately limited because life exerts numerous isotopic fractionations on any one element so it is hard to dissect the resultant net fractionation into its individual components. Further, different organisms, often with the same apparent cellular function, can express different isotopic fractionation factors. We have used a novel method to investigate the isotopic fractionation associated with a single physiological process-enzyme specific isotopic fractionation. We selected Cd isotopes since only one biological use of Cd is known, CdCA (a Cd/Zn carbonic anhydrase from the coastal diatom T. Weissflogii). Thus, our investigation can also inform the long standing mystery as to why this generally toxic element appears to have a nutrient-like dissolved isotopic and concentration profile in the oceans. We used the pET-15b plasmid to insert the CdCA gene into the E. coli genome. There is no known biochemical function for Cd in E. coli, making it an ideal vector for studying distinct physiological processes within a single organism. The uptake of Cd and associated isotopic fractionation was determined for both normal cells and those expressing CdCA. It was found that whole cells always exhibited a preference for the light isotopes of Cd, regardless of the expression of CdCA; adsorption of Cd to cell surfaces was not seen to cause isotopic fractionation. However, the cleaning procedure employed exerted a strong control on the observed isotopic composition of cells. Using existing protein purification techniques, we measured the Cd isotopic composition of different subcellular fractions of E

Isotope exchange in oxide-containing catalyst

Science.gov (United States)

Brown, Kenneth G. (Inventor); Upchurch, Billy T. (Inventor); Hess, Robert V. (Inventor); Miller, Irvin M. (Inventor); Schryer, David R. (Inventor); Sidney, Barry D. (Inventor); Wood, George M. (Inventor); Hoyt, Ronald F. (Inventor)

1989-01-01

A method of exchanging rare-isotope oxygen for common-isotope oxygen in the top several layers of an oxide-containing catalyst is disclosed. A sample of an oxide-containing catalyst is exposed to a flowing stream of reducing gas in an inert carrier gas at a temperature suitable for the removal of the reactive common-isotope oxygen atoms from the surface layer or layers of the catalyst without damaging the catalyst structure. The reduction temperature must be higher than any at which the catalyst will subsequently operate. Sufficient reducing gas is used to allow removal of all the reactive common-isotope oxygen atoms in the top several layers of the catalyst. The catalyst is then reoxidized with the desired rare-isotope oxygen in sufficient quantity to replace all of the common-isotope oxygen that was removed.

Isotope separation process

International Nuclear Information System (INIS)

Cox, D.M.; Maas, E.T.

1982-01-01

Processes are disclosed for the separation of isotopes of an element comprising vaporizing uranyl compounds having the formula (UO2a2)n, where a is a monovalent anion and n in an integer from 2 to 4, the compounds having an isotopically shifted infrared absorption spectrum associated with uranyl ions containing said element which is to be separated, and then irradiating the uranyl compound with infrared radiation which is preferentially absorbed by a molecular vibration of uranyl ions of the compound containing a predetermined isotope of that element so that excited molecules of the compound are provided which are enriched in the molecules of the compound containing that predetermined isotope, thus enabling separation of these excited molecules. The processes disclosed include separation of the excited molecules by irradiating under conditions such that the excited molecules dissociate, and also separating the excited molecules by a discrete separation step. The latter includes irradiating the excited molecules by a second infrared laser in order to convert the excited molecules into a separable product, or also by chemically converting the excited molecules, preferably by reaction with a gaseous reactant

The isotope separation by ion exchange chromatography. Application to the lithium isotopes separation

International Nuclear Information System (INIS)

Albert, M.G.; Barre, Y.; Neige, R.

1993-01-01

In this work is described the used study step to demonstrate the industrial feasibility of a lithium isotopes separation process by ion exchange chromatography. After having recalled how is carried out the exchange reaction between the lithium isotopes bound on the cations exchanger resin and those which are in solution and gave the ion exchange chromatography principle, the authors establish a model which takes into account the cascade theory already used for enriched uranium production. The size parameters of this model are: the isotopic separation factor (which depends for lithium of the ligands nature and of the coordination factor), the isotopic exchange kinetics and the mass flow (which depends of the temperature, the lithium concentration, the resins diameter and the front advance). The way they have to be optimized and the implementation of the industrial process are given. (O.M.)

Isotope mixtures of hydrogen in vanadium

International Nuclear Information System (INIS)

Mecking-Schloetensack, P.

1982-03-01

The properties of isotope-mixtures of Protium and Deuterium stored in Vanadium have been studied. Protium and Deuterium are existing as interstitial-atoms on tetrahedral sites as well as on octahedral sites in this system. This feature leads to large isotopic-effects between the two isotopes. The dependence of the thermodynamic functions like heat of solution, nonconfigurational entropy, specific heat and ordering temperatures from the composition of the isotope-mixture has been determined. (orig.)

Clumped-isotope geochemistry of carbonates: A new tool for the reconstruction of temperature and oxygen isotope composition of seawater

Energy Technology Data Exchange (ETDEWEB)

Bernasconi, Stefano M., E-mail: Stefano.bernasconi@erdw.ethz.ch [Geological Institute, ETH Zuerich, Sonneggstrasse 5, 8092 Zuerich (Switzerland); Schmid, Thomas W.; Grauel, Anna-Lena [Geological Institute, ETH Zuerich, Sonneggstrasse 5, 8092 Zuerich (Switzerland); Mutterlose, Joerg [Institut fuer Geologie, Mineralogie und Geophysik, Ruhr Universitaet Bochum, Universitaetsstr. 150, 44801 Bochum (Germany)

2011-06-15

Highlights: > Clumped-isotope thermometry of carbonates is discussed. > Clumped isotopes of Belemnites show higher sea surface temperatures than commonly assumed for the lower Cretaceous. > The potential of clumped-isotope measurement on foraminifera is discussed. - Abstract: Clumped-isotope geochemistry deals with State of ordering of rare isotopes in molecules, in particular with their tendency to form bonds with other rare isotopes rather than with the most abundant ones. Among its possible applications, carbonate clumped-isotope thermometry is the one that has gained most attention because of the wide potential of applications in many disciplines of the earth sciences. In particular, it allows reconstructing the temperature of formation of carbonate minerals without knowledge of the isotopic composition of the water from which they were formed. In addition, the O isotope composition of the waters from which they were formed can be calculated using the {delta}{sup 18}O of the same carbonate sample. This feature offers new approaches in paleoclimatology for reconstructing past global geochemical cycles. In this contribution two applications of this method are presented. First the potential of a new analytical method of measurement of clumped isotopes on small samples of foraminifera, for high-resolution SST and seawater {delta}{sup 18}O reconstructions from marine sediments is shown. Furthermore the potential of clumped isotope analysis of belemnites, for reconstructing seawater {delta}{sup 18}O and temperatures in the Cretaceous is shown.

Recent development in isotope ratio mass spectrometry

International Nuclear Information System (INIS)

Platzner, I.

1992-01-01

Within the limited of this review the following topics will be briefly discussed: a) Accuracy, precision, internal relative standard deviation (RISD) and external relative standard deviation (RESD) of isotope ratio measurements. With advanced instrumentation and use of standard reference materials, high accuracy and RESD = 0.002% (or better) may be achieved; b) The advantages of modern automatic isotope ratio mass spectrometer are briefly described. Computer controlled operation and data acquisition, and multiple ion collection are the recent important improvement; c) The isotopic fractionation during the course of isotope ratio measurement is considered as a major source of errors in thermal ionization of metallic elements. The phenomenon in strontium, neodymium, uranium, lead and calcium and methods to correct the measured data are discussed; d) Applications of isotope ratio mass spectrometry in atomic weight determinations, the isotope dilution technique, isotope geology, and isotope effects in biological systems are described together with specific applications in various research and technology area. (author)

Isotope-based quantum information

CERN Document Server

G Plekhanov, Vladimir

2012-01-01

The present book provides to the main ideas and techniques of the rapid progressing field of quantum information and quantum computation using isotope - mixed materials. It starts with an introduction to the isotope physics and then describes of the isotope - based quantum information and quantum computation. The ability to manipulate and control electron and/or nucleus spin in semiconductor devices provides a new route to expand the capabilities of inorganic semiconductor-based electronics and to design innovative devices with potential application in quantum computing. One of the major challenges towards these objectives is to develop semiconductor-based systems and architectures in which the spatial distribution of spins and their properties can be controlled. For instance, to eliminate electron spin decoherence resulting from hyperfine interaction due to nuclear spin background, isotopically controlled devices are needed (i.e., nuclear spin-depleted). In other emerging concepts, the control of the spatial...

Compelling Research Opportunities using Isotopes

International Nuclear Information System (INIS)

2009-01-01

Isotopes are vital to the science and technology base of the US economy. Isotopes, both stable and radioactive, are essential tools in the growing science, technology, engineering, and health enterprises of the 21st century. The scientific discoveries and associated advances made as a result of the availability of isotopes today span widely from medicine to biology, physics, chemistry, and a broad range of applications in environmental and material sciences. Isotope issues have become crucial aspects of homeland security. Isotopes are utilized in new resource development, in energy from bio-fuels, petrochemical and nuclear fuels, in drug discovery, health care therapies and diagnostics, in nutrition, in agriculture, and in many other areas. The development and production of isotope products unavailable or difficult to get commercially have been most recently the responsibility of the Department of Energy's Nuclear Energy program. The President's FY09 Budget request proposed the transfer of the Isotope Production program to the Department of Energy's Office of Science in Nuclear Physics and to rename it the National Isotope Production and Application program (NIPA). The transfer has now taken place with the signing of the 2009 appropriations bill. In preparation for this, the Nuclear Science Advisory Committee (NSAC) was requested to establish a standing subcommittee, the NSAC Isotope Subcommittee (NSACI), to advise the DOE Office of Nuclear Physics. The request came in the form of two charges: one, on setting research priorities in the short term for the most compelling opportunities from the vast array of disciplines that develop and use isotopes and two, on making a long term strategic plan for the NIPA program. This is the final report to address charge 1. NSACI membership is comprised of experts from the diverse research communities, industry, production, and homeland security. NSACI discussed research opportunities divided into three areas: (1) medicine

Compelling Research Opportunities using Isotopes

Energy Technology Data Exchange (ETDEWEB)

None

2009-04-23

Isotopes are vital to the science and technology base of the US economy. Isotopes, both stable and radioactive, are essential tools in the growing science, technology, engineering, and health enterprises of the 21st century. The scientific discoveries and associated advances made as a result of the availability of isotopes today span widely from medicine to biology, physics, chemistry, and a broad range of applications in environmental and material sciences. Isotope issues have become crucial aspects of homeland security. Isotopes are utilized in new resource development, in energy from bio-fuels, petrochemical and nuclear fuels, in drug discovery, health care therapies and diagnostics, in nutrition, in agriculture, and in many other areas. The development and production of isotope products unavailable or difficult to get commercially have been most recently the responsibility of the Department of Energy's Nuclear Energy program. The President's FY09 Budget request proposed the transfer of the Isotope Production program to the Department of Energy's Office of Science in Nuclear Physics and to rename it the National Isotope Production and Application program (NIPA). The transfer has now taken place with the signing of the 2009 appropriations bill. In preparation for this, the Nuclear Science Advisory Committee (NSAC) was requested to establish a standing subcommittee, the NSAC Isotope Subcommittee (NSACI), to advise the DOE Office of Nuclear Physics. The request came in the form of two charges: one, on setting research priorities in the short term for the most compelling opportunities from the vast array of disciplines that develop and use isotopes and two, on making a long term strategic plan for the NIPA program. This is the final report to address charge 1. NSACI membership is comprised of experts from the diverse research communities, industry, production, and homeland security. NSACI discussed research opportunities divided into three areas: (1

ICP-MS for isotope ratio measurement

Science.gov (United States)

The use of stable isotopes in mineral nutrition research has become a fundamental aspect of conducting this research. A gradual transition has occurred, now virtually complete, from radioactive isotope studies to those using stable isotopes. Although primarily used in human research, mineral stable ...

Isotope analysis of closely adjacent minerals

International Nuclear Information System (INIS)

Smith, M.P.

1990-01-01

This patent describes a method of determining an indicator of at least one of hydrocarbon formation, migration, and accumulation during mineral development. It comprises: searching for a class of minerals in a mineral specimen comprising more than one class of minerals; identifying in the mineral specimen a target sample of the thus searched for class; directing thermally pyrolyzing laser beam radiation onto surface mineral substance of the target sample in the mineral specimen releasing surface mineral substance pyrolysate gases therefrom; and determining isotope composition essentially of the surface mineral substance from analyzing the pyrolysate gases released from the thus pyrolyzed target sample, the isotope composition including isotope(s) selected from the group consisting of carbon, hydrogen, and oxygen isotopes; determining an indicator of at least one of hydrocarbon formation, migration, and accumulation during mineral development of the target mineral from thus determined isotope composition of surface mineral substance pyrolysate

Stable Oxygen-18 and Deuterium Isotopes

DEFF Research Database (Denmark)

Müller, Sascha

The application of stable Oxygen-18 (18O) and Deuterium (2H) isotopes, as a tracer for fluxes between different compartments of the water cycle was subject of the present PhD-thesis. During a three year period, temporal data from a wide range of water cycle constituents was collected from...... the Skjern River catchment, Denmark. The presented applications focused on studying the isotopic 'input signal' to the hydrosphere in the form of precipitation, the isotopic 'output signal' with its related dynamic processes at a coastal saltwater-freshwater interface (groundwater isotopes) and the temporal...... development within a given lowland headwater catchment (stream water isotopes). Based on our investigations on the precipitation isotopic composition a local meteoric water line (LMWL) was constructed and expressed as: δ2H=7.4 δ18O + 5.36‰. Moreover, we showed that under maritime temperature climate influence...

Stable Isotope Group 1984 progress report

International Nuclear Information System (INIS)

Lyon, G.L.

1985-04-01

The work of the group in 1984 is described and includes studies in isotope geology, isotope hydrology, geochronology, isotope biology and mass spectrometer instrumentation. Geothermal studies have decreased compared to other years, but major data summaries were made for Wairakei and Ngawha. The hydrology of Whakarewarewa and Rotorua is being elucidated using water isotopes. Models of the subsurface flows at Kawerau and Ngawha are being made to relate fluid to mineral isotope compositions. A study of the δ 13 C and δ 34 S compositions of New Zealand oils has been started. Groups of oils of related origin are being defined, and compositions will be compared with those of potential source rocks. A method was developed for isotope analysis of sulphur in rocks. The isotopic composition of water is being used to identify and characterise groundwater aquifers in the Wairarapa and at Poverty Bay. Stable carbon isotopes have been used to identify food sources for invertebrates, and to show biochemical pathways in lactation by cows. The geochronology group is involved in major studies in Antarctica, using U-Pb, Rb-Sr and K-Ar methods. Rocks from North Victoria Land, Marie Byrd Land and the USARP mountains are being compared with possible correlatives in New Zealand and Argentina. Strontium isotope data is being applied to the origin of magmas in several regions of New Zealand. The K-Ar data is being stored on computer files. Fission track measurements are being applied to unravel uplift histories in Westland and Taranaki

Isotopes a very short introduction

CERN Document Server

Ellam, Rob

2016-01-01

An isotope is a variant form of a chemical element, containing a different number of neutrons in its nucleus. Most elements exist as several isotopes. Many are stable while others are radioactive, and some may only exist fleetingly before decaying into other elements. In this Very Short Introduction, Rob Ellam explains how isotopes have proved enormously important across all the sciences and in archaeology. Radioactive isotopes may be familiar from their use in nuclear weapons, nuclear power, and in medicine, as well as in carbon dating. They have been central to establishing the age of the Earth and the origins of the solar system. Combining previous and new research, Ellam provides an overview of the nature of stable and radioactive isotopes, and considers their wide range of modern applications. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subjec...

Correlated optical and isotopic nanoscopy

Science.gov (United States)

Saka, Sinem K.; Vogts, Angela; Kröhnert, Katharina; Hillion, François; Rizzoli, Silvio O.; Wessels, Johannes T.

2014-04-01

The isotopic composition of different materials can be imaged by secondary ion mass spectrometry. In biology, this method is mainly used to study cellular metabolism and turnover, by pulsing the cells with marker molecules such as amino acids labelled with stable isotopes (15N, 13C). The incorporation of the markers is then imaged with a lateral resolution that can surpass 100 nm. However, secondary ion mass spectrometry cannot identify specific subcellular structures like organelles, and needs to be correlated with a second technique, such as fluorescence imaging. Here, we present a method based on stimulated emission depletion microscopy that provides correlated optical and isotopic nanoscopy (COIN) images. We use this approach to study the protein turnover in different organelles from cultured hippocampal neurons. Correlated optical and isotopic nanoscopy can be applied to a variety of biological samples, and should therefore enable the investigation of the isotopic composition of many organelles and subcellular structures.

Isotope methods in hydrology

International Nuclear Information System (INIS)

Moser, H.; Rauert, W.

1980-01-01

Of the investigation methods used in hydrology, tracer methods hold a special place as they are the only ones which give direct insight into the movement and distribution processes taking place in surface and ground waters. Besides the labelling of water with salts and dyes, as in the past, in recent years the use of isotopes in hydrology, in water research and use, in ground-water protection and in hydraulic engineering has increased. This by no means replaces proven methods of hydrological investigation but tends rather to complement and expand them through inter-disciplinary cooperation. The book offers a general introduction to the application of various isotope methods to specific hydrogeological and hydrological problems. The idea is to place the hydrogeologist and the hydrologist in the position to recognize which isotope method will help him solve his particular problem or indeed, make a solution possible at all. He should also be able to recognize what the prerequisites are and what work and expenditure the use of such methods involves. May the book contribute to promoting cooperation between hydrogeologists, hydrologists, hydraulic engineers and isotope specialists, and thus supplement proven methods of investigation in hydrological research and water utilization and protection wherever the use of isotope methods proves to be of advantage. (orig./HP) [de

Effect of captopril on renal blood flow in renal artery stenosis assessed by positron tomography with rubidium-82

International Nuclear Information System (INIS)

Tamaki, N.; Alpert, N.M.; Rabito, C.A.; Barlai-Kovach, M.; Correia, J.A.; Strauss, H.W.

1988-01-01

The sequence and magnitude of acute changes in renal blood flow following administration of captopril were determined in a canine model of acute unilateral renal artery stenosis using rubidium-82 and positron emission tomography. Data were recorded in each of nine dogs under three conditions: 1) during a baseline control interval, 2) during renal artery stenosis, and 3) during stenosis with intravenous injection of captopril (1.2 mg/kg). Mean arterial blood pressure was 108 +/- 12 mm Hg at control, increased significantly to 125 +/- 13 mm Hg (p less than 0.01) during stenosis, and decreased to 98 +/- 13 mm/Hg (p less than 0.01) after captopril infusion. Mean renal blood flow was calculated using a steady state single compartment model from the images produced by positron emission tomography. The estimated flow to the affected kidney was 3.37 +/- 1.48 ml/min/g at control, 0.86 +/- 0.62 ml/min/g during stenosis (p less than 0.01), and 0.64 +/- 0.57 ml/min/g after captopril administration (p = NS compared with precaptopril value). The estimated flow to the contralateral kidney was minimally reduced from a baseline of 3.84 +/- 0.95 to 3.24 +/- 1.13 ml/min/g (p = NS) during stenosis and increased after captopril infusion (4.08 +/- 0.94 ml/min/g; p = 0.01). These data suggest that repetitive imaging with positron emission tomography can be used to delineate acute changes in renal perfusion following captopril administration

Isotope separation by standing waves

International Nuclear Information System (INIS)

Altshuler, S.

1984-01-01

The separation of isotopes is accomplished by scattering a beam of particles from a standing electromagnetic wave. The particles may consist of either atoms or molecules, the beam having in either case a desired isotope and at least one other. The particle beam is directed so as to impinge on the standing electromagnetic wave, which may be a light wave. The particles, that is, the atomic or molecular quantum-mechanical waves, see basically a diffraction grating corresponding to the troughs and peaks of the electromagnetic wave. The frequency of the standing electromagnetic wave substantially corresponds to an internal energy level-transition of the desired isotope. Accordingly, the desired isotope is spatially separated by being scattered or diffracted. (author)

Method and device for isotope separation

International Nuclear Information System (INIS)

Dawson, J.M.

1976-01-01

The method works with a converted Q machine. The plasma containing the isotopes to be separated is crossed by a magnetic field running in the direction of the plasma column. More energy is transfered to the chosen isotope by oscillating magnetic and/or electric fields or by sound waves by using the specific resonance frequency for the selected isotope. The isotopes thus heated to different extents can be separated according to various methods given in the patent claims. (GG) [de

Laser isotope separation

International Nuclear Information System (INIS)

1976-01-01

The claimed invention is a method of isotope separation based on the unimolecular decomposition of vibrationally excited negative ions which are produced in the reaction of thermal electrons and molecules which have been vibrationally excited in an isotope selective manner. This method is especially applicable to molecules represented by the formula MF 6 wherein M is selected from the group consisting of U, S, W, Se, Te, Mo, Re and Tc

Radiogenic isotope geochemistry of sedimentary and aquatic systems

International Nuclear Information System (INIS)

Stille, P.; Shields, G.

1997-01-01

The following topics are discussed: Basic principles of isotopic geochemistry; weathering; isotopic geochemistry of river water; isotopic geochemistry in the environment; isotopic composition of seawater past and present (Sr, Nd, Pb, Os, Ce); isotope geochemistry of detrital and authigenic clay minerals in marine sediemnts (Rb-Sr, K-Ar, O); the Sm-N isotope system in detrital and authigenic argillaceous sediments. (SR), provided they are of exceptional interest and focused on a single topic. (orig./SR)

Radiogenic isotope geochemistry of sedimentary and aquatic systems

Energy Technology Data Exchange (ETDEWEB)

Stille, P.; Shields, G. [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France). Centre de Sedimentologie et Geochimie de la Surface

1997-12-31

The following topics are discussed: Basic principles of isotopic geochemistry; weathering; isotopic geochemistry of river water; isotopic geochemistry in the environment; isotopic composition of seawater past and present (Sr, Nd, Pb, Os, Ce); isotope geochemistry of detrital and authigenic clay minerals in marine sediemnts (Rb-Sr, K-Ar, O); the Sm-N isotope system in detrital and authigenic argillaceous sediments. (SR), provided they are of exceptional interest and focused on a single topic. (orig./SR)

Sulphur isotope variations in the atmosphere

International Nuclear Information System (INIS)

Newman, L.; Krouse, H.R.; Grinenko, V.A.

1991-01-01

The measurement of the isotope ratios of sulphur and oxygen can in principal be used to assess sulphur inputs into, transformation within, and removal from the atmosphere. Major inputs arise from both anthropogenic and biogenic activities. Transformations arise from oxidation, neutralization, and other chemical reactions. Advection causes dilution and the main removal processes are dry deposition (governed by gravitation and diffusion) and rain. The admixture of sources can be discerned from their isotopic signatures whereas transformations and removal can be followed from the isotopic fractionation that might occur. In this chapter, the atmospheric sulphur cycle and the associated chemistry are summarized. Also presented is information on natural isotopic variations and fundamental concepts relating to the use of isotopic data to delineate anthropogenic S in the atmosphere. Examples of successful applications of these concepts are given. Finally, consideration is given to the potential of using isotopically enriched sulphur to study transport and transformation of atmospheric S compounds. Refs, figs and tabs

Method and apparatus for separating uranium isotopes

International Nuclear Information System (INIS)

Bernstein, E.R.

1977-01-01

A uranium compound in the solid phase (uranium borohydride four) is subjected to radiation of a first predetermined frequency that excites the uranium-235 isotope-bearing molecules but not the uranium-238 isotope-bearing molecules. The compound is simultaneously subjected to radiation of a second predetermined frequency which causes the excited uranium-235 isotope-bearing molecules to chemically decompose but which does not affect the uranium-238 isotope-bearing molecules. Sufficient heat is then applied to the irradiated compound in the solid phase to vaporize the non-decomposed uranium-238 isotope-bearing molecules but not the decomposed uranium-235 isotope-bearing molecules, thereby physically separating the uranium-235 isotope-bearing molecules from the uranium-238 isotope-bearing molecules. The uranium compound sample in the solid phase is deposited or grown in an elongated tube supported within a dewar vessel having a clear optical path tail section surrounded by a coolant. Two sources of radiation are focused on the uranium compound sample. A heating element is attached to the elongated tube to vaporize the irradiated compound

French days on stable isotopes

International Nuclear Information System (INIS)

2000-01-01

These first French days on stable isotopes took place in parallel with the 1. French days of environmental chemistry. Both conferences had common plenary sessions. The conference covers all aspects of the use of stable isotopes in the following domains: medicine, biology, environment, tracer techniques, agronomy, food industry, geology, petroleum geochemistry, cosmo-geochemistry, archaeology, bio-geochemistry, hydrology, climatology, nuclear and particle physics, astrophysics, isotope separations etc.. Abstracts available on CD-Rom only. (J.S.)

Laser Isotope Enrichment for Medical and Industrial Applications

Energy Technology Data Exchange (ETDEWEB)

Leonard Bond

2006-07-01

Laser Isotope Enrichment for Medical and Industrial Applications by Jeff Eerkens (University of Missouri), Jay Kunze (Idaho State University), and Leonard Bond (Idaho National Laboratory) The principal isotope enrichment business in the world is the enrichment of uranium for commercial power reactor fuels. However, there are a number of other needs for separated isotopes. Some examples are: 1) Pure isotopic targets for irradiation to produce medical radioisotopes. 2) Pure isotopes for semiconductors. 3) Low neutron capture isotopes for various uses in nuclear reactors. 4) Isotopes for industrial tracer/identification applications. Examples of interest to medicine are targets to produce radio-isotopes such as S-33, Mo-98, Mo-100, W-186, Sn-112; while for MRI diagnostics, the non-radioactive Xe-129 isotope is wanted. For super-semiconductor applications some desired industrial isotopes are Si-28, Ga-69, Ge-74, Se-80, Te-128, etc. An example of a low cross section isotope for use in reactors is Zn-68 as a corrosion inhibitor material in nuclear reactor primary systems. Neutron activation of Ar isotopes is of interest in industrial tracer and diagnostic applications (e.g. oil-logging). . In the past few years there has been a sufficient supply of isotopes in common demand, because of huge Russian stockpiles produced with old electromagnetic and centrifuge separators previously used for uranium enrichment. Production of specialized isotopes in the USA has been largely accomplished using old ”calutrons” (electromagnetic separators) at Oak Ridge National Laboratory. These methods of separating isotopes are rather energy inefficient. Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation

Laser Isotope Enrichment for Medical and Industrial Applications

International Nuclear Information System (INIS)

Leonard Bond

2006-01-01

Laser Isotope Enrichment for Medical and Industrial Applications by Jeff Eerkens (University of Missouri), Jay Kunze (Idaho State University), and Leonard Bond (Idaho National Laboratory) The principal isotope enrichment business in the world is the enrichment of uranium for commercial power reactor fuels. However, there are a number of other needs for separated isotopes. Some examples are: (1) Pure isotopic targets for irradiation to produce medical radioisotopes. (2) Pure isotopes for semiconductors. (3) Low neutron capture isotopes for various uses in nuclear reactors. (4) Isotopes for industrial tracer/identification applications. Examples of interest to medicine are targets to produce radio-isotopes such as S-33, Mo-98, Mo-100, W-186, Sn-112; while for MRI diagnostics, the non-radioactive Xe-129 isotope is wanted. For super-semiconductor applications some desired industrial isotopes are Si-28, Ga-69, Ge-74, Se-80, Te-128, etc. An example of a low cross section isotope for use in reactors is Zn-68 as a corrosion inhibitor material in nuclear reactor primary systems. Neutron activation of Ar isotopes is of interest in industrial tracer and diagnostic applications (e.g. oil-logging). . In the past few years there has been a sufficient supply of isotopes in common demand, because of huge Russian stockpiles produced with old electromagnetic and centrifuge separators previously used for uranium enrichment. Production of specialized isotopes in the USA has been largely accomplished using old ''calutrons'' (electromagnetic separators) at Oak Ridge National Laboratory. These methods of separating isotopes are rather energy inefficient. Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, Tanja C. W.; Schierbeek, Henk; Houtekamer, Marco; van Engeland, Tom; Derrien, Delphine; Stal, Lucas J.; Boschker, Henricus T. S.

2015-01-01

We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ(13)C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

2015-01-01

We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of d13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence, although

Comparison of gas chromatography/isotope ratio mass spectrometry and liquid chromatography/isotope ratio mass spectrometry for carbon stable-isotope analysis of carbohydrates

NARCIS (Netherlands)

Moerdijk-Poortvliet, T.C.W.; Schierbeek, H.; Houtekamer, M.; van Engeland, T.; Derrien, D.; Stal, L.J.; Boschker, H.T.S.

2015-01-01

Rationale: We compared gas chromatography/isotope ratio mass spectrometry (GC/IRMS) and liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) for the measurement of δ13C values in carbohydrates. Contrary to GC/IRMS, no derivatisation is needed for LC/IRMS analysis of carbohydrates. Hence,

Beneficial uses and production of isotopes

International Nuclear Information System (INIS)

2000-01-01

Radioactive and stable isotopes are widely used in many sectors including medicine, industry and research. Practically all countries in the world are using isotopes in one way or another. In many cases, isotopes have no substitute and in most of their applications they are more effective and cheaper than alternative techniques or processes. The production of isotopes is less widespread, but more than fifty countries have isotope production or separation facilities operated for domestic supply, and sometimes for international markets. In spite of the importance of isotopes in economic and social terms, comprehensive statistical data on volumes or values of isotope production and uses are not readily available. This lack of information led the NEA to include the topic in its programme of work. The study carried out by the NEA, in co-operation with the International Atomic Energy Agency (IAEA), aimed at collecting and analysing information on various aspects of isotope production and uses in order to highlight key issues and provide findings and recommendations of relevance, in particular, for governmental bodies involved. This report provides data collected in 1999, reviewed and analysed by a group of experts nominated by Member countries. The participating experts and the NEA and IAEA Secretariats endeavored to present consistent and comprehensive information on isotope uses and production in the world. It is recognised, however, that the data and analyses included in the report are by no means exhaustive. The views expressed in the document are those of the participating experts and do not necessarily represent those of the countries concerned. The report is published under the responsibility of the Secretary-General of the OECD. (author)

Plutonium isotope ratios in polychaete worms

International Nuclear Information System (INIS)

Beasley, T.M.; Fowler, S.W.

1976-01-01

Reference is made to recent reports that suggest that terrestrial and aquatic organisms may preferentially take up 238 Pu compared with sup(239+240)Pu. It is stated that although kinetic isotope effects are known to occur in biological systems for low mass number elements, such as H, C and N, such effects are generally discounted with higher mass numbers, and differences in the biological 'uptake' of isotopes of high mass number elements, such as those of Pu, are normally attributable to differences in the chemical or physical forms of the isotopes or to different quantities of isotopes available to organisms. This has been applied to explain differential Pu isotope behaviour in animals under controlled laboratory conditions, but it is not certain that it can be applied to explain anomalies of Pu isotope behaviour in organisms contaminated by nuclear test debris or by wastes from nuclear fuel reprocessing plants. Geochemical weathering may also have an effect. Described here are experiments in which it was found that deposit feeding marine worms living in sediments contaminated in different ways with Pu isotopes did not show preferential accumulation of 238 Pu. The worms had been exposed to different chemical and physical forms of the isotopes, including exposure to laboratory-labelled sediment, sediment collected from a former weapons test site, and sediment contaminated by wastes from a nuclear fuel reprocessing plant. The worms were allowed to accumulate Pu for times of 5 to 40 days. Isotope ratios were determined by α-spectrometric techniques. It is considered that the results are important for environmental samples where Pu activity levels are low. (U.K.)

Resetting of Mg isotopes between calcite and dolomite during burial metamorphism: Outlook of Mg isotopes as geothermometer and seawater proxy

Science.gov (United States)

Hu, Zhongya; Hu, Wenxuan; Wang, Xiaomin; Lu, Yizhou; Wang, Lichao; Liao, Zhiwei; Li, Weiqiang

2017-07-01

Magnesium isotopes are an emerging tool to study the geological processes recorded in carbonates. Calcite, due to its ubiquitous occurrence and the large Mg isotope fractionation associated with the mineral, has attracted great interests in applications of Mg isotope geochemistry. However, the fidelity of Mg isotopes in geological records of carbonate minerals (e.g., calcite and dolomite) against burial metamorphism remains poorly constrained. Here we report our investigation on the Mg isotope systematics of a dolomitized Middle Triassic Geshan carbonate section in eastern China. Magnesium isotope analysis was complemented by analyses of Sr-C-O isotopic compositions, major and trace element concentrations, and petrographic and mineralogical features. Multiple lines of evidence consistently indicated that post-depositional diagenesis of carbonate minerals occurred to the carbonate rocks. Magnesium isotope compositions of the carbonate rocks closely follow a mixing trend between a high δ26Mg dolomite end member and a low δ26Mg calcite end member, irrespective of sample positions in the section and calcite/dolomite ratio in the samples. By fitting the measured Mg isotope data using a two-end member mixing model, an inter-mineral Δ26Mgdolomite-calcite fractionation of 0.72‰ was obtained. Based on the experimentally derived Mg isotope fractionation factors for dolomite and calcite, a temperature of 150-190 °C was calculated to correspond to the 0.72‰ Δ26Mgdolomite-calcite fractionation. Such temperature range matches with the burial-thermal history of the local strata, making a successful case of Mg isotope geothermometry. Our results indicate that both calcite and dolomite had been re-equilibrated during burial metamorphism, and based on isotope mass balance of Mg, the system was buffered by dolomite in the section. Therefore, burial metamorphism may reset Mg isotope signature of calcite, and Mg isotope compositions in calcite should be dealt with caution in

UWIS isotope separator

Energy Technology Data Exchange (ETDEWEB)

Wojtasiewicz, A. [Warsaw Univ., Inst. of Experimental Physics, Nuclear Physics Div., Warsaw (Poland)

1997-12-31

Since 1995 the University of Warsaw Isotope Separator group has participated in the ISOL/IGISOL project at the Heavy Ion Cyclotron. This project consists in installation of an isotope separator (on line with cyclotron heavy ion beam) with a hot plasma ion source (ISOL system) and/or with an ion guide source (IGISOL system). In the report the short description of the present status of the project is presented. 2 figs, 10 refs.

Steric effects on the primary isotope dependence of secondary kinetic isotope effects in hydride transfer reactions in solution: caused by the isotopically different tunneling ready state conformations?

Science.gov (United States)

Maharjan, Binita; Raghibi Boroujeni, Mahdi; Lefton, Jonathan; White, Ormacinda R; Razzaghi, Mortezaali; Hammann, Blake A; Derakhshani-Molayousefi, Mortaza; Eilers, James E; Lu, Yun

2015-05-27

The observed 1° isotope effect on 2° KIEs in H-transfer reactions has recently been explained on the basis of a H-tunneling mechanism that uses the concept that the tunneling of a heavier isotope requires a shorter donor-acceptor distance (DAD) than that of a lighter isotope. The shorter DAD in D-tunneling, as compared to H-tunneling, could bring about significant spatial crowding effect that stiffens the 2° H/D vibrations, thus decreasing the 2° KIE. This leads to a new physical organic research direction that examines how structure affects the 1° isotope dependence of 2° KIEs and how this dependence provides information about the structure of the tunneling ready states (TRSs). The hypothesis is that H- and D-tunneling have TRS structures which have different DADs, and pronounced 1° isotope effect on 2° KIEs should be observed in tunneling systems that are sterically hindered. This paper investigates the hypothesis by determining the 1° isotope effect on α- and β-2° KIEs for hydride transfer reactions from various hydride donors to different carbocationic hydride acceptors in solution. The systems were designed to include the interactions of the steric groups and the targeted 2° H/D's in the TRSs. The results substantiate our hypothesis, and they are not consistent with the traditional model of H-tunneling and 1°/2° H coupled motions that has been widely used to explain the 1° isotope dependence of 2° KIEs in the enzyme-catalyzed H-transfer reactions. The behaviors of the 1° isotope dependence of 2° KIEs in solution are compared to those with alcohol dehydrogenases, and sources of the observed "puzzling" 2° KIE behaviors in these enzymes are discussed using the concept of the isotopically different TRS conformations.

High atomic weight isotope separator

International Nuclear Information System (INIS)

Book, D.L.

1978-01-01

A continuously operating device is described which separates one isotopic species of a given element from a mixture. The given element is vaporized and formed into a neutral beam containing the isotopes desired to be separated. The plasma is accelerated through a laser beam which is formed by two separate lasers which operate in the continuous wave mode in which the beams are as nearly as possible in the same beam path. The two laser output beams excite and ionize the isotope of interest while leaving the remaining atoms unaffected. The ionized isotopes are then separated from the beam by an electrostatic deflection technique and the unaffected atoms continue on in their path and are directed to a recovery device

Optical Magnetometry Using Multiphoton Transitions

Science.gov (United States)

Degenkolb, Skyler M.

Optical magnetometry plays a critical role in low-energy precision measurements and numerous other applications. In particular, permanent electric dipole moment (EDM) searches impose strict requirements on magnetic field sensitivity of the underlying atomic or molecular species. Other magnetometer properties - such as chemical reactivity, dielectric strength, and interaction cross-sections with other species - also impose limitations on experimental conditions. Here, we explore a novel approach to optical magnetometry, using multiphoton transitions of diamagnetic atoms to detect Larmor precession of polarized nuclei. Resonant probes are possible at moderate ultraviolet wavelengths, and hyperfine structure couples spin precession to fluorescence transitions with negligible backgrounds; paramagnetic rotation due to intensity-dependent dispersion may also be detectable. Nuclear spins and nonlinear optical excitation introduce new degrees of freedom, and evade limitations arising from rapid electronic decoherence. This dissertation reports progress towards two-photon optical magnetometry using ytterbium, rubidium, and xenon. We characterize the influence of probe polarization and magnetic fields on fluorescence spectra, for one- and two-photon continuous-wave (cw) excitation of ytterbium. Resolved hyperfine and isotope structure allow us to use spin-zero isotopes for diagnostics and normalization, and we develop analysis for overlapping two-photon resonances. We also report measurements of two-photon excitation in ytterbium and rubidium using picosecond laser pulses, and in xenon using a cw laser. Although hyperfine structure is unresolved, the rubidium measurements are sensitive to probe field polarization. Fluorescence spectra from two-photon excitation of ytterbium with femtosecond pulses show modulation when the repetition rate changes. Although techniques for polarizing noble gas nuclei are mature, existing cell designs are incompatible with two

Isotopic Discrimination During Leaf Litter Decomposition

Science.gov (United States)

Ngao, J.; Rubino, M.

2006-12-01

Methods involving stable isotopes have been successfully applied since decades in various research fields. Tracing 13C natural abundance in ecosystem compartments greatly enhanced the understanding of the C fluxes in the plant-soil-atmosphere C exchanges when compartments present different C isotopic signatures (i.e. atmospheric CO2 vs photosynthetic leaves, C3 vs C4; etc.). However, the assumption that no isotopic discrimination occurs during respiration is commonly made in numbers of C isotope-based ecological studies. Furthermore, verifications of such assumption are sparse and not enough reliable. The aim of our study is to assess the potential isotopic discrimination that may occur during litter decomposition. Leaf litter from an Arbutus unedo (L.) stand (Tolfa, Italy) was incubated in 1L jars, under constant laboratory conditions (i.e. 25 ° C and 135% WC). During the entire incubation period, gravimetric mass loss, litter respiration rates and the isotopic composition of respired CO2 are monitored at regular intervals. Data from 7 months of incubation will be presented and discussed. After two months, the litter mass loss averaged 16% of initial dry mass. During the same time-period, the respiration rate decreased significantly by 58% of the initial respiration rate. Isotopic compositions of respired CO2 ranged between -27.95‰ and - 25.69‰. Mean values did not differ significantly among the sampling days, in spite of an apparent enrichment in 13C of respired CO2 with time. The significance of these isotopic enrichment will be determined at a longer time scale. They may reveal both/either a direct microbial discrimination during respiration processes and/or a use of different litter compounds as C source along time. Further chemical and compound-specific isotopic analysis of dry matter will be performed in order to clarify these hypotheses. This work is part of the "ALICE" project, funded by the European Union's Marie Curie Fellowship Actions that aims to

Stable Isotope Systematics of Martian Perchlorate

Science.gov (United States)

Martin, P.; Farley, K. A.; Archer, D., Jr.; Atreya, S. K.; Conrad, P. G.; Eigenbrode, J. L.; Fairen, A.; Franz, H. B.; Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; Malespin, C.; Ming, D. W.; Navarro-Gonzalez, R.; Sutter, B.

2015-12-01

Chlorine isotopic compositions in HCl released during evolved gas analysis (EGA) runs have been detected by the Sample Analysis at Mars (SAM) instrument on the Curiosity rover ranging from approximately -9‰ to -50‰ δ37Cl, with two spatially and isotopically separated groups of samples averaging -15‰ and -45‰. These extremely low values are the first such detection of any known natural material; common terrestrial values very rarely exceed ±5‰, and the most extreme isotopic signature yet detected elsewhere in the solar system are values of around +24‰ on the Moon. The only other known location in the solar system with large negative chlorine isotopes is the Atacama Desert, where perchlorate with -14‰ δ37Cl has been detected. The Atacama perchlorate has unusual Δ17O signatures associated with it, indicating a formation mechanism involving O3, which suggests an atmospheric origin of the perchlorate and associated large isotopic anomalies. Identification of non-zero positive Δ17O signatures in the O2 released during EGA runs would allow definitive evidence for a similar process having occurred on Mars. Perchlorate is thought to be the most likely source of HCl in EGA runs due to the simultaneous onset of O2 release. If perchlorate is indeed the HCl source, atmospheric chemistry could be responsible for the observed isotopic anomalies, with variable extents of perchlorate production producing the isotopic variability. However, chloride salts have also been observed to release HCl upon heating; if the timing of O2 release is merely coincidental, observed HCl could be coming from chlorides. At thermodynamic equilibrium, the fractionation factor of perchlorate reduction is 0.93, meaning that differing amounts of post-deposition reduction of isotopically normal perchlorate to chloride could account for the highly variable Cl isotopes. Additionally, post-deposition reduction could account for the difference between the two Cl isotopic groups if perchlorate

Detecting isotopic ratio outliers

Science.gov (United States)

Bayne, C. K.; Smith, D. H.

An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers.

Detecting isotopic ratio outliers

International Nuclear Information System (INIS)

Bayne, C.K.; Smith, D.H.

1986-01-01

An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers

Stable isotope research pool inventory

International Nuclear Information System (INIS)

1984-03-01

This report contains a listing of electromagnetically separated stable isotopes which are available at the Oak Ridge National Laboratory for distribution for nondestructive research use on a loan basis. This inventory includes all samples of stable isotopes in the Research Materials Collection and does not designate whether a sample is out on loan or is in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

Treatment and storage of hydrogen isotopes

International Nuclear Information System (INIS)

Jung, H. S.; Lee, H. S.; An, D. H.; Kim, K. R.; Lee, S. H.; Choi, H. J.; Back, S. W.; Kang, H. S.; Eom, K. Y.; Lee, M. S.

2000-01-01

Storage of gaseous hydrogen isotopes in a cylinder is a well-established technology. However, Immobilization in the solid form is preferred for long-term storage of radioactive isotope gas because of the concern for leakage of the gas. The experimental thermodynamic p-c-T data show that Ti and U soak up hydrogen isotope gas at a temperature of a few hundred .deg. C and modest pressures. It was found that more hydrogen is dissolved in the metal than deuterium at constant pressure. Thus, the lighter isotope tends to be enriched in the solid phase

Noncovalent Hydrogen Isotope Effects

Science.gov (United States)

Buchachenko, A. L.; Breslavskaya, N. N.

2018-02-01

Zero-point energies (ZPE) and isotope effects, induced by intermolecular, noncovalent vibrations, are computed and tested by experimental data. The ZPE differences of H- and D-complexes of water with hydrogen, methane, and water molecules are about 100-300 cal/mol; they result to isotope effects IE of 1.20-1.70. Semi-ionic bonds between metal ions and water ligands in M(H2O) 6 2+ complexes are much stronger; their ZPEs are about 12-14 kcal/mol per molecule and result to IE of 1.9-2.1 at 300 K. Protonated (deuterated) water and biwater exhibit the largest ZPE differences and isotope effects; the latter are 25-28 and 12-13 for water and biwater, respectively. Noncovalent IEs contribute markedly into the experimentally measured effects and explain many anomalous and even magic properties of the effects, such as the dependence of IE on the solvents and on the presence of the third substances, enormously large isotope effects at the mild conditions, the difference between IEs measured in the reactions of individual protiated and deuterated compounds and those measured in their mixture. Noncovalent IEs are not negligible and should be taken into account to make correct and substantiated conclusions on the reaction mechanisms. The kinetic equations are derived for the total isotope effects, which include noncovalent IEs as additive factors.

Magnesium isotope systematics in Martian meteorites

Science.gov (United States)

Magna, Tomáš; Hu, Yan; Teng, Fang-Zhen; Mezger, Klaus

2017-09-01

Magnesium isotope compositions are reported for a suite of Martian meteorites that span the range of petrological and geochemical types recognized to date for Mars, including crustal breccia Northwest Africa (NWA) 7034. The δ26Mg values (per mil units relative to DSM-3 reference material) range from -0.32 to -0.11‰; basaltic shergottites and nakhlites lie to the heavier end of the Mg isotope range whereas olivine-phyric, olivine-orthopyroxene-phyric and lherzolitic shergottites, and chassignites have slightly lighter Mg isotope compositions, attesting to modest correlation of Mg isotopes and petrology of the samples. Slightly heavier Mg isotope compositions found for surface-related materials (NWA 7034, black glass fraction of the Tissint shergottite fall; δ26Mg > -0.17‰) indicate measurable Mg isotope difference between the Martian mantle and crust but the true extent of Mg isotope fractionation for Martian surface materials remains unconstrained. The range of δ26Mg values from -0.19 to -0.11‰ in nakhlites is most likely due to accumulation of clinopyroxene during petrogenesis rather than garnet fractionation in the source or assimilation of surface material modified at low temperatures. The rather restricted range in Mg isotope compositions between spatially and temporally distinct mantle-derived samples supports the idea of inefficient/absent major tectonic cycles on Mars, which would include plate tectonics and large-scale recycling of isotopically fractionated surface materials back into the Martian mantle. The cumulative δ26Mg value of Martian samples, which are not influenced by late-stage alteration processes and/or crust-mantle interactions, is - 0.271 ± 0.040 ‰ (2SD) and is considered to reflect δ26Mg value of the Bulk Silicate Mars. This value is robust taking into account the range of lithologies involved in this estimate. It also attests to the lack of the Mg isotope variability reported for the inner Solar System bodies at current

Isotopic evolution of Mauna Loa volcano

International Nuclear Information System (INIS)

Kurz, M.D.; Kammer, D.P.

1991-01-01

In an effort to understand the temporal helium isotopic variations in Mauna Loa volcano, we have measured helium, strontium and lead isotopes in a suite of Mauna Loa lavas that span most of the subaerial eruptive history of the volcano. The lavas range in age from historical flows to Ninole basalt which are thought to be several hundred thousand years old. Most of the samples younger than 30 ka in age (Kau Basalt) are radiocarbon-dated flows, while the samples older than 30 ka are stratigraphically controlled (Kahuku and Ninole Basalt). The data reveal a striking change in the geochemistry of the lavas approximately 10 ka before present. The lavas older than 10 ka are characterized by high 3 He/ 4 He (≅ 16-20 times atmospheric), higher 206 Pb/ 204 Pb (≅ 18.2), and lower 87 Sr/ 86 Sr(≅ 0.70365) ratios than the younger Kau samples (having He, Pb and Sr ratios of approximately 8.5 x atmospheric, 18.1 and 0.70390, respectively). The historical lavas are distinct in having intermediate Sr and Pb isotopic compositions with 3 He/ 4 He ratios similar to the other young Kau basalt (≅ 8.5 x atmospheric). The isotopic variations are on a shorter time scale (100 to 10,000 years) than has previously been observed for Hawaiian volcanoes, and demonstrate the importance of geochronology and stratigraphy to geochemical studies. The data show consistency between all three isotope systems, which suggests that the variations are not related to magma chamber degassing processes, and that helium is not decoupled from the other isotopes. However, the complex temporal evolution suggests that three distinct mantle sources are required to explain the isotopic data. Most of the Mauna Loa isotopic variations could be explained by mixing between a plume type source, similar to Loihi, and an asthenospheric source with helium isotopic composition close to MORB and elevated Sr isotopic values. (orig./WL)

Isotopes in hydrology of ground water

International Nuclear Information System (INIS)

Rodriguez, N.; C, O.

1996-01-01

Fundamental concepts on Radioactivity, Isotopes, Radioisotopes, Law of Nuclear Decay (Middle Life concept), Radioactivity units, Types of radiation, Absorption and dispersion of both Alfa and Beta particles and both gamma and X-rays attenuation are presented. A description on Environmental Isotopes (those that are presented in natural form in the environment and those that can't be controlled by the humans), both stables and unstable (radioisotopes) isotopes is made. Isotope hydrology applications in surface water investigations as: Stream flow measurements and Atmosphere - surface waters interrelationship is described. With relation to the groundwater investigations, different applications of the isotope hydrology, its theoretical base and its methodology are presented to each one of the substrates as: Unsaturated zone (soil cape), Saturated zone (aquifer cape), Surface waters - ground waters interrelationship (infiltration and recharge) and to hydrologic balance

Isotopic study of Karst water

International Nuclear Information System (INIS)

Leskovsek-Sefman, H.

1985-01-01

Measurement of the isotopic composition of water formed part of an extended investigation of the water drainage system in the Slovenian Karst. These studies were planned to complement geological and speleological investigations which are already being performed in this area, with the knowledge of the mechanism of changes in the isotopic composition of water in the natural environment on some smaller locations, Planina cave near Postojna where the vertical percolation of meteoric water through the karstified carbonate ceiling was studied and the water catchment areas of some small rivers, Ljubljanica, Rizana and Idrijca. Mass spectrometric investigations of the isotopic composition of some elements ( 18 O, D, 13 C and T) in water and in dissolved carbonates, as well as the isotopic composition of 18 O and 13 C in cave carbonates were performed. The results allow to conclude that the waters in karst aquifers in spite of producing the homogenisation to a great extent, qualitative determination of the retention time and of the prevailing sources for some springs and surface and underground water flows is nevertheless possible. The isotopic composition of 18 O in water and of 18 O and 13 C in dissolved carbonates depends on climatic conditions and on denudation processes. The investigation of cave carbonates revealed that they have different isotopic compositions of 18 O and 13 C because of different locations and also different ages

Isotope separation apparatus and method

International Nuclear Information System (INIS)

Feldman, B. J.

1985-01-01

The invention relates to an improved method and apparatus for laser isotope separation by photodeflection. A molecular beam comprising at least two isotopes to be separated intersects, preferably substantially perpendicular to one broad side of the molecular beam, with a laser beam traveling in a first direction. The laser beam is reflected back through the molecular beam, preferably in a second direction essentially opposite to the first direction. Because the molecules in the beam occupy various degenerate energy levels, if the laser beam comprises chirped pulses comprising selected wavelengths, the laser beam will very efficiently excite substantially all unexcited molecules and will cause stimulated emission of substantially all excited molecules of a selected one of the isotopes in the beam which such pulses encounter. Excitation caused by first direction chirped pulses moves molecules of the isotope excited thereby in the first direction. Stimulated emission of excited molecules of the isotope is brought about by returning chirped pulses traveling in the second direction. Stimulated emission moves emitting molecules in a direction opposite to the photon emitted. Because emitted photons travel in the second direction, emitting molecules move in the first direction. Substantial molecular movement of essentially all the molecules containing the one isotope is accomplished by a large number of chirped pulse-molecule interactions. A beam corer collects the molecules in the resulting enriched divergent portions of the beam

Superdeformation in Pb isotopes

International Nuclear Information System (INIS)

Naz, Tabassum; Ahmad, Shakeb

2017-01-01

The Relatvistic Hartree-Bogoliubov (RHB) theory is used to explore the structure of superdeformed (SD) 190,212 Pb isotopes using the non-linear NL3* and density dependent (DD-ME2, DD-PC1) interactions. We have studied the the excitation energy, the potential depth and the deformation of these Pb isotopes

Isotope and chemical tracers in groundwater hydrology

International Nuclear Information System (INIS)

Kendall, C.; Stewart, M.K.; Morgenstern, U.; Trompetter, V.

1999-01-01

The course sessions cover: session 1, Fundamentals of stable and radioactive isotopes; session 2, Stable oxygen and hydrogen isotopes in hydrology: background, examples, sampling strategy; session 3, Catchment studies using oxygen and hydrogen isotopes: background - the hydrologic water balance, evapotranspiration - the lion's share, runoff generation - new water/old water fractions, groundwater recharge - the crumbs; session 4, Isotopes in catchment hydrology: survey of applications, future developments; session 5, Applications of tritium in hydrology: background and measurement, interpretation, examples; session 6, Case studies using mixing models: Hutt Valley groundwater system, an extended mixing model for simulating tracer transport in the unsaturated zone; session 7, Groundwater dating using CFC concentrations: background, sampling and measurement, use and applications; session 8, Groundwater dating with carbon-14: background, sampling and measurement, use and applications; session 9, NZ case studies: Tauranga warm springs, North Canterbury Plains groundwater; session 10, Stable carbon and nitrogen isotopes: background and examples, biological applications of C-N-S isotopes; session 11, New developments in isotope hydrology: gas isotopes, compound specific applications, age dating of sediments etc; session 12, NZ case studies: North Canterbury Plains groundwater (continued), Waimea Plains groundwater. (author). refs., figs

Iron isotopic systematics of oceanic basalts

Science.gov (United States)

Teng, Fang-Zhen; Dauphas, Nicolas; Huang, Shichun; Marty, Bernard

2013-04-01

The iron isotopic compositions of 93 well-characterized basalts from geochemically and geologically diverse mid-ocean ridge segments, oceanic islands and back arc basins were measured. Forty-three MORBs have homogeneous Fe isotopic composition, with δ56Fe ranging from +0.07‰ to +0.14‰ and an average of +0.105 ± 0.006‰ (2SD/√n, n = 43, MSWD = 1.9). Three back arc basin basalts have similar δ56Fe to MORBs. By contrast, OIBs are slightly heterogeneous with δ56Fe ranging from +0.05‰ to +0.14‰ in samples from Koolau and Loihi, Hawaii, and from +0.09‰ to +0.18‰ in samples from the Society Islands and Cook-Austral chain, French Polynesia. Overall, oceanic basalts are isotopically heavier than mantle peridotite and pyroxenite xenoliths, reflecting Fe isotope fractionation during partial melting of the mantle. Iron isotopic variations in OIBs mainly reflect Fe isotope fractionation during fractional crystallization of olivine and pyroxene, enhanced by source heterogeneity in Koolau samples.

Stable isotope analysis in primatology: a critical review.

Science.gov (United States)

Sandberg, Paul A; Loudon, James E; Sponheimer, Matt

2012-11-01

Stable isotope analysis has become an important tool in ecology over the last 25 years. A wealth of ecological information is stored in animal tissues in the relative abundances of the stable isotopes of several elements, particularly carbon and nitrogen, because these isotopes navigate through ecological processes in predictable ways. Stable carbon and nitrogen isotopes have been measured in most primate taxonomic groups and have yielded information about dietary content, dietary variability, and habitat use. Stable isotopes have recently proven useful for addressing more fine-grained questions about niche dynamics and anthropogenic effects on feeding ecology. Here, we discuss stable carbon and nitrogen isotope systematics and critically review the published stable carbon and nitrogen isotope data for modern primates with a focus on the problems and prospects for future stable isotope applications in primatology. © 2012 Wiley Periodicals, Inc.

Stable isotope research pool inventory

International Nuclear Information System (INIS)

1982-01-01

This report contains a listing of electromagnetically separated stable isotopes which are available for distribution within the United States for nondestructive research use from the Oak Ridge National Laboratory on a loan basis. This inventory includes all samples of stable isotopes in the Material Research Collection and does not designate whether a sample is out on loan or in reprocessing. For some of the high abundance naturally occurring isotopes, larger amounts can be made available; for example, Ca-40 and Fe-56

Electrochemical hydrogen isotope sensor based on solid electrolytes

International Nuclear Information System (INIS)

Matsumoto, Hiroshige; Hayashi, Hiroyuki; Iwahara, Hiroyasu

2002-01-01

An electrochemical sensor of hydrogen isotopes based on solid electrolytes for determining the hydrogen isotope ratios and/or total hydrogen pressures in gases has been developed. This paper describes the methodology of the hydrogen isotope sensing together with experimental results. When hydrogen isotope gases are introduced to an electrochemical cell using a proton-conducting electrolyte (hydrogen isotope cell), the electromotive force (EMF) of the cell agrees with that theoretically estimated. The EMF signals can be used for the determination of the hydrogen isotope ratio in gases if the total hydrogen pressure is predetermined. By supplementary use of an oxide ion conductor cell, both the ratio and total pressure of the hydrogen isotopes can be simultaneously determined. (author)

Isotopic anomalies - chemical memory of Galactic evolution

International Nuclear Information System (INIS)

Clayton, D.D.

1988-01-01

New mechanisms for the chemical memory of isotopic anomalies are proposed which are based on the temporal change during the chemical evolution of the Galaxy of the isotopic composition of the mean ejecta from stars. Because of the differing temporal evolution of primary and secondary products of nucleosynthesis, the isotopic composition of the bulk interstellar medium changes approximately linearly with time, and thus any dust component having an age different from that of average dust will be isotopically anomalous. Special attention is given to C, O, Mg, Si, and isotopically heavy average-stellar condensates of SiC. 20 references

Isotope exchange reactions in hydrogen mixtures

International Nuclear Information System (INIS)

Czaplinski, W.; Gula, A.; Kravtsov, A.; Mikhailov, A.; Popov, N.

1990-12-01

The rates of isotopic exchange for the excited states of muonic hydrogen are calculated as functions of collision energy. Ground state population q 1s for different collision energies, target densities and isotope concentrations is obtained. It is shown that for principal quantum numbers n > 5 the isotopic exchange still considerably influences the value of q 1s . (author)

Dynamical symmetry breaking in barium isotopes

International Nuclear Information System (INIS)

Rawat, Bir Singh; Chattopadhyay, P.K.

1997-01-01

The isotopes of Xe with mass numbers 124, 126, 128, 130 and the isotopes of barium with mass numbers 128, 130, 132, 134 were shown to correspond to the O(6) dynamical symmetry of IBM. In the investigation of the dynamical symmetry breaking in this region, the barium isotopes for departures from O(6) symmetry have been studied

Isotopes in day to day life

Science.gov (United States)

1984-06-01

Developments are reported in the use of isotopic labeling and isotope irradiation in agriculture, medical science, hydrology, geochemistry, geophysics, environment pollution detection, and industries. Radioisotope instruments are described as well as techniques for gamma radiography, neutron radiography, and autoradiography. Isotope dating in geology and archaeology is covered. Basic scientific research topics in various areas are listed.

Stable isotope separation by thermal diffusion

International Nuclear Information System (INIS)

Vasaru, Gheorghe

2001-01-01

Thermal diffusion in both gaseous and liquid phase has been subject of extensive experimental and theoretical investigations, especially after the invention of K. Clusius and G. Dickel of the thermal diffusion column, sixty three years ago. This paper gives a brief overview of the most important research and developments performed during the time at the National Institute for Research and Development for Isotopic and Molecular Technology (ITIM) at Cluj - Napoca, Romania in the field of separation of stable isotopes by thermal diffusion. An retrospective analysis of the research and results concerning isotope separation by thermal diffusion entails the following conclusions: - thermal diffusion is an adequate method for hydrogen isotope separation (deuterium and tritium) and for noble gas isotope separation (He, Ne, Ar, Kr, Xe); - thermal diffusion is attractive also for 13 C enrichment using methane as raw material for separation, when annual yields of up to 100 g are envisaged; - lately, the thermal diffusion appears to be chosen as a final enrichment step for 17 O. An obvious advantage of this method is its non-specificity, i.e. the implied equipment can be utilized for isotope separation of other chemical elements too. Having in view the low investment costs for thermal diffusion cascades the method appears economically attractive for obtaining low-scale, laboratory isotope production. The paper has the following content: 1. The principle of method; 2. The method's application; 3. Research in the field of thermal diffusion at ITIM; 4. Thermal diffusion cascades for N, C, Ne, Ar and Kr isotope separation; 5. Conclusion

Multiple stable isotope fronts during non-isothermal fluid flow

Science.gov (United States)

Fekete, Szandra; Weis, Philipp; Scott, Samuel; Driesner, Thomas

2018-02-01

Stable isotope signatures of oxygen, hydrogen and other elements in minerals from hydrothermal veins and metasomatized host rocks are widely used to investigate fluid sources and paths. Previous theoretical studies mostly focused on analyzing stable isotope fronts developing during single-phase, isothermal fluid flow. In this study, numerical simulations were performed to assess how temperature changes, transport phenomena, kinetic vs. equilibrium isotope exchange, and isotopic source signals determine mineral oxygen isotopic compositions during fluid-rock interaction. The simulations focus on one-dimensional scenarios, with non-isothermal single- and two-phase fluid flow, and include the effects of quartz precipitation and dissolution. If isotope exchange between fluid and mineral is fast, a previously unrecognized, significant enrichment in heavy oxygen isotopes of fluids and minerals occurs at the thermal front. The maximum enrichment depends on the initial isotopic composition of fluid and mineral, the fluid-rock ratio and the maximum change in temperature, but is independent of the isotopic composition of the incoming fluid. This thermally induced isotope front propagates faster than the signal related to the initial isotopic composition of the incoming fluid, which forms a trailing front behind the zone of transient heavy oxygen isotope enrichment. Temperature-dependent kinetic rates of isotope exchange between fluid and rock strongly influence the degree of enrichment at the thermal front. In systems where initial isotope values of fluids and rocks are far from equilibrium and isotope fractionation is controlled by kinetics, the temperature increase accelerates the approach of the fluid to equilibrium conditions with the host rock. Consequently, the increase at the thermal front can be less dominant and can even generate fluid values below the initial isotopic composition of the input fluid. As kinetics limit the degree of isotope exchange, a third front may

Transient competitive complexation in biological kinetic isotope fractionation explains nonsteady isotopic effects: Theory and application to denitrification in soils

Science.gov (United States)

Maggi, Federico; Riley, William J.

2009-12-01

The theoretical formulation of biological kinetic isotope fractionation often assumes first-order or Michaelis-Menten kinetics, the latter solved under the quasi-steady state assumption. Both formulations lead to a constant isotope fractionation factor, therefore they may return incorrect estimations of isotopic effects and misleading interpretations of isotopic signatures when fractionation is not a steady process. We have analyzed the isotopic signature of denitrification in biogeochemical soil systems by Menyailo and Hungate (2006) in which high and variable 15N-N2O enrichment during N2O production and inverse isotope fractionation during N2O consumption could not be explained with first-order kinetics and the Rayleigh equation, or with Michaelis-Menten kinetics. When Michaelis-Menten kinetics were coupled to Monod kinetics to describe biomass and enzyme dynamics, and the quasi-steady state assumption was relaxed, transient Michaelis-Menten-Monod kinetics accurately reproduced the observed concentrations, and variable and inverse isotope fractionations. These results imply a substantial revision in modeling isotopic effects, suggesting that steady state kinetics such as first-order, Rayleigh, and classic Michaelis-Menten kinetics should be superseded by transient kinetics in conjunction with biomass and enzyme dynamics.

Forensic Stable Isotope Biogeochemistry

Science.gov (United States)

Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

2016-06-01

Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

Actinide isotopic analysis systems

International Nuclear Information System (INIS)

Koenig, Z.M.; Ruhter, W.D.; Gunnink, R.

1990-01-01

This manual provides instructions and procedures for using the Lawrence Livermore National Laboratory's two-detector actinide isotope analysis system to measure plutonium samples with other possible actinides (including uranium, americium, and neptunium) by gamma-ray spectrometry. The computer program that controls the system and analyzes the gamma-ray spectral data is driven by a menu of one-, two-, or three-letter options chosen by the operator. Provided in this manual are descriptions of these options and their functions, plus detailed instructions (operator dialog) for choosing among the options. Also provided are general instructions for calibrating the actinide isotropic analysis system and for monitoring its performance. The inventory measurement of a sample's total plutonium and other actinides content is determined by two nondestructive measurements. One is a calorimetry measurement of the sample's heat or power output, and the other is a gamma-ray spectrometry measurement of its relative isotopic abundances. The isotopic measurements needed to interpret the observed calorimetric power measurement are the relative abundances of various plutonium and uranium isotopes and americium-241. The actinide analysis system carries out these measurements. 8 figs

Nickel distribution and isotopic fractionation in a Brazilian lateritic regolith: Coupling Ni isotopes and Ni K-edge XANES

Science.gov (United States)

Ratié, G.; Garnier, J.; Calmels, D.; Vantelon, D.; Guimarães, E.; Monvoisin, G.; Nouet, J.; Ponzevera, E.; Quantin, C.

2018-06-01

Ultramafic (UM) rocks are known to be nickel (Ni) rich and to weather quickly, which makes them a good candidate to look at the Ni isotope systematics during weathering processes at the Earth's surface. The present study aims at identifying the Ni solid speciation and discussing the weathering processes that produce Ni isotope fractionation in two deep laterite profiles under tropical conditions (Barro Alto, Goiás State, Brazil). While phyllosilicates and to a lower extent goethite are the main Ni-bearing phases in the saprolitic part of the profile, iron (Fe) oxides dominate the Ni budget in the lateritic unit. Nickel isotopic composition (δ60Ni values) has been measured in each unit of the regolith, i.e., rock, saprock, saprolite and laterite (n = 52). δ60Ni varies widely within the two laterite profiles, from -0.10 ± 0.05‰ to 1.43 ± 0.05‰, showing that significant Ni isotope fractionation occurs during the weathering of UM rocks. Overall, our results show that during weathering, the solid phase is depleted in heavy Ni isotopes due to the preferential sorption and incorporation of light Ni isotopes into Fe oxides; the same mechanisms likely apply to the incorporation of Ni into phyllosilicates (type 2:1). However, an isotopically heavy Ni pool is observed in the solid phase at the bottom of the saprolitic unit. This feature can be explained by two hypotheses that are not mutually exclusive: (i) a depletion in light Ni isotopes during the first stage of weathering due to the preferential dissolution of light Ni-containing minerals, and (ii) the sorption or incorporation of isotopically heavy Ni carried by percolating waters (groundwater samples have δ60Ni of 2.20 and 2.27‰), that were enriched in heavy Ni isotopes due to successive weathering processes in the overlying soil and laterite units.

Stable isotope mass spectrometry in petroleum exploration

International Nuclear Information System (INIS)

Mathur, Manju

1997-01-01

The stable isotope mass spectrometry plays an important role to evaluate the stable isotopic composition of hydrocarbons. The isotopic ratios of certain elements in petroleum samples reflect certain characteristics which are useful for petroleum exploration

Isotopic diversity in nebular dust: The distribution of Ti isotopic anomalies in carbonaceous chondrites

International Nuclear Information System (INIS)

Niemeyer, S.

1988-01-01

Average Ti isotopic patterns are derived for each class of carbonaceous chondrite from a chemically characterized suite of whole-rock samples. There is a well-resolved excess of 50 Ti in a subset of CI meteorites. Mean values of the 50 Ti excess for the four classes span a range of only 2 ε-units, with an apparent positive correlation with Al content. Previous evidence for anomalies in chondrules is augmented here by demonstrating that: (1) the more pristine Ca-Al-rich inclusions (CAIs) in Efremovka show the same isotopic pattern as the typical Allende CAI; and, (2) CM and CV matrix carry 50 Ti excesses of about 2 ε-units. The distribution of Ti isotopic anomalies among matrix, chondrules, and CAIs suggests a model in which all three constituents formed from precursor-assemblages in which some chemical memories were still intact; the isotopic differences reflect fractionations among the carrier phases of the different isotopic components. Chondrules formed by a mostly closed-system melting of their precursors, and thus provide a recording of the extent of nebular heterogeneity on the mg-size scale. The larger anomalies in CAIs, compared to matrix and most (but not all) chondrules, are attributed primarily to an open- rather than closed-system processing of the CAI precursors. Precursors of both FUN and normal CAIs experienced an episode of intense processing, perhaps partial melting, that created the FUN characteristics, but for normal CAIs the FUN effects were erased by subsequent isotopic equilibration and exchange

Isotope Exchange in Oxide Catalyst

Science.gov (United States)

Hess, Robert V.; Miller, Irvin M.; Schryer, David R.; Sidney, Barry D.; Wood, George M., Jr.; Hoyt, Ronald F.; Upchurch, Billy T.; Brown, Kenneth G.

1987-01-01

Replacement technique maintains level of CO2/18 in closed-cycle CO2 lasers. High-energy, pulsed CO2 lasers using rare chemical isotopes must be operated in closed cycles to conserve gas. Rare isotopes operated in closed cycles to conserve gas. Rare isotopes as CO2/18 used for improved transmission of laser beam in atmosphere. To maintain laser power, CO2 must be regenerated, and O2 concentration kept below few tenths of percent. Conditions achieved by recombining CO and O2.

Isotopic research in Antarctica

International Nuclear Information System (INIS)

Schuetze, H.

1983-01-01

Since 1978 scientists of the Central Institute of Isotope- and Radiation Research of the Academy of Sciences of the GDR have participated in antarctic research. Substantial results have been achieved in research on isotope ratios, on the dynamics of water resources, on concentration of deuterium in lichens, and on age determination of a mummified seal and a penguin colony

Detecting isotopic ratio outliers

International Nuclear Information System (INIS)

Bayne, C.K.; Smith, D.H.

1985-01-01

An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers. 6 refs., 3 figs., 3 tabs

Wide angle isotope separator

International Nuclear Information System (INIS)

Kantrowitz, A.

1976-01-01

A method and apparatus is described for particle separation. The method uses a wide angle radially expanding vapor of a particle mixture. In particular, selective ionization of one isotope type in the particle mixture is produced in a multichamber separator and the ionized isotope type is accelerated out of the path of the vapor expansion for separate collection

Production Situation and Technology Prospect of Medical Isotopes

Directory of Open Access Journals (Sweden)

GAO Feng;LIN Li;LIU Yu-hao;MA Xing-jun

2016-10-01

Full Text Available The isotope production technology was overviewed, including traditional and newest technology. The current situation of medical isotope production was introduced. The problems faced by isotope supply and demand were analyzed. The future development trend of medical isotopes and technology prospect were put forward. As the most populous country, nuclear medicine develops rapidly, however, domestic isotope mainly relies on imports. The highly productive and relatively safe MIPR is expected to be an effective way to breakthrough the bottleneck of the development of nuclear medicine. Traditional isotope production technologies with reactor can be improved. It's urgent to research and promote new isotope production technologies with reactor. Those technologies which do not depend on reactor will have a bright market prospects.

Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems

Energy Technology Data Exchange (ETDEWEB)

Nimz, G. J., LLNL

1998-06-01

A variety of physical processes affect solute concentrations within catchment waters. The isotopic compositions of the solutes can indicate which processes have determined the observed concentrations. These processes together constitute the physical history of the water. Many solutes in natural waters are derived from the interaction between the water and the rock and/or soil within the system - these are termed `lithogenic` solutes. The isotopic compositions of these solutes provide information regarding rock-water interactions. Many other solutes have their isotopic compositions determined both within and outside of the catchment - i.e., in addition to being derived from catchment rock and soil, they are solutes that are also transported into the catchment. Important members of this group include solutes that have isotopic compositions produced by atomic particle interactions with other nuclides. The source of the atomic particles can be cosmic radiation (producing `cosmogenic` nuclides in the atmosphere and land surface), anthropogenic nuclear reactions (producing `thermonuclear` nuclides), or radioactive and fission decay of naturally-occurring elements, principally {sup 238}U (producing `in-situ` lithogenic nuclides in the deep subsurface). Current language usage often combines all of the atomic particle-produced nuclides under the heading `cosmogenic nuclides`, and for simplicity we will often follow that usage here, although always indicating which variety is being discussed. This paper addresses the processes that affect the lithogenic and cosmogenic solute concentrations in catchment waters, and how the isotopic compositions of the solutes can be used in integrative ways to identify these processes, thereby revealing the physical history of the water within a catchment system. The concept of a `system` is important in catchment hydrology. A catchment is the smallest landscape unit that can both participate in all of the aspects of the hydrologic cycle and

Oxygen isotopic fractionation during bacterial sulfate reduction

Science.gov (United States)

Balci, N.; Turchyn, A. V.; Lyons, T.; Bruchert, V.; Schrag, D. P.; Wall, J.

2006-12-01

Sulfur isotope fractionation during bacterial sulfate reduction (BSR) is understood to depend on a variety of environmental parameters, such as sulfate concentration, temperature, cell specific sulfate reduction rates, and the carbon substrate. What controls oxygen isotope fractionation during BSR is less well understood. Some studies have suggested that carbon substrate is important, whereas others concluded that there is a stoichiometric relationship between the fractionations of sulfur and oxygen during BSR. Studies of oxygen fractionation are complicated by isotopic equilibration between sulfur intermediates, particularly sulfite, and water. This process can modify the isotopic composition of the extracellular sulfate pool (δ18OSO4 ). Given this, the challenge is to distinguish between this isotopic equilibration and fractionations linked to the kinetic effects of the intercellular enzymes and the incorporation of sulfate into the bacterial cell. The δ18OSO4 , in concert with the sulfur isotope composition of sulfate (δ34SSO4), could be a powerful tool for understanding the pathways and environmental controls of BSR in natural systems. We will present δ18OSO4 data measured from batch culture growth of 14 different species of sulfate reducing bacteria for which sulfur isotope data were previously published. A general observation is that δ18OSO4 shows little isotopic change (kinetic effect during BSR and/or equilibration between sulfur intermediates and the isotopically light water (~-5‰) of the growth medium. Our present batch culture data do not allow us to convincingly isolate the magnitude and the controlling parameters of the kinetic isotope effect for oxygen. However, ongoing growth of mutant bacteria missing enzymes critical in the different steps of BSR may assist in this mission.

Absolute isotopic abundances of Ti in meteorites

International Nuclear Information System (INIS)

Niederer, F.R.; Papanastassiou, D.A.; Wasserburg, G.J.

1985-01-01

The absolute isotope abundance of Ti has been determined in Ca-Al-rich inclusions from the Allende and Leoville meteorites and in samples of whole meteorites. The absolute Ti isotope abundances differ by a significant mass dependent isotope fractionation transformation from the previously reported abundances, which were normalized for fractionation using 46 Ti/ 48 Ti. Therefore, the absolute compositions define distinct nucleosynthetic components from those previously identified or reflect the existence of significant mass dependent isotope fractionation in nature. We provide a general formalism for determining the possible isotope compositions of the exotic Ti from the measured composition, for different values of isotope fractionation in nature and for different mixing ratios of the exotic and normal components. The absolute Ti and Ca isotopic compositions still support the correlation of 50 Ti and 48 Ca effects in the FUN inclusions and imply contributions from neutron-rich equilibrium or quasi-equilibrium nucleosynthesis. The present identification of endemic effects at 46 Ti, for the absolute composition, implies a shortfall of an explosive-oxygen component or reflects significant isotope fractionation. Additional nucleosynthetic components are required by 47 Ti and 49 Ti effects. Components are also defined in which 48 Ti is enhanced. Results are given and discussed. (author)

Fishing for isotopes in the Brookhaven Lab Isotope Producer (BLIP) cooling water

Energy Technology Data Exchange (ETDEWEB)

Fitzsimmons, Jonathan [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider Accelerator Dept.

2016-04-29

Be-7 has been used in environmental studies; the isotope is produced during BLIP irradiations and accumulates in the 320 gallons of cooling water. Be-7 has a 53.24 day half-life, so the optimal production/purification time is at the end of the BLIP run season. To purify Be-7 fifteen to twenty gallons of BLIP cooling water are removed and pumped through ion exchange columns that retain Be-7. This labor intensive approach captures ~15 mCi of Be-7, but the solution requires further purification. The method can lead to increased radiation exposure to staff. The ideal way to capture isotopes from large volumes is to reach in to the solution and selectively pull out the desired isotope. It is a lot like fishing.

Method for separating gaseous mixtures of isotopes

International Nuclear Information System (INIS)

Neimann, H.J.; Schuster, E.; Kersting, A.

1976-01-01

A gaseous mixture of isotopes is separated by laser excitation of the isotope mixture with a narrow band of wavelengths, molecularly exciting mainly the isotope to be separated and thereby promoting its reaction with its chemical partner which is excited in a separate chamber. The excited isotopes and the chemical partner are mixed, perhaps in a reaction chamber to which the two excited components are conducted by very short conduits. The improvement of this method is the physical separation of the isotope mixture and its partner during excitation. The reaction between HCl and the mixture of 238 UF 6 and 235 UF 6 is discussed

Uranium isotope separation using styrene cation exchangers

International Nuclear Information System (INIS)

Kahovec, J.

1980-01-01

The separation of 235 U and 238 U isotopes is carried out either by simple isotope exchange in the system uranium-cation exchanger (sulphonated styrene divinylbenzene resin), or by combination of isotope exchange in a uranium-cation exchanger (Dowex 50, Amberlite IR-120) system and a chemical reaction. A review is presented of elution agents used, the degree of cation exchanger cross-linking, columns length, and 235 U enrichment. The results are described of the isotope effect study in a U(IV)-U(VI)-cation exchanger system conducted by Japanese and Romanian authors (isotope exchange kinetics, frontal analysis, reverse (indirect) frontal analysis). (H.S.)

Isotope separation apparatus and method

International Nuclear Information System (INIS)

Cotter, T.P.

1982-01-01

The invention relates to a method and apparatus for laser isotope separation by photodeflection. A molecular beam comprising at least two isotopes to be separated intersects, preferable substantially perpendicular to one broad side of the molecular beam, with a laser beam traveling in a first direction. The laser beam is reflected back through the molecular beam, preferably in a second direction essentially opposite to the first direction. The laser beam comprises pi-pulses of a selected wavelength which excite unexcited molecules, or cause stimulated emission of excited molecules of one of the isotopes. Excitation caused by first direction pi-pulses moves molecules of the isotope excited thereby in the first direction. Stimulated emission of excited molecules of the isotope is brought about by returning pi-pulses traveling in the second direction. Stimulated emission moves emitting molecules in a direction opposite to the photon emitted. Because emitted photons travel in the second direction, emitting molecules move in the first direction. Substantial molecular movement is accomplished by a large number of pi-pulse-molecule interactions. A beam corer collects the molecules in the resulting enriched divergent portions of the beam

Carbon and Oxygen isotopic composition in paleoenvironmental determination

International Nuclear Information System (INIS)

Silva, J.R.M. da.

1978-01-01

This work reports that the carbon and oxygen isotopic composition separate the mollusks from marine environment of the mollusks from continental environment in two groups isotopically different, making the biological control outdone by environment control, in the isotopic fragmentation mechanisms. The patterns from the continental environment are more rich in O 16 than the patterns from marine environments. The C 12 is also more frequent in the mollusks from continental environments. The carbon isotopic composition in paterns from continental environments is situated betwen - 10.31 and - 4,05% and the oxygen isotopic composition is situated between - 6,95 and - 2,41%. To the marine environment patterns the carbon isotopic composition is between - 2,08 and + 2,65% and the oxigen isotopic composition is between - 2,08 and + 0,45%. Was also analysed fossil marine mollusks shells and their isotopic composition permit the formulation of hypothesis about the environment which they lived. (C.D.G.) [pt

Transient competitive complexation in biological kinetic isotope fractionation explains non-steady isotopic effects: Theory and application to denitrification in soils

Energy Technology Data Exchange (ETDEWEB)

Maggi, F.M.; Riley, W.J.

2009-06-01

The theoretical formulation of biological kinetic reactions in isotopic applications often assume first-order or Michaelis-Menten-Monod kinetics under the quasi-steady-state assumption to simplify the system kinetics. However, isotopic e ects have the same order of magnitude as the potential error introduced by these simpli cations. Both formulations lead to a constant fractionation factor which may yield incorrect estimations of the isotopic effect and a misleading interpretation of the isotopic signature of a reaction. We have analyzed the isotopic signature of denitri cation in biogeochemical soil systems by Menyailo and Hungate [2006], where high {sup 15}N{sub 2}O enrichment during N{sub 2}O production and inverse isotope fractionation during N{sub 2}O consumption could not be explained with first-order kinetics and the Rayleigh equation, or with the quasi-steady-state Michaelis-Menten-Monod kinetics. When the quasi-steady-state assumption was relaxed, transient Michaelis-Menten-Monod kinetics accurately reproduced the observations and aided in interpretation of experimental isotopic signatures. These results may imply a substantial revision in using the Rayleigh equation for interpretation of isotopic signatures and in modeling biological kinetic isotope fractionation with first-order kinetics or quasi-steady-state Michaelis-Menten-Monod kinetics.

Biogeochemistry of the stable hydrogen isotopes

International Nuclear Information System (INIS)

Estep, M.F.; Hoering, T.C.

1980-01-01

The fractionation of H isotopes between the water in the growth medium and the organically bonded H from microalgae cultured under conditions, where light intensity and wavelength, temperature, nutrient availability, and the H isotope ratio of the water were controlled, is reproducible and light dependent. All studies were based either on the H isotope ratios of the total organic H or on the lipids, where most of the H is firmly bonded to C. H bonded into other macromolecules, proteins, carbohydrates and nucleic acids, does not exchange with water, when algae are incubated in water enriched with deuterium. Only after the destruction of quaternary H bonds are labile hydrogens in macromolecules free to exchange with water. By growing algae (18 strains), including blue-green algae, green algae and diatoms, in continuous light, the isotope fractionations in photosynthesis were reproducibly -93 to -178 per thousand, depending on the organism tested. This fractionation was not temperature dependent. Microalgae grown in total darkness with an organic substrate did not show the isotope fractionation seen in cells grown in light. In both light- and dark-grown algae, however, additional depletion of deuterium (-30 to -60 per thousand) in cellular organic matter occurs during the metabolism of carbohydrates to form lipids. Plants from several natural populations also fractionated isotopes during photosynthesis by an average of -90 to -110 per thousand. In addition, the organically bonded H in nonsaponifiable lipids was further fractionated by -80 per thousand from that in saponifiable lipids, isolated from two geographically distinct populations of marsh plants. This difference between H isotope ratios of these two groups of lipids provides an endogenous isotopic marker. (author)

Biogeochemistry of the stable hydrogen isotopes

Energy Technology Data Exchange (ETDEWEB)

Estep, M F; Hoering, T C [Carnegie Institution of Washington, DC (USA)

1980-08-01

The fractionation of H isotopes between the water in the growth medium and the organically bonded H from microalgae cultured under conditions, where light intensity and wavelength, temperature, nutrient availability, and the H isotope ratio of the water were controlled, is reproducible and light dependent. All studies were based either on the H isotope ratios of the total organic H or on the lipids, where most of the H is firmly bonded to C. H bonded into other macromolecules, proteins, carbohydrates and nucleic acids, does not exchange with water, when algae are incubated in water enriched with deuterium. Only after the destruction of quaternary H bonds are labile hydrogens in macromolecules free to exchange with water. By growing algae (18 strains), including blue-green algae, green algae and diatoms, in continuous light, the isotope fractionations in photosynthesis were reproducibly -93 to -178 per thousand, depending on the organism tested. This fractionation was not temperature dependent. Microalgae grown in total darkness with an organic substrate did not show the isotope fractionation seen in cells grown in light. In both light- and dark-grown algae, however, additional depletion of deuterium (-30 to -60 per thousand) in cellular organic matter occurs during the metabolism of carbohydrates to form lipids. Plants from several natural populations also fractionated isotopes during photosynthesis by an average of -90 to -110 per thousand. In addition, the organically bonded H in nonsaponifiable lipids was further fractionated by -80 per thousand from that in saponifiable lipids, isolated from two geographically distinct populations of marsh plants. This difference between H isotope ratios of these two groups of lipids provides an endogenous isotopic marker.

Stable isotope genealogy of meteorites

International Nuclear Information System (INIS)

Pillinger, C.T.

1988-01-01

One of the oldest problems in meteoritics is that of taxonomically grouping samples. In recent years the use of isotopes, particularly oxygen isotopes has proved very successful in this respect. Other light-element systematics potentially can perform the same function. For example, nitrogen in iron meteorites, and nitrogen and carbon in ureilites and SNC meteorites. These measurements will serve to extend and augment existing classification schemes and provide clues to the nature of meteorite parent bodies. They can also aid in the recognition of the isotopic signatures relating to inaccessible regions of the Earth. (author)

Advances in laser isotope separation

International Nuclear Information System (INIS)

Herman, I.P.; Bernhardt, A.F.

1988-01-01

The physical and chemical concepts required to understand laser isotope separation are presented and discussed. The numerous successful demonstrations of separating isotopes using lasers are reviewed to 1983. Emphasis is placed on the separation of 235-U from 238-U by multi-step selective ioniation of uranium atomic vapor, and on the separation of D and H and of T from D, by pulsed infrared laser multiple-photon dissociation of fluoroform and chloroform, respectively, because they are among the most successful and important examples of laser isotope separation to date. 161 refs.; 7 figs

Iodine isotopes and radiation safety

International Nuclear Information System (INIS)

Styro, B.; Nedvekajte, T.; Filistovich, V.

1992-01-01

Methods of concentration determination of stable and radioactive iodine isotopes in the Earth's different geospheres are described. Iodine isotopes concentration data, chemical forms and transformations as well as their exchange among separate geospheres of their global biochemical circulation (ocean, atmosphere, lithosphere and biosphere) are presented. Information on iodine isotopes as after-effects of nuclear installations accident (in particular, the Chernobyl accident) is generalized. The book is intended for scientists and practical workers in ecology and radioactivity protection and for a students of physics. 442 refs.; 82 figs.; 36 tabs

Stable isotopes - separation and application

International Nuclear Information System (INIS)

Lockhart, I.M.

1980-01-01

In this review, methods used for the separation of stable isotopes ( 12 C, 13 C, 14 N, 15 N, 16 O, 17 O, 18 O, 34 S) will be described. The synthesis of labelled compounds, techniques for detection and assay, and areas of application will also be discussed. Particular attention will be paid to the isotopes of carbon, nitrogen, and oxygen; to date, sulphur isotopes have only assumed a minor role. The field of deuterium chemistry is too extensive for adequate treatment; it will therefore be essentially excluded. (author)

Field experimentation in isotope-aided studies

International Nuclear Information System (INIS)

Zapata, F.

1990-01-01

Isotopic-aided studies involve the application of isotopically labelled fertilizer as tracers for the quantitative and precise determination of the fate of specific nutrient elements in the soil/plant system. The planning of isotopic-aided studies requires a different approach from that followed in the design of normal fertilizer trials because of the cost and supply of isotopically labelled materials, the use of highly specialized equipment and the need for skillful trained staff in the use of isotope techniques both in the field/greenhouse and the laboratory. This report is intended to highlight the main points to be considered while applying those techniques in the field or greenhouse. It has been well established that nuclear techniques are a powerful tool in agricultural research. One should take advantage of the use of such techniques if the following criteria are met: The isotope method is the only way to solve a particular question or to obtain a specific piece of information. There are other methods available for such a purpose but the nuclear method provides a direct and quick means to obtain the needed information resulting in higher economic return

Chlorine isotope effects from isotope ratio mass spectrometry suggest intramolecular C-Cl bond competition in trichloroethene (TCE) reductive dehalogenation.

Science.gov (United States)

Cretnik, Stefan; Bernstein, Anat; Shouakar-Stash, Orfan; Löffler, Frank; Elsner, Martin

2014-05-20

Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (bio)chemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE) dehalogenation was investigated. Selective biotransformation reactions (i) of tetrachloroethene (PCE) to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii) of TCE to cis-1,2-dichloroethene (cis-DCE) in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were -19.0‰ ± 0.9‰ (PCE) and -12.2‰ ± 1.0‰ (TCE) (95% confidence intervals). Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (-5.0‰ ± 0.1‰) and TCE (-3.6‰ ± 0.2‰). In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by -16.3‰ ± 1.4‰ (standard error)) than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average isotope effect of -2.4‰ ± 0.3‰ and the product chloride an isotope effect of -6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals). A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect). These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition). This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I) or single electron transfer as reductive dehalogenation mechanisms.

Isotope separation using vibrationally excited molecules

International Nuclear Information System (INIS)

Woodroffe, J.A.; Keck, J.C.

1977-01-01

A system for isotope separation or enrichment wherein molecules of a selected isotope type in a flow of molecules of plural isotope types are vibrationally excited and collided with a background gas to provide enhanced diffusivity for the molecules of the selected isotope type permitting their separate collection. The system typically is for the enrichment of uranium using a uranium hexafluoride gas in combination with a noble gas such as argon. The uranium hexafluoride molecules having a specific isotope of uranium are vibrationally excited by laser radiation. The vibrational energy is converted to a translation energy upon collision with a particle of the background gas and the added translation energy enhances the diffusivity of the selected hexafluoride molecules facilitating its condensation on collection surfaces provided for that purpose. This process is periodically interrupted and the cryogenic flow halted to permit evaporation of the collected molecules to provide a distinct, enriched flow

Isotopic ratios in the solar system

International Nuclear Information System (INIS)

1985-01-01

This colloquium is aimed at presentation of isotope ratio measurements in different objects of solar system and surrounding interstellar space and evaluation of what information on composition and structure of primitive solar nebula and on chemical evolution of interstellar space in this part of the galaxy can be deduced from it. Isotope ratio in solar system got from laboratory study of extraterrestrial materials is a subject of this colloquium. Then isotope ratio measured in solar wind, planets and comets. Measurements either are made in-situ by mass spectrometry of ions in solar wind or planetery atmosphere gases either are remote measurements of spectra emitted by giant planets and comets. At last, planetology and astrophysics implications are presented and reviewed. Consraints for solar system formation model can be deduced from isotope ratio measurement. Particularly, isotope anomalies are marks of the processes, which have influenced the primitive solar nebula contraction [fr

Isotope shift studies in gadolinium spectra

International Nuclear Information System (INIS)

Ahmad, S.A.; Saksena, G.D.; Venugopalan, A.

1976-01-01

Isotope shift studies have been carried out in the gadolinium spectrum using a recording Fabry-Perot spectrometer and gadolinium samples enriched in 156 Gd and 160 Gd isotopes. Isotope shifts Δsigma(156-160) have been recorded in 134 lines in the region 3930-4140 A. Some of these lines involve the recently identified even configuration 4f 8 5d6s of Gd I and the newly classified transition 4f 8 6s-4f 8 6p of Gd II. From the isotope shift measurements of lines involving the 4f 8 6s-4f 8 6p transition in Gd II, the isotope shift, ΔT(156-160)=87 mK, has been obtained for the 4f 8 6s configuration. Electronic configurations have been suggested for a number of energy levels and configuration mixing has been pointed out in certain cases. (Auth.)

Multi-element isotope dilution analyses using ICP-MS

International Nuclear Information System (INIS)

Volpe, A.M.

1996-01-01

Presently, 37 elements ranging from light (Li,B) through transition metals, noble, rare earth and heavy elements, to actinides and transuranics (Pu, Am, Cm) are measured by isotope dilution at Lawrence Livermore National Laboratory. Projects range from geological and hydrological to biological. The research goal is to measure accurately many elements present in diverse matrices at trace (ppb) levels using isotope dilution methods. Major advantages of isotope dilution methods are accuracy, elimination of ion intensity calibration, and quantitation for samples that require chemical separation. Accuracy depends on tracer isotope calibration, tracer-sample isotopic equilibration, and appropriate background, isobaric and mass bias corrections. Propagation of isotope ratio error due to improper tracer isotope addition is a major concern with multi-element analyses when abundances vary widely. 11 refs., 3 figs

Expanding the isotopic toolbox: Applications of hydrogen and oxygen stable isotope ratios to food web studies

OpenAIRE

Hannah B Vander Zanden; David X Soto; Gabriel J Bowen; Keith A Hobson; Keith A Hobson

2016-01-01

The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicat...

Expanding the Isotopic Toolbox: Applications of Hydrogen and Oxygen Stable Isotope Ratios to Food Web Studies

OpenAIRE

Vander Zanden, Hannah B.; Soto, David X.; Bowen, Gabriel J.; Hobson, Keith A.

2016-01-01

The measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes in tissues of organisms has formed the foundation of isotopic food web reconstructions, as these values directly reflect assimilated diet. In contrast, stable hydrogen (δ2H) and oxygen (δ18O) isotope measurements have typically been reserved for studies of migratory origin and paleoclimate reconstruction based on systematic relationships between organismal tissue and local environmental water. Recently, innovative applicatio...

Isotope toolbox turns 10

DEFF Research Database (Denmark)

Wenander, Fredrik; Riisager, Karsten

2012-01-01

REX-ISOLDE, one of CERN’s most compact accelerators, has just celebrated its 10th anniversary. The machine’s versatility provides radioactive ion beams across the range of nuclear isotopes.......REX-ISOLDE, one of CERN’s most compact accelerators, has just celebrated its 10th anniversary. The machine’s versatility provides radioactive ion beams across the range of nuclear isotopes....

Magnesium isotopic composition of the mantle

Science.gov (United States)

Teng, F.; Li, W.; Ke, S.; Marty, B.; Huang, S.; Dauphas, N.; Wu, F.; Helz, R. L.

2009-12-01

Studies of Mg isotopic composition of the Earth not only are important for understanding its geochemistry but also can shed light on the accretion history of the Earth as well as the evolution of the Earth-Moon system. However, to date, the Mg isotopic composition of the Earth is still poorly constrained and highly debated. There is uncertainty in the magnitude of Mg isotope fractionation at mantle temperatures and whether the Earth has a chondritic Mg isotopic composition or not. To constrain further the Mg isotopic composition of the mantle and investigate the behavior of Mg isotopes during igneous differentiation, we report >200 high-precision (δ26Mg French Polynesian volcanoes (Society island and Cook Austral chain); 3) olivine grains from Hawaiian volcanoes (Kilauea, Koolau and Loihi) and 4) peridotite xenoliths from Australia, China, France, Tanzania and USA. Global oceanic basalts and peridotite xenoliths have a limited (<0.2 ‰) variation in Mg isotopic composition, with an average δ26Mg = -0.25 relative to DSM3. Olivines from Hawaiian lavas have δ26Mg ranging from -0.43 to +0.03, with most having compositions identical to basalts and peridotites. Therefore, the mantle’s δ26Mg value is estimated to be ~ -0.25 ± 0.1 (2SD), different from that reported by Wiechert and Halliday (2007; δ26Mg = ~ 0) but similar to more recent studies (δ26Mg = -0.27 to -0.33) (Teng et al. 2007; Handler et al. 2009; Yang et al., 2009). Moreover, we suggest the Earth, as represented by the mantle, has a Mg isotopic composition similar to chondrites (δ26Mg = ~-0.33). The need for a model such as that of Wiechert and Halliday (2007) that involves sorting of chondrules and calcium-aluminum-rich inclusions in the proto planetary disc is thus not required to explain the Mg isotopic composition of the Earth.

On a Lie-isotopic theory of gravity

International Nuclear Information System (INIS)

Gasperini, M.

1984-01-01

Starting from the isotopic lifting of the Poincare algebra, a Lie-isotopic theory of gravity is formulated, its physical interpretation is given in terms of a generalized principle of equivalence, and it is shown that a local Lorentz-isotopic symmetry motivates the introduction of a generalized metric-affine geometrical structure. Finally, possible applications of a Lie-isotopic theory to the problem of unifying gravity with internal symmetries, in four and more than four dimensions, are discussed

Isotopic tracing of perchlorate in the environment

Science.gov (United States)

Sturchio, Neil C.; Böhlke, John Karl; Gu, Baohua; Hatzinger, Paul B.; Jackson, W. Andrew; Baskaran, Mark

2012-01-01

Isotopic measurements can be used for tracing the sources and behavior of environmental contaminants. Perchlorate (ClO 4 − ) has been detected widely in groundwater, soils, fertilizers, plants, milk, and human urine since 1997, when improved analytical methods for analyzing ClO 4 −concentration became available for routine use. Perchlorate ingestion poses a risk to human health because of its interference with thyroidal hormone production. Consequently, methods for isotopic analysis of ClO 4 − have been developed and applied to assist evaluation of the origin and migration of this common contaminant. Isotopic data are now available for stable isotopes of oxygen and chlorine, as well as 36Cl isotopic abundances, in ClO 4 − samples from a variety of natural and synthetic sources. These isotopic data provide a basis for distinguishing sources of ClO 4 − found in the environment, and for understanding the origin of natural ClO 4 − . In addition, the isotope effects of microbial ClO 4 − reduction have been measured in laboratory and field experiments, providing a tool for assessing ClO 4 − attenuation in the environment. Isotopic data have been used successfully in some areas for identifying major sources of ClO 4 − contamination in drinking water supplies. Questions about the origin and global biogeochemical cycle of natural ClO 4 − remain to be addressed; such work would benefit from the development of methods for preparation and isotopic analysis of ClO 4 − in samples with low concentrations and complex matrices.

Calcium isotope effects in ion exchange electromigration and calcium isotope analysis by thermo-ionization mass spectrometry

International Nuclear Information System (INIS)

Fujii, Y.; Hoshi, J.; Iwamoto, H.; Okamoto, M.; Kakihana, H.

1985-01-01

Calcium ions were made to electromigrate along a cation exchange membrane. The abundance ratios of the calcium isotopes (Ca-40, 42, 43, 44, 48) in the migrated bands were measured by thermo-ionization mass spectrometry. The lighter isotopes were enriched in the front part of the migrated band. The increments in the isotope abundance ratios were found to be proportional to the mass difference of the isotopes. The observed epsilon-values per unit mass difference (epsilon/ΔM) were 1.26 x 10 -4 (at 20 0 C), 1.85 x 10 -4 (at 25 0 C) and 2.4 x 10 -4 (at 40 0 C). The mass spectrometry was improved by using a low temperature for the evaporation of CaI 2 . (orig.)

Compilation of the Dakota Aquifer Project isotope data and publications: The Isotope Hydrology Program of the Isotope Sciences Division

International Nuclear Information System (INIS)

Davisson, M.L.; Smith, D.K.; Hudson, G.B.; Niemeyer, S.; Macfarlane, P.A.; Whittemore, D.O.

1995-01-01

In FY92 the then Nuclear Chemistry Division embarked on a scientific collaboration with the Kansas Geological Survey (KGS) to characterize with isotope techniques groundwater of the Dakota Formation of Kansas. The Dakota Formation is a Cretaceous-aged marine sandstone hosting potable groundwater in most regions of Kansas whose use will serve to partially offset the severe overdraft problems in the overlying Ogallala Formation. The isotope characterization of the Dakota groundwater has generated data that delineates sources, ages, and subsurface controls on the water quality. Initial interpretations of the data have been published in abstract volumes of (1) the 1993 Geological Society of America National Meeting, (2) the 8th International Conference on Geochronology, Cosmochronology and Isotope Geology, and (3) the 1994 Dakota Aquifer Workshop and Clinic. Copies of all abstracts are included in this brief review. One report will focus on the sources and ages of the groundwater, and the other will focus on the subsurface controls on the natural water quality

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

Broadband non-selective excitation of plutonium isotopes for isotope ratio measurements in resonance ionization mass spectrometry: a theoretical study.

Science.gov (United States)

Sankari, M

2012-10-15

Making isotope ratio measurements with minimum isotope bias has always been a challenging task to mass spectrometrists, especially for the specific case of plutonium, owing to the strategic importance of the element. In order to use resonance ionization mass spectrometry (RIMS) as a tool for isotope ratio measurements, optimization of the various laser parameters and other atomic and system parameters is critical to minimize isotopic biases. Broadband simultaneous non-selective excitation of the isotopes of plutonium in the triple resonance excitation scheme with λ(1) = 420.77 nm, λ(2) = 847.28 nm, and λ(3) = 767.53 nm based on density matrix formalism has been theoretically computed for the determination of isotope ratios. The effects of the various laser parameters and other factors such as the atomization temperature and the dimensions of the atomic beam on the estimation of isotope ratios were studied. The effects of Doppler broadening, and time-dependent excitation parameters such as Rabi frequencies, ionization rate and the effect of non-Lorenztian lineshape have all been incorporated. The average laser powers and bandwidths for the three-excitation steps were evaluated for non-selective excitation. The laser intensity required to saturate the three-excitation steps were studied. The two-dimensional lineshape contour and its features were investigated, while the reversal of peak asymmetry of two-step and two-photon excitation peaks under these conditions is discussed. Optimized powers for the non-selective ionization of the three transitions were calculated as 545 mW, 150 mW and 545 mW and the laser bandwidth for all the three steps was ~20 GHz. The isotopic bias between the resonant and off-resonant isotope under the optimized conditions was no more than 9%, which is better than an earlier reported value. These optimized laser power and bandwidth conditions are better than in the earlier experimental work since these comprehensive calculations yield

Isotopic Changes During Digestion: Protein

Science.gov (United States)

Tuross, N.

2013-12-01

Nutrient and hydrological inputs traverse a complicated route of pH, enzymatic and cellular processes in digestion in higher animals. The end products of digestion are the starting products for biosynthesis that are often used to interpret past life-ways. Using an artificial gut system, the isotopic changes (dD, d18O, d13C and d15N) of protein are documented. Three separate protein sources are subjected to the conditions, chemical and enzymatic, found in the stomach and upper small intestine with only a small shift in the oxygen isotopic composition of the proteins observed. Middle to lower small intestine parameters produced both greater isotopic effects and significantly lower molecular weight products. The role of the gastric enterocyte and the likely involvement of the internal milieu of this cell in the isotopic composition of amino acids that are transported to the liver are reported.

Canada's isotope crisis : what next?

Energy Technology Data Exchange (ETDEWEB)

Nathwani, J.; Wallace, D. (eds.)

2010-07-01

Canada urgently requires a rigorous debate on the strategic options for ensuring a robust, reliable, and affordable supply of radioactive isotopes. Should the debate be confined to how Canada can best develop the necessary technologies solely for our own use or should Canada abandon the idea of producing its own isotope supply and any future aspirations to serve the global market? Canada's Isotope Crisis focuses on the central policy question: do we dare to try to shape the future or do we retreat into silence because we are not prepared to make the necessary investments for the future well-being of Canadians? This volume showcases pointed essays and analysis from members of the academy and individuals who have made contributions to the development of medical isotopes and pioneered their use in medical practice. It also includes commentary from those involved in the production, manufacturing, processing, and distribution of isotopes. Canada's Isotope Crisis is a multi-disciplinary effort that addresses the global dimension of isotope supply and combines expert opinions on the present and past with knowledge of the relevant government agencies and the basis for their decisions at critical junctures.

Deciphering the iron isotope message of the human body

Science.gov (United States)

Walczyk, Thomas; von Blanckenburg, Friedhelm

2005-04-01

Mass-dependent variations in isotopic composition are known since decades for the light elements such as hydrogen, carbon or oxygen. Multicollector-inductively coupled plasma mass spectrometry (MC-ICP-MS) and double-spike thermal ionization mass spectrometry (TIMS) permit us now to resolve small variations in isotopic composition even for the heavier elements such as iron. Recent studies on the iron isotopic composition of human blood and dietary iron sources have shown that lighter iron isotopes are enriched along the food chain and that each individual bears a certain iron isotopic signature in blood. To make use of this finding in biomedical research, underlying mechanisms of isotope fractionation by the human body need to be understood. In this paper available iron isotope data for biological samples are discussed within the context of isotope fractionation concepts and fundamental aspects of human iron metabolism. This includes evaluation of new data for body tissues which show that blood and muscle tissue have a similar iron isotopic composition while heavier iron isotopes are concentrated in the liver. This new observation is in agreement with our earlier hypothesis of a preferential absorption of lighter iron isotopes by the human body. Possible mechanisms for inducing an iron isotope effect at the cellular and molecular level during iron uptake are presented and the potential of iron isotope effects in human blood as a long-term measure of dietary iron absorption is discussed.

Chlorine Isotope Effects from Isotope Ratio Mass Spectrometry Suggest Intramolecular C-Cl Bond Competition in Trichloroethene (TCE Reductive Dehalogenation

Directory of Open Access Journals (Sweden)

Stefan Cretnik

2014-05-01

Full Text Available Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (biochemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE dehalogenation was investigated. Selective biotransformation reactions (i of tetrachloroethene (PCE to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii of TCE to cis-1,2-dichloroethene (cis-DCE in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were −19.0‰ ± 0.9‰ (PCE and −12.2‰ ± 1.0‰ (TCE (95% confidence intervals. Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (−5.0‰ ± 0.1‰ and TCE (−3.6‰ ± 0.2‰. In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by −16.3‰ ± 1.4‰ (standard error than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average isotope effect of −2.4‰ ± 0.3‰ and the product chloride an isotope effect of −6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals. A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect. These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition. This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I or single electron transfer as reductive dehalogenation mechanisms.

Pb isotopic composition of the atmosphere of the Sao Paulo city, Brazil, and isotopic characterization of some pollutant sources

International Nuclear Information System (INIS)

Aily, C.; Babinski, M.; Ruiz, I.R.; Sato, K

2001-01-01

Lead isotopes are known to be good tools for surveying lead origin in atmospheric samples (Chow et al., 1975). Lead has four naturally occurring stable isotopes: 206 Pb, 207 Pb, 208 Pb and 204 Pb. The first three isotopes are end products of radioactive decay chains from 238 U, 235 U and 232 Th, respectively, and the last one is non-radiogenic. Therefore, their abundance and the ratios among the four isotopes gradually change with time. Lead in the atmosphere comes from various sources, such as leaded gasoline, industrial emissions and coal combustion. Thus, lead isotope ratios different from those of the mother rock in the region are often observed in the atmosphere (Tatsumoto and Patterson, 1963). Lead is emitted to the atmosphere in fine particles, which can be transported within air masses for very long distances, e. g. from mid latitude regions to the Artic and Antarctica (Sturges and Barrie, 1989). Lead isotopes have been used to trace the pollutant sources in many cities of the world. However, a systematic study using this methodology has not been done in any Brazilian city. The main purpose of the present work is to characterize the Pb isotope composition in the atmosphere in Sao Paulo city, and suggest the possible pollutant sources. For our study lead isotopes were measured in different samples: aerosols and rainwater which would yield the Pb isotope composition of the atmosphere. Samples of gasoline and ethanol, gutter sweepings, soot from vehicle exhaust pipes, and filters containing particulate material from industrial emissions were also analyzed, since they were considered potential pollutant sources of the atmosphere. In order to obtain the local geogenic Pb isotopic composition we also analyzed rock and K-feldspar samples. Lead concentrations were only determined on aerosols and rainwater samples (au)

Sulfur isotope in nature. Determination of sulfur isotope ratios in coal and petroleum by mass spectrometry

International Nuclear Information System (INIS)

Derda, M.

1999-01-01

Elementary sulfur or in chemical compounds is one of the elements widespread in the earth's crust and biosphere. Its participation in earth's crust amounts to 0.26 % by weight. Measurement of isotope composition of natural samples can deliver many information about origin, creation and transformation ranges of rocks and minerals. Sulfur isotope ratio contained in minerals is variable and for this reason investigation of isotope sulfur composition can deliver useful information about the geochemistry of each component. Therefore in the investigated sample it is necessary to determine not only the content of sulfur but also the isotope composition of each component. Differentiation of contents of sulfur-34 in natural sulfur compounds can reach up to 110 per mile. So large divergences can be explained by a kinetic effect or by bacterial reduction of sulphates. In this report a wide review of the results of investigations of isotope sulfur compositions in coal and petroleum are presented as well as the methods for the preparation of samples for mass spectrometry analysis are proposed. (author)

Laser photochemical separation of hydrogen isotopes

International Nuclear Information System (INIS)

Fowler, M.C.

1979-01-01

A method of separating isotopes of hydrogen utilizing isotopically selective photodissociation of organic acid is disclosed. Specifically acetic or formic acid containing compounds of deuterated nd hydrogenated acid is irradiated by radiation having a wavelength in the infrared spectrum between 9.2 to 10.8 microns to produce deuterium hydroxide and deuterium hydride respectively. Maintaining the acid at an elevated temperature significantly improves the yield of isotope separation

Method for isotope separation by photodeflection

International Nuclear Information System (INIS)

Bernhardt, A.F.

1977-01-01

In the method of separating isotopes wherein a desired isotope species is selectively deflected out of a beam of mixed isotopes by irradiating the beam with a directed beam of light of narrowly defined frequency which is selectively absorbed by the desired species, the improvement comprising irradiating the deflected beam with light from other light sources whose frequencies are selected to cause the depopulation of any metastable excited states

Stable isotopes and biomarkers in microbial ecology

NARCIS (Netherlands)

Boschker, H.T.S.; Middelburg, J.J.

2002-01-01

The use of biomarkers in combination with stable isotope analysis is a new approach in microbial ecology and a number of papers on a variety of subjects have appeared. We will first discuss the techniques for analysing stable isotopes in biomarkers, primarily gas chromatography-combustion-isotope

The discovery of isotopes a complete compilation

CERN Document Server

Thoennessen, Michael

2016-01-01

This book describes the exciting discovery of every isotope observed on earth to date, which currently numbers some 3000. For each isotope a short essay highlights the authors of the first publication for the isotope, the laboratory and year where and when the isotope was discovered, as well as details about the production and detection methods used. In controversial cases previously claims are also discussed. At the end a comprehensive table lists all isotopes sorted by elements and a complete list of references. Preliminary versions of these paragraphs have been published over the last few years as separate articles in the journal "Atomic Data and Nuclear Data Tables". The work re-evaluates all assignments judging them with a uniform set of criteria. In addition, the author includes over 100 new isotopes which have been discovered since the articles published. This book is a source of information for researchers as well as enthusiastic laymen alike. From the prepublication review: “The explanations focus ...

Isotope separation by ionic cyclotron resonance

International Nuclear Information System (INIS)

Compant La Fontaine, A.; Gil, C.; Louvet, P.

1986-10-01

The principle of the process of isotopic separation by ionic cyclotron resonance is explained succinctly. The theoretical calculation of the isotopic effect is given as functions of the electric and magnetic fields in the frame of single particle approximation and of plasma collective theory. Then, the main parts of the demonstration device which is in operation at the CEA, are described here: the supraconducting magnetic field, the used diagnostics, the principle of the source and the collecting apparatus. Some experimental results are given for chromium. The application of the process to ponderal separation of metal isotopes, as chromium, nickel and molybdenum is discussed in view of production of medical, structural and irradiation isotopes

Biosynthetic effects on the stable carbon isotopic compositions of agal lipids: Implications for deciphering the carbon isotopic biomarker record

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Schouten, S.; Klein Breteler, W.C.M.; Blokker, P.; Schogt, N.; Rijpstra, W.I.C.; Grice, K.; Baas, M.

1998-01-01

Thirteen species of algae covering an extensive range of classes were cultured and stable carbon isotopic compositions of their lipids were analysed in order to assess carbon isotopic fractionation effects during their biosynthesis. The fatty acids were found to have similar stable carbon isotopic

Basic methods of isotope analysis

International Nuclear Information System (INIS)

Ochkin, A.V.; Rozenkevich, M.B.

2000-01-01

The bases of the most applied methods of the isotope analysis are briefly presented. The possibilities and analytical characteristics of the mass-spectrometric, spectral, radiochemical and special methods of the isotope analysis, including application of the magnetic resonance, chromatography and refractometry, are considered [ru

Temporal variations of isotopes in arid rain storms

International Nuclear Information System (INIS)

Adar, E.M.; Dodi, A.; Geyh, M.A.; Yair, A.

1999-01-01

The distribution of isotopes in rainfall has long been used to elaborate on hydrological systems. Both isotopic composition of stable isotopes (oxygen-18 and deuterium) and tritium content are used to illuminate on sources of groundwater recharge and as tracers upon which groundwater fluxes are assessed. As runoff is concerned, stable isotopes have been used to identify flow paths and the precise location of the rain storm which produced the floods. Analyses of stable isotopes in arid storms in the Negev desert revealed clear discrepancy between the spatial isotopic composition in floods versus the spatial and temporal isotopic composition in rainfall. In addition, simple water balance revealed that the entire flood volume is equivalent to a very small portion of the rain storm, suggesting that a specific flood is produced by a very short and intensive portion of the rainfall. Therefore, knowledge of the weighted isotopic average of a rainfall can not serve as an adequate input function for modeling of desert floods. Since in arid environment, floods are considered as major source of groundwater recharge it also can not be used as input function for modeling of groundwater systems. This paper summarizes detailed isotopic study of short segments (∼2 mm each) of desert rainstorms as sampled in the Negev desert, Israel

Magnesium isotopic composition of the Earth and chondrites

Science.gov (United States)

Teng, Fang-Zhen; Li, Wang-Ye; Ke, Shan; Marty, Bernard; Dauphas, Nicolas; Huang, Shichun; Wu, Fu-Yuan; Pourmand, Ali

2010-07-01

To constrain further the Mg isotopic composition of the Earth and chondrites, and investigate the behavior of Mg isotopes during planetary formation and magmatic processes, we report high-precision (±0.06‰ on δ 25Mg and ±0.07‰ on δ 26Mg, 2SD) analyses of Mg isotopes for (1) 47 mid-ocean ridge basalts covering global major ridge segments and spanning a broad range in latitudes, geochemical and radiogenic isotopic compositions; (2) 63 ocean island basalts from Hawaii (Kilauea, Koolau and Loihi) and French Polynesia (Society Island and Cook-Austral chain); (3) 29 peridotite xenoliths from Australia, China, France, Tanzania and USA; and (4) 38 carbonaceous, ordinary and enstatite chondrites including 9 chondrite groups (CI, CM, CO, CV, L, LL, H, EH and EL). Oceanic basalts and peridotite xenoliths have similar Mg isotopic compositions, with average values of δ 25Mg = -0.13 ± 0.05 (2SD) and δ 26Mg = -0.26 ± 0.07 (2SD) for global oceanic basalts ( n = 110) and δ 25Mg = -0.13 ± 0.03 (2SD) and δ 26Mg = -0.25 ± 0.04 (2SD) for global peridotite xenoliths ( n = 29). The identical Mg isotopic compositions in oceanic basalts and peridotites suggest that equilibrium Mg isotope fractionation during partial melting of peridotite mantle and magmatic differentiation of basaltic magma is negligible. Thirty-eight chondrites have indistinguishable Mg isotopic compositions, with δ 25Mg = -0.15 ± 0.04 (2SD) and δ 26Mg = -0.28 ± 0.06 (2SD). The constancy of Mg isotopic compositions in all major types of chondrites suggest that primary and secondary processes that affected the chemical and oxygen isotopic compositions of chondrites did not significantly fractionate Mg isotopes. Collectively, the Mg isotopic composition of the Earth's mantle, based on oceanic basalts and peridotites, is estimated to be -0.13 ± 0.04 for δ 25Mg and -0.25 ± 0.07 for δ 26Mg (2SD, n = 139). The Mg isotopic composition of the Earth, as represented by the mantle, is similar to chondrites

SAIL--stereo-array isotope labeling.

Science.gov (United States)

Kainosho, Masatsune; Güntert, Peter

2009-11-01

Optimal stereospecific and regiospecific labeling of proteins with stable isotopes enhances the nuclear magnetic resonance (NMR) method for the determination of the three-dimensional protein structures in solution. Stereo-array isotope labeling (SAIL) offers sharpened lines, spectral simplification without loss of information and the ability to rapidly collect and automatically evaluate the structural restraints required to solve a high-quality solution structure for proteins up to twice as large as before. This review gives an overview of stable isotope labeling methods for NMR spectroscopy with proteins and provides an in-depth treatment of the SAIL technology.

Neodymium isotopic variations in seawater

Science.gov (United States)

Piepgras, D. J.; Wasserburg, G. J.

1980-01-01

Direct measurement of the isotopic composition of Nd in the Atlantic agree with the Nd content in ferromanganese sediments and differ from the observed amounts in the Pacific samples. These data indicate the existence of distinctive differences in the isotopic composition of Nd in the waters of major oceans; the average values determined from seawater and ferromanganese sediments are considerably lower than in sources with oceanic mantle affinities showing that the REE in the oceans is dominated by continental sources. The Nd isotopic variations in seawater are applied to relate the residence time of Nd and mixing rates between the oceans.

Iron isotopic fractionation during continental weathering

Energy Technology Data Exchange (ETDEWEB)

Fantle, Matthew S.; DePaolo, Donald J.

2003-10-01

The biological activity on continents and the oxygen content of the atmosphere determine the chemical pathways through which Fe is processed at the Earth's surface. Experiments have shown that the relevant chemical pathways fractionate Fe isotopes. Measurements of soils, streams, and deep-sea clay indicate that the {sup 56}Fe/{sup 54}Fe ratio ({delta}{sup 56}Fe relative to igneous rocks) varies from +1{per_thousand} for weathering residues like soils and clays, to -3{per_thousand} for dissolved Fe in streams. These measurements confirm that weathering processes produce substantial fractionation of Fe isotopes in the modern oxidizing Earth surface environment. The results imply that biologically-mediated processes, which preferentially mobilize light Fe isotopes, are critical to Fe chemistry in weathering environments, and that the {delta}{sup 56}Fe of marine dissolved Fe should be variable and negative. Diagenetic reduction of Fe in marine sediments may also be a significant component of the global Fe isotope cycle. Iron isotopes provide a tracer for the influence of biological activity and oxygen in weathering processes through Earth history. Iron isotopic fractionation during weathering may have been smaller or absent in an oxygen-poor environment such as that of the early Precambrian Earth.

Discovery of the calcium, indium, tin, and platinum isotopes

International Nuclear Information System (INIS)

Amos, S.; Gross, J.L.; Thoennessen, M.

2011-01-01

Currently, twenty-four calcium, thirty-eight indium, thirty-eight tin, and thirty-nine platinum isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented. - Highlights: Documentation of the discovery of all calcium, indium, tin and platinum isotopes. → Summary of author, journal, year, place and country of discovery for each isotope. → Brief description of discovery history of each isotope.

Stable isotope deltas: Tiny, yet robust signatures in nature

Science.gov (United States)

Brand, Willi A.; Coplen, Tyler B.

2012-01-01

Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and paleoclimatology to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including 14C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. 13C, 2H, and 18O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as−25 per mil can be written as−25 mUr (or−2.5 cUr or−0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg ‘units’ are easily included (e.g. either+0.015 ‰ or+15 per meg