Towards the high spin–isospin frontier using isotopically-identified fission fragments

Energy Technology Data Exchange (ETDEWEB)

Navin, A., E-mail: navin@ganil.fr [GANIL, CEA/DSM–CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Rejmund, M.; Schmitt, C. [GANIL, CEA/DSM–CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Bhattacharyya, S. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Lhersonneau, G.; Van Isacker, P. [GANIL, CEA/DSM–CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Caamaño, M. [USC, Universidad de Santiago de Compostela, E-15706 Santiago de Compostela (Spain); Clément, E.; Delaune, O.; Farget, F.; France, G. de; Jacquot, B. [GANIL, CEA/DSM–CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France)

2014-01-20

Measurements of prompt γ rays in coincidence with isotopically-identified fission fragments, produced in collisions of {sup 238}U on a {sup 9}Be target, at an energy around the Coulomb barrier are reported. This technique provides simultaneous access to the spectroscopy of many nuclei, extending to very neutron-rich isotopes and fairly high angular momenta. The structural evolution of the neutron-rich zirconium isotopes is discussed in the light of the present measurements in {sup 105,106}Zr and in the context of the interacting boson model with a global parameterization that includes triaxiality but no shape coexistence.

Towards the high spin–isospin frontier using isotopically-identified fission fragments

International Nuclear Information System (INIS)

Navin, A.; Rejmund, M.; Schmitt, C.; Bhattacharyya, S.; Lhersonneau, G.; Van Isacker, P.; Caamaño, M.; Clément, E.; Delaune, O.; Farget, F.; France, G. de; Jacquot, B.

2014-01-01

Measurements of prompt γ rays in coincidence with isotopically-identified fission fragments, produced in collisions of 238 U on a 9 Be target, at an energy around the Coulomb barrier are reported. This technique provides simultaneous access to the spectroscopy of many nuclei, extending to very neutron-rich isotopes and fairly high angular momenta. The structural evolution of the neutron-rich zirconium isotopes is discussed in the light of the present measurements in 105,106 Zr and in the context of the interacting boson model with a global parameterization that includes triaxiality but no shape coexistence

Comparison of calculated and experimental values of the yields of xenon isotopes in reactions with high-energy protons

International Nuclear Information System (INIS)

Shukolyukov, A.Yu.; Katargin, N.V.; Baishev, I.S.

1989-01-01

Calculations of the cumulative yields of isotopes of Xe have been carried out on the basis of the semi-empirical formula of Silverberg and Tsao for Ba- and Dy-targets and bombarding proton energies in the range 100-1050 MeV. Results are compared with experimental data for the yields of Xe isotopes, and domains of applicability of the semi-empirical formula are determined

Overview of the U.S. Department of Energy's Isotope Programs

Energy Technology Data Exchange (ETDEWEB)

Carty, J.

2004-10-05

This presentation provides an overview of the U.S. Department of Energy's Isotopes Program. The charter of the Isotope Programs covers the production and sale of radioactive and stable isotopes, associated byproducts, surplus materials, and related isotope services.

Candidate processes for diluting the 235U isotope in weapons-capable highly enriched uranium

International Nuclear Information System (INIS)

Snider, J.D.

1996-02-01

The United States Department of Energy (DOE) is evaluating options for rendering its surplus inventories of highly enriched uranium (HEU) incapable of being used to produce nuclear weapons. Weapons-capable HEU was earlier produced by enriching uranium in the fissile 235 U isotope from its natural occurring 0.71 percent isotopic concentration to at least 20 percent isotopic concentration. Now, by diluting its concentration of the fissile 235 U isotope in a uranium blending process, the weapons capability of HEU can be eliminated in a manner that is reversible only through isotope enrichment, and therefore, highly resistant to proliferation. To the extent that can be economically and technically justified, the down-blended uranium product will be made suitable for use as commercial reactor fuel. Such down-blended uranium product can also be disposed of as waste if chemical or isotopic impurities preclude its use as reactor fuel

High-spin research with HERA [High Energy-Resolution Array

International Nuclear Information System (INIS)

Diamond, R.M.

1987-06-01

The topic of this report is high spin research with the High Energy Resolution Array (HERA) at Lawrence Berkeley Laboratory. This is a 21 Ge detector system, the first with bismuth germanate (BGO) Compton suppression. The array is described briefly and some of the results obtained during the past year using this detector facility are discussed. Two types of studies are described: observation of superdeformation in the light Nd isotopes, and rotational damping at high spin and excitation energy in the continuum gamma ray spectrum

Non-collective oblate states in iodine isotopes at high spin

Energy Technology Data Exchange (ETDEWEB)

Paul, E S; Ali, I; Cullen, D M; Fallon, P; Forbes, S A; Hanna, F; Nolan, P J [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Bentley, M A; Bruce, A M; Simpson, J [Daresbury Lab. (United Kingdom); Clark, R M; Regan, P H; Wadsworth, R [York Univ. (United Kingdom). Dept. of Physics; Fossan, D B; Hughes, J R; Lafosse, D R; Vaska, P; Waring, M P [Department of Physics, SUNY at Stony Brook, NY (United States); Liang, Y [Argonne National Lab., IL (United States); Ma, R [Brookhaven National Lab., Upton, NY (United States)

1992-08-01

Competition between single-particle and collective modes of excitation has been observed in the odd-A {sup 113-119}I isotopes at high spin. A maximally-aligned non-collective 43/2{sup -} configuration at {gamma}=+ 60 degrees is seen at similar excitation energies in these nuclei. 7 refs., 4 figs.

Commercial cyclotrons. Part I: Commercial cyclotrons in the energy range 10 30 MeV for isotope production

Science.gov (United States)

Papash, A. I.; Alenitsky, Yu. G.

2008-07-01

A survey of commercial cyclotrons for production of medical and industrial isotopes is presented. Compact isochronous cyclotrons which accelerate negative hydrogen ions in the energy range 10 30 MeV have been widely used over the last 25 years for production of medical isotopes and other applications. Different cyclotron models for the energy range 10 12 MeV with moderate beam intensity are used for production of 11C, 13N, 15O, and 18F isotopes widely applied in positron emission tomography. Commercial cyclotrons with high beam intensity are available on the market for production of most medical and industrial isotopes. In this work, the physical and technical parameters of different models are compared. Possibilities of improving performance and increasing intensity of H- beams up to 2 3 mA are discussed.

High energy particle experiment for the GEOTAIL mission

International Nuclear Information System (INIS)

1989-09-01

The high energy particle experiment for GEOTAIL mission was designed to understand the particle acceleration mechanism, energy flow, boundary dynamics and magnetic reconnection mechanism in the geotail region, solar flare particle acceleration mechanism, the propagation mechanism through interplanetary space, and the origin, lifetime and propagation mechanism of cosmic ray heavy ions. In order to achieve these objectives, particle detectors, burst detectors, medium energy isotope telescopes and a high energy isotope telescope will be placed in the spacecraft which will be launched in 1992 as one of the spacecraft missions in the International Solar Terrestrial Physics program. With these detectors, electrons, protons and helium, carbon, silicon and iron particles will be detected. The characteristics and the main technique used for each instrument to observe high energy particles are summarized. The details of the scientific objectives, the basic principle of particle identification, the electronic system and data processing system, key parameter information, telemetry data formats, preflight and in-flight calibration method and data an analysis plan are described in this report. (K.I.)

Routes for the production of isotopes for PET with high intensity deuteron accelerators

Science.gov (United States)

Arias de Saavedra, F.; Porras, I.; Praena, J.

2018-04-01

Recent advances in accelerator science are opening new possibilities in different fields of physics. In particular, the development of compact linear accelerators that can provide charged particles of low-medium energy (few MeV) with high current (above mA) allows for the study of new possibilities in neutron production and for new routes for the production of radioisotopes. Keeping in mind how radioisotopes are actually produced in dedicated facilities, we have performed a study of alternative reactions to produce PET isotopes induced by low-energy deuterons. We have fitted the EXFOR cross sections data, used the fitted values of the stopping power by Andersen and Ziegler and calculated by numerical integration the production rate of isotopes for charged particles up to 20 MeV. The results for deuterons up to 3 MeV are compared with the ones from cyclotrons, which are able to provide higher energies to the charged projectiles but with lower intensities. Our results indicate that using linear accelerators may be a good alternative for producing PET isotopes, reducing the problem of neutron activation.

Calculation of isotopic mass and energy production by a matrix operator method

International Nuclear Information System (INIS)

Lee, C.E.

1976-08-01

The Volterra method of the multiplicative integral is used to determine the isotopic density, mass, and energy production in linear systems. The solution method, assumptions, and limitations are discussed. The method allows a rapid accurate calculation of the change in isotopic density, mass, and energy production independent of the magnitude of the time steps, production or decay rates, or flux levels

Equation-of-state for fluids at high densities-hydrogen isotope measurements and thermodynamic derivations

International Nuclear Information System (INIS)

Liebenberg, D.H.; Mills, R.L.; Bronson, J.C.

1977-01-01

Hydrogen isotopes play an important role in energy technologies, in particular, the compression to high densities for initiation of controlled thermonuclear fusion energy. At high densities the properties of the compressed hydrogen isotopes depart drastically from ideal thermodynamic predictions. The measurement of accurate data including the author's own recent measurements of n-H 2 and n-D 2 in the range 75 to 300 K and 0.2 to 2.0 GPa (2 to 20 kbar) is reviewed. An equation-of-state of the Benedict type is fit to these data with a double-process least-squares computer program. The results are reviewed and compared with existing data and with a variety of theoretical work reported for fluid hydrogens. A new heuristic correlation is presented for simplicity in predicting volumes and sound velocity at high pressures. 9 figures, 1 table

Development of a system for determination of the 13C/12C isotopic ratio with high spatial resolution

International Nuclear Information System (INIS)

Kristiansson, Per.; Hode, Tomas; Auzelyte, Vaida; Elfman, Mikael; Malmqvist, Klas; Nilsson, Christer; Pallon, Jan; Shariff, Asad; Wegden, Marie

2004-01-01

Stable carbon isotopes play an important role in the interpretation of biological activity, particularly when the fossil record is studied. In combination with morphological and chemical data, isotopic information can be useful in paleontology and astrobiology. In this paper the development of a microanalytical ion beam system for the measurement of the carbon isotope ratio with high spatial resolution and good statistics is presented. The technique used is elastic scattering of alpha particles with an energy of 2.75 MeV. At this energy the 13 C cross-section is enhanced relative to the Rutherford cross-section and while the 12 C cross-section is reduced. The optimisation of the system is described, including sample preparation and the design of the particle detection system for high efficiency combined with good energy resolution. Finally, some results from the initial test run of the system are shown and discussed

Procedure and device for separating isotopes of high mass

International Nuclear Information System (INIS)

Eerkens, J.W.

1977-01-01

The invention refers to isotope separation and to selectively photon-induced energy transfer from an isotope molecule containing the isotope to be separated as well as to a chemical reaction with a reactive agent in order to produce a chemical compound containing atoms of the desired isotope. For example, in the most preferable form of the invention, gaseous UF 6 is contained in a mixture of U 235 F 6 and U 238 F 6 molecules in a reaction chamber. A chemically reactive substance, which for U 235 separation may be gaseous HCl according to the invention, is also introduced into the reaction chamber. (HK) [de

Production and supply of radioisotopes with high-energy particle accelerators current status and future directions

International Nuclear Information System (INIS)

Srivastava, S.C.; Mausner, L.F.

1994-01-01

Although the production of radioisotopes in reactors or in low to medium energy cyclotrons appears to be relatively well established, especially for those isotopes that are routinely used and have a commercial market, certain isotopes can either be made only in high-energy particle accelerators or their production is more cost effective when made this way. These facilities are extremely expensive to build and operate, and isotope production is, in general, either not cost-effective or is in conflict with their primary mandate or missions which involve physics research. Isotope production using high-energy accelerators in the US, therefore, has been only an intermittent and parasitic activity. However, since a number of isotopes produced at higher energies are emerging as being potentially useful for medical and other applications, there is a renewed concern about their availability in a continuous and reliable fashion. In the US, in particular, the various aspects of the prediction and availability of radioisotopes from high-energy accelerators are presently undergoing a detailed scrutiny and review by various scientific and professional organizations as well as the Government. A number of new factors has complicated the supply/demand equation. These include considerations of cost versus needs, reliability factors, mission orientation, research and educational components, and commercial viability. This paper will focus on the present status and projected needs of radioisotope production with high-energy accelerators in the US, and will compare and examine the existing infrastructure in other countries for this purpose

Energy dependence of isotopic spectra from spallation residues

International Nuclear Information System (INIS)

Audouin, L.

2003-09-01

Spallation reactions are collisions between heavy nuclei and light particle with an energy of a few hundreds MeV. The y are considered as a suitable way to create high- flux neutrons sources, which may used for example for the transmutation of nuclear wastes (hybrid reactors). The study of the residues from such reactions is both a way to understand the physics of the spallation and to provide information required for the design of industrial targets. The residues from the spallation of lead by proton at 500 MeV have been measured using the inverse kinematics technique in the FRS (fragments recoil separator). spectrometer from GSI (Barmstadt). This low energy required the use of new technique, for the experimental setup as well as during the analysis. The fragments were identified in-flight, prior to β decay. Complete isotopic distributions are obtained with an accuracy ranging between 10 and 30%. Detailed information on the reaction kinematics are also obtained. Data are in excellent agreement with radio-chemical measurements, and bring new insights about the spallation process. The comparison with data measured on the same system with an incident energy of 1 GeV allows to discuss the influence of the projectile energy on the residues formation. It is concluded that the independence of the shape of the isobaric production cross sections regarding mass and energy of the projectile is preserved at low incident energies. The behaviour of Monte-Carlo codes is discussed with respect to those sets of data. The calculations show an improving agreement with decreasing energy, indicating that high-energy phenomena, for which some common assumptions become questionable, are the main reason for the observed discrepancies. (author)

High Accuracy, High Energy He-Erd Analysis of H,C, and T

International Nuclear Information System (INIS)

Browning, James F.; Langley, Robert A.; Doyle, Barney L.; Banks, James C.; Wampler, William R.

1999-01-01

A new analysis technique using high-energy helium ions for the simultaneous elastic recoil detection of all three hydrogen isotopes in metal hydride systems extending to depths of several microm's is presented. Analysis shows that it is possible to separate each hydrogen isotope in a heavy matrix such as erbium to depths of 5 microm using incident 11.48MeV 4 He 2 ions with a detection system composed of a range foil and ΔE-E telescope detector. Newly measured cross sections for the elastic recoil scattering of 4 He 2 ions from protons and deuterons are presented in the energy range 10 to 11.75 MeV for the laboratory recoil angle of 30degree

Neutron separation energies of Zr isotopes

International Nuclear Information System (INIS)

Gomes, L.C.; Dietzsch, O.

1976-01-01

Q values are reported for (d,t) reactions on all the stable isotopes of zirconium. The neutron separation energies of 94 Zr and 96 Zr differ greatly (by 27.5 and 22.1 keV, respectively) from the values in the 1971 Atomic Mass Evaluation. These results combined with those from other authors seem to indicate that the 1971 values for the masses of 93 Zr and 95 Zr are in error. (orig.) [de

Investigation of mechanisms of production of argon, krypton and xenon isotopes formed in heavy targets by protons with an energy ranging from 0.15 to 24 GeV

International Nuclear Information System (INIS)

Sauvageon, Henri

1981-01-01

As experimental results of the investigation of interactions between high-energy protons and nucleus generally lead to the distinction between four types of reaction mechanisms (spallation, fission, fragmentation and isotope production), this research thesis reports the study of this mechanisms by using the so-called 'thick target - thick collector' experiment and by studying the production of various isotopes of rare gases (argon, krypton, xenon). These isotopes are produced by using platinum, gold, bismuth and thorium targets bombarded by protons with an energy ranging from 0.15 to 24 GeV. The author presents the experimental methods (target preparation and irradiation, rare gas analysis system), reports the analysis of thick target - thick-collector experiments (vector-based representation, path determination, path-curve energy, corrections of experimental data, excitation energy of the intermediate nucleus), presents the experimental results, and discusses their interpretation (two-stage model of high energy nuclear reactions, isotopes produced by spallation and by fission, isotopes produced by deep spallation, representations of mechanisms of fragmentation and deep spallation)

The RaDIATE High-Energy Proton Materials Irradiation Experiment at the Brookhaven Linac Isotope Producer Facility

Energy Technology Data Exchange (ETDEWEB)

Ammigan, Kavin; et al.

2017-05-01

The RaDIATE collaboration (Radiation Damage In Accelerator Target Environments) was founded in 2012 to bring together the high-energy accelerator target and nuclear materials communities to address the challenging issue of radiation damage effects in beam-intercepting materials. Success of current and future high intensity accelerator target facilities requires a fundamental understanding of these effects including measurement of materials property data. Toward this goal, the RaDIATE collaboration organized and carried out a materials irradiation run at the Brookhaven Linac Isotope Producer facility (BLIP). The experiment utilized a 181 MeV proton beam to irradiate several capsules, each containing many candidate material samples for various accelerator components. Materials included various grades/alloys of beryllium, graphite, silicon, iridium, titanium, TZM, CuCrZr, and aluminum. Attainable peak damage from an 8-week irradiation run ranges from 0.03 DPA (Be) to 7 DPA (Ir). Helium production is expected to range from 5 appm/DPA (Ir) to 3,000 appm/DPA (Be). The motivation, experimental parameters, as well as the post-irradiation examination plans of this experiment are described.

Descriptions of carbon isotopes within the energy density functional theory

International Nuclear Information System (INIS)

Ismail, Atef; Cheong, Lee Yen; Yahya, Noorhana; Tammam, M.

2014-01-01

Within the energy density functional (EDF) theory, the structure properties of Carbon isotopes are systematically studied. The shell model calculations are done for both even-A and odd-A nuclei, to study the structure of rich-neutron Carbon isotopes. The EDF theory indicates the single-neutron halo structures in 15 C, 17 C and 19 C, and the two-neutron halo structures in 16 C and 22 C nuclei. It is also found that close to the neutron drip-line, there exist amazing increase in the neutron radii and decrease on the binding energies BE, which are tightly related with the blocking effect and correspondingly the blocking effect plays a significant role in the shell model configurations

Application of hydrogen isotopes and metal hydrides in future energy source

Energy Technology Data Exchange (ETDEWEB)

Guoqiang, Jiang [Sichuan Inst. of Materials and Technology, Chengdu, SC (China)

1994-12-01

The probable application of hydrogen isotopes and metal hydrides to future energy source is reviewed. Starting from existing state of China`s energy source, the importance for developing hydrogen energy and fusion energy is explained. It is suggested that the application investigation of hydrogen energy and hydrogen storage materials should be spurred and encouraged; keeping track of the development on tritium technology for fusion reactor is stressed.

Application of hydrogen isotopes and metal hydrides in future energy source

International Nuclear Information System (INIS)

Jiang Guoqiang

1994-12-01

The probable application of hydrogen isotopes and metal hydrides to future energy source is reviewed. Starting from existing state of China's energy source, the importance for developing hydrogen energy and fusion energy is explained. It is suggested that the application investigation of hydrogen energy and hydrogen storage materials should be spurred and encouraged; keeping track of the development on tritium technology for fusion reactor is stressed

Descriptions of carbon isotopes within the energy density functional theory

Energy Technology Data Exchange (ETDEWEB)

Ismail, Atef [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia and Department of Physics, Al-Azhar University, 71524 Assiut (Egypt); Cheong, Lee Yen; Yahya, Noorhana [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Tammam, M. [Department of Physics, Al-Azhar University, 71524 Assiut (Egypt)

2014-10-24

Within the energy density functional (EDF) theory, the structure properties of Carbon isotopes are systematically studied. The shell model calculations are done for both even-A and odd-A nuclei, to study the structure of rich-neutron Carbon isotopes. The EDF theory indicates the single-neutron halo structures in {sup 15}C, {sup 17}C and {sup 19}C, and the two-neutron halo structures in {sup 16}C and {sup 22}C nuclei. It is also found that close to the neutron drip-line, there exist amazing increase in the neutron radii and decrease on the binding energies BE, which are tightly related with the blocking effect and correspondingly the blocking effect plays a significant role in the shell model configurations.

Experimental determination of one- and two-neutron separation energies for neutron-rich copper isotopes

Science.gov (United States)

Yu, Mian; Wei, Hui-Ling; Song, Yi-Dan; Ma, Chun-Wang

2017-09-01

A method is proposed to determine the one-neutron S n or two-neutron S 2n separation energy of neutron-rich isotopes. Relationships between S n (S 2n) and isotopic cross sections have been deduced from an empirical formula, i.e., the cross section of an isotope exponentially depends on the average binding energy per nucleon B/A. The proposed relationships have been verified using the neutron-rich copper isotopes measured in the 64A MeV 86Kr + 9Be reaction. S n, S 2n, and B/A for the very neutron-rich 77,78,79Cu isotopes are determined from the proposed correlations. It is also proposed that the correlations between S n, S 2n and isotopic cross sections can be used to find the location of neutron drip line isotopes. Supported by Program for Science and Technology Innovation Talents at Universities of Henan Province (13HASTIT046), Natural and Science Foundation in Henan Province (162300410179), Program for the Excellent Youth at Henan Normal University (154100510007) and Y-D Song thanks the support from the Creative Experimental Project of National Undergraduate Students (CEPNU 201510476017)

United States Department of Energy Office of Nuclear Energy, Isotope Production and Distribution Program financial statements, September 30, 1996 and 1995

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-04-01

The charter of the Department of Energy (DOE) Isotope Production and Distribution Program (Isotope Program) covers the production and sale of radioactive and stable isotopes, associated byproducts, surplus materials such as lithium, and related isotope services. Service provided include, but are not limited to, irradiation services, target preparation and processing, source encapsulation and other special preparations, analyses, chemical separations, and leasing of stable isotopes for research purposes. Isotope Program products and services are sold worldwide for use in a wide variety of research, development, biomedical, and industrial applications. This report presents the results of the independent certified public accountants` audit of the Isotope Production and Distribution Program`s (Isotope) financial statements as of September 30, 1996.

Isotope shifts in odd and even energy levels of the neutral and singly ionised gadolinium atom

International Nuclear Information System (INIS)

Ahmad, S.A.; Venugopalan, A.; Saksena, G.D.

1979-01-01

Isotope shift studies in the gadolinium spectra have been extended in the region 4140 to 4535 A. Isotope shift Δσ(156 to 160) have been measured in 315 lines of the neutral and singly ionised gadolinium atom using a recording Fabry-Perot Spectrometer and gadolinium samples enriched in 156 Gd and 160 Gd isotopes. Some of the Gd I lines studied involve transitions from newly identified high odd levels of 4f 8 6s6p, 4f 7 5d6s7s and 4f 7 5d 3 configurations to low even levels of 4f 8 6s 2 and 4f 7 6s 2 6p configurations. Electronic configurations of the energy levels have been discussed on the basis of observed isotope shifts. In some cases assigned configurations have been revised and probable configurations have been suggested. (author)

Isotopic distribution of Rb, In and Cs, produced in interactions of high energy protons, deuterons and alpha particles with Ta nuclei

International Nuclear Information System (INIS)

Avdeev, S.P.; Karnaukhov, V.A.; Korovin, G.Yu.; Kuznetsov, V.D.; Nad', T.; Petrov, L.A.

1982-01-01

The purpose of the paper is to clarify how the isotopical distribution form of deep fissaon products depends on the type of the bombarding particles. Isotopical distributions of Rb, In, Cs, produced at interactions of protons, deuterons ( 8 GeV) and α particles (15.2 GeV) with Ta nuclei are measured by means of the ''off-line'' mass separation. The isotopical distributions are obtained by the experimentally measured yields directly without complex procedure of processing necessary for transition to the charge distribution. It was found that neither the position of the maximum, nor the shape of the curve are changed essentially at variation of the projectile. In all the cases the relative behaviour of the distribution is in a qualitative agreement with the calculations based upon the semiempirical formula by Rudstam. For indium the mesurements are performed also with the proton beam of energy 0.66 GeV. In this case the shape of the isotopic distribution is influenced by the fission process [ru

High Resolution Gamma Ray Analysis of Medical Isotopes

Science.gov (United States)

Chillery, Thomas

2015-10-01

Compton-suppressed high-purity Germanium detectors at the University of Massachusetts Lowell have been used to study medical radioisotopes produced at Brookhaven Linac Isotope Producer (BLIP), in particular isotopes such as Pt-191 used for cancer therapy in patients. The ability to precisely analyze the concentrations of such radio-isotopes is essential for both production facilities such as Brookhaven and consumer hospitals across the U.S. Without accurate knowledge of the quantities and strengths of these isotopes, it is possible for doctors to administer incorrect dosages to patients, thus leading to undesired results. Samples have been produced at Brookhaven and shipped to UML, and the advanced electronics and data acquisition capabilities at UML have been used to extract peak areas in the gamma decay spectra. Levels of Pt isotopes in diluted samples have been quantified, and reaction cross-sections deduced from the irradiation parameters. These provide both cross checks with published work, as well as a rigorous quantitative framework with high quality state-of-the-art detection apparatus in use in the experimental nuclear physics community.

IBFA description of high-spin positive-parity states in Rh isotopes

International Nuclear Information System (INIS)

Bucurescu, D.; Cata, G.; Cutoiu, D.; Constantinescu, G.; Ivascu, M.; Zamfir, N.V.

1985-01-01

Properties of the odd-mass Rh isotopes are investigated in the framework of the interacting boson-fermion approximation (IBFA) model in which the odd proton moves in the 1gsub(9/2) and 2dsub(5/2) orbitals. Lifetimes of some high-spin positive-parity states in 99 Rh obtained by the recoil-distance method with the 88 Sr( 14 N,3n) reaction are also reported. Calculated excitation energies and electromagnetic properties of the high-spin positive-parity states are compared with experiment and an acceptable agreement is obtained. (orig.)

H/D isotope effects in high temperature proton conductors

DEFF Research Database (Denmark)

Bonanos, Nikolaos; Huijser, A.; Poulsen, Finn Willy

2015-01-01

The atomic mass ratio of ca. 2 between deuterium and hydrogen is the highest for any pair of stable isotopes and results in significant and measurable H/D isotope effects in high temperature proton conductors containing these species. This paper discusses H/D isotope effects manifested in O-H/O-D...

Low-energy fission systematics of the fermium isotopes: the transition from mass asymmetry at fermium-254 to symmetry at fermium-259

International Nuclear Information System (INIS)

Hoffman, D.C.

1976-01-01

Recent measurements have shown that 259 Fm gives the highest total kinetic energy release and the most symmetric mass division so far observed for spontaneous fission. These results continue the trends observed previously in the fermium isotopes toward higher total kinetic energies and more symmetric mass division with increasing mass of the fermium isotopes. The transition from asymmetric mass division ( 254 Fm) to highly favored symmetric mass division ( 259 Fm) now appears to have been completed. These features are consistent with the simple postulate that the more neutron-rich fermium isotopes show an increase in the yield of symmetric fragments and in the total kinetic energy because symmetric mass division of fermium (Z = 100) nuclei results in two fragments which have the magic proton number of 50 and are close to the magic neutron number of 82. The proximity of the fragments to the doubly magic configuration seems to have a profound effect on the mass division and total kinetic energy release in fission

Hartree-Fock calculation of nuclear binding energy of sodium isotopes

International Nuclear Information System (INIS)

Campi, X.; Flocard, H.

1975-01-01

Mass spectrometer measurements of the neutron rich sodium isotopes show a sudden increase at 31 Na in the values of the two neutron separation energies. The spherical shell model naturally predicts a sudden decrease at 32 Na after the N=20 shell closure. It is proposed that the explanation for this disagreement lies in the fact that sodium isotopes in this mass region are strongly deformed due to the filling of negative parity orbitals from the 1f(7/2) shell. Hartree-Fock calculations are presented in support of this conjecture [fr

Energy dependence of the absorptive potential for sub-Coulomb energy proton bombardment of zirconium and molybdenum isotopes

International Nuclear Information System (INIS)

Flynn, D.S.; Hershberger, R.L.; Gabbard, F.

1985-01-01

The measured (p,p) and (p,n) excitation functions for /sup 92,94,96/Zr and /sup 95,98,100/Mo were fitted in the energy range 2 3 for all isotopes studied as the proton bombarding energy is increased toward 15 MeV. This result is consistent with results from analyses at higher energies

Production and supply of radioisotopes with high-energy particle accelerators current status and future directions

International Nuclear Information System (INIS)

Srivastava, S.C.; Mausner, L.F.

1994-01-01

Although the production of radioisotopes in reactors or in low to medium energy cyclotrons appears to be relatively well established, certain isotopes can either be made only in high-energy particle accelerators or their production is more cost effective when made this way. These facilities are extremely expensive to build and operate, and isotope production is, in general, either not cost-effective or is in conflict with their primary mandate or missions which involve physics research. Isotope production using high-energy accelerators in the U.S., therefore, has been only an intermittent and parasitic activity. However, since a number of isotopes produced at higher energies are emerging as being potentially useful for medical and other applications, there is a renewed concern about their availability in a continuous and reliable fashion. In the U.S., in particular, the various aspects of the production and availability of radioisotopes from high-energy accelerators are presently undergoing a detailed scrutiny and review by various scientific and professional organizations as well as the Government. A number of new factors has complicated the supply/demand equation. These include considerations of cost versus needs, reliability factors, mission orientation, research and educational components, and commercial viability. This paper will focus on the present status and projected needs of radioisotope production with high-energy accelerators in the U.S., and will compare and examine the existing infrastructure in other countries for this purpose. The nature of the U.S. decisions to address many of the above-mentioned issues and an eventual plan of attack to resolve them are bound to have a world-wide impact in the radioisotope user communities. These will be discussed with a view to evaluating the best possible solutions in order to eliminate the shortage in the future supply of radioisotopes produced in high energy accelerators. (author)

Vibrational energy transfer in hydrogen liquid and its isotopes

International Nuclear Information System (INIS)

Gale, G.M.; Delalande, C.

1978-01-01

The transfer of vibrational energy (V-V) from H 2 to isotopic impurities (HD or D 2 ) has been studied in the liquid state, between 15 and 30 K. The subsequent ralaxation (V-T) of the excited impurity by the H 2 liquid host has also been measured and contrasted with the vibrational relaxation behaviour of pure H 2 and D 2 liquids. The isothermal density dependence of both V-V and V-T transfer has been investigated in the fluid state at 30 K. High density relaxation rates are also compared to the data in the pure gases and to other available gas phase results. Measurements in the solid, near the triple-point temperature, are equally reported for each process studied. (Auth.)

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

System and method for high precision isotope ratio destructive analysis

Science.gov (United States)

Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

2013-07-02

A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

High Flux Isotope Reactor technical specifications

International Nuclear Information System (INIS)

1985-11-01

This report gives technical specifications for the High Flux Isotope Reactor (HFIR) on the following: safety limits and limiting safety system settings; limiting conditions for operation; surveillance requirements; design features; and administrative controls

SU-F-I-56: High-Precision Gamma-Ray Analysis of Medical Isotopes

Energy Technology Data Exchange (ETDEWEB)

Chopra, N; Chillery, T; Chowdhury, P; Lister, C [University of Massachusetts-Lowell, Lowell, MA (United States); McCutchan, E [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY (United States); Smith, C [BLIP Facility, Brookhaven National Laboratory, Upton, NY (United States)

2016-06-15

Purpose: Advanced, time-resolved, Compton-suppressed gamma-ray spectroscopy with germanium detectors is implemented for assaying medical isotopes to study the radioactive decay process leading to a more accurate appraisal of the received dose and treatment planning. Lowell’s Array for Radiological Assay (LARA), a detector array that is comprised of six Compton-suppressed high-purity germanium detectors, is currently under development at UMass-Lowell which combines Compton-suppression and time-and-angle correlations to allow for highly efficient and highly sensitive measurements. Methods: Two isotopes produced Brookhaven Linac Isotope Producer (BLIP) were investigated. {sup 82}Sr which is the parent isotope for producing {sup 82}Rb is often used in cardiac PET. {sup 82}Sr gamma-ray spectrum is dominated by the 511keV photons from positron annihilation which prevent precise measurement of co-produced contaminant isotopes. A second project was to investigate the production of platinum isotopes. Natural platinum was bombarded with protons from 53MeV to 200MeV. The resulting spectrum was complicated due to the large number of stable platinum isotopes in the target, the variety of open reaction channels (p,xn), (p,pxn), (p,axn). Results: By using face-to-face NaI(Tl) counters 90-degrees to the Compton-suppressed germaniums to detect the 511keV photons, a much cleaner and more sensitive measurement of {sup 85}Sr and other contaminants was obtained. For the platinum target, we identified the production of {sup 188–189–191–195}Pt, {sup 191–192–193–194–195–196}Au and {sup 186–188–189–190–192–194–189–190–192–194}Ir. For example, at the lower energies (53 and 65MeV), we measured {sup 191}Pt production cross-sections of 144mb and 157mb. Considerable care was needed in following the process of dissolving and diluting the samples to get consistent results. The new LARA array will help us better ascertain the absolute efficiency of the counting

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

High-accuracy mass measurements of neutron-rich Kr isotopes

CERN Document Server

Delahaye, P; Blaum, K; Carrel, F; George, S; Herfurth, F; Herlert, A; Kellerbauer, A G; Kluge, H J; Lunney, D; Schweikhard, L; Yazidjian, C

2006-01-01

The atomic masses of the neutron-rich krypton isotopes 84,86-95Kr have been determined with the tandem Penning trap mass spectrometer ISOLTRAP with uncertainties ranging from 20 to 220 ppb. The masses of the short-lived isotopes 94Kr and 95Kr were measured for the first time. The masses of the radioactive nuclides 89Kr and 91Kr disagree by 4 and 6 standard deviations, respectively, from the present Atomic-Mass Evaluation database. The resulting modification of the mass surface with respect to the two-neutron separation energies as well as implications for mass models and stellar nucleosynthesis are discussed.

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.

Calculated intensity of high-energy neutron beams

International Nuclear Information System (INIS)

Mustapha, B.; Nolen, J.A.; Back, B.B.

2004-01-01

The flux, energy and angular distributions of high-energy neutrons produced by in-flight spallation and fission of a 400 MeV/A 238 U beam and by the break-up of a 400 MeV/A deuteron beam are calculated. In both cases very intense secondary neutron beams are produced, peaking at zero degrees, with a relatively narrow energy spread. Such secondary neutron beams can be produced with the primary beams from the proposed rare isotope accelerator driver linac. The break-up of a 400 kW deuteron beam on a liquid-lithium target can produce a neutron flux of >10 10 neutrons/cm 2 /s at a distance of 10 m from the target

Neutrino energy loss rates due to key iron isotopes for core-collapse physics

International Nuclear Information System (INIS)

Nabi, J.-U.

2008-07-01

Accurate estimates of neutrino energy loss rates are needed for the study of the late stages of the stellar evolution, in particular for the cooling of neutron stars and white dwarfs. The energy spectra of neutrinos and antineutrinos arriving at the Earth can also provide useful information on the primary neutrino fluxes as well as neutrino mixing scenario. Proton-neutron quasi-particle random phase approximation (pn-QRPA) theory has recently being used for a microscopic calculation of stellar weak interaction rates of fp-shell nuclide, particularly iron isotopes, with success. Here I present the calculation of neutrino and antineutrino energy loss rates due to key iron isotopes in stellar matter using the pn-QRPA theory. The rates are calculated on a fine grid of temperature-density scale suitable for core-collapse simulators. The calculated rates are compared against earlier calculations. The neutrino cooling rates due to even-even isotopes of iron, 54,56 Fe, are in good agreement with the rates calculated using the large-scale shell model. The pn-QRPA calculated neutrino energy loss rates due to 55 Fe are enhanced roughly around an order of magnitude compared to the large-scale shell model calculation during the oxygen and silicon shell burning stages of massive stars and favor a lower entropy for the cores of massive stars. (author)

Advanced Multiphysics Thermal-Hydraulics Models for the High Flux Isotope Reactor

Energy Technology Data Exchange (ETDEWEB)

Jain, Prashant K [ORNL; Freels, James D [ORNL

2015-01-01

Engineering design studies to determine the feasibility of converting the High Flux Isotope Reactor (HFIR) from using highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL). This work is part of an effort sponsored by the US Department of Energy (DOE) Reactor Conversion Program. HFIR is a very high flux pressurized light-water-cooled and moderated flux-trap type research reactor. HFIR s current missions are to support neutron scattering experiments, isotope production, and materials irradiation, including neutron activation analysis. Advanced three-dimensional multiphysics models of HFIR fuel were developed in COMSOL software for safety basis (worst case) operating conditions. Several types of physics including multilayer heat conduction, conjugate heat transfer, turbulent flows (RANS model) and structural mechanics were combined and solved for HFIR s inner and outer fuel elements. Alternate design features of the new LEU fuel were evaluated using these multiphysics models. This work led to a new, preliminary reference LEU design that combines a permanent absorber in the lower unfueled region of all of the fuel plates, a burnable absorber in the inner element side plates, and a relocated and reshaped (but still radially contoured) fuel zone. Preliminary results of estimated thermal safety margins are presented. Fuel design studies and model enhancement continue.

Dynamic isotope effect on the product energy partitioning in CH2OH+→CHO++H2

Science.gov (United States)

Rhee, Young Min; Kim, Myung Soo

1998-10-01

The deuterium isotope effect on the product energy partitioning in the title reaction was investigated both experimentally and theoretically. The measured kinetic energy release (KER) showed a significant dependence on the position of deuteration. A reliable potential energy surface of the reaction was constructed from ab initio results using the recently developed interpolation algorithm. The classical trajectory calculation on this surface well reproduced the experimental finding. Close inspection of the potential energy surface revealed that the isotope effect on KER and the product rotations arose from the alteration of the symmetry of the reaction path near the transition state induced by the mass change upon isotopic substitution. The product vibrations were found to be affected by the change in the coupling constants which also arose from the mass-dependent change in the reaction path. Possibility of the quantum mechanical tunneling was also considered. Tunneling-corrected classical trajectory results were in excellent agreement with the experimental ones, indicating that the reaction proceeds via barrier penetration below the threshold.

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)

High-energy neutron yields in interactions of carbon ions with 114Sn and 124Sn nuclei

International Nuclear Information System (INIS)

Blinov, M.B.; Gavrilov, B.P.; Kovalenko, S.S.; Kozulin, Eh.M.; Mozhaev, A.N.; Oganesyan, Yu.Ts.; Penionzhkevich, Yu.Eh.

1984-01-01

The measurements of the yields of neutrons (energy more than 5 MeV) emitted in the interactions of carbon-12 ions (9 MeV/nucl.) with nuclei of two tin isotopes are conducted. The results obtained prove the effect of nucleon composition of a nucleus on the process of formation of high-energy neutrons. To clarify the concrete interaction mechanism it is necessary to perform systematic research for a number of isotopes differing in the relation of the number of neutrons and protons and binding energies of the last neutron

Thulium heat source for high-endurance and high-energy density power systems

International Nuclear Information System (INIS)

Walter, C.E.; Kammeraad, J.E.; Van Konynenburg, R.; VanSant, J.H.

1991-05-01

We are studying the performance characteristics of radioisotope heat source designs for high-endurance and high-energy-density power systems that use thulium-170. Heat sources in the power range of 5--50 kW th coupled with a power conversion efficiency of ∼30%, can easily satisfy current missions for autonomous underwater vehicles. New naval missions will be possible because thulium isotope power systems have a factor of one-to-two hundred higher endurance and energy density than chemical and electrochemical systems. Thulium-170 also has several other attractive features, including the fact that it decays to stable ytterbium-170 with a half-life of four months. For terrestrial applications, refueling on that time scale should be acceptable in view of the advantage of its benign decay. The heat source designs we are studying account for the requirements of isotope production, shielding, and integration with power conversion components. These requirements are driven by environmental and safety considerations. Thulium is present in the form of thin refractory thulia disks that allow power conversion at high peak temperature. We give estimates of power system state points, performance, mass, and volume characteristics. Monte Carlo radiation analysis provides a detailed assessment of shield requirements and heat transfer under normal and distressed conditions is also considered. 11 refs., 7 figs., 4 tabs

Design and Performance of Energy Conversion Units of Betavoltaic Isotopic Batteries

International Nuclear Information System (INIS)

Wang Guanquan; Yang Yuqing; Zhang Huaming; Hu Rui; Wei Hongyuan; Xiong Xiaoling; Luo Shunzhong

2010-01-01

Based on the single crystal silicon semiconductor junction devices, the relationships between their configurable parameters and the electrical properties were discussed for the purpose of design of energy conversion units of betavoltaic isotopic batteries. Two kinds of silicon semiconductor junction devices as energy conversion units of betavoltaic batteries were designed and customized. The electrical output properties of the devices irradiated by 63 Ni source were measured. The results show that the new designed devices perform better than the existing commercial one in open-circuit voltage, output power and energy conversion efficiency. (authors)

Energy-switching potential energy surface for the water molecule revisited: A highly accurate singled-sheeted form.

Science.gov (United States)

Galvão, B R L; Rodrigues, S P J; Varandas, A J C

2008-07-28

A global ab initio potential energy surface is proposed for the water molecule by energy-switching/merging a highly accurate isotope-dependent local potential function reported by Polyansky et al. [Science 299, 539 (2003)] with a global form of the many-body expansion type suitably adapted to account explicitly for the dynamical correlation and parametrized from extensive accurate multireference configuration interaction energies extrapolated to the complete basis set limit. The new function mimics also the complicated Sigma/Pi crossing that arises at linear geometries of the water molecule.

Laser isotope separation studies in JAERI

International Nuclear Information System (INIS)

Arisawa, Takashi; Shiba, Koreyuki

1986-01-01

For uranium enrichment, Japan Atomic Energy Research Institute (JAERI) has been studying atomic vapor laser isotope separation since 1976, in addition to such separation methods as gas diffusion, chemical exchange and gas-dynamic techniques. Studies carried out to date in JAERI is briefly summarized in the first part of the report. Then, some major separation techniques which have been studied in JAERI are outlined, and typical results obtained are presented. A large part is devoted to the multiple-photon photoionization technique, which is commonly known as the atomic laser isotope separation method for uranium enrichment. It has such advantages as 1) very high spectral selectivity for the relevant isotope and 2) highly improved photoionizing effect by means of two- and three-step resonance photoionization processes. Here, the atomic laser isotope separation method is discussed in detail with respect to the evaporation process, energy levels, photoionization, selectivity, photoionization schemes, ion recovery, separation in macroscopic amounts, and separation of trace amounts of isotopes. Typical observed and claculated results related to these subjects are shown. In addition, the report briefly describes some other separation processes including laser induced chemical reaction, multiple photo-dissociation, multiple-photo excitation and UV dissociation, laser induced thermal diffusion, and laser centrifugation. (Nogami, K.)

High-frequency field-deployable isotope analyzer for hydrological applications

Science.gov (United States)

Elena S.F. Berman; Manish Gupta; Chris Gabrielli; Tina Garland; Jeffrey J. McDonnell

2009-01-01

A high-frequency, field-deployable liquid water isotope analyzer was developed. The instrument was deployed for 4 contiguous weeks in the H. J. Andrews Experimental Forest Long-term Ecological Research site in western Oregon, where it was used for real-time measurement of the isotope ratios of precipitation and stream water during three large storm events. We were able...

High energy nuclear data evaluations for neutron-, proton-, and photon-induced reactions at KAERI

International Nuclear Information System (INIS)

Lee, Young Ouk; Chang, Jong Hwa; Kim, Doo Hwan; Lee, Jeong Yeon; Han, Yinlu; Sukhovitski, Efrem Sh.

2001-01-01

The Korea Atomic Energy Research Institute (KAERI) is building high energy neutron-, proton-, and photon-induced nuclear data libraries for energies up to hundreds MeV in response to nuclear data needs from various R and Ds and applications. The librares provide nuclear data needed for the accelerator-driven transmutation of nuclear waste and radiation transport simulations of cancer radiotherapy. The neutron library currently has 10 isotopes such as C-12, N-14, O-16, Al-27, Si-28, Ca-40, Fe-56, Ni-58, Zr-90, Sn-120, and Pb-208 for energies from 20 up to 400 MeV. The proton nuclear data were evaluated in a consistent manner with the neutron case, using the same nuclear model parameters. In addition to the same isotopes included in the neutron library, the proton library has 70 extra isotopes of 24 elements ranging from nitrogen to lead up to 150 MeV for which the evaluations are focused on the medical and activation analyses applications. The photonuclear data library has been built along with international collaboration by participating in the IAEA's Coordinated Research Project (CRP) which ended last year. Currently the KAERI photonuclear library includes 143 isotopes of 39 elements

EBIS/T charge breeding for intense rare isotope beams at MSU

CERN Document Server

Schwarz, S; Marrs, R E; Kittimanapun, K; Lapierre, A; Mendez, A J; Ames, F; Beene, J R; Lindroos, M; Ahle, L E; Stracener, D W; Kester, O; Wenander, F; Lopez-Urrutia, J R Crespo; Dilling, J; Bollen, G

2010-01-01

Experiments with reaccelerated beams are an essential component of the science program of existing and future rare isotope beam facilities. NSCL is currently constructing ReA3, a reaccelerator for rare isotopes that have been produced by projectile fragmentation and in-flight fission and that have been thermalized in a gas stopper. The resulting low-energy beam will be brought to an Electron Beam Ion Source/Trap (EBIS/T) in order to obtain highly charged ions at an energy of 12 keV/u. This charge breeder is followed by a compact linear accelerator with a maximum beam energy of 3MeV/u for U-238 and higher energies for lighter isotopes. Next-generation rare isotope beam facilities like the Facility for Rare Isotope Beams FRIB, but also existing Isotope Separator On-line (ISOL) facilities are expected to provide rare-isotope beam rates in the order of 10(11) particles per second for reacceleration. At present the most promising scheme to efficiently start the reacceleration of these intense beams is the use of a...

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)

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

Isotopic effects on phonon anharmonicity in layered van der Waals crystals: Isotopically pure hexagonal boron nitride

Science.gov (United States)

Cuscó, Ramon; Artús, Luis; Edgar, James H.; Liu, Song; Cassabois, Guillaume; Gil, Bernard

2018-04-01

Hexagonal boron nitride (h -BN) is a layered crystal that is attracting a great deal of attention as a promising material for nanophotonic applications. The strong optical anisotropy of this crystal is key to exploit polaritonic modes for manipulating light-matter interactions in 2D materials. h -BN has also great potential for solid-state neutron detection and neutron imaging devices, given the exceptionally high thermal neutron capture cross section of the boron-10 isotope. A good knowledge of phonons in layered crystals is essential for harnessing long-lived phonon-polariton modes for nanophotonic applications and may prove valuable for developing solid-state 10BN neutron detectors with improved device architectures and higher detection efficiencies. Although phonons in graphene and isoelectronic materials with a similar hexagonal layer structure have been studied, the effect of isotopic substitution on the phonons of such lamellar compounds has not been addressed yet. Here we present a Raman scattering study of the in-plane high-energy Raman active mode on isotopically enriched single-crystal h -BN. Phonon frequency and lifetime are measured in the 80-600-K temperature range for 10B-enriched, 11B-enriched, and natural composition high quality crystals. Their temperature dependence is explained in the light of perturbation theory calculations of the phonon self-energy. The effects of crystal anisotropy, isotopic disorder, and anharmonic phonon-decay channels are investigated in detail. The isotopic-induced changes in the phonon density of states are shown to enhance three-phonon anharmonic decay channels in 10B-enriched crystals, opening the possibility of isotope tuning of the anharmonic phonon decay processes.

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

The effect of zero-point energy differences on the isotope dependence of the formation of ozone: a classical trajectory study.

Science.gov (United States)

Schinke, Reinhard; Fleurat-Lessard, Paul

2005-03-01

The effect of zero-point energy differences (DeltaZPE) between the possible fragmentation channels of highly excited O(3) complexes on the isotope dependence of the formation of ozone is investigated by means of classical trajectory calculations and a strong-collision model. DeltaZPE is incorporated in the calculations in a phenomenological way by adjusting the potential energy surface in the product channels so that the correct exothermicities and endothermicities are matched. The model contains two parameters, the frequency of stabilizing collisions omega and an energy dependent parameter Delta(damp), which favors the lower energies in the Maxwell-Boltzmann distribution. The stabilization frequency is used to adjust the pressure dependence of the absolute formation rate while Delta(damp) is utilized to control its isotope dependence. The calculations for several isotope combinations of oxygen atoms show a clear dependence of relative formation rates on DeltaZPE. The results are similar to those of Gao and Marcus [J. Chem. Phys. 116, 137 (2002)] obtained within a statistical model. In particular, like in the statistical approach an ad hoc parameter eta approximately 1.14, which effectively reduces the formation rates of the symmetric ABA ozone molecules, has to be introduced in order to obtain good agreement with the measured relative rates of Janssen et al. [Phys. Chem. Chem. Phys. 3, 4718 (2001)]. The temperature dependence of the recombination rate is also addressed.

Investigating Pathways of Nutrient and Energy Flows Through Aquatic Food Webs Using Stable Isotopes of Carbon and Nitrogen

Energy Technology Data Exchange (ETDEWEB)

Hadwen, W. L.; Bunn, S. E. [Australian Rivers Institute, Griffith School of Environment, Griffith University, Nathan Campus, Brisbane, Queensland (Australia)

2013-05-15

Carbon and nitrogen stable isotopes can provide valuable insights into pathways of nutrient and energy flows in aquatic ecosystems. Carbon stable isotopes are principally used to trace pathways of organic matter transfer through aquatic food webs, particularly with regard to identifying the dominant sources of nutrition for aquatic biota. Stable isotopes of carbon have been widely used to answer one of the most pressing questions in aquatic food web ecology - to what degree do in-stream (autochthonous) and riparian (allochthonous) sources of energy fuel riverine food webs? In conjunction with carbon stable isotopes, nitrogen stable isotopes have been used to determine the trophic position of consumers and to identify the number of trophic levels in aquatic food webs. More recently, stable nitrogen isotopes have been recommended as indicators of anthropogenic disturbances. Specifically, agricultural land uses and/or sewage effluent discharge have been shown to significantly increase {delta}{sup 15}N signatures in primary producers and higher order consumers in freshwater, estuarine and marine environments. Together, carbon and nitrogen stable isotopes can be used to examine natural food web functions as well as the degree to which human modifications to catchments and aquatic environments can influence aquatic ecosystem function. (author)

Cooperation on Improved Isotopic Identification and Analysis Software for Portable, Electrically Cooled High-Resolution Gamma Spectrometry Systems Final Report

Energy Technology Data Exchange (ETDEWEB)

Dreyer, Jonathan G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wang, Tzu-Fang [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vo, Duc T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Funk, Pierre F. [Inst. for Radiological Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses (France); Weber, Anne-Laure [Inst. for Radiological Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses (France)

2017-07-20

Under a 2006 agreement between the Department of Energy (DOE) of the United States of America and the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) of France, the National Nuclear Security Administration (NNSA) within DOE and IRSN initiated a collaboration to improve isotopic identification and analysis of nuclear material [i.e., plutonium (Pu) and uranium (U)]. The specific aim of the collaborative project was to develop new versions of two types of isotopic identification and analysis software: (1) the fixed-energy response-function analysis for multiple energies (FRAM) codes and (2) multi-group analysis (MGA) codes. The project is entitled Action Sheet 4 – Cooperation on Improved Isotopic Identification and Analysis Software for Portable, Electrically Cooled, High-Resolution Gamma Spectrometry Systems (Action Sheet 4). FRAM and MGA/U235HI are software codes used to analyze isotopic ratios of U and Pu. FRAM is an application that uses parameter sets for the analysis of U or Pu. MGA and U235HI are two separate applications that analyze Pu or U, respectively. They have traditionally been used by safeguards practitioners to analyze gamma spectra acquired with high-resolution gamma spectrometry (HRGS) systems that are cooled by liquid nitrogen. However, it was discovered that these analysis programs were not as accurate when used on spectra acquired with a newer generation of more portable, electrically cooled HRGS (ECHRGS) systems. In response to this need, DOE/NNSA and IRSN collaborated to update the FRAM and U235HI codes to improve their performance with newer ECHRGS systems. Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL) performed this work for DOE/NNSA.

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

Double and triple isotope gamma camera studies with energy selection after data collection

International Nuclear Information System (INIS)

Soussaline, F.; Raynaud, C.; Kacperek, A.; Kellershohn, C.; Sauce, M.; Zadje, C.

1974-01-01

A system comprising a Toshiba camera and a Informatek data processing system has been used to perform multiple isotope studies. A large window (30-550KeV) is used and the data can be manipulated after data collection, to form sets of dynamic frames for various energies. Linear combinations of matrices have been used to correct for scattering. Double isotope studies using 197Hg/198Au have been used to determine Hg renal uptake in man, and are compared to a previous technique requiring two separate data acquisitions. Animal (pig) renal experiments have been performed using 169 Yb/sup(99m)Tc/ 197 Hg. This pilot study gave good results and indicates the utility of the system for multiple isotope function studies in man [fr

High precision isotopic ratio analysis of volatile metal chelates

International Nuclear Information System (INIS)

Hachey, D.L.; Blais, J.C.; Klein, P.D.

1980-01-01

High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50 Cr, 60 Ni, and 65 Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60 Ni (0.02-2.15 at. % excess) and 62 Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26 Mg and 44 Ca, was analyzed by EI/MS. 1 figure, 5 tables

High-Resolution Energy and Intensity Measurements with CVD Diamond at REX-ISOLDE

CERN Document Server

Griesmayer, E; Dobos, D; Wenander, F; Bergoz, J; Bayle, H; Frais-Kölbl, H; Leinweber, J; Aumeyr, T; CERN. Geneva. BE Department

2009-01-01

A novel beam instrumentation device for the HIE-REX (High In-tensity and Energy REX) upgrade has been developed and tested at the On-Line Isotope Mass Separator ISOLDE, located at the European Laboratory for Particle Physics (CERN). This device is based on CVD diamond detector technology and is used for measuring the beam intensity, particle counting and measuring the energy spectrum of the beam. An energy resolution of 0.6% was measured at a carbon ion energy of 22.8 MeV. This corresponds to an energy spread of ± 140 keV.

High energy x-radiographic assessment of conditioned intermediate level waste blocks

International Nuclear Information System (INIS)

Lewcock, A.I.; Burch, S.F.; Reynolds, W.N.; Pullen, D.A.W.; Smith, D.

1985-07-01

This report describes an effective technique for examining the quality of the solidification matrix material in a 500 litre waste drum, testing for homogeneity and major cracks and the confirmation of set. A high energy x-ray source, (an 8 MeV Linac) and a special x-ray TV system, were used to examine several different types of solidified waste form, with and without background radiation, simulated by the use of an uncollimated radiographic isotope. The system as tested showed no discernable image degradation when the isotope was positioned to give a representative background dose as experienced with active ILW monoliths. (author)

Energy dependence of isotopic spectra from spallation residues; Dependance en energie des spectres isotopiques de residus de spallation

Energy Technology Data Exchange (ETDEWEB)

Audouin, L

2003-09-01

Spallation reactions are collisions between heavy nuclei and light particle with an energy of a few hundreds MeV. The y are considered as a suitable way to create high- flux neutrons sources, which may used for example for the transmutation of nuclear wastes (hybrid reactors). The study of the residues from such reactions is both a way to understand the physics of the spallation and to provide information required for the design of industrial targets. The residues from the spallation of lead by proton at 500 MeV have been measured using the inverse kinematics technique in the FRS (fragments recoil separator). spectrometer from GSI (Barmstadt). This low energy required the use of new technique, for the experimental setup as well as during the analysis. The fragments were identified in-flight, prior to {beta} decay. Complete isotopic distributions are obtained with an accuracy ranging between 10 and 30%. Detailed information on the reaction kinematics are also obtained. Data are in excellent agreement with radio-chemical measurements, and bring new insights about the spallation process. The comparison with data measured on the same system with an incident energy of 1 GeV allows to discuss the influence of the projectile energy on the residues formation. It is concluded that the independence of the shape of the isobaric production cross sections regarding mass and energy of the projectile is preserved at low incident energies. The behaviour of Monte-Carlo codes is discussed with respect to those sets of data. The calculations show an improving agreement with decreasing energy, indicating that high-energy phenomena, for which some common assumptions become questionable, are the main reason for the observed discrepancies. (author)

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.

High Sensitivity Detection of Xe Isotopes Via Beta-Gamma Coincidence Counting

International Nuclear Information System (INIS)

Bowyer, Ted W.; McIntyre, Justin I.; Reeder, Paul L.

1999-01-01

Measurement of xenon fission product isotopes is a key element in the global network being established to monitor the Comprehensive Nuclear-Test-Ban Treaty. Pacific Northwest National Laboratory has developed an automated system for separating Xe from air which includes a beta-gamma counting system for 131mXe, 133mXe, 133Xe, and 135Xe. Betas and conversion electrons are detected in a plastic scintillation cell containing the Xe sample. The counting geometry is nearly 100% for beta and conversion electrons. The resolution in the pulse height spectrum from the plastic scintillator is sufficient to observe distinct peaks for specific conversion electrons. Gamma and X-rays are detected in a NaI(Tl) scintillation detector which surrounds the plastic scintillator sample cell. Two-dimensional pulse height spectra of gamma energy versus beta energy are obtained. Each of the four xenon isotopes has a distinctive signature in the two-dimensional energy array. The details of the counting system, examples of two-dimensional beta-gamma data, and operational experience with this counting system will be described

Isospin splitting of nucleon effective mass and symmetry energy in isotopic nuclear reactions

Science.gov (United States)

Guo, Ya-Fei; Chen, Peng-Hui; Niu, Fei; Zhang, Hong-Fei; Jin, Gen-Ming; Feng, Zhao-Qing

2017-10-01

Within an isospin and momentum dependent transport model, the dynamics of isospin particles (nucleons and light clusters) in Fermi-energy heavy-ion collisions are investigated for constraining the isospin splitting of nucleon effective mass and the symmetry energy at subsaturation densities. The impacts of the isoscalar and isovector parts of the momentum dependent interaction on the emissions of isospin particles are explored, i.e., the mass splittings of and (). The single and double neutron to proton ratios of free nucleons and light particles are thoroughly investigated in the isotopic nuclear reactions of 112Sn+112Sn and 124Sn+124Sn at incident energies of 50 and 120 MeV/nucleon, respectively. It is found that both the effective mass splitting and symmetry energy impact the kinetic energy spectra of the single ratios, in particular at the high energy tail (larger than 20 MeV). The isospin splitting of nucleon effective mass slightly impacts the double ratio spectra at the energy of 50 MeV/nucleon. A soft symmetry energy with stiffness coefficient of γ s=0.5 is constrained from the experimental data with the Fermi-energy heavy-ion collisions. Supported by Major State Basic Research Development Program in China (2014CB845405, 2015CB856903), National Natural Science Foundation of China (11722546, 11675226, 11675066, U1332207) and Youth Innovation Promotion Association of Chinese Academy of Sciences

Very low-energy conversion electron detection (VLECED) system at the isocele on-line isotope separator, Orsay

International Nuclear Information System (INIS)

Kilcher, P.; Sauvage, J.; Munsch, J.; Obert, J.; Caruette, A.; Ferro, A.; Boissier, G.; Fournet-Fayas, J.; Ducourtieux, M.; Landois, G.

1988-01-01

A system designed and installed at the on-line isotope separator ISOCELE II allows the high resolution detection of low-energy conversion electrons (down to 1 keV) emitted by mass separated radioactive sources: the use of a special tape transport permits both the slowing down of the incoming beam of radioactive ions up to a collection point and the acceleration of the electrons emitted by the collected sources brought to a flat magnetic spectrograph. Typical spectra so obtained are presented

Further development of IDGS: Isotope dilution gamma-ray spectrometry

International Nuclear Information System (INIS)

Li, T.K.; Parker, J.L.; Kuno, Y.; Sato, S.; Kamata, M.; Akiyama, T.

1991-01-01

The isotope dilution gamma-ray spectrometry (IDGS) technique for determining the plutonium concentration and isotopic composition of highly radioactive spent-fuel dissolver solutions has been further developed. Both the sample preparation and the analysis have been improved. The plutonium isotopic analysis is based on high-resolution, low-energy gamma-ray spectrometry. The plutonium concentration in the dissolver solutions then is calculated from the measured isotopic differences among the spike, the dissolver solution, and the spiked dissolver solution. Plutonium concentrations and isotopic compositions of dissolver solutions analyzed from this study agree well with those obtained by traditional isotope dilution mass spectrometry (IDMS) and are consistent with the first IDGS experimental result. With the current detector efficiency, sample size, and a 100-min count time, the estimated precision is ∼0.5% for 239 Pu and 240 Pu isotopic analyses and ∼1% for the plutonium concentration analysis. 5 refs., 2 figs., 7 tabs

Isotope Production and Distribution Program`s Fiscal Year 1997 financial statement audit

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-27

The Department of Energy Isotope Production and Distribution Program mission is to serve the national need for a reliable supply of isotope products and services for medicine, industry and research. The program produces and sells hundreds of stable and radioactive isotopes that are widely utilized by domestic and international customers. Isotopes are produced only where there is no U.S. private sector capability or other production capacity is insufficient to meet U.S. needs. The Department encourages private sector investment in new isotope production ventures and will sell or lease its existing facilities and inventories for commercial purposes. The Isotope Program reports to the Director of the Office of Nuclear Energy, Science and Technology. The Isotope Program operates under a revolving fund established by the Fiscal Year (FY) 1990 Energy and Water Appropriations Act and maintains financial viability by earning revenues from the sale of isotopes and services and through annual appropriations. The FY 1995 Energy and Water Appropriations Act modified predecessor acts to allow prices charged for Isotope Program products and services to be based on production costs, market value, the needs of the research community, and other factors. Although the Isotope Program functions as a business, prices set for small-volume, high-cost isotopes that are needed for research purposes may not achieve full-cost recovery. As a result, isotopes produced by the Isotope Program for research and development are priced to provide a reasonable return to the U.S. Government without discouraging their use. Commercial isotopes are sold on a cost-recovery basis. Because of its pricing structure, when selecting isotopes for production, the Isotope Program must constantly balance current isotope demand, market conditions, and societal benefits with its determination to operate at the lowest possible cost to U.S. taxpayers. Thus, this report provides a financial analysis of this situation.

Plutonium characterisation with prompt high energy gamma-rays from (n,gamma) reactions for nuclear warhead dismantlement verification

Energy Technology Data Exchange (ETDEWEB)

Postelt, Frederik; Gerald, Kirchner [Carl Friedrich von Weizsaecker-Centre for Science and Peace Research, Hamburg (Germany)

2015-07-01

Measurements of neutron induced gammas allow the characterisation of fissile material (i.e. plutonium and uranium), despite self- and additional shielding. Most prompt gamma-rays from radiative neutron capture reactions in fissile material have energies between 3 and 6.5 MeV. Such high energy photons have a high penetrability and therefore minimise shielding and self-absorption effects. They are also isotope specific and therefore well suited to determine the isotopic composition of fissile material. As they are non-destructive, their application in dismantlement verification is desirable. Disadvantages are low detector efficiencies at high gamma energies, as well as a high background of gammas which result from induced fission reactions in the fissile material, as well as delayed gammas from both, (n,f) and(n,gamma) reactions. In this talk, simulations of (n,gamma) measurements and their implications are presented. Their potential for characterising fissile material is assessed and open questions are addressed.

Inter-comparison of High Energy Files (neutron-induced, from 20 to 150 MeV)

Energy Technology Data Exchange (ETDEWEB)

Lee, Young-Ouk; Fukahori, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-11-01

Recent new applications using accelerator-driven system require well-tested nuclear data when modeling the interaction of neutrons above 20 MeV. This work is aimed to review evaluation methods applied in currently available neutron high energy files above 20 to 150 MeV, to inter-compare their evaluated cross sections on some important isotopes, and to analyze resulting discrepancies. Through out these, integrities and consistencies of the high energy files are checked, applicability of physics models and evaluation methodologies are assessed, and some directions are derived to improve and expand current JENDL High Energy File. (author)

Job/task analysis for I ampersand C [Instrumentation and Controls] instrument technicians at the High Flux Isotope Reactor

International Nuclear Information System (INIS)

Duke, L.L.

1989-09-01

To comply with Department of Energy Order 5480.XX (Draft), a job/task analysis was initiated by the Maintenance Management Department at Oak Ridge National Laboratory (ORNL). The analysis was applicable to instrument technicians working at the ORNL High Flux Isotope Reactor (HFIR). This document presents the procedures and results of that analysis. 2 refs., 2 figs

Production of high-purity isotopes by electromagnetic separation; Production electromagnetique d'isotope tres purs

Energy Technology Data Exchange (ETDEWEB)

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

1958-07-01

Improvement in isotopic purity of nuclides prepared by electromagnetic separation is searched into the principle of cascades of monochromators. The principal drawback of which is to allow the separation of only one isotope at a time. The electromagnetic separator of Saclay is equipped with an electrostatic post-analyzer, which is described. Significant results are obtained, concerning isotopic enhancements of uranium-235 and mercury-204. A schema of isotopic contagion is then proposed, the basis of it is the scattering of the primary ions in the residual atmosphere of the separator chamber. The most frequent type of collisions being accompanied by neutralisation of the ions, the schema explains the efficiency of the second stage. As a matter of conclusion, some particularities concerning the routine work at a high enhancement, small output machine, are given. (author) [French] L'accroissement de la purete isotopique des especes nucleaires preparees par separation electromagnetique est recherche dans l'emploi du principe des cascades de monochromateurs, moyennant la servitude de ne collecter qu'un isotope a la fois. Le separateur electromagnetique de Saclay est equipe dans ce but d'un post-analyseur electrostatique, qui est decrit. Des resultats significatifs sont donnes, portant sur les enrichissements obtenus dans les separations d'uranium-235 et de mercure-204. Un schema de contagion isotopique est propose. Il est fonde sur la diffusion a petit angle accompagnant la neutralisation des faisceaux primaires par collision avec le gaz residuel. Ce schema permet d'expliquer l'efficacite de l'etage electrostatique. En matiere de conclusion, la methode d'exploitation d'une machine a faible debit et a haut enrichissement est donnee. (auteur)

Preparation of inorganic ion exchangers with high selectivity for lithium isotopes

International Nuclear Information System (INIS)

Oi, Takao

2004-01-01

Development of ion exchangers that show large lithium isotope effects is hoped for to establish highly efficient chromatographic processes of lithium isotope separation. In this paper, preparation, characterization, ion exchange properties, and lithium isotope selectivity of inorganic materials that have been and still are being studied by my research group at Sophia University are reviewed. They include manganese oxides-based ion exchangers, antimonic acids and titanium/zirconium phosphates-based ion exchangers. As a result, the lithium isotope separation effects that were one order of magnitude larger than those of organic ion exchangers were obtained. Some inorganic ion exchangers were found to show ion exchange rates more than comparable to those of organic ones. (author)

Isotope shift studies in the spectra of gadolinium in UV region and term shifts of high even levels of Gd I

International Nuclear Information System (INIS)

Afzal, S.M.; Venugopalan, A.; Ahmad, S.A.

1997-01-01

Isotope shift Δσ( 156 Gd- 160 Gd) is reported in 70 spectral lines of neutral gadolinium atom (Gd I) in the 3290-3920 A region providing isotope shift data in UV lines of Gd I spectrum for the first time. The measurements were carried out on a photoelectric recording Fabry-Perot Spectrometer using highly enriched isotopic samples of gadolinium. Term isotope shifts ΔT( 156 Gd- 160 Gd) have been evaluated for 48 high lying even parity energy levels of Gd I using this data; new ΔT values have been obtained for 24 levels. Electronic configurations 4f 7 5d6s6p, 4f 7 5d 2 6p and 4f 8 5d6s assigned earlier to these even levels have been either confirmed or configuration mixing pointed out in some of these levels. Probable assignment of 4f 8 5d6s configuration to 8 even levels between 32930 and 35500 cm -1 have been confirmed. (orig.)

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

Advances in the production of isotopes and radiopharmaceuticals at the Atomic Energy Corporation of South Africa

International Nuclear Information System (INIS)

Louw, P.A.; De Villiers, W.Y.Z.; Jarvis, N.V.

1997-01-01

The Atomic Energy Corporation of South Africa Ltd (AEC) owns and operates the 20 MW research reactor, SAFARI-1. Utilisation of the reactor has in recent years changed from research and materials testing to the production of isotopes. The most important breakthrough achieved in recent years is the production of high quality fission 99Mo. This has been produced routinely since April 1993 and supplied to clients across the world. A capability for the reliable production of 1000 Ci of 99Mo per week (calibrated for six days after production) has been proven. The AEC has also established facilities to produce its own 99mTc generators together with a most of radiopharmaceutical kits for diagnostic nuclear medicine purposes. The production of 153 Sm and 131 I (tellurium oxide route) has been operational for many years. Applications include therapeutic radiopharmaceuticals such as 153 Sm-EDTMP for bone cancer pain palliation, 13' I-Lipiodol for liver cancer and 131 I capsules for thyroid treatment. Facilities for the production of other isotopes such as 131 I (from fission), 32 P and 35 S are in various stages of completion. Extensive analytical methods and equipment have been developed and are routinely used to certify the quality of exported isotopes. Irradiation and encapsulation of 192 Ir is also performed routinely at the AEC. Modern facilities allow for the production of isotopes such as 131 Ba and 140 La on an ad hoc basis. Quality assurance procedures based on ISO9000 were developed for all aspects of the production of the various isotopes. Documentation, such as Drug Master Files, required by authorities in various countries has also been submitted and accepted

Total β-decay energies and masses of tin, antimony and tellurium isotopes in the vicinity of 50132Sn82

International Nuclear Information System (INIS)

Lund, E.; Aleklett, K.; Rudstam, G.

1977-01-01

Experimental β-decay energies for short-lived isotopes of tin, antimony and tellurium are presented. Mass-separated sources were produced at the on-line isotope separator OSIRIS. By applying β-γ coincidence methods, total β-decay energies have been determined for the following nuclides: 127-131 Sn, 128 130 131 134 Sb and 134 135 Te. The atomic mass excess has been derived for these nuclei, and comparisons are made with mass formula predictions. (Auth.)

Research and development studies into isotope production using the Harwell Variable Energy Cyclotron

International Nuclear Information System (INIS)

Nichols, A.L.; Bett, R.; Cuninghame, J.G.; Goodall, J.A.B.; Hill, J.I.S.; Sims, H.E.; Willis, H.H.

1979-11-01

Many useful radioisotopes can be produced by means of the Harwell Chemistry Division's Variable Energy Cyclotron. This report describes the preliminary preparation of a number of these neutron deficient isotopes (i.e. F18, S38, Fe52, Sr82-Rb82, Nb92m, Rh99, I123, Xe125, Tl201, Pu236, Pu237). Recently a targetry development programme has been initiated to optimise isotope yields. Gas, liquid and solid targets have been designed that can be quickly and safely removed from the cyclotron beam-line so that the target activity can be rapidly processed after the irradiation, if necessary. (author)

Isotopic composition of neon in the galactic cosmic rays: a high resolution measurement

International Nuclear Information System (INIS)

Greiner, D.E.; Wiedenbeck, M.E.; Bieser, F.S.; Crawford, H.J.; Heckman, H.H.; Lindstrom, P.J.

1979-06-01

A measurement of the isotopic composition of galactic cosmic ray neon in the energy range 70 to 260 MeV/amu has been made using the U.C. Berkeley HKH instrument aboard ISEE-3. A combination of high resolution and good statistical accuracy makes possible a precise determination of the local interplanetary neon composition. We find 22 Ne/ 20 Ne = 0.64 +- 0.07 and 21 Ne/ 20 Ne < 0.30 in local interplanetary space. These ratios, when interpreted in using standard galactic propagation and solar modulation models, yield cosmic ray source abundances which are inconsistent with a solar-like source composition

Empirical High-Temperature Calibration for the Carbonate Clumped Isotopes Paleothermometer

Science.gov (United States)

Kluge, T.; John, C. M.; Jourdan, A.; Davis, S.; Crawshaw, J.

2013-12-01

The clumped isotope paleothermometer is being used in a wide range of applications related to carbonate mineral formation, focusing on temperature and fluid δ18O reconstruction. Whereas the range of typical Earth surface temperatures has been the focus of several studies based on laboratory experiments and biogenic carbonates of known growth temperatures, the clumped isotope-temperature relationship above 70 °C has not been assessed by direct precipitation of carbonates. We investigated the clumped isotope-temperature relationship by precipitating carbonates between 20 and 200°C in the laboratory. The setup consists of a pressurized vessel in which carbonate minerals are precipitated from the mixture of two solutions (CaCl2, NaHCO3). Both solutions are thermally and isotopically equilibrated before injection in the pressure vessel. Minerals precipitated in this setup generally consist of calcite. Samples were reacted with 105% orthophosphoric acid for 10 min at 90°C. The evolved CO2 was continuously collected and subsequently purified with a Porapak trap held at -35°C. Measurements were performed on a MAT 253 using the protocol of Huntington et al. (2009) and Dennis et al. (2011). Clumped isotope values from 20-90°C are consistent with carbonates that were precipitated from a CaCO3 super-saturated solution using the method of McCrea (1950). This demonstrates that the experimental setup does not induce any kinetic fractionation, and can be used for high-temperature carbonate precipitation. The new clumped isotope calibration at high temperature follows the theoretical calculations of Schauble et al. (2006) adjusted for phosphoric acid digestion at 90°C. We gratefully acknowledge funding from Qatar Petroleum, Shell and the Qatar Science and Technology Park.

Chromatographic speciation of Cr(III)-species, inter-species equilibrium isotope fractionation and improved chemical purification strategies for high-precision isotope analysis.

Science.gov (United States)

Larsen, K K; Wielandt, D; Schiller, M; Bizzarro, M

2016-04-22

Chromatographic purification of chromium (Cr), which is required for high-precision isotope analysis, is complicated by the presence of multiple Cr-species with different effective charges in the acid digested sample aliquots. The differing ion exchange selectivity and sluggish reaction rates of these species can result in incomplete Cr recovery during chromatographic purification. Because of large mass-dependent inter-species isotope fractionation, incomplete recovery can affect the accuracy of high-precision Cr isotope analysis. Here, we demonstrate widely differing cation distribution coefficients of Cr(III)-species (Cr(3+), CrCl(2+) and CrCl2(+)) with equilibrium mass-dependent isotope fractionation spanning a range of ∼1‰/amu and consistent with theory. The heaviest isotopes partition into Cr(3+), intermediates in CrCl(2+) and the lightest in CrCl2(+)/CrCl3°. Thus, for a typical reported loss of ∼25% Cr (in the form of Cr(3+)) through chromatographic purification, this translates into 185 ppm/amu offset in the stable Cr isotope ratio of the residual sample. Depending on the validity of the mass-bias correction during isotope analysis, this further results in artificial mass-independent effects in the mass-bias corrected (53)Cr/(52)Cr (μ(53)Cr* of 5.2 ppm) and (54)Cr/(52)Cr (μ(54)Cr* of 13.5 ppm) components used to infer chronometric and nucleosynthetic information in meteorites. To mitigate these fractionation effects, we developed strategic chemical sample pre-treatment procedures that ensure high and reproducible Cr recovery. This is achieved either through 1) effective promotion of Cr(3+) by >5 days exposure to HNO3H2O2 solutions at room temperature, resulting in >∼98% Cr recovery for most types of sample matrices tested using a cationic chromatographic retention strategy, or 2) formation of Cr(III)-Cl complexes through exposure to concentrated HCl at high temperature (>120 °C) for several hours, resulting in >97.5% Cr recovery using a

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)

Electromagnetic moments and electric dipole transitions in carbon isotopes

International Nuclear Information System (INIS)

Suzuki, Toshio; Sagawa, Hiroyuki; Hagino, Kouichi

2003-01-01

We carry out shell model calculations to study electromagnetic moments and electric dipole transitions of C isotopes. We point out the configuration dependence of the quadrupole and magnetic moments of the odd C isotopes, which will be useful to find out the deformations and the spin parities of the ground states of these nuclei. We also study the electric dipole states of C isotopes, focusing on the interplay between low energy pigmy strength and giant dipole resonances. As far as the energies of the resonances are concerned, reasonable agreement is obtained with available experimental data for the photoreaction cross sections in 12 C, 13 C, and 14 C, both in the low energy region below (ℎ/2π)ω=14 MeV and in the high energy giant resonance region (14 MeV 15 C is found to exhaust about 12-16 % of the classical Thomas-Reiche-Kuhn sum rule value and 50-80 % of the cluster sum rule value

High-spin structure of neutron-rich Dy isotopes

Indian Academy of Sciences (India)

Neutron-rich Dy isotopes; high-spin states; g-factors; cranked HFB theory. ... for 164Dy marking a clear separation in the behaviour as a function of neutron ... cipal x-axis as the cranking axis) in this mass region we have planned to make a sys-.

High radio-isotope uptakes in patients with hypothyroidism

Energy Technology Data Exchange (ETDEWEB)

Wing, J.; Kalk, W.J.; Ganda, C. (University of the Witwatersrand, Johannesburg (South Africa). Dept. of Medicine)

1982-12-04

Hypothyroidism is usually associated with a low radio-isotope uptake by the thyriod gland. We report 8 cases of Hashimoto's thyroiditis with clinical and biochemical hypothyroidism and with borderline high or overtly increased technetium-99m pertechnetate and/or iodine-131 uptakes.

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

Level densities of iron isotopes and lower-energy enhancement of y-strength function

International Nuclear Information System (INIS)

Voinov, A V; Grimes, S M; Agvaanluvsan, U; Algin, E; Belgya, T; Brune, C R; Guttormsen, M; Hornish, M J; Massey, T N; Mitchell, G; Rekstad, J; Schiller, A; Siem, S

2005-01-01

The neutron spectrum from the 55 Mn(d,n) 56 Fe reaction has been measured at E d = 7 MeV. The level density of 56 Fe obtained from neutron evaporation spectrum has been compared to the level density from Oslo-type 57 Fe( 3 He, aγ) 56 Fe experiment [1]. The good agreement supports the recent results [1, 8] including an availability of a low-energy enhancement in the γ-strength function for iron isotopes. The new level density function allowed us to investigate an excitation energy dependence of this enhancement, which is shown to increase with increasing excitation energy

ARRONAX, a high-energy and high-intensity cyclotron for nuclear medicine

International Nuclear Information System (INIS)

Haddad, Ferid; Guertin, Arnaud; Michel, Nathalie; Ferrer, Ludovic; Carlier, Thomas; Barbet, Jacques; Chatal, Jean-Francois

2008-01-01

This study was aimed at establishing a list of radionuclides of interest for nuclear medicine that can be produced in a high-intensity and high-energy cyclotron. We have considered both therapeutic and positron emission tomography radionuclides that can be produced using a high-energy and a high-intensity cyclotron such as ARRONAX, which will be operating in Nantes (France) by the end of 2008. Novel radionuclides or radionuclides of current limited availability have been selected according to the following criteria: emission of positrons, low-energy beta or alpha particles, stable or short half-life daughters, half-life between 3 h and 10 days or generator-produced, favourable dosimetry, production from stable isotopes with reasonable cross sections. Three radionuclides appear well suited to targeted radionuclide therapy using beta ( 67 Cu, 47 Sc) or alpha ( 211 At) particles. Positron emitters allowing dosimetry studies prior to radionuclide therapy ( 64 Cu, 124 I, 44 Sc), or that can be generator-produced ( 82 Rb, 68 Ga) or providing the opportunity of a new imaging modality ( 44 Sc) are considered to have a great interest at short term whereas 86 Y, 52 Fe, 55 Co, 76 Br or 89 Zr are considered to have a potential interest at middle term. Several radionuclides not currently used in routine nuclear medicine or not available in sufficient amount for clinical research have been selected for future production. High-energy, high-intensity cyclotrons are necessary to produce some of the selected radionuclides and make possible future clinical developments in nuclear medicine. Associated with appropriate carriers, these radionuclides will respond to a maximum of unmet clinical needs. (orig.) 5

Maintaining high precision of isotope ratio analysis over extended periods of time.

Science.gov (United States)

Brand, Willi A

2009-06-01

Stable isotope ratios are reliable and long lasting process tracers. In order to compare data from different locations or different sampling times at a high level of precision, a measurement strategy must include reliable traceability to an international stable isotope scale via a reference material (RM). Since these international RMs are available in low quantities only, we have developed our own analysis schemes involving laboratory working RM. In addition, quality assurance RMs are used to control the long-term performance of the delta-value assignments. The analysis schemes allow the construction of quality assurance performance charts over years of operation. In this contribution, the performance of three typical techniques established in IsoLab at the MPI-BGC in Jena is discussed. The techniques are (1) isotope ratio mass spectrometry with an elemental analyser for delta(15)N and delta(13)C analysis of bulk (organic) material, (2) high precision delta(13)C and delta(18)O analysis of CO(2) in clean-air samples, and (3) stable isotope analysis of water samples using a high-temperature reaction with carbon. In addition, reference strategies on a laser ablation system for high spatial resolution delta(13)C analysis in tree rings is exemplified briefly.

On hierarchy in asymptotic reconstruction of spontaneously broken isotopic symmetry

International Nuclear Information System (INIS)

Ermolaev, B.I.

1978-01-01

The isotopic features of the effective current-current lagrangian of the Lsub(eff) electromagnetic-weak interaction between elementary particles are treated at large momentum transfers using the Weinberg-Salam model. Transition to other models may be made by analogy. It is shown that when the collision energies of elementary particles exceed 90 GeV one may expect the hierarchy in the asymptotic reconstruction of the isotopic symmetry. Such hierarchy could be observed, in particular, in experiments on elastic leptonic collisions at high energies

Lessons learned form high-flux isotope reactor restart efforts

International Nuclear Information System (INIS)

Dahl, T.L.

1989-01-01

When the high-flux isotope reactor's (HFIR's) pressure vessel irradiation surveillance specimens were examined in December 1986, unexpected embrittlement was found. The resulting investigation disclosed widespread deficiencies in quality assurance and management practices. On March 24, 1987, the US Department of Energy (DOE) mandated a shutdown of all five Oak Ridge National Laboratory (ORNL) research reactors. Since the beginning of 1987, 18 different formal review groups have evaluated the management and operations of the HFIR. The root cause of the identified deficiencies in the HFIR program was defined as a lack of rigor in management practices and complacency built on twenty years of trouble-free operation. A number of lessons can be learned from the HFIR experience. Particular insight can be gained by comparing the HFIR organization prior to the shutdown with the organization that exists today. Key elements in such a comparison include staffing, funding, discipline, and formality in operations, maintenance, and management

Isotope production and distribution Programs Fiscal Year (FY) 1995 Financial Statement Audit (ER-FC-96-01)

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-02-12

The charter of the Department of Energy (DOE) Isotope Production and Distribution Program (Isotope Program) covers the production and sale of radioactive and stable isotopes, associated byproducts, surplus materials such as lithium and deuterium, and related isotope services. Services provided include, but are not limited to, irradiation services, target preparation and processing, source encapsulation and other special preparations, analyses, chemical separations, and leasing of stable isotopes for research purposes. Isotope Program products and services are sold worldwide for use in a wide variety of research, development, biomedical, and industrial applications. The Isotope Program reports to the Director of the Office of Nuclear Energy, Science and Technology. The Isotope Program operates under a revolving fund, as established by the Fiscal Year 1990 Energy and Water Appropriations Act (Public Law 101-101). The Fiscal Year 1995 Appropriations Act (Public Law 103-316) modified predecessor acts to allow prices charged for Isotope Program products and services to be based on production costs, market value, the needs of the research community, and other factors. Prices set for small-volume, high-cost isotopes that are needed for research may not achieve full-cost recovery. Isotope Program costs are financed by revenues from the sale of isotopes and associated services and through payments from the isotope support decision unit, which was established in the DOE fiscal year 1995 Energy, Supply, Research, and Development appropriation. The isotope decision unit finances the production and processing of unprofitable isotopes that are vital to the national interest.

High-spin studies and nuclear structure in three semi-magic regions of the chart: High-seniority states in Sn isotopes

International Nuclear Information System (INIS)

Astier, A.

2013-01-01

Two fusion-fission experiments have been performed and studied with the Euroball Ge array: 12 C+ 238 U at 90 MeV bombarding energy, and 18 O + 208 Pb at 85 MeV. Among the lot of new information extracted during the last decade, the latest results discussed here are the discovery of the high-spin states of 119-126 Sn. The maximum value of angular momentum available in the Vh 11/2 shell, i.e. for mid-occupation and the breaking of the three neutron pairs (seniority v = 6), has been identified in several tin isotopes. It is the first time that such high-seniority states are established in spherical nuclei. (authors)

Electromagnetic separation of stable isotopes at the Institute of Atomic Energy, Academia Sinica

International Nuclear Information System (INIS)

Hua, M.; Li, G.; Su, S.; Mao, N.; Lu, H.

1981-01-01

For almost 20 years the Institute of Atomic Energy, Academia Sinica has been separating stable isotopes of the elements by electromagnetic separators and supplying these materials to research work in many fields of our country. In this article we shall attempt to outline the growth of the effort and describe the present situation. (orig.)

Influence of Biofield Energy Treatment on Isotopic Abundance Ratio in Aniline Derivatives

OpenAIRE

Nayak, Gopal; Trivedi, Mahendra Kumar; Trivedi, Dahryn; Branton, Alice

2015-01-01

The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of 13C/12C or 2H/1H or 15N/14N ≡ (PM+1)/PM in aniline; and (PM+1)/PM and 81Br/79Br ≡ (PM+2)/PM in 4-bromoaniline using Gas Chromatography-Mass Spectrometry (GC-MS). Aniline and 4-bromoaniline samples were divided into two parts: control and treated. The control part remained as untreated, while the treated part was subjected to Mr. Trivedi’s biofield energy treatment. The treated samples we...

Influence of Biofield Energy Treatment on Isotopic Abundance Ratio in Aniline Derivatives

OpenAIRE

Trivedi , Mahendra Kumar; Branton , Alice; Trivedi , Dahryn; Nayak , Gopal; Saikia , Gunin; Jana , Snehasis

2015-01-01

International audience; The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of 13C/12C or 2H/1H or 15N/14N ≡ (PM+1)/PM in aniline; and (PM+1)/PM and 81Br/79Br ≡ (PM+2)/PM in 4-bromoaniline using Gas Chromatography-Mass Spectrometry (GC-MS). Aniline and 4-bromoaniline samples were divided into two parts: control and treated. The control part remained as untreated, while the treated part was subjected to Mr. Trivedi’s biofield energy treatment...

Influence of Biofield Energy Treatment on Isotopic Abundance Ratio in Aniline Derivatives

OpenAIRE

Mahendra, Trivedi; Alice, Branton; Dahryn, Trivedi; Gopal, Nayak

2015-01-01

The aim of this study was to evaluate the impact of biofield energy treatment on the isotopic abundance of 13C/12C or 2H/1H or 15N/14N ≡ (PM+1)/PM in aniline; and (PM+1)/PM and 81Br/79Br ≡ (PM+2)/PM in 4-bromoaniline using Gas Chromatography-Mass Spectrometry (GC-MS). Aniline and 4-bromoaniline samples were divided into two parts: control and treated. The control part remained as untreated, while the treated part was subjected to Mr. Trivedi's biofield energy treatment. The treated samples we...

Isotope shifts and electronic configurations of some of the energy levels of the neutral gadolinium atom

International Nuclear Information System (INIS)

Ahmad, S.A.; Venugopalan, A.; Saksena, G.D.

1982-01-01

Isotope shift ΔT (156-160) have been evaluated for 52 odd and 90 even energy levels of the neutral gadolinium atom from the measurements carried out on 166 lines of the first spectrum in the region 4535 to 4975 A on a photoelectric recording Fabry-Perot Spectrometer and enriched samples of 156 Gd and 160 Gd. Earlier studies provide data for just two lines in this region. Assignment of electronic configurations to some of the energy levels have been either confirmed or revised; some unassigned levels have been assigned probable configurations. The present study provides, for the first time, isotope shift of the two levels of 4f 7 6s 2 7s configuration of Gd I. (author)

Isotope-beam modification of materials at eV energies

International Nuclear Information System (INIS)

Krug, C.; Radtke, C.; Stedile, F.C.; Baumvol, I.J.R.

2001-01-01

We developed a low energy ion beam deposition system for isotope-selective modification of materials. It consists of a conventional ion implanter (HVEE 500 kV) and an attachable deceleration system. 29 (N 2 ) + ion beams were used for the nitridation of Si(0 0 1) and the resulting 15 N retained doses and profiles were determined by narrow nuclear resonance profiling. 29 Si was deposited on amorphous carbon films on Si(0 0 1) and the doses evaluated by channeled α particle beams with detection of scattered α at grazing angles. 29 Si was also deposited on Si(0 0 1) and the resulting profiles determined by narrow nuclear resonance

The Gd-isotopic fuel for high burnup in PWR's

International Nuclear Information System (INIS)

Dias, Marcio Soares; Mattos, João Roberto L. de; Andrade, Edison Pereira de

2017-01-01

Today, the discussion about the high burnup fuel is beyond the current fuel enrichment licensing and burnup limits. Licensing issues and material/design developments are again key features in further development of the LWR fuel design. Nevertheless, technological and economical solutions are already available or will be available in a short time. In order to prevent the growth of the technological gap, Brazil's nuclear sector needs to invest in the training of new human resources, in the access to international databases, and in the upgrading existing infrastructure. Experimental database and R&D infrastructure are essential components to support the autonomous development of Brazilian Nuclear Reactors, promoting the development of national technologies. The (U,Gd)O_2 isotopic fuel proposed by the CDTN's staff solve two main issues in the high burnup fuel, which are (1) the peak of reactivity resulting from the Gd-157 fast burnup, and (2) the peak of temperature in the (U,Gd)O_2 nuclear fuel resulting from detrimental effects in the thermal properties for gadolinia additions higher than 2%. A sustainable future can be envisaged for the nuclear energy. (author)

Proceedings of the third specialists` meeting on high energy nuclear data

Energy Technology Data Exchange (ETDEWEB)

Fukahori, Tokio [ed.

1998-11-01

This report is the Proceedings of the Third Specialists` Meeting on High Energy Nuclear Data. The meeting was held on March 30-31, 1998, at the Tokai Research Establishment of Japan Atomic Energy Research Institute with the participation of forty-odd specialists, who were the evaluators, theorists, experimentalists and users of high energy nuclear data including the members of the Japanese Nuclear Data Committee. The need of the high energy nuclear data up to a few Gev has been stressed in the meeting for many applications, such as spallation neutron sources for radioactive waste treatment, accelerator shielding design, medical isotope production, radiation therapy, the effects of space radiation on astronauts and their equipments, and the cosmic history of meteorites and other galactic substances. Since the Second Specialists` Meeting in 1995, such an evaluation activity in Japan has been grown and the results are accumulated. Foreign activities of high energy nuclear data evaluation are also being increased. According to the above situation, with the view point of reviewing and validating an evaluated high energy nuclear data file, project of high energy nuclear data file production, differential and integral experiments, status of evaluation and reviewing methods, processing and transport calculation methods, benchmark tests, international trends, etc. were discussed. The 16 of the presented papers are indexed individually. (J.P.N.)

Radio-isotope production using laser Wakefield accelerators

International Nuclear Information System (INIS)

Leemans, W.P.; Rodgers, D.; Catravas, P.E.; Geddes, C.G.R.; Fubiani, G.; Toth, C.; Esarey, E.; Shadwick, B.A.; Donahue, R.; Smith, A.; Reitsma, A.

2001-01-01

A 10 Hz, 10 TW solid state laser system has been used to produce electron beams suitable for radio-isotope production. The laser beam was focused using a 30 cm focal length f/6 off-axis parabola on a gas plume produced by a high pressure pulsed gas jet. Electrons were trapped and accelerated by high gradient wakefields excited in the ionized gas through the self-modulated laser wakefield instability. The electron beam was measured to contain excesses of 5 nC/bunch. A composite Pb/Cu target was used to convert the electron beam into gamma rays which subsequently produced radio-isotopes through (gamma, n) reactions. Isotope identification through gamma-ray spectroscopy and half-life time measurements demonstrated that Cu 61 was produced which indicates that 20-25 MeV gamma rays were produced, and hence electrons with energies greater than 25-30 MeV. The production of high energy electrons was independently confirmed using a bending magnet spectrometer. The measured spectra had an exponential distribution with a 3 MeV width. The amount of activation was on the order of 2.5 uCi after 3 hours of operation at 1 Hz. Future experiments will aim at increasing this yield by post-accelerating the electron beam using a channel guided laser wakefield accelerator

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

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

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

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

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

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

Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution recovery image reconstruction. The

Fe-O stable isotope pairs elucidate a high-temperature origin of Chilean iron oxide-apatite deposits

Science.gov (United States)

Bilenker, Laura D.; Simon, Adam C.; Reich, Martin; Lundstrom, Craig C.; Gajos, Norbert; Bindeman, Ilya; Barra, Fernando; Munizaga, Rodrigo

2016-03-01

Iron oxide-apatite (IOA) ore deposits occur globally and can host millions to billions of tons of Fe in addition to economic reserves of other metals such as rare earth elements, which are critical for the expected growth of technology and renewable energy resources. In this study, we pair the stable Fe and O isotope compositions of magnetite samples from several IOA deposits to constrain the source reservoir of these elements in IOAs. Since magnetite constitutes up to 90 modal% of many IOAs, identifying the source of Fe and O within the magnetite may elucidate high-temperature and/or lower-temperature processes responsible for their formation. Here, we focus on the world-class Los Colorados IOA in the Chilean iron belt (CIB), and present data for magnetite from other Fe oxide deposits in the CIB (El Laco, Mariela). We also report Fe and O isotopic values for other IOA deposits, including Mineville, New York (USA) and the type locale, Kiruna (Sweden). The ranges of Fe isotopic composition (δ56Fe, 56Fe/54Fe relative to IRMM-14) of magnetite from the Chilean deposits are: Los Colorados, δ56Fe (±2σ) = 0.08 ± 0.03‰ to 0.24 ± 0.08‰; El Laco, δ56Fe = 0.20 ± 0.03‰ to 0.53 ± 0.03‰; Mariela, δ56Fe = 0.13 ± 0.03‰. The O isotopic composition (δ18O, 18O/16O relative to VSMOW) of the same Chilean magnetite samples are: Los Colorados, δ18O (±2σ) = 1.92 ± 0.08‰ to 3.17 ± 0.03‰; El Laco, δ18O = 4.00 ± 0.10‰ to 4.34 ± 0.10‰; Mariela, δ18O = (1.48 ± 0.04‰). The δ18O and δ56Fe values for Kiruna magnetite yield an average of 1.76 ± 0.25‰ and 0.16 ± 0.07‰, respectively. The Fe and O isotope data from the Chilean IOAs fit unequivocally within the range of magnetite formed by high-temperature magmatic or magmatic-hydrothermal processes (i.e., δ56Fe 0.06-0.49‰ and δ18O = 1.0-4.5‰), consistent with a high-temperature origin for Chilean IOA deposits. Additionally, minimum formation temperatures calculated by using the measured Δ18O

Rare isotope beam energy measurements and scintillator developments for ReA3

Science.gov (United States)

Lin, Ling-Ying

The ReAccelerator for 3 MeV/u beams (ReA3) at the National Superconducting Cyclotron Laboratory (NSCL) in Michigan State University can stop rare isotope beams produced by in-flight fragmentation and reaccelerate them in a superconducting linac. The precise knowledge of the energy and the energy spread of the ion beams extracted from the ReA3 linac is essential for experimental requirement in many applications. Beam energy determination methods such as implantation on a Si detector and/or using calibrated linac settings are precise within a few tens of keV/u. In order to determine beam energies with good resolution of less than 0.5 % FWHM, a 45 degree bending magnet with a movable slit is used to determine the absolute beam energy based on the magnetic rigidity. Two methods have been developed for the energy calibration of the beam analyzing magnet: gamma-ray nuclear resonance reactions and a time-of-flight (TOF) technique. The resonance energies of gamma-ray resonant reactions provide well-known and precise calibration points. The gamma ray yields of the 27Al(p,gamma)28Si at Ep= 992 keV and 632 keV resonances and 58Ni(p,gamma)59Cu at Ep= 1843 keV resonance have been measured with the high efficiency CAESAR (CAESium iodide ARray) and SuN (Summing NaI(Tl)) detectors. By fitting the observed resonant gamma-ray yields, not only the beam energy can be precisely correlated with the magnetic field but also beam energy spread can be obtained. The measured beam energy spread is consistent with beam optics calculations. A time-of-flight system for determining the absolute energy of ion beams and calibrating the 45 degree magnetic analyzer has been developed in ReA3 by using two identical secondary electron monitors (grid-MCP detectors) with appropriate separation. The TOF technique is applicable to the variety of beam energies and ion particles. Velocities of ion beam are determined by simultaneously measuring the arrival time of beam bunches at the two detectors with

Heavy ion reactions at high energies

International Nuclear Information System (INIS)

Jakobsson, Bo.

1977-01-01

A review on heavy ion experiments at energies >0.1GeV/nucleon is presented. Reaction cross-sections, isotope production cross-sections and pion production in nucleus-nucleus collisions are discussed. Some recent models for heavy ion reactions like the abrasion-ablation model, the fireball model and the different shock-wave models are also presented

Laser spectroscopy and laser isotope separation of atomic gadolinium

International Nuclear Information System (INIS)

Chen, Y. W.; Yamanaka, C.; Nomaru, K.; Kou, K.; Niki, H.; Izawa, Y.; Nakai, S.

1994-01-01

Atomic vapor laser isotope separation (AVLIS) is a process which uses intense pulsed lasers to selectively photoionize one isotopic species of a chemical element, after which these ions are extracted electromagnetically. The AVLIS has several advantages over the traditional methods based on the mass difference, such as high selectivity, low energy consumption, short starting time and versatility to any atoms. The efforts for atomic vapor laser isotope separation at ILT and ILE, Osaka University have been concentrated into the following items: 1) studies on laser spectroscopy and laser isotope separation of atomic gadolinium, 2) studies on interaction processes including coherent dynamics, propagation effects and atom-ion collision in AVLIS system, 3) development of laser systems for AVLIS. In this paper, we present experimental results on the laser spectroscopy and laser isotope separation of atomic gadolinium.

Isotope effect with energy-dependent density of states and impurities

International Nuclear Information System (INIS)

Williams, P.J.; Carbotte, J.P.

1992-01-01

We have calculated the total isotope coefficient β in a model where there is energy-dependent structure in the electronic density of states. We model the structure with a simple Lorentzian. In our calculation, doping has the effect of shifting the Fermi level and broadening the structure in the density of states. We have treated the dopants both as normal and as magnetic impurities. The asymmetry observed in the experimental data is found in our results. However, the complete range of values observed is difficult to reproduce. We question also whether the shifts in Fermi level required in such models are reasonable

Diffusion of transmutation isotope in YBaCuO ceramics

International Nuclear Information System (INIS)

Malkovich, R.Sh.

2005-01-01

The diffusion of a transmutation isotope generated in YBaCuO ceramics irradiated by high-energy charged particles is mathematically analyzed. The model is based on the assumption that copper isotope atoms created in subsurface layers of ceramic grains segregate at the grain boundaries in the course of subsequent annealing and then rapidly diffuse via intergranular regions in depth of the material and penetrate into the bulk of grains [ru

Calculation of radiation production of high specific activity isotopes 192Ir and 60Co

International Nuclear Information System (INIS)

Zhou Quan; Zhong Wenfa; Xu Xiaolin

1997-01-01

The high specific activity isotopes: 192 Ir and 60 Co in the high neutron flux reactor are calculated with the method of reactor physics. The results of calculation are analyzed in two aspects: the production of isotopes and the influence to parameters of the reactor, and hence a better case is proposed as a reference to the production

High Flux Isotope Reactor power upgrade status

International Nuclear Information System (INIS)

Rothrock, R.B.; Hale, R.E.; Cheverton, R.D.

1997-01-01

A return to 100-MW operation is being planned for the High Flux Isotope Reactor (HFIR). Recent improvements in fuel element manufacturing procedures and inspection equipment will be exploited to reduce hot spot and hot streak factors sufficiently to permit the power upgrade without an increase in primary coolant pressure. Fresh fuel elements already fabricated for future use are being evaluated individually for power upgrade potential based on their measured coolant channel dimensions

Coupled thermochemical, isotopic evolution and heat transfer simulations in highly irradiated UO{sub 2} nuclear fuel

Energy Technology Data Exchange (ETDEWEB)

Piro, M.H.A., E-mail: markuspiro@gmail.com [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Banfield, J. [Nuclear Engineering Department, University of Tennessee, Knoxville, TN (United States); Clarno, K.T., E-mail: clarnokt@ornl.gov [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Simunovic, S. [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Besmann, T.M. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Lewis, B.J.; Thompson, W.T. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON (Canada)

2013-10-15

Predictive capabilities for simulating irradiated nuclear fuel behavior are enhanced in the current work by coupling thermochemistry, isotopic evolution and heat transfer. Thermodynamic models that are incorporated into this framework not only predict the departure from stoichiometry of UO{sub 2}, but also consider dissolved fission and activation products in the fluorite oxide phase, noble metal inclusions, secondary oxides including uranates, zirconates, molybdates and the gas phase. Thermochemical computations utilize the spatial and temporal evolution of the fission and activation product inventory in the pellet, which is typically neglected in nuclear fuel performance simulations. Isotopic computations encompass the depletion, decay and transmutation of more than 2000 isotopes that are calculated at every point in space and time. These computations take into consideration neutron flux depression and the increased production of fissile plutonium near the fuel pellet periphery (i.e., the so-called “rim effect”). Thermochemical and isotopic predictions are in very good agreement with reported experimental measurements of highly irradiated UO{sub 2} fuel with an average burnup of 102 GW d t(U){sup −1}. Simulation results demonstrate that predictions are considerably enhanced when coupling thermochemical and isotopic computations in comparison to empirical correlations. Notice: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

Local transport in Joint European Tokamak edge-localized, high-confinement mode plasmas with H, D, DT, and T isotopes

International Nuclear Information System (INIS)

Budny, R. V.; Ernst, D. R.; Hahm, T. S.; McCune, D. C.; Christiansen, J. P.; Cordey, J. G.; Gowers, C. G.; Guenther, K.; Hawkes, N.; Jarvis, O. N.

2000-01-01

The edge-localized, high-confinement mode regime is of interest for future Tokamak reactors since high performance has been sustained for long durations. Experiments in the Joint European Tokamak [M. Keilhacker , Nuclear Fusion 39, 209 (1999)] have studied this regime using scans with the toroidal field and plasma current varied together in H, D, DT, and T isotopes. The local energy transport in more than fifty of these plasmas is analyzed, and empirical scaling relations are derived for energy transport coefficients during quasi-steady state conditions using dimensionless parameters. Neither the Bohm nor gyro-Bohm expressions give the shapes of the profiles. The scalings with β and ν * are in qualitative agreement with Ion Temperature Gradient theory

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

Hydrocarbon isotope detection by elastic peak electron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Kostanovskiy, I.A., E-mail: kostanovskiyia@gmail.com [National Research University MPEI, Krasnokazarmennaya 14, 111250 Moscow (Russian Federation); Afanas’ev, V.P. [National Research University MPEI, Krasnokazarmennaya 14, 111250 Moscow (Russian Federation); Naujoks, D. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstraße 1, D-17491 Greifswald (Germany); Mayer, M. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany)

2015-07-15

Highlights: • PCVD hydrocarbon coatings containing protium or deuterium are analyzed via NRA, ERD, XPS and EPES. • EPES analysis with modern electron energy analyzer SPECS Phoibos 225 shows a clear signal from the hydrogen isotopes. • Different primary energies and scattering angles help to quantify isotope content from EPES spectra. - Abstract: Experimental results on the hydrocarbon isotope analysis by elastic peak electron spectroscopy are presented. Amorphous hydrocarbon samples (a-C:H, a-C:D) are prepared by PCVD and analyzed by nuclear reaction analysis (NRA), elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES). Electron energy spectra show a clear signal from the hydrogen isotopes deuterium and protium. Different incident energies and scattering geometries help to resolve plasmon and elastic energy losses.

Hydrocarbon isotope detection by elastic peak electron spectroscopy

International Nuclear Information System (INIS)

Kostanovskiy, I.A.; Afanas’ev, V.P.; Naujoks, D.; Mayer, M.

2015-01-01

Highlights: • PCVD hydrocarbon coatings containing protium or deuterium are analyzed via NRA, ERD, XPS and EPES. • EPES analysis with modern electron energy analyzer SPECS Phoibos 225 shows a clear signal from the hydrogen isotopes. • Different primary energies and scattering angles help to quantify isotope content from EPES spectra. - Abstract: Experimental results on the hydrocarbon isotope analysis by elastic peak electron spectroscopy are presented. Amorphous hydrocarbon samples (a-C:H, a-C:D) are prepared by PCVD and analyzed by nuclear reaction analysis (NRA), elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES). Electron energy spectra show a clear signal from the hydrogen isotopes deuterium and protium. Different incident energies and scattering geometries help to resolve plasmon and elastic energy losses

High precision analysis of trace lithium isotope by thermal ionization mass spectrometry

International Nuclear Information System (INIS)

Tang Lei; Liu Xuemei; Long Kaiming; Liu Zhao; Yang Tianli

2010-01-01

High precision analysis method of ng lithium by thermal ionization mass spectrometry is developed. By double-filament measurement,phosphine acid ion enhancer and sample pre-baking technique,the precision of trace lithium analysis is improved. For 100 ng lithium isotope standard sample, relative standard deviation is better than 0.086%; for 10 ng lithium isotope standard sample, relative standard deviation is better than 0.90%. (authors)

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

Temperature Dependent Surface Modification of Tungsten Exposed to High-Flux Low-Energy Helium Ion Irradiation

OpenAIRE

Damico, Antony Q; Tripathi, Jitendra K; Novakowski, Theodore J; Miloshevsky, Gennady; Hassanein, Ahmed

2016-01-01

Nuclear fusion is a great potential energy source that can provide a relatively safe and clean limitless supply of energy using hydrogen isotopes as fuel material. ITER (international thermonuclear experimental reactor) is the world first fusion reactor currently being built in France. Tungsten (W) is a prime candidate material as plasma facing component (PFC) due to its excellent mechanical properties, high melting point, and low erosion rate. However, W undergoes a severe surface morphology...

Calculation of relativistic and isotope shifts in Mg I

International Nuclear Information System (INIS)

Berengut, J.C.; Flambaum, V.V.; Kozlov, M.G.

2005-01-01

We present an ab initio method of calculation of the isotope and relativistic shifts in atoms with a few valence electrons. It is based on an energy calculation involving the combination of the configuration-interaction method and many-body perturbation theory. This work is motivated by analyses of quasar absorption spectra that suggest that the fine-structure constant α was smaller at an early epoch. Relativistic shifts are needed to measure this variation of α, while isotope shifts are needed to resolve systematic effects in this study. The isotope shifts can also be used to measure isotopic abundances in gas clouds in the early universe, which are needed to study nuclear reactions in stars and supernovae and test models of chemical evolution. This paper shows that the isotope shift in magnesium can be calculated to very high precision using our method

Influence of Three-square-well Interaction Potential on Isotope Effect Coefficient of High-TC Superconductors

International Nuclear Information System (INIS)

Udomsamuthirun, P.; Dokkaemklang, S.; Kumvongsa, C.; Maneeratanakul, S.

2005-10-01

In this research, the exact formula of the isotope effect coefficient of s wave and d-wave superconductor in weak-coupling limit are derived by using a three square- well interaction potential that pairing interaction consists of 3 parts : an attractive electron-phonon interaction, an attractive non-electron-phonon interaction , and a repulsive Coulomb interaction . op ac , w w and c w is the characteristic energy cutoff of the Debye phonon , non-phonon ,and Coulomb respectively and 2 / 1 ac M- a w , and c op , w w do not depend on isotope mass(M). We find that, in all case of consideration, the isotope coefficient converges to 0.5 at lower value of Coulomb coupling constant and larger values of phonon and non-phonon coupling constant

Isotopically Enriched C-13 Diamond Anvil as a Stress Sensor in High Pressure Experiments

Science.gov (United States)

Vohra, Yogesh; Qiu, Wei; Kondratyev, Andreiy; Velisavljevic, Nenad; Baker, Paul

2004-03-01

The conventional high pressure diamond anvils were modified by growing an isotopically pure C-13 diamond layer by microwave plasma chemical vapor deposition using methane/hydrogen/oxygen chemistry. The isotopically pure C-13 nature of the culet of the diamond anvil was confirmed by the Raman spectroscopy measurements. This isotopically engineered diamond anvil was used against a natural abundance diamond anvil for high pressure experiments in a diamond anvil cell. Spatial resolved Raman spectroscopy was used to measure the stress induced shift in the C-13 layer as well as the undelying C-12 layer to ultra high pressures. The observed shift and splitiing of the diamond first order Raman spectrum was correlated with the stress distribution in the diamond anvil cell. The experimental results will be compared with the finite element modeling results using NIKE-2D software in order to create a mathematical relationship between sets of the following parameters: vertical (z axis) distance; horizontal (r axis) distance; max shear stress, and pressure. The isotopically enriched diamond anvils offer unique opportunities to measure stress distribution in the diamond anvil cell devices.

Laser isotope separation - a new class of chemical process

International Nuclear Information System (INIS)

Woodall, K.B.; Mannik, L.; O'Neill, J.A.; Mader, D.L.; Nickerson, S.B.; Robins, J.R.; Bartoszek, F.E.; Gratton, D.

1983-01-01

Lasers may soon find several applications in chemical processing. The applications that have attracted the most research funding to date involve isotope separation for the nuclear industry. These isotopes have an unusually high value (≥$1000/kg) compared to bulk chemicals (∼$1/kg) and are generally required in very large quantities. In a laser isotope separation process, light is used to convert a separation that is very difficult or even impossible by conventional chemical engineering techniques to one that is readily handled by conventional separation technology. For some isotopes this can result in substantial capital and energy savings. A uranium enrichment process developed at the Lawrence Livermore National Laboratory is the closest to commercialization of the large scale laser isotope separation processes. Of particular interest to the Canadian nuclear industry are the laser separation of deuterium, tritium, zirconium-90 and carbon-14. In this paper, the basic principles behind laser isotope separation are reviewed and brief dscriptions of the more developed processes are given

Effect of isotopic substitution on the collisional quenching of vibronically excited CO+

International Nuclear Information System (INIS)

Katayama, D.H.; Welsh, J.A.

1983-01-01

Rovibronic levels of the A 2 Pi/sub i/ state for 12 C 16 O + and 13 C 16 O + have been selectively excited by a pulsed, tunable dye laser and their time resolved fluorescence obtained as a function of helium pressure. These ions are formed by reaction of neutral carbon monoxide with helium metastable atoms created in a dc discharge. Since 13 CO + has essentially the same potential energy curves as 12 CO + , but differs primarily in its vibrational energy spacings, this experiment accentuates the role, in the collisional deactivation process, of the high lying ground state vibrational levels which are adjacent to the laser populated vibronic levels of the A 2 Pi/sub i/ state. Quenching rates are determined for the v' = 0, 1, and 2 levels which have relatively insignificant isotope shifts of a few wave numbers for the two isotopes. The difference in rates for the two isotopic ions demonstrates the importance of the positions for the high lying v'' = 10 and 11 ground state levels which have large isotope shifts of hundreds of wave numbers. A discussion of the deactivation process is given in terms of perturbations, Franck--Condon factors, energy gaps, and other considerations

Isotope effect on the zero point energy shift upon condensation. I. Formulation and application to ethylene, methane, and fluoromethanes

International Nuclear Information System (INIS)

Kornblum, Z.C.; Ishida, T.

1978-01-01

A method of evaluating the isotope effect (IE) on the zero point energy (ZPE) shift upon condensation due to the London dispersion forces in the liquid has been formulated. It is expressed to the first order, as a product of an isotope-independent liquid factor and a factor of isotopic differences in gas-phase properties. The theory has been tested by calculating the effective atomic charges for carbon and hydrogen in ethylene, according to the CNDO/2 molecular orbital algorithm, and it correctly predicts the magnitude of the IE on the ZPE shift and the first-order sum rules involving the isotopic ethylenes. However, it fails to explain the difference in vapor pressures of isotopic isomers. The theory has also been applied to the D/H and to the 13 C/ 12 C isotope effects in methane and fluoromethanes. The results obtained from the CNDO/2 calculations have been compared with the experimental values of the total infrared absorption intensities and of the IE on the ZPE shift of isotopic methanes. Based on these calculations, the molecular properties that enhance the stronger dispersion forces in the liquid phase between the lighter molecules than between the isotopically heavier molecules, and hence favor a large IE on the ZPE shift, have been deduced

Spectrum analysis in lead spectrometer for isotopic fissile assay in used fuel

International Nuclear Information System (INIS)

Lee, Y.D.; Park, C.J.; Kim, H.D.; Song, K.C.

2014-01-01

The LSDS system is under development for analyzing isotopic fissile content applicable in a hot cell for the pyro process. The fuel assay area and nuclear material composition were selected for simulation. The source mechanism for efficient neutron generation was also determined. A neutron is produced at the Ta target by hitting it from accelerated electron. The parameters for an electron accelerator are being researched for cost effectiveness, easy maintenance, and compact size. The basic principle of LSDS is that isotopic fissile has its own fission structure below the unresolved resonance region. The source neutron interacts with a lead medium and produces continuous neutron energy, which generates dominant fission at each fissile. Therefore, a spectrum analysis is very important at a lead medium and fuel area for system working. The energy spectrum with respect to slowing down energy and the energy resolution were investigated in lead. A spectrum analysis was done by the existence of surrounding detectors. In particular, high resonance energy was considered. The spectrum was well organized at each slowing down energy and the energy resolution was acceptable to distinguish isotopic fissile fissions. Additionally, LSDS is applicable for the optimum design of spent fuel storage and management.The isotopic fissile content assay will increase the transparency and credibility for spent fuel storage and its re-utilization, as demanded internationally. (author)

Gas phase adsorption technology for nitrogen isotope separation and its feasibility for highly enriched nitrogen gas production

International Nuclear Information System (INIS)

Inoue, Masaki; Asaga, Takeo

2000-04-01

Highly enriched nitrogen-15 gas is favorable to reduce radioactive carbon-14 production in reactor. The cost of highly enriched nitrogen-15 gas in mass production is one of the most important subject in nitride fuel option in 'Feasibility Study for FBR and Related Fuel Cycle'. In this work gas phase adsorption technology was verified to be applicable for nitrogen isotope separation and feasible to produce highly enriched nitrogen-15 gas in commercial. Nitrogen isotopes were separated while ammonia gas flows through sodium-A type zeolite column using pressure swing adsorption process. The isotopic ratio of eight samples were measured by high resolution mass spectrometry and Fourier transform microwave spectroscopy. Gas phase adsorption technology was verified to be applicable for nitrogen isotope separation, since the isotopic ratio of nitrogen-15 and nitrogen-14 in samples were more than six times as high as in natural. The cost of highly enriched nitrogen-15 gas in mass production were estimated by the factor method. It revealed that highly enriched nitrogen-15 gas could be supplied in a few hundred yen per gram in mass production. (author)

Isotope effects of sulfur in chemical reactions

International Nuclear Information System (INIS)

Mikolajczuk, A.

1999-01-01

Sulfur is an important component of organic matter because it forms compounds with many elements. Due to high chemical activity of sulfur, it takes part in biological and geological processes in which isotope effects are occurring. It has been shown during last years research of isotope effects that we have take into account not only mass difference but also many other physical properties of nuclides e.g. even or odd number of neutrons in nuclei, shape and distribution of charge, turn of nuclear spin etc. The factor remains that new theoretical ideas have been formed on the base of data, being obtained in fractionation processes of heavy element isotope, particularly uranium. Now it is being well known that effects unconnected with vibration energy have also caused an effect on fractionation of considerably lighter elements like iron and magnesium. The important question is, if these effects would come to light during the separation of sulfur isotopes. Sulfur have three even isotopes M = (32, 34, 36) and one odd M 33). This problem is still open. (author)

Melting point of high-purity germanium stable isotopes

Science.gov (United States)

Gavva, V. A.; Bulanov, A. D.; Kut'in, A. M.; Plekhovich, A. D.; Churbanov, M. F.

2018-05-01

The melting point (Tm) of germanium stable isotopes 72Ge, 73Ge, 74Ge, 76Ge was determined by differential scanning calorimetry. With the increase in atomic mass of isotope the decrease in Tm is observed. The decrease was equal to 0.15 °C per the unit of atomic mass which qualitatively agrees with the value calculated by Lindemann formula accounting for the effect of "isotopic compression" of elementary cell.

Isotopic quantum correction to liquid methanol at -30 C

CERN Document Server

Benmore, C J; Egelstaff, P A; Neuefeind, J

2002-01-01

Hydrogen/deuterium (H/D) substitution of molecular liquids in neutron diffraction is a powerful tool for structure determination. However, recent high-energy X-ray studies have found observable differences in the structures of many H and D liquids at the same temperature. In some cases this isotopic quantum effect can be corrected for by measuring the D sample at a slightly different temperature to the H sample. The example of hydroxyl isotopic substitution in liquid methanol at -30 C is presented. The magnitude of the quantum effect is shown to be significant when compared to the size of the first-order isotopic neutron-difference function. (orig.)

High energy proton-induced radioactivity in HgI2 crystals

International Nuclear Information System (INIS)

Porras, E.; Ferrero, J.L.; Sanchez, F.; Ruiz, J.A.; Lei, F.

1995-01-01

Mercuric iodide (HgI 2 ) semiconductor crystals are generating a lot of interest as room temperature solid state detectors for hard X-ray astronomy observations. For these applications one of the most important background sources is the cosmic proton induced radioactivity in the detector material. In order to study this background noise contribution a 1x1x1 cm HgI 2 crystal was irradiated with high energy protons. The resulting long-lived unstable isotopes and their production rates have been identified and compared with Monte Carlo simulations. ((orig.))

Energy-Recovery Linacs for Commercial Radioisotope Production

International Nuclear Information System (INIS)

Johnson, Rolland Paul

2016-01-01

Most radioisotopes are produced by nuclear reactors or positive ion accelerators, which are expensive to construct and to operate. Photonuclear reactions using bremsstrahlung photon beams from less-expensive electron linacs can generate isotopes of critical interest, but much of the beam energy in a conventional electron linac is dumped at high energy, making unwanted radioactivation. The largest part of this radioactivation may be completely eliminated by applying energy recovery linac technology to the problem with an additional benefit that the energy cost to produce a given amount of isotope is reduced. Consequently, a Superconducting Radio Frequency (SRF) Energy Recovery Linac (ERL) is a path to a more diverse and reliable domestic supply of short-lived, high-value, high-demand isotopes at a cost lower than that of isotopes produced by reactors or positive-ion accelerators. A Jefferson Lab approach to this problem involves a thin photon production radiator, which allows the electron beam to recirculate through rf cavities so the beam energy can be recovered while the spent electrons are extracted and absorbed at a low enough energy to minimize unwanted radioactivation. The thicker isotope photoproduction target is not in the beam. MuPlus, with Jefferson Lab and Niowave, proposed to extend this ERL technology to the commercial world of radioisotope production. In Phase I we demonstrated that 1) the ERL advantage for producing radioisotopes is at high energies (~100 MeV), 2) the range of acceptable radiator thickness is narrow (too thin and there is no advantage relative to other methods and too thick means energy recovery is too difficult), 3) using optics techniques developed under an earlier STTR for collider low beta designs greatly improves the fraction of beam energy that can be recovered (patent pending), 4) many potentially useful radioisotopes can be made with this ERL technique that have never before been available in significant commercial quantities

Energy-Recovery Linacs for Commercial Radioisotope Production

Energy Technology Data Exchange (ETDEWEB)

Johnson, Rolland Paul [Muplus, Inc., Newport News, VA (United States)

2016-11-19

Most radioisotopes are produced by nuclear reactors or positive ion accelerators, which are expensive to construct and to operate. Photonuclear reactions using bremsstrahlung photon beams from less-expensive electron linacs can generate isotopes of critical interest, but much of the beam energy in a conventional electron linac is dumped at high energy, making unwanted radioactivation. The largest part of this radioactivation may be completely eliminated by applying energy recovery linac technology to the problem with an additional benefit that the energy cost to produce a given amount of isotope is reduced. Consequently, a Superconducting Radio Frequency (SRF) Energy Recovery Linac (ERL) is a path to a more diverse and reliable domestic supply of short-lived, high-value, high-demand isotopes at a cost lower than that of isotopes produced by reactors or positive-ion accelerators. A Jefferson Lab approach to this problem involves a thin photon production radiator, which allows the electron beam to recirculate through rf cavities so the beam energy can be recovered while the spent electrons are extracted and absorbed at a low enough energy to minimize unwanted radioactivation. The thicker isotope photoproduction target is not in the beam. MuPlus, with Jefferson Lab and Niowave, proposed to extend this ERL technology to the commercial world of radioisotope production. In Phase I we demonstrated that 1) the ERL advantage for producing radioisotopes is at high energies (~100 MeV), 2) the range of acceptable radiator thickness is narrow (too thin and there is no advantage relative to other methods and too thick means energy recovery is too difficult), 3) using optics techniques developed under an earlier STTR for collider low beta designs greatly improves the fraction of beam energy that can be recovered (patent pending), 4) many potentially useful radioisotopes can be made with this ERL technique that have never before been available in significant commercial quantities

High-resolution stratigraphy with strontium isotopes.

Science.gov (United States)

Depaolo, D J; Ingram, B L

1985-02-22

The isotopic ratio of strontium-87 to strontium-86 shows no detectable variation in present-day ocean water but changes slowly over millions of years. The strontium contained in carbonate shells of marine organisms records the ratio of strontium-87 to strontium-86 of the oceans at the time that the shells form. Sedimentary rocks composed of accumulated fossil carbonate shells can be dated and correlated with the use of high precision measurements of the ratio of strontium-87 to strontium-86 with a resolution that is similar to that of other techniques used in age correlation. This method may prove valuable for many geological, paleontological, paleooceanographic, and geochemical problems.

STRENGTH DISTRIBUTIONS IN NEODYMIUM ISOTOPES - A TEST OF COLLECTIVE NUCLEAR-MODELS

NARCIS (Netherlands)

PIGNANELLI, M; BLASI, N; BORDEWIJK, JA; DELEO, R; HARAKEH, MN; HOFSTEE, MA; MICHELETTI, S; PERRINO, R; PONOMAREV, VY; SOLOVIEV, VG; SUSHKOV, AV; VANDERWERF, SY

1993-01-01

Excite states n even N isotopes, up to excitation energies of 3-4 MeV, were investigate in proton- and deuteron-scattering experiments performed with high-energy resolution. More than 300 transitions were studied. For several new excited states spin and parity assignments have been suggested.

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

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

Excitation of high energy levels under laser exposure of suspensions of nanoparticles in liquids

Energy Technology Data Exchange (ETDEWEB)

Shafeev, G.A. [Wave Research Center of A.M. Prokhorov General Physics Institute, 38, Vavilov Street, 119991 Moscow (Russian Federation)], E-mail: shafeev@kapella.gpi.ru; Simakin, A.V. [Wave Research Center of A.M. Prokhorov General Physics Institute, 38, Vavilov Street, 119991 Moscow (Russian Federation); Bozon-Verduraz, F. [ITODYS, UMR CNRS 7086, Universite Paris 7-Denis Diderot, 2, place Jussieu, 75251 Paris cedex 05 (France); Robert, M. [Laboratoire d' Electrochimie Moleculaire, UMR CNRS 7591, Universite Paris 7 Denis Diderot, 2, place Jussieu, 75251 Paris cedex 05 (France)

2007-12-15

Laser exposure of suspensions of nanoparticles in liquids leads to excitation of high energy levels in both liquid and nanoparticle material. The emission spectrum of the colloidal solution under exposure of a suspension metallic nanoparticles in water to radiation of a Nd:YAG laser of a picosecond range of pulse duration is discussed. Excitation of nuclear energy levels and neutron release is experimentally studied on the model system of transmutation of Hg into Au that occurs under exposure of Hg nanodrops suspended in D{sub 2}O. The proposed mechanism involves: (i) emission of X-ray photons by Hg nanoparticles upon laser exposure, leading to neutron release from D{sub 2}O, (ii) initiation of Hg {yields} Au transmutation by the capture of neutrons. The effect of transmutation is more pronounced using {sup 196}Hg isotope instead of Hg of natural isotope composition. The influence of laser pulse duration on the degree of transmutation (from fs through ns range) is discussed.

Precision Measurement of the Energies and Line Shapes of Antiprotonic Lyman and Balmer Transitions From Hydrogen and Helium Isotopes

CERN Multimedia

2002-01-01

% PS207 \\\\ \\\\ For the study of the antiproton-proton and antiproton-nuclear spin-spin and spin-orbital interaction at threshold a high resolution measurement is proposed of the line shapes and energy shifts of antiprotonic K$\\alpha$ and L$\\alpha$ transitions of hydrogen and helium isotopes. The intense LEAR beam, stopped in the cyclotron trap at low gas pressure, provides a unique~X-ray~source with sufficient brightness. Charge coupled devices with their excellent background rejection and energy resolution allow a precise determination of the strong shifts and widths of the 1s hyperfine states of protonium, in addition the detection of the $\\bar{p}$D K$\\alpha$ transition should be possible. A focussing crystal spectrometer with a resolution $\\Delta$E/E of about l0$ ^- ^{4} $, which is superior in the accuracy of the energy determination by two orders of magnitude as compared to the present detection methods, will be used to measure the energies of the L$\\alpha$ transitions. This permits a first direct measure...

The United States Atomic Energy Commission programme on isotopes and radiation development and its industrial impact

Energy Technology Data Exchange (ETDEWEB)

Fowler, E E [United States Atomic Energy Commission, Division of Isotopes Development, Washington, DC (United States)

1965-02-01

The US Atomic Energy Commission isotopes development programme is directed towards (a) encouraging development of beneficial applications of radioisotopes and radiation technology, particularly those designed to meet problems of urgent public interest; (b) accelerating the potential contribution of radioisotopes and radiation applications to the national economy and welfare, and (c) contributing to world development in the peaceful uses of atomic energy. The programme is administered by the Division of Isotopes Development. The programme objectives are being achieved through a multiphase research and development programme including the following major elements: (1) Radiation pasteurization of food, involving development of technology for low dose radiation processing of representative fruit and fishery products to extend their refrigerated shelf life; (2) Process radiation development, directed to fostering development of a broad technology leading to productive use of mega curie quantities of fission products and other radioisotopes for process radiation purposes; (3) Radioisotope technology development, directed to creating a broad base of new and improved technology required for extending and speeding up the application of radioisotopes in science and technology; (4) Radioisotope production and separation technology, directed to insuring availability of radioisotopes to meet the changing needs of advancing science and technology in the USA; (5) Isotopic power and heat sources development, aimed at the development and production of isotopic fuels and fuel forms for a broad spectrum of thermal applications, including SNAP auxiliary electrical power devices; (6) Analysis and applications, whose objective is to identify and analyse radioisotope and radiation research and development activities in the United States of America and abroad; to establish channels of communication with science, government, and industry, and to encourage broad dissemination and productive

Reduction of chemical formulas from the isotopic peak distributions of high-resolution mass spectra.

Science.gov (United States)

Roussis, Stilianos G; Proulx, Richard

2003-03-15

A method has been developed for the reduction of the chemical formulas of compounds in complex mixtures from the isotopic peak distributions of high-resolution mass spectra. The method is based on the principle that the observed isotopic peak distribution of a mixture of compounds is a linear combination of the isotopic peak distributions of the individual compounds in the mixture. All possible chemical formulas that meet specific criteria (e.g., type and number of atoms in structure, limits of unsaturation, etc.) are enumerated, and theoretical isotopic peak distributions are generated for each formula. The relative amount of each formula is obtained from the accurately measured isotopic peak distribution and the calculated isotopic peak distributions of all candidate formulas. The formulas of compounds in simple spectra, where peak components are fully resolved, are rapidly determined by direct comparison of the calculated and experimental isotopic peak distributions. The singular value decomposition linear algebra method is used to determine the contributions of compounds in complex spectra containing unresolved peak components. The principles of the approach and typical application examples are presented. The method is most useful for the characterization of complex spectra containing partially resolved peaks and structures with multiisotopic elements.

Production and separation of neutron-rich rare isotopes around and below the Fermi energy

CERN Document Server

Souliotis, G A; Chubarian, G; Yennello, S J

2003-01-01

The production of n-rich rare isotopes around and below the Fermi energy is investigated using beams from the K500 Superconducting Cyclotron and the MARS recoil separator at the Cyclotron Institute of Texas A and M University. The experimental results from the reactions of 25 MeV/nucleon sup 8 sup 6 Kr + sup 6 sup 4 Ni and 21 MeV/nucleon sup 1 sup 2 sup 4 Sn + sup 1 sup 2 sup 4 Sn are presented and compared with simulations. The calculations involve a deep inelastic transfer (DIT) code for the primary interaction stage followed by the code GEMINI for the de-excitation stage. The results are also compared with the EPAX parametrization. The data on the 25 MeV/nucleon sup 8 sup 6 Kr + sup 6 sup 4 Ni reaction show that both proton-removal and several-neutron pick-up isotopes are produced. An enhancement is observed in the production of n-rich isotopes close to the projectile relative to the predictions of DIT/GEMINI and the expectations of EPAX. The data of 21 MeV/nucleon sup 1 sup 2 sup 4 Sn + sup 1 sup 2 sup 4 ...

Status of High Flux Isotope Reactor (HFIR) post-restart safety analysis and documentation upgrades

International Nuclear Information System (INIS)

Cook, D.H.; Radcliff, T.D.; Rothrock, R.B.; Schreiber, R.E.

1990-01-01

The High Flux Isotope Reactor (HFIR), an experimental reactor located at the Oak Ridge National Laboratory (ORNL) and operated for the US Department of Energy by Martin Marietta Energy Systems, was shut down in November, 1986 after the discovery of unexpected neutron embrittlement of the reactor vessel. The reactor was restarted in April, 1989, following an extensive review by DOE and ORNL of the HFIR design, safety, operation, maintenance and management, and the implementation of several upgrades to HFIR safety-related hardware, analyses, documents and procedures. This included establishing new operating conditions to provide added margin against pressure vessel failure, as well as the addition, or upgrading, of specific safety-related hardware. This paper summarizes the status of some of the follow-on (post-restart) activities which are currently in progress, and which will result in a comprehensive set of safety analyses and documentation for the HFIR, comparable with current practice in commercial nuclear power plants. 8 refs

Determination of the theoretical feasibility for the transmutation of europium isotopes from high flux isotope reactor control cylinders

International Nuclear Information System (INIS)

Elam, K.R.; Reich, W.J.

1995-09-01

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) is a 100 MWth light-water research reactor designed and built in the 1960s primarily for the production of transuranic isotopes. The HFIR is equipped with two concentric cylindrical blade assemblies, known as control cylinders, that are used to control reactor power. These control cylinders, which become highly radioactive from neutron exposure, are periodically replaced as part of the normal operation of the reactor. The highly radioactive region of the control cylinders is composed of europium oxide in an aluminum matrix. The spent HFIR control cylinders have historically been emplaced in the ORNL Waste Area Grouping (WAG) 6. The control cylinders pose a potential radiological hazard due to the long lived radiotoxic europium isotopes 152 Eu, 154 Eu, and 155 Eu. In a 1991 health evaluation of WAG 6 (ERD 1991) it was shown that these cylinders were a major component of the total radioactivity in WAG 6 and posed a potential exposure hazard to the public in some of the postulated assessment scenarios. These health evaluations, though preliminary and conservative in nature, illustrate the incentive to investigate methods for permanent destruction of the europium radionuclides. When the cost of removing the control cylinders from WAG 6, performing chemical separations and irradiating the material in HFIR are factored in, the option of leaving the control cylinders in place for decay must be considered. Other options, such as construction of an engineered barrier around the disposal silos to reduce the chance of migration, should also be analyzed

Boron isotopic enrichment by displacement chromatography

International Nuclear Information System (INIS)

Mohapatra, K.K.; Bose, Arun

2014-01-01

10 B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10 B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH) 4 - ) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10 B and 11 B

Tritium conductivity and isotope effect in proton-conducting perovskites

International Nuclear Information System (INIS)

Mukundan, R.; Brosha, E.L.; Birdsell, S.A.; Costello, A.L.; Garzon, F.H.; Willms, R.S.

1999-01-01

The tritium ion conductivities of SrZr 0.9 Yb 0.1 O 2.95 and BaCe 0.9 Yb 0.1 O 2.95 have been measured by ac impedance analysis. The high tritium conductivity of these perovskites could potentially lead to their application as an electrochemical membrane for the recovery of tritium from tritiated gas streams. The conductivities of these perovskites, along with SrCe 0.95 Yb 0.05 O 2.975 , were also measured in hydrogen- and deuterium-containing atmospheres to illustrate the isotope effect. For the strontium zirconate and barium cerate samples, the impedance plot consists of two clearly resolved arcs, a bulk and a grain boundary arc, in the temperature range 50--350 C. However, for the strontium cerate sample, the clear resolution of the bulk conductivity was not possible and only the total conductivity was measurable. Thus, the isotope effect was clearly established only for the strontium zirconate and barium cerate samples. The decrease in bulk conductivity with increasing isotope mass was found to be a result of an increase in the activation energy for conduction accompanied by a decrease in the pre-exponential factor. Since the concentration of the mobile species (H+, D+, or T+) should remain relatively constant at T < 350 C, this increase in activation energy is directly attributable to the increased activation energy for the isotope mobility

Seismic, high wind, tornado, and probabilistic risk assessment of the high flux isotope reactor

International Nuclear Information System (INIS)

Harris, S.P.; Hashimoto, P.S.; Dizon, J.O.; Hashimoto, P.S.

1989-01-01

Natural phenomena analyses were performed on the High Flux Isotope Reactor (HFIR). Deterministic and probabilistic evaluations were made to determine the risks resulting from earthquakes, high winds, and tornadoes. Analytic methods in conjunction with field evaluations and an earthquake experience data base evaluation methods were used to provide more realistic results in a shorter amount of time. Plant modifications completed in preparation for HFIR restart and potential future enhancements are discussed

Data mining for isotope discrimination in atom probe tomography

Energy Technology Data Exchange (ETDEWEB)

Broderick, Scott R. [Department of Materials Science and Engineering and Institute for Combinatorial Discovery, Iowa State University, Ames, IA 50011-2230 (United States); Bryden, Aaron [Ames National Laboratory, Ames, IA 50011-2230 (United States); Suram, Santosh K. [Department of Materials Science and Engineering and Institute for Combinatorial Discovery, Iowa State University, Ames, IA 50011-2230 (United States); Rajan, Krishna, E-mail: krajan@iastate.edu [Department of Materials Science and Engineering and Institute for Combinatorial Discovery, Iowa State University, Ames, IA 50011-2230 (United States)

2013-09-15

Ions with similar time-of-flights (TOF) can be discriminated by mapping their kinetic energy. While current generation position-sensitive detectors have been considered insufficient for capturing the isotope kinetic energy, we demonstrate in this paper that statistical learning methodologies can be used to capture the kinetic energy from all of the parameters currently measured by mathematically transforming the signal. This approach works because the kinetic energy is sufficiently described by the descriptors on the potential, the material, and the evaporation process within atom probe tomography (APT). We discriminate the isotopes for Mg and Al by capturing the kinetic energy, and then decompose the TOF spectrum into its isotope components and identify the isotope for each individual atom measured. This work demonstrates the value of advanced data mining methods to help enhance the information resolution of the atom probe. - Highlights: ► Atom probe tomography and statistical learning were combined for data enhancement. ► Multiple eigenvalue decompositions decomposed a spectrum with overlapping peaks. ► The isotope of each atom was determined by kinetic energy discrimination. ► Eigenspectra were identified and new chemical information was identified.

Isotopic dependence of GCR fluence behind shielding

International Nuclear Information System (INIS)

Cucinotta, Francis A.; Wilson, John W.; Saganti, Premkumar; Hu, Xiaodong; Kim, Myung-Hee Y.; Cleghorn, Timothy; Zeitlin, Cary; Tripathi, Ram K.

2006-01-01

In this paper we consider the effects of the isotopic composition of the primary galactic cosmic rays (GCR), nuclear fragmentation cross sections, and isotopic-grid on the solution to transport models used for shielding studies. Satellite measurements are used to describe the isotopic composition of the GCR. For the nuclear interaction data-base and transport solution, we use the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) and high-charge and energy (HZETRN) transport code, respectively. The QMSFRG model is shown to accurately describe existing fragmentation data including proper description of the odd-even effects as function of the iso-spin dependence on the projectile nucleus. The principle finding of this study is that large errors (±100%) will occur in the mass-fluence spectra when comparing transport models that use a complete isotopic-grid (∼170 ions) to ones that use a reduced isotopic-grid, for example the 59 ion-grid used in the HZETRN code in the past; however, less significant errors (<+/-20%) occur in the elemental-fluence spectra. Because a complete isotopic-grid is readily handled on small computer workstations and is needed for several applications studying GCR propagation and scattering, it is recommended that they be used for future GCR studies

Influence of water on clumped-isotope bond reordering kinetics in calcite

Science.gov (United States)

Brenner, Dana C.; Passey, Benjamin H.; Stolper, Daniel A.

2018-03-01

Oxygen self-diffusion in calcite and many other minerals is considerably faster under wet conditions relative to dry conditions. Here we investigate whether this "water effect" also holds true for solid-state isotope exchange reactions that alter the abundance of carbonate groups with multiple rare isotopes ('clumped' isotope groups) via the process of solid-state bond reordering. We present clumped-isotope reordering rates for optical calcite heated under wet, high-pressure (100 MPa) conditions. We observe only modest increases in reordering rates under such conditions compared with rates for the same material reacted in dry CO2 under low-pressure conditions. Activation energies under wet, high-pressure conditions are indistinguishable from those for dry, low-pressure conditions, while rate constants are resolvably higher (up to ∼3 times) for wet, high-pressure relative to dry, low-pressure conditions in most of our interpretations of experimental results. This contrasts with the water effect for oxygen self-diffusion in calcite, which is associated with lower activation energies, and diffusion coefficients that are ≥103 times higher compared with dry (pure CO2) conditions in the temperature range of this study (385-450 °C). The water effect for clumped-isotopes leads to calculated apparent equilibrium temperatures ("blocking temperatures") for typical geological cooling rates that are only a few degrees higher than those for dry conditions, while O self-diffusion blocking temperatures in calcite grains are ∼150-200 °C lower in wet conditions compared with dry conditions. Since clumped-isotope reordering is a distributed process that occurs throughout the mineral volume, our clumped-isotope results support the suggestion of Labotka et al. (2011) that the water effect in calcite does not involve major changes in bulk (volume) diffusivity, but rather is primarily a surface phenomenon that facilitates oxygen exchange between the calcite surface and external

Delayed Particle Study of Neutron Rich Lithium Isotopes

CERN Multimedia

Marechal, F; Perrot, F

2002-01-01

We propose to make a systematic complete coincidence study of $\\beta$-delayed particles from the decay of neutron-rich lithium isotopes. The lithium isotopes with A=9,10,11 have proven to contain a vast information on nuclear structure and especially on the formation of halo nuclei. A mapping of the $\\beta$-strength at high energies in the daughter nucleus will make possible a detailed test of our understanding of their structure. An essential step is the comparison of $\\beta$-strength patterns in $^{11}$Li and the core nucleus $^{9}$Li, another is the full characterization of the break-up processes following the $\\beta$-decay. To enable such a measurement of the full decay process we will use a highly segmented detection system where energy and emission angles of both charged and neutral particles are detected in coincidence and with high efficiency and accuracy. We ask for a total of 30 shifts (21 shifts for $^{11}$Li, 9 shifts $^{9}$Li adding 5 shifts for setting up with stable beam) using a Ta-foil target...

Determination of Pu isotopic composition and 241Am by high resolution gamma spectrometry on solid samples

International Nuclear Information System (INIS)

Sarkar, Arnab; Paul, Sumana; Aggarwal, Suresh K.; Tomar, Bhupendra S.

2011-08-01

The present report gives a detailed account of the development of non-destructive assay technique using high resolution gamma-ray spectrometry (HRGS) for determination of plutonium (Pu) isotopic composition and the 241 Am content in solid Pu samples. Energy range 120-420 keV was used in this study. The methodology involves in situ relative efficiency calibration during the measurement process itself, to reduce the errors and increase the reliability of the method. Twenty solid Pu samples of power reactor and research reactor grade were analyzed by this method and the results were compared with those obtained by thermal ionization mass spectrometry. The accuracy of the final results depends strongly upon the accuracy of the available nuclear data (decay constant, gamma abundance etc.). MATLAB based programme was written to perform the analysis. A counting time of 4 hour was chosen for achieving good statistics on the results for samples having 100-200 mg of Pu. The attainable accuracy is found to be 0.5-1% for the fissile isotopes ( 239 Pu + 241 Pu) and 5-10% for 241 Am content. (author)

Development of the high temperature ion-source for the Grenoble electromagnetic isotope separator

International Nuclear Information System (INIS)

Bouriant, M.

1968-01-01

The production of high purity stable or radioactive isotopes (≥ 99.99 per cent) using electromagnetic separation require for equipment having a high resolving power. Besides, and in order to collect rare or short half-life isotopes, the efficiency of the ion-source must be high (η > 5 to 10 per cent). With this in view, the source built operates at high temperatures (2500-3000 C) and makes use of ionisation by electronic bombardment or of thermo-ionisation. A summary is given in the first part of this work on the essential characteristics of the isotope separator ion Sources; a diagram of the principle of the source built is then given together with its characteristics. In the second part are given the values of the resolving power and of the efficiency of the Grenoble isotope separator fitted with such a source. The resolving power measured at 10 per cent of the peak height is of the order of 200. At the first magnetic stage the efficiency is between 1 and 26 per cent for a range of elements evaporating between 200 and 3000 C. Thus equipped, the separator has for example given, at the first stage, 10 mg of 180 Hf at (99.69 ± 0.1) per cent corresponding to an enrichment coefficient of 580; recently 2 mg of 150 Nd at (99.996 ± 0.002) per cent corresponding to an enrichment coefficient of 4.2 x 10 5 has been obtained at the second stage. (author) [fr

BSATOM - package of programs for calculating the energy levels and wave functions of helium-like systems taking into account isotope effects

International Nuclear Information System (INIS)

Abrashkevich, A.G.; Abrashkevich, D.G.; Vinitskij, S.I.; Puzynin, I.V.

1989-01-01

Description of package BCATOM for calculating the energy levels and wave functions of helium-like systems in the hyperspherical adiabatic approach taking into account the isotopic effects is given. The corresponding Sturm-Liouville problems are approximated by the difference method and the high order accuracy finite element method. The obtained generalized algebraic eigenvalue problems are solved by subspace iteration method. Possibilities of the package are demonstrated by calculating the ground state characteristics of a negative hydrogen ion. 33 refs.; 1 fig

AMODS and High Energy Density Sciences

International Nuclear Information System (INIS)

Rhee, Y.-J.

2011-01-01

Following a brief introduction to the Lab for Quantum Optics (LFQO) in KAERI, which has been devoted to the research on atomic spectroscopy for more than 20 years with precision measurement of atomic parameters such as isotope shift, hyperfine structures, autoionization levels and so on as well as with theoretical analysis of atomic systems by developing relativistic calculation methodologies for laser propagation and population dynamics, electron impact ionization, radiative transitions of high Z materials, etc for the application to isotope separation, the AMODS (Atomic Molecular and Optical Database Systems) which was established in 1997 and has been a member of International Data Center Network of IAEA since then is explained by giving an information on the data sources and internal structure of the compilation of AMODS. Since AMODS was explained in detail during last DCN meeting, just a brief introduction is given this time. Then more specific research themes carried out in LFQO in conjunction with A+M data are discussed, including (1) electron impact ionization processes of W, Mo, Be, C, etc, (2) spectra of highly charged ions of W, Xe, and Si, (3) dielectronic recombination process of Fe ion. Also given are the talk about research activities about the simulations of high energy density experiments such as those performed at (1) GEKKO laser facility (Japan) for X-ray photoionization of low temperature Si plasma, which can explain the unsolved arguments on the X-ray spectra of black holes and/or neutron stars, (2) VULCAN laser facility (UK) for two dimensional compression of cylindrical target and investigation of hot electron transport in the compressed target plasma to understand the fast ignition process of laser fusion, (3) LULI laser facility (France) and TITAN laser facility (USA) for one dimensional compression of aluminum targets with different laser energies, and (4) PALS facility (Czech Republic) for 'Laser Induced Cavity Pressure Acceleration' to

Application of helium isotopes in shallow groundwaters for geothermal energy exploration in the Upper Rhine Graben

International Nuclear Information System (INIS)

Freundt, Florian

2017-01-01

The helium isotope system is an established tool in hydrology for identifying mantle fluids in deep aquifers. This study applies the helium tracer system for the first time in shallow, unconfined aquifers of the Upper Rhine Graben. The Graben is a part of the Cenozoic Rift system of Western and Central Europe, a continental rift zone with unusually high geothermal gradients, making it an ideal region of Germany for geothermal energy development. The aim of this study is to develop a suite of natural groundwater tracers able to achieve a cost and effort reduction in geothermal prospection. The 3 He/ 4 He-ratio is therefore applied, as part of a multi-tracer approach including 3 H, δ 18 O, δ 2 H, δ 13 C, 14 C and 222 Rn, to identify and locate fault zones with suitable permeabilities for power plant operation. Three target areas along the graben were studied, each located on one of the main fault lines. A mantle-derived helium signature could be identified and separated from tritiogenic helium in a shallow aquifer in the north-west of the Graben. The mixing component of mantle-derived fluid in the shallow groundwater is calculated to reach up to 5%, based on the analysis of the 3 He/ 4 He isotope system. The employed method proves that the local permeability of the fault zone is high. The origin of the locally occurring upwelling of salinated water can be redetermined by the data.

The Gd-isotopic fuel for high burnup in PWR's

Energy Technology Data Exchange (ETDEWEB)

Dias, Marcio Soares; Mattos, João Roberto L. de; Andrade, Edison Pereira de, E-mail: marciod@cdtn.br, E-mail: jrmattos@cdtn.br, E-mail: epa@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Today, the discussion about the high burnup fuel is beyond the current fuel enrichment licensing and burnup limits. Licensing issues and material/design developments are again key features in further development of the LWR fuel design. Nevertheless, technological and economical solutions are already available or will be available in a short time. In order to prevent the growth of the technological gap, Brazil's nuclear sector needs to invest in the training of new human resources, in the access to international databases, and in the upgrading existing infrastructure. Experimental database and R&D infrastructure are essential components to support the autonomous development of Brazilian Nuclear Reactors, promoting the development of national technologies. The (U,Gd)O{sub 2} isotopic fuel proposed by the CDTN's staff solve two main issues in the high burnup fuel, which are (1) the peak of reactivity resulting from the Gd-157 fast burnup, and (2) the peak of temperature in the (U,Gd)O{sub 2} nuclear fuel resulting from detrimental effects in the thermal properties for gadolinia additions higher than 2%. A sustainable future can be envisaged for the nuclear energy. (author)

Fission fragment mass and total kinetic energy distributions of spontaneously fissioning plutonium isotopes

Science.gov (United States)

Pomorski, K.; Nerlo-Pomorska, B.; Bartel, J.; Schmitt, C.

2018-03-01

The fission-fragment mass and total kinetic energy (TKE) distributions are evaluated in a quantum mechanical framework using elongation, mass asymmetry, neck degree of freedom as the relevant collective parameters in the Fourier shape parametrization recently developed by us. The potential energy surfaces (PES) are calculated within the macroscopic-microscopic model based on the Lublin-Strasbourg Drop (LSD), the Yukawa-folded (YF) single-particle potential and a monopole pairing force. The PES are presented and analysed in detail for even-even Plutonium isotopes with A = 236-246. They reveal deep asymmetric valleys. The fission-fragment mass and TKE distributions are obtained from the ground state of a collective Hamiltonian computed within the Born-Oppenheimer approximation, in the WKB approach by introducing a neck-dependent fission probability. The calculated mass and total kinetic energy distributions are found in good agreement with the data.

Inverse kinematics technique for the study of fission-fragment isotopic yields at GANIL energies

International Nuclear Information System (INIS)

Delaune, O.

2012-01-01

The characteristics of the fission-products distributions result of dynamical and quantum properties of the deformation process of the fissioning nucleus. These distributions have also an interest for the conception of new nuclear power plants or for the transmutation of the nuclear wastes. Up to now, our understanding of the nuclear fission remains restricted because of experimental limitations. In particular, yields of the heavy fission products are difficult to get with precision. In this work, an innovative experimental technique is presented. It is based on the use of inverse kinematics coupled to the use of a spectrometer, in which a 238 U beam at 6 or 24 A MeV impinges on light targets. Several actinides, from 238 U to 250 Cf, are produced by transfer or fusion reactions, with an excitation energy ranges from ten to few hundreds MeV depending on the reaction and the beam energy. The fission fragments of these actinides are detected by the VAMOS spectrometer or the LISE separator. The isotopic yields of fission products are completely measured for different fissioning systems. The neutron excess of the fragments is used to characterise the isotopic distributions. Its evolution with excitation energy gives important insights on the mechanisms of the compound-nucleus formation and its deexcitation. Neutron excess is also used to determine the multiplicity of neutrons evaporated by the fragments. The role of the proton and neutron shell effects into the formation of fission fragments is also discussed. (author) [fr

Seismic, high wind, tornado, and probabilistic risk assessments of the High Flux Isotope Reactor

International Nuclear Information System (INIS)

Harris, S.P.; Stover, R.L.; Hashimoto, P.S.; Dizon, J.O.

1989-01-01

Natural phenomena analyses were performed on the High Flux Isotope Reactor (HFIR) Deterministic and probabilistic evaluations were made to determine the risks resulting from earthquakes, high winds, and tornadoes. Analytic methods in conjunction with field evaluations and an earthquake experience data base evaluation methods were used to provide more realistic results in a shorter amount of time. Plant modifications completed in preparation for HFIR restart and potential future enhancements are discussed. 5 figs

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

Upper Campanian–Maastrichtian nannofossil biostratigraphy and high-resolution carbon-isotope stratigraphy of the Danish Basin

DEFF Research Database (Denmark)

Thibault, Nicolas Rudolph; Harlou, Rikke; Schovsbo, Niels

2012-01-01

High-resolution carbon isotope stratigraphy of the upper Campanian – Maastrichtian is recorded in the Boreal Realm from a total of 1968 bulk chalk samples of the Stevns-1 core, eastern Denmark. Isotopic trends are calibrated by calcareous nannofossil bio-events and are correlated with a lower...

Measurement of crosstalk contamination in dual isotope imaging by means of energy spectra and images

International Nuclear Information System (INIS)

Kojima, Akihiro; Tsuji, Akinori; Ohyama, Yoichi; Nabeshima, Mitsuko; Kira, Tomohiro; Nakashima, Rumi; Tomiguchi, Seiji; Takahashi, Mutsumasa; Matsumoto, Masanori.

1994-01-01

The purpose of this study was to estimate the value of crosstalk contamination ratio (CTR) by analyzing energy spectra and scintigraphic images using a phantom and three radionuclides of 201 Tl, 99m Tc and 123 I. A 2 cm x 2 cm plate source filled with single radionuclide was placed in a water tank and its depth changed from 0 cm to 10 cm. Energy spectra and planar images were obtained using a gamma camera with either a low-energy (150 keV) or a medium-energy (200 keV) collimator. The value of CTR was calculated for two combinations : 1) 201 Tl and 99m Tc and 2) 201 Tl and 123 I. The energy window width at a photopeak was 20% for each radionuclide. The data were analyzed in two regions: a region where primary photons were mainly included in (region 1, 2 cm x 2 cm) and a region where both primary and scattered photons were included in (region 2, 10 cm x 10 cm). The results from analyses of the images showed that the CTR of Tl/Tc and Tl/I (0.064-0.101) were almost equal to those of Tc/Tl and I/Tl (0.056-0.148) for the region 1, but the CTR of Tl/Tc and Tl/I (0.212-0.381) were 2 times greater than those of Tc/Tl and I/Tl (0.092-0.172) for the region 2. Furthermore, these results showed good agreement between the CTR by energy spectra and those by images. For imaging with 123 I the medium-energy collimator had less blur than the low-energy collimator, in particular for the smaller source-to-collimator distance. In conclusion, the crosstalk contamination in dual-isotope study affects quantification of two radionuclides' activities. Our results are useful to evaluate images acquired using the dual-isotope technique and develop a new correction method for such crosstalk contamination by analyzing the energy spectra and images obtained. (author)

Isotope Identification

Energy Technology Data Exchange (ETDEWEB)

Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-18

The objective of this training modules is to examine the process of using gamma spectroscopy for radionuclide identification; apply pattern recognition to gamma spectra; identify methods of verifying energy calibration; and discuss potential causes of isotope misidentification.

Production of platinum radioisotopes at Brookhaven Linac Isotope Producer (BLIP

Directory of Open Access Journals (Sweden)

Smith Suzanne V.

2017-01-01

Full Text Available The accelerator production of platinum isotopes was investigated at the Brookhaven Linac Isotope Producer (BLIP. In this study high purity natural platinum foils were irradiated at 53.2, 65.7, 105.2, 151.9, 162.9 and 173.3.MeV. The irradiated foils were digested in aqua regia and then converted to their hydrochloride salt with concentrated hydrochloric acid before analyzing by gamma spectrometry periodically for at least 10 days post end of bombardment. A wide range of platinum (Pt, gold (Au and iridium (Ir isotopes were identified. Effective cross sections at BLIP for Pt-188, Pt-189, Pt-191 and Pt-195m were compared to literature and theoretical cross sections determined using Empire-3.2. The majority of the effective cross sections (<70 MeV confirm those reported in the literature. While the absolute values of the theoretical cross sections were up to a factor of 3 lower, Empire 3.2 modeled thresholds and maxima correlated well with experimental values. Preliminary evaluation into a rapid separation of Pt isotopes from high levels of Ir and Au isotopes proved to be a promising approach for large scale production. In conclusion, this study demonstrated that with the use of isotopically enriched target material accelerator production of selected platinum isotopes is feasible over a wide proton energy range.

Determination of 239Pu/240Pu isotopic ratio by high resolution alpha-particle spectrometry

International Nuclear Information System (INIS)

Amoudry, F.; Burger, P.

1983-05-01

The development of passivated ion-implanted silicon detectors and of very thin alpha-particle sources improves the resolution of alpha-particle spectra and allows to separate energy pics up to now unseparate. The 239 Pu/ 240 Pu isotopic ratio of a mixture has been measured using the alpha spectrometry deconvolution code DEMO [fr

LSDS Development for Isotopic Fissile Assay in Spent Fuel

Energy Technology Data Exchange (ETDEWEB)

Lee, Yong Deok; Park, Chang Je; Park, Geun Il; Lee, Jung Won; Song, Kee Chan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2011-07-01

As an option to reduce a spent fuel and reuse an existing fissile material in spent fuel, sodium fast reactor SFR program linked with pyro-processing is under development in KAERI. A uranium-TRU mixture through a pyro-process is used to fabricate SFR fuel. An assay of isotopic fissile content plays an important role in an optimum design of storage site and reuse of fissile materials of spent fuel. Lead slowing down spectrometer LSDS is being developed in KAERI to analyze isotopic fissile material content. LSDS has several features: direct fissile assay, near real time fissile assay, no influence from radiation background, fissile isotopic assay and applicable to spent fuel and recycled fuel. Based on the designed geometry, neutron energy resolution was investigated. The neutron energy spectrum was analyzed as well. Spent fuel emits large number of neutrons by spontaneous fission. Neutron generator must overcome the neutron background to get the pure fission signals from fissile materials. Neutron generator is planned to have compact system with one section electron linac which is easy maintenance, less cost and high neutron yield. The LSD has the power to resolve the fission characteristics from each fissile material. This feature can analyze the content of isotopic fissile. From 1keV to 0.1eV energy range, the energy resolution is enough to get the individual fissile fission signatures. The dominant fission signature is shown below 1eV for each fissile isotope. The neutron generation system with target was designed to get fission signals by fissile materials. The system was decided to overcome neutron backgrounds and to get good counting statistics. Finally, an accurate fissile material content will contribute to safety of spent fuel reuse in future nuclear energy system and optimum design of spent fuel storage site. Additionally, an accurate fissile material content will increase international transparence and credibility for the reuse of PWR spent fuel.

LSDS Development for Isotopic Fissile Assay in Spent Fuel

International Nuclear Information System (INIS)

Lee, Yong Deok; Park, Chang Je; Park, Geun Il; Lee, Jung Won; Song, Kee Chan

2011-01-01

As an option to reduce a spent fuel and reuse an existing fissile material in spent fuel, sodium fast reactor SFR program linked with pyro-processing is under development in KAERI. A uranium-TRU mixture through a pyro-process is used to fabricate SFR fuel. An assay of isotopic fissile content plays an important role in an optimum design of storage site and reuse of fissile materials of spent fuel. Lead slowing down spectrometer LSDS is being developed in KAERI to analyze isotopic fissile material content. LSDS has several features: direct fissile assay, near real time fissile assay, no influence from radiation background, fissile isotopic assay and applicable to spent fuel and recycled fuel. Based on the designed geometry, neutron energy resolution was investigated. The neutron energy spectrum was analyzed as well. Spent fuel emits large number of neutrons by spontaneous fission. Neutron generator must overcome the neutron background to get the pure fission signals from fissile materials. Neutron generator is planned to have compact system with one section electron linac which is easy maintenance, less cost and high neutron yield. The LSD has the power to resolve the fission characteristics from each fissile material. This feature can analyze the content of isotopic fissile. From 1keV to 0.1eV energy range, the energy resolution is enough to get the individual fissile fission signatures. The dominant fission signature is shown below 1eV for each fissile isotope. The neutron generation system with target was designed to get fission signals by fissile materials. The system was decided to overcome neutron backgrounds and to get good counting statistics. Finally, an accurate fissile material content will contribute to safety of spent fuel reuse in future nuclear energy system and optimum design of spent fuel storage site. Additionally, an accurate fissile material content will increase international transparence and credibility for the reuse of PWR spent fuel

Nuclear interactions of high energy heavy ions and applications in astrophysics

International Nuclear Information System (INIS)

Wefel, J.P.

1992-01-01

This program was established for the purpose of studying projectile fragmentation; (1) as a function of energy, focusing first on the intermediate energy region, < 1 GeV/nucleon, where there have been few previous measurements and no systematic studies, and (2) as a function of projectile mass, starting with light beams and proceeding to species as heavy as nickel (and possibly beyond). The intermediate energy region is important as the transition between the lower energy data, where the interaction appears to be dominated by collective effects and the decay of excited nuclei, and the highest energy results, where nucleon-nucleon interactions are fundamental, ''limiting fragmentation'' applies, and the nucleus may well break-up before any de-excitation. The mass dependence of projectile fragmentation is largely unknown since most detailed work has involved light ion beams. Nuclear structure effects, for example, may well be quite prominent for heavier beams. Furthermore, the nuclear excitation functions for the production of different fragment isotopes have immediate application to the astrophysical interpretation of existing isotopic datasets obtained from balloon and satellite measurements of galactic cosmic rays

Model-based crosstalk compensation in simultaneous dual isotope SPECT

International Nuclear Information System (INIS)

Frey, E.C.; Tsui, B.M.W.; Du, A.Y.; Song, X.Y.

2002-01-01

Simultaneous dual isotope imaging has the potential of allowing imaging of two different physiological processes at the same time. Two examples are Tc-99m stress and Tl-201 rest myocardial perfusion imaging and Tc-99m perfusion and I-123 neuroreceptor brain imaging. However, for both of these cases crosstalk is a significant problem that results in degradation of the simultaneously acquired images. For the Tc-99m and Tl-201 case, the crosstalk includes downscatter and the generation of Pb x-rays detected in the Tl-201 energy window. For the Tc-99m/I-123 case, the crosstalk includes overlap of the two photopeaks, downscatter, especially of the 159 keV photons into the Tc-99m energy window, and contamination of the images of both isotopes by low abundance, high-energy I-123 photons. We have developed methods to accurately model the crosstalk in both cases. For the Tc-99m/Tl-201 case, the crosstalk model uses a previously described method for modeling scatter, effective source scatter estimation (ESSE). The scatter estimates are combined with a parameterization of the Pb x-ray response of the collimator to estimate the crosstalk. For the I-123/Tc-99m case we combine ESSE with a MC simulated collimator scatter and penetration responses to model the contamination due to the high-energy photons from I-123. In both cases the crosstalk models have been incorporated into an iterative reconstruction procedure that allows simultaneous reconstruction of the activity distributions from two isotopes including crosstalk compensation We have evaluated these methods both by Monte Carlo simulation studies and using physical phantom experiments. We find that the methods perform well and produce images with a quality and contrast approaching that of separately acquired images. However, the compensated simultaneously acquired images do have an increase in image noise. To reduce the noise we have applied ideal observer methodology to determine optimal energy windows and relative

The South African isotope facility project

Science.gov (United States)

Bark, R. A.; Barnard, A. H.; Conradie, J. L.; de Villiers, J. G.; van Schalkwyk, P. A.

2018-05-01

The South African Isotope Facility (SAIF) is a project in which iThemba LABS plans to build a radioactive-ion beam (RIB) facility. The project is divided into the Accelerator Centre of Exotic Isotopes (ACE Isotopes) and the Accelerator Centre for Exotic Beams (ACE Beams). For ACE Isotopes, a high-current, 70 MeV cyclotron will be acquired to take radionuclide production off the existing Separated Sector Cyclotron (SSC). A freed up SSC will then be available for an increased tempo of nuclear physics research and to serve as a driver accelerator for the ACE Beams project, in which protons will be used for the direct fission of Uranium, producing beams of fission fragments. The ACE Beams project has begun with "LeRIB" - a Low Energy RIB facility, now under construction. In a collaboration with INFN Legnaro, the target/ion-source "front-end" will be a copy of the front-end developed for the SPES project. A variety of targets may be inserted into the SPES front-end; a uranium-carbide target has been designed to produce up to 2 × 1013 fission/s using a 70 MeV proton beam of 150 µA intensity.

Production of Medical isotope Technecium-99 from DT Fusion neutrons

Science.gov (United States)

Boguski, John; Gentile, Charles; Ascione, George

2011-10-01

High energy neutrons produced in DT fusion reactors have a secondary application for use in the synthesis of valuable man-made isotopes utilized in industry today. One such isotope is metastable Technecium-99 (Tc99m), a low energy gamma emitter used in ~ 85% of all medical imaging diagnostics. Tc99m is created through beta decay of Molybdenum-99 (Mo99), which itself has only a 66 hour half-life and must be created from a neutron capture by the widely available and stable isotope Molydenum-98. Current worldwide production of Tc99m occurs in just five locations and relies on obtaining the fission byproduct Mo99 from highly enriched Uranium reactors. A Tc99m generator using DT fusion neutrons, however, could potentially be operated at individual hospitals and medical facilities without the use of any fissile material. The neutron interaction of the DT neutrons with Molybdenum in a potential device geometry was modeled using Monte Carlo neutron transport code MCNP. Trial experiments were also performed to test the viability of using DT neutrons to create ample quantities of Tc99m. Modeling and test results will follow.

MEASUREMENTS OF COSMIC-RAY HYDROGEN AND HELIUM ISOTOPES WITH THE PAMELA EXPERIMENT

International Nuclear Information System (INIS)

Adriani, O.; Bongi, M.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Bruno, A.; Boezio, M.; Bonvicini, V.; Formato, V.; Bogomolov, E. A.; Bottai, S.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Santis, C. De; Castellini, G.; Donato, C. De; Simone, N. De; Felice, V. Di

2016-01-01

The cosmic-ray hydrogen and helium ( 1 H, 2 H, 3 He, 4 He) isotopic composition has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on board the Resurs-DK1 satellite on 2006 June 15. The rare isotopes 2 H and 3 He in cosmic rays are believed to originate mainly from the interaction of high-energy protons and helium with the galactic interstellar medium. The isotopic composition was measured between 100 and 1100 MeV/n for hydrogen and between 100 and 1400 MeV/n for helium isotopes using two different detector systems over the 23rd solar minimum from 2006 July to 2007 December

Generalized-seniority scheme in light Sn isotopes

International Nuclear Information System (INIS)

Sandulescu, N.; Blomqvist, J.; Liotta, R.J.; Engeland, T.; Hjorth-Jensen, M.; Holt, A.; Osnes, E.

1998-01-01

In the last years the region of light Sn isotopes has been intensively investigated both from experimental and theoretical perspectives. The main goal was to study the excitation mechanisms around the exotic isotope 100 Sn, the heaviest symmetric double magic nucleus which may exist. The simplest approach in analysing the spectra of light tin isotopes is to consider 100 Sn as an inert core and to treat only neutron degrees of freedom in the valence shell N = 50-82. Extensive shell model calculations have been performed on this line. On the other hand, a large part of the light Sn isotopes spectra could be rather well described in terms of simple quasiparticle excitations. Therefore one expects that at least a part of the low-lying states in this region are well approximated in shell-model subspaces with reduced dimensions. An alternative in truncating the shell model space to low-dimensions is the generalized seniority scheme (GSEN). The aim of this letter is to analyse the accuracy of the GSEN scheme for the case of light tin isotopes. In the present calculations we use a microscopically derived interaction. The yrast generalized seniority states are compared with the corresponding shell model states for the case of the tin isotopes 104-112 Sn. For most of the states that agreement is within 100 keV, although the SM space is drastically truncated. For instance, in 110 Sn the number of SM basis states 2 + is 86990, compared with 9 in the case of GSEN. The seniority two states correspond to the particle-number projected QRPA (Quasiparticle Random Phase Approximation) states. One expects the quasiparticle approximations to break down when the number of active nucleons is small. In order to investigate this in the case of light Sn isotopes, we calculated also the energies predicted by QRPA. The agreement of the QRPA with the exact SM result is impressive, even in the case of only few extra-core neutrons. This is due to the large pairing correlations in the high

High-precision isotopic characterization of USGS reference materials by TIMS and MC-ICP-MS

Science.gov (United States)

Weis, Dominique; Kieffer, Bruno; Maerschalk, Claude; Barling, Jane; de Jong, Jeroen; Williams, Gwen A.; Hanano, Diane; Pretorius, Wilma; Mattielli, Nadine; Scoates, James S.; Goolaerts, Arnaud; Friedman, Richard M.; Mahoney, J. Brian

2006-08-01

The Pacific Centre for Isotopic and Geochemical Research (PCIGR) at the University of British Columbia has undertaken a systematic analysis of the isotopic (Sr, Nd, and Pb) compositions and concentrations of a broad compositional range of U.S. Geological Survey (USGS) reference materials, including basalt (BCR-1, 2; BHVO-1, 2), andesite (AGV-1, 2), rhyolite (RGM-1, 2), syenite (STM-1, 2), granodiorite (GSP-2), and granite (G-2, 3). USGS rock reference materials are geochemically well characterized, but there is neither a systematic methodology nor a database for radiogenic isotopic compositions, even for the widely used BCR-1. This investigation represents the first comprehensive, systematic analysis of the isotopic composition and concentration of USGS reference materials and provides an important database for the isotopic community. In addition, the range of equipment at the PCIGR, including a Nu Instruments Plasma MC-ICP-MS, a Thermo Finnigan Triton TIMS, and a Thermo Finnigan Element2 HR-ICP-MS, permits an assessment and comparison of the precision and accuracy of isotopic analyses determined by both the TIMS and MC-ICP-MS methods (e.g., Nd isotopic compositions). For each of the reference materials, 5 to 10 complete replicate analyses provide coherent isotopic results, all with external precision below 30 ppm (2 SD) for Sr and Nd isotopic compositions (27 and 24 ppm for TIMS and MC-ICP-MS, respectively). Our results also show that the first- and second-generation USGS reference materials have homogeneous Sr and Nd isotopic compositions. Nd isotopic compositions by MC-ICP-MS and TIMS agree to within 15 ppm for all reference materials. Interlaboratory MC-ICP-MS comparisons show excellent agreement for Pb isotopic compositions; however, the reproducibility is not as good as for Sr and Nd. A careful, sequential leaching experiment of three first- and second-generation reference materials (BCR, BHVO, AGV) indicates that the heterogeneity in Pb isotopic compositions

Measurement of energy transitions for the decay radiations of 75Ge and 69Ge in a high purity germanium detector

Science.gov (United States)

Aydın, Güral; Usta, Metin; Oktay, Adem

2018-06-01

Photoactivation experiments have a wide range of application areas in nuclear, particle physics, and medical physics such as measuring energy levels and half-lifes of nuclei, experiments for understanding imaging methods in medicine, isotope production for patient treatment, radiation security and transportation, radiation therapy, and astrophysics processes. In this study, some energy transition values of the decay radiations of 75Ge and 69Ge, which are the products of photonuclear reactions (γ, n) with germanium isotopes (75Ge and 69Ge), were measured. The gamma spectrum as a result of atomic transitions were analysed by using a high purity semiconductor germanium detector and the energy transition values which are presented here were compared with the ones which are the best in literature. It was observed that the results presented are in agreement with literature in error range and some results have better precisions.

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

Memories of Professor Sugimoto and isotope separator

International Nuclear Information System (INIS)

Tanaka, Kazuhiro

2013-01-01

Usual magnetic isotope-separators select the particles with the same Z/A value which may include different nuclides. Identification of the isotope with the same Z/A value but different Z or A value is an universal requirement for nuclear physics experiments. If one knows, together with the A/Z value, the dE/dx or the range of the isotope in some energy absorber, which are the function of Z 2 /A, its nuclide can be specified. This idea can be realized by arranging proper energy-absorber at the focal point of magnetic analyzer. The author proposes another novel method in which two dipole-magnets are excited with some difference, and an energy absorber corresponding to that energy difference is situated between two magnets. It can also be devised so that the dispersion at the final focal-point depends only on the emission angle of the isotope at production. Professor Sugimoto recognized the significance of this scheme and proposed to employ it in the experiment at BEVATRON. The unbalanced two dipole-magnets method is employed at RIKEN and RCNP, Osaka University. The author's creative idea originated in Sugimoto Laboratory at Osaka University. (author)

A Hydrogen and He Isotope Nanoprobe

Energy Technology Data Exchange (ETDEWEB)

Doyle, Barney L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Van Deusen, Stuart B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-09-01

Materials that incorporate hydrogen and helium isotopes are of great interest at Sandia and throughout the NNSA and DOE. The Ion Beam Lab at SNL-NM has invented techniques using micron to mm-size MeV ion beams to recoil these light isotopes (Elastic Recoil Detection or ERD) that can very accurately make such measurements. However, there are many measurements that would benefit NW and DOE that require much better resolution, such as the distribution of H isotopes (and 3He) in individual grains of materials relevant to TPBARs, H and He-embrittlement of weapon components important to Tritium Sustainment Programs, issues with GTSs, batteries… Higher resolution would also benefit the field of materials science in general. To address these and many other issues, nm-scale lateral resolution is required. This LDRD demonstrated that neutral H atoms could be recoiled through a thin film by 70 keV electrons and detected with a Channeltron electron multiplier (CEM). The electrons were steered away from the CEM by strong permanent magnets. This proved the feasibility that the high energy electrons from a transmissionelectron- microscope-TEM can potentially be used to recoil and subsequently detect (e-ERD), quantify and map the concentration of H and He isotopes with nm resolution. This discovery could lead to a TEM-based H/He-isotope nanoprobe with 1000x higher resolution than currently available.

Protons scattering on Li isotopes at intermediate energies

International Nuclear Information System (INIS)

Zhusupov, M.A.; Imambekov, O.; Sanfirova, A.V.; Ibraeva, E.T.

2003-01-01

The protons scattering differential cross section on the 6,7,8 Li nuclei are calculated within the framework the Glauber-Sitenko multiple scattering theory at intermediate energies (from 100 to 1000 MeV). In the calculations the multi-cluster wave functions (αt for 7 Li, αnp for 6 Li, and αtn for 8 Li) considering within potential cluster model have been used. Differential cross sections for 6 Li, 7 Li, 8 Li and 9 Li nuclei are similar: absolute cross sections are almost the same, diffraction minimum for large A shifting to the field of the least scattering angles that reflecting increase of the material radius. For the 11 Li the differential cross section absolute value is smaller about in two time than for the rest isotopes. At present it is reliably established, that the 11 Li nucleus has an exotic structure - the nine-nucleon core ( 9 Li) around which the two-neutron halo is rotating. The principal characteristics of the Li nuclei are presented in tabular form

Nuclear Spectroscopy with Copper Isotopes of Extreme N/Z Ratios

CERN Multimedia

La commara, M; Roeckl, E; Van duppen, P L E; Schmidt, K A; Lettry, J

2002-01-01

The collaboration aims to obtain detailed nuclear spectroscopy information on isotopes close to the magic proton number Z=28 Very neutron-rich and neutron-deficient copper isotopes are ionized with the ISOLDE resonance ionization laser ion source (RILIS) to provide beams with low cross contamination.\\\\ \\\\On the neutron-deficient side the high $Q_\\beta$-values of $^{56}$Cu (15~MeV) and $^{57}$Cu (8.8~MeV) allow to study levels at high excitation energies in the doubly magic nucleus $^{56}$Ni and the neighbouring $^{57}$Ni. On the neutron-rich side the spectroscopy with separated copper isotopes allows presently the closest approach to the doubly magic $^{78}$Ni at an ISOL facility. Up to now no suitable target material with a rapid release was found for nickel itself. A slow release behaviour has to be assumed also for the chemically similar elements iron and cobalt.\\\\ \\\\Using a narrow-bandwidth dye laser and tuning of the laser frequency allows to scan the hyperfine splittings of the copper isotopes and isome...

Isotope effects on the optical spectra of semiconductors

Science.gov (United States)

Cardona, Manuel; Thewalt, M. L. W.

2005-10-01

Since the end of the cold war, macroscopic amounts of separated stable isotopes of most elements have been available “off the shelf” at affordable prices. Using these materials, single crystals of many semiconductors have been grown and the dependence of their physical properties on isotopic composition has been investigated. The most conspicuous effects observed have to do with the dependence of phonon frequencies and linewidths on isotopic composition. These affect the electronic properties of solids through the mechanism of electron-phonon interaction, in particular, in the corresponding optical excitation spectra and energy gaps. This review contains a brief introduction to the history, availability, and characterization of stable isotopes, including their many applications in science and technology. It is followed by a concise discussion of the effects of isotopic composition on the vibrational spectra, including the influence of average isotopic masses and isotopic disorder on the phonons. The final sections deal with the effects of electron-phonon interaction on energy gaps, the concomitant effects on the luminescence spectra of free and bound excitons, with particular emphasis on silicon, and the effects of isotopic composition of the host material on the optical transitions between the bound states of hydrogenic impurities.

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

On the origin of cratonic `high-mu' isotopic signatures

Science.gov (United States)

Reimink, J. R.; Carlson, R.; Shirey, S. B.; Pearson, D. G.; Kamber, B. S.

2017-12-01

Some Archean cratons (i.e. Slave, Wyoming) contain Neoarchean granitoids with initial Pb isotopic compositions indicative of derivation from sources characterized by high time-integrated U/Pb ratios (high-mu [1]). Single-stage high-m precursor source reservoir separation from the depleted mantle occurred no later than 3.9 Ga [2]. However, multi-stage separation could have occurred in the Hadean, suggesting that recycling or reworking of Eoarchean/Hadean crust played a significant role in the generation of Neoarchean granitic crust in many cratons. The Sm-Nd system is similar to the U-Pb system in that it has a short-lived parent-daughter pair (146Sm-142Nd) that is sensitive to very early differentiation events, as well as a long-lived parent-daughter pair (147Sm-143Nd) that is sensitive to differentiation throughout all of Earth history. The 103 Ma half-life of 146Sm makes it sensitive only to Sm/Nd fractionation that occurred in the Hadean, providing a useful tracker for very early differentiation events. Indeed, evidence for Neoarchean remelting of ancient crust in another craton has come from analyses of the paired Sm-Nd isotope systems from the Hudson Bay terrane of the northeastern Superior Province. These results indicate that the source of 2.7 Ga Hudson Bay terrane granitoids was Hadean mafic crust, and not Eoarchean felsic crust [3]. Here, we present new data from Neoarchean granites located in the Slave and Wyoming cratons, along with modeling of the dual paired-isotope systems of U-Pb and Sm-Nd to achieve a tighter constraint on the composition of the precursors and the timing of their melting. Combining our newly collected 142Nd data with the high-m signature of these Neoarchean rocks, we evaluate precursor source separation ages along with the source Sm/Nd and U/Pb compositions. In the simplest end-member scenarios, use of the 142Nd system allows us to test whether the cratonic high-mu signature was created by melting of Hadean mafic crust or Eoarchean

Eocene Antarctic seasonality inferred from high-resolution stable isotope profiles of fossil bivalves and driftwood

Science.gov (United States)

Judd, E. J.; Ivany, L. C.; Miklus, N. M.; Uveges, B. T.; Junium, C. K.

2017-12-01

The Eocene Epoch was a time of large-scale global climate change, experiencing both the warmest temperatures of the Cenozoic and the onset of southern hemisphere glaciation. The record of average global temperatures throughout this transition is reasonably well constrained, however considerably less is known about the accompanying changes in seasonality. Seasonally resolved temperature data provide a wealth of information not readily available from mean annual temperature data alone. These data are particularly important in the climatically sensitive high latitudes, as they can elucidate the means by which climate changes and the conditions necessary for the growth of ice sheets. Several recent studies, however, have suggested the potential for monsoonal precipitation regimes in the early-middle Eocene high latitudes, which complicates interpretation of seasonally resolved oxygen isotope records in shallow nearshore marine settings. Seasonal precipitation and runoff could create a brackish, isotopically depleted lens in these environments, depleting summertime δ18Ocarb and thereby inflating the inferred mean and range of isotope-derived temperatures. Here, we assess intra-annual variations in temperature in shallow nearshore Antarctic waters during the middle and late Eocene, inferred from high-resolution oxygen isotope profiles from accretionary bivalves of the La Meseta Formation, Seymour Island, Antarctica. To address concerns related to precipitation and runoff, we also subsample exceptionally preserved fossil driftwood from within the formation and use seasonal differences in δ13Corg values to estimate the ratio of summertime to wintertime precipitation. Late Eocene oxygen isotope profiles exhibit strongly attenuated seasonal amplitudes and more enriched mean annual values in comparison with data from the middle Eocene. Preliminary fossil wood data are not indicative of a strongly seasonal precipitation regime, implying that intra-annual variation in oxygen

Isotopes facilities deactivation project at Oak Ridge National Laboratory

International Nuclear Information System (INIS)

Eversole, R.E.

1997-01-01

The production and distribution of radioisotopes for medical, scientific, and industrial applications has been a major activity at Oak Ridge National Laboratory (ORNL) since the late 1940s. As the demand for many of these isotopes grew and their sale became profitable, the technology for the production of the isotopes was transferred to private industry, and thus, many of the production facilities at ORNL became underutilized. In 1989, the U.S. Department of Energy (DOE) instructed ORNL to identify and prepare various isotopes production facilities for safe shutdown. In response, ORNL identified 19 candidate facilities for shutdown and established the Isotopes Facilities Shutdown Program. In 1993, responsibility for the program was transitioned from the DOE Office of Nuclear Energy to the DOE Office of Environmental Management and Uranium Enrichment Operation's Office of Facility Transition and Management. The program was retitled the Isotopes Facilities Deactivation Project (IFDP), and implementation responsibility was transferred from ORNL to the Lockheed Martin Energy Systems, Inc. (LMES), Environmental Restoration (ER) Program

Isotopes facilities deactivation project at Oak Ridge National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Eversole, R.E.

1997-05-01

The production and distribution of radioisotopes for medical, scientific, and industrial applications has been a major activity at Oak Ridge National Laboratory (ORNL) since the late 1940s. As the demand for many of these isotopes grew and their sale became profitable, the technology for the production of the isotopes was transferred to private industry, and thus, many of the production facilities at ORNL became underutilized. In 1989, the U.S. Department of Energy (DOE) instructed ORNL to identify and prepare various isotopes production facilities for safe shutdown. In response, ORNL identified 19 candidate facilities for shutdown and established the Isotopes Facilities Shutdown Program. In 1993, responsibility for the program was transitioned from the DOE Office of Nuclear Energy to the DOE Office of Environmental Management and Uranium Enrichment Operation`s Office of Facility Transition and Management. The program was retitled the Isotopes Facilities Deactivation Project (IFDP), and implementation responsibility was transferred from ORNL to the Lockheed Martin Energy Systems, Inc. (LMES), Environmental Restoration (ER) Program.

Neutron resonance transmission spectroscopy with high spatial and energy resolution at the J-PARC pulsed neutron source

Energy Technology Data Exchange (ETDEWEB)

Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Shinohara, T.; Kai, T.; Ooi, M. [Japan Atomic Energy Agency, 2–4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kamiyama, T.; Kiyanagi, Y.; Shiota, Y. [Hokkaido University, Kita 13 Nishi 8 Kita-ku, Sapporo-shi, Hokkaido 060-8628 (Japan); McPhate, J.B.; Vallerga, J.V.; Siegmund, O.H.W. [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Rd., Sturbridge, MA 01566 (United States)

2014-05-11

The sharp variation of neutron attenuation at certain energies specific to particular nuclides (the lower range being from ∼1 eV up to ∼1 keV), can be exploited for the remote mapping of element and/or isotope distributions, as well as temperature probing, within relatively thick samples. Intense pulsed neutron beam-lines at spallation sources combined with a high spatial, high-timing resolution neutron counting detector, provide a unique opportunity to measure neutron transmission spectra through the time-of-flight technique. We present the results of experiments where spatially resolved neutron resonances were measured, at energies up to 50 keV. These experiments were performed with the intense flux low background NOBORU neutron beamline at the J-PARC neutron source and the high timing resolution (∼20 ns at epithermal neutron energies) and spatial resolution (∼55 µm) neutron counting detector using microchannel plates coupled to a Timepix electronic readout. Simultaneous element-specific imaging was carried out for several materials, at a spatial resolution of ∼150 µm. The high timing resolution of our detector combined with the low background beamline, also enabled characterization of the neutron pulse itself – specifically its pulse width, which varies with neutron energy. The results of our measurements are in good agreement with the predicted results for the double pulse structure of the J-PARC facility, which provides two 100 ns-wide proton pulses separated by 600 ns, broadened by the neutron energy moderation process. Thermal neutron radiography can be conducted simultaneously with resonance transmission spectroscopy, and can reveal the internal structure of the samples. The transmission spectra measured in our experiments demonstrate the feasibility of mapping elemental distributions using this non-destructive technique, for those elements (and in certain cases, specific isotopes), which have resonance energies below a few keV, and with lower

High-Throughput Method for Strontium Isotope Analysis by Multi-Collector-Inductively Coupled Plasma-Mass Spectrometer

Energy Technology Data Exchange (ETDEWEB)

Wall, Andrew J. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Capo, Rosemary C. [Univ. of Pittsburgh, PA (United States); Stewart, Brian W. [Univ. of Pittsburgh, PA (United States); Phan, Thai T. [Univ. of Pittsburgh, PA (United States); Jain, Jinesh C. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Hakala, Alexandra [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Guthrie, George D. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

2016-09-22

This technical report presents the details of the Sr column configuration and the high-throughput Sr separation protocol. Data showing the performance of the method as well as the best practices for optimizing Sr isotope analysis by MC-ICP-MS is presented. Lastly, this report offers tools for data handling and data reduction of Sr isotope results from the Thermo Scientific Neptune software to assist in data quality assurance, which help avoid issues of data glut associated with high sample throughput rapid analysis.

High-Throughput Method for Strontium Isotope Analysis by Multi-Collector-Inductively Coupled Plasma-Mass Spectrometer

Energy Technology Data Exchange (ETDEWEB)

Hakala, Jacqueline Alexandra [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

2016-11-22

This technical report presents the details of the Sr column configuration and the high-throughput Sr separation protocol. Data showing the performance of the method as well as the best practices for optimizing Sr isotope analysis by MC-ICP-MS is presented. Lastly, this report offers tools for data handling and data reduction of Sr isotope results from the Thermo Scientific Neptune software to assist in data quality assurance, which help avoid issues of data glut associated with high sample throughput rapid analysis.

Plutonium isotopic composition of high burnup spent fuel discharged from light water reactors

International Nuclear Information System (INIS)

Nakano, Yoshihiro; Okubo, Tsutomu

2011-01-01

Highlights: → Pu isotopic composition of fuel affects FBR core nuclear characteristics very much. → Spent fuel compositions of next generation LWRs with burnup of 70 GWd/t were obtained. → Pu isotopic composition and amount in the spent fuel with 70 GWd/t were evaluated. → Spectral shift rods of high burnup BWR increases the fissile Pu fraction of spent fuel. → Wide fuel rod pitch of high burnup PWR lowers the fissile Pu fraction of spent fuel. - Abstract: The isotopic composition and amount of plutonium (Pu) in spent fuel from a high burnup boiling water reactor (HB-BWR) and a high burnup pressurized water reactor (HB-PWR), each with an average discharge burnup of 70 GWd/t, were estimated, in order to evaluate fast breeder reactor (FBR) fuel composition in the transition period from LWRs to FBRs. The HB-BWR employs spectral shift rods and the neutron spectrum is shifted through the operation cycle. The weight fraction of fissile plutonium (Puf) isotopes to the total plutonium in HB-BWR spent fuel after 5 years cooling is 62%, which is larger than that of conventional BWRs with average burnup of 45 GWd/t, because of the spectral shift operation. The amount of Pu produced in the HB-BWR is also larger than that produced in a conventional BWR. The HB-PWR uses a wider pitch 17 x 17 fuel rod assembly to optimize neutron slowing down. The Puf fraction of HB-PWR spent fuel after 5 years cooling is 56%, which is smaller than that of conventional PWRs with average burnup of 49 GWd/t, mainly because of the wider pitch. The amount of Pu produced in the HB-PWR is also smaller than that in conventional PWRs.

Application of helium isotopes in shallow groundwaters for geothermal energy exploration in the Upper Rhine Graben

Energy Technology Data Exchange (ETDEWEB)

Freundt, Florian

2017-07-12

The helium isotope system is an established tool in hydrology for identifying mantle fluids in deep aquifers. This study applies the helium tracer system for the first time in shallow, unconfined aquifers of the Upper Rhine Graben. The Graben is a part of the Cenozoic Rift system of Western and Central Europe, a continental rift zone with unusually high geothermal gradients, making it an ideal region of Germany for geothermal energy development. The aim of this study is to develop a suite of natural groundwater tracers able to achieve a cost and effort reduction in geothermal prospection. The {sup 3}He/{sup 4}He-ratio is therefore applied, as part of a multi-tracer approach including {sup 3}H, δ{sup 18}O, δ{sup 2}H, δ{sup 13}C, {sup 14}C and {sup 222}Rn, to identify and locate fault zones with suitable permeabilities for power plant operation. Three target areas along the graben were studied, each located on one of the main fault lines. A mantle-derived helium signature could be identified and separated from tritiogenic helium in a shallow aquifer in the north-west of the Graben. The mixing component of mantle-derived fluid in the shallow groundwater is calculated to reach up to 5%, based on the analysis of the {sup 3}He/{sup 4}He isotope system. The employed method proves that the local permeability of the fault zone is high. The origin of the locally occurring upwelling of salinated water can be redetermined by the data.

Kinetic isotope effects in the CH4 + H→CH3 + H2 system. Predictions of the LMR six-body potential-energy reaction hypersurface

International Nuclear Information System (INIS)

Marriott, T.D.

1976-01-01

Scope of Study: The purpose of this study was two-fold. First, it served to test, in part, the usefulness of the LMR six-body potential-energy surface (LMR-PES) for transition-state theory predictions of the kinetic isotope effects for both the forward and reverse reactions of CH 4 + H reversible CH 3 + H 2 . In this regard the agreement between experimental and theoretical isotope effects, assuming the former to be accurate, provides information about the accuracy of the curvature of the potential energy surface for motion both parallel and perpendicular to the reaction coordinate. Second, these isotope effects were used to assess the validity of a number of qualitative and semi-quantitative interpretations of kinetic isotope effects developed in physical organic chemistry with regard to this reaction system. The force constants and geometries obtained numerically from the LMR-PES were found to produce reasonable harmonic approximations to the reactant normal mode frequencies. Neglecting tunneling, the LMR-PES reasonably reproduces the experimental k/sub H//k/sub D/ values for the reactions CH 4 + H(D), CH 3 + HD(DH) and CD 2 + HD(DH). Since previous theoretical treatments of primary deuterium kinetic isotope effects have neglected the bending normal mode frequencies, a semi-quantitative study of the effect of neglecting bending frequencies on the VP, EXC, and ZPE elements as well as the transition-state theory kinetic isotope effects was performed. The Swain-Schaad relationship between primary deuterium and tritium kinetic isotope effects was shown to hold to a reasonable degree of accuracy for the LMR-PES reaction system. A relationship between 13-carbon and 14-carbon kinetic isotope effects similar to the Swain-Schaad relationship was derived

A novel nuclear pyrometry for the characterization of high-energy bremsstrahlung and electrons produced in relativistic laser-plasma interactions

International Nuclear Information System (INIS)

Guenther, M. M.; Sonnabend, K.; Harres, K.; Roth, M.; Brambrink, E.; Vogt, K.; Bagnoud, V.

2011-01-01

We present a novel nuclear activation-based method for the investigation of high-energy bremsstrahlung produced by electrons above 7 MeV generated by a high-power laser. The main component is a novel high-density activation target that is a pseudo alloy of several selected isotopes with different photo-disintegration reaction thresholds. The gamma spectrum emitted by the activated targets is used for the reconstruction of the bremsstrahlung spectrum using an analysis method based on Penfold and Leiss. This nuclear activation-based technique allows for the determination of the number of bremsstrahlung photons per energy bin in a wide range energy without any anticipated fit procedures. Furthermore, the analysis method also allows for the determination of the absolute yield, the energy distribution, and the temperature of high-energy electrons at the relativistic laser-plasma interaction region. The pyrometry is sensitive to energies above 7 MeV only, i.e., this diagnostic is insensitive to any low-energy processes.

A novel nuclear pyrometry for the characterization of high-energy bremsstrahlung and electrons produced in relativistic laser-plasma interactions

Energy Technology Data Exchange (ETDEWEB)

Guenther, M. M.; Sonnabend, K.; Harres, K.; Roth, M. [Institut fuer Kernphysik, Schlossgartenstr. 9, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Brambrink, E. [Laboratoire pour l' Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-Ecole Polytechnique-Universite Paris VI, F-91128 Palaiseau (France); Vogt, K.; Bagnoud, V. [GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, D-64291 Darmstadt (Germany)

2011-08-15

We present a novel nuclear activation-based method for the investigation of high-energy bremsstrahlung produced by electrons above 7 MeV generated by a high-power laser. The main component is a novel high-density activation target that is a pseudo alloy of several selected isotopes with different photo-disintegration reaction thresholds. The gamma spectrum emitted by the activated targets is used for the reconstruction of the bremsstrahlung spectrum using an analysis method based on Penfold and Leiss. This nuclear activation-based technique allows for the determination of the number of bremsstrahlung photons per energy bin in a wide range energy without any anticipated fit procedures. Furthermore, the analysis method also allows for the determination of the absolute yield, the energy distribution, and the temperature of high-energy electrons at the relativistic laser-plasma interaction region. The pyrometry is sensitive to energies above 7 MeV only, i.e., this diagnostic is insensitive to any low-energy processes.

Raman spectroscopic studies of isotopic diatomic molecules and a technique for measuring stable isotope ratios using Raman scattering

International Nuclear Information System (INIS)

Harney, R.C.

1976-01-01

A method for measuring stable isotope ratios using Raman scattering has been developed. This method consists of simultaneously counting photons scattered out of a high-intensity laser beam by different isotopically-substituted molecules. A number of studies of isotopic diatomic molecules have been made. The Q-branches of the Raman spectra of the isotopic molecules 14 N 15 N and 16 O 18 O were observed at natural abundance in nitrogen and oxygen samples. Comparison of the ratios of the intensities of the Q-branches of the major nitrogen and oxygen isotopic molecules with mass spectrometric determinations of the isotopic compositions yielded scattering cross sections of 14 N 15 N relative to 14 N 14 N and 16 O 18 O relative to 16 O 16 O. These cross section ratios differ from unity, a difference which can be explained by considering nuclear mass effects on the Franck-Condon factors of the molecular transitions. The measured intensities of the 14 N 15 N and 16 O 18 O Q-branches provided the baseline data needed to make the previously-mentioned extrapolation. High-resolution (approximately 0.15 cm -1 ) spectra of the Q-branches of 14 N 14 N and 16 O 16 O yielded a direct determination of α/sub e/ (the difference between the rotational constant in the ground and first excited vibrational states) for these molecules. The measured values are in excellent agreement with those obtained by other means. Complete Raman spectra (pure rotation, rotation-vibration, and high-resolution Q-branch) were obtained on a sample of pure 18 O 18 O. Analysis of this data yielded the molecular parameters: the equilibrium internuclear separation r/sub e/, the moment of inertia I/sub e/, and the energy parameters α/sub e/, B/sub e/, and ΔG/sub 1 / 2 /. These are in good agreement with data obtained by microwave spectroscopy

MEASUREMENTS OF COSMIC-RAY HYDROGEN AND HELIUM ISOTOPES WITH THE PAMELA EXPERIMENT

Energy Technology Data Exchange (ETDEWEB)

Adriani, O.; Bongi, M. [University of Florence, Department of Physics, I-50019 Sesto Fiorentino, Florence (Italy); Barbarino, G. C. [University of Naples “Federico II,” Department of Physics, I-80126 Naples (Italy); Bazilevskaya, G. A. [Lebedev Physical Institute, RU-119991, Moscow (Russian Federation); Bellotti, R.; Bruno, A. [University of Bari, Department of Physics, I-70126 Bari (Italy); Boezio, M.; Bonvicini, V.; Formato, V. [INFN, Sezione di Trieste, I-34149 Trieste (Italy); Bogomolov, E. A. [Ioffe Physical Technical Institute, RU-194021 St. Petersburg (Russian Federation); Bottai, S. [INFN, Sezione di Florence, I-50019 Sesto Fiorentino, Florence (Italy); Cafagna, F. [INFN, Sezione di Bari, I-70126 Bari (Italy); Campana, D. [INFN, Sezione di Naples, I-80126 Naples (Italy); Carlson, P. [KTH, Department of Physics, and the Oskar Klein Centre for Cosmoparticle Physics, AlbaNova University Centre, SE-10691 Stockholm (Sweden); Casolino, M.; Santis, C. De [University of Rome “Tor Vergata,” Department of Physics, I-00133 Rome (Italy); Castellini, G. [IFAC, I-50019 Sesto Fiorentino, Florence (Italy); Donato, C. De; Simone, N. De; Felice, V. Di [INFN, Sezione di Rome “Tor Vergata,” I-00133 Rome (Italy); and others

2016-02-10

The cosmic-ray hydrogen and helium ({sup 1}H, {sup 2}H, {sup 3}He, {sup 4}He) isotopic composition has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on board the Resurs-DK1 satellite on 2006 June 15. The rare isotopes {sup 2}H and {sup 3}He in cosmic rays are believed to originate mainly from the interaction of high-energy protons and helium with the galactic interstellar medium. The isotopic composition was measured between 100 and 1100 MeV/n for hydrogen and between 100 and 1400 MeV/n for helium isotopes using two different detector systems over the 23rd solar minimum from 2006 July to 2007 December.

Non-statistical effects in the radiative capture cross sections of the neodymium isotopes

International Nuclear Information System (INIS)

Musgrove, A.R.; Allen, B.J.; Boldeman, J.W.

1977-01-01

The neutron capture cross sections of the stable neodymium isotopes have been measured with high energy resolution in the keV region at the 40 m station of ORELA. Average resonance parameters are extracted for s-wave resonances. Significant positive correlations are found between gamma-n-0 and gamma-gamma for all isotopes. The magnitude of the observed correlation coefficient, particularly for 142 Nd (rho = 0.9), cannot be explained in terms of valence neutron capture and additional mechanisms are discussed. The average s-wave radiative widths for the odd-A isotopes are markedly greater than for the even-A isotopes, while the p-wave radiative width for 142 Nd is considerably less than the s-wave width. (author)

Computer-controlled detection system for high-precision isotope ratio measurements

International Nuclear Information System (INIS)

McCord, B.R.; Taylor, J.W.

1986-01-01

In this paper the authors describe a detection system for high-precision isotope ratio measurements. In this new system, the requirement for a ratioing digital voltmeter has been eliminated, and a standard digital voltmeter interfaced to a computer is employed. Instead of measuring the ratio of the two steadily increasing output voltages simultaneously, the digital voltmeter alternately samples the outputs at a precise rate over a certain period of time. The data are sent to the computer which calculates the rate of charge of each amplifier and divides the two rates to obtain the isotopic ratio. These results simulate a coincident measurement of the output of both integrators. The charge rate is calculated by using a linear regression method, and the standard error of the slope gives a measure of the stability of the system at the time the measurement was taken

Isotopic analysis of uranium hexafluoride highly enriched in U-235

International Nuclear Information System (INIS)

Chaussy, L.; Boyer, R.

1968-01-01

Isotopic analysis of uranium in the form of the hexafluoride by mass-spectrometry gives gross results which are not very accurate. Using a linear interpolation method applied to two standards it is possible to correct for this inaccuracy as long as the isotopic concentrations are less than about 10 per cent in U-235. Above this level, the interpolations formula overestimates the results, especially if the enrichment of the analyzed samples is higher than 1.3 with respect to the standards. A formula is proposed for correcting the interpolation equation and for the extending its field of application to high values of the enrichment (≅2) and of the concentration. It is shown that by using this correction the results obtained have an accuracy which depends practically only on that of the standards, taking into account the dispersion in the measurements. (authors) [fr

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)

High energy radiation in cancer treatment

Energy Technology Data Exchange (ETDEWEB)

NONE

1959-10-15

Certain basic recommendations on the use of supervoltage radiation and radioisotope teletherapy in the treatment of malignant growths have been made by an expert study group which met in Vienna in August this y ear. The group, convened jointly by the International Atomic Energy Agency and the World Health Organization, was composed of 20 radiotherapists and radiation physicists from 12 countries. High energy radiation, used in the treatment of malignant tumours, can be either in the form of gamma- or X-rays or in the form of beams of accelerated electrons. The source of radiation is kept at a certain distance from the patient. The study group was agreed on the value of supervoltage radiotherapy, including gamma-ray and high voltage x-ray therapy as well as electron beam therapy. The required gamma radiation can be obtained from large sources of radioactive materials like cobalt 60 or caesium 137, while electron beams are produced by high voltage accelerators. The experts considered the sources in four broad categories: large supervoltage units, intermediate units, small isotope units and units of electron beams or very high energy x-rays. Each group of source was described including its usage. The experts made it clear that while supervoltage radiation should be a part of an organized radiotherapy department, the radiation facilities at any particular establishment should not be of the supervoltage type alone. The high energy facilities could be fruitfully used only when there was a background of general radiotherapy. The group emphasized that supervoltage radiotherapy, in common with other forms of radiotherapy, should be conducted only by adequately trained and qualified personnel, including radiation physicists, and specified the training and qualifications required of such personnel. It was felt that specialized training was one of the main requirements at the present stage and the training programmes of IAEA and WHO should be utilized extensively for this

High energy radiation in cancer treatment

International Nuclear Information System (INIS)

1959-01-01

Certain basic recommendations on the use of supervoltage radiation and radioisotope teletherapy in the treatment of malignant growths have been made by an expert study group which met in Vienna in August this y ear. The group, convened jointly by the International Atomic Energy Agency and the World Health Organization, was composed of 20 radiotherapists and radiation physicists from 12 countries. High energy radiation, used in the treatment of malignant tumours, can be either in the form of gamma- or X-rays or in the form of beams of accelerated electrons. The source of radiation is kept at a certain distance from the patient. The study group was agreed on the value of supervoltage radiotherapy, including gamma-ray and high voltage x-ray therapy as well as electron beam therapy. The required gamma radiation can be obtained from large sources of radioactive materials like cobalt 60 or caesium 137, while electron beams are produced by high voltage accelerators. The experts considered the sources in four broad categories: large supervoltage units, intermediate units, small isotope units and units of electron beams or very high energy x-rays. Each group of source was described including its usage. The experts made it clear that while supervoltage radiation should be a part of an organized radiotherapy department, the radiation facilities at any particular establishment should not be of the supervoltage type alone. The high energy facilities could be fruitfully used only when there was a background of general radiotherapy. The group emphasized that supervoltage radiotherapy, in common with other forms of radiotherapy, should be conducted only by adequately trained and qualified personnel, including radiation physicists, and specified the training and qualifications required of such personnel. It was felt that specialized training was one of the main requirements at the present stage and the training programmes of IAEA and WHO should be utilized extensively for this

Generator Coordinate Method Analysis of Xe and Ba Isotopes

Science.gov (United States)

Higashiyama, Koji; Yoshinaga, Naotaka; Teruya, Eri

Nuclear structure of Xe and Ba isotopes is studied in terms of the quantum-number projected generator coordinate method (GCM). The GCM reproduces well the energy levels of high-spin states as well as low-lying states. The structure of the low-lying states is analyzed through the GCM wave functions.

A new high-quality set of singly (H-2) and doubly (H-2 and O-18) stable isotope labeled reference waters for biomedical and other isotope-labeled research

NARCIS (Netherlands)

Faghihi, V.; Verstappen-Dumoulin, B. M. A. A.; Jansen, H. G.; van Dijk, G.; Aerts-Bijma, A. T.; Kerstel, E. R. T.; Groening, M.; Meijer, H. A. J.

2015-01-01

RATIONALE: Research using water with enriched levels of the rare stable isotopes of hydrogen and/or oxygen requires well-characterized enriched reference waters. The International Atomic Energy Agency (IAEA) did have such reference waters available, but these are now exhausted. New reference waters

Isotopic chemical weathering behaviour of Pb derived from a high-Alpine Holocene lake-sediment record

Science.gov (United States)

Gutjahr, Marcus; Süfke, Finn; Gilli, Adrian; Anselmetti, Flavio; Glur, Lukas; Eisenhauer, Anton

2017-04-01

Several studies assessing the chemical weathering systematics of Pb isotopes provided evidence for the incongruent release of Pb from source rocks during early stages of chemical weathering, resulting in runoff compositions more radiogenic (higher) than the bulk source-rock composition [e.g. 1]. Deep NW Atlantic seawater Pb isotope records covering the last glacial-interglacial transition further support these findings. Clear excursions towards highly radiogenic Pb isotopic input in the deep NW Atlantic seen during the early Holocene, hence after the large-scale retreat of the Laurentide Ice Sheet in North America, are interpreted to be controlled by preferential release of radiogenic Pb from U- and Th-rich mineral phases during early stages of chemical weathering that are less resistant to chemical dissolution than other rock-forming mineral phases [2-4]. To date, however, no terrestrial Pb isotope record exists that could corroborate the evidence from deep marine sites for efficient late deglacial weathering and washout of radiogenic Pb. We present a high-resolution adsorbed Pb isotope record from a sediment core retrieved from Alpine Lake Grimsel (1908 m.a.s.l.) in Switzerland, consisting of 117 Pb compositions over the past 10 kyr. This high-Alpine study area is ideally located for incipient and prolonged chemical weathering studies. The method used to extract the adsorbed lake Pb isotope signal is identical to previous marine approaches targeting the authigenic Fe-Mn oxyhydroxides fraction within the lake sediments [5, 6]. The Pb isotope compositions are further accompanied by various elemental ratios derived from the same samples that equally trace climatic boundary conditions in the Grimsel Lake area. The Pb isotopic composition recorded in Lake Grimsel is remarkably constant throughout the majority of the Holocene until ˜2.5 ka BP, despite variable sediment composition and -age, and isotopically relatively close to the signature of the granitic source rock

Nuclear structure of light Ca and heavy Cr isotopes

International Nuclear Information System (INIS)

Buerger, A.

2007-01-01

In the present thesis, the shell structure in exotic nuclei has been investigated. The focus of the work was on finding new experimental data in neutron-rich Cr and proton-rich Ca isotopes. The investigation of light Ca isotopes concentrated on the nucleus 36 Ca which was produced in a knockout reaction from a radioactive 37 Ca beam. For 36 Ca, the excitation energy of the first 2 + state has been measured for the first time. Furthermore, momentum distributions were analyzed using a Monte-Carlo simulation of the knockout reaction. This analysis yielded the contributions of neutrons from individual orbitals to the total knockout cross section. In principle, these may be used to calculate spectroscopic factors, but such a calculation is hampered by difficulties of present knockout-reaction models in predicting precise single-particle cross sections. The measured branching ratio to the ground and excited states, on the other hand, is close to the predicted value. A remaining difference might be due to emission of protons which cannot be detected with the present experimental setup. Both the branching ratio and the large excitation energy are compatible with a large N=16 gap in 36 Ca that leads to relatively pure configurations both in the ground state and the excited 2 + state. As a by-product of the experiment, two excitation energies in the T=2 nuclei 32 Ar and 28 S have been confirmed, and two γ-ray transitions have been observed for the first time in 37 Ca. While the mirror energy differences in the T=2 pairs 36 Ca- 36 S, 32 Ar- 32 Si, and 28 S- 28 Mg can be reproduced in shell model calculations using a modified USD interaction, these modifications are not sufficient to explain the mirror energy differences for the pair 37 Ca- 37 Cl. In the heavy Cr isotopes, new experimental evidence for a sub-shell closure at N=32 was found in a measurement of B(E2) values using high-energy Coulomb excitation of radioactive beams. Prior to this experiment, the assumption of a

Atomic masses of rare-earth isotopes

International Nuclear Information System (INIS)

Schmidt-Ott, W.D.; Kantus, R.; Runte, E.

1981-01-01

A survey is given of decay energies of rare-earth isotopes measured in electron-capture decay by relative Psub(K) ratios, ECsub(K)/β + , and EC/β + ratios. Atomic masses of A = 147 isotopes and of 146 Gd and 148 Dy were derived. The masses of these isotopes and of α-decaying precessors are compared with predictions of current mass formulae. The subshell closure at Z = 64 is shown for N = 82, and 84 isotones. (orig.)

Study on isotopic distribution produced by nucleus-nucleus collisions with modified SAA model

International Nuclear Information System (INIS)

Zhong Chen; Fang Deqing; Cai Xiangzhou; Shen Wenqing; Zhang Huyong; Wei Yibin; Ma Yugang

2003-01-01

Base on Brohm's Statistic-Ablation-Abrasion (SAA) model, the modified SAA model was developed via introducing the isospin dependence of nucleon distribution in nucleus and parameterized formulas for nucleon-nucleon cross section in nuclear matter. It can simulate well the isotopic distribution at both high and intermediate energies. By the improvement of computational method, the range of calculation of isotopic distribution can be increased from three order magnitude to eight order magnitude (even higher). It can reproduce experimental data and predict the isotopic distribution for very far from stability line which is very important from experimental viewpoint

The cosmic ray and solar flare isotope experiments in the CRRES, NOAA-I and ''Ulysses'' satellites

International Nuclear Information System (INIS)

Garcia-Munoz, M.

1990-01-01

The ONR-604 instrument has been designed to measure the energy spectra and the isotopic composition at 1 AU of the elements Hydrogen to Nickel in the energy range 40--500 MeV/n and will be carried by the Combined Release and Radiation Effects Satellite (CRRES) to be launched July, 1990 in a highly eccentric orbit between a low perigee and a synchronous orbit point. It will measure galactic cosmic rays, solar energetic particles, and trapped and pseudo-trapped particles in the Earth magnetosphere. Also at 1 AU, the Energetic Heavy Ion Composition (EHIC) instrument, designed to study mainly the elemental and isotopic composition of solar energetic particles over the charge range H to Ni, in the energy range 0.5 to 200 MeV/n, will be placed in a Sun-synchronous circular polar orbit of 833 or 870 km altitude by a NOAA-I satellite scheduled to be launched late 1990 or early 1991. The University of Chicago High Energy Telescope (HET) experiment which is part of the COSPIN consortium on the ''Ulysses'' mission will measure the energy spectra and the isotopic composition of the elments Hydrogen to Nickel in the energy interval 20--450 MeV/n in the heliosphere, both the ecliptic plane and at high heliographic latitudes in an orbit around the Sun that will have an aphelion near a Jupiter orbit point and a perhelion of about 1.4 AU. It will be launched October 1990

High-power CO laser with RF discharge for isotope separation employing condensation repression

Science.gov (United States)

Baranov, I. Ya.; Koptev, A. V.

2008-10-01

High-power CO laser can be the effective tool in such applications as isotope separation using the free-jet CRISLA method. The way of transfer from CO small-scale experimental installation to industrial high-power CO lasers is proposed through the use of a low-current radio-frequency (RF) electric discharge in a supersonic stream without an electron gun. The calculation model of scaling CO laser with RF discharge in supersonic stream was developed. The developed model allows to calculate parameters of laser installation and optimize them with the purpose of reception of high efficiency and low cost of installation as a whole. The technical decision of industrial CO laser for isotope separation employing condensation repression is considered. The estimated cost of laser is some hundred thousand dollars USA and small sizes of laser head give possibility to install it in any place.

A simplified method for obtaining high-purity perchlorate from groundwater for isotope analyses.

Energy Technology Data Exchange (ETDEWEB)

vonKiparski, G; Hillegonds, D

2011-04-04

Investigations into the occurrence and origin of perchlorate (ClO{sub 4}{sup -}) found in groundwater from across North America have been sparse until recent years, and there is mounting evidence that natural formation mechanisms are important. New opportunities for identifying groundwater perchlorate and its origin have arisen with the utilization of improved detection methods and sampling techniques. Additionally, application of the forensic potential of isotopic measurements has begun to elucidate sources, potential formation mechanisms and natural attenuation processes. Procedures developed appear to be amenable to enable high precision stable isotopic analyses, as well as lower precision AMS analyses of {sup 36}Cl. Immediate work is in analyzing perchlorate isotope standards and developing full analytical accuracy and uncertainty expectations. Field samples have also been collected, and will be analyzed when final qa/qc samples are deemed acceptable.

New isotopes of elements 104, 106 and 108 - highly stable superheavy nuclei

International Nuclear Information System (INIS)

Oganessian, Yuri

1994-01-01

In April 1993, as part of a joint Dubna-Livermore experiment at the Flerov Laboratory of Nuclear Reactions, new heavy isotopes of elements 104 and 106 were synthesized - 262 104, 265 106 and 266 106. Compared with the known even-even isotopes of elements 104 and 106, the new nuclei are characterized by their extraordinary high resistance to spontaneous fission. This is a direct proof of the macro-microscopic theory predictions in its version calculated by A.Sobiczewski et al. regarding a substantial increase in the half-lives of heavy nuclei near deformed shells with atomic number (Z) 108 and neutron number (N) 162.

Derivation of Apollo 14 High-Al Basalts at Discrete Times: Rb-Sr Isotopic Constraints

Science.gov (United States)

Hui. Hejiu; Neal, Clive, R.; Shih, Chi-Yu; Nyquist, Laurence E.

2012-01-01

Pristine Apollo 14 (A-14) high-Al basalts represent the oldest volcanic deposits returned from the Moon [1,2] and are relatively enriched in Al2O3 (>11 wt%) compared to other mare basalts (7-11 wt%). Literature Rb-Sr isotopic data suggest there are at least three different eruption episodes for the A-14 high-Al basalts spanning the age range approx.4.3 Ga to approx.3.95 Ga [1,3]. Therefore, the high-Al basalts may record lunar mantle evolution between the formation of lunar crust (approx.4.4 Ga) and the main basin-filling mare volcanism (groups [5,6], and then regrouped into three with a possible fourth comprising 14072 based on the whole-rock incompatible trace element (ITE) ratios and Rb-Sr radiometric ages [7]. However, Rb-Sr ages of these basalts from different laboratories may not be consistent with each other because of the use of different 87Rb decay constants [8] and different isochron derivation methods over the last four decades. This study involved a literature search for Rb-Sr isotopic data previously reported for the high-Al basalts. With the re-calculated Rb-Sr radiometric ages, eruption episodes of A-14 high-Al basalts were determined, and their petrogenesis was investigated in light of the "new" Rb-Sr isotopic data and published trace element abundances of these basalts.

The isospin dependence of the nucleus-nucleus inelastic cross-section at high energy

International Nuclear Information System (INIS)

Rashdan, M.; Farhan, A.M.; Hassib, E.; Kareem, W. Abdel

2006-01-01

The isospin dependence of the nucleus-nucleus inelastic cross-section at high energy is investigated within the multiple scattering theory. The multiple integrals are evaluated by Monte Carlo method as well as by the optical limit approximation of the Glauber model. Calculations are performed for 14-23 N, 16-24 O and 18-26 F isotopes colliding with carbon target around 1 GeV. It is found that rms radii and the density distributions show a halo structure of 22 N, 23 O and 24 F

Isotopic scaling of transport in deuterium-tritium plasmas

International Nuclear Information System (INIS)

Scott, S.D.; Adler, H.; Bell, M.G.; Bell, R.; Budny, R.V.; Bush, C.E.; Chang, Z.; Duong, H.

1995-01-01

Both global and thermal energy confinement improve in high-temperature supershot plasmas in the Tokamak Fusion Test Reactor (TFTR) when deuterium beam heating is partially or wholly replaced by tritium beam heating. For the same heating power, the tritium-rich plasmas obtain up to 22% higher total energy, 30% higher thermal ion energy, and 20-25% higher central ion temperature. Kinetic analysis of the temperature and density profiles indicates a favorable isotopic scaling of ion heat transport and electron particle transport, with τ Ei (a/2) ∝ (A) 0.7-0.8 and τ pe (a) ∝ (A) 0.8

Kinetics of isotopic exchange between strontium polymolybdate and strontium ions in aqueous solution

International Nuclear Information System (INIS)

Atun, Gulten; Bilgin, Binay; Kilislioglu, Ayben

2002-01-01

A heterogeneous isotopic exchange reaction of strontium polymolybdate in strontium chloride solution was studied using 90 Sr as a tracer. The effects of low and high strontium chloride concentration on the rate and mechanism of the isotopic exchange reaction were investigated. It was found that, at high concentrations, the rate is independent of strontium concentration, but, at low concentrations, the rate is proportional to the strontium concentration. These results support a hypothesis that, at low concentrations, the rate is controlled by film diffusion, whereas at high concentrations it is controlled by particle diffusion. Experiments were performed at 293, 303 and 313 K. Activation energy of isotopic exchange reaction and thermodynamic parameters ΔH*, ΔS*, and ΔG* were calculated using the Arrhenius and Eyring equations. The results also indicated that recrystallization is a predominant factor in the present exchange reaction

Kinetics of isotopic exchange between strontium polymolybdate and strontium ions in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Atun, Gulten E-mail: gultena@istanbul.edu.tr; Bilgin, Binay; Kilislioglu, Ayben

2002-06-01

A heterogeneous isotopic exchange reaction of strontium polymolybdate in strontium chloride solution was studied using {sup 90}Sr as a tracer. The effects of low and high strontium chloride concentration on the rate and mechanism of the isotopic exchange reaction were investigated. It was found that, at high concentrations, the rate is independent of strontium concentration, but, at low concentrations, the rate is proportional to the strontium concentration. These results support a hypothesis that, at low concentrations, the rate is controlled by film diffusion, whereas at high concentrations it is controlled by particle diffusion. Experiments were performed at 293, 303 and 313 K. Activation energy of isotopic exchange reaction and thermodynamic parameters {delta}H*, {delta}S*, and {delta}G* were calculated using the Arrhenius and Eyring equations. The results also indicated that recrystallization is a predominant factor in the present exchange reaction.

Medical Isotope Production at TRIUMF - from Imaging to Treatment

Science.gov (United States)

Hoehr, C.; Bénard, F.; Buckley, K.; Crawford, J.; Gottberg, A.; Hanemaayer, V.; Kunz, P.; Ladouceur, K.; Radchenko, V.; Ramogida, C.; Robertson, A.; Ruth, T.; Zacchia, N.; Zeisler, S.; Schaffer, P.

TRIUMF has a long history of medical isotope production. For more than 40 years, the Life Sciences Division at TRIUMF has produced isotopes for Positron Emission Tomography (PET) for the local hospitals. Recently, the division has taken on the challenge to expand the facility's isotope repertoire to isotopes for imaging to treatment. At the smallest cyclotron at TRIUMF with energy of 13 MeV, radiometals are being produced in a liquid target which is typically used for PET isotope production. This effort makes radiometals available for early stage research and preclinical trials. At beam energy of 24 MeV, we produce 99mTc from 100Mo with a cyclotron, the most common isotope for Single-Photon-Emission-Computed-Tomography (SPECT) and the most common isotope for nuclear imaging. The use of a cyclotron bypasses the common production route via a nuclear reactor as well as enriched uranium. And finally, at our 500 MeV cyclotron we have demonstrated the production of α emitters useful for targeted alpha therapy. Herein, these efforts are summarized.

Massive mercury target for thallium isotope production on the beam of high energy protons

International Nuclear Information System (INIS)

Novgorodov, A.F.; Kolachkovski, A.; Nguen Kong Chang.

1980-01-01

The yields of thallium radioisotopes in a massive mercury target irradiated with 660 MeV protons have been determined. The constancy of isotopic composition of radiothallium along the whole length (40 cm) of the target has been found. The yields of 200 Tl, 201 Tl and 202 Tl amount to 22.9+-2.8; 3.42+-0.45 and 0.459+-0.61 mCu/mkA h, respectively. It has been shown that the extraction of radioisotopes of thallium and some other elements from large amounts of mercury as well as their subsequent concentration may be carried out fully and relatavely fast when using dilute solutions of acetic acid

Electrical performance of GaN diode as betavoltaic isotope battery energy converter

International Nuclear Information System (INIS)

Wang Guanquan; Yang Yuqing; Liu Yebing; Hu Rui; Li Hao; Zhong Zhengkun; Luo Shunzhong

2013-01-01

Two kinds of GaN PiN diodes were prepared to be the energy converters of betavoltaic batteries, and irradiated by 63 Ni and 3 H radioactive sources. The I sc was 5.4 nA and V oc was 771 mV for 63 Ni source; the I sc was 10.8 nA and V oc was 839 mV for 3 H source. These results show that their V oc are far better than silicon diodes', but their I sc are poor. And there are some differences between the theory values and experiment results. There would be greatly improving space in electrical performance of beta voltaic isotope batteries with GaN diodes as the energy converters, if the dislocation could be reduced in GaN material producing process, the Ohmic contact could be prepared very well and the diodes configuration could be designed more optimizedly in the future. (authors)

First measurements on the core and edge isotope composition using the JET isotope separator neutral particle analyser

International Nuclear Information System (INIS)

Bettella, D; Murari, A; Stamp, M; Testa, D

2003-01-01

Direct measurements of tokamak plasmas isotope composition are in general quite difficult and have therefore been very seldom performed. On the other hand, the importance of this measurement is going to increase, as future experiments will be progressively focused on plasmas approaching reactor conditions. In this paper, we report for the first time encouraging experimental evidence supporting a new method to determine the radial profile of the density ratio n H /(n H + n D ), based on neutral particle analyser (NPA) measurements. The measurements have been performed in JET with the ISotope SEParator (ISEP), a NPA device specifically developed to measure the energy spectra of the three hydrogen isotopes with very high accuracy and low cross-talk. The data presented here have been collected in two different experimental conditions. In the first case, the density ratio has been kept constant during the discharge. The isotope ratio derived from the ISEP has been compared with the results of visible spectroscopy at the edge and with the isotope composition derived from an Alfven eigenmodes active diagnostic (AEAD) system at about half the minor radius for the discharges reported in this paper. A preliminary evaluation of the additional heating effects on the measurements has also been carried out. In the second set of experiments, the isotope composition of deuterium plasmas has been abruptly changed with suitable short blips of hydrogen, in order to assess the capability of the method to study the transport of the hydrogen isotope species. Future developments of the methodology and its applications to the evaluation of hydrogen transport coefficients are also briefly discussed. The results obtained so far motivate further development of the technique, which constitutes one of the few candidate diagnostic approaches viable for ITER

Carbon isotope discrimination as a selection tool for high water use efficiency and high crop yields

International Nuclear Information System (INIS)

Kumarasinghe, K.S.; Kirda, C.; Bowen, G.D.; Zapata, F.; Awonaike, K.O.; Holmgren, E.; Arslan, A.; De Bisbal, E.C.; Mohamed, A.R.A.G.; Montenegro, A.

1996-01-01

Results of back-up research conducted at the FAO/IAEA Agriculture and Biotechnology Laboratory in support of the FAO/IAEA Co-ordinated Research Programme on the Use of Isotope Studies on Increasing and Stabilizing Plant Productivity in Low Phosphate and Semi-arid and Sub-humid Soils of the Tropics and Sub-tropics, are presented here. Neutron probe measurements confirmed the earlier reports of a strong correlation of Δ with grain yield and water use efficiency of wheat. High soil gypsum content and soil salinity, a wide spread problem in soils of arid and semi-arid climatic zones, do not interfere with the association of Δ with crop yields, provided plants are grown in similar soil water status and soil fertility level. Results of a glasshouse experiment using selected cowpea genotypes showed that Δ values measured at flowering stage positively correlated with total dry matter production and percent N 2 derived from atmosphere (%Ndfa), contributing to an earlier report from the laboratory that it may be possible to use Δ values for screening of leguminous crops for high N 2 fixation potential. 13 C isotope discrimination in the leaves of Gliricidia sepium was measured to examine if the technique could be extended to studies with trees. Results of a glasshouse experiment with 18 provenances of Gliricidia sepium showed highly significant correlations of Δ with total dry matter production, water use efficiency and total N accumulated through biological nitrogen fixation. Although the correlation of Δ with water use efficiency and dry matter yield are relatively clear and better understood, the correlation with nitrogen fixation still needs a closer examination under different environmental conditions and with different species. While 13 C isotope discrimination may be a valuable tool for identifying annual crops with high water use efficiency and high yield potential, it may be more attractive for tree species considering the long growth periods taken for trees

Chromatographic speciation of Cr(III)-species, inter-species equilibrium isotope fractionation and improved chemical purification strategies for high-precision isotope analysis

DEFF Research Database (Denmark)

Larsen, Kirsten Kolbjørn; Wielandt, Daniel Kim Peel; Schiller, Martin

2016-01-01

Chromatographic purification of chromium (Cr), which is required for high-precision isotope analysis, is complicated by the presence of multiple Cr-species with different effective charges in the acid digested sample aliquots. The differing ion exchange selectivity and sluggish reaction rates of ...

RFQ beam cooler and buncher for collinear laser spectroscopy of rare isotopes

Science.gov (United States)

Barquest, B. R.; Bollen, G.; Mantica, P. F.; Minamisono, K.; Ringle, R.; Schwarz, S.; Sumithrarachchi, C. S.

2017-09-01

A radiofrequency quadrupole (RFQ) ion beam cooler and buncher has been developed to deliver bunched beams with low transverse emittance, energy spread, and time spread to the BECOLA collinear laser spectroscopy system at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The beam cooler and buncher contains new features which enhance performance, especially for high count rate beams, as well as simplifying construction, maintenance, and operation. The transverse emittance, energy spread, and time spread of the bunched beam, as well as buncher efficiency are reported, showcasing the capabilities of the BECOLA facility to perform collinear laser spectroscopy measurements with bunched rare isotope beams at NSCL and at the future Facility for Rare Isotope Beams (FRIB).

Potassium Stable Isotopic Compositions Measured by High-Resolution MC-ICP-MS

Science.gov (United States)

Morgan, Leah E.; Lloyd, Nicholas S.; Ellam, Robert M.; Simon, Justin I.

2012-01-01

Potassium isotopic (K-41/K-39) compositions are notoriously difficult to measure. TIMS measurements are hindered by variable fractionation patterns throughout individual runs and too few isotopes to apply an internal spike method for instrumental mass fractionation corrections. Internal fractionation corrections via the K-40/K-39 ratio can provide precise values but assume identical K-40/K-39 ratios (e.g. 0.05% (1sigma) in [1]); this is appropriate in some cases (e.g. identifying excess K-41) but not others (e.g., determining mass fractionation effects and metrologically traceable isotopic abundances). SIMS analyses have yielded measurements with 0.25% precisions (1sigma) [2]. ICP-MS analyses are significantly affected by interferences from molecular species such as Ar-38H(+) and Ar-40H(+) and instrument mass bias. Single collector ICP-MS instruments in "cold plasma" mode have yielded uncertainties as low as 2% (1sigma, e.g. [3]). Although these precisions may be acceptable for some concentration determinations, they do not resolve isotopic variation in terrestrial materials. Here we present data from a series of measurements made on the Thermo Scientific NEPTUNE Plus multi-collector ICP-MS that demonstrate the ability to make K-41/K-39 ratio measurements with 0.07% precisions (1sigma). These data, collected on NIST K standards, indicate the potential for MC-ICP-MS measurements to look for K isotopic variations at the sub-permil level. The NEPTUNE Plus can sufficiently resolve 39K and 41K from the interfering 38ArH+ and 40ArH+ peaks in wet cold plasma and high-resolution mode. Measurements were made on small but flat, interference-free, plateaus (ca. 50 ppm by mass width for K-41). Although ICP-MS does not yield accurate K-41/K-39 values due to significant instrumental mass fractionation (ca. 6%), this bias can be sufficiently stable over the time required for several measurements so that relative K-41/K-39 values can be precisely determined via sample

Isotopic dependence of giant multipole resonances

International Nuclear Information System (INIS)

Bar Touv, J.; Moalem, A.; Shlomo, S.

1980-01-01

A procedure is presented which allows the application of linear response theory and the random phase approximation to an open shell. The procedure is applied to Ca isotopes. The general features of giant multipole resonances are found to vary smoothly with the mass. The resonances exhibit more structure in the open lfsub(7/2) shell nuclei. While the energy-weighted dipole sum is practically constant in all isotopes, the isoscalar quadrupole and octupole energy weighted sums increase continuously by approx. 30% from 40 Ca to 48 Ca. (orig.)

A high volume sampling system for isotope determination of volatile halocarbons and hydrocarbons

Directory of Open Access Journals (Sweden)

E. Bahlmann

2011-10-01

Full Text Available The isotopic composition of volatile organic compounds (VOCs can provide valuable information on their sources and fate not deducible from mixing ratios alone. In particular the reported carbon stable isotope ratios of chloromethane and bromomethane from different sources cover a δ¹³C-range of almost 100‰ making isotope ratios a very promising tool for studying the biogeochemistry of these compounds. So far, the determination of the isotopic composition of C₁ and C₂ halocarbons others than chloromethane is hampered by their low mixing ratios.

In order to determine the carbon isotopic composition of C₁ and C₂ halocarbons with mixing ratios as low as 1 pptv (i a field suitable cryogenic high volume sampling system and (ii a chromatographic set up for processing these samples have been developed and validated. The sampling system was tested at two different sampling sites, an urban and a coastal location in Northern Germany. The average δ¹³C-values for bromomethane at the urban site were −42.9 ± 1.1‰ and agreed well with previously published results. But at the coastal site bromomethane was substantially enriched in ¹³C by almost 10‰. Less pronounced differences were observed for chlorodifluoromethane, 1,1,1-trichloroethane and chloromethane. We suggest that these differences are related to the turnover of these compounds in ocean surface waters. Furthermore we report first carbon isotope ratios for iodomethane (−40.4‰ to −79.8‰, bromoform (−13.8‰ to 22.9‰, and other halocarbons.

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

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

Infrastructure for thulium-170 isotope power systems for autonomous underwater vehicle fleets

International Nuclear Information System (INIS)

Walter, C.E.

1991-07-01

The radioisotope thulium-170 is a safe and environmentally benign heat source for providing the high endurance and energy densities needed by advanced power systems for autonomous underwater vehicles (AUV). Thulium Isotope Power (TIP) systems have an endurance of ∼3000 h, and gravimetric and volumetric energy densities of 3 x 10 4 Wh/kg and 3 x 10 8 Wh/m 3 , respectively. These energy densities are more than 200 times higher than those currently provided by Ag-Zn battery technology. In order to capitalize on these performance levels with about one hundred AUVs in continuous use, it will be necessary to establish an infrastructure for isotope production and heat-source refurbishment. The infrastructure cost is not trivial, and studies are needed to determine its optimum configuration. The major component of the projected infrastructure is the nuclear reactor used to produce Tm- 170 by neutron absorption in Tm-169. The reactor design should ideally be optimized for TM-170 production. Using the byproduct ''waste'' heat beneficially would help defray the cost of isotope production. However, generating electric power with the reactor would compromise both the cost of electricity and the isotope production capacity. A coastal location for the reactor would be most convenient from end-use considerations, and the ''waste'' heat could be used to desalinate seawater in water-thirsty states. 13 refs., 6 figs., 2 tabs

β Decay processes of neutron-rich isotopes of sodium and magnesium

International Nuclear Information System (INIS)

Guillemaud, D.

1982-01-01

The γ and n activities from the β decay of Na isotopes up to 34 Na, which are formed in high-energy fragmentation and analysed through mass-spectrometry techniques, are observed as well as those from their Mg descendants. Their intensities Isub(γ) and Isub(β) are measured; some radioactive half lives are determined. Delayed-neutron branching ratios Pn are measured. The existence of 35 Na is for the first time indicated. The position of the first excited 2 + level is taken as an indication of a stronger deformation for that isotope [fr

High-resolution laser spectroscopy of nickel isotopes

CERN Multimedia

This proposal aims to measure the nuclear ground-state spins, moments and mean-square charge radii of $^{56-71}$Ni using collinear laser spectroscopy. This will enable direct measurements of isotopes in the region of shell closure $^{56}$Ni, structural change $^{68}$Ni and monopole migration beyond N = 40. Optical spectroscopy serves as a detailed probe not only of the changing single-particle behaviour, but also for the study of collective properties such as size and shape. Measurements of the most neutron-rich isotopes available at ISOLDE will critically test models which seek to extrapolate the data to the doubly magic region of $^{78}$Ni.

Measuring hydrogen-isotope distribution profiles

International Nuclear Information System (INIS)

Poppe, C.H.

1977-01-01

A new nondestructive technique was developed for measuring the depth distribution of hydrogen isotopes absorbed or implanted near the surface of any material. The method allows real-time study of the inventory and diffusion of hydrogen, deuterium, and tritium. Briefly, the technique involves bombarding the surface with a monoenergetic beam of ions chosen for their ability to react with the hydrogen isotope in question and produce fast neutrons. The energy distribution of the neutrons is a sensitive indicator of the energy of the bombarding particles at the instant of reaction, and hence of the depth of the reaction sites below he surface of the material. A sensitivity of one part per million was obtained for tritium in copper. The technique is applicable to several energy-related materials problems. 5 figures

Operating manual for the High Flux Isotope Reactor. Description of the facility

Energy Technology Data Exchange (ETDEWEB)

None

1965-06-01

This report contains a comprehensive description of the High Flux Isotope Reactor facility. Its primary purpose is to supplement the detailed operating procedures, providing the reactor operators with background information on the various HFIR systems. The detailed operating procedures are presented in another report.

Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer–chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS)

Science.gov (United States)

Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B.; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A.; Schimmelmann, Arndt

2017-01-01

Rationale: Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H2) is responsible for non-quantitative H2 yields and possible hydrogen isotopic fractionation. Our previously introduced, new chromium-based EA-Cr/HTC-IRMS (Elemental Analyzer–Chromium/High-Temperature Conversion Isotope Ratio Mass Spectrometry) technique focused primarily on nitrogen-bearing compounds. Several technical and analytical issues concerning halogen- and sulfur-bearing samples, however, remained unresolved and required further refinement of the reactor systems.

Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media

International Nuclear Information System (INIS)

Popov, L.

2016-01-01

Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials. - Highlights: • The method allows cost-effective determination of U isotopes. • High amounts of environmental samples can be analyzed. • High chemical yields, energy resolution and decontamination factors were achieved. • Uranium isotope concentrations in mineral waters from Bulgaria are presented.

Quantitation of stable isotopic tracers of calcium by fast atom bombardment mass spectrometry

International Nuclear Information System (INIS)

Jiang, X.; Smith, D.L.

1987-01-01

Instrumentation and methodology developed for quantitation of stable isotopic traces in urine are described. Calcium is isolated from urine as the insoluble oxalate salt which is subsequently dissolved in hydrochloric acid. The isotopic content of the acid solution is determined by use of a conventional mass spectrometer equipped with a fast atom bombardment ion source. Calcium ions are desorbed from the sample surface by a beam of high-energy xenon atoms and detected with a high-resolution mass spectrometer. A data acquisition system has been developed to control the mass spectrometer and record the ion signals. Detailed analysis of potential sources of error indicates that the precision of the method is presently limited primarily by an isotope effect that occurs during ion desorption. Results presented here demonstrate that the relative abundances of calcium isotopes in urine can be determined with high precision (coefficient of variation < 0.2%) and that the method is a viable alternative to conventional thermal ionization mass spectrometry. The method is especially attractive because it uses a conventional high-resolution mass spectrometer which is routinely used for analysis of organic substances

Technical developments for an upgrade of the LEBIT Penning trap mass spectrometry facility for rare isotopes

Science.gov (United States)

Redshaw, M.; Barquest, B. R.; Bollen, G.; Bustabad, S. E.; Campbell, C. M.; Ferrer, R.; Gehring, A.; Kwiatkowski, A. A.; Lincoln, D. L.; Morrissey, D. J.; Pang, G. K.; Ringle, R.; Schwarz, S.

2011-07-01

The LEBIT (Low Energy Beam and Ion Trap) facility is the only Penning trap mass spectrometry (PTMS) facility to utilize rare isotopes produced via fast-beam fragmentation. This technique allows access to practically all elements lighter than uranium, and in particular enables the production of isotopes that are not available or that are difficult to obtain at isotope separation on-line facilities. The preparation of the high-energy rare-isotope beam produced by projectile fragmentation for low-energy PTMS experiments is achieved by gas stopping to slow down and thermalize the fast-beam ions, along with an rf quadrupole cooler and buncher and rf quadrupole ion guides to deliver the beam to the Penning trap. During its first phase of operation LEBIT has been very successful, and new developments are now underway to access rare isotopes even farther from stability, which requires dealing with extremely short lifetimes and low production rates. These developments aim at increasing delivery efficiency, minimizing delivery and measurement time, and maximizing use of available beam time. They include an upgrade to the gas-stopping station, active magnetic field monitoring and stabilization by employing a miniature Penning trap as a magnetometer, the use of stored waveform inverse Fourier transform (SWIFT) to most effectively remove unwanted ions, and charge breeding.

Technical developments for an upgrade of the LEBIT Penning trap mass spectrometry facility for rare isotopes

International Nuclear Information System (INIS)

Redshaw, M.; Barquest, B. R.; Bollen, G.; Bustabad, S. E.; Campbell, C. M.; Ferrer, R.; Gehring, A.; Kwiatkowski, A. A.; Lincoln, D. L.; Morrissey, D. J.; Pang, G. K.; Ringle, R.; Schwarz, S.

2011-01-01

The LEBIT (Low Energy Beam and Ion Trap) facility is the only Penning trap mass spectrometry (PTMS) facility to utilize rare isotopes produced via fast-beam fragmentation. This technique allows access to practically all elements lighter than uranium, and in particular enables the production of isotopes that are not available or that are difficult to obtain at isotope separation on-line facilities. The preparation of the high-energy rare-isotope beam produced by projectile fragmentation for low-energy PTMS experiments is achieved by gas stopping to slow down and thermalize the fast-beam ions, along with an rf quadrupole cooler and buncher and rf quadrupole ion guides to deliver the beam to the Penning trap. During its first phase of operation LEBIT has been very successful, and new developments are now underway to access rare isotopes even farther from stability, which requires dealing with extremely short lifetimes and low production rates. These developments aim at increasing delivery efficiency, minimizing delivery and measurement time, and maximizing use of available beam time. They include an upgrade to the gas-stopping station, active magnetic field monitoring and stabilization by employing a miniature Penning trap as a magnetometer, the use of stored waveform inverse Fourier transform (SWIFT) to most effectively remove unwanted ions, and charge breeding.

Nuclear structure of light Ca and heavy Cr isotopes

Energy Technology Data Exchange (ETDEWEB)

Buerger, A.

2007-07-01

In the present thesis, the shell structure in exotic nuclei has been investigated. The focus of the work was on finding new experimental data in neutron-rich Cr and proton-rich Ca isotopes. The investigation of light Ca isotopes concentrated on the nucleus {sup 36}Ca which was produced in a knockout reaction from a radioactive {sup 37}Ca beam. For {sup 36}Ca, the excitation energy of the first 2{sup +} state has been measured for the first time. Furthermore, momentum distributions were analyzed using a Monte-Carlo simulation of the knockout reaction. This analysis yielded the contributions of neutrons from individual orbitals to the total knockout cross section. In principle, these may be used to calculate spectroscopic factors, but such a calculation is hampered by difficulties of present knockout-reaction models in predicting precise single-particle cross sections. The measured branching ratio to the ground and excited states, on the other hand, is close to the predicted value. A remaining difference might be due to emission of protons which cannot be detected with the present experimental setup. Both the branching ratio and the large excitation energy are compatible with a large N=16 gap in {sup 36}Ca that leads to relatively pure configurations both in the ground state and the excited 2{sup +} state. As a by-product of the experiment, two excitation energies in the T=2 nuclei {sup 32}Ar and {sup 28}S have been confirmed, and two {gamma}-ray transitions have been observed for the first time in {sup 37}Ca. While the mirror energy differences in the T=2 pairs {sup 36}Ca-{sup 36}S, {sup 32}Ar-{sup 32}Si, and {sup 28}S-{sup 28}Mg can be reproduced in shell model calculations using a modified USD interaction, these modifications are not sufficient to explain the mirror energy differences for the pair {sup 37}Ca-{sup 37}Cl. In the heavy Cr isotopes, new experimental evidence for a sub-shell closure at N=32 was found in a measurement of B(E2) values using high-energy

Climatic signals in multiple highly resolved stable isotope records from Greenland

DEFF Research Database (Denmark)

Vinther, Bo Møllesøe; Dahl-Jensen, Dorthe; Johnsen, Sigfus Johann

2010-01-01

are found to correspond better with winter stable isotope data than with summer or annual average stable isotope data it is suggested that a strong local Greenland temperature signal can be extracted from the winter stable isotope data even on centennial to millennial time scales. Udgivelsesdato: Feb....

HTSSIP: An R package for analysis of high throughput sequencing data from nucleic acid stable isotope probing (SIP experiments.

Directory of Open Access Journals (Sweden)

Nicholas D Youngblut

Full Text Available Combining high throughput sequencing with stable isotope probing (HTS-SIP is a powerful method for mapping in situ metabolic processes to thousands of microbial taxa. However, accurately mapping metabolic processes to taxa is complex and challenging. Multiple HTS-SIP data analysis methods have been developed, including high-resolution stable isotope probing (HR-SIP, multi-window high-resolution stable isotope probing (MW-HR-SIP, quantitative stable isotope probing (qSIP, and ΔBD. Currently, there is no publicly available software designed specifically for analyzing HTS-SIP data. To address this shortfall, we have developed the HTSSIP R package, an open-source, cross-platform toolset for conducting HTS-SIP analyses in a straightforward and easily reproducible manner. The HTSSIP package, along with full documentation and examples, is available from CRAN at https://cran.r-project.org/web/packages/HTSSIP/index.html and Github at https://github.com/buckleylab/HTSSIP.

Description of magnetic moments of long isotopic chains within the FFS theory

Energy Technology Data Exchange (ETDEWEB)

Borzov, I.N. [IPPE, Obninsk (Russian Federation); Saperstein, E.E.; Tolokonnikov, S.V. [Kurchatov Institute, Moscow (Russian Federation); Neyens, G.; Severijns, N. [Katholieke Universiteit Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium)

2010-08-15

Dipole magnetic moments of several long isotopic chains are analyzed within the self-consistent finite Fermi system theory with exact account for the pairing and quasiparticle continuum. The momentum dependence of the spin-isospin Landau-Migdal amplitude g' is taken into account. This dependence was introduced previously to describe high-energy electron magnetic scattering. New moment data for nuclei far from the {beta} -stability valley are included in the analysis. For a number of semi-magic isotopes of the tin and lead chains a good description of the data is obtained, with an accuracy of 0.1- 0.2{mu}{sub N}. A chain of non-magic isotopes of copper is also analyzed in detail. (orig.)

High-efficiency technology for lithium isotope separation using an ionic-liquid impregnated organic membrane

International Nuclear Information System (INIS)

Hoshino, Tsuyoshi; Terai, Takayuki

2011-01-01

The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ( 6 Li) in tritium breeding materials. New lithium isotope separation technique using ionic-liquid impregnated organic membranes (Ionic-Liquid-i-OMs) have been developed. Lithium ions are able to move by electrodialysis through certain Ionic-Liquid-i-OMs between the cathode and the anode in lithium solutions. In this report, the effects of protection cover and membrane thickness on the durability of membrane and the efficiency of isotope separation were evaluated. In order to improve the durability of the Ionic-Liquid-i-OM, we developed highly-durable Ionic-Liquid-i-OM. Both surfaces of the Ionic-Liquid-i-OM were covered by a nafion 324 overcoat or a cation exchange membrane (SELEMION TM CMD) to prevent the outflow of the ionic liquid. It was observed that the durability of the Ionic-Liquid-i-OM was improved by a nafion 324 overcoat. On the other hand, the organic membrane selected was 1, 2 or 3 mm highly-porous Teflon film, in order to efficiently impregnate the ionic liquid. The 6 Li isotope separation factor by electrodialysis using highly-porous Teflon film of 3 mm thickness was larger than using that of 1 or 2 mm thickness.

High fidelity nuclear energy system optimization towards an environmentally benign, sustainable, and secure energy source

International Nuclear Information System (INIS)

Tsvetkov, Pavel Valeryevich; Rodriguez, Salvador B.; Ames, David E. II; Rochau, Gary Eugene

2009-01-01

-models for overall analysis of the system. It also provides control over key user input parameters and the ability to effectively consolidate vital output results for uncertainty/sensitivity analysis and optimization procedures. The preliminary analysis has shown promising advanced fuel cycle scenarios that include Pressure Water Reactors Pressurized Water Reactors (PWRs), Very High Temperature Reactors (VHTRs) and dedicated HEST waste incineration facilities. If deployed, these scenarios may substantially reduce nuclear waste inventories approaching environmentally benign nuclear energy system characteristics. Additionally, a spent fuel database of the isotopic compositions for multiple design and control parameters has been created for the VHTR-HEST input fuel streams. Computational approaches, analysis metrics, and benchmark strategies have been established for future detailed studies.

Isotopic Exchange in Porous and Dense Magnesium Borohydride.

Science.gov (United States)

Zavorotynska, Olena; Deledda, Stefano; Li, Guanqiao; Matsuo, Motoaki; Orimo, Shin-ichi; Hauback, Bjørn C

2015-09-01

Magnesium borohydride (Mg(BH4)2) is one of the most promising complex hydrides presently studied for energy-related applications. Many of its properties depend on the stability of the BH4(-) anion. The BH4(-) stability was investigated with respect to H→D exchange. In situ Raman measurements on high-surface-area porous Mg(BH4 )2 in 0.3 MPa D2 have shown that the isotopic exchange at appreciable rates occurs already at 373 K. This is the lowest exchange temperature observed in stable borohydrides. Gas-solid isotopic exchange follows the BH4(-) +D˙ →BH3D(-) +H˙ mechanism at least at the initial reaction steps. Ex situ deuteration of porous Mg(BH4)2 and its dense-phase polymorph indicates that the intrinsic porosity of the hydride is the key behind the high isotopic exchange rates. It implies that the solid-state H(D) diffusion is considerably slower than the gas-solid H→D exchange reaction at the surface and it is a rate-limiting steps for hydrogen desorption and absorption in Mg(BH4)2. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel wave/ion beam interaction approach to isotope separation

International Nuclear Information System (INIS)

Post, R.F.; Lowder, R.S.; Schwager, L.A.; Barr, W.L.; Warner, B.E.

1993-02-01

Numerical simulations and experimental studies have been made related to the possibility of employing an externally imposed electrostatic potential wave to separate isotopes. This wave/ion interaction is a sensitive function of the wave/ion difference velocity and for the appropriate wave amplitude and wave speed, a lighter faster isotope will be reflected by the wave to a higher energy while leaving heavier, slower isotopes virtually undisturbed in energy -- allowing subsequent ion separation by simple energy discrimination. In these experiments, a set of some 200 individual, electrodes, which surrounded a microamp beam of neon ions, was used to generate the wave. Measurements of the wave amplitudes needed for ion reflection and measurements of the final energies of those reflected ions are consistent with values expected from simple kinetic arguments and with the more detailed results of numeric simulations

High-resolution studies of tropolone in the S0 and S1 electronic states: isotope driven dynamics in the zero-point energy levels.

Science.gov (United States)

Keske, John C; Lin, Wei; Pringle, Wallace C; Novick, Stewart E; Blake, Thomas A; Plusquellic, David F

2006-02-21

Rotationally resolved microwave (MW) and ultraviolet (UV) spectra of jet-cooled tropolone have been obtained in S(0) and S(1) electronic states using Fourier-transform microwave and UV-laser/molecular-beam spectrometers. In the ground electronic state, the MW spectra of all heavy-atom isotopomers including one (18)O and four (13)C isotopomers were observed in natural abundance. The OD isotopomer was obtained from isotopically enriched samples. The two lowest tunneling states of each isotopomer except (18)O have been assigned. The observed inversion splitting for the OD isotopomer is 1523.227(5) MHz. For the asymmetric (13)C structures, the magnitudes of tunneling-rotation interactions are found to diminish with decreasing distance between the heavy atom and the tunneling proton. In the limit of closest approach, the 0(+) state of (18)O was well fitted to an asymmetric rotor Hamiltonian, reflecting significant changes in the tautomerization dynamics. Comparisons of the substituted atom coordinates with theoretical predictions at the MP2/aug-cc-pVTZ level of theory suggest the localized 0(+) and 0(-) wave functions of the heavier isotopes favor the C-OH and C=O forms of tropolone, respectively. The only exception occurs for the (13)C-OH and (13)C[Double Bond]O structures which correlate to the 0(-) and 0(+) states, respectively. These preferences reflect kinetic isotope effects as quantitatively verified by the calculated zero-point energy differences between members of the asymmetric atom pairs. From rotationally resolved data of the 0(+) <--0(+) and 0(-) <--0(-) bands in S(1), line-shape fits have yielded Lorentzian linewidths that differ by 12.2(16) MHz over the 19.88(4) cm(-1) interval in S(1). The fluorescence decay rates together with previously reported quantum yield data give nonradiative decay rates of 7.7(5) x 10(8) and 8.5(5) x 10(8) s(-1) for the 0(+) and 0(-) levels of the S(1) state of tropolone.

External event Probabilistic Risk Assessment for the High Flux Isotope Reactor (HFIR)

International Nuclear Information System (INIS)

Flanagan, G.F.; Johnson, D.H.; Buttemer, D.; Perla, H.F.; Chien, S.H.

1989-01-01

The High Flux Isotope Reactor (HFIR) is a high performance isotope production and research reactor which has been in operation at Oak Ridge National Laboratory (ORNL) since 1965. In late 1986 the reactor was shut down as a result of discovery of unexpected neutron embrittlement of the reactor vessel. In January of 1988 a level 1 Probabilistic Risk Assessment (PRA) (excluding external events) was published as part of the response to the many reviews that followed the shutdown and for use by ORNL to prioritize action items intended to upgrade the safety of the reactor. A conservative estimate of the core damage frequency initiated by internal events for HFIR was 3.11 x 10 -4 . In June 1989 a draft external events initiated PRA was published. The dominant contributions from external events came from seismic, wind, and fires. The overall external event contribution to core damage frequency is about 50% of the internal event initiated contribution and is dominated by seismic events

Isotopic effect giant resonances

International Nuclear Information System (INIS)

Buenerd, M.; Lebrun, D.; Martin, P.; Perrin, G.; Saintignon, P. de; Chauvin, J.; Duhamel, G.

1981-10-01

The systematics of the excitation energy of the giant dipole, monopole, and quadrupole resonances are shown to exhibit an isotopic effect. For a given element, the excitation energy of the transition decreases faster with the increasing neutron number than the empirical laws fitting the overall data. This effect is discussed in terms of the available models

Extraction of gadolinium from high flux isotope reactor control plates

International Nuclear Information System (INIS)

Kohring, M.W.

1987-04-01

Gadolinium-153 is an important radioisotope used in the diagnosis of various bone disorders. Recent medical and technical developments in the detection and cure of osteoporosis, a bone disease affecting an estimated 50 million people, have greatly increased the demand for this isotope. The Oak Ridge National Laboratory (ORNL) has produced 153 Gd since 1980 primarily through the irradiation of a natural europium-oxide powder followed by the chemical separation of the gadolinium fraction from the europium material. Due to the higher demand for 153 Gd, an alternative production method to supplement this process has been investigated. This process involves the extraction of gadolinium from the europium-bearing region of highly radioactive, spent control plates used at the High Flux Isotope Reactor (HFIR) with a subsequent re-irradiation of the extracted material for the production of the 153 Gd. Based on the results of experimental and calculational analyses, up to 25 grams of valuable gadolinium (≥60% enriched in 152 Gd) resides in the europium-bearing region of the HFIR control components of which 70% is recoverable. At a specific activity yield of 40 curies of 153 Gd for each gram of gadolinium re-irradiated, 700 one-curie sources can be produced from each control plate assayed

Design of LSDS for Isotopic Fissile Assay in Spent Fuel

International Nuclear Information System (INIS)

Lee, Yongdeok; Park, Changje; Kim, Hodong; Song, Kee Chan

2013-01-01

A future nuclear energy system is being developed at Korea Atomic Energy Research Institute (KAERI), the system involves a Sodium Fast Reactor (SFR) linked with the pyro-process. The pyro-process produces a source material to fabricate a SFR fuel rod. Therefore, an isotopic fissile content assay is very important for fuel rod safety and SFR economics. A new technology for an analysis of isotopic fissile content has been proposed using a lead slowing down spectrometer (LSDS). The new technology has several features for a fissile analysis from spent fuel: direct isotopic fissile assay, no background interference, and no requirement from burnup history information. Several calculations were done on the designed spectrometer geometry: detection sensitivity, neutron energy spectrum analysis, neutron fission characteristics, self shielding analysis, and neutron production mechanism. The spectrum was well organized even at low neutron energy and the threshold fission chamber was a proper choice to get prompt fast fission neutrons. The characteristic fission signature was obtained in slowing down neutron energy from each fissile isotope. Another application of LSDS is for an optimum design of the spent fuel storage, maximization of the burnup credit and provision of the burnup code correction factor. Additionally, an isotopic fissile content assay will contribute to an increase in transparency and credibility for the utilization of spent fuel nuclear material, as internationally demanded

DESIGN OF LSDS FOR ISOTOPIC FISSILE ASSAY IN SPENT FUEL

Directory of Open Access Journals (Sweden)

YONGDEOK LEE

2013-12-01

Full Text Available A future nuclear energy system is being developed at Korea Atomic Energy Research Institute (KAERI, the system involves a Sodium Fast Reactor (SFR linked with the pyro-process. The pyro-process produces a source material to fabricate a SFR fuel rod. Therefore, an isotopic fissile content assay is very important for fuel rod safety and SFR economics. A new technology for an analysis of isotopic fissile content has been proposed using a lead slowing down spectrometer (LSDS. The new technology has several features for a fissile analysis from spent fuel: direct isotopic fissile assay, no background interference, and no requirement from burnup history information. Several calculations were done on the designed spectrometer geometry: detection sensitivity, neutron energy spectrum analysis, neutron fission characteristics, self shielding analysis, and neutron production mechanism. The spectrum was well organized even at low neutron energy and the threshold fission chamber was a proper choice to get prompt fast fission neutrons. The characteristic fission signature was obtained in slowing down neutron energy from each fissile isotope. Another application of LSDS is for an optimum design of the spent fuel storage, maximization of the burnup credit and provision of the burnup code correction factor. Additionally, an isotopic fissile content assay will contribute to an increase in transparency and credibility for the utilization of spent fuel nuclear material, as internationally demanded.

Isotopic scaling of transport in deuterium-tritium plasmas

International Nuclear Information System (INIS)

Scott, S.D.; Murakami, M.; Adler, H.; Chang, Z.; Duong, H.; Grisham, L.R.; Fredrickson, E.D.; Grek, B.; Hawryluk, R.J.; Hill, K.W.; Hosea, J.; Jassby, D.L.; Johnson, D.W.; Johnson, L.C.; Loughlin, M.J.; Mansfield, D.K.; McGuire, K.M.; Meade, D.M.; Mikkelsen, D.M.; Murphy, J.; Park, H.K.; Ramsey, A.T.; Schivell, J.; Skinner, C.H.; Strachan, J.D.; Synakowski, E.J.; Taylor, G.; Thompson, M.E.; Wieland, R.; Zarnstorff, M.C.

1995-01-01

Both global and thermal energy confinement improve in high-temperature supershot plasmas in the Tokamak Fusion Test Reactor (TFTR) when deuterium beam heating is partially or wholly replaced by tritium beam heating. For the same heating power, the tritium-rich plasmas obtain up to 22% higher total energy, 30% higher thermal ion energy, and 20-25% higher central ion temperature. Kinetic analysis of the temperature and density profiles indicates a favorable isotopic scaling of ion heat transport and electron particle transport, with τ Ei (a/2) ∝ left angle A right angle 0.7-0.8 and τ pe (a) ∝ left angle A right angle 0.8 . (orig.)

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)

Thermal Rate Coefficients and Kinetic Isotope Effects for the Reaction OH + CH4 → H2O + CH3 on an ab Initio-Based Potential Energy Surface.

Science.gov (United States)

Li, Jun; Guo, Hua

2018-03-15

Thermal rate coefficients for the title reaction and its various isotopologues are computed using a tunneling-corrected transition-state theory on a global potential energy surface recently developed by fitting a large number of high-level ab initio points. The calculated rate coefficients are found to agree well with the measured ones in a wide temperature range, validating the accuracy of the potential energy surface. Strong non-Arrhenius effects are found at low temperatures. In addition, the calculations reproduced the primary and secondary kinetic isotope effects. These results confirm the strong influence of tunneling to this heavy-light-heavy hydrogen abstraction reaction.

Pressurizer pump reliability analysis high flux isotope reactor

International Nuclear Information System (INIS)

Merryman, L.; Christie, B.

1993-01-01

During a prolonged outage from November 1986 to May 1990, numerous changes were made at the High Flux Isotope Reactor (HFIR). Some of these changes involved the pressurizer pumps. An analysis was performed to calculate the impact of these changes on the pressurizer system availability. The analysis showed that the availability of the pressurizer system dropped from essentially 100% to approximately 96%. The primary reason for the decrease in availability comes because off-site power grid disturbances sometimes result in a reactor trip with the present pressurizer pump configuration. Changes are being made to the present pressurizer pump configuration to regain some of the lost availability

Alternative applications of atomic vapor laser isotope separation technology

International Nuclear Information System (INIS)

1991-01-01

This report was commissioned by the Secretary of Energy. It summarizes the main features of atomic vapor laser isotope separation (AVLIS) technology and subsystems; evaluates applications, beyond those of uranium enrichment, suggested by Lawrence Livermore National Laboratory (LLNL) and a wide range of US industries and individuals; recommends further work on several applications; recommends the provision of facilities for evaluating potential new applications; and recommends the full involvement of end users from the very beginning in the development of any application. Specifically excluded from this report is an evaluation of the main AVLIS missions, uranium enrichment and purification of plutonium for weapons. In evaluating many of the alternative applications, it became clear that industry should play a greater and earlier role in the definition and development of technologies with the Department of Energy (DOE) if the nation is to derive significant commercial benefit. Applications of AVLIS to the separation of alternate (nonuranium) isotopes were considered. The use of 157 Gd as burnable poison in the nuclear fuel cycle, the use 12 C for isotopically pure diamond, and the use of plutonium isotopes for several nonweapons applications are examples of commercially useful products that might be produced at a cost less than the product value. Separations of other isotopes such as the elemental constituents of semiconductors were suggested; it is recommended that proposed applications be tested by using existing supplies to establish their value before more efficient enrichment processes are developed. Some applications are clear, but their production costs are too high, the window of opportunity in the market has passed, or societal constraints (e.g., on reprocessing of reactor fuel) discourage implementation

Performance characteristics of conventional X-ray generator isotope source and high energy accelerator in rocket motor evaluation

International Nuclear Information System (INIS)

Viswanathan, K.; Rao, K.V.; Subbalah, C.; Uttam, M.C.

1985-01-01

Final qualification of solid rocket motors and other related components in the Indian Space Programme is carried out using radiographic sources of different energies. The necessity to have different sources of varying energies arises from the fact that the components in the space programme vary from small fastners to gigantic solid rocket motors. In order to achieve the best radiographic quality with the optimised exposure time different X-ray sources are used. To have 100% coverage and to reduce the inspection time, a Real Time Radiography for the high energy LINAC is also planned

Component and system simulation models for High Flux Isotope Reactor

International Nuclear Information System (INIS)

Sozer, A.

1989-08-01

Component models for the High Flux Isotope Reactor (HFIR) have been developed. The models are HFIR core, heat exchangers, pressurizer pumps, circulation pumps, letdown valves, primary head tank, generic transport delay (pipes), system pressure, loop pressure-flow balance, and decay heat. The models were written in FORTRAN and can be run on different computers, including IBM PCs, as they do not use any specific simulation languages such as ACSL or CSMP. 14 refs., 13 figs

Method of isotope separation

Energy Technology Data Exchange (ETDEWEB)

Lyon, R K

1975-05-22

Isotopes of a gaseous compound can be separated by multi-infrared photoabsorption which follows a selective dissociation of the excited molecules by single photon absorption of photons of visible or UV radiation. The process involves three steps. Firstly, the molecules to be separated are irradiated with a high-energy IR laser, whereby the molecules of the compound containing the lighter isotopes are preferably excited. They are then irradiated by a second laser with UV or visible light whose frequency of radiation brings the excited molecules into a form in which they can be separated from the non-excited molecules. The third step is the reformation of the substances according to known methods. A power density of at least 10/sup 4/ watt/cm/sup 2/ per torr gas pressure with an irradiation time of 10/sup -10/ to 5 x 10/sup -5/ seconds in the presence of a second gas with at least 5 times higher partial pressure is necessary for the IR radiation. The method may be used for UF/sub 6/ for which an example is given here.

PLUTON, Isotope Generation and Depletion in Highly Irradiated LWR Fuel Rods

International Nuclear Information System (INIS)

Lemehov, Sergei; Motoe, Suzuki

2003-01-01

1 - Description of program or function: The PLUTON-PC is a three-group neutronic code analyzing, as functions of time and burnup, the change of radial profiles, together with average values, of power density, burnup, concentration of trans-uranium elements, plutonium buildup, depletion of fissile elements, and fission product generation in water reactor fuel rod with standard UO 2 , UO 2 -Gd 2 O 3 , inhomogeneous MOX, and UO 2 -ThO 2 . The PLUTON-PC code, which has been designed to be run on Windows PC, has adopted a theoretical shape function of neutron attenuation in pellet, which enables users to perform a very fast and accurate calculation easily. The code includes the irradiation conditions of the Halden Reactor which gives verification data for the code. Verification has been performed up to 83 GWd/tU, and a satisfactory agreement has been obtained. 2 - Methods: Based upon cumulative yields, the PLUTON-PC code calculates as a function of radial position and local burnup concentrations of fission products, macroscopic scattering cross-sections and self-shielding effect which is important for standard fuel (for Pu-242 mainly) and more importantly for homogeneous and inhomogeneous MOX fuel because of higher concentrations of fissile and fertile isotopes of plutonium. The code results in burnup dependent fission rate density profiles throughout the in-reactor irradiation of LWR fuel rods. The isotopes included in calculations have been extended to cover all trans-uranium groups (plutonium plus higher actinides) of fissile and fertile isotopes. Self-shielding problem and scattering effects have been revised and solved for all isotopes in the calculations for adequacy at high burnup, different irradiation conditions and cladding materials

Quantitative analysis of 39 polybrominated diphenyl ethers by isotope dilution GC/low-resolution MS.

Science.gov (United States)

Ackerman, Luke K; Wilson, Glenn R; Simonich, Staci L

2005-04-01

A GC/low-resolution MS method for the quantitative isotope dilution analysis of 39 mono- to heptabrominated diphenyl ethers was developed. The effects of two different ionization sources, electron impact (EI) and electron capture negative ionization (ECNI), and the effects of their parameters on production of high-mass fragment ions [M - xH - yBr](-) specific to PBDEs were investigated. Electron energy, emission current, source temperature, ECNI system pressure, and choice of ECNI reagent gases were optimized. Previously unidentified enhancement of PBDE high-mass fragment ion [M - xH - yBr](-) abundance was achieved. Electron energy had the largest impact on PBDE high-mass fragment ion abundance for both the ECNI and EI sources. By monitoring high-mass fragment ions of PBDEs under optimized ECNI source conditions, quantitative isotope dilution analysis of 39 PBDEs was conducted using nine (13)C(12) labeled PBDEs on a low-resolution MS with low picogram to femtogram instrument detection limits.

Krypton isotope analysis using near-resonant stimulated Raman spectroscopy

International Nuclear Information System (INIS)

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

1994-12-01

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

Evaluation of medical isotope production with the accelerator production of tritium (APT) facility

International Nuclear Information System (INIS)

Benjamin, R.W.; Frey, G.D.; McLean, D.C., Jr; Spicer, K.M.; Davis, S.E.; Baron, S.; Frysinger, J.R.; Blanpied, G.; Adcock, D.

1997-01-01

The accelerator production of tritium (APT) facility, with its high beam current and high beam energy, would be an ideal supplier of radioisotopes for medical research, imaging, and therapy. By-product radioisotopes will be produced in the APT window and target cooling systems and in the tungsten target through spallation, neutron, and proton interactions. High intensity proton fluxes are potentially available at three different energies for the production of proton- rich radioisotopes. Isotope production targets can be inserted into the blanket for production of neutron-rich isotopes. Currently, the major production sources of radioisotopes are either aging or abroad, or both. The use of radionuclides in nuclear medicine is growing and changing, both in terms of the number of nuclear medicine procedures being performed and in the rapidly expanding range of procedures and radioisotopes used. A large and varied demand is forecast, and the APT would be an ideal facility to satisfy that demand

High-Voltage Power Supply System for Laser Isotope Separation

Energy Technology Data Exchange (ETDEWEB)

Ketaily, E.C.; Buckner, R.P.; Uhrik, R.L.

1979-06-26

This report presents several concepts for Laser High-Voltage Power Supply (HVPS) Systems for a Laser Isotope Separation facility. Selection of equipments and their arrangement into operational systems is based on proven designs and on application concepts now being developed. This report has identified a number of alternative system arrangements and has provided preliminary cost estimates for each. The report includes a recommendation for follow-on studies that will further define the optimum Laser HVPS Systems. Brief descriptions are given of Modulator/Regulator circuit trade-offs, system control interfaces, and their impact on costs.

High-Voltage Power Supply System for Laser Isotope Separation

International Nuclear Information System (INIS)

Ketaily, E.C.; Buckner, R.P.; Uhrik, R.L.

1979-01-01

This report presents several concepts for Laser High-Voltage Power Supply (HVPS) Systems for a Laser Isotope Separation facility. Selection of equipments and their arrangement into operational systems is based on proven designs and on application concepts now being developed. This report has identified a number of alternative system arrangements and has provided preliminary cost estimates for each. The report includes a recommendation for follow-on studies that will further define the optimum Laser HVPS Systems. Brief descriptions are given of Modulator/Regulator circuit trade-offs, system control interfaces, and their impact on costs

High-spin level structure and Ground-state phase transition in the odd-mass 103-109Rh isotopes in the framework of exactly solvable sdg interacting boson-fermion model

Science.gov (United States)

Ghapanvari, M.; Ghorashi, A. H.; Ranjbar, Z.; Jafarizadeh, M. A.

2018-03-01

In this article, the negative-parity states in the odd-mass 103 - 109Rh isotopes in terms of the sd and sdg interacting-boson fermion models were studied. The transitional interacting boson-fermion model Hamiltonians in sd and sdg-IBFM versions based on affine SU (1 , 1) Lie Algebra were employed to describe the evolution from the spherical to deformed gamma unstable shapes along with the chain of Rh isotopes. In this method, sdg-IBFM Hamiltonian, which is a three level pairing Hamiltonian was determined easily via the exactly solvable method. Some observables of the shape phase transitions such as energy levels, the two neutron separation energies, signature splitting of the γ-vibrational band, the α-decay and double β--decay energies were calculated and examined for these isotopes. The present calculation correctly reproduces the spherical to gamma-soft phase transition in the Rh isotopes. Some comparisons were made with sd-IBFM.

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

Online stable carbon isotope ratio measurement in formic acid, acetic acid, methanol and ethanol in water by high performance liquid chromatography-isotope ratio mass spectrometry

International Nuclear Information System (INIS)

Tagami, Keiko; Uchida, Shigeo

2008-01-01

A suitable analysis condition was determined for high performance liquid chromatography-isotope ratio mass spectrometry (HPLC-IRMS) while making sequential measurements of stable carbon isotope ratios of δ 13 C in formic acid, acetic acid, methanol and ethanol dissolved in water. For this online column separation method, organic reagents are not applicable due to carbon contamination; thus, water and KH 2 PO 4 at low concentrations were tested as mobile phase in combination with a HyPURITY AQUASTAR TM column. Formic acid, acetic acid, methanol and ethanol were separated when 2 mM KH 2 PO 4 aqueous solution was used. Under the determined analysis condition for HPLC-IRMS, carbon concentrations could be measured quantitatively as well as carbon isotope ratio when carbon concentration was higher than 0.4 mM L for each chemical

Isotope separation by photodissociation of Van der Wall's molecules

International Nuclear Information System (INIS)

Lee, Y.T.

1977-01-01

A method of separating isotopes based on the dissociation of a Van der Waal's complex is described. A beam of molecules of a Van der Waal's complex containing, as one partner of the complex, a molecular species in which an element is present in a plurality of isotopes is subjected to radiation from a source tuned to a frequency which will selectively excite vibrational motion by a vibrational transition or through electronic transition of those complexed molecules of the molecular species which contain a desired isotope. Since the Van der Waal's binding energy is much smaller than the excitational energy of vibrational motion, the thus excited Van der Waal's complex dissociate into molecular components enriched in the desired isotope. The recoil velocity associated with vibrational to translational and rotational relaxation will send the separated molecules away from the beam whereupon the product enriched in the desired isotope can be separated from the constituents of the beam

Evolution of single-particle structure of silicon isotopes

Science.gov (United States)

Bespalova, O. V.; Fedorov, N. A.; Klimochkina, A. A.; Markova, M. L.; Spasskaya, T. I.; Tretyakova, T. Yu.

2018-01-01

New data on proton and neutron single-particle energies E_{nlj} of Si isotopes with neutron number N from 12 to 28 as well as occupation probabilities N_{nlj} of single-particle states of stable isotopes 28, 30Si near the Fermi energy were obtained by the joint evaluation of the stripping and pick-up reaction data and excited state decay schemes of neighboring nuclei. The evaluated data indicate the following features of single-particle structure evolution: persistence of Z = 14 subshell closure with N increase, the new magicity of the number N = 16, and the conservation of the magic properties of the number N = 20 in Si isotopic chain. The features were described by the dispersive optical model. The calculation also predicts the weakening of N = 28 shell closure and demonstrates evolution of a bubble-like structure of the proton density distributions in neutron-rich Si isotopes.

Precision experiments with rare isotopes with LEBIT at MSU

Energy Technology Data Exchange (ETDEWEB)

Schury, P.; Bollen, G.; Ringle, R.; Sun, T. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Michigan State University, Department of Physics and Astronomy, East Lansing, MI (United States); Davies, D.A.; Morrissey, D.J. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States); Michigan State University, Department of Chemistry, East Lansing, MI (United States); Doemer, A.; Prinke, A. [Michigan State University, Department of Physics and Astronomy, East Lansing, MI (United States); Lawton, D.; Ottarson, J.; Schwarz, S.; Weissman, L. [National Superconducting Cyclotron Laboratory, East Lansing, MI (United States)

2005-09-01

The Low-Energy Beam and Ion Trap facility LEBIT at the NSCL is in the final phase of commissioning. Gas stopping of fast fragment beams and modern ion manipulation techniques are used to provide beams for high-precision mass measurements and other experiments. The status of the facility and the result of first test mass measurements on stable krypton isotopes are presented. (orig.)

NSDD LBNL Isotopes Project Collaboration Report

Energy Technology Data Exchange (ETDEWEB)

Firestone, R. B. [Isotopes Project, Lawrence Berkeley National Laboratory, Berkeley CA (United States)

2013-08-15

The Isotopes Project group currently consists of five scientists and a postdoctoral student. It also leads the Evaluated Gamma-ray Activation File (EGAF) collaboration consisting of over 20 scientists at ten universities and laboratories. The group is responsible for the evaluation of mass chains in the region 21-30. EGAF evaluations: The Isotope Project's primary effort is to measure and evaluate neutron capture {gamma}-ray cross section data for all stable and selected radioactive isotopes. These data include prompt and delayed {gamma}-ray cross sections, {delta}{sub {gamma}}, total thermal radiative neutron cross sections, {delta}{sub 0}, and neutron separation energies, S{sub n}. The first EGAF elemental {gamma}-ray cross section library was published as the result of an IAEA CRP and the neutron separation energies were supplied to the Atomic Mass Evaluation project for inclusion in their most recent evaluation. EGAF is being updated with new experiments on enriched isotopes using the Budapest and Munich FRM II guided neutron beam facilities. New measurements have been performed on the isotopes {sup 151,153}Eu, {sup 155,157}Gd, {sup 180,182,183,184,186}W, {sup 237}Np, {sup 240}Pu, and {sup 241}Am. Additional measurements have been approved for 2013 on {sup 70,72,73,74,76}Ge, {sup 90,91,92,94,96}Zr, and {sup 238}U.

Marginal-Fermi-liquid theory and the isotope effect

International Nuclear Information System (INIS)

Nicol, E.J.; Carbotte, J.P.

1991-01-01

In the marginal-Fermi-liquid model, the coupling between two electrons is via charge (attractive) and spin (repulsive) fluctuations, and so it does not exhibit an isotope effect. To include this effect, an additional phonon contribution must be introduced. Using the case of YBa 2 Cu 3 O 7 , for illustrative purposes, with a total isotope effect coefficient of β tot congruent 0.05 at a T c of 90 K, we find that the implied electron-phonon mass renormalization is very small for coupling to high-energy phonons but increases rapidly with decreasing phonon frequency or an increasing amount of spin fluctuations. Finally, we examine how β increases with decreasing T c when charge fluctuations are reduced or spin fluctuations augmented

Neutron cross section evaluations of europium isotopes in 1 keV - 30 MeV energy range. Format - validation - comparison; Evaluation de sections efficaces pour des neutrons incidents sur des isotopes d'europium aux energies 1 keV - 30 MeV. Format - validation - comparaison

Energy Technology Data Exchange (ETDEWEB)

Dossantos-Uzarralde, P.; Le Luel, C.; Bauge, E. [CEA Bruyeres le Chatel, 91 (France). Dept. de Physique Theorique et Appliquee

2004-07-01

This paper presents neutron cross section evaluations of Europium isotopes. The cross sections are evaluated in 1 keV - 30 MeV energy range for the isotopes {sup 146}Eu, {sup 147}Eu, {sup 148}Eu, {sup 149}Eu, {sup 150}Eu, {sup 151}Eu, {sup 152}Eu, {sup 153}Eu, {sup 154}Eu in their ground state. This evaluation includes cross section productions of the long life isomeric states. Special attention is put on the options used for the description of the files written in ENDF-6 format. The final issue is a proposal of a new breed of ENDF-6 formatted neutron activation file. (authors)

Report of the ANS Project Feasibility Workshop for a High Flux Isotope Reactor-Center for Neutron Research Facility

International Nuclear Information System (INIS)

Peretz, F.J.; Booth, R.S.

1995-07-01

The Advanced Neutron Source (ANS) Conceptual Design Report (CDR) and its subsequent updates provided definitive design, cost, and schedule estimates for the entire ANS Project. A recent update to this estimate of the total project cost for this facility was $2.9 billion, as specified in the FY 1996 Congressional data sheet, reflecting a line-item start in FY 1995. In December 1994, ANS management decided to prepare a significantly lower-cost option for a research facility based on ANS which could be considered during FY 1997 budget deliberations if DOE or Congressional planners wished. A cost reduction for ANS of about $1 billion was desired for this new option. It was decided that such a cost reduction could be achieved only by a significant reduction in the ANS research scope and by maximum, cost-effective use of existing High Flux Isotope Reactor (HFIR) and ORNL facilities to minimize the need for new buildings. However, two central missions of the ANS -- neutron scattering research and isotope production-were to be retained. The title selected for this new option was High Flux Isotope Reactor-Center for Neutron Research (HFIR-CNR) because of the project's maximum use of existing HFIR facilities and retention of selected, central ANS missions. Assuming this shared-facility requirement would necessitate construction work near HFIR, it was specified that HFIR-CNR construction should not disrupt normal operation of HFIR. Additional objectives of the study were that it be highly credible and that any material that might be needed for US Department of Energy (DOE) and Congressional deliberations be produced quickly using minimum project resources. This requirement made it necessary to rely heavily on the ANS design, cost, and schedule baselines. A workshop methodology was selected because assessment of each cost and/or scope-reduction idea required nearly continuous communication among project personnel to ensure that all ramifications of propsed changes

Establishing a Cost Basis for Converting the High Flux Isotope Reactor from High Enriched to Low Enriched Uranium Fuel

International Nuclear Information System (INIS)

Primm, Trent; Guida, Tracey

2010-01-01

Under the auspices of the Global Threat Reduction Initiative Reduced Enrichment for Research and Test Reactors Program, the National Nuclear Security Administration/Department of Energy (NNSA/DOE) has, as a goal, to convert research reactors worldwide from weapons grade to non-weapons grade uranium. The High Flux Isotope Reactor (HFIR) at Oak Ridge National Lab (ORNL) is one of the candidates for conversion of fuel from high enriched uranium (HEU) to low enriched uranium (LEU). A well documented business model, including tasks, costs, and schedules was developed to plan the conversion of HFIR. Using Microsoft Project, a detailed outline of the conversion program was established and consists of LEU fuel design activities, a fresh fuel shipping cask, improvements to the HFIR reactor building, and spent fuel operations. Current-value costs total $76 million dollars, include over 100 subtasks, and will take over 10 years to complete. The model and schedule follows the path of the fuel from receipt from fuel fabricator to delivery to spent fuel storage and illustrates the duration, start, and completion dates of each subtask to be completed. Assumptions that form the basis of the cost estimate have significant impact on cost and schedule.

Isotope separation process

International Nuclear Information System (INIS)

Kaldor, A.; Rabinowitz, P.

1979-01-01

A method of separating the isotopes of an element is described, which comprises the steps of (i) subjecting molecules of a gaseous compound of the element simultaneously to two infrared radiations of different wavelengths, the first radiation having a wavelength which corresponds to an absorption band of the compound, which in turn corresponds to a mode of molecular motion in which there is participation by atoms of the element, and the second radiation having a power density greater than 10 6 watts per cm 2 , thereby exciting molecules of the compound in an isotopically selective manner, this step being conducted in such manner that the excited molecules either receive a level of energy sufficient to cause them to undergo conversion by unimolecular decomposition or receive a level of energy sufficient to cause them to undergo conversion by reaction with molecules of another gas present for that purpose; and (ii) separating and recovering converted molecules from unconverted molecules. (author)

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.)

Why high energy physics

International Nuclear Information System (INIS)

Diddens, A.N.; Van de Walle, R.T.

1981-01-01

An argument is presented for high energy physics from the point of view of the practitioners. Three different angles are presented: The cultural consequence and scientific significance of practising high energy physics, the potential application of the results and the discovery of high energy physics, and the technical spin-offs from the techniques and methods used in high energy physics. (C.F.)

Measurement of mass and isotopic fission yields for heavy fission products with the LOHENGRIN mass spectrometer

International Nuclear Information System (INIS)

Bail, A.

2009-05-01

In spite of the huge amount of fission yield data available in different libraries, more accurate values are still needed for nuclear energy applications and to improve our understanding of the fission process. Thus measurements of fission yields were performed at the mass spectrometer Lohengrin at the Institut Laue-Langevin in Grenoble, France. The mass separator Lohengrin is situated at the research reactor of the institute and permits the placement of an actinide layer in a high thermal neutron flux. It separates fragments according to their atomic mass, kinetic energy and ionic charge state by the action of magnetic and electric fields. Coupled to a high resolution ionization chamber the experiment was used to investigate the mass and isotopic yields of the light mass region. Almost all fission yields of isotopes from Th to Cf have been measured at Lohengrin with this method. To complete and improve the nuclear data libraries, these measurements have been extended in this work to the heavy mass region for the reactions 235 U(n th ,f), 239 Pu(n th ,f) and 241 Pu(n th ,f). For these higher masses an isotopic separation is no longer possible. So, a new method was undertaken with the reaction 239 Pu(n th ,f) to determine the isotopic yields by spectrometry. These experiments have allowed to reduce considerably the uncertainties. Moreover the ionic charge state and kinetic energy distributions were specifically studied and have shown, among others, nanosecond isomers for some masses. (author)

Evolution of single-particle structure of silicon isotopes

Energy Technology Data Exchange (ETDEWEB)

Bespalova, O.V.; Klimochkina, A.A.; Spasskaya, T.I.; Tretyakova, T.Yu. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Fedorov, N.A.; Markova, M.L. [Lomonosov Moscow State University, Faculty of Physics, Moscow (Russian Federation)

2018-01-15

New data on proton and neutron single-particle energies E{sub nlj} of Si isotopes with neutron number N from 12 to 28 as well as occupation probabilities N{sub nlj} of single-particle states of stable isotopes {sup 28,30}Si near the Fermi energy were obtained by the joint evaluation of the stripping and pick-up reaction data and excited state decay schemes of neighboring nuclei. The evaluated data indicate the following features of single-particle structure evolution: persistence of Z = 14 subshell closure with N increase, the new magicity of the number N = 16, and the conservation of the magic properties of the number N = 20 in Si isotopic chain. The features were described by the dispersive optical model. The calculation also predicts the weakening of N = 28 shell closure and demonstrates evolution of a bubble-like structure of the proton density distributions in neutron-rich Si isotopes. (orig.)

Production of stable isotopes utilizing the plasma separation process

Science.gov (United States)

Bigelow, T. S.; Tarallo, F. J.; Stevenson, N. R.

2005-12-01

A plasma separation process (PSP) is being operated at Theragenics Corporation's®, Oak Ridge, TN, facility for the enrichment of stable isotopes. The PSP utilizes ion cyclotron mass discrimination to separate isotopes on a relatively large scale. With a few exceptions, nearly any metallic element could be processed with PSP. Output isotope enrichment factor depends on natural abundance and mass separation and can be fairly high in some cases. The Theragenics™ PSP facility is believed to be the only such process currently in operation. This system was developed and formerly operated under the US Department of Energy Advanced Isotope Separation program. Theragenics™ also has a laboratory at the PSP site capable of harvesting the isotopes from the process and a mass spectrometer system for analyzing enrichment and product purity. Since becoming operational in 2002, Theragenics™ has utilized the PSP to separate isotopes of several elements including: dysprosium, erbium, gadolinium, molybdenum and nickel. Currently, Theragenics™ is using the PSP for the separation of 102Pd, which is used as precursor for the production of 103Pd. The 103Pd radioisotope is the active ingredient in TheraSeed®, which is used in the treatment of early stage prostate cancer and being investigated for other medical applications. New industrial, medical and research applications are being investigated for isotopes that can be enriched on the PSP. Pre-enrichment of accelerator or reactor targets offers improved radioisotope production. Theragenics operates 14 cyclotrons for proton activation and has access to HFIR at ORNL for neutron activation of radioisotopes.

Microscopic insight in the study of yrast bands in selenium isotopes

Indian Academy of Sciences (India)

the rotational-like energy spacings of the yrast states with I≥6. ... even–even selenium isotopes, the study of structure of high spin states through mea- ... calculations with this model can achieve a comparable quality to the large-scale ... model in that the PSM uses the angular momentum projected states as the basis.

Eddy-current inspection of high flux isotope reactor nuclear control rods

International Nuclear Information System (INIS)

Smith, J.H.; Chitwood, L.D.

1981-07-01

Inner control rods for the High Flux Isotope Reactor were nondestructively inspected for defects by eddy-current techniques. During these examinations aluminum cladding thickness and oxide thickness on the cladding were also measured. Special application techniques were required because of the high-radiation levels (approx. 10 5 R/h at 30 cm) present and the relatively large temperature gradients that occurred on the surface of the control rods. The techniques used to perform the eddy-current inspections and the methods used to reduce the associated data are described

Temperature and isotope effects on the shape of the optical absorption spectrum of solvated electrons in water

International Nuclear Information System (INIS)

Jou, F.Y.; Freeman, G.R.

1979-01-01

The optical absorption spectra of solvated electrons in H 2 O and D 2 O have been measured at 274, 298, 340, and 380 K. All the spectra were fitted very well with the Gaussian and Lorentzian shape functions at the low- and high-energy sides of the absorption maximum, respectively, excluding the high-energy tail. The spectrum does not shift uniformly with temperature. The temperature coefficient of absorption decreases rapidly with increasing energy on the low-energy side of the absorption maximum, while it changes only slightly on the high-energy side. When the temperature increases the Lorentzian width remains constant, the Gaussian width varies proportionally to T/sup 1/2/, and the spectrum becomes more symmetrical. On going from H 2 O to D 2 O we found that the spectrum at a given A/A/sub max/ shows a shift of +0.05 eV in the low-energy wing. The shift decreases with increasing energy, reaching 0.03 eV at the absorption maximum. On the high-energy side of the band the shift becomes negative at hν > 2.2 eV. The shift on the low-energy side seems to be related to the difference of the zero-point energies of the inter- and intramolecular vibrations. The wavelength dependence of the temperature and isotope effects is consistent with the model that different types of excitation occur on the low- and high-energy sides of the absorption band. The temperature and isotopic dependence of the low-energy side are consistent with its width being due to phonon interactions

High-precision mass spectrometric analysis using stable isotopes in studies of children

NARCIS (Netherlands)

Schierbeek, Henk; van den Akker, Chris H. P.; Fay, Laurent B.; van Goudoever, Johannes B.

2012-01-01

The use of stable isotopes combined with mass spectrometry (MS) provides insight into metabolic processes within the body. Herein, an overview on the relevance of stable isotope methodology in pediatric research is presented. Applications for the use of stable isotopes with MS cover carbohydrate,

Advanced concepts for gamma-ray isotopic analysis and instrumentation

International Nuclear Information System (INIS)

Buckley, W.M.; Carlson, J.B.

1994-07-01

The Safeguards Technology Program at the Lawrence Livermore National Laboratory is developing actinide isotopic analysis technologies in response to needs that address issues of flexibility of analysis, robustness of analysis, ease-of-use, automation and portability. Recent developments such as the Intelligent Actinide Analysis System (IAAS), begin to address these issues. We are continuing to develop enhancements on this and other instruments that improve ease-of-use, automation and portability. Requests to analyze samples with unusual isotopics, contamination, or containers have made us aware of the need for more flexible and robust analysis. We have modified the MGA program to extend its plutonium isotopic analysis capability to samples with greater 241 Am content or U isotopics. We are looking at methods for dealing with tantalum or lead contamination and contamination with high-energy gamma emitters, such as 233 U. We are looking at ways to allow the program to use additional information about the sample to further extend the domain of analyzable samples. These unusual analyses will come from the domain of samples that need to be measured because of complex reconfiguration or environmental cleanup

Germanium-76 Isotope Separation by Cryogenic Distillation. Final Report

International Nuclear Information System (INIS)

Stohler, Eric

2007-01-01

The current separation method for Germanium isotopes is electromagnetic separation using Calutrons. The Calutrons have the disadvantage of having a low separation capacity and a high energy cost to achieve the separation. Our proposed new distillation method has the advantage that larger quantities of Germanium isotopes can be separated at a significantly lower cost and in a much shorter time. After nine months of operating the column that is 1.5 meter in length, no significant separation of the isotopes has been measured. We conclude that the length of the column we have been using is too short. In addition, other packing material than the 0.16 inch Propak, 316 ss Protruded metal packing that we used in the column, should be evaluated which may have a better separation factor than the 0.16 inch Propak, 316 ss Protruded metal packing that has been used. We conclude that a much longer column - a minimum of 50 feet length - should be built and additional column packing should be tested to verify that isotopic separation can be achieved by cryogenic distillation. Even a longer column than 50 feet would be desirable.

Reactions of neutron-rich Sn isotopes investigated at relativistic energies at R{sup 3}B

Energy Technology Data Exchange (ETDEWEB)

Schindler, Fabia; Aumann, Thomas; Johansen, Jacob; Schrock, Philipp [IKP, TU Darmstadt (Germany); Boretzky, Konstanze [GSI Helmholtzzentrum (Germany); Collaboration: R3B-Collaboration

2015-07-01

Reactions of neutron-rich tin isotopes in a mass range of A=124 to A=134 have been measured at the R{sup 3}B setup at GSI in inverse kinematics. Due to the neutron excess, which results in a weaker binding of the valence neutrons such isotopes are expected to form a neutron skin. The investigation of this phenomenon is an important goal in nuclear-structure physics. Reactions of the tin isotopes with different targets have been performed kinematically complete. The taken data set therefore allows for the extraction of the neutron-skin thickness from two independent reaction channels. These are dipole excitations on the one hand and nuclear-induced reactions on the other hand. This contribution focuses on the latter mechanism. The analysis techniques which are used to extract the total charge-changing as well as the total neutron-removal cross section are presented using the example of {sup 124}Sn. The total neutron-removal cross section is of particular interest because of its high sensitivity to the neutron-skin thickness.

P-odd effects in πN-scattering at low energies and determination of the isotopical structure of the weak nonleptonic interaction

International Nuclear Information System (INIS)

Gershtein, S.S.; Folomeshkin, V.N.; Khlopov, M.Yu.

1974-01-01

P-odd effects in the πN-scattering on a target polarized along and again a pion beam have been considered. The P-odd correlations are intensified by interference of weak and strong interactions, whose amplitude is great in the energy range of the order of 100 to 300 MeV. When measuring cross-section differences of the πN-scattering at meson factories, it is possible to hope that the Lobashow integral method may be used in this range. The P-odd amplitudes have been calculated in the approximation of low-energy pions from the P-odd πNN vertex. High-energy meson effects are taken account of in the model of a rho-meson exchange. A kinematic analysis shows that the P-odd effects in a backward charge exchange reaction are sensitive to the presence of neutral currents. Investigation of the P-odd effects in a forward (elastica and with charge exchange) πN-scattering makes it possible to establish the isotopic structure of the nonlepton weak interaction and in particular to check the assumption of an intensified rho-meson exchange which has been offered by. Danilov to explain the high value of circular polarization of γ-quanta in the np → dγ reaction

Analyzing powers and isotope ratios for the natAg(rvec p, intermediate-mass fragment) reaction at 200 MeV

International Nuclear Information System (INIS)

Renshaw, E.; Yennello, S.J.; Kwiatkowski, K.; Planeta, R.; Woo, L.W.; Viola, V.E.

1991-01-01

Analyzing powers and isotope ratios have been measured for ejectiles with Z≤7 emitted at forward angles in the 200-MeV rvec p+ nat Ag reaction. The observed analyzing powers are consistent with zero, and thus do not provide evidence for a significant contribution from cluster knockout, or similar direct formation mechanisms. Fragment kinetic-energy spectra above the Coulomb peak are compared with a coalescence calculation. The isotopic composition of the elemental kinetic-energy spectra is found to favor N/Z≥1 nuclei for fragment energies near the exit-channel Coulomb energy, whereas species with N/Z≤1 are more abundant in the high-energy spectral tails. This behavior is consistent with the predictions of an accreting source calculation

Automated Sample Preparation for Radiogenic and Non-Traditional Metal Isotopes: Removing an Analytical Barrier for High Sample Throughput

Science.gov (United States)

Field, M. Paul; Romaniello, Stephen; Gordon, Gwyneth W.; Anbar, Ariel D.; Herrmann, Achim; Martinez-Boti, Miguel A.; Anagnostou, Eleni; Foster, Gavin L.

2014-05-01

MC-ICP-MS has dramatically improved the analytical throughput for high-precision radiogenic and non-traditional isotope ratio measurements, compared to TIMS. The generation of large data sets, however, remains hampered by tedious manual drip chromatography required for sample purification. A new, automated chromatography system reduces the laboratory bottle neck and expands the utility of high-precision isotope analyses in applications where large data sets are required: geochemistry, forensic anthropology, nuclear forensics, medical research and food authentication. We have developed protocols to automate ion exchange purification for several isotopic systems (B, Ca, Fe, Cu, Zn, Sr, Cd, Pb and U) using the new prepFAST-MC™ (ESI, Nebraska, Omaha). The system is not only inert (all-flouropolymer flow paths), but is also very flexible and can easily facilitate different resins, samples, and reagent types. When programmed, precise and accurate user defined volumes and flow rates are implemented to automatically load samples, wash the column, condition the column and elute fractions. Unattended, the automated, low-pressure ion exchange chromatography system can process up to 60 samples overnight. Excellent reproducibility, reliability, recovery, with low blank and carry over for samples in a variety of different matrices, have been demonstrated to give accurate and precise isotopic ratios within analytical error for several isotopic systems (B, Ca, Fe, Cu, Zn, Sr, Cd, Pb and U). This illustrates the potential of the new prepFAST-MC™ (ESI, Nebraska, Omaha) as a powerful tool in radiogenic and non-traditional isotope research.

Modeling and Depletion Simulations for a High Flux Isotope Reactor Cycle with a Representative Experiment Loading

Energy Technology Data Exchange (ETDEWEB)

Chandler, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Betzler, Ben [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Hirtz, Gregory John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Ilas, Germina [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Sunny, Eva [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division

2016-09-01

The purpose of this report is to document a high-fidelity VESTA/MCNP High Flux Isotope Reactor (HFIR) core model that features a new, representative experiment loading. This model, which represents the current, high-enriched uranium fuel core, will serve as a reference for low-enriched uranium conversion studies, safety-basis calculations, and other research activities. A new experiment loading model was developed to better represent current, typical experiment loadings, in comparison to the experiment loading included in the model for Cycle 400 (operated in 2004). The new experiment loading model for the flux trap target region includes full length ²⁵²Cf production targets, ⁷⁵Se production capsules, ⁶³Ni production capsules, a ¹⁸⁸W production capsule, and various materials irradiation targets. Fully loaded ²³⁸Pu production targets are modeled in eleven vertical experiment facilities located in the beryllium reflector. Other changes compared to the Cycle 400 model are the high-fidelity modeling of the fuel element side plates and the material composition of the control elements. Results obtained from the depletion simulations with the new model are presented, with a focus on time-dependent isotopic composition of irradiated fuel and single cycle isotope production metrics.

Analysis of high burnup pressurized water reactor fuel using uranium, plutonium, neodymium, and cesium isotope correlations with burnup

International Nuclear Information System (INIS)

Kim, Jung Suk; Jeon, Young Shin; Park, Soon Dal; Ha, Yeong Keong; Song, Kyu Seok

2015-01-01

The correlation of the isotopic composition of uranium, plutonium, neodymium, and cesium with the burnup for high burnup pressurized water reactor fuels irradiated in nuclear power reactors has been experimentally investigated. The total burnup was determined by Nd-148 and the fractional 235 U burnup was determined by U and Pu mass spectrometric methods. The isotopic compositions of U, Pu, Nd, and Cs after their separation from the irradiated fuel samples were measured using thermal ionization mass spectrometry. The contents of these elements in the irradiated fuel were determined through an isotope dilution mass spectrometric method using 233 U, 242 Pu, 150 Nd, and 133 Cs as spikes. The activity ratios of Cs isotopes in the fuel samples were determined using gamma-ray spectrometry. The content of each element and its isotopic compositions in the irradiated fuel were expressed by their correlation with the total and fractional burnup, burnup parameters, and the isotopic compositions of different elements. The results obtained from the experimental methods were compared with those calculated using the ORIGEN-S code

HIGH ENERGY RADIOGRAPHY-1-30 Mev

Energy Technology Data Exchange (ETDEWEB)

Bly, James H.

1963-10-15

From 1963 American Society of Metals/Materials Show, Cleveland, Oct. 1963. A survey of the field of radiographic inspection of thick sections, at one million volts energy or more, shows that this field has become a major branch of radiographic testing. More than a dozen models of x-ray generators are now commercially available in this field, over the range from 1 to 31 Mev, with outputs up to more than two orders of magnitude greater than can be obtained from radiographic isotope sources, and with smaller spot size. A study of the radiographic characteristics of x rays in this region shows that energies available cover the range of minimum absorption and scattering for most materials and approach this range for solid propellant; at higher energies severe coverage restrictions are imposed; output powers on small spots are near the limits of present target technology. It would appear that some degree of technological maturity'' has been achieved. Radiographic technique at 1 to 30 Mev is straightforward, following the same basic principles as in conventional radiography. Specialized aspects of technique are individually discussed. The wellknown 1 and 2 million volt equlpments are supplemented by a wide variety of higher-energy machines, with energy and output ratings to satisfy almost any radiographic need. Some examples are epitomized, and a brief discussion of possible future developments is presented. (auth)

ChelomEx: Isotope-assisted discovery of metal chelates in complex media using high-resolution LC-MS.

Science.gov (United States)

Baars, Oliver; Morel, François M M; Perlman, David H

2014-11-18

Chelating agents can control the speciation and reactivity of trace metals in biological, environmental, and laboratory-derived media. A large number of trace metals (including Fe, Cu, Zn, Hg, and others) show characteristic isotopic fingerprints that can be exploited for the discovery of known and unknown organic metal complexes and related chelating ligands in very complex sample matrices using high-resolution liquid chromatography mass spectrometry (LC-MS). However, there is currently no free open-source software available for this purpose. We present a novel software tool, ChelomEx, which identifies isotope pattern-matched chromatographic features associated with metal complexes along with free ligands and other related adducts in high-resolution LC-MS data. High sensitivity and exclusion of false positives are achieved by evaluation of the chromatographic coherence of the isotope pattern within chromatographic features, which we demonstrate through the analysis of bacterial culture media. A built-in graphical user interface and compound library aid in identification and efficient evaluation of results. ChelomEx is implemented in MatLab. The source code, binaries for MS Windows and MAC OS X as well as test LC-MS data are available for download at SourceForge ( http://sourceforge.net/projects/chelomex ).

Future trends in the application of isotopes and radiation

Energy Technology Data Exchange (ETDEWEB)

Glubrecht, H [Institut fuer Biophysik, Technische Universitaet Hannover (Germany)

1977-12-15

medicine and biomedical research is radioimmunoassay (RIA). Measurement of elemental composition of human body samples also has a high diagnostic value for large-scale screening of infectious and non-infectious diseases. Strong increase is to be foreseen in the application of gauges and other radiation analytical methods. Promising techniques in the petrol industry are the quantitative determination of hydrocarbon saturation by the use of pulsed-neutron capture logs and logs based on measurements of gamma rays from inelastic neutron scattering. Mineral exploration and mining may strongly profit from the development of portable EDXRF instruments using isotopic sources and high resolution Si(Li) detectors. In basic studies of process dynamics, tracer techniques may play an increasing role, particularly in the optimization of low-grade ore exploitation. Ionizing radiation can produce cross-linking and grafting in plastic and rubber. It is to be expected that more attention will be paid to these energy-saving processes in the future. The use of ?natural? isotope measurements ({sup 14}C, {sup 3}H) and of isotope ratios ({sup 2}H/{sup 1}H, {sup 18}O/{sup 16}O) has probably reached the highest level of sophistication in its application to problems associated with the assessment of water resources. The world-wide energy problem has prompted a new assessment of the potential of geothermal sources of energy. Environmental isotopes are being used in the hydrological study of geothermal systems environmental control and monitoring without making use of nuclear methods. NAA and EDXRF allow fast screening of more than 30 elements of importance in environmental pollution control. Future trends can be described by extrapolating from the present situation. Although the trends discussed in this paper may change it is clear that isotopes and radiation have an increasingly wide field of application i and strong future developments.

Study on ground state energy band of even 114-124Cd isotopes under the framework of interacting boson model (IBM-1)

International Nuclear Information System (INIS)

Hossain, I.; Abdullah, Hewa Y.; Ahmed, I.M.; Saeed, M.A.; Ahmad, S.T.

2012-01-01

In this research, the ground state gamma ray bands of even 114-124 Cd isotopes are calculated using interacting boson model (IBM-1). The theoretical energy levels for Z = 48, N = 66–76 up to spin-parity 8 + have been obtained by using PHINT computer program. The values of the parameters in the IBM-1 Hamiltonian yield the best fit to the experimental energy spectrum. The calculated results of the ground state energy band are compared to the previous experimental results and the obtained theoretical calculations in IBM-1 are in good agreement with the experimental energy level. (author)

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by Emiliania huxleyi

Directory of Open Access Journals (Sweden)

G. M. Weiss

2017-12-01

Full Text Available Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by Emiliania huxleyi

Science.gov (United States)

Weiss, Gabriella M.; Pfannerstill, Eva Y.; Schouten, Stefan; Sinninghe Damsté, Jaap S.; van der Meer, Marcel T. J.

2017-12-01

Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

Sources of Radioactive Isotopes for Dirty Bombs

Science.gov (United States)

Lubenau, Joel

2004-05-01

From the security perspective, radioisotopes and radioactive sources are not created equal. Of the many radioisotopes used in industrial applications, medical treatments, and scientific research, only eight, when present in relatively large amounts in radioactive sources, pose high security risks primarily because of their prevalence and physical properties. These isotopes are americium-241, californium-252, cesium-137, cobalt-60, iridium-192, radium-226, plutonium-238, and strontium-90. Except for the naturally occurring radium-226, nuclear reactors produce the other seven in bulk commercial quantities. Half of these isotopes emit alpha radiation and would, thus, primarily pose internal threats to health; the others are mainly high-energy gamma emitters and would present both external and internal health hazards. Therefore, the response to a "dirty bomb" event depends on what type of radioisotope is chosen and how it is employed. While only a handful of major corporations produce the reactor-generated radioisotopes, they market these materials to thousands of smaller companies and users throughout the world. Improving the security of the high-risk radioactive sources will require, among other efforts, cooperation among source suppliers and regulatory agencies.

Chemical analyses and calculation of isotopic compositions of high-burnup UO{sub 2} fuels and MOX fuels

Energy Technology Data Exchange (ETDEWEB)

Matsumura, Tetsuo; Sasahara, Akihiro [Central Research Inst. of Electric Power Industry, Tokyo (Japan)

2001-08-01

Chemical analysis activities of isotopic compositions of high-burnup UO{sub 2} fuels and MOX fuels in CRIEPI and calculation evaluation are reviewed briefly. C/E values of ORIGEN2, in which original libraries and JENDL-3.2 libraries are used, and other codes with chemical analysis data are reviewed and evaluated. Isotopic compositions of main U and Pu in fuels can be evaluated within 10% relative errors by suitable libraries and codes. Void ratio is effective parameter for C/E values in BWR fuels. JENDL-3.2 library shows remarkable improvement compared with original libraries in isotopic composition evaluations of FP nuclides. (author)

High burn-up plutonium isotopic compositions recommended for use in shielding analysis

International Nuclear Information System (INIS)

Zimmerman, M.G.

1977-06-01

Isotopic compositions for plutonium generated and recycled in LWR's were estimated for use in shielding calculations. The values were obtained by averaging isotopic values from many sources in the literature. These isotopic values should provide the basis for a reasonable prediction of exposure rates from the range of LWR fuel expected in the future. The isotopic compositions given are meant to be used for shielding calculations, and the values are not necessarily applicable to other forms of analysis, such as inventory assessment or criticality safety. 11 tables, 2 figs

Stable carbon isotopes in high-productive littoral areas of Lake Constance

International Nuclear Information System (INIS)

Chondrogianni, C.

1992-01-01

The investigation attempted to extend understanding of C fractionation in aquatic systems and to facilitate the interpretation of palaeolimnological isotope data. Particular interest was taken in the aspect of bicarbonate assimilation at high productivity and in the exchange processes between water and atmosphere. Littoral areas of lakes were chosen as areas of investigation as they offer a high-productivity environment with large populations of submersed macrophytes and periphytes. To get a better picture of the factors influencing C fractionation, litteral and pellagial regions were compared on the one hand and a mesotrophic (Ueberlingersee) and a eutrophic (Gnadensee) lake section on the other hand. Further factors of differentiation between the two lake parts were: Volume, the proportional share of the litteral area, and water exchange. Two main fields of interest were investigated: - Determination of the C isotope ratio (δ 13 C) in the dissolved bicarbonate of water in the sediments of a single year for the purpose of calibrating its fractionation in the basis of the present chemical and physical status of the lake water (water programme). - Determination of δ 13 C in selected carbonate components from sedimentary cores in order to find out about palaeolimnological events in the areas of investigation (sediment programme). (orig.) [de

Derivation of Apollo 14 High-Al Basalts at Discrete Times: Rb-Sr Isotopic Constraints

Science.gov (United States)

Hui, H.; Neal, C. R.; Shih, C.-Y.; Nyquist, L. E.

2012-03-01

Four eruption episodes were identified for A-14 high-Al basalts. Rb-Sr isotopic data and ITE ratios show that their parental melt compositions of are correlated through mixing of evolved components with a relatively primitive magma ocean cumulate.

Isotope ratio measurements of uranium by LA-HR-ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Marin, Rafael C.; Sarkis, Jorge E.S., E-mail: rafael.marin@usp.b, E-mail: jesarkis@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

This work describes the utilization of Laser Ablation High Resolution Inductively Mass Spectrometry (LA-HR-ICP-MS) technique for the determination of uranium isotope composition in a UO{sub 2} pellet (CRM -125A) supplied and certified by the New Brunswick Laboratory (NBL). To carry out the adjustments of the parameters was used a glass standard NIST 610, supplied and certified by National Institute of Standards and Technology (NIST). The precision of the measurements were improved by adjusting the following parameters: RF power, laser beam diameter, defocusing of laser beam, laser energy, laser energy-density, auxiliary gas and sample gas. The measurements were performed on a continuous ablation with low energy density and defocusing, which demonstrated to be the optimum to reach the best signal stability. Isotope ratios, {sup 234}U/{sup 238}U, {sup 235}U/{sup 238}U and {sup 236}U/{sup 238}U were measured, reaching relative standard deviations (RSD) from 1.55% to 7.60%. The parameters which caused the greatest impact in order to improve the signal stability were RF power, defocusing and laser beam diameter. The results presented by the measurements revealed that the Laser ablation ICP-MS technique offers a rapid and accurate way to perform uranium isotope ratios without any sample preparation, since it allows carrying out the measurements straight on the sample, besides to preserve the testimony that is very important for safeguards and nuclear forensics purposes. (author)

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

Proposal for a coordination research programme (CRP) of the International Atomic Energy Agency (IAEA) on stable isotope tracer techniques for studies on protein-energy interactions

International Nuclear Information System (INIS)

Shetty, P.; James, W.P.T.

1993-01-01

This Report provides a rationale and justification for the initiation of a Coordinated Research programme to support studies using stable isotopic tracer techniques to address priority areas of human protein-energy interactions with special emphasis on the problems of human nutrition in developing countries. The Report suggests a modus for establishing such a practically oriented Coordinated Research Programme under the aegis of the International Atomic Energy Agency with concrete suggestions for its organization and the identification of probable participants in such a programme. The likely sources of additional funding to sustain such an activity viable for a period of 4 to 5 years are also indicated. 8 refs

Isotope and fast ions turbulence suppression effects: Consequences for high-β ITER plasmas

Science.gov (United States)

Garcia, J.; Görler, T.; Jenko, F.

2018-05-01

The impact of isotope effects and fast ions on microturbulence is analyzed by means of non-linear gyrokinetic simulations for an ITER hybrid scenario at high beta obtained from previous integrated modelling simulations with simplified assumptions. Simulations show that ITER might work very close to threshold, and in these conditions, significant turbulence suppression is found from DD to DT plasmas. Electromagnetic effects are shown to play an important role in the onset of this isotope effect. Additionally, even external ExB flow shear, which is expected to be low in ITER, has a stronger impact on DT than on DD. The fast ions generated by fusion reactions can additionally reduce turbulence even more although the impact in ITER seems weaker than in present-day tokamaks.

U and Pb isotope analysis of uraninite and galena by ion microprobe

Energy Technology Data Exchange (ETDEWEB)

Evins, L.Z.; Sunde, T.; Schoeberg, H. [Swedish Museum of Natural History, Stockholm (Sweden). Laboratory for Isotope Geology; Fayek, M. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences

2001-10-01

Accurate isotopic analysis of minerals by ion microprobe, or SIMS (Secondary Ion Mass Spectrometry) usually requires a standard to correct for instrumental mass bias effects that occur during analysis. We have calibrated two uraninite crystals and one galena crystal to be used as ion probe standards. As part of this study we describe the analytical procedures and problems encountered while trying to establish fractionation factors for U and Pb isotopes measured in galena and uraninite. Only the intra-element isotopic mass fractionation is considered and not the interelement fractionation. Galena and uraninite were analysed with TIMS (Thermal Ionisation Mass Spectrometry) prior to SIMS. One uraninite crystal (P88) comes from Sweden and is ca 900 Ma old, the other from Maine, USA (LAMNH-30222) and is ca 350 Ma old. The galena sample comes from the Paleoproterozoic ore district Bergslagen in Sweden. SIMS analyses were performed at two different laboratories: the NORDSM facility in Stockholm, which has a high resolution Cameca IMS 1270 ion microprobe, and the Oak Ridge National Laboratory (ORNL) in Tennessee, which has a Cameca IMS 4f ion microprobe. The results show that during the analysis of galena, Pb isotopes fractionate in favour of the lighter isotope by as much as 0.5%/amu. A Pb isotope fractionation factor for uraninite was more difficult to calculate, probably due to the formation of hydride interferences encountered during analysis with the Cameca IMS 1270 ion microprobe. However, drying the sample in vacuum prior to analysis, and using high-energy filtering and a cold trap during analysis can minimise these hydride interferences. A large fractionation of U isotopes of ca 1.4%/amu in favour of the lighter isotope was calculated for uraninite.

U and Pb isotope analysis of uraninite and galena by ion microprobe

International Nuclear Information System (INIS)

Evins, L.Z.; Sunde, T.; Schoeberg, H.; Fayek, M.

2001-10-01

Accurate isotopic analysis of minerals by ion microprobe, or SIMS (Secondary Ion Mass Spectrometry) usually requires a standard to correct for instrumental mass bias effects that occur during analysis. We have calibrated two uraninite crystals and one galena crystal to be used as ion probe standards. As part of this study we describe the analytical procedures and problems encountered while trying to establish fractionation factors for U and Pb isotopes measured in galena and uraninite. Only the intra-element isotopic mass fractionation is considered and not the interelement fractionation. Galena and uraninite were analysed with TIMS (Thermal Ionisation Mass Spectrometry) prior to SIMS. One uraninite crystal (P88) comes from Sweden and is ca 900 Ma old, the other from Maine, USA (LAMNH-30222) and is ca 350 Ma old. The galena sample comes from the Paleoproterozoic ore district Bergslagen in Sweden. SIMS analyses were performed at two different laboratories: the NORDSM facility in Stockholm, which has a high resolution Cameca IMS 1270 ion microprobe, and the Oak Ridge National Laboratory (ORNL) in Tennessee, which has a Cameca IMS 4f ion microprobe. The results show that during the analysis of galena, Pb isotopes fractionate in favour of the lighter isotope by as much as 0.5%/amu. A Pb isotope fractionation factor for uraninite was more difficult to calculate, probably due to the formation of hydride interferences encountered during analysis with the Cameca IMS 1270 ion microprobe. However, drying the sample in vacuum prior to analysis, and using high-energy filtering and a cold trap during analysis can minimise these hydride interferences. A large fractionation of U isotopes of ca 1.4%/amu in favour of the lighter isotope was calculated for uraninite

Carbon and hydrogen isotope fractionation under continuous light: implications for paleoenvironmental interpretations of the High Arctic during Paleogene warming.

Science.gov (United States)

Yang, Hong; Pagani, Mark; Briggs, Derek E G; Equiza, M A; Jagels, Richard; Leng, Qin; Lepage, Ben A

2009-06-01

The effect of low intensity continuous light, e.g., in the High Arctic summer, on plant carbon and hydrogen isotope fractionations is unknown. We conducted greenhouse experiments to test the impact of light quantity and duration on both carbon and hydrogen isotope compositions of three deciduous conifers whose fossil counterparts were components of Paleogene Arctic floras: Metasequoia glyptostroboides, Taxodium distichum, and Larix laricina. We found that plant leaf bulk carbon isotopic values of the examined species were 1.75-4.63 per thousand more negative under continuous light (CL) than under diurnal light (DL). Hydrogen isotope values of leaf n-alkanes under continuous light conditions revealed a D-enriched hydrogen isotope composition of up to 40 per thousand higher than in diurnal light conditions. The isotope offsets between the two light regimes is explained by a higher ratio of intercellular to atmospheric CO(2) concentration (C (i)/C (a)) and more water loss for plants under continuous light conditions during a 24-h transpiration cycle. Apparent hydrogen isotope fractionations between source water and individual lipids (epsilon(lipid-water)) range from -62 per thousand (Metasequoia C(27) and C(29)) to -87 per thousand (Larix C(29)) in leaves under continuous light. We applied these hydrogen fractionation factors to hydrogen isotope compositions of in situ n-alkanes from well-preserved Paleogene deciduous conifer fossils from the Arctic region to estimate the deltaD value in ancient precipitation. Precipitation in the summer growing season yielded a deltaD of -186 per thousand for late Paleocene, -157 per thousand for early middle Eocene, and -182 per thousand for late middle Eocene. We propose that high-latitude summer precipitation in this region was supplemented by moisture derived from regionally recycled transpiration of the polar forests that grew during the Paleogene warming.

Neutron spectra and dosimetric features of isotopic neutron sources: a review

International Nuclear Information System (INIS)

Vega C, H. R.; Martinez O, S. A.

2015-10-01

A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of 24 NaBe, 24 NaD 2 O, 116 InBe, 140 LaBe, 238 PuLi, 239 PuBe, 241 AmB, 241 AmBe, 241 AmF, 241 AmLi, 242 CmBe, 210 PoBe, 226 RaBe, 252 Cf and 252 Cf/D 2 O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

Beam dynamics studies of the ISOLDE post-accelerator for the high intensity and energy upgrade

CERN Document Server

Fraser, M A

2012-01-01

The High Intensity and Energy (HIE) project represents a major upgrade of the ISOLDE (On-Line Isotope Mass Separator) nuclear facility at CERN with a mandate to significantly increase the energy, intensity and quality of the radioactive nuclear beams provided to the European nuclear physics community for research at the forefront of topics such as nuclear structure physics and nuclear astrophysics. The HIE-ISOLDE project focuses on the upgrade of the existing Radioactive ion beam EXperiment (REX) post-accelerator with the addition of a 40MVsuperconducting linac comprising 32 niobium sputter-coated copper quarter-wave cavities operating at 101.28 MHz and at an accelerating gradient close to 6 MV/m. The energy of post-accelerated radioactive nuclear beams will be increased from the present ceiling of 3 MeV/u to over 10 MeV/u, with full variability in energy, and will permit, amongst others, Coulomb interaction and few-nucleon transfer reactions to be carried out on the full inventory of radionuclides available ...

Beam Dynamics Studies of the ISOLDE Post-accelerator for the High Intensity and Energy Upgrade

CERN Document Server

Fraser, Matthew Alexander; Pasini, M

2012-01-01

The High Intensity and Energy (HIE) project represents a major upgrade of the ISOLDE (On-Line Isotope Mass Separator) nuclear facility at CERN with a mandate to significantly increase the energy, intensity and quality of the radioactive nuclear beams provided to the European nuclear physics community for research at the forefront of topics such as nuclear structure physics and nuclear astrophysics. The HIE-ISOLDE project focuses on the upgrade of the existing Radioactive ion beam EXperiment (REX) post-accelerator with the addition of a 40MVsuperconducting linac comprising 32 niobium sputter-coated copper quarter-wave cavities operating at 101.28 MHz and at an accelerating gradient close to 6 MV/m. The energy of post-accelerated radioactive nuclear beams will be increased from the present ceiling of 3 MeV/u to over 10 MeV/u, with full variability in energy, and will permit, amongst others, Coulomb interaction and few-nucleon transfer reactions to be carried out on the full inventory of radionuclides available ...

Propagation of ultra-high-energy cosmic rays and their secondaries with CRPropa

International Nuclear Information System (INIS)

Vliet, Arjen Rene van

2015-04-01

Due to experiments like the Pierre Auger Observatory (Auger) and the Telescope Array (TA), high-statistics data is becoming available on the energy spectrum, the composition and the arrival directions of ultra-high-energy cosmic rays (UHECRs, cosmic rays with energies above ∝ 10 17 eV). To interpret this data in terms of actual astrophysical parameters, or to test astrophysical models against the measured data, dedicated simulations of the propagation of UHECRs from their sources to Earth are needed. To this end, the UHECR propagation code called CRPropa has been developed. It can take into account all relevant interactions with ambient photon backgrounds (pair production, photodisintegration and photopion production) as well as nuclear decay, cosmological evolution effects and deflections in extragalactic and galactic magnetic fields. CRPropa, including its newest features, is described in this thesis. When considering the propagation of ultra-high-energy nuclei, the dominant interaction for most isotopes and energies is photodisintegration. Photodisintegration has been implemented in CRPropa for all relevant isotopes (up to iron) and all relevant photodisintegration channels using cross-section calculations with the publicly-available code called TALYS, including extensions for the low mass numbers. This photodisintegration setup is compared here extensively with the photodisintegration scheme developed by Puget, Stecker and Bredekamp, leading to several improvements on the cross sections implemented in CRPropa. In the interactions of UHECRs with background photon fields, secondary neutrinos and photons, so-called cosmogenic neutrinos and photons, can be created. CRPropa can simulate the production and propagation of these secondary particles as well. The IceCube Neutrino Observatory (IceCube) has recently reported the first observation of extraterrestrial neutrinos in the PeV energy range. In this work is investigated whether these neutrinos could have

Reactor, radioactive isotopes and nuclear energy: their avatars in Venezuela

Energy Technology Data Exchange (ETDEWEB)

Roche, M

1981-03-01

The decision to bring a fair sized (3MW) research reactor to Venezuela, made in 1954 by a single, ambitious and prestige seeking individual working with a dictatorial government, is a clear case of cargo cult, an implicit desire to import industralized countries' science and technology by purchasing key in hand their expensive machine. The reactor has never ceased to experience difficulties since then, not so much of a physical or mechanical, but rather of a human nature and due to the almost grotesque distance between the machine's potentialities and the quantity and quality of personnel available. Demand and motivation have been scarce, because fossil and hydro energy have been so far plentiful. Military motivation was in theory absent. Perspectives have apparently improved, not that a scientific community has been trained and an infrastructure exists. Radioactive isotopes have been widely used in Venezuela, beginning in 1953, for medical practice and biological research. At present about 2.5 million bolivars worth of radioisotopes are imported annually, mostly from the US and to a lesser extent, from UK. Steps are being taken to train nuclear engineers, since most studies thus far indicate the last few years of the century as the time when nuclear energy will begin to enter the picture, and since a period of at least ten years is needed between the decision to build an atomic power plant and the time it goes into operation. Choice of technique has not been made, but an active, although still small, uranium prospecting program has been initiated. It seems as if, by the end of the century, either nuclear energy will have to supplement other sources, or standard of living of Venezuelans - at least that relative minority who can afford to live well - will drop. 2 figures, 2 tables.

Separation of isotopes by cyclical processes

International Nuclear Information System (INIS)

Hamrin, C.E. Jr.; Weaver, K.

1976-01-01

Various isotopes of hydrogen are separated by a cyclic sorption process in which a gas stream containing the isotopes is periodically passed through a high pressure column containing a palladium sorbent. A portion of the product from the high pressure column is passed through a second column at lower pressure to act as a purge. Before the sorbent in the high pressure column becomes saturated, the sequence is reversed with the stream flowing through the former low-pressure column now at high pressure, and a portion of the product purging the former high pressure column now at low pressure. The sequence is continued in cyclic manner with the product being enriched in a particular isotope

Spatial distribution sampling and Monte Carlo simulation of radioactive isotopes

CERN Document Server

Krainer, Alexander Michael

2015-01-01

This work focuses on the implementation of a program for random sampling of uniformly spatially distributed isotopes for Monte Carlo particle simulations and in specific FLUKA. With FLUKA it is possible to calculate the radio nuclide production in high energy fields. The decay of these nuclide, and therefore the resulting radiation field, however can only be simulated in the same geometry. This works gives the tool to simulate the decay of the produced nuclide in other geometries. With that the radiation field from an irradiated object can be simulated in arbitrary environments. The sampling of isotope mixtures was tested by simulating a 50/50 mixture of $Cs^{137}$ and $Co^{60}$. These isotopes are both well known and provide therefore a first reliable benchmark in that respect. The sampling of uniformly distributed coordinates was tested using the histogram test for various spatial distributions. The advantages and disadvantages of the program compared to standard methods are demonstrated in the real life ca...

High linear energy transfer degradation studies simulating alpha radiolysis of TRU solvent extraction processes

Energy Technology Data Exchange (ETDEWEB)

Pearson, Jeremy [Department of Chemical Engineering and Materials Science - University of California Irvine, 916 Engineering Tower, Irvine, CA, 92697 (United States); Miller, George [Department of Chemistry- University of California Irvine, 2046D PS II, Irvine, CA, 92697 (United States); Nilsson, Mikael [Department of Chemical Engineering and Materials Science - University of California Irvine, 916 Engineering Tower, Irvine, CA, 92697 (United States)

2013-07-01

Treatment of used nuclear fuel through solvent extraction separation processes is hindered by radiolytic damage from radioactive isotopes present in used fuel. The nature of the damage caused by the radiation may depend on the radiation type, whether it be low linear energy transfer (LET) such as gamma radiation or high LET such as alpha radiation. Used nuclear fuel contains beta/gamma emitting isotopes but also a significant amount of transuranics which are generally alpha emitters. Studying the respective effects on matter of both of these types of radiation will allow for accurate prediction and modeling of process performance losses with respect to dose. Current studies show that alpha radiation has milder effects than that of gamma. This is important to know because it will mean that solvent extraction solutions exposed to alpha radiation may last longer than expected and need less repair and replacement. These models are important for creating robust, predictable, and economical processes that have strong potential for mainstream adoption on the commercial level. The effects of gamma radiation on solvent extraction ligands have been more extensively studied than the effects of alpha radiation. This is due to the inherent difficulty in producing a sufficient and confluent dose of alpha particles within a sample without leaving the sample contaminated with long lived radioactive isotopes. Helium ion beam and radioactive isotope sources have been studied in the literature. We have developed a method for studying the effects of high LET radiation in situ via {sup 10}B activation and the high LET particles that result from the {sup 10}B(n,a){sup 7}Li reaction which follows. Our model for dose involves solving a partial differential equation representing absorption by 10B of an isentropic field of neutrons penetrating a sample. This method has been applied to organic solutions of TBP and CMPO, two ligands common in TRU solvent extraction treatment processes. Rates

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.

Clay mineralogy, strontium and neodymium isotope ratios in the sediments of two High Arctic catchments (Svalbard)

Science.gov (United States)

Hindshaw, Ruth S.; Tosca, Nicholas J.; Piotrowski, Alexander M.; Tipper, Edward T.

2018-03-01

The identification of sediment sources to the ocean is a prerequisite to using marine sediment cores to extract information on past climate and ocean circulation. Sr and Nd isotopes are classical tools with which to trace source provenance. Despite considerable interest in the Arctic Ocean, the circum-Arctic source regions are poorly characterised in terms of their Sr and Nd isotopic compositions. In this study we present Sr and Nd isotope data from the Paleogene Central Basin sediments of Svalbard, including the first published data of stream suspended sediments from Svalbard. The stream suspended sediments exhibit considerable isotopic variation (ɛNd = -20.6 to -13.4; 87Sr / 86Sr = 0.73421 to 0.74704) which can be related to the depositional history of the sedimentary formations from which they are derived. In combination with analysis of the clay mineralogy of catchment rocks and sediments, we suggest that the Central Basin sedimentary rocks were derived from two sources. One source is Proterozoic sediments derived from Greenlandic basement rocks which are rich in illite and have high 87Sr / 86Sr and low ɛNd values. The second source is Carboniferous to Jurassic sediments derived from Siberian basalts which are rich in smectite and have low 87Sr / 86Sr and high ɛNd values. Due to a change in depositional conditions throughout the Paleogene (from deep sea to continental) the relative proportions of these two sources vary in the Central Basin formations. The modern stream suspended sediment isotopic composition is then controlled by modern processes, in particular glaciation, which determines the present-day exposure of the formations and therefore the relative contribution of each formation to the stream suspended sediment load. This study demonstrates that the Nd isotopic composition of stream suspended sediments exhibits seasonal variation, which likely mirrors longer-term hydrological changes, with implications for source provenance studies based on fixed

The perspectives of fusion energy: The roadmap towards energy production and fusion energy in a distributed energy system

DEFF Research Database (Denmark)

Naulin, Volker; Juul Rasmussen, Jens; Korsholm, Søren Bang

2014-01-01

at very high temperature where all matter is in the plasma state as the involved energies are orders of magnitude higher than typical chemical binding energies. It is one of the great science and engineering challenges to construct a viable power plant based on fusion energy. Fusion research is a world...... The presentation will discuss the present status of the fusion energy research and review the EU Roadmap towards a fusion power plant. Further the cost of fusion energy is assessed as well as how it can be integrated in the distributed energy system......Controlled thermonuclear fusion has the potential of providing an environmentally friendly and inexhaustible energy source for mankind. Fusion energy, which powers our sun and the stars, is released when light elements, such as the hydrogen isotopes deuterium and tritium, fuse together. This occurs...

Development of an EBIS charge breeder for the Rare Isotope Science Project

Science.gov (United States)

Son, Hyock-Jun; Park, Young-Ho; Kondrashev, Sergey; Kim, Jongwon; Lee, Bong Ju; Chung, Moses

2017-10-01

In Korea, a heavy ion accelerator facility called RAON is being designed to produce various rare isotopes for the Rare Isotope Science Project (RISP) (Jeong, 2016) [1], (Moon, 2014) [2]. This facility is designed to use both In-flight Fragment (IF) and Isotope Separation On-Line (ISOL) techniques in order to produce a wide variety of RI beams for nuclear physics experiments. An Electron Beam Ion Source (EBIS) will be used for charge breeding of Rare Isotope (RI) beams in the ISOL system. The charge-to-mass ratio (q/A) of the RI beams after charge breeding is ≥1/4. The highly charged RI beams will be accelerated by a linac post-accelerator and delivered to a low energy (∼18 MeV/u) experimental hall or the IF system. The RAON EBIS will use a 3 A electron gun and a 6 T superconducting solenoid for high capacity, high efficiency, and short breeding time. In front of the charge breeder, an RFQ cooler-buncher will be used to deliver a bunched beam with small emittance to the EBIS charge breeder. The main design of the RAON EBIS has been carried out on the basis of several beam analyses and technical reviews. In this paper, current progress of the development of the RAON EBIS charge breeder will be presented.

Comparison of different methods of determining plutonium content and isotopic composition

International Nuclear Information System (INIS)

Anon.

1986-01-01

At Rockwell Hanford Operations, several different methods are used to determine plutonium content and isotopic composition. These include alpha particle energy analysis, calorimetry/gamma-ray analysis, mass spectrometry, and low energy gamma-ray assay. Each is used in a process control environment and has its advantages and disadvantages in terms of sample matrix, sample preparation, concentration, error ranges, detection limits, and turn around time. Of the methods discussed, special attention is paid to the Plutonium Isotopics Solution Counter, a low energy gamma-ray assay system designed to provide plutonium and americium content and isotopic composition of Pu-238 through Pu-241 and Am-241. It is qualitatively and quantitatively compared to the other methods. A brief description of sample types which the Solution Counter analyzes is presented

Structural isotopic effect of the α/β-phase transition in the vanadium hydride and its influence on the equilibrium coefficient of separation of hydrogen isotopes in the gas-solid system

International Nuclear Information System (INIS)

Magomedbekov, Eh.P.; Bochkarev, A.V.

1999-01-01

Equilibrium coefficient of hydrogen isotope separation (α H-D ) in the system of vanadium hydride VH n (solid, n ∼ 0.7)-H 2 (g) is measured by the counterbalancing method in a circulation facility and by the method of laser desorption at 298, 373, and 437 K. It is shown that the combination of highly anharmonic potential in the lattice octahedral sites and in significant difference in the energy of hydrogen atom coordination for tetra- and octahedral sites is the reason for unusual behaviour of the hydrogen isotope separation coefficient and the difference in crystal structures of vanadium hydride and deuteride [ru

High-precision γ -ray spectroscopy of the cardiac PET imaging isotope 82Rb and its impact on dosimetry

Science.gov (United States)

Nino, M. N.; McCutchan, E. A.; Smith, S. V.; Lister, C. J.; Greene, J. P.; Carpenter, M. P.; Muench, L.; Sonzogni, A. A.; Zhu, S.

2016-02-01

82Rb is a positron-emitting isotope used in cardiac positron emission tomography (PET) imaging which has been reported to deliver a significantly lower effective radiation dose than analogous imaging isotopes like 201Tl and 99 mTc sestamibi. High-quality β -decay data are essential to accurately appraise the total dose received by the patients. A source of 82Sr was produced at the Brookhaven Linac Isotope Producer (BLIP), transported to Argonne National Laboratory, and studied with the Gammasphere facility. Significant revisions have been made to the level scheme of 82Kr including 12 new levels, 50 new γ -ray transitions, and the determination of many new spin assignments through angular correlations. These new high-quality data allow a precise reappraisal of the β -decay strength function and thus the consequent dose received by patients.

Proceedings of the study of environmental change using isotope techniques

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-10-01

Global warming is acknowledged as a major crisis facing society today, principally due to anticipated impacts on the environment, and availability and distribution of water resources. Scientific understanding of recent human-induced climate change, as well as evaluation of potential mitigation strategies, is progressively being developed through studies of atmospheric greenhouse gases and modern water energy carbon cycling processes. These efforts have been advanced through study of past global climate changes to understand mechanisms that play a role in determining natural climate fluctuations observed in ice cores, lake and sea sediments, corals, paleo-groundwater, cave deposits, tree rings, and other archives. Predictive models incorporating natural and human-induced climate change processes contribute to a better appreciation for the sensitivity of climate to specific anthropogenic perturbations. Increasingly, isotopes are being integrated in climate change studies. For example, isotope methodologies offer substantial improvements in the ability to label the origin and fate of greenhouse gases, and for studying the water and carbon cycle response to past climate changes, a high priority area for action identified by the Intergovernmental Panel on Climate Change (IPCC). Isotopes are also widely used as diagnostic variables for validation of models aimed at providing a prognosis of future environmental conditions. The International Atomic Energy Agency (IAEA) has long supported research and development of isotope applications for climate studies. The joint IAEA/WMO Global Network for Isotopes in Precipitation managed by the IAEA has for the last four decades provided the basic isotope data necessary for integrating stable oxygen and hydrogen isotopes in climate models. The IAEA has also sponsored co-ordinated research projects on Isotope Variations of Carbon Dioxide and other Trace Gases in the Atmosphere and Isotope-Aided Studies of Atmospheric Carbon Dioxide

Proceedings of the study of environmental change using isotope techniques

International Nuclear Information System (INIS)

2002-01-01

Global warming is acknowledged as a major crisis facing society today, principally due to anticipated impacts on the environment, and availability and distribution of water resources. Scientific understanding of recent human-induced climate change, as well as evaluation of potential mitigation strategies, is progressively being developed through studies of atmospheric greenhouse gases and modern water energy carbon cycling processes. These efforts have been advanced through study of past global climate changes to understand mechanisms that play a role in determining natural climate fluctuations observed in ice cores, lake and sea sediments, corals, paleo-groundwater, cave deposits, tree rings, and other archives. Predictive models incorporating natural and human-induced climate change processes contribute to a better appreciation for the sensitivity of climate to specific anthropogenic perturbations. Increasingly, isotopes are being integrated in climate change studies. For example, isotope methodologies offer substantial improvements in the ability to label the origin and fate of greenhouse gases, and for studying the water and carbon cycle response to past climate changes, a high priority area for action identified by the Intergovernmental Panel on Climate Change (IPCC). Isotopes are also widely used as diagnostic variables for validation of models aimed at providing a prognosis of future environmental conditions. The International Atomic Energy Agency (IAEA) has long supported research and development of isotope applications for climate studies. The joint IAEA/WMO Global Network for Isotopes in Precipitation managed by the IAEA has for the last four decades provided the basic isotope data necessary for integrating stable oxygen and hydrogen isotopes in climate models. The IAEA has also sponsored co-ordinated research projects on Isotope Variations of Carbon Dioxide and other Trace Gases in the Atmosphere and Isotope-Aided Studies of Atmospheric Carbon Dioxide

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

Modeling and Simulation of a Gallium Nitride (GaN) Betavoltaic Energy Converter

Science.gov (United States)

2016-06-01

surrounding semiconductor by the ionization trail of beta particles . Fig. 2 shows an illustration of the DEC isotope battery. The advantage of using the...battery is enhanced lifetime because of the absence of semiconductor degradations from isotope due to low-energy beta particles . The configuration...betavoltaic process of EHP generation through a high-energy beta particle . The creation of phonons within the semiconductor is shown. This is covered

Evolution of triaxial shapes at large isospin: Rh isotopes

Directory of Open Access Journals (Sweden)

A. Navin

2017-04-01

Full Text Available The rotational response as a function of neutron–proton asymmetry for the very neutron-rich isotopes of Rh (116–119Rh has been obtained from the measurement of prompt γ rays from isotopically identified fragments, produced in fission reactions at energies around the Coulomb barrier. The measured energy “signature” splitting of the yrast bands, when compared with the Triaxial Projected Shell Model (TPSM calculations, shows the need for large, nearly constant, triaxial deformations. The present results are compared with global predictions for the existence of non axial shapes in the periodic table in the case of very neutron-rich nuclei Rh isotopes. The predicted trend of a second local maximum for a triaxial shape around N∼74 is not found.

Design and construction of a multi-layer CsI(Tl) telescope for high-energy reaction studies

International Nuclear Information System (INIS)

Yan, D.; Sun, Z.Y.; Yue, K.; Wang, S.T.; Zhang, X.H.; Yu, Y.H.; Chen, J.L.; Tang, S.W.; Fang, F.; Zhou, Y.; Sun, Y.; Wang, Z.M.; Sun, Y.Z.

2017-01-01

A prototype of a new CsI(Tl) telescope, which will be used in the reaction studies of light isotopes with energy of several hundred AMeV, was constructed and tested at the Institute of Modern Physics, Chinese Academy of Sciences. The telescope has a multi-layer structure, and the range information was obtained to improve the particle identification performance. This prototype has seven layers of different thickness. An energy resolution of 5.0% (FWHM) was obtained for one of the layers in a beam test experiment. Positive improvement for the identification of 14 O and 15 O isotopes was achieved using the range information.

Design and construction of a multi-layer CsI(Tl) telescope for high-energy reaction studies

Energy Technology Data Exchange (ETDEWEB)

Yan, D.; Sun, Z.Y. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yue, K., E-mail: yueke@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, S.T.; Zhang, X.H.; Yu, Y.H.; Chen, J.L.; Tang, S.W.; Fang, F. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhou, Y.; Sun, Y. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Lanzhou University, Lanzhou 730000 (China); Wang, Z.M.; Sun, Y.Z. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

2017-01-21

A prototype of a new CsI(Tl) telescope, which will be used in the reaction studies of light isotopes with energy of several hundred AMeV, was constructed and tested at the Institute of Modern Physics, Chinese Academy of Sciences. The telescope has a multi-layer structure, and the range information was obtained to improve the particle identification performance. This prototype has seven layers of different thickness. An energy resolution of 5.0% (FWHM) was obtained for one of the layers in a beam test experiment. Positive improvement for the identification of {sup 14}O and {sup 15}O isotopes was achieved using the range information.

Method and apparatus for isotope separation from a gas stream

International Nuclear Information System (INIS)

Szoke, A.

1978-01-01

A method and apparatus are described for isotope separation and in particular for separating the desired isotope from the gas in which it is contained by irradiating it with a laser. The laser selectively provides kinetic energy to the isotope through inelastic events, monomolecular or bimolecular, in order to cause it to segregate within or fly out of the gas stream in which it is contained

Subsystem for control of isotope production with linear electron accelerator

CERN Document Server

Karasyov, S P; Uvarov, V L

2001-01-01

In this report the high-current LINAC subsystem for diagnostic and monitoring the basic technological parameters of isotope production (energy flux of Bremsstrahlung photons and absorbed doze in the target,target activity, temperature and consumption of water cooling the converter and target) is described.T he parallel printer port (LPT) of the personal computer is proposed to use as an interface with the measurement channels.

Subsystem for control of isotope production with linear electron accelerator

International Nuclear Information System (INIS)

Karasyov, S.P.; Pomatsalyuk, R.I.; Uvarov, V.L.

2001-01-01

In this report the high-current LINAC subsystem for diagnostic and monitoring the basic technological parameters of isotope production (energy flux of Bremsstrahlung photons and absorbed doze in the target,target activity, temperature and consumption of water cooling the converter and target) is described.T he parallel printer port (LPT) of the personal computer is proposed to use as an interface with the measurement channels

Process and device for the excitation and selective dissociation by absorption of a laser light and application to isotopic enrichment

International Nuclear Information System (INIS)

Rigny, Paul.

1975-01-01

The description is given of a process for the excitation and selective dissociation by absorption of the monochromatic light emitted by a high power laser. The laser light at frequency ν 1 is beamed on to an isotopic mixture of gaseous molecules, some of these molecules presenting transitions, between two vibration levels corresponding to a given isotope, separated by an energy interval ΔE 1 =2h ν 1 , and the molecules of a given isotopic species are thus preferentially dissociated into several component parts [fr

High resolution laser spectroscopy of radioactive isotopes using a RFQ cooler-buncher at CERN-ISOLDE

CERN Document Server

Mané, E

2009-01-01

At CERN, the European Organization for Nuclear Research, radioactive nuclear beams are produced at the On-Line Isotope Mass Separator facility, ISOLDE. This facility provides a variety of exotic nuclear species for multidisciplinary experiments including nuclear physics. A gas-filled linear Paul trap was commissioned off-line and on-line and now is fully integrated at the focal plane of the high resolution separator magnets of ISOLDE. Ion beams with reduced transverse emitance and energy spread are now available for all experiments located downstream the separator beam line. This device is also able to accumulate the ion beam and release the collected sample in short bunches. Typical accumulation times are 100 ms and the released bunch width is 5-20 $\\mu{s}$. Such bunching capabilities has substantially increased the sensitivity of collinear laser spectroscopy with fluorescence detection by reducing the background from laser scatter by up to four orders of magnitude. The spectroscopic quadrupole moments of $^...

Process chemistry related to hydrogen isotopes

International Nuclear Information System (INIS)

Iwasaki, Matae; Ogata, Yukio

1991-01-01

Hydrogen isotopes, that is, protium, deuterium and tritium, are all related deeply to energy in engineering region. Deuterium and tritium exist usually as water in extremely thin state. Accordingly, the improvement of the technology for separating these isotopes is a large engineering subject. Further, tritium is radioactive and its half-life period is 12.26 years, therefore, it is desirable to fix it in more stable form besides its confinement in the handling system. As the chemical forms of hydrogen, the molecular hydrogen with highest reactivity, metal hydride, carbon-hydrogen-halogen system compounds, various inorganic hydrides, most stable water and hydroxides are enumerated. The grasping of the behavior from reaction to stable state of these hydrogen compounds and the related materials is the base of process chemistry. The reaction of exchanging isotopes between water and hydrogen on solid catalyzers, the decomposition of ethane halide containing hydrogen, the behavior of water and hydroxides in silicates are reported. The isotope exchange between water and hydrogen is expected to be developed as the process of separating and concentrating hydrogen isotopes. (K.I.) 103 refs

High energy neutron radiography

International Nuclear Information System (INIS)

Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

1996-01-01

High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

Isotope hydrology: applied discipline in earth sciences

International Nuclear Information System (INIS)

Froehlich, K.; Rozanski, K.; Araguas Araguas, L.

1998-01-01

The discipline 'isotope hydrology' is being reviewed from the perspective of the Isotope Hydrology Section of the International Atomic Energy Agency in Vienna. The Section was created in the late fifties and is activities involved int the scientific progress of the discipline. The role of the IAEA in the development of isotope hydrology has always been of a dual nature: on one hand, the Section has been and still is heavily engaged in supporting and coordinating further development of isotope methodologies, on the other hand, it serves as an interface between the methodological development in research institutes and the applied work using proven techniques in field projects on water resources assessment and management. The paper provides a brief overview of applications of isotope-based methodologies in hydrology, with emphasis on new trends and challenges related to man's growing impact on the water cycle. This contribution is a tribute to the memory of the former Head of the Isotope Hydrology Section, Jean-Charles Fontes, to whom we owe so much. (authors)

Metabolic studies in man using stable isotopes

International Nuclear Information System (INIS)

Faust, H.; Jung, K.; Krumbiegel, P.

1993-01-01

In this project, stable isotope compounds and stable isotope pharmaceuticals were used (with emphasis on the application of 15 N) to study several aspects of nitrogen metabolism in man. Of the many methods available, the 15 N stable isotope tracer technique holds a special position because the methodology for application and nitrogen isotope analysis is proven and reliable. Valid routine methods using 15 N analysis by emission spectrometry have been demonstrated. Several methods for the preparation of biological material were developed during our participation in the Coordinated Research Programme. In these studies, direct procedures (i.e. use of diluted urine as a samples without chemical preparation) or rapid isolation methods were favoured. Within the scope of the Analytical Quality Control Service (AQCS) enriched stable isotope reference materials for medical and biological studies were prepared and are now available through the International Atomic Energy Agency. The materials are of special importance as the increasing application of stable isotopes as tracers in medical, biological and agricultural studies has focused interest on reliable measurements of biological material of different origin. 24 refs

Dynamical and many-body correlation effects in the kinetic energy spectra of isotopes produced in nuclear multifragmentation

Science.gov (United States)

Souza, S. R.; Donangelo, R.; Lynch, W. G.; Tsang, M. B.

2018-03-01

The properties of the kinetic energy spectra of light isotopes produced in the breakup of a nuclear source and during the de-excitation of its products are examined. The initial stage, at which the hot fragments are created, is modeled by the statistical multifragmentation model, whereas the Weisskopf-Ewing evaporation treatment is adopted to describe the subsequent fragment de-excitation, as they follow their classical trajectories dictated by the Coulomb repulsion among them. The energy spectra obtained are compared to available experimental data. The influence of the fusion cross section entering into the evaporation treatment is investigated and its influence on the qualitative aspects of the energy spectra turns out to be small. Although these aspects can be fairly well described by the model, the underlying physics associated with the quantitative discrepancies remains to be understood.

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

Pathways of coupled arsenic and iron cycling in high arsenic groundwater of the Hetao basin, Inner Mongolia, China: an iron isotope approach

Science.gov (United States)

Guo, Huaming; Liu, Chen; Lu, Hai; Wanty, Richard B.; Wang, Jun; Zhou, Yinzhu

2013-01-01

High As groundwater is widely distributed all over the world, which has posed a significant health impact on millions of people. Iron isotopes have recently been used to characterize Fe cycling in aqueous environments, but there is no information on Fe isotope characteristics in the groundwater. Since groundwater As behavior is closely associated with Fe cycling in the aquifers, Fe isotope signatures may help to characterize geochemical processes controlling As concentrations of shallow groundwaters. This study provides the first observation of Fe isotope fractionation in high As groundwater and evaluation of Fe cycling and As behaviors in shallow aquifers in terms of Fe isotope signatures. Thirty groundwater samples were taken for chemical and isotopic analysis in the Hetao basin, Inner Mongolia. Thirty-two sediments were sampled as well from shallow aquifers for Fe isotope analysis. Results showed that groundwater was normally enriched in isotopically light Fe with δ56Fe values between −3.40‰ and 0.58‰ and median of −1.14‰, while heavier δ56Fe values were observed in the sediments (between −1.10‰ and 0.75‰, median +0.36‰). In reducing conditions, groundwaters generally had higher δ56Fe values, in comparison with oxic conditions. High As groundwaters, generally occurring in reducing conditions, had high δ56Fe values, while low As groundwaters normally had low δ56Fe values. Although sediment δ56Fe values were generally independent of lithological conditions, a large variation in sediment δ56Fe values was observed in the oxidation–reduction transition zone. Three pathways were identified for Fe cycling in shallow groundwater, including dissimilatory reduction of Fe(III) oxides, re-adsorption of Fe(II), and precipitation of pyrite and siderite. Dissimilatory reduction of Fe(III) oxides resulted in light δ56Fe values (around −1.0‰) and high As concentration (>50 μg/L) in groundwater in anoxic conditions. Re-adsorption of isotopically

Experimental study of the higher isotopes of plutonium in the coupled fast-thermal assembly Ermine

International Nuclear Information System (INIS)

Bioux, Philippe.

1973-01-01

The most important results so far of the plutonium isotopes programme carried out in Ermine are reviewed. The results were obtained on four networks: one with uranium fuel and three with plutonium. The choice of these four networks was essentially based on the energy range of their nuclear reactions, wide enough to include the large reactor energy range, and yet realistic, with a neutron energy distribution in the 4 networks which is never very far from that encountered in a power reactor. The information relative to the high isotopes of plutonium which were obtained in these networks mostly came from: the fission indices measured in the 4 networks, the study of the balance in the two media at k(infinite)=1, reactivity measurements on cell replacements and on various plutonium samples, carried out on the three plutonium fuel networks [fr

Operating manual for the High Flux Isotope Reactor. Volume I. Description of the facility

Energy Technology Data Exchange (ETDEWEB)

1982-09-01

This volume contains a comprehensive description of the High Flux Isotope Reactor Facility. Its primary purpose is to supplement the detailed operating procedures, providing the reactor operators with background information on the various HFIR systems. The detailed operating procdures are presented in another report.

Operating manual for the High Flux Isotope Reactor. Volume I. Description of the facility

International Nuclear Information System (INIS)

1982-09-01

This volume contains a comprehensive description of the High Flux Isotope Reactor Facility. Its primary purpose is to supplement the detailed operating procedures, providing the reactor operators with background information on the various HFIR systems. The detailed operating procdures are presented in another report

Sm isotope composition and Sm/Eu ratio determination in an irradiated 153Eu sample by ion exchange chromatography-quadrupole inductively coupled plasma mass spectrometry combined with double spike isotope dilution technique

International Nuclear Information System (INIS)

Bourgeois, M.; Isnard, H.; Gourgiotis, A.; Stadelmann, G.; Gautier, C.; Mialle, S.; Nonell, A.; Chartier, F.

2011-01-01

Within the framework of the research undertaken by the French Atomic Energy Commission on transmutation of long-lived radionuclides, targets of highly enriched actinides and fission products were irradiated in the fast neutron reactor Phenix. Precise and accurate measurements of the isotopic and elemental composition of the enriched elements are therefore required. In order to obtain the uncertainties of several per mil and to reduce handling time and exposure to analyst on radioactive material, the on-line coupling of ion exchange chromatography with quadrupole inductively coupled plasma mass spectrometry has been associated with the technique of the double spike isotope dilution. We present in this paper the results obtained on an irradiated sample of Europium oxide powder (enriched at 99.13% in 153 Eu). After irradiation of around 5 mg of Eu 2 O 3 powder the theoretical calculations predict the formation of several micrograms of gadolinium and samarium isotopes. In relation to the very high activity of the sample after irradiation and the very low quantity of Sm formed, the on-line ion exchange chromatography separation of Gd, Sm and Eu before Sm isotope ratio measurements has been developed for the quantification of the 152 Sm/ 153 Eu ratio. These on-line measurements were associated with the double spike isotope dilution technique after calibration of a 147 Sm/ 151 Eu spike solution. The external reproducibility of Sm isotopic ratios was determined to be around 0.5% (2 σ) resulting in a final uncertainty on the 152 Sm/ 153 Eu ratio of around 1% (2 σ). These on-line measurements present therefore a robust and high-throughput alternative to the thermal-ionisation mass spectrometry technique used so far in combination with off-line chromatographic separation, particularly in nuclear applications where characterisation of high activity sample solutions is required. (authors)

High-precision optical measurements of 13C/12C isotope ratios in organic compounds at natural abundance

Science.gov (United States)

Zare, Richard N.; Kuramoto, Douglas S.; Haase, Christa; Tan, Sze M.; Crosson, Eric R.; Saad, Nabil M. R.

2009-01-01

A continuous-flow cavity ring-down spectroscopy (CRDS) system integrating a chromatographic separation technique, a catalytic combustor, and an isotopic 13C/12C optical analyzer is described for the isotopic analysis of a mixture of organic compounds. A demonstration of its potential is made for the geochemically important class of short-chain hydrocarbons. The system proved to be linear over a 3-fold injection volume dynamic range with an average precision of 0.95‰ and 0.67‰ for ethane and propane, respectively. The calibrated accuracy for methane, ethane, and propane is within 3‰ of the values determined using isotope ratio mass spectrometry (IRMS), which is the current method of choice for compound-specific isotope analysis. With anticipated improvements, the low-cost, portable, and easy-to-use CRDS-based instrumental setup is poised to evolve into a credible challenge to the high-cost and complex IRMS-based technique. PMID:19564619

Computer study of isotope production for medical and industrial applications in high power accelerators

Science.gov (United States)

Mashnik, S. G.; Wilson, W. B.; Van Riper, K. A.

2001-07-01

Methods for radionuclide production calculation in a high power proton accelerator have been developed and applied to study production of 22 isotopes. These methods are readily applicable both to accelerator and reactor environments and to the production of other radioactive and stable isotopes. We have also developed methods for evaluating cross sections from a wide variety of sources into a single cross section set and have produced an evaluated library covering about a third of all natural elements that may be expanded to other reactions. A 684 page detailed report on this study, with 37 tables and 264 color figures, is available on the Web at http://t2.lanl.gov/publications/.

Isotope analysis of diamond-surface passivation effect of high-temperature H2O-grown atomic layer deposition-Al2O3 films

International Nuclear Information System (INIS)

Hiraiwa, Atsushi; Saito, Tatsuya; Matsumura, Daisuke; Kawarada, Hiroshi

2015-01-01

The Al 2 O 3 film formed using an atomic layer deposition (ALD) method with trimethylaluminum as Al precursor and H 2 O as oxidant at a high temperature (450 °C) effectively passivates the p-type surface conduction (SC) layer specific to a hydrogen-terminated diamond surface, leading to a successful operation of diamond SC field-effect transistors at 400 °C. In order to investigate this excellent passivation effect, we carried out an isotope analysis using D 2 O instead of H 2 O in the ALD and found that the Al 2 O 3 film formed at a conventional temperature (100 °C) incorporates 50 times more CH 3 groups than the high-temperature film. This CH 3 is supposed to dissociate from the film when heated afterwards at a higher temperature (550 °C) and causes peeling patterns on the H-terminated surface. The high-temperature film is free from this problem and has the largest mass density and dielectric constant among those investigated in this study. The isotope analysis also unveiled a relatively active H-exchange reaction between the diamond H-termination and H 2 O oxidant during the high-temperature ALD, the SC still being kept intact. This dynamic and yet steady H termination is realized by the suppressed oxidation due to the endothermic reaction with H 2 O. Additionally, we not only observed the kinetic isotope effect in the form of reduced growth rate of D 2 O-oxidant ALD but found that the mass density and dielectric constant of D 2 O-grown Al 2 O 3 films are smaller than those of H 2 O-grown films. This is a new type of isotope effect, which is not caused by the presence of isotopes in the films unlike the traditional isotope effects that originate from the presence of isotopes itself. Hence, the high-temperature ALD is very effective in forming Al 2 O 3 films as a passivation and/or gate-insulation layer of high-temperature-operation diamond SC devices, and the knowledge of the aforementioned new isotope effect will be a basis for further enhancing ALD

A method of uranium isotopes concentration analysis

International Nuclear Information System (INIS)

Lin Yuangen; Jiang Meng; Wu Changli; Duan Zhanyuan; Guo Chunying

2010-01-01

A basic method of uranium isotopes concentration is described in this paper. The iteration method is used to calculate the relative efficiency curve, by analyzing the characteristic γ energy spectrum of 235 U, 232 U and the daughter nuclide of 238 U, then the relative activity can be calculated, at last the uranium isotopes concentration can be worked out, and the result is validated by the experimentation. (authors)

Uranium isotopic ratio measurements ({sup 235}U/{sup 238}U) by laser ablation high resolution inductively coupled plasma mass spectrometry for environmental radioactivity monitoring - {sup 235}U/{sup 238}U isotope ratio analysis by LA-ICP-MS-HR for environmental radioactivity monitoring

Energy Technology Data Exchange (ETDEWEB)

David, K.; Mokili, M.B.; Rousseau, G.; Deniau, I.; Landesman, C. [SUBATECH, Ecole des Mines de Nantes, Universite de Nantes, CNRS/IN2P3, 4 rue Alfred Kastler, 44307 Nantes cedex 3 (France)

2014-07-01

The protection of the aquatic and terrestrial environments from a broad range of contaminants spread by nuclear activities (nuclear plants, weapon tests or mining) require continuous monitoring of long-lives radionuclides that were released into the environment. The precise determination of uranium isotope ratios in both natural and potential contaminated samples is of primary concern for the nuclear safeguards and the control of environmental contamination. As an example, analysis of environmental samples around nuclear plants are carried out to detect the traces in the environment originating from nuclear technology activities. This study deals with the direct analysis of {sup 235}U/{sup 238}U isotope ratios in real environmental solid samples performed with laser ablation (LA)-HR-ICP-MS. A similar technique has already been reported for the analysis of biological samples or uranium oxide particles [1,2] but to our knowledge, this was never applied on real environmental samples. The high sensitivity, rapid acquisition time and low detection limits are the main advantages of high resolution ICP-MS for accurate and precise isotope ratio measurements of uranium at trace and ultra-trace levels. In addition, the use of laser ablation allows the analysis of solid samples with minimal preparation. A a consequence, this technique is very attractive for conducting rapid direct {sup 235}U/{sup 238}U isotope ratio analysis on a large set of various matrix samples likely to be encountered in environmental monitoring such as corals, soils, sands, sediments, terrestrial and marine bio-indicators. For the present study, LA-ICP-MS-HR analyses are performed using a New Wave UP213 nano-second Nd:YAG laser coupled to a Thermo Element-XR high resolution mass spectrometer. Powdered samples are compacted with an hydraulic press (5 tons) in order to obtain disk-shaped pellet (10-13 mm in diameter and 2 mm in thickness). The NIST612 reference glass is used for LA-ICP-MS-HR tuning and as

Short-lived radionuclides produced on the ORNL 86-inch cyclotron and High-Flux Isotope Reactor

International Nuclear Information System (INIS)

Lamb, E.

1985-01-01

The production of short-lived radionuclides at ORNL includes the preparation of target materials, irradiation on the 86-in. cyclotron and in the High Flux Isotope Reactor (HFIR), and chemical processing to recover and purify the product radionuclides. In some cases the target materials are highly enriched stable isotopes separated on the ORNL calutrons. High-purity 123 I has been produced on the 86-in. cyclotron by irradiating an enriched target of 123 Te in a proton beam. Research on calutron separations has led to a 123 Te product with lower concentrations of 124 Te and 126 Te and, consequently to lower concentrations of the unwanted radionuclides, 124 I and 126 I, in the 123 I product. The 86-in. cyclotron accelerates a beam of protons only but is unique in providing the highest available beam current of 1500 μA at 21 MeV. This beam current produces relatively large quantities of radionuclides such as 123 I and 67 Ga

Rare Isotopes Physics in the Multimessenger Era

Science.gov (United States)

Schatz, Hendrik

2018-06-01

While these isotopes only exist for fractions of seconds, their properties shape the resulting cosmic distribution of elements and the astronomical observables including spectra, neutrinos, and gravitational waves. The long standing challenge in nuclear astrophysics of the production of the relevant isotopes in the laboratory is now overcome with a new generation of rare isotope accelerator facilities now coming online. One example is the FRIB facility under construction at Michigan State University for the US Department of Energy, Office of Science, Office of Nuclear Physics. These new capabilities in nuclear physics coincide with advances in astronomy directly related to the cosmic sites where these isotopes are created, in particular in time domain and gravitational wave astronomy. I will discuss the importance of rare isotope physics in interpreting multi-messenger observations and how advances in nuclear physics and astronomy when combined promise to lead us towards a comprehensive theory of the origin of the elements.

Structure of Li, Be And B isotopes studied with quantum molecular dynamic model

International Nuclear Information System (INIS)

Abdel-Hafiez, A.; Saleh, Z.A.

2000-01-01

Quantum molecular dynamics (QMD) is applied to study the ground state properties of Li, Be and B isotopes. The model Hamiltonian includes both two-and three-body density dependent interactions, a Coulomb term, and a momentum dependent Pauli potential. With parameters which guarantee the infinite nuclear matter properties, the QMD model can only reproduce the binding energies for Be and B isotopes. The experimental root mean square radii of the Li, Be and B isotopes are not sufficiently reproduced by these parameters. It is shown, however, that the binding energies and root mean square radii of these isotopes can simultaneously be reproduced in the lower density limit of the potential parameters

A post-accelerator for the US rare isotope accelerator facility

CERN Document Server

Ostroumov, P N; Kolomiets, A A; Nolen, J A; Portillo, M; Shepard, K W; Vinogradov, N E

2003-01-01

The proposed rare isotope accelerator (RIA) facility includes a post-accelerator for rare isotopes (RIB linac) which must produce high-quality beams of radioactive ions over the full mass range, including uranium, at energies above the Coulomb barrier, and have high transmission and efficiency. The latter requires the RIB linac to accept at injection ions in the 1+ charge state. A concept for such a post accelerator suitable for ions up to mass 132 has been previously described . This paper presents a modified concept which extends the mass range to uranium. A high resolution separator for purifying beams at the isobaric level precedes the RIB linac. The mass filtering process will provide high purity beams while preserving transmission. For most cases a resolution of about m/DELTA m=20 000 is adequate at mass A=100 to obtain a separation between isobars of mass excess difference of 5 MeV. The design for a device capable of purifying beams at the isobaric level includes calculations up to fifth order. The RIB...

Positron range in PET imaging: non-conventional isotopes

International Nuclear Information System (INIS)

Jødal, L; Le Loirec, C; Champion, C

2014-01-01

In addition to conventional short-lived radionuclides, longer-lived isotopes are becoming increasingly important to positron emission tomography (PET). The longer half-life both allows for circumvention of the in-house production of radionuclides, and expands the spectrum of physiological processes amenable to PET imaging, including processes with prohibitively slow kinetics for investigation with short-lived radiotracers. However, many of these radionuclides emit ‘high-energy’ positrons and gamma rays which affect the spatial resolution and quantitative accuracy of PET images. The objective of the present work is to investigate the positron range distribution for some of these long-lived isotopes. Based on existing Monte Carlo simulations of positron interactions in water, the probability distribution of the line of response displacement have been empirically described by means of analytic displacement functions. Relevant distributions have been derived for the isotopes 22 Na, 52 Mn, 89 Zr, 45 Ti, 51 Mn, 94m Tc, 52m Mn, 38 K, 64 Cu, 86 Y, 124 I, and 120 I. It was found that the distribution functions previously found for a series of conventional isotopes (Jødal et al 2012 Phys. Med. Bio. 57 3931–43), were also applicable to these non-conventional isotopes, except that for 120 I, 124 I, 89 Zr, 52 Mn, and 64 Cu, parameters in the formulae were less well predicted by mean positron energy alone. Both conventional and non-conventional range distributions can be described by relatively simple analytic expressions. The results will be applicable to image-reconstruction software to improve the resolution. (paper)

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.

Strontium isotope evidence for a highly mobile population on the Pamir Plateau 2500 years ago

Science.gov (United States)

Wang, Xueye; Tang, Zihua; Wu, Jing; Wu, Xinhua; Wu, Yiqun; Zhou, Xinying

2016-10-01

Archeological researches have proposed arguments for human mobility and long-distance trading over the Eurasia before the Silk Roads. Here we utilize biologically available strontium isotope analysis to assess the extent of pre-Silk Road population movements and cultural communications across the Asian interior. From an early Iron Age cemetery (ca. 2500 yr B.P.) on the eastern Pamir Plateau, mean 87Sr/86Sr ratios from 34 individuals display considerable isotopic variability, and 10 individuals are distinguished as migrants based on the local strontium isotope range of 0.710296-0.710572 defined by 12 ovicaprine bones. Comparison of the proportion (10/34) with the regional census data completed in 1909 A.D. (3% non-locals) suggests a highly migratory behavior on the plateau 2500 years ago. Furthermore, exotic mortuary objects, such as silk fabrics from eastern China and angular harp originated from the Near East, clearly demonstrate an interaction between different cultures on the plateau before the establishment of the Silk Road.

Calculations of nuclear energies using the energy density formalism

International Nuclear Information System (INIS)

Pu, W.W.T.

1975-01-01

The energy density formalism (EDF) is used to investigate two problems. In this formalism the energy of the nucleus is expressed as a functional of its density. The nucleus energy is obtained by minimizing the functional with respect to the density. The first problem has to do with the stability of nuclei having shapes of different degrees of central depression (bubble shapes). It is shown that the bubble shapes are energetically favorable only for unrealistically large nuclei. Particularly, the super heavy nucleus that has been suggested (Z = 114, N = 184) prefers a shape with constant central density. These results are in good agreement with earlier calculations using the liquid drop model. The second problem concerns an anomaly detected experimentally in the isotope shift of mercury. The isotope shifts among a long chain of mercury isotopes show a sudden change as the neutron number is reduced. In particular, the experimental result suggests that the effective size of the charge distributions of 183 Hg and 185 Hg are as large as that of 196 Hg. Such sudden changes in other nuclei have been attributed to a sudden onset of permanent quadruple deformation. In the case of mercury there is no experimental evidence for deformed shapes. It was, therefore, suggested that the proton distribution might develop a central depression in the lighter isotopes. The EDF is used to investigate the mercury isotope shift anomaly following the aforementioned suggestion. Specifically, nucleon densities with different degrees of central depression are generated. Energies corresponding to these densities are obtained. To allow for shell effects, nucleon densities are obtained from single-particle wave functions. Calculations are made for a few mercury isotopes, especially for 184 Hg. The results are that in all cases the energy is lower for densities corresponding to a solid spherical shape

Design and development of high-resolution atomic beam fluorescence spectroscopy facility for isotope shift and hyperfine structure measurements

International Nuclear Information System (INIS)

Acharyulu, G.V.S.G.; Sankari, M.; Kiran Kumar, P.V.; Suryanarayana, M.V.

2012-01-01

A high-resolution atomic beam fluorescence spectroscopy facility for the determination of isotope shifts and hyperfine structure in atomic species has been designed and developed. A resistively heated graphite tube atomic beam source was designed, tested and integrated into a compact interaction chamber for atomic beam fluorescence experiments. The design of the laser-atom interaction chamber and the source has been modified in a phased manner so as to achieve sub-Doppler resolution. The system has been used to record the hyperfine spectrum of the D2 transitions of Rb and K isotopes. The spectral resolution achieved is ∼ 26 MHz and is adequate to carry out high resolution measurement of isotope shifts and hyperfine structure of various atomic species. The other major advantage of the source is that it requires very small amounts of sample for achieving very good signal to noise ratio. (author)

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

NARCIS (Netherlands)

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

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to

High to ultra-high power electrical energy storage.

Science.gov (United States)

Sherrill, Stefanie A; Banerjee, Parag; Rubloff, Gary W; Lee, Sang Bok

2011-12-14

High power electrical energy storage systems are becoming critical devices for advanced energy storage technology. This is true in part due to their high rate capabilities and moderate energy densities which allow them to capture power efficiently from evanescent, renewable energy sources. High power systems include both electrochemical capacitors and electrostatic capacitors. These devices have fast charging and discharging rates, supplying energy within seconds or less. Recent research has focused on increasing power and energy density of the devices using advanced materials and novel architectural design. An increase in understanding of structure-property relationships in nanomaterials and interfaces and the ability to control nanostructures precisely has led to an immense improvement in the performance characteristics of these devices. In this review, we discuss the recent advances for both electrochemical and electrostatic capacitors as high power electrical energy storage systems, and propose directions and challenges for the future. We asses the opportunities in nanostructure-based high power electrical energy storage devices and include electrochemical and electrostatic capacitors for their potential to open the door to a new regime of power energy.

Neutron scattering at the high-flux isotope reactor

International Nuclear Information System (INIS)

Cable, J.W. Chakoumakos, B.C.; Dai, P.

1995-01-01

The title facilities offer the brightest source of neutrons in the national user program. Neutron scattering experiments probe the structure and dynamics of materials in unique and complementary ways as compared to x-ray scattering methods and provide fundamental data on materials of interest to solid state physicists, chemists, biologists, polymer scientists, colloid scientists, mineralogists, and metallurgists. Instrumentation at the High- Flux Isotope Reactor includes triple-axis spectrometers for inelastic scattering experiments, a single-crystal four diffractometer for crystal structural studies, a high-resolution powder diffractometer for nuclear and magnetic structure studies, a wide-angle diffractometer for dynamic powder studies and measurements of diffuse scattering in crystals, a small-angle neutron scattering (SANS) instrument used primarily to study structure-function relationships in polymers and biological macromolecules, a neutron reflectometer for studies of surface and thin-film structures, and residual stress instrumentation for determining macro- and micro-stresses in structural metals and ceramics. Research highlights of these areas will illustrate the current state of neutron science to study the physical properties of materials

Comparison of different methods of determining plutonium content and isotopic composition

International Nuclear Information System (INIS)

Dowell, M.R.W.

1985-05-01

At Rockwell Hanford Operations, several different methods are used to determine plutonium content and isotopic composition. These include alpha particle energy analysis, calorimetry/gamma-ray analysis, mass spectrometry, and low energy ray assay. Each is used in a process control environment and has its advantages and disadvantages in terms of sample matrix, sample preparation, concentration, error ranges, detection limits, and turn around time. Of the methods discussed, special attention is paid to the Plutonium Isotopics Solution Counter, a low energy gamma ray assay system designed to provide plutonium and americium content and isotopic composition of Pu-238 through Pu-241 and Am-241. It is qualitatively and quantitatively compared to the other methods. A brief description of sample types which the Solution Counter analyzes is presented. 4 refs., 4 tabs

Hydroponic isotope labeling of entire plants and high-performance mass spectrometry for quantitative plant proteomics.

Science.gov (United States)

Bindschedler, Laurence V; Mills, Davinia J S; Cramer, Rainer

2012-01-01

Hydroponic isotope labeling of entire plants (HILEP) combines hydroponic plant cultivation and metabolic labeling with stable isotopes using (15)N-containing inorganic salts to label whole and mature plants. Employing (15)N salts as the sole nitrogen source for HILEP leads to the production of healthy-looking plants which contain (15)N proteins labeled to nearly 100%. Therefore, HILEP is suitable for quantitative plant proteomic analysis, where plants are grown in either (14)N- or (15)N-hydroponic media and pooled when the biological samples are collected for relative proteome quantitation. The pooled (14)N-/(15)N-protein extracts can be fractionated in any suitable way and digested with a protease for shotgun proteomics, using typically reverse phase liquid chromatography nanoelectrospray ionization tandem mass spectrometry (RPLC-nESI-MS/MS). Best results were obtained with a hybrid ion trap/FT-MS mass spectrometer, combining high mass accuracy and sensitivity for the MS data acquisition with speed and high-throughput MS/MS data acquisition, increasing the number of proteins identified and quantified and improving protein quantitation. Peak processing and picking from raw MS data files, protein identification, and quantitation were performed in a highly automated way using integrated MS data analysis software with minimum manual intervention, thus easing the analytical workflow. In this methodology paper, we describe how to grow Arabidopsis plants hydroponically for isotope labeling using (15)N salts and how to quantitate the resulting proteomes using a convenient workflow that does not require extensive bioinformatics skills.

Isotopic equilibria between sulphur solute species at high temperature

International Nuclear Information System (INIS)

Robinson, B.W.

1978-01-01

Sulphur solute species in ore solutions and geothermal discharges include HSO 4 - , SO 4 2- , H 2 S, and HS - , as well as the ion-paired species, NaHS 0 , NaHSO 4 - and Na 2 SO 4 0 . Observed sulphate-sulphide fractionation factors and the rates of attainment of isotopic equilibrium are likely to depend on the nature of the sulphur species actually taking part in these isotopic equilibria. Preliminary experiments in alkaline solution (pH 10.1 at 20 0 C) were carried out in a gold cell. No significant isotope fractionation was observed between the SO 4 2- and HS - in 29 days at 200 0 C, 63days at 300 0 C, or 90 days at 250 0 C. However, similar experiments at 350 0 C in sealed gold capsules at room temperature pH 8.5 showed slow exchange(t( 1 / 2 ) was calculated to be 510 days for the SO 4 2- -HS - exchange reaction using the theoretical fractionation of 20.2 0 / 00 ). The addition of NaCl appeared to have no affect on the exchange. However, pH strongly controls the reaction rate, and exchange probably involves H 2 S and the HSO 4 - ion. Additional preliminary experiments were conducted with a fivefold increase in the sulphur concentration; a decrease in t( 1 / 2 ) to 142 days resulted. Some inter-relationship between sulphur concentration and exchange rate thus exists. The important controlling parameters of isotope exchange (temperature, pH, and ΣS) can be seen to have influenced exchange in natural systems.(auth.)

High-energy detector

Science.gov (United States)

Bolotnikov, Aleksey E [South Setauket, NY; Camarda, Giuseppe [Farmingville, NY; Cui, Yonggang [Upton, NY; James, Ralph B [Ridge, NY

2011-11-22

The preferred embodiments are directed to a high-energy detector that is electrically shielded using an anode, a cathode, and a conducting shield to substantially reduce or eliminate electrically unshielded area. The anode and the cathode are disposed at opposite ends of the detector and the conducting shield substantially surrounds at least a portion of the longitudinal surface of the detector. The conducting shield extends longitudinally to the anode end of the detector and substantially surrounds at least a portion of the detector. Signals read from one or more of the anode, cathode, and conducting shield can be used to determine the number of electrons that are liberated as a result of high-energy particles impinge on the detector. A correction technique can be implemented to correct for liberated electron that become trapped to improve the energy resolution of the high-energy detectors disclosed herein.

Energy Systems High-Pressure Test Laboratory | Energy Systems Integration

Science.gov (United States)

Facility | NREL Energy Systems High-Pressure Test Laboratory Energy Systems High-Pressure Test Laboratory In the Energy Systems Integration Facility's High-Pressure Test Laboratory, researchers can safely test high-pressure hydrogen components. Photo of researchers running an experiment with a hydrogen fuel

Neutron spectra and dosimetric features of isotopic neutron sources: a review

Energy Technology Data Exchange (ETDEWEB)

Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Martinez O, S. A., E-mail: fermineutron@yahoo.com [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte 39-115, 150003 Tunja, Boyaca (Colombia)

2015-10-15

A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of {sup 24}NaBe, {sup 24}NaD{sub 2}O, {sup 116}InBe, {sup 140}LaBe, {sup 238}PuLi, {sup 239}PuBe, {sup 241}AmB, {sup 241}AmBe, {sup 241}AmF, {sup 241}AmLi, {sup 242}CmBe, {sup 210}PoBe, {sup 226}RaBe, {sup 252}Cf and {sup 252}Cf/D{sub 2}O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

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)

Medical isotope identification with large mobile detection systems

Science.gov (United States)

Mukhopadhyay, Sanjoy; Maurer, Richard

2012-10-01

The Remote Sensing laboratory (RSL) of National Security Technologies Inc. has built an array of large (5.08 - cm x 10.16 - cm x 40.6 - cm) thallium doped sodium iodide (NaI: Tl) scintillators to locate and screen gamma-ray emitting radioisotopes that are of interests to radiological emergency responders [1]. These vehicle mounted detectors provide the operators with rapid, simple, specific information for radiological threat assessment. Applications include large area inspection, customs inspection, border protection, emergency response, and monitoring of radiological facilities. These RSL mobile units are currently being upgraded to meet the Defense Threat Reduction Agency mission requirements for a next-generation system capable of detecting and identifying nuclear threat materials. One of the challenging problems faced by these gamma-ray detectors is the unambiguous identification of medical isotopes like 131I (364.49 keV [81.7%], 636.99 keV [7.17%]), 99Tcm (140.51 keV [89.1%]) and 67Ga (184.6 keV [19.7%], 300.2 [16.0%], 393.5 [4.5%] that are used in radionuclide therapy and often have overlapping gamma-ray energy regions of interest (ROI). The problem is made worse by short (about 5 seconds) acquisition time of the spectral data necessary for dynamic mobile detectors. This article describes attempts to identify medical isotopes from data collected from this mobile detection system in a short period of time (not exceeding 5 secs) and a large standoff distance (typically 10 meters) The mobile units offer identification capabilities that are based on hardware auto stabilization of the amplifier gain. The 1461 keV gamma-energy line from 40K is tracked. It uses gamma-ray energy windowing along with embedded mobile Gamma Detector Response and Analysis Software (GADRAS) [2] simultaneously to deconvolve any overlapping gamma-energy ROIs. These high sensitivity detectors are capable of resolving complex masking scenarios and exceed all ANSI N42.34 (2006) requirements

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.

On-line hydrogen-isotope measurements of organic samples using elemental chromium: An extension for high temperature elemental-analyzer techniques

Science.gov (United States)

Gehre, Matthias; Renpenning, Julian; Gilevska, Tetyana; Qi, Haiping; Coplen, Tyler B.; Meijer, Harro A.J.; Brand, Willi A.; Schimmelmann, Arndt

2015-01-01

The high temperature conversion (HTC) technique using an elemental analyzer with a glassy carbon tube and filling (temperature conversion/elemental analysis, TC/EA) is a widely used method for hydrogen isotopic analysis of water and many solid and liquid organic samples with analysis by isotope-ratio mass spectrometry (IRMS). However, the TC/EA IRMS method may produce inaccurate δ2H results, with values deviating by more than 20 mUr (milliurey = 0.001 = 1‰) from the true value for some materials. We show that a single-oven, chromium-filled elemental analyzer coupled to an IRMS substantially improves the measurement quality and reliability for hydrogen isotopic compositions of organic substances (Cr-EA method). Hot chromium maximizes the yield of molecular hydrogen in a helium carrier gas by irreversibly and quantitatively scavenging all reactive elements except hydrogen. In contrast, under TC/EA conditions, heteroelements like nitrogen or chlorine (and other halogens) can form hydrogen cyanide (HCN) or hydrogen chloride (HCl) and this can cause isotopic fractionation. The Cr-EA technique thus expands the analytical possibilities for on-line hydrogen-isotope measurements of organic samples significantly. This method yielded reproducibility values (1-sigma) for δ2H measurements on water and caffeine samples of better than 1.0 and 0.5 mUr, respectively. To overcome handling problems with water as the principal calibration anchor for hydrogen isotopic measurements, we have employed an effective and simple strategy using reference waters or other liquids sealed in silver-tube segments. These crimped silver tubes can be employed in both the Cr-EA and TC/EA techniques. They simplify considerably the normalization of hydrogen-isotope measurement data to the VSMOW-SLAP (Vienna Standard Mean Ocean Water-Standard Light Antarctic Precipitation) scale, and their use improves accuracy of the data by eliminating evaporative loss and associated isotopic fractionation while

On-line hydrogen-isotope measurements of organic samples using elemental chromium: an extension for high temperature elemental-analyzer techniques.

Science.gov (United States)

Gehre, Matthias; Renpenning, Julian; Gilevska, Tetyana; Qi, Haiping; Coplen, Tyler B; Meijer, Harro A J; Brand, Willi A; Schimmelmann, Arndt

2015-01-01

The high temperature conversion (HTC) technique using an elemental analyzer with a glassy carbon tube and filling (temperature conversion/elemental analysis, TC/EA) is a widely used method for hydrogen isotopic analysis of water and many solid and liquid organic samples with analysis by isotope-ratio mass spectrometry (IRMS). However, the TC/EA IRMS method may produce inaccurate δ(2)H results, with values deviating by more than 20 mUr (milliurey = 0.001 = 1‰) from the true value for some materials. We show that a single-oven, chromium-filled elemental analyzer coupled to an IRMS substantially improves the measurement quality and reliability for hydrogen isotopic compositions of organic substances (Cr-EA method). Hot chromium maximizes the yield of molecular hydrogen in a helium carrier gas by irreversibly and quantitatively scavenging all reactive elements except hydrogen. In contrast, under TC/EA conditions, heteroelements like nitrogen or chlorine (and other halogens) can form hydrogen cyanide (HCN) or hydrogen chloride (HCl) and this can cause isotopic fractionation. The Cr-EA technique thus expands the analytical possibilities for on-line hydrogen-isotope measurements of organic samples significantly. This method yielded reproducibility values (1-sigma) for δ(2)H measurements on water and caffeine samples of better than 1.0 and 0.5 mUr, respectively. To overcome handling problems with water as the principal calibration anchor for hydrogen isotopic measurements, we have employed an effective and simple strategy using reference waters or other liquids sealed in silver-tube segments. These crimped silver tubes can be employed in both the Cr-EA and TC/EA techniques. They simplify considerably the normalization of hydrogen-isotope measurement data to the VSMOW-SLAP (Vienna Standard Mean Ocean Water-Standard Light Antarctic Precipitation) scale, and their use improves accuracy of the data by eliminating evaporative loss and associated isotopic fractionation while

High spin structures in 194Hg

International Nuclear Information System (INIS)

Fotiades, N.; Vlastou, R.; Serris, M.; Sharpey-Schafer, J.F.; Fallon, P.; Riley, M.A.; Clark, R.M.; Hauschild, K.; Wadsworth, R.

1996-01-01

High spin states in the isotope 194 Hg were populated using the 150 Nd( 48 Ca,4n) reaction at a beam energy of 213 MeV. The analysis of γ-γ coincidences has revealed two new structures at excitation energies above 6 MeV and at moderate spin. The two structures are a manifestation of the deviation of nucleus from the collective rotation which dominates its lower excitation behaviour. A comparison with similar structures in the neighbouring Hg isotopes is also attempted. (orig.)

A 2000-2010 years outlook of isotopic uranium enrichment

International Nuclear Information System (INIS)

Vasaru, G.

1998-01-01

The increase of the installed power in nuclear plants implies the following steps to be achieved: - developing a parallel industry for the nuclear fuel cycle able to ensure a rhythmic supply of natural uranium, possibly an isotopic enrichment of 235 U of around 1.2 - 3.2%, depending on the reactor system; - manufacturing the fuel elements and the operation of cycle back-end, which may, possibly, include a temporary storage of the irradiated fuel; - reprocessing the spend fuel; - radioactive waste processing in view of final disposal, as well as the recovery of un-spent uranium and of plutonium formed. The heavy water reactors of CANDU-PHW does not imply any isotopic enrichment but provides a lower burnup of only 7,000 MW day/tone. An enrichment to 1.2% in 235 U for this type of reactors could increase the burnup up to 20,000 MW day/tone. An advanced method of enriching 235 U is based on the Atomic Vapor Laser Isotop Separation (AVLIS). This procedure called AVLIS has several advantages which are pointed out in this paper, among which: a very high selectivity; high separation factors; a low energy consumption due to the fact that in the conditions of a selective photo ionization, the energy necessary to the process is only 6.2 eV for the separated 235 U atom vs 0.3 MeV in case of inertial separators or 3 MeV in case of gaseous diffusion procedure. With the current laser yields an energy consumption of 100 kWh/SWU is estimated for AVLIS procedures as compared with 2,400 kWh/SWU in case of gaseous diffusion; an almost entire extraction of 235 U, what ensures a more efficient utilisation of nuclear fuel. Due to its modular character and to potential improvement in the equipment which could be achieved, this procedure will ensure a reduction in the investment costs in the construction stage what will make AVLIS a substitute of the classical separation procedures

Temporal and spatial distribution of isotopes in river water in Central Europe: 50 years experience with the Austrian network of isotopes in rivers.