WorldWideScience

Sample records for ion kinetic energy

  1. Kinetic energy dissipation in heavy-ion collisions

    International Nuclear Information System (INIS)

    Fedotov, S.I.; Jolos, R.V.; Kartavenko, V.G.

    1979-01-01

    Kinetic energy dissipation mechanism is considered in deep inelastic heavy-ion collisions. It is shown that the significant part of the kinetic energy loss can be explained by the excitation of the nuclear matter multipole vibrations. The main contribution of the energy dissipation is given by the time dependent heavy-ion interaction potential renormalized due to the nuclear excitations, rather than by the velocity proportional frictional forces

  2. Kinetics of interaction from low-energy-ion bombardment of surfaces

    International Nuclear Information System (INIS)

    Horton, C.C.

    1988-01-01

    The kinetics of interaction from low energy oxygen ion bombardment of carbon and Teflon surfaces have been investigated. The surfaces were bombarded with 4.5 to 93 eV oxygen ions and emitted species were observed with a mass spectrometer. To obtain the kinetic information, the ion beam was square pulse modulated and reaction products were observed as a function of time. The kinetic information is contained in the response of the emitted species to the pulsed ion beam. Oxygen bombardment of carbon produced CO in three parallel branches with each following an adsorption-desorption process. The fast branch, with a rate constants of 12,000/sec, appeared to be sputter induced an was absent below about 19 eV. The medium and slow branches, with rate constants of 850/sec and 45/sec respectively, has little energy dependence and appeared to be due to chemical sputtering from two sites. The ratio of the fraction of the medium branch to that of the slow was constant at 1:3. The bombardment of Teflon produced CF in two parallel branches, with one following a series process and the other an adsorb-desorb process. The rate constant of the other branch were 22,000/sec and 7,000/sec and the rate constant of the other branch was 90/sec. The total signal fell monotonically with decreasing ion energy with the fraction for each branch holding constant at 71% for the series and 29% for the adsorb-desorb

  3. Kinetic energy distributions of ions after surface collisions

    International Nuclear Information System (INIS)

    Short, R.T.; Todd, P.J.; Grimm, C.C.

    1991-01-01

    As a part of the development of an organic ion microprobe, to be used for imaging of particular organic compounds in biological tissue, various methods of quadrupole-based tandem mass spectroscopy (MS/MS) have been investigated. High transmission efficiency is essential for the success of the organic ion microprobe, due to expected low analyte concentrations in biological tissue and the potential for sample damage from prolonged exposure to the primary ion beam. MS/MS is necessary for organic ion imaging because of the complex nature of the biological matrices. The goal of these studies of was to optimize the efficiency of daughter ion production and transmission by first determining daughter ion properties and then designing ion optics based on those properties. The properties of main interest are daughter ion kinetic energy and angular distribution. 1 fig

  4. Ion kinetic energy distribution in a pulsed vacuum arc with a straight magnetic filter

    International Nuclear Information System (INIS)

    Giuliani, L; Grondona, D; Kelly, H; Minotti, F

    2008-01-01

    In vacuum arcs of interest for film deposition the ion kinetic energy is of importance because it influences the coating properties. In this kind of discharge, the ions come out from the cathode spots with a high kinetic energy (20-150 eV). In the present work, we present measurements of vacuum arc ion energy distributions in a pulsed vacuum arc with a straight magnetic filter. A retarding field analyser (RFA) was used to perform the measurements that were carried out with a variable magnetic field strength (of the order of 10 mT). Since the interpretation of the results obtained from the RFA lies in the knowledge of the plasma and floating potential values, we have employed also Langmuir probes for determining those quantities. The obtained results for the ion kinetic energy are similar to those reported by other authors, but they were also found to be independent of the magnetic field strength. The electron temperature was also found to be independent of the magnetic field strength and of the axial position along the filter, indicating the absence of collisions.

  5. Kinetic energy budget for electroconvective flows near ion selective membranes

    Science.gov (United States)

    Wang, Karen; Mani, Ali

    2017-11-01

    Electroconvection occurs when ions are driven from a bulk fluid through an ion-selective surface. When the driving voltage is beyond a threshold, this process undergoes a hydrodynamic instability called electroconvection, which can become chaotic due to nonlinear coupling between ion-transport, fluid flow, and electrostatic forces. Electroconvection significantly enhances ion transport and plays an important role in a wide range of electrochemical applications. We investigate this phenomenon by considering a canonical geometry consisting of a symmetric binary electrolyte between an ion-selective membrane and a reservoir using 2D direct numerical simulation (DNS). Our simulations reveal that for most practical regimes, DNS of electroconvection is expensive. Thus, a plan towards development of reduced-order models is necessary to facilitate the adoption of analysis of this phenomenon in industry. Here we use DNS to analyze the kinetic energy budget to shed light into the mechanisms sustaining flow and mixing in electroconvective flows. Our analysis reveals the relative dominance of kinetic energy sources, dissipation, and transport mechanisms sustaining electroconvection at different distances from the interface and over a wide range of input parameters. Karen Wang was supported by the National Defense Science & Engineering Graduate Fellowship (NDSEG). Ali Mani was supported by the National Science Foundation Award.

  6. Kinetic energy of ions produced with first-, second-, and multi-shot femtosecond laser ablation on a solid surface

    International Nuclear Information System (INIS)

    Kobayashi, Tohru; Kato, Toshiyuki; Kurata-Nishimura, Mizuki; Matsuo, Yukari; Kawai, Jun; Motobayashi, Tohru; Hayashizaki, Yoshihide

    2007-01-01

    We report that the kinetic energy of samarium (Sm) atom and Sm + ion produced by femtosecond laser ablation of solid samarium is strongly dependent on the number of ablation laser shots in the range from 1 to 10. By ablating the fresh surface (i.e. 1st shot), we find the kinetic energy of both Sm and Sm + ion to be the largest (24 and 250 eV, respectively). Almost 10 times larger kinetic energy of Sm + ion than that of Sm clearly indicates the contribution of Coulomb explosion in the acceleration process. From the second shot, kinetic energies of Sm and Sm + ion are lower than those of the first shot and almost constant (ca. 12 and 80 eV, respectively). This behaviour suggests the change in the nature of the solid surface after femtosecond laser ablation, which can be explained by the amorphization of ablated sample surface reported in recent studies

  7. Energy deposition by heavy ions: additivity of kinetic and potential energy contributions in hillock formation on CaF2.

    Science.gov (United States)

    Wang, Y Y; Grygiel, C; Dufour, C; Sun, J R; Wang, Z G; Zhao, Y T; Xiao, G Q; Cheng, R; Zhou, X M; Ren, J R; Liu, S D; Lei, Y; Sun, Y B; Ritter, R; Gruber, E; Cassimi, A; Monnet, I; Bouffard, S; Aumayr, F; Toulemonde, M

    2014-07-18

    Modification of surface and bulk properties of solids by irradiation with ion beams is a widely used technique with many applications in material science. In this study, we show that nano-hillocks on CaF2 crystal surfaces can be formed by individual impact of medium energy (3 and 5 MeV) highly charged ions (Xe(22+) to Xe(30+)) as well as swift (kinetic energies between 12 and 58 MeV) heavy xenon ions. For very slow highly charged ions the appearance of hillocks is known to be linked to a threshold in potential energy (Ep) while for swift heavy ions a minimum electronic energy loss per unit length (Se) is necessary. With our results we bridge the gap between these two extreme cases and demonstrate, that with increasing energy deposition via Se the Ep-threshold for hillock production can be lowered substantially. Surprisingly, both mechanisms of energy deposition in the target surface seem to contribute in an additive way, which can be visualized in a phase diagram. We show that the inelastic thermal spike model, originally developed to describe such material modifications for swift heavy ions, can be extended to the case where both kinetic and potential energies are deposited into the surface.

  8. Kinetic energy and charge distributions of multiply charged ions produced by heavy ions and by synchrotron radiation

    International Nuclear Information System (INIS)

    Levin, J.C.; Biedermann, C.; Cederquist, H.; Liljeby, L.; Short, R.T.; Sellin, I.A.

    1989-01-01

    This paper contrasts two methods of production of multiply charged ions which may have application in future hot-atom chemistry experiments. Interest in extending the study of ion-atom collisions from MeV to keV to eV energies has grown rapidly in the last decade as previously inaccessible astrophysical, fusion, and spectroscopic problems have been addressed. One of these methods involves highly charged secondary beams formed from ions created in dilute gas samples irradiated by fast (MeV), high-charge-state, heavy ions. The measurements show, however, that such ions often have mean recoil energies two orders of magnitude higher than kinetic energies of ions in similar charge states resulting from vacancy cascades of atomic inner shells photoionized by synchrotron x rays. These results may be applicable to development of a cold source of highly charged ions featuring low energy spread and good angular definition. Results from other laboratories (Grandin et al at Ganil, Ullrich et al in Frankfurt, and Watson et al at Texas A ampersand M) will also be discussed

  9. Improving the signal-to-noise ratio in mass and ion kinetic energy spectrometers

    International Nuclear Information System (INIS)

    Brenton, A.G.; Beynon, J.H.; Morgan, R.P.

    1979-01-01

    The signal-to-noise ratio in mass and ion kinetic energy spectrometers is limited by noise generated from the presence of scattered ions and neutrals. Methods of eliminating this are illustrated with reference to the ZAB-2F instrument manufactured by VG-Micromass Ltd. It is estimated that after the modifications the instrument is capable, on a routine basis, of measuring peaks corresponding to the arrival of ions at a rate of the order of 1 ion s -1 . (Auth.)

  10. Variation of kinetic energy release with temperature and electron energy for unimolecular ionic transitions

    International Nuclear Information System (INIS)

    Rabia, M.A.; Fahmy, M.A.

    1992-01-01

    The kinetic energy released during seven unimolecular ionic transitions, generated from benzyl alcohol and benzyl amine have been studied as a function of ion source temperature and ionizing electron energy. Only, the kinetic energy released during H CN elimination from fragment [C 7 H 8 N]+ ion of benzyl amine displays a temperature dependence. For only two transitions, generated from benzyl alcohol, the kinetic energy released show a significant ionizing electron energy dependence. These results may reveal the role of the internal energy of reacting ions in producing the kinetic energy released some transitions produced from benzyl alcohol

  11. Binding energies of cluster ions

    International Nuclear Information System (INIS)

    Parajuli, R.; Matt, S.; Scheier, P.; Echt, O.; Stamatovic, A.; Maerk, T.D.

    2002-01-01

    The binding energy of charged clusters may be measured by analyzing the kinetic energy released in the metastable decay of mass selected parent ions. Using finite heat bath theory to determine the binding energies of argon, neon, krypton, oxygen and nitrogen from their respective average kinetic energy released were carried out. A high-resolution double focussing two-sector mass spectrometer of reversed Nier-Johnson type geometry was used. MIKE ( mass-analysed ion kinetic energy) were measured to investigate decay reactions of mass-selected ions. For the inert gases neon (Ne n + ), argon (Ar n + ) and krypton (Kr n + ), it is found that the binding energies initially decrease with increasing size n and then level off at a value above the enthalpy of vaporization of the condensed phase. Oxygen cluster ions shown a characteristic dependence on cluster size (U-shape) indicating a change in the metastable fragmentation mechanism when going from the dimer to the decamer ion. (nevyjel)

  12. A method for ion distribution function evaluation using escaping neutral atom kinetic energy samples

    International Nuclear Information System (INIS)

    Goncharov, P.R.; Ozaki, T.; Veshchev, E.A.; Sudo, S.

    2008-01-01

    A reliable method to evaluate the probability density function for escaping atom kinetic energies is required for the analysis of neutral particle diagnostic data used to study the fast ion distribution function in fusion plasmas. Digital processing of solid state detector signals is proposed in this paper as an improvement of the simple histogram approach. Probability density function for kinetic energies of neutral particles escaping from the plasma has been derived in a general form taking into account the plasma ion energy distribution, electron capture and loss rates, superposition along the diagnostic sight line and the magnetic surface geometry. A pseudorandom number generator has been realized that enables a sample of escaping neutral particle energies to be simulated for given plasma parameters and experimental conditions. Empirical probability density estimation code has been developed and tested to reconstruct the probability density function from simulated samples assuming. Maxwellian and classical slowing down plasma ion energy distribution shapes for different temperatures and different slowing down times. The application of the developed probability density estimation code to the analysis of experimental data obtained by the novel Angular-Resolved Multi-Sightline Neutral Particle Analyzer has been studied to obtain the suprathermal particle distributions. The optimum bandwidth parameter selection algorithm has also been realized. (author)

  13. Making waves: Kinetic processes controlling surface evolution during low energy ion sputtering

    International Nuclear Information System (INIS)

    Chan, W.L.; Chason, Eric

    2007-01-01

    When collimated beams of low energy ions are used to bombard materials, the surface often develops a periodic pattern or ''ripple'' structure. Different types of patterns are observed to develop under different conditions, with characteristic features that depend on the substrate material, the ion beam parameters, and the processing conditions. Because the patterns develop spontaneously, without applying any external mask or template, their formation is the expression of a dynamic balance among fundamental surface kinetic processes, e.g., erosion of material from the surface, ion-induced defect creation, and defect-mediated evolution of the surface morphology. In recent years, a comprehensive picture of the different kinetic mechanisms that control the different types of patterns that form has begun to emerge. In this article, we provide a review of different mechanisms that have been proposed and how they fit together in terms of the kinetic regimes in which they dominate. These are grouped into regions of behavior dominated by the directionality of the ion beam, the crystallinity of the surface, the barriers to surface roughening, and nonlinear effects. In sections devoted to each type of behavior, we relate experimental observations of patterning in these regimes to predictions of continuum models and to computer simulations. A comparison between theory and experiment is used to highlight strengths and weaknesses in our understanding. We also discuss the patterning behavior that falls outside the scope of the current understanding and opportunities for advancement

  14. A quadrupole ion trap as low-energy cluster ion beam source

    CERN Document Server

    Uchida, N; Kanayama, T

    2003-01-01

    Kinetic energy distribution of ion beams was measured by a retarding field energy analyzer for a mass-selective cluster ion beam deposition system that uses a quadrupole ion trap as a cluster ion beam source. The results indicated that the system delivers a cluster-ion beam with energy distribution of approx 2 eV, which corresponded well to the calculation results of the trapping potentials in the ion trap. Using this deposition system, mass-selected hydrogenated Si cluster ions Si sub n H sub x sup + were actually deposited on Si(111)-(7x7) surfaces at impact kinetic energy E sub d of 3-30 eV. Observation by using a scanning tunneling microscope (STM) demonstrated that Si sub 6 H sub x sup + cluster ions landed on the surface without decomposition at E sub d =3 eV, while the deposition was destructive at E sub d>=18 eV. (author)

  15. Cluster-assisted multiple ionization of methyl iodide by a nanosecond laser: Influence of laser intensity on the kinetic energy and peak profile of multicharged ions

    International Nuclear Information System (INIS)

    Wen Lihua; Li Haiyang; Luo Xiaolin; Niu Dongmei; Xiao Xue; Wang Bin; Liang Feng; Hou Keyong; Shao Shiyong

    2006-01-01

    The dependences of kinetic energies and peak profiles of multicharged ions of I q+ (q = 2-3) and C 2+ on the laser intensity have been studied in detail by time-of-flight mass spectrometry, those multicharged ions are produced by irradiation of methyl iodide cluster beam with a nanosecond 532 nm Nd-YAG laser. Our experiments show that the kinetic energies released of multicharged ions increase linearly with the laser intensity in the range of 3 x 10 9 -2 x 10 11 W/cm 2 . The peaks of multicharged ions are split to forward ions and backward ions, and the ratio of the backward ions to forward ions decreases exponentially with laser intensity. The decreasing of backward ions is probably due to Coulomb scattering by the heavier I + ions when they turn around through the laser focus point. The linear dependence of kinetic energy of multicharged ions on laser intensity is interpreted by the ionization mechanism, in which the laser induced inverse bremsstrahlung heating of electron is the rate-limiting step

  16. Simulation of ITG instabilities with fully kinetic ions and drift-kinetic electrons in tokamaks

    Science.gov (United States)

    Hu, Youjun; Chen, Yang; Parker, Scott

    2017-10-01

    A turbulence simulation model with fully kinetic ions and drift-kinetic electrons is being developed in the toroidal electromagnetic turbulence code GEM. This is motivated by the observation that gyrokinetic ions are not well justified in simulating turbulence in tokamak edges with steep density profile, where ρi / L is not small enough to be used a small parameter needed by the gyrokinetic ordering (here ρi is the gyro-radius of ions and L is the scale length of density profile). In this case, the fully kinetic ion model may be useful. Our model uses an implicit scheme to suppress high-frequency compressional Alfven waves and waves associated with the gyro-motion of ions. The ion orbits are advanced by using the well-known Boris scheme, which reproduces correct drift-motion even with large time-step comparable to the ion gyro-period. The field equation in this model is Ampere's law with the magnetic field eliminated by using an implicit scheme of Faraday's law. The current contributed by ions are computed by using an implicit δf method. A flux tube approximation is adopted, which makes the field equation much easier to solve. Numerical results of electromagnetic ITG obtained from this model will be presented and compared with the gyrokinetic results. This work is supported by U.S. Department of Energy, Office of Fusion Energy Sciences under Award No. DE-SC0008801.

  17. Kinetic energies of charged fragments resulting from multifragmentation and asymmetric fission of the C60 molecule in collisions with monocharged ions (2-130 keV)

    International Nuclear Information System (INIS)

    Rentenier, A; Bordenave-Montesquieu, D; Moretto-Capelle, P; Bordenave-Montesquieu, A

    2003-01-01

    Multifragmentation and asymmetric fission (AF) of the C 60 molecule induced by H + , H 2 + , H 3 + and He + ions at medium collision energies (2-130 keV) are considered. Momenta and kinetic energies of C n + fragment ions (n = 1- 12) are deduced from an analysis of time-of-flight spectra. In multifragmentation processes, momenta are found to be approximately constant when n > 2, a behaviour which explains that the most probable kinetic energy, as well as the width of the kinetic energy distributions, is found to be inversely proportional to the fragment size n; both momenta and kinetic energies are independent of the velocity and nature of the projectile, and hence of the energy deposit. A specific study of the AF shows that the kinetic energies of C 2 + , C 4 + and C 6 + fragments are also independent of the collision velocity and projectile species; a quantitative agreement is found with values deduced from kinetic energy release measurements by another group in electron impact experiments, and the observed decrease when the mass of the light fragment increases is also reproduced. A quantitative comparison of AF and multifragmentation for the n = 2, 4 and 6 fragment ions shows that kinetic energies in AF exceed that in multifragmentation, a result which explains the oscillations observed when momenta or kinetic energies of fragments are plotted against the n-value. The AF yield is also found to scale with the energy deposit in the collision velocity range extending below the velocity at the maximum of the electronic stopping power; except for protons, it remains negligible with respect to multifragmentation as soon as the total energy deposit exceeds about 100 eV

  18. Kinetic energies of charged fragments resulting from multifragmentation and asymmetric fission of the C{sub 60} molecule in collisions with monocharged ions (2-130 keV)

    Energy Technology Data Exchange (ETDEWEB)

    Rentenier, A; Bordenave-Montesquieu, D; Moretto-Capelle, P; Bordenave-Montesquieu, A [Laboratoire CAR-IRSAMC, UMR 5589 CNRS - Universite Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex (France)

    2003-04-28

    Multifragmentation and asymmetric fission (AF) of the C{sub 60} molecule induced by H{sup +}, H{sub 2}{sup +}, H{sub 3}{sup +} and He{sup +} ions at medium collision energies (2-130 keV) are considered. Momenta and kinetic energies of C{sub n}{sup +} fragment ions (n = 1- 12) are deduced from an analysis of time-of-flight spectra. In multifragmentation processes, momenta are found to be approximately constant when n > 2, a behaviour which explains that the most probable kinetic energy, as well as the width of the kinetic energy distributions, is found to be inversely proportional to the fragment size n; both momenta and kinetic energies are independent of the velocity and nature of the projectile, and hence of the energy deposit. A specific study of the AF shows that the kinetic energies of C{sub 2}{sup +}, C{sub 4}{sup +} and C{sub 6}{sup +} fragments are also independent of the collision velocity and projectile species; a quantitative agreement is found with values deduced from kinetic energy release measurements by another group in electron impact experiments, and the observed decrease when the mass of the light fragment increases is also reproduced. A quantitative comparison of AF and multifragmentation for the n = 2, 4 and 6 fragment ions shows that kinetic energies in AF exceed that in multifragmentation, a result which explains the oscillations observed when momenta or kinetic energies of fragments are plotted against the n-value. The AF yield is also found to scale with the energy deposit in the collision velocity range extending below the velocity at the maximum of the electronic stopping power; except for protons, it remains negligible with respect to multifragmentation as soon as the total energy deposit exceeds about 100 eV.

  19. Energy partitioning constraints at kinetic scales in low-β turbulence

    Science.gov (United States)

    Gershman, Daniel J.; F.-Viñas, Adolfo; Dorelli, John C.; Goldstein, Melvyn L.; Shuster, Jason; Avanov, Levon A.; Boardsen, Scott A.; Stawarz, Julia E.; Schwartz, Steven J.; Schiff, Conrad; Lavraud, Benoit; Saito, Yoshifumi; Paterson, William R.; Giles, Barbara L.; Pollock, Craig J.; Strangeway, Robert J.; Russell, Christopher T.; Torbert, Roy B.; Moore, Thomas E.; Burch, James L.

    2018-02-01

    Turbulence is a fundamental physical process through which energy injected into a system at large scales cascades to smaller scales. In collisionless plasmas, turbulence provides a critical mechanism for dissipating electromagnetic energy. Here, we present observations of plasma fluctuations in low-β turbulence using data from NASA's Magnetospheric Multiscale mission in Earth's magnetosheath. We provide constraints on the partitioning of turbulent energy density in the fluid, ion-kinetic, and electron-kinetic ranges. Magnetic field fluctuations dominated the energy density spectrum throughout the fluid and ion-kinetic ranges, consistent with previous observations of turbulence in similar plasma regimes. However, at scales shorter than the electron inertial length, fluctuation power in electron kinetic energy significantly exceeded that of the magnetic field, resulting in an electron-motion-regulated cascade at small scales. This dominance is highly relevant for the study of turbulence in highly magnetized laboratory and astrophysical plasmas.

  20. Cluster ion-surface interactions: from meV to MeV energies

    Energy Technology Data Exchange (ETDEWEB)

    Nordlund, Kai; Meinander, Kristoffer; Jaervi, Tommi T.; Peltola, Jarkko; Samela, Juha [Accelerator Laboratory, University of Helsinki (Finland)

    2008-07-01

    The nature of cluster ion-surface interactions changes dramatically with the kinetic energy of the incoming cluster species. In this talk I review some of our recent work on the nature of cluster-surface interactions spanning an energy range from a few MeV/cluster to about 1 MeV/cluster and cluster sizes in the range of 10 - 1000 atoms/cluster. In the energy range of a few MeV/cluster ion, the kinetic energy of the incoming ion is insignificant compared to the energy gained when the surface potential energy at the cluster-surface interface is released and partly translated into kinetic energy. Even in this energy regime I show that surprisingly drastic effects can occur. When the energy of the incoming cluster is raised to a few eV/atom, the kinetic energy of the incoming cluster starts to affect the deposition. It will cause the cluster to entirely reform on impact. When the energy is raised to the range of keV's/cluster, the clusters start to penetrate the sample, fairly similar to conventional ion implantation. However, in dense targets the cluster ions may stick close to each other long enough to cause a significant enhancement of the heat spike in the material. Finally, I show that at kinetic energies around 1 MeV/cluster the cluster enhancement of the heat spike may lead to dramatic surface effects.

  1. Energy Properties of Ion Acoustic Waves in Stable and Unstable Plasmas

    DEFF Research Database (Denmark)

    Jensen, Vagn Orla; Lynov, Jens-Peter

    1979-01-01

    Energy exchange between potential energy and ion kinetic energy in an ion acoustic wave is considered. In order to investigate the linear Landau damping or growth, the energy is calculated by use of first‐order quantities only so that nonlinear effects are not involved. It is found that for ion...... acoustic waves that are growing or damped in space the time average of the sum of the potential and the kinetic energy density is independent of position. Energy absorption spectra in particle velocity space are calculated; they are relatively broad and complicated functions. This shows that plasma ions...... of all velocities exchange energy with the wave....

  2. Morphology and annealing kinetics of ion tracks in minerals

    Directory of Open Access Journals (Sweden)

    Ewing R. C.

    2012-10-01

    Full Text Available We have studied the morphology and annealing kinetics of ion tracks in Durango apatite using synchrotron small angle X-ray scattering. The non-destructive, artefact-free technique enables us to determine the track radii with a resolution of fractions of a nanometre. The tracks were generated using different heavy ions with energies between 185 MeV and 2.6 GeV. The track morphology is consistent with the formation of long cylindrical amorphous tracks. The annealing kinetics, measured by SAXS in combination with ex situ and in situ annealing experiments, suggests structural relaxation followed by recrystallisation of the damaged material. The measurement methodology shown here provides a new means for in-depth studies of ion-track formation in minerals under a wide variety of geological conditions.

  3. Investigations on the influence of ion kinetic energy on mass discrimination in isotope ratio measurements using MC-ICPMS

    International Nuclear Information System (INIS)

    Fontaine, G.H.; Hattendorf, B.; Oberli, F.; Bourdon, B.; Guenther, D.

    2009-01-01

    Full text: Systematic dependence of mass discrimination on ICP operating parameters was investigated for two MCICPMS instruments, a Nu Plasma HR and a Nu Plasma 1700, which differ both in acceleration voltage and spectrometer geometry. Gas temperature variations were determined by absolute pressure measurements at the vacuum interface. Their influence on ion kinetic energy as monitored by means of a retardation filter fitted in front of an ion counting detector will be discussed and compared to effects resulting from variations in acceleration voltage. (author)

  4. Electron and ion kinetics in a micro hollow cathode discharge

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G J; Iza, F; Lee, J K [Electronics and Electrical Engineering Department, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

    2006-10-21

    Electron and ion kinetics in a micro hollow cathode discharge are investigated by means of two-dimensional axisymmetric particle-in-cell Monte Carlo collision simulations. Argon discharges at 10 and 300 Torr are studied for various driving currents. Electron and ion energy probability functions (IEPF) are shown at various times and locations to study the spatio-temporal behaviour of the discharge. The electron energy probability function (EEPF) evolves from the Druyvesteyn type in the early stages of the discharge into a two (or three) temperature distribution when steady state is reached. In steady state, secondary electrons accelerated across the cathode fall populate the high energy tail of the EEPF while the low energy region is populated by trapped electrons. The IEPF evolves from a Maxwellian in the negative glow (bulk) to a two temperature distribution on the cathode surface. The overpopulation of low energy ions near the cathode surface is attributed to a larger collision cross section for low energy ions and ionization within the cathode fall.

  5. Electron and ion kinetics in a micro hollow cathode discharge

    International Nuclear Information System (INIS)

    Kim, G J; Iza, F; Lee, J K

    2006-01-01

    Electron and ion kinetics in a micro hollow cathode discharge are investigated by means of two-dimensional axisymmetric particle-in-cell Monte Carlo collision simulations. Argon discharges at 10 and 300 Torr are studied for various driving currents. Electron and ion energy probability functions (IEPF) are shown at various times and locations to study the spatio-temporal behaviour of the discharge. The electron energy probability function (EEPF) evolves from the Druyvesteyn type in the early stages of the discharge into a two (or three) temperature distribution when steady state is reached. In steady state, secondary electrons accelerated across the cathode fall populate the high energy tail of the EEPF while the low energy region is populated by trapped electrons. The IEPF evolves from a Maxwellian in the negative glow (bulk) to a two temperature distribution on the cathode surface. The overpopulation of low energy ions near the cathode surface is attributed to a larger collision cross section for low energy ions and ionization within the cathode fall

  6. Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.

    Science.gov (United States)

    Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M

    2015-03-27

    An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19}  W/  cm^{2}. Highly charged gold ions with kinetic energies up to >200  MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.

  7. Kinetic treatment of nonlinear ion-acoustic waves in multi-ion plasma

    Science.gov (United States)

    Ahmad, Zulfiqar; Ahmad, Mushtaq; Qamar, A.

    2017-09-01

    By applying the kinetic theory of the Valsove-Poisson model and the reductive perturbation technique, a Korteweg-de Vries (KdV) equation is derived for small but finite amplitude ion acoustic waves in multi-ion plasma composed of positive and negative ions along with the fraction of electrons. A correspondent equation is also derived from the basic set of fluid equations of adiabatic ions and isothermal electrons. Both kinetic and fluid KdV equations are stationary solved with different nature of coefficients. Their differences are discussed both analytically and numerically. The criteria of the fluid approach as a limiting case of kinetic theory are also discussed. The presence of negative ion makes some modification in the solitary structure that has also been discussed with its implication at the laboratory level.

  8. Study of uranium dioxyde sputtering induced by multicharged heavy ions at low and very low kinetic energy: projectile charge effect

    International Nuclear Information System (INIS)

    Haranger, F.

    2003-12-01

    Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)

  9. Fully kinetic simulation of ion acoustic and dust-ion acoustic waves

    International Nuclear Information System (INIS)

    Hosseini Jenab, S. M.; Kourakis, I.; Abbasi, H.

    2011-01-01

    A series of numerical simulations is presented, based on a recurrence-free Vlasov kinetic model using kinetic phase point trajectories. All plasma components are modeled kinetically via a Vlasov evolution equation, then coupled through Poisson's equation. The dynamics of ion acoustic waves in an electron-ion and in a dusty (electron-ion-dust) plasma configuration are investigated, focusing on wave decay due to Landau damping and, in particular, on the parametric dependence of the damping rate on the dust concentration and on the electron-to-ion temperature ratio. In the absence of dust, the occurrence of damping was observed, as expected, and its dependence to the relative magnitude of the electron vs ion temperature(s) was investigated. When present, the dust component influences the charge balance, enabling dust-ion acoustic waves to survive Landau damping even in the extreme regime where T e ≅ T i . The Landau damping rate is shown to be minimized for a strong dust concentration or/and for a high value of the electron-to-ion temperature ratio. Our results confirm earlier theoretical considerations and contribute to the interpretation of experimental observations of dust-ion acoustic wave characteristics.

  10. Kinetic modeling of particle dynamics in H− negative ion sources (invited)

    International Nuclear Information System (INIS)

    Hatayama, A.; Shibata, T.; Nishioka, S.; Ohta, M.; Yasumoto, M.; Nishida, K.; Yamamoto, T.; Miyamoto, K.; Fukano, A.; Mizuno, T.

    2014-01-01

    Progress in the kinetic modeling of particle dynamics in H − negative ion source plasmas and their comparisons with experiments are reviewed, and discussed with some new results. Main focus is placed on the following two topics, which are important for the research and development of large negative ion sources and high power H − ion beams: (i) Effects of non-equilibrium features of EEDF (electron energy distribution function) on H − production, and (ii) extraction physics of H − ions and beam optics

  11. Fragmentation of acetic acid ions with selected internal energies

    Science.gov (United States)

    Zha, Qingmei; Nishimura, Toshihide; Bertrand, Michel J.; Meisels, G. G.

    1991-08-01

    The unimolecular dissociation of acetic acid ion in the photon energy range 10.5-17.0 eV was studied using threshold photoelectron photoion coincidence mass spectrometry. The detailed breakdown graph was obtained and the fragmentation pathways were elucidated. The breakdown graph calculated using statistical theories was found to be consistent with the experimental data up to a photon energy of about 12.5 eV. The average kinetic energy release observed is higher than that calculated on the basis of quasi-equilibrium theory for the formation of COOH+ while it seems to be statistical for the formation of CH3CO+. The origin of kinetic energy release accompanying the formation of these two ions is discussed. The structure of [COH3]+ ion (m/z 31) is determined to be hydroxymethyl cation, CH2OH+, which could be formed by a two-step rearrangement prior to dissociation.

  12. Influence of the interaction volume on the kinetic energy resolution of a velocity map imaging spectrometer

    International Nuclear Information System (INIS)

    Zhang Peng; Feng Zheng-Peng; Luo Si-Qiang; Wang Zhe

    2016-01-01

    We investigate the influence of the interaction volume on the energy resolution of a velocity map imaging spectrometer. The simulation results show that the axial interaction size has a significant influence on the resolution. This influence is increased for a higher kinetic energy. We further show that the radial interaction size has a minor influence on the energy resolution for the electron or ion with medium energy, but it is crucial for the resolution of the electron or ion with low kinetic energy. By tracing the flight trajectories we show how the electron or ion energy resolution is influenced by the interaction size. (paper)

  13. Ion-induced particle desorption in time-of-flight medium energy ion scattering

    Science.gov (United States)

    Lohmann, S.; Primetzhofer, D.

    2018-05-01

    Secondary ions emitted from solids upon ion impact are studied in a time-of-flight medium energy ion scattering (ToF-MEIS) set-up. In order to investigate characteristics of the emission processes and to evaluate the potential for surface and thin film analysis, experiments employing TiN and Al samples were conducted. The ejected ions exhibit a low initial kinetic energy of a few eV, thus, requiring a sufficiently high acceleration voltage for detection. Molecular and atomic ions of different charge states originating both from surface contaminations and the sample material are found, and relative yields of several species were determined. Experimental evidence that points towards a predominantly electronic sputtering process is presented. For emitted Ti target atoms an additional nuclear sputtering component is suggested.

  14. Electron screening and kinetic-energy oscillations in a strongly coupled plasma

    International Nuclear Information System (INIS)

    Chen, Y.C.; Simien, C.E.; Laha, S.; Gupta, P.; Martinez, Y.N.; Mickelson, P.G.; Nagel, S.B.; Killian, T.C.

    2004-01-01

    We study equilibration of strongly coupled ions in an ultracold neutral plasma produced by photoionizing laser-cooled and trapped atoms. By varying the electron temperature, we show that electron screening modifies the equilibrium ion temperature. Even with few electrons in a Debye sphere, the screening is well described by a model using a Yukawa ion-ion potential. We also observe damped oscillations of the ion kinetic energy that are a unique feature of equilibration of a strongly coupled plasma

  15. Ion induced high energy electron emission from copper

    International Nuclear Information System (INIS)

    Ruano, G.; Ferron, J.

    2008-01-01

    We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He + , Ne + and Ar + ) and Li + ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

  16. Kinetic modeling of particle dynamics in H{sup −} negative ion sources (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Hatayama, A., E-mail: akh@ppl.appi.keio.ac.jp; Shibata, T.; Nishioka, S.; Ohta, M.; Yasumoto, M.; Nishida, K.; Yamamoto, T. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522 (Japan); Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Fukano, A. [Monozukuri Department, Tokyo Metropolitan College of Industrial Technology, Shinagawa, Tokyo 140-0011 (Japan); Mizuno, T. [Department of Management Science, College of Engineering, Tamagawa University, Machida, Tokyo 194-8610 (Japan)

    2014-02-15

    Progress in the kinetic modeling of particle dynamics in H{sup −} negative ion source plasmas and their comparisons with experiments are reviewed, and discussed with some new results. Main focus is placed on the following two topics, which are important for the research and development of large negative ion sources and high power H{sup −} ion beams: (i) Effects of non-equilibrium features of EEDF (electron energy distribution function) on H{sup −} production, and (ii) extraction physics of H{sup −} ions and beam optics.

  17. Ion induced high energy electron emission from copper

    Energy Technology Data Exchange (ETDEWEB)

    Ruano, G. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)], E-mail: gdruano@ceride.gov.ar; Ferron, J. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina); Departamento de Ingenieria de Materiales, Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)

    2008-11-15

    We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He{sup +}, Ne{sup +} and Ar{sup +}) and Li{sup +} ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

  18. Kinetic Simulation of Fast Electron Transport with Ionization Effects and Ion Acceleration

    International Nuclear Information System (INIS)

    Robinson, A. P. L.; Bell, A. R.; Kingham, R. J.

    2005-01-01

    The generation of relativistic electrons and multi-MeV ions is central to ultra intense (> 1018Wcm-2) laser-solid interactions. The production of energetic particles by lasers has a number of potential applications ranging from Fast Ignition ICF to medicine. In terms of the relativistic (fast) electrons the areas of interest can be divided into three areas. Firstly there is the absorption of laser energy into fast electrons and MeV ions. Secondly there is the transport of fast electrons through the solid target. Finally there is a transduction stage, where the fast electron energy is imparted. This may range from being the electrostatic acceleration of ions at a plasma-vacuum interface, to the heating of a compressed core (as in Fast Ignitor ICF).We have used kinetic simulation codes to study the transport stage and electrostatic ion acceleration. (Author)

  19. Direct acceleration of ions to low and medium energies by a crossed-laser-beam configuration

    Directory of Open Access Journals (Sweden)

    Yousef I. Salamin

    2011-07-01

    Full Text Available Calculations show that 10 keV helium and carbon ions, injected midway between two identical 1 TW-power crossed laser beams of radial polarization, can be accelerated in vacuum to energies of utility in ion lithography. As examples, identical laser beams, crossed at 10° and focused to waist radii of 7.42  μm, accelerate He^{2+} and C^{6+} ions to average kinetic energies near 75 and 165 keV over distances averaging less than 7 and 6 mm, respectively. The spread in kinetic energy in both cases is less than 1% and the particle average angular deflection is less than 7 mrad. More energy-demanding industrial applications require higher-power laser beams for their direct ion laser acceleration.

  20. Monte Carlo simulation of kinetic electron emission from metal due to impact of heavy ions

    International Nuclear Information System (INIS)

    Kawata, J.; Ohya, K.

    1999-01-01

    A Monte Carlo simulation is performed for study of the dependence of kinetic electron emission on nuclear charge of projectile Z 1 , using the nonlinear response theory with the density-functional (DF) formalism to calculate electron excitation cross section. The kinetic yield, energy distribution, excitation depth distribution and emission statistics of emitted electrons showed clear Z 1 oscillations, however, the Z 1 oscillations of them are different from that of the inelastic stopping power, in particular for high Z 1 , due to large elastic energy loss of the ions and secondary cascade process of primary excited electrons within the solid. For high Z 1 , the linear relationship does not exist between them and the inelastic stopping power, although they are closely related to it. The emission of high-energy primary electrons excited by the ion within shallow depth without experiencing the secondary cascade process, results in the Z 1 dependence in the energy distribution, excitation depth distribution and emission statistics of emitted electrons

  1. Calmodulin-lanthanide ion exchange kinetics

    International Nuclear Information System (INIS)

    Buccigross, J.; O'Donnell, C.; Nelson, D.

    1985-01-01

    A flow dialysis apparatus suitable for the study of high affinity metal binding proteins has been utilized to study calmodulin-metal exchange kinetics. Calmodulin labeled with Eu-155 and Gd-153 was dialyzed against buffer containing various competing metal ions. The rate of metal exchange was monitored by a gamma-ray scintillation detector. The kinetics of exchange are first order, and the rates fall into two categories: Ca (II) and CD (II) in one, and the lanthanides Eu (III), Gd (III), and La (III) in the other

  2. Rate theory of solvent exchange and kinetics of Li(+) - BF4 (-)/PF6 (-) ion pairs in acetonitrile.

    Science.gov (United States)

    Dang, Liem X; Chang, Tsun-Mei

    2016-09-07

    In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li(+) and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li(+) in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li(+)-[BF4] and Li(+)-[PF6] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li(+). We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li(+)-[BF4] and Li(+)-[PF6] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.

  3. Ion exchange kinetics of alkaline earths on Zr(IV) arsenosilicate cation exchanger

    International Nuclear Information System (INIS)

    Varshney, K.G.; Agrawal, S.; Varshney, K.

    1984-01-01

    A new approach based on the Nernst-Planck equations was applied to study the ion exchange kinetics for the exchange reactions of Mg(II), Ca(II), Sr(II) and Ba(II) with H + -ions at various temperatures on the zirconium(IV) arsenosilicate phase. Under the conditions of particle diffusion, the rate of exchange was found to be independent of the metal ion concentration at and above 0.1 M in aqueous medium. Energy and entropy of activation were determined and found to vary linearly with the ionic radii and mobilities of alkaline earths, a unique feature observed for an inorganic ion exchanger. The results are useful for predicting the ion exchange processes occurring on the surface of an inorganic material of the type studied. (author)

  4. High energy structures in heavy ion collisions: a multiphonon description

    International Nuclear Information System (INIS)

    Chomaz, P.; Blumenfeld, Y.; Frascaria, N.

    1984-01-01

    Energy spectra of fragments from the 36 Ar + 208 Pb reaction at 11 MeV/n exhibit structures at high excitation energies. These structures are interpreted in terms of target multi-phonon excitations built from giant resonances. The importance of such processes for the kinetic energy dissipation in heavy ion collisions is emphasized

  5. Kinetic Framework for the Magnetosphere-Ionosphere-Plasmasphere-Polar Wind System: Modeling Ion Outflow

    Science.gov (United States)

    Schunk, R. W.; Barakat, A. R.; Eccles, V.; Karimabadi, H.; Omelchenko, Y.; Khazanov, G. V.; Glocer, A.; Kistler, L. M.

    2014-12-01

    A Kinetic Framework for the Magnetosphere-Ionosphere-Plasmasphere-Polar Wind System is being developed in order to provide a rigorous approach to modeling the interaction of hot and cold particle interactions. The framework will include ion and electron kinetic species in the ionosphere, plasmasphere and polar wind, and kinetic ion, super-thermal electron and fluid electron species in the magnetosphere. The framework is ideally suited to modeling ion outflow from the ionosphere and plasmasphere, where a wide range for fluid and kinetic processes are important. These include escaping ion interactions with (1) photoelectrons, (2) cusp/auroral waves, double layers, and field-aligned currents, (3) double layers in the polar cap due to the interaction of cold ionospheric and hot magnetospheric electrons, (4) counter-streaming ions, and (5) electromagnetic wave turbulence. The kinetic ion interactions are particularly strong during geomagnetic storms and substorms. The presentation will provide a brief description of the models involved and discuss the effect that kinetic processes have on the ion outflow.

  6. Nanometer-size surface modification produced by single, low energy, highly charged ions

    International Nuclear Information System (INIS)

    Stockli, M.P.

    1994-01-01

    Atomically flat surfaces of insulators have been bombarded with low energy, highly charged ions to search for nanometer-size surface modifications. It is expected that the high electron deficiency of highly charged ions will capture and/or remove many of the insulator's localized electrons when impacting on an insulating surface. The resulting local electron deficiency is expected to locally disintegrate the insulator through a open-quotes Coulomb explosionclose quotes forming nanometer-size craters. Xe ions with charge states between 10+ and 45+ and kinetic energies between 0 and 10 keV/q were obtained from the KSU-CRYEBIS, a CRYogenic Electron Beam Ion Source and directed onto various insulating materials. Mica was favored as target material as atomically flat surfaces can be obtained reliably through cleaving. However, the authors observations with an atomic force microscope have shown that mica tends to defoliate locally rather than disintegrate, most likely due to the small binding forces between adjacent layers. So far the authors measurements indicate that each ion produces one blister if the charge state is sufficiently high. The blistering does not seem to depend very much on the kinetic energy of the ions

  7. Fully-kinetic Ion Simulation of Global Electrostatic Turbulent Transport in C-2U

    Science.gov (United States)

    Fulton, Daniel; Lau, Calvin; Bao, Jian; Lin, Zhihong; Tajima, Toshiki; TAE Team

    2017-10-01

    Understanding the nature of particle and energy transport in field-reversed configuration (FRC) plasmas is a crucial step towards an FRC-based fusion reactor. The C-2U device at Tri Alpha Energy (TAE) achieved macroscopically stable plasmas and electron energy confinement time which scaled favorably with electron temperature. This success led to experimental and theoretical investigation of turbulence in C-2U, including gyrokinetic ion simulations with the Gyrokinetic Toroidal Code (GTC). A primary objective of TAE's new C-2W device is to explore transport scaling in an extended parameter regime. In concert with the C-2W experimental campaign, numerical efforts have also been extended in A New Code (ANC) to use fully-kinetic (FK) ions and a Vlasov-Poisson field solver. Global FK ion simulations are presented. Future code development is also discussed.

  8. Kinetic modeling of auroral ion outflows observed by the VISIONS sounding rocket

    Science.gov (United States)

    Albarran, R. M.; Zettergren, M. D.

    2017-12-01

    The VISIONS (VISualizing Ion Outflow via Neutral atom imaging during a Substorm) sounding rocket was launched on Feb. 7, 2013 at 8:21 UTC from Poker Flat, Alaska, into an auroral substorm with the objective of identifying the drivers and dynamics of the ion outflow below 1000km. Energetic ion data from the VISIONS polar cap boundary crossing show evidence of an ion "pressure cooker" effect whereby ions energized via transverse heating in the topside ionosphere travel upward and are impeded by a parallel potential structure at higher altitudes. VISIONS was also instrumented with an energetic neutral atom (ENA) detector which measured neutral particles ( 50-100 eV energy) presumably produced by charge-exchange with the energized outflowing ions. Hence, inferences about ion outflow may be made via remotely-sensing measurements of ENAs. This investigation focuses on modeling energetic outflowing ion distributions observed by VISIONS using a kinetic model. This kinetic model traces large numbers of individual particles, using a guiding-center approximation, in order to allow calculation of ion distribution functions and moments. For the present study we include mirror and parallel electric field forces, and a source of ion cyclotron resonance (ICR) wave heating, thought to be central to the transverse energization of ions. The model is initiated with a steady-state ion density altitude profile and Maxwellian velocity distribution characterizing the initial phase-space conditions for multiple particle trajectories. This project serves to advance our understanding of the drivers and particle dynamics in the auroral ionosphere and to improve data analysis methods for future sounding rocket and satellite missions.

  9. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    Science.gov (United States)

    Cernusca, S.; Winter, HP.; Aumayr, F.; Díez Muiño, R.; Juaristi, J. I.

    2003-04-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to "projectile molecular effects" (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials.

  10. Accelerating action of stresses on crystallization kinetics in silicon ion-implanted layers during pulsed heating

    International Nuclear Information System (INIS)

    Aleksandrov, L.N.

    1985-01-01

    Numerical simulation of the effect of stressed in ion-implanted layers on kinetics of amorphous phase transformations is performed. The suggested model of accounting stresses including concentration ones is based on the locality of action of interstitial addition atoms and on general structural inhomogeneity of amorphous semiconductor leading to the formation of areas of the facilitated phase transition. Accounting of effect of energy variation of silicon atoms interaction on probability of displacement events and atoms building in lattice points or atomic bonds disintegration allows one to trace the accelerating action of introduced by ion implantation stresses on the kinetics of layer crystallization during pulsed heating

  11. The kinetics and thermodynamics of adsorption of heavy metal ions ...

    African Journals Online (AJOL)

    Titanium-Pillared and Un-Pillared bentonite clays were studied in order to evaluate the thermodynamics and kinetics of heavy metal ion removal from aqueous solutions. The results showed that the maximum sorption of Cu, Cd, Hg and Pb ions occurred within 30 minutes. A pseudo-second order kinetic model was used to ...

  12. Generation of intense, high-energy ion pulses by magnetic compression of ion rings

    International Nuclear Information System (INIS)

    Kapetanakos, C.A.

    1981-01-01

    A system based on the magnetic compression of ion rings, for generating intense (High-current), high-energy ion pulses that are guided to a target without a metallic wall or an applied external magnetic field includes a vacuum chamber; an inverse reflex tetrode for producing a hollow ion beam within the chamber; magnetic coils for producing a magnetic field, bo, along the axis of the chamber; a disc that sharpens a magnetic cusp for providing a rotational velocity to the beam and causing the beam to rotate; first and second gate coils for producing fast-rising magnetic field gates, the gates being spaced apart, each gate modifying a corresponding magnetic mirror peak (Near and far peaks) for trapping or extracting the ions from the magnetic mirror, the ions forming a ring or layer having rotational energy; a metal liner for generating by magnetic flux compression a high, time-varying magnetic field, the time-varying magnetic field progressively increasing the kinetic energy of the ions, the magnetic field from the second gate coil decreasing the far mirror peak at the end of the compression for extracting the trapped rotating ions from the confining mirror; and a disc that sharpens a magnetic half-cusp for increasing the translational velocity of the ion beam. The system utilizes the self-magnetic field of the rotating, propagating ion beam to prevent the beam from expanding radially upon extraction

  13. Local energy equation for two-electron atoms and relation between kinetic energy and electron densities

    International Nuclear Information System (INIS)

    March, N.H.

    2002-08-01

    In early work, Dawson and March [J. Chem. Phys. 81, 5850 (1984)] proposed a local energy method for treating both Hartree-Fock and correlated electron theory. Here, an exactly solvable model two-electron atom with pure harmonic interactions is treated in its ground state in the above context. A functional relation between the kinetic energy density t(r) at the origin r=0 and the electron density p(r) at the same point then emerges. The same approach is applied to the Hookean atom; in which the two electrons repel with Coulombic energy e 2 /r 12 , with r 12 the interelectronic separation, but are still harmonically confined. Again the kinetic energy density t(r) is the focal point, but now generalization away from r=0 is also effected. Finally, brief comments are added about He-like atomic ions in the limit of large atomic number. (author)

  14. Kinetic Alfven wave with density variation and loss-cone distribution function of multi-ions in PSBL region

    Science.gov (United States)

    Tamrakar, Radha; Varma, P.; Tiwari, M. S.

    2018-05-01

    Kinetic Alfven wave (KAW) generation due to variation of loss-cone index J and density of multi-ions (H+, He+ and O+) in the plasma sheet boundary layer region (PSBL) is investigated. Kinetic approach is used to derive dispersion relation of wave using Vlasov equation. Variation of frequency with respect to wide range of k⊥ρi (where k⊥ is wave vector across the magnetic field, ρi is gyroradius of ions and i denotes H+, He+ and O+ ions) is analyzed. It is found that each ion gyroradius and number density shows different effect on wave generation with varying width of loss-cone. KAW is generated with multi-ions (H+, He+ and O+) over wide regime for J=1 and shows dissimilar effect for J=2. Frequency is reduced with increasing density of gyrating He+ and O+ ions. Wave frequency is obtained within the reported range which strongly supports generation of kinetic Alfven waves. A sudden drop of frequency is also observed for H+ and He+ ion which may be due to heavy penetration of these ions through the loss-cone. The parameters of PSBL region are used for numerical calculation. The application of these results are in understanding the effect of gyrating multi-ions in transfer of energy and Poynting flux losses from PSBL region towards ionosphere and also describing the generation of aurora.

  15. Adsorption of Pb(II) ions from aqueous solution by native and activated bentonite: Kinetic, equilibrium and thermodynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Kul, Ali Riza [Yuzuncu Yil University, Faculty of Art and Science, Department of Chemistry, 65080 Van (Turkey); Koyuncu, Huelya, E-mail: hkoyuncu@yyu.edu.tr [Forensic Medicine Foundation, Felek Street No. 45, 06300 Kecioren, Ankara (Turkey)

    2010-07-15

    In this study, the adsorption kinetics, equilibrium and thermodynamics of Pb(II) ions on native (NB) and acid activated (AAB) bentonites were examined. The specific surface areas, pore size and pore-size distributions of the samples were fully characterized. The adsorption efficiency of Pb(II) onto the NB and AAB was increased with increasing temperature. The kinetics of adsorption of Pb(II) ions was discussed using three kinetic models, the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model. The experimental data fitted very well the pseudo-second-order kinetic model. The initial sorption rate and the activation energy were also calculated. The activation energy of the sorption was calculated as 16.51 and 13.66 kJ mol{sup -1} for NB and AAB, respectively. Experimental results were also analysed by the Langmuir, Freundlich and Dubinin-Redushkevich (D-R) isotherm equations at different temperatures. R{sub L} separation factor for Langmuir and the n value for Freundlich isotherm show that Pb(II) ions are favorably adsorbed by NB and AAB. Thermodynamic quantities such as Gibbs free energy ({Delta}G), the enthalpy ({Delta}H) and the entropy change of sorption ({Delta}S) were determined as about -5.06, 10.29 and 0.017 kJ mol{sup -1} K{sup -1}, respectively for AAB. It was shown that the sorption processes were an endothermic reactions, controlled by physical mechanisms and spontaneously.

  16. Coherent production of high-energy photons and π mesons in heavy ion reactions

    International Nuclear Information System (INIS)

    Batkin, I.S.; Kopytin, I.V.

    1986-01-01

    A microscopic model of high-energy photon and pion production processes in collision of multicharged ions with kinetic energy of relative motion from 40 to 100 MeV per nucleon was constructed not using fitting parameters

  17. Electron energy recovery system for negative ion sources

    International Nuclear Information System (INIS)

    Dagenhart, W.K.; Stirling, W.L.

    1982-01-01

    An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90* to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy

  18. Kinetic ion exchange studies in ultramarines by the radioactive tracer method; Etudes cinetiques d'echanges d'ions dans les outremers par la technique des traceurs radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    May, S; Goenvec, H; Pinte, G [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The possibility of ion exchanges in various ultramarines has been studied in the aqueous phase. The kinetics of the exchange reactions is followed by studying the behaviour of a radioactive ion, either in the solution of the exchanging salt or in the ultramarine itself. The sodium in the make-up of the ultramarine, is found to exchange with various ions in solution. The reaction speeds appear to be governed by a diffusion process inside the grains of ultramarine. The diffusion coefficients and the activation energies are determined for the exchanges studied. Several exchange studies were carried out in an organic medium. The kinetics of ion exchange is also investigated in ultramarines from which most of the constituent sulphur has been eliminated. The results obtained in these ultramarines are compared with the exchange kinetics of the same ions in ordinary ultramarine. (author) [French] Nous avons etudie la possibilite d'echanges ioniques dans differents outremers, en phase aqueuse. L'etude cinetique des reactions d'echanges est suivie en etudiant le comportement d'ion radioactif, soit dans la solution du sel echangeant, soit dans l'outremer lui-meme. C'est le sodium de constitution de l'outremer qui s'echange avec differents ions en solution. Les vitesses de reactions semblent etre controlees par un processus de diffusion a l'interieur des grains d'outremer. Les coefficients de diffusion et les energies d'activation sont determines pour les echanges etudies. Quelques etudes sont realisees en milieu organique ou quelques echanges ont ete etudies. La cinetique d'echange d'ions est egalement etudie dans des outremers dans lesquels la majorite du soufre de constitution a ete eliminee. On compare les resultats obtenus dans ces outremers avec les cinetiques d'echanges des memes ions dans l'outremer ordinaire. (auteur)

  19. Interaction of low-energy highly charged ions with matter

    International Nuclear Information System (INIS)

    Ginzel, Rainer

    2010-01-01

    The thesis presented herein deals with experimental studies of the interaction between highly charged ions and neutral matter at low collision energies. The energy range investigated is of great interest for the understanding of both charge exchange reactions between ions comprising the solar wind and various astrophysical gases, as well as the creation of near-surface nanostructures. Over the course of this thesis an experimental setup was constructed, capable of reducing the kinetic energy of incoming ions by two orders of magnitude and finally focussing the decelerated ion beam onto a solid or gaseous target. A coincidence method was employed for the simultaneous detection of photons emitted during the charge exchange process together with the corresponding projectile ions. In this manner, it was possible to separate reaction channels, whose superposition presumably propagated large uncertainties and systematic errors in previous measurements. This work has unveiled unexpectedly strong contributions of slow radiative decay channels and clear evidence of previously only postulated decay processes in charge exchange-induced X-ray spectra. (orig.)

  20. Kinetic electron emission from highly oriented pyrolytic graphite surfaces induced by singly charged ions

    CERN Document Server

    Cernusca, S; Winter, H; Aumayr, F; Loerincik, J; Sroubek, Z

    2002-01-01

    We present total electron yields determined by current measurements for normal impact of H sup + , H sub 2 sup + , H sub 3 sup + , C sup + , N sup + and O sup + ions (E<=10 keV) on a clean highly oriented pyrolytic graphite surface. The kinetic energy of the projectiles has been varied from near threshold up to 10 keV. By comparing the results to similar data obtained for a polycrystalline Au surface the role of different target properties for kinetic electron emission can be analysed.

  1. Energy dependence of ion guiding through nanocapillaries

    International Nuclear Information System (INIS)

    Schiessl, K.; Lemell, C.; Burgdoerfer, J.; Toekesi, K.

    2008-01-01

    Complete text of publication follows. In this work, we model the transmission of Ne 7+ ions with varying kinetic energies ranging from 2 to 9 keV through Polyethyleneterephthalate (PET) nanocapillaries with a diameter of 200 nm (see Fig. 1). We have simulated the ion transmission through insulating nanocapillaries using a mean-field classical-transport theory (see Fig. 2.). Ion trajectories are propagated in the combined fields of charges deposited on the capillary wall, their polarization charges, the projectile image charge, and the macroscopic field from neighboring capillaries. The simulation avoids any freely adjustable parameters in order to be predictive and to provide qualitative insights into underlying mechanisms. We have varied projectile energy and angle of incidence and have tested different models of dielectric shielding. Best agreement with experimental data is found for dielectrically screened surfaces charges. Response and transport employs linear response only. Reasonable agreement with data could be found employing only macroscopic material parameters of PET like dielectric constant, surface and bulk conductivity

  2. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    International Nuclear Information System (INIS)

    Cernusca, S.; Winter, H.P.; Aumayr, F.; Diez Muino, R.; Juaristi, J.I.

    2003-01-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy <10 keV) on atomically clean surfaces of carbon-fiber inforced graphite used as first-wall armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to 'projectile molecular effects' (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials

  3. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    CERN Document Server

    Cernusca, S; Aumayr, F; Diez-Muino, R; Juaristi, J I

    2003-01-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy <10 keV) on atomically clean surfaces of carbon-fiber inforced graphite used as first-wall armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to 'projectile molecular effects' (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials.

  4. Kinetic theory for electron dynamics near a positive ion

    International Nuclear Information System (INIS)

    Wrighton, Jeffrey M; Dufty, James W

    2008-01-01

    A theoretical description of time correlation functions for electron properties in the presence of a positive ion of charge number Z is given. The simplest case of an electron gas distorted by a single ion is considered. A semi-classical representation with a regularized electron–ion potential is used to obtain a linear kinetic theory that is asymptotically exact at short times. This Markovian approximation includes all initial (equilibrium) electron–electron and electron–ion correlations through renormalized pair potentials. The kinetic theory is solved in terms of single-particle trajectories of the electron–ion potential and a dielectric function for the inhomogeneous electron gas. The results are illustrated by a calculation of the autocorrelation function for the electron field at the ion. The dependence on charge number Z is shown to be dominated by the bound states of the effective electron–ion potential. On this basis, a very simple practical representation of the trajectories is proposed and shown to be accurate over a wide range including strong electron–ion coupling. This simple representation is then used for a brief analysis of the dielectric function for the inhomogeneous electron gas

  5. Plasma kinetics around a dust grain in an ion flow

    International Nuclear Information System (INIS)

    Maiorov, S.A.; Vladimirov, S.V.; Cramer, N.F.

    2000-01-01

    Full text: In a typical laboratory discharge, dust particles are negatively charged and usually levitate in the sheath or pre-sheath region under the balance of gravitational, electrostatic (due to the sheath electric field) and plasma (such as the ion drag) forces. The ion flow provides not only a direct (dragging) influence, but is also responsible for the generation of associated collective plasma processes which can strongly affect the vertical arrangement of the dust grains. The complete problem of the plasma dynamics around a macroscopic body in the presence of plasma flows is highly nonlinear and therefore its numerical analysis is of major importance. Among various numerical methods, direct integration of the equations of motion of the plasma particles represents a numerical experiment whose significance approaches experiments in the laboratory. Here, we present for the first time the results of a self-consistent molecular dynamics (MD) three-dimensional (3D) simulation of the kinetics of plasma particles (electrons and ions) around a dust grain, taking into account the dust charging. The core of the method includes consideration of the time evolution of the system consisting of positively ('ions') and negatively ('electrons') charged particles confined in a simulation box together with a macroscopic absorbing grain ('dust particle') with infinite mass and an initial (negative) charge. The ions are introduced in the system as a uniform flow defined by its Mach number and the ion temperature. The paths of the ions and electrons are determined through numerical integration of the equations of motion. We demonstrate that the plasma kinetics around a dust grain in the presence of an ion flow involves a strong ion focusing behind the grain. We have also confirmed that the most important of the processes involved is the ion time-scale; the kinetics of the electrons follows a Boltzmann distribution with good agreement. We note that the time constraints involved

  6. Kinetics and thermodynamics of aluminium dissolution in 1.0M sulphuric acid containing chloride ions

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Gaber, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt)]. E-mail: ashrafmoustafa@yahoo.com; Abd-El-Nabey, B.A. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt); Sidahmed, I.M. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt); El-Zayady, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt); Saadawy, M. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt)

    2006-08-01

    The dissolution of aluminium in 1M sulphuric acid solutions containing different chloride ion concentrations (0.01-0.06M) were studied at 25, 30, 35 and 40deg. C using electrochemical impedance spectroscopy (EIS) technique and polarization curves measurements. The kinetic rate equation, under the experimental condition described, was derived and found to verify the following relationship:V=k{sub obs}K{sub 2}C{sub Cl{sup -}}{sup n}1+K{sub 2}C{sub Cl{sup -}}{sup n}where V is the corrosion rate, k{sub obs} and K{sub 2} are the dissolution rate constant of aluminium oxide-chloride complex and the equilibrium constant of chloride ions adsorbed at aluminium oxide surface, respectively. The kinetic and thermodynamic energy parameters were calculated and their values indicate that chloride ions are chemisorbed onto the aluminium oxide surface and the formation of oxide-chloride complex is the rate-determining step.

  7. Rate theory of solvent exchange and kinetics of Li+ − BF4−/PF6− ion pairs in acetonitrile

    International Nuclear Information System (INIS)

    Dang, Liem X.; Chang, Tsun-Mei

    2016-01-01

    In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li + and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li + in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li + -[BF 4 ] and Li + -[PF 6 ] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li + . We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li + -[BF 4 ] and Li + -[PF 6 ] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems.

  8. Kinetics of ion exchange in the chelating resin Dowex A-1

    International Nuclear Information System (INIS)

    Matsuzuru, Hideo; Wadachi, Yoshiki

    1975-01-01

    The kinetics of ion exchanges of Ag + , Zn 2+ and Cr 3+ at extremely low concentrations on the chelating resin Dowex A-1 has been studied by means of finite volume method. The rate of exchanges for both Ag + and Zn 2+ is dependent on the ionic strength, particle size of the resin and reaction temperature. At higher ionic strength (0.1 - 0.05) the kinetics is controlled by particle diffusion, whereas at lower ionic one (0.01 - 0.001) film diffusion is predominant. The apparent activation energy obtained is 3.84 kcal/mol for Ag + and 3.91 kcal/mol for Zn 2+ . The exchange rate of Cr 3+ obeys a first-order rate equation independent of the ionic strength and particle size of the resin. The apparent activation energy is 15.5 kcal/mol. These results support the view that the rate-determining step of this reaction is chelate formation reaction. (auth.)

  9. Kinetic studies of uranyl ion adsorption on acrylonitrile (AN)/polyethylene glycol (PEG) interpenetrating networks (IPN)

    International Nuclear Information System (INIS)

    Aycik, G.A.; Gurellier, R.

    2004-01-01

    Full text: The kinetics of the adsorption of uranyl ions on amidoximated acrylonitrile (AN)/ polyethylene glycol (PEG) interpenetrating network (IPNs) from aqueous solutions was studied as a function of time and temperature. The IPNs were prepared by irradiation initiated gamma polymerisation using Co-60 gamma source. Adsorption capacities were performed for definite uranyl ion concentrations of 1x10 -2 M and at four different temperatures as 290K, 298K, 308K and 318K by gamma spectrometer. Adsorption time was increased from zero to 48 hours. The results indicate that adsorption capacity increases linearly with increasing temperature. Temperature and agitation hardly influence equilibrium and kinetics and decreasing of temperature results in a slightly greater time to reach equilibrium. The adsorption of uranyl ions has been studied in a multi step mechanism processes thus comparing chemical sorption and diffusion sorption processes. The experimental data was analysed using various kinetic models to determine the best-fit equation for the adsorption mechanisms. However, it was shown that all models, in general according to the reaction time and uranyl ion concentration in the solution, could describe the adsorption of uranyl ion onto amidoximated IPN, the adsorption kinetics was best described by zeroth order and intraparticle diffusion model whereas that of in increasing time by pseudo first and pseudo second order response respectively. External-intraparticle diffusion and zeroth order process in the IPN structure is proposed as a mass transfer mechanism and the results indicate a diffusion-controlled process. The Mean Activation Energy Of Uranyl Ions Adsorption Was Found As 4,1 Kj/Mole By Using Arrhenius Equation. The Rate Constant, The Equilibrium Adsorption Capacity And The Initial Adsorption Rate Were Calculated For All Models At Each Temperature. Kinetic Parameters Of All Models And The Normalized Standard Deviations Between The Measured And Predicted

  10. Low-energy irradiation effects of gas cluster ion beams

    International Nuclear Information System (INIS)

    Houzumi, Shingo; Takeshima, Keigo; Mochiji, Kozo; Toyoda, Noriaki; Yamada, Isao

    2007-01-01

    A cluster-ion irradiation system with cluster-size selection has been developed to study the effects of the cluster size for surface processes using cluster ions. A permanent magnet with a magnetic field of 1.2 T is installed for size separation of large cluster ions. Trace formations at HOPG surface by the irradiation with size-selected Ar-cluster ions under acceleration energy of 30 keV were investigated by a scanning tunneling microscopy. Generation behavior of the crater-like traces is strongly affected by the number of constituent atoms (cluster size) of the irradiating cluster ion. When the incident cluster ion is composed of 100-3000 atoms, crater-like traces are observed on the irradiated surfaces. In contrast, such traces are not observed at all with the irradiation of the cluster-ions composed of over 5000 atoms. Such the behavior is discussed on the basis of the kinetic energy per constituent atom of the cluster ion. To study GCIB irradiation effects against macromolecule, GCIB was irradiated on DNA molecules absorbed on graphite surface. By the GCIB irradiation, much more DNA molecules was sputtered away as compared with the monomer-ion irradiation. (author)

  11. A thermal extrapolation method for the effective temperatures and internal energies of activated ions

    Science.gov (United States)

    Meot-Ner (Mautner), Michael; Somogyi, Árpád

    2007-11-01

    The internal energies of dissociating ions, activated chemically or collisionally, can be estimated using the kinetics of thermal dissociation. The thermal Arrhenius parameters can be combined with the observed dissociation rate of the activated ions using kdiss = Athermalexp(-Ea,thermal/RTeff). This Arrhenius-type relation yields the effective temperature, Teff, at which the ions would dissociate thermally at the same rate, or yield the same product distributions, as the activated ions. In turn, Teff is used to calculate the internal energy of the ions and the energy deposited by the activation process. The method yields an energy deposition efficiency of 10% for a chemical ionization proton transfer reaction and 8-26% for the surface collisions of various peptide ions. Internal energies of ions activated by chemical ionization or by gas phase collisions, and of ions produced by desorption methods such as fast atom bombardment, can be also evaluated. Thermal extrapolation is especially useful for ion-molecule reaction products and for biological ions, where other methods to evaluate internal energies are laborious or unavailable.

  12. Tandem mass spectrometry at low kinetic energy

    International Nuclear Information System (INIS)

    Cooks, R.G.; Hand, O.W.

    1987-01-01

    Recent progress in mass spectrometry, as applied to molecular analysis, is reviewed with emphasis on tandem mass spectrometry. Tandem instruments use multiple analyzers (sector magnets, quadrupole mass filters and time-of-flight devices) to select particular molecules in ionic form, react them in the gas-phase and then record the mass, momenta or kinetic energies of their products. The capabilities of tandem mass spectrometry for identification of individual molecules or particular classes of compounds in complex mixtures are illustrated. Several different types of experiments can be run using a tandem mass spectrometer; all share the feature of sifting the molecular mixture being analyzed on the basis of chemical properties expressed in terms of ionic mass, kinetic energy or charge state. Applications of mass spectrometry to biological problems often depend upon desorption methods of ionization in which samples are bombarded with particle beams. Evaporation of preformed charged species from the condensed phase into the vacuum is a particularly effective method of ionization. It is suggested that the use of accelerator mass spectrometers be extended to include problems of molecular analysis. In such experiments, low energy tandem mass spectrometry conducted in the eV or keV range of energies, would be followed by further characterization of the production ion beam using high selective MeV collision processes

  13. RNA folding: structure prediction, folding kinetics and ion electrostatics.

    Science.gov (United States)

    Tan, Zhijie; Zhang, Wenbing; Shi, Yazhou; Wang, Fenghua

    2015-01-01

    Beyond the "traditional" functions such as gene storage, transport and protein synthesis, recent discoveries reveal that RNAs have important "new" biological functions including the RNA silence and gene regulation of riboswitch. Such functions of noncoding RNAs are strongly coupled to the RNA structures and proper structure change, which naturally leads to the RNA folding problem including structure prediction and folding kinetics. Due to the polyanionic nature of RNAs, RNA folding structure, stability and kinetics are strongly coupled to the ion condition of solution. The main focus of this chapter is to review the recent progress in the three major aspects in RNA folding problem: structure prediction, folding kinetics and ion electrostatics. This chapter will introduce both the recent experimental and theoretical progress, while emphasize the theoretical modelling on the three aspects in RNA folding.

  14. Spectator Ions ARE Important! A Kinetic Study of the Copper-Aluminum Displacement Reaction

    Science.gov (United States)

    Sobel, Sabrina G.; Cohen, Skyler

    2010-01-01

    Surprisingly, spectator ions are responsible for unexpected kinetics in the biphasic copper(II)-aluminum displacement reaction, with the rate of reaction dependent on the identity of the otherwise ignored spectator ions. Application of a published kinetic analysis developed for a reaction between a rotating Al disk and a Cu(II) ion solution to the…

  15. Study of uranium dioxyde sputtering induced by multicharged heavy ions at low and very low kinetic energy: projectile charge effect; Etude de la pulverisation du dioxyde d'uranium induite par des ions lourds multicharges de basse et tres basse energie cinetique; effet de la charge du projectile

    Energy Technology Data Exchange (ETDEWEB)

    Haranger, F

    2003-12-01

    Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)

  16. Sinusoidal voltage protocols for rapid characterisation of ion channel kinetics.

    Science.gov (United States)

    Beattie, Kylie A; Hill, Adam P; Bardenet, Rémi; Cui, Yi; Vandenberg, Jamie I; Gavaghan, David J; de Boer, Teun P; Mirams, Gary R

    2018-03-24

    Ion current kinetics are commonly represented by current-voltage relationships, time constant-voltage relationships and subsequently mathematical models fitted to these. These experiments take substantial time, which means they are rarely performed in the same cell. Rather than traditional square-wave voltage clamps, we fitted a model to the current evoked by a novel sum-of-sinusoids voltage clamp that was only 8 s long. Short protocols that can be performed multiple times within a single cell will offer many new opportunities to measure how ion current kinetics are affected by changing conditions. The new model predicts the current under traditional square-wave protocols well, with better predictions of underlying currents than literature models. The current under a novel physiologically relevant series of action potential clamps is predicted extremely well. The short sinusoidal protocols allow a model to be fully fitted to individual cells, allowing us to examine cell-cell variability in current kinetics for the first time. Understanding the roles of ion currents is crucial to predict the action of pharmaceuticals and mutations in different scenarios, and thereby to guide clinical interventions in the heart, brain and other electrophysiological systems. Our ability to predict how ion currents contribute to cellular electrophysiology is in turn critically dependent on our characterisation of ion channel kinetics - the voltage-dependent rates of transition between open, closed and inactivated channel states. We present a new method for rapidly exploring and characterising ion channel kinetics, applying it to the hERG potassium channel as an example, with the aim of generating a quantitatively predictive representation of the ion current. We fitted a mathematical model to currents evoked by a novel 8 second sinusoidal voltage clamp in CHO cells overexpressing hERG1a. The model was then used to predict over 5 minutes of recordings in the same cell in response to

  17. Effect of operating parameters on indium (III) ion removal by iron electrocoagulation and evaluation of specific energy consumption

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Wei-Lung, E-mail: wlchou0388@hotmail.com [Department of Safety, Health and Environmental Engineering, Hungkuang University, Sha-Lu, Taichung 433, Taiwan (China); Wang, Chih-Ta [Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, Tainan Hsien 717, Taiwan (China); Huang, Kai-Yu [Department of Safety, Health and Environmental Engineering, Hungkuang University, Sha-Lu, Taichung 433, Taiwan (China)

    2009-08-15

    The aim of this study is to investigate the effects of operating parameters on the specific energy consumption and removal efficiency of synthetic wastewater containing indium (III) ions by electrocoagulation in batch mode using an iron electrode. Several parameters, including different electrode pairs, supporting electrolytes, initial concentration, pH variation, and applied voltage, were investigated. In addition, the effects of applied voltage, supporting electrolyte, and initial concentration on indium (III) ion removal efficiency and specific energy consumption were investigated under the optimum balance of reasonable removal efficiency and relative low energy consumption. Experiment results indicate that a Fe/Al electrode pair is the most efficient choice of the four electrode pairs in terms of energy consumption. The optimum supporting electrolyte concentration, initial concentration, and applied voltage were found to be 100 mg/l NaCl, 20 mg/l, and 20 V, respectively. A higher pH at higher applied voltage (20 or 30 V) enhanced the precipitation of indium (III) ion as insoluble indium hydroxide, which improved the removal efficiency. Results from the indium (III) ion removal kinetics show that the kinetics data fit the pseudo second-order kinetic model well. Finally, the composition of the sludge produced was characterized with energy dispersion spectra (EDS).

  18. Effect of operating parameters on indium (III) ion removal by iron electrocoagulation and evaluation of specific energy consumption

    International Nuclear Information System (INIS)

    Chou, Wei-Lung; Wang, Chih-Ta; Huang, Kai-Yu

    2009-01-01

    The aim of this study is to investigate the effects of operating parameters on the specific energy consumption and removal efficiency of synthetic wastewater containing indium (III) ions by electrocoagulation in batch mode using an iron electrode. Several parameters, including different electrode pairs, supporting electrolytes, initial concentration, pH variation, and applied voltage, were investigated. In addition, the effects of applied voltage, supporting electrolyte, and initial concentration on indium (III) ion removal efficiency and specific energy consumption were investigated under the optimum balance of reasonable removal efficiency and relative low energy consumption. Experiment results indicate that a Fe/Al electrode pair is the most efficient choice of the four electrode pairs in terms of energy consumption. The optimum supporting electrolyte concentration, initial concentration, and applied voltage were found to be 100 mg/l NaCl, 20 mg/l, and 20 V, respectively. A higher pH at higher applied voltage (20 or 30 V) enhanced the precipitation of indium (III) ion as insoluble indium hydroxide, which improved the removal efficiency. Results from the indium (III) ion removal kinetics show that the kinetics data fit the pseudo second-order kinetic model well. Finally, the composition of the sludge produced was characterized with energy dispersion spectra (EDS).

  19. Kinetic and equilibrium study for the sorption of Pb(II) ions from ...

    African Journals Online (AJOL)

    Kinetic and equilibrium study for the sorption of Pb(II) ions from aqueous phase by water hyacinth ( Eichhornia crassipes ) ... Bulletin of the Chemical Society of Ethiopia ... Abstract. This paper reports the kinetic and equilibrium studies of Eichhornia crassipes root biomass as a biosorbent for Pb(II) ions from aqueous system.

  20. Energy Conservation Tests of a Coupled Kinetic-kinetic Plasma-neutral Transport Code

    Energy Technology Data Exchange (ETDEWEB)

    Stotler, D. P.; Chang, C. S.; Ku, S. H.; Lang, J.; Park, G.

    2012-08-29

    A Monte Carlo neutral transport routine, based on DEGAS2, has been coupled to the guiding center ion-electron-neutral neoclassical PIC code XGC0 to provide a realistic treatment of neutral atoms and molecules in the tokamak edge plasma. The DEGAS2 routine allows detailed atomic physics and plasma-material interaction processes to be incorporated into these simulations. The spatial pro le of the neutral particle source used in the DEGAS2 routine is determined from the uxes of XGC0 ions to the material surfaces. The kinetic-kinetic plasma-neutral transport capability is demonstrated with example pedestal fueling simulations.

  1. Energy dependence of the reaction rate constants of Ar+, Ar++ and N2+ ions with Cl2

    International Nuclear Information System (INIS)

    Lukac, P.; Holubcik, L.; Morva, I.; Lindinger, W.

    2002-01-01

    Dry etching processes using low temperature plasmas in Cl 2 and in Cl 2 -noble gas or nitrogen mixtures are common in the manufacture of semiconductor devices, but their chemical mechanisms are often poorly understood. Results are given for the reaction rate constant measurements of Ar + , Ar ++ , N 2 + ions with chlorine as a function of mean relative kinetic energy. The experiments were performed by using the innsbruck flow drift tube (IFDT) apparatus. Measurements were done at various E/N values, where E is the electric field strength and N the buffer gas density in the drift section. The mean relative kinetic energy KE CM between the ions and the neutral chlorine Cl 2 was calculated using the Wanniers formula. It was found that The N 2 + , Ar + and Ar ++ positive ions react with chlorine Cl 2 very fast and the corresponding reaction rate coefficients depend on the mean relative kinetic energy. For the reaction of Ar - with Cl 2 , its reaction coefficient depends also on the buffer gas. It can imply the enhancement of Cl 2 + ions during etching of Si in the Ar/Cl 2 mixtures. (nevyjel)

  2. Investigation of ion kinetic effects in direct-drive exploding-pusher implosions at the NIF

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, M. J., E-mail: mrosenbe@mit.edu; Zylstra, A. B.; Séguin, F. H.; Rinderknecht, H. G.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Waugh, C. J.; Sinenian, N.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); McKenty, P. W.; Hohenberger, M.; Radha, P. B.; Delettrez, J. A.; Glebov, V. Yu.; Betti, R.; Goncharov, V. N.; Knauer, J. P.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); and others

    2014-12-15

    Measurements of yield, ion temperature, areal density (ρR), shell convergence, and bang time have been obtained in shock-driven, D{sub 2} and D{sup 3}He gas-filled “exploding-pusher” inertial confinement fusion (ICF) implosions at the National Ignition Facility to assess the impact of ion kinetic effects. These measurements probed the shock convergence phase of ICF implosions, a critical stage in hot-spot ignition experiments. The data complement previous studies of kinetic effects in shock-driven implosions. Ion temperature and fuel ρR inferred from fusion-product spectroscopy are used to estimate the ion-ion mean free path in the gas. A trend of decreasing yields relative to the predictions of 2D DRACO hydrodynamics simulations with increasing Knudsen number (the ratio of ion-ion mean free path to minimum shell radius) suggests that ion kinetic effects are increasingly impacting the hot fuel region, in general agreement with previous results. The long mean free path conditions giving rise to ion kinetic effects in the gas are often prevalent during the shock phase of both exploding pushers and ablatively driven implosions, including ignition-relevant implosions.

  3. Radiation blistering of niobium in sequence irradiated by helium ions with different energy

    International Nuclear Information System (INIS)

    Das, S.K.; Kaminskij, M.S.; Guseva, M.I.; Gusev, V.M.; Krasulin, Yu.L.; Martynenko, Yu.V.; Rozina, I.A.

    1977-01-01

    The results of the investigation of the blistering of the surface of polycrystalline niobium foils subjected to successive irradiation by helium ions of energies of 3 to 50 keV are reported. The critical doses of irradiation, the types of blisters and the rate of erosion were determined. A comparative analysis of the formation of blisters on cold-rolled and annealed niobium has been made. On cold-rolled niobium the blistering is mainly due to ions with energies of 3 to 80 keV, on annealed niobium of 100 to 500 keV. The erosion of cold-rolled niobium takes place through blisters formed by the action of helium ions with energies of the order of 45 keV, and that of annealed niobium, through helium ions with energies of 100 to 500 keV. The observed differences in the formation of blisters on niobium irradiated with helium ions of a wide range of energies are explained by the change in the diffusion kinetics of implanted ions having a uniform distribution across the thickness of the target

  4. Fluorescence kinetics and positron annihilation kinetics investigations in cadmium sulfide crystals

    Energy Technology Data Exchange (ETDEWEB)

    Grillot, E; Bancie-Grillot, M; Egee, M [Reims Univ., 51 (France)

    1976-03-01

    Fluorescence kinetics and positrons annihilation kinetics investigations on CdS crystals, either very pure or with increasing contents of Ag-ions, led to similar and complementary results. Ag-ions mainly fill the cadmium vacancies of the lattice, building red emission luminogene centres, while green 'edge-emission' ones are destroyed. These latter, which involve an excited level active for high energy series fluorescence, seems actually related to cadmium vacancies.

  5. Split kinetic energy method for quantum systems with competing potentials

    International Nuclear Information System (INIS)

    Mineo, H.; Chao, Sheng D.

    2012-01-01

    For quantum systems with competing potentials, the conventional perturbation theory often yields an asymptotic series and the subsequent numerical outcome becomes uncertain. To tackle such a kind of problems, we develop a general solution scheme based on a new energy dissection idea. Instead of dividing the potential energy into “unperturbed” and “perturbed” terms, a partition of the kinetic energy is performed. By distributing the kinetic energy term in part into each individual potential, the Hamiltonian can be expressed as the sum of the subsystem Hamiltonians with respective competing potentials. The total wavefunction is expanded by using a linear combination of the basis sets of respective subsystem Hamiltonians. We first illustrate the solution procedure using a simple system consisting of a particle under the action of double δ-function potentials. Next, this method is applied to the prototype systems of a charged harmonic oscillator in strong magnetic field and the hydrogen molecule ion. Compared with the usual perturbation approach, this new scheme converges much faster to the exact solutions for both eigenvalues and eigenfunctions. When properly extended, this new solution scheme can be very useful for dealing with strongly coupling quantum systems. - Highlights: ► A new basis set expansion method is proposed. ► Split kinetic energy method is proposed to solve quantum eigenvalue problems. ► Significant improvement has been obtained in converging to exact results. ► Extension of such methods is promising and discussed.

  6. Heavy metal ion adsorption behavior in nitrogen-doped magnetic carbon nanoparticles: Isotherms and kinetic study

    International Nuclear Information System (INIS)

    Shin, Keun-Young; Hong, Jin-Yong; Jang, Jyongsik

    2011-01-01

    Graphical abstract: Display Omitted Research highlights: → The monodisperse and multigram-scale N-MCNPs are fabricated by carbonization of polypyrrole as a carbon precursor. → The synthesized N-MCNPs provide an enhanced adsorption uptake for various heavy metal ions. → The N-MCNPs can be applied to the Langmuir model and pseudo-second-order kinetics. → The iron-impregnated N-MCNPs are reused up to 5 times with no loss of removal efficiency. - Abstract: To clarify the heavy metal adsorption mechanism of nitrogen-doped magnetic carbon nanoparticles (N-MCNPs), adsorption capacity was investigated from the adsorption isotherms, kinetics and thermodynamics points of view. The obtained results showed that the equilibrium adsorption behavior of Cr 3+ ion onto the N-MCNPs can be applied to the Langmuir model and pseudo-second-order kinetics. It indicated that the fabricated N-MCNPs had the homogenous surface for adsorption and all adsorption sites had equal adsorption energies. Furthermore, the adsorption onto N-MCNPs taken place through a chemical process involving the valence forces. According to the thermodynamics, the adsorption process is spontaneous and endothermic in nature which means that the adsorption capacity increases with increasing temperature due to the enhanced mobility of adsorbate molecules. The effects of the solution pH and the species of heavy metal ion on the adsorption uptake were also studied. The synthesized N-MCNPs exhibited an enhanced adsorption capacity for the heavy metal ions due to the high surface area and large amount of nitrogen contents.

  7. Kinetics of ion/molecule reactions in Xe++acteone system

    International Nuclear Information System (INIS)

    Vinogradov, P.S.; Misharin, A.S.

    2002-01-01

    A reaction of Xe+ ion with acetone and subsequent transformations of the product ions at a buffer gas pressure (He) of 1.1 Torr were studied by the flow reactor technique mass spectrometry. A kinetic scheme describing the evolution of the ionic composition has been determined. The rate constants of the key reactions involved in the scheme have been evaluated. A channel of the production of acetone cation in A state in a charge transfer reaction was observed. A production of slowly reacting isomer of the acetone cation in secondary reactions was detected. Its product in the reaction with acetone is the 'nonprotonated dimer'. The kinetics of the production of ternary ions - ( CH 3 CO + CH 3 COCH 3 )(m/e=101), CH 3 COCH 3 H + (m/e=59) as well as the production of ions of the fourth generation ( CH 3 CO + (CH 3 COCH 3 ) 2 ) (m/e=159) and (CH 3 COCH 3 ) 2 H + was observed. CH 3 CO + ion (m/e=43) was found as the main reaction product. The main pathways scheme of ionic transformations is shown. (nevyjel)

  8. Channel for Applied Investigations on Low Energy Ion Beams of Cyclotron DC-60

    CERN Document Server

    Gikal, B N; Borisenko, A N; Fateev, A A; Gulbekyan, G G; Kalagin, I V; Kazacha, V I; Kazarinov, N Yu; Kolesov, I V; Lebedev, N I; Lysukhin, S N; Melnikov, V N

    2006-01-01

    The channel intended for carrying out applied investigations on the low energy ion beams having the kinetic energy 25 $Z/A$ keV/a.u. and transported from the ECR-source to a target is worked out. The channel structure and parameters of all its optics elements are defined. The calculation results of different ion types transportation are given. It is shown that ions having the ratio of their mass to charge Z/A=2-20 can be transported in the worked out channel with enough high expected efficiency. At that the ion beam diameter on the target is $\\sim$40 mm. The characteristics of the basic optical elements of the channel are also given.

  9. A method for measurements of neutral fragments kinetic energies released to a specific dissociation threshold: optical translational spectroscopy

    International Nuclear Information System (INIS)

    Roney, A.; Frigon, C.; Larzilliere, M.

    1999-01-01

    The optical translational spectroscopy technique, based on the principles of fast ion beam laser spectroscopy (FIBLAS) and translational spectroscopy, allows the kinetic energies study of neutral fragments released through free dissociation of a neutral molecule. This method presents interesting features such as near-threshold energy measurements and selection of a specific dissociation limit. The fragments resulting from free dissociation (not induced) of neutral molecules, produced by charge exchange processes with a fast ion beam, are probed by laser radiation. Monitoring of the laser-induced fluorescence allows high-resolution spectra due to the kinematic compression of the velocity spread. Measurements of kinetic energies released to the second limit of dissociation H(1s) + H(2l) of H 2 are put forth and compared with those obtained by means of off-axis translational spectroscopy

  10. An (e, 2e + ion) study of low-energy electron-impact ionization and fragmentation of tetrahydrofuran with high mass and energy resolutions

    Science.gov (United States)

    Ren, Xueguang; Pflüger, Thomas; Weyland, Marvin; Baek, Woon Yoon; Rabus, Hans; Ullrich, Joachim; Dorn, Alexander

    2014-10-01

    We study the low-energy (E0 = 26 eV) electron-impact induced ionization and fragmentation of tetrahydrofuran using a reaction microscope. All three final-state charged particles, i.e., two outgoing electrons and one fragment ion, are detected in triple coincidence such that the momentum vectors and, consequently, the kinetic energies for charged reaction products are determined. The ionic fragments are clearly identified in the experiment with a mass resolution of 1 amu. The fragmentation pathways of tetrahydrofuran are investigated by measuring the ion kinetic energy spectra and the binding energy spectra where an energy resolution of 1.5 eV has been achieved using the recently developed photoemission electron source. Here, we will discuss the fragmentation reactions for the cations C4H8O+, C4H7O+, C2H3O+, C3H_6^+, C3H_5^+, C3H_3^+, CH3O+, CHO+, and C2H_3^+.

  11. Kinetic Study of Zn2+ and Cd2+ Ions Sorption by Ceric Oxide Powder

    International Nuclear Information System (INIS)

    Hassan, H.S.; Abd El-Rahman, K.M.; El Sayed, A.A.

    2008-01-01

    Ceric Oxide powder was chemically synthesized and characterized using infrared spectra and x-ray diffraction. The sorptive removal of Zinc and Cadmium ions from aqueous waste solution using synthetic ceric oxide powder was investigated using batch technique. Experiments were carried out as a function of ph, particle size, solute concentration and temperature. The uptake of zinc was found to be greater than that of cadmium. A comparison of kinetic models applied to the sorption process of each ion was evaluated for the pseudo first order, the pseudo second order, and homogeneous particle diffusion kinetic models, respectively. The results showed that both the pseudo second order and the homogeneous particle diffusion model (HPDM) were found to best correlate the experimental rate data. The numerical values of the rate constants and particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy (Ε a ) and entropy (δ S * ) of activation for each sorption process were also calculated from the linearized form of Arrhenius equation

  12. Part 1: Kinetic energy dependencies of selected ion-molecule reactions; Part 2: Photochemistry of (FSO3)2, FSO3, and FNO

    International Nuclear Information System (INIS)

    Burley, J.D.

    1991-07-01

    In Part 1, guided ion beam mass spectroscopy is used to study the ion-molecule reactions O + ( 4 S) + H 2 (D 2 , HD), (O +4 S) + N 2 , C + ( 2 P) + O 2 and C + (P) + N 2 . Integral reaction cross sections are measured as a function of kinetic energy in the center-of-mass frame. Reaction mechanisms and dynamics are examined, and the results are compared to the predictions of phase space theory. In some cases, thermochemistry for neutral and ionic species is derived. In Part 2, photoabsorption cross sections are measured for peroxydisulfuryl difluoride, (FSO 3 ) 2 , and the fluorosulfate radical, FSO 3 . Photoabsorption cross sections of nitrosyl fluoride, FNO, are also measured, and the FNO absorption spectrum is analyzed and assigned. Spectral results for FNO are compared to the predictions and ab initio calculations and to those obtained for the isoelectronic compound HONO. 259 refs., 34 figs., 9 tabs

  13. Saturation mechanism of decaying ion temperature gradient driven turbulence with kinetic electrons

    International Nuclear Information System (INIS)

    Idomura, Yasuhiro

    2016-01-01

    We present full-f gyrokinetic simulations of the ion temperature gradient driven (ITG) turbulence including kinetic electrons. By comparing decaying ITG turbulence simulations with adiabatic and kinetic electron models, an impact of kinetic electrons on the ITG turbulence is investigated. It is found that significant electron transport occurs even in the ITG turbulence, and both ion and electron temperature profiles are relaxed. In steady states, both cases show upshifts of nonlinear critical ion temperature gradients from linear ones, while their saturation mechanisms are qualitatively different. In the adiabatic electron case, the ITG mode is stabilized by turbulence driven zonal flows. On the other hand, in the kinetic electron case, passing electrons transport shows fine resonant structures at mode rational surfaces, which generate corrugated density profiles. Such corrugated density profiles lead to fine radial electric fields following the neoclassical force balance relation. The resulting E × B shearing rate greatly exceeds the linear growth rate of the ITG mode. (author)

  14. Higher adsorption capacity of Spirulina platensis alga for Cr(VI) ions removal: parameter optimisation, equilibrium, kinetic and thermodynamic predictions.

    Science.gov (United States)

    Gunasundari, Elumalai; Senthil Kumar, Ponnusamy

    2017-04-01

    This study discusses about the biosorption of Cr(VI) ion from aqueous solution using ultrasonic assisted Spirulina platensis (UASP). The prepared UASP biosorbent was characterised by Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmet-Teller, scanning electron spectroscopy and energy dispersive X-ray and thermogravimetric analyses. The optimum condition for the maximum removal of Cr(VI) ions for an initial concentration of 50 mg/l by UASP was measured as: adsorbent dose of 1 g/l, pH of 3.0, contact time of 30 min and temperature of 303 K. Adsorption isotherm, kinetics and thermodynamic parameters were calculated. Freundlich model provided the best results for the removal of Cr(VI) ions by UASP. The adsorption kinetics of Cr(VI) ions onto UASP showed that the pseudo-first-order model was well in line with the experimental data. In the thermodynamic study, the parameters like Gibb's free energy, enthalpy and entropy changes were evaluated. This result explains that the adsorption of Cr(VI) ions onto the UASP was exothermic and spontaneous in nature. Desorption of the biosorbent was done using different desorbing agents in which NaOH gave the best result. The prepared material showed higher affinity for the removal of Cr(VI) ions and this may be an alternative material to the existing commercial adsorbents.

  15. Kinetic study of Cs+ and Eu3+ ions sorption by zirconium oxide powder

    International Nuclear Information System (INIS)

    Hanafi, H.A.; Hassan, H.S.; Hamed, M.M.

    2009-01-01

    Full text: Zirconium oxide powder was chemically synthesized by sol-gel method and characterized using infrared spectra and x-ray diffraction. The sorptive removal of cesium and europium ions from aqueous waste solution using synthetic zirconium oxide powder was investigated using batch technique. Experiments were carried out as a function of pH, time and temperature. The uptake of europium was found to be greater than that of cesium. A comparison of kinetic models applied to the sorption process of each ion was evaluated for the pseudo first order, the pseudo second order, and homogeneous particle diffusion kinetic models, respectively. The results showed that both the pseudo second order and the homogeneous particle diffusion models (HPDM) were found to best correlate the experimental rate data. The numerical values of the rate constants and particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy (Ea) and entropy (Δ S*) of activation for each sorption process were also calculated from the linearized form of Arrhenius equation. (author)

  16. Demonstration of Ion Kinetic Effects in Inertial Confinement Fusion Implosions and Investigation of Magnetic Reconnection Using Laser-Produced Plasmas

    Science.gov (United States)

    Rosenberg, M. J.

    2016-10-01

    Shock-driven laser inertial confinement fusion (ICF) implosions have demonstrated the presence of ion kinetic effects in ICF implosions and also have been used as a proton source to probe the strongly driven reconnection of MG magnetic fields in laser-generated plasmas. Ion kinetic effects arise during the shock-convergence phase of ICF implosions when the mean free path for ion-ion collisions (λii) approaches the size of the hot-fuel region (Rfuel) and may impact hot-spot formation and the possibility of ignition. To isolate and study ion kinetic effects, the ratio of N - K =λii /Rfuel was varied in D3He-filled, shock-driven implosions at the Omega Laser Facility and the National Ignition Facility, from hydrodynamic-like conditions (NK 0.01) to strongly kinetic conditions (NK 10). A strong trend of decreasing fusion yields relative to the predictions of hydrodynamic models is observed as NK increases from 0.1 to 10. Hydrodynamics simulations that include basic models of the kinetic effects that are likely to be present in these experiments-namely, ion diffusion and Knudsen-layer reduction of the fusion reactivity-are better able to capture the experimental results. This type of implosion has also been used as a source of monoenergetic 15-MeV protons to image magnetic fields driven to reconnect in laser-produced plasmas at conditions similar to those encountered at the Earth's magnetopause. These experiments demonstrate that for both symmetric and asymmetric magnetic-reconnection configurations, when plasma flows are much stronger than the nominal Alfvén speed, the rate of magnetic-flux annihilation is determined by the flow velocity and is largely insensitive to initial plasma conditions. This work was supported by the Department of Energy Grant Number DENA0001857.

  17. Scanning ion microscopy with low energy lithium ions

    International Nuclear Information System (INIS)

    Twedt, Kevin A.; Chen, Lei; McClelland, Jabez J.

    2014-01-01

    Using an ion source based on photoionization of laser-cooled lithium atoms, we have developed a scanning ion microscope with probe sizes of a few tens of nanometers and beam energies from 500 eV to 5 keV. These beam energies are much lower than the typical operating energies of the helium ion microscope or gallium focused ion beam systems. We demonstrate how low energy can be advantageous in ion microscopy when detecting backscattered ions, due to a decreased interaction volume and the potential for surface sensitive composition analysis. As an example application that demonstrates these advantages, we non-destructively image the removal of a thin residual resist layer during plasma etching in a nano-imprint lithography process. - Highlights: • We use an ion source based on photoionization of laser-cooled lithium atoms. • The ion source makes possible a low energy (500 eV to 5 keV) scanning ion microscope. • Low energy is preferred for ion microscopy with backscattered ions. • We use the microscope to image a thin resist used in nano-imprint lithography

  18. Monte Carlo simulation of heavy ion induced kinetic electron emission from an Al surface

    CERN Document Server

    Ohya, K

    2002-01-01

    A Monte Carlo simulation is performed in order to study heavy ion induced kinetic electron emission from an Al surface. In the simulation, excitation of conduction band electrons by the projectile ion and recoiling target atoms is treated on the basis of the partial wave expansion method, and the cascade multiplication process of the excited electrons is simulated as well as collision cascade of the recoiling target atoms. Experimental electron yields near conventional threshold energies of heavy ions are simulated by an assumption of a lowering in the apparent surface barrier for the electrons. The present calculation derives components for electron excitations by the projectile ion, the recoiling target atoms and the electron cascades, from the calculated total electron yield. The component from the recoiling target atoms increases with increasing projectile mass, whereas the component from the electron cascade decreases. Although the components from the projectile ion and the electron cascade increase with...

  19. Reaction dynamics of the four-centered elimination CH2OH + --> CHO + +H2: Measurement of kinetic energy release distribution and classical trajectory calculation

    Science.gov (United States)

    Lee, Tae Geol; Park, Seung C.; Kim, Myung Soo

    1996-03-01

    Mass-analyzed ion kinetic energy (MIKE) spectrum of CHO+ generated in the unimolecular dissociation of CH2OH+ was measured. Kinetic energy release distribution (KERD) was evaluated by analyzing the spectrum according to the algorithm developed previously. The average kinetic energy release evaluated from the distribution was extraordinarily large, 1.63 eV, corresponding to 75% of the reverse barrier of the reaction. A global analytical potential energy surface was constructed such that the experimental energetics was represented and that various features in the ab initio potential energy surface were closely reproduced. Classical trajectory calculation was carried out with the global analytical potential energy surface to investigate the causes for the extraordinarily large kinetic energy release. Based on the detailed dynamical calculations, it was found that the strained bending forces at the transition state and strengthening of the CO bond from double to triple bond character were mainly responsible for such a significant kinetic energy release. In addition, the dissociation products H2 and CHO+ ion were found to be rotationally excited in the trajectory calculations. This was attributed to the asymmetry of the transition state and the release of asymmetric bending forces. Also, the bending vibrational modes of CHO+ and the H2 stretching mode, which are coupled with the bending coordinates, were found to be moderately excited.

  20. Effect of Landau damping on kinetic Alfven and ion-acoustic solitary waves in a magnetized nonthermal plasma with warm ions

    International Nuclear Information System (INIS)

    Bandyopadhyay, Anup; Das, K.P.

    2002-01-01

    The evolution equations describing both kinetic Alfven wave and ion-acoustic wave in a nonthermal magnetized plasma with warm ions including weak nonlinearity and weak dispersion with the effect of Landau damping have been derived. These equations reduce to two coupled equations constituting the KdV-ZK (Korteweg-de Vries-Zakharov-Kuznetsov) equation for both kinetic Alfven wave and ion-acoustic wave, including an extra term accounting for the effect of Landau damping. When the coefficient of the nonlinear term of the evolution equation for ion-acoustic wave vanishes, the nonlinear behavior of ion-acoustic wave, including the effect of Landau damping, is described by two coupled equations constituting the modified KdV-ZK (MKdV-ZK) equation, including an extra term accounting for the effect of Landau damping. It is found that there is no effect of Landau damping on the solitary structures of the kinetic Alfven wave. Both the macroscopic evolution equations for the ion-acoustic wave admits solitary wave solutions, the former having a sech 2 profile and the latter having a sech profile. In either case, it is found that the amplitude of the ion-acoustic solitary wave decreases slowly with time

  1. Plasma heating by kinetic Alfven wave

    International Nuclear Information System (INIS)

    Assis, A.S. de.

    1982-01-01

    The heating of a nonuniform plasma (electron-ion) due to the resonant excitation of the shear Alfven wave in the low β regime is studied using initially the ideal MHD model and posteriorly using the kinetic model. The Vlasov equation for ions and the drift kinetic equation for electrons have been used. Through the ideal MHD model, it is concluded that the energy absorption is due to the continuous spectrum (phase mixing) which the shear Alfven wave has in a nonuniform plasma. An explicit expression for the energy absorption is derived. Through the kinetic model it is concluded that the energy absorption is due to a resonant mode convertion of the incident wave into the kinetic Alfven wave which propagates away from the resonant region. Its electron Landau damping has been observed. There has been a concordance with the MHD calculations. (Author) [pt

  2. Kinetic energy of shakeoff atomic electrons from 37K β+ decay

    Science.gov (United States)

    Behr, J. A.; Gorelov, A.; Farfan, C.; Smale, S.; Olchanski, K.; Kurchananov, L.; Anholm, M.; Behling, R. S.; Fenker, B.; Shidling, P. D.; Mehlman, M.; Melconian, D.; Ashery, D.; Gwinner, G.; Trinat Collaboration

    2013-10-01

    We have measured the kinetic energies from 0 to 30 eV of atomic shakeoff electrons from the β+ decay of 37K. Despite much experimental and theoretical work on the distribution of final ion charge states, shakeoff electrons from β- decay have only been measured with energies above 150 eV [Mitrokhovich, Nucl. Phys. Atom. Energy, 11, 125 (2010)]. We use our magneto-optical trap's time-varying magnetic quadrupole field combined with a uniform electric field as a spectrometer. Our result has more 15 eV electrons than a model using the sudden approximation and hydrogenic wavefunctions [Levinger, Phys. Rev. 90, 11 (1958)]. The total energy carried away by electrons is, as expected, a negligible correction to superallowed Ft values. Understanding the energy of these low-energy electrons is important for their use in precision β decay to select events coming from trapped atoms and start time-of-flight for the recoil ions. Our results could provide a benchmark for shakeoff electron calculations used for biological radiation damage [Lee, Comp. Math. Meth in Medicine doi:10.1155/2012/651475]. Support: NSERC, NRC through TRIUMF, DOE ER41747 ER40773, State of Texas, Israel Science Foundation.

  3. Study of kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 6

    International Nuclear Information System (INIS)

    Plicka, J.; Stamberg, K.; Cabicar, J.; Gosman, A.

    1986-01-01

    The description of kinetics of ion exchange in ternary system was based upon three Nernst-Planck equations, each of them describing the particle diffusion flux of a given counterion as an independent process. For experimental verification, the strongly acidic cation exchanger OSTION KS 08 the shallow-bed technique, and 0.2 mol x dm -3 aqueous nitrate solutions were chosen. The kinetics of ion exchange in the system of cations Na + - Mg 2+ - UO 2 2+ was studied. The values of diffusion coefficients obtained by evaluating of kinetics of isotope exchange and binary ion exchange were used for calculation. The comparison of calculated exchange rate curves with the experimental ones was made. It was found that the exchanging counterions were affected by each other. (author)

  4. On the defect structure due to low energy ion bombardment of graphite

    Science.gov (United States)

    Marton, D.; Bu, H.; Boyd, K. J.; Todorov, S. S.; Al-Bayati, A. H.; Rabalais, J. W.

    1995-03-01

    Graphite surfaces cleaved perpendicular to the c axis have been irradiated with low doses of Ar + ions at 50 eV kinetic energy and perpendicular incidence. Scanning tunneling micrographs (STM) of these irradiated surfaces exhibited dome-like features as well as point defects. These dome-like features retain undisturbed graphite periodicity. This finding is attributed to the stopping of ions between the first and second graphite sheets. The possibility of doping semiconductors at extremely shallow depths is raised.

  5. Deviation from an inverse cosine dependence of kinetic secondary electron emission for angle of incidence at keV energy

    International Nuclear Information System (INIS)

    Ohya, Kaoru; Kawata, Jun; Mori, Ichiro

    1989-01-01

    Incident angle dependence of kinetic secondary electron emission from metals resulting from incidence of keV ions is investigated by computer simulation with the TRIM Monte Carlo program of ion scattering in matter. The results show large deviations from the inverse cosine dependence, which derives from high-energy approximation, because of a series of elastic collisions of incident ions with metal atoms. In the keV energy region, the elastic collisions have two different effects on the angular dependence for relatively high-energy light ions and for low-energy heavy ions: they result in over- and under-inverse-cosine dependences, respectively. The properties are observed even with an experiment of the keV-neutral incidence on a contaminated surface. In addition, the effects of the thin oxide layer and roughness on the surface are examined with simplified models. (author)

  6. Characterization of a cold cathode Penning ion source for the implantation of noble gases beneath 2D monolayers on metals: Ions and neutrals

    Energy Technology Data Exchange (ETDEWEB)

    Cun, Huanyao, E-mail: hycun1@physik.uzh.ch, E-mail: greber@physik.uzh.ch; Spescha, Annina; Schuler, Adrian; Hengsberger, Matthias; Osterwalder, Jürg; Greber, Thomas, E-mail: hycun1@physik.uzh.ch, E-mail: greber@physik.uzh.ch [Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich (Switzerland)

    2016-03-15

    Argon ion kinetic energy spectra at different discharge voltages (between 480 and 600 V) of a commercial cold cathode ion source IQP10/63 are reported. The high kinetic energy cut-off depends on the discharge voltage and the corresponding plasma potential due to excess positive charges which is found to be about 136 V. Exposure of single layer hexagonal boron nitride on rhodium to the beam of the ion source leads to the formation of nanotents, i.e., stable atomic protrusions. A positive bias voltage is applied to the target sample to block the positive ions produced by the ion source. However, application of a positive bias potential (800 eV), which is higher than the kinetic energy cut-off, still allows the formation of nanotents and its observation with scanning tunneling microscopy. This indicates that the ion source also produces neutral atoms with kinetic energies higher than the penetration threshold across a single layer of hexagonal boron nitride.

  7. Kinetic plasma simulation of ion beam extraction from an ECR ion source

    International Nuclear Information System (INIS)

    Elliott, S.M.; White, E.K.; Simkin, J.

    2012-01-01

    Designing optimized ECR (electron cyclotron resonance) ion beam sources can be streamlined by the accurate simulation of beam optical properties in order to predict ion extraction behavior. The complexity of these models, however, can make PIC-based simulations time-consuming. In this paper, we first describe a simple kinetic plasma finite element simulation of extraction of a proton beam from a permanent magnet hexapole ECR ion source. Second, we analyze the influence of secondary electrons generated by ion collisions in the residual gas on the space charge of a proton beam of a dual-solenoid ECR ion source. The finite element method (FEM) offers a fast modeling environment, allowing analysis of ion beam behavior under conditions of varying current density, electrode potential, and gas pressure. The new version of SCALA/TOSCA v14 permits the making of simulations in tens of minutes to a few hours on standard computer platforms without the need of particle-in-cell methods. The paper is followed by the slides of the presentation. (authors)

  8. Nonlocal kinetic-energy-density functionals

    International Nuclear Information System (INIS)

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.

    1996-01-01

    In this paper we present nonlocal kinetic-energy functionals T[n] within the average density approximation (ADA) framework, which do not require any extra input when applied to any electron system and recover the exact kinetic energy and the linear response function of a homogeneous system. In contrast with previous ADA functionals, these present good behavior of the long-range tail of the exact weight function. The averaging procedure for the kinetic functional (averaging the Fermi momentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculation of extended systems, and it gives excellent results when applied to atoms and jellium surfaces. copyright 1996 The American Physical Society

  9. Ion - biomolecule interactions and radiation damage

    International Nuclear Information System (INIS)

    Schlathoelter, T.

    2004-01-01

    Full text: The biological effects of ionizing radiation in living cells are not a mere result of the direct impact of high energy quanta of radiation. Secondary particles such as low energy electrons, radicals and (multiply charged) ions are formed within the track. The interaction of these secondary particles with biologically relevant molecules is responsible for a large fraction of biological radiation damage to a cell, as well. Singly and multiply charged ions can be of importance as both, primary and secondary particles, and are known to cause severe biological damage. For instance, in heavy ion therapy and proton therapy the pronounced Bragg peak of fast (typically a few 100 MeV/u) ions in biological tissue is utilized. The Bragg peak is located at a depth, where the ions (mostly C q+ or protons) are slowed down to about 100 keV/u and have their maximum linear energy transfer (LET) to the medium. This depth is reasonably well defined and depends on the initial ion kinetic energy. Since the ions are rapidly stopped in this energy range, penetration beyond the Bragg peak is weak and it is thus possible to 'scan' the Bragg peak through a malignant tumour without excessive damage of the surrounding tissue by mere variation of the ion kinetic energy (i.e. the penetration depth). Severe biological damage is almost only possible, when the track of a primary quantum of ionizing radiation crosses the nucleus of a cell. Particularly the induction of double strand breaks of DNA or clustered DNA lesions is potentially lethal or mutagenic. A primary particle interacting with individual molecules within this environment leads to molecular excitation, ionization and fragmentation. In the process, the primary particle looses energy and slow secondary electrons and ions are formed, which might induce further damage. For a deep understanding of biological radiation damage on the level of individual molecules it is thus important to quantify excitation, ionization and

  10. Kinetics of adsorption of zinc-ions by doped manganese dioxides

    International Nuclear Information System (INIS)

    Rophael, M.W.; Mourad, W.E.; Khalil, L.B.; Malati, M.A.

    1979-01-01

    Using 65 Zn-labelled solutions, the kinetics of the specific adsorption of Zn 2+ -ions by doped manganese dioxides was studied, at pH values corresponding to their isoelectric points (IEP's), by γ-ray scintillation counting. The rate of the fast adsorption of Zn 2+ -ions by doped dioxides increased in the series: Li + -doped 2+ -ions in about 10 minutes exhibited a similar increase. Compared to the undoped sample, the extent and the rate of adsorption were lower for the samples doped with an ion of valence 4. (author)

  11. Kinetic study of heavy metal ions removal by ion exchange in batch conical air spouted bed

    Directory of Open Access Journals (Sweden)

    T.M. Zewail

    2015-03-01

    Full Text Available Spouted bed contactor is a hybrid of fixed and fluidized bed contactors, which retains the advantages of each with good hydrodynamic conditions. The aim of the present study is to investigate the performance of a batch conical air spouted vessel for heavy metal removal by strong cation exchange resins (AMBERJET 1200 Na. The effect of various parameters such as type of heavy metal ions (Ni+2 and Pb+2, contact time, superficial air velocity and initial heavy metal ion concentration on % heavy metal ion removal has been investigated. It has been found that under optimum conditions 98% and 99% removal of Ni+2 and Pb+2 were achieved respectively. Several kinetic models were used to test the experimental data and to examine the controlling mechanism of the sorption process. The present results of Ni+2 and Pb+2 well fit pseudo second order kinetic model with a high correlation coefficient. Both film diffusion and intra-particle diffusion contribute to the ion exchange process. The present study revealed that spouted bed vessel may provide an effective alternative for conducting ion exchange reactions.

  12. A unified theory of resonant excitation of kinetic ballooning modes by energetic ions/alpha particles in tokamaks

    International Nuclear Information System (INIS)

    Biglari, H.; Chen, L.

    1991-10-01

    A complete theory of wave-particle interactions is presented whereby both circulating and trapped energetic ions can destabilize kinetic ballooning modes in tokamaks. Four qualitatively different types of resonances, involving wave-precessional drift, wave-transit, wave-bounce, and precessional drift-bounce interactions, are identified, and the destabilization potential of each is assessed. For a characteristic slowing-down distribution function, the dominant interaction is that which taps those resonant ions with the highest energy. Implications of the theory for present and future generation fusion experiments are discussed. 16 refs

  13. Three-dimensional stability of solitary kinetic Alfven waves and ion-acoustic waves

    International Nuclear Information System (INIS)

    Ghosh, G.; Das, K.P.

    1994-01-01

    Starting from a set of equations that lead to a linear dispersion relation coupling kinetic Alfven waves and ion-acoustic waves, three-dimensional KdV equations are derived for these waves. These equations are then used to investigate the three-dimensional stability of solitary kinetic Alfven waves and ion-acoustic waves by the small-k perturbation expansion method of Rowlands and Infeld. For kinetic Alfven waves it is found that there is instability if the direction of the plane-wave perturbation lies inside a cone, and the growth rate of the instability attains a maximum when the direction of the perturbation lies in the plane containing the external magnetic field and the direction of propagation of the solitary wave. For ion-acoustic waves the growth rate of instability attains a maximum when the direction of the perturbation lies in a plane perpendicular to the direction of propagation of the solitary wave. (Author)

  14. Live cell imaging combined with high-energy single-ion microbeam

    Science.gov (United States)

    Guo, Na; Du, Guanghua; Liu, Wenjing; Guo, Jinlong; Wu, Ruqun; Chen, Hao; Wei, Junzhe

    2016-03-01

    DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10-3 s-1 and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10-2 s-1.

  15. First measurements of the ion energy distribution at the divertor strike point during DIII-D disruptions

    International Nuclear Information System (INIS)

    Parks, P.B.; Brooks, N.H.; West, W.P.; Wong, C.P.C.; Bastasz, R.; Wampler, W.R.; Whyte, D.

    1995-12-01

    Plasma/wall interaction studies are being carried out using the Divertor Materials Exposure System (DiMES) on DIII-D. The objective of the experiment is to determine the kinetic energy and flux of deuterium ions reaching the divertor target during argon-induced radiative disruptions. The experiment utilizes a special slotted ion analyzer mounted over a Si sample to collect the fast charge-exchange (CX) deuterium neutrals emitted within the recycled cold neutral layer (CNL) which serves as a CX target for the incident ions. A theoretical interpretation of the experiment reveals a strong forward pitch-angle dependence in the approaching ion distribution function. The depth distribution of the trapped D in the Si sample was measured using low-energy direct recoil spectroscopy. Comparison with the TRIM code using monoenergetic ions indicated that the best fit to the data was obtained for an ion energy of 100 eV

  16. An improved experimental scheme for simultaneous measurement of high-resolution zero electron kinetic energy (ZEKE) photoelectron and threshold photoion (MATI) spectra

    Science.gov (United States)

    Michels, François; Mazzoni, Federico; Becucci, Maurizio; Müller-Dethlefs, Klaus

    2017-10-01

    An improved detection scheme is presented for threshold ionization spectroscopy with simultaneous recording of the Zero Electron Kinetic Energy (ZEKE) and Mass Analysed Threshold Ionisation (MATI) signals. The objective is to obtain accurate dissociation energies for larger molecular clusters by simultaneously detecting the fragment and parent ion MATI signals with identical transmission. The scheme preserves an optimal ZEKE spectral resolution together with excellent separation of the spontaneous ion and MATI signals in the time-of-flight mass spectrum. The resulting improvement in sensitivity will allow for the determination of dissociation energies in clusters with substantial mass difference between parent and daughter ions.

  17. Assessment of ion kinetic effects in shock-driven inertial confinement fusion implosions using fusion burn imaging

    International Nuclear Information System (INIS)

    Rosenberg, M. J.; Séguin, F. H.; Rinderknecht, H. G.; Zylstra, A. B.; Li, C. K.; Sio, H.; Johnson, M. Gatu; Frenje, J. A.; Petrasso, R. D.; Amendt, P. A.; Wilks, S. C.; Pino, J.; Atzeni, S.; Hoffman, N. M.; Kagan, G.; Molvig, K.; Glebov, V. Yu.; Stoeckl, C.; Seka, W.; Marshall, F. J.

    2015-01-01

    The significance and nature of ion kinetic effects in D 3 He-filled, shock-driven inertial confinement fusion implosions are assessed through measurements of fusion burn profiles. Over this series of experiments, the ratio of ion-ion mean free path to minimum shell radius (the Knudsen number, N K ) was varied from 0.3 to 9 in order to probe hydrodynamic-like to strongly kinetic plasma conditions; as the Knudsen number increased, hydrodynamic models increasingly failed to match measured yields, while an empirically-tuned, first-step model of ion kinetic effects better captured the observed yield trends [Rosenberg et al., Phys. Rev. Lett. 112, 185001 (2014)]. Here, spatially resolved measurements of the fusion burn are used to examine kinetic ion transport effects in greater detail, adding an additional dimension of understanding that goes beyond zero-dimensional integrated quantities to one-dimensional profiles. In agreement with the previous findings, a comparison of measured and simulated burn profiles shows that models including ion transport effects are able to better match the experimental results. In implosions characterized by large Knudsen numbers (N K  ∼ 3), the fusion burn profiles predicted by hydrodynamics simulations that exclude ion mean free path effects are peaked far from the origin, in stark disagreement with the experimentally observed profiles, which are centrally peaked. In contrast, a hydrodynamics simulation that includes a model of ion diffusion is able to qualitatively match the measured profile shapes. Therefore, ion diffusion or diffusion-like processes are identified as a plausible explanation of the observed trends, though further refinement of the models is needed for a more complete and quantitative understanding of ion kinetic effects

  18. Assessment of ion kinetic effects in shock-driven inertial confinement fusion implosions using fusion burn imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, M. J., E-mail: mros@lle.rochester.edu; Séguin, F. H.; Rinderknecht, H. G.; Zylstra, A. B.; Li, C. K.; Sio, H.; Johnson, M. Gatu; Frenje, J. A.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Amendt, P. A.; Wilks, S. C.; Pino, J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Atzeni, S. [Dipartimento SBAI, Università di Roma “La Sapienza” and CNISM, Via A. Scarpa 14-16, I-00161 Roma (Italy); Hoffman, N. M.; Kagan, G.; Molvig, K. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Glebov, V. Yu.; Stoeckl, C.; Seka, W.; Marshall, F. J. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); and others

    2015-06-15

    The significance and nature of ion kinetic effects in D{sup 3}He-filled, shock-driven inertial confinement fusion implosions are assessed through measurements of fusion burn profiles. Over this series of experiments, the ratio of ion-ion mean free path to minimum shell radius (the Knudsen number, N{sub K}) was varied from 0.3 to 9 in order to probe hydrodynamic-like to strongly kinetic plasma conditions; as the Knudsen number increased, hydrodynamic models increasingly failed to match measured yields, while an empirically-tuned, first-step model of ion kinetic effects better captured the observed yield trends [Rosenberg et al., Phys. Rev. Lett. 112, 185001 (2014)]. Here, spatially resolved measurements of the fusion burn are used to examine kinetic ion transport effects in greater detail, adding an additional dimension of understanding that goes beyond zero-dimensional integrated quantities to one-dimensional profiles. In agreement with the previous findings, a comparison of measured and simulated burn profiles shows that models including ion transport effects are able to better match the experimental results. In implosions characterized by large Knudsen numbers (N{sub K} ∼ 3), the fusion burn profiles predicted by hydrodynamics simulations that exclude ion mean free path effects are peaked far from the origin, in stark disagreement with the experimentally observed profiles, which are centrally peaked. In contrast, a hydrodynamics simulation that includes a model of ion diffusion is able to qualitatively match the measured profile shapes. Therefore, ion diffusion or diffusion-like processes are identified as a plausible explanation of the observed trends, though further refinement of the models is needed for a more complete and quantitative understanding of ion kinetic effects.

  19. Energy conversion through mass loading of escaping ionospheric ions for different Kp values

    Science.gov (United States)

    Yamauchi, Masatoshi; Slapak, Rikard

    2018-01-01

    By conserving momentum during the mixing of fast solar wind flow and slow planetary ion flow in an inelastic way, mass loading converts kinetic energy to other forms - e.g. first to electrical energy through charge separation and then to thermal energy (randomness) through gyromotion of the newly born cold ions for the comet and Mars cases. Here, we consider the Earth's exterior cusp and plasma mantle, where the ionospheric origin escaping ions with finite temperatures are loaded into the decelerated solar wind flow. Due to direct connectivity to the ionosphere through the geomagnetic field, a large part of this electrical energy is consumed to maintain field-aligned currents (FACs) toward the ionosphere, in a similar manner as the solar wind-driven ionospheric convection in the open geomagnetic field region. We show that the energy extraction rate by the mass loading of escaping ions (ΔK) is sufficient to explain the cusp FACs, and that ΔK depends only on the solar wind velocity accessing the mass-loading region (usw) and the total mass flux of the escaping ions into this region (mloadFload), as ΔK ˜ -mloadFloadu2sw/4. The expected distribution of the separated charges by this process also predicts the observed flowing directions of the cusp FACs for different interplanetary magnetic field (IMF) orientations if we include the deflection of the solar wind flow directions in the exterior cusp. Using empirical relations of u0 ∝ Kp + 1.2 and Fload ∝ exp(0.45Kp) for Kp = 1-7, where u0 is the solar wind velocity upstream of the bow shock, ΔK becomes a simple function of Kp as log10(ΔK) = 0.2 ṡ Kp + 2 ṡ log10(Kp + 1.2) + constant. The major contribution of this nearly linear increase is the Fload term, i.e. positive feedback between the increase of ion escaping rate Fload through the increased energy consumption in the ionosphere for high Kp, and subsequent extraction of more kinetic energy ΔK from the solar wind to the current system by the increased

  20. Nonlinear saturation of the slab ITG instability and zonal flow generation with fully kinetic ions

    Science.gov (United States)

    Miecnikowski, Matthew T.; Sturdevant, Benjamin J.; Chen, Yang; Parker, Scott E.

    2018-05-01

    Fully kinetic turbulence models are of interest for their potential to validate or replace gyrokinetic models in plasma regimes where the gyrokinetic expansion parameters are marginal. Here, we demonstrate fully kinetic ion capability by simulating the growth and nonlinear saturation of the ion-temperature-gradient instability in shearless slab geometry assuming adiabatic electrons and including zonal flow dynamics. The ion trajectories are integrated using the Lorentz force, and the cyclotron motion is fully resolved. Linear growth and nonlinear saturation characteristics show excellent agreement with analogous gyrokinetic simulations across a wide range of parameters. The fully kinetic simulation accurately reproduces the nonlinearly generated zonal flow. This work demonstrates nonlinear capability, resolution of weak gradient drive, and zonal flow physics, which are critical aspects of modeling plasma turbulence with full ion dynamics.

  1. Temperature and energy effects on secondary electron emission from SiC ceramics induced by Xe17+ ions.

    Science.gov (United States)

    Zeng, Lixia; Zhou, Xianming; Cheng, Rui; Wang, Xing; Ren, Jieru; Lei, Yu; Ma, Lidong; Zhao, Yongtao; Zhang, Xiaoan; Xu, Zhongfeng

    2017-07-25

    Secondary electron emission yield from the surface of SiC ceramics induced by Xe 17+ ions has been measured as a function of target temperature and incident energy. In the temperature range of 463-659 K, the total yield gradually decreases with increasing target temperature. The decrease is about 57% for 3.2 MeV Xe 17+ impact, and about 62% for 4.0 MeV Xe 17+ impact, which is much larger than the decrease observed previously for ion impact at low charged states. The yield dependence on the temperature is discussed in terms of work function, because both kinetic electron emission and potential electron emission are influenced by work function. In addition, our experimental data show that the total electron yield gradually increases with the kinetic energy of projectile, when the target is at a constant temperature higher than room temperature. This result can be explained by electronic stopping power which plays an important role in kinetic electron emission.

  2. Ion-neutral gas reactions in a collision/reaction cell in inductively coupled plasma mass spectrometry: Correlation of ion signal decrease to kinetic rate constants

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Patrick J. [Trace Element Research Laboratory, School of Earth Sciences, The Ohio State University, 125 S. Oval Mall, Columbus, OH 43210 (United States); Department of Chemistry, The Ohio State University, 120 18th Avenue, Columbus, OH 43210 (United States); Olesik, John W., E-mail: olesik.2@osu.edu [Trace Element Research Laboratory, School of Earth Sciences, The Ohio State University, 125 S. Oval Mall, Columbus, OH 43210 (United States)

    2015-03-01

    Reaction gas flow rate dependent Ar{sub 2}{sup +} and Ar{sup +} signals are correlated to fundamental kinetic rate coefficients. A simple calculation, assuming that gas exits the reaction cell due only to effusion, is described to estimate the gas pressure in the reaction cell. The value of the product of the kinetic rate constant and the ion residence time in the reaction cell can be determined from experimental measurement of the decrease in an ion signal as a function of reaction gas flow rate. New kinetic rate constants are determined for the reaction of CH{sub 3}F with Ar{sup +} and Ar{sub 2}{sup +}. - Highlights: • How to determine pressure and the product of the kinetic rate constant times the ion residence time in reaction cell • Relate measured ICP-DRC-MS signals versus gas flow rate to kinetic rate constants measured previously using SIFT-MS • Describe how to determine previously unmeasured kinetic rate constants using ICP-DRC-MS.

  3. Kinetics and exchange mechanism of Zn2+and Eu3+ ions on tin and zirconium silicates as a cation exchange materials

    International Nuclear Information System (INIS)

    Zakaria, E.S.; Ali, I.M.; Aly, H.F.

    2005-01-01

    Tin and zirconium silicates have been prepared with Sn/Si and Zr/Si molar ratios of 1 and 0.75, respectively. Kinetics and exchange studies of Zn 2+ and Eu 3+ ions on the prepared stannous and zirconium silicates have been carried out as a function of reaction temperature, particle diameters, solution concentration of the exchanging cations from water and alcohol-water mixture. The capacity of the exchangers for the studied cations from alcohol-water mixture was found higher than in pure aqueous solutions. The rate of exchange was dependent on particle diameters and independent on concentration of metal ions. The kinetic and thermodynamic parameters, vis. effective diffusion coefficients, activation energies and entropies of activation have been evaluated. Negative values of entropy, enthalpy and free energy of activation for Zn 2+ /M + and Eu 3+ /H + on both exchangers have been recorded at different conditions

  4. Kinetic k-essence ghost dark energy model

    International Nuclear Information System (INIS)

    Rozas-Fernández, Alberto

    2012-01-01

    A ghost dark energy model has been recently put forward to explain the current accelerated expansion of the Universe. In this model, the energy density of ghost dark energy, which comes from the Veneziano ghost of QCD, is proportional to the Hubble parameter, ρ D =αH. Here α is a constant of order Λ QCD 3 where Λ QCD ∼100 MeV is the QCD mass scale. We consider a connection between ghost dark energy with/without interaction between the components of the dark sector and the kinetic k-essence field. It is shown that the cosmological evolution of the ghost dark energy dominated Universe can be completely described a kinetic k-essence scalar field. We reconstruct the kinetic k-essence function F(X) in a flat Friedmann-Robertson-Walker Universe according to the evolution of ghost dark energy density.

  5. Atomic mixing of metallic bilayers Ni/Ti irradiated with high energy heavy ions; Etude du melange ionique de bicouches metalliques Ni/Ti irradiees avec des ions lourds de haute energie

    Energy Technology Data Exchange (ETDEWEB)

    Leguay, R

    1994-09-26

    We have studied the ionic mixing of Nl(105 angstrom) bilayers irradiated, at 80 and 300 K. with GeV heavy ions. In this energy range, the energy transfer from the incident ions to the target occurs mainly through electronic excitations. We have shown that this energy transfer induces a strong ionic mixing at the Nl/Ti interface. The thickness of the mixed interlayer increases with the fluence. At low fluences (10{sup 12} ions/cm{sup 2}), the Nl/Ti interface is rough ; at higher fluences (10{sup 13} ions/cm{sup 2}) a homogeneous mixed interlayer appears ; and at even higher fluences (some 10{sup 13} ions/cm{sup 2}) a preferential diffusion of Ni into Ti is clearly seen. The characterization techniques used are: (1) electrical resistivity measurements which allow to follow in situ the damage kinetic. (II) neutron and X-ray reflectometry. (III) elaboration of transverse cuts on which was performed energy loss spectroscopy. (II) and (III) allow the determination of the concentration profiles of the different species present in the sample. (IV) transmission electron microscopy on the transverse cuts which gives a direct image of the different layers. (author). 11 refs., 103 figs., 23 tabs., 2 appends.

  6. Heavy ion collisions at intermediate energy

    International Nuclear Information System (INIS)

    Bertsch, G.; Amsden, A.A.

    1978-01-01

    Two types of measurement are proposed for the analysis of heavy ion collisions in the range of energy of 20--200 MeV/A. First, measurement of the longitudinal component of the kinetic energy of the collision products characterizes the impact parameter of the collision. The distribution in this quantity allows the dissipation in the theoretical models to be determined. A second kind of measurement is that of the coefficients of a spherical harmonic expansion of the angular distribution of the products. Besides giving independent information on the impact parameter and reaction dynamics, measurement of these coefficients offers the possibility of measuring the stiffness of the equation of state of nuclear matter. These ideas are explored in the context of a hydrodynamic model for the collision. In the purely hydrodynamic model there is a large measurable asymmetry in the angular distribution, but the dependence on the equation of state is small

  7. The heavy ion injection scheme for RHIC [Relativistic Heavy Ion Collider

    International Nuclear Information System (INIS)

    Rhoades-Brown, M.J.

    1989-01-01

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven has a multi-component injection system. The Collider requires very heavy ions such as 79 197 Au to be injected fully stripped of atomic electrons, at a kinetic energy of approximately 10 GeV/nucleon. However, the heavy ions are produced initially at a negative ion source and accelerated first in a 15 MV Tandem. These partially stripped ions have a kinetic energy of approximately 1 MeV/nucleon on leaving the Tandem. In order to achieve the injection requirements for RHIC, the partially stripped ions are accelerated in the Booster (currently under construction) and pass through a stripping foil on their way to the Alternating Gradient Synchrotron (AGS), where they are further accelerated before injection into RHIC. Recent theoretical calculations have shown quite convincingly that very heavy ions with 2 electrons in the filled K-shell may be accelerated with negligible loss in the AGS. 13 refs., 3 figs., 3 tabs

  8. Fully kinetic simulations of megajoule-scale dense plasma focus

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, A.; Link, A.; Tang, V.; Halvorson, C.; May, M. [Lawrence Livermore National Laboratory, Livermore California 94550 (United States); Welch, D. [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States); Meehan, B. T.; Hagen, E. C. [National Security Technologies, LLC, Las Vegas, Nevada 89030 (United States)

    2014-10-15

    Dense plasma focus (DPF) Z-pinch devices are sources of copious high energy electrons and ions, x-rays, and neutrons. Megajoule-scale DPFs can generate 10{sup 12} neutrons per pulse in deuterium gas through a combination of thermonuclear and beam-target fusion. However, the details of the neutron production are not fully understood and past optimization efforts of these devices have been largely empirical. Previously, we reported on the first fully kinetic simulations of a kilojoule-scale DPF and demonstrated that both kinetic ions and kinetic electrons are needed to reproduce experimentally observed features, such as charged-particle beam formation and anomalous resistivity. Here, we present the first fully kinetic simulation of a MegaJoule DPF, with predicted ion and neutron spectra, neutron anisotropy, neutron spot size, and time history of neutron production. The total yield predicted by the simulation is in agreement with measured values, validating the kinetic model in a second energy regime.

  9. Concepts of radial and angular kinetic energies

    DEFF Research Database (Denmark)

    Dahl, Jens Peder; Schleich, W.P.

    2002-01-01

    We consider a general central-field system in D dimensions and show that the division of the kinetic energy into radial and angular parts proceeds differently in the wave-function picture and the Weyl-Wigner phase-space picture, Thus, the radial and angular kinetic energies are different quantities...

  10. Quantitative evaluation of high-energy O- ion particle flux in a DC magnetron sputter plasma with an indium-tin-oxide target

    Science.gov (United States)

    Suyama, Taku; Bae, Hansin; Setaka, Kenta; Ogawa, Hayato; Fukuoka, Yushi; Suzuki, Haruka; Toyoda, Hirotaka

    2017-11-01

    O- ion flux from the indium tin oxide (ITO) sputter target under Ar ion bombardment is quantitatively evaluated using a calorimetry method. Using a mass spectrometer with an energy analyzer, O- energy distribution is measured with spatial dependence. Directional high-energy O- ion ejected from the target surface is observed. Using a calorimetry method, localized heat flux originated from high-energy O- ion is measured. From absolute evaluation of the heat flux from O- ion, O- particle flux in order of 1018 m-2 s-1 is evaluated at a distance of 10 cm from the target. Production yield of O- ion on the ITO target by one Ar+ ion impingement at a kinetic energy of 244 eV is estimated to be 3.3  ×  10-3 as the minimum value.

  11. Adsorption kinetics of ion of Pb2+ using Tricalcium Phosphate particles

    Science.gov (United States)

    Fadli, A.; Yenti, S. R.; Akbar, F.; Maihendra; Mawarni, F.

    2018-04-01

    One of the heavy metals that can pollute water is Pb2+. The concentration of ion Pb2+ can be removed using the adsorption method. The purpose of this research is to determine the adsorption kinetics model of ions Pb2+ using tricalcium phosphate (TCP) particles with variation of the temperature and adsorbent dosage. Five hundred mililiter Pb2+ solution with of 3 mg/L were added 0,5 gr, 1 gr and 1,5 gr of TCP in a glass beaker and stirred with rate of 300 rpm at a temperature of 30 °C, 40 °C and 50 °C. Pb2+ concentration in solution was analyzed by AAS (Atomic Adsorption Spectroscopy). The results showed that the rate of adsorption increased with the increasing of the temperature and adsorbent dosage. Minimum constant value of adsorption kinetic was 1,720 g/mg.min obtained at temperature of 30 °C and adsorbent dosageof 0,5 gr. The maximum value of adsorption kinetic constant was 9,755 g/mg.min obtained at temperature of 50 °C and adsorbent dosage of 1,5 gr. The appropriate model for adsorption kinetics followed the pseudo second order.

  12. Fission-fragment angular distributions and total kinetic energies for 235U(n,f) from .18 to 8.83 MeV

    International Nuclear Information System (INIS)

    Meadows, J.W.; Budtz-Joergensen, C.

    1982-01-01

    A gridded ion chamber was used to measure the fission fragment angular distribution and total kinetic energy for the 235 U(n,f) reaction from 0.18 to 8.81 MeV neutron energy. The anisotropies are in generally good agreement with earlier measurements. The average total kinetic energy is approx. 0.2 MeV greater than the thermal value at neutron energies < 2 MeV and shows a sudden decrease of approx. 0.8 MeV between 4 and 5 MeV neutron energy, well below the (n, n'f) threshold. Possible causes of this decrease are a change in the mass distribution or decreased shell effects in the heavy fragment

  13. Live cell imaging combined with high-energy single-ion microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Na; Du, Guanghua, E-mail: gh-du@impcas.ac.cn; Liu, Wenjing; Wu, Ruqun; Wei, Junzhe [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Guo, Jinlong [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Northwest Normal University, Lanzhou (China); Chen, Hao [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Institute of Nuclear Science and Technology, University of Lanzhou, Lanzhou (China)

    2016-03-15

    DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10{sup −3} s{sup −1} and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10{sup −2} s{sup −1}.

  14. Live cell imaging combined with high-energy single-ion microbeam

    International Nuclear Information System (INIS)

    Guo, Na; Du, Guanghua; Liu, Wenjing; Wu, Ruqun; Wei, Junzhe; Guo, Jinlong; Chen, Hao

    2016-01-01

    DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10"−"3 s"−"1 and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10"−"2 s"−"1.

  15. Low energy ion implantation and high energy heavy ion irradiation in C60 films

    International Nuclear Information System (INIS)

    Narayanan, K.L.; Yamaguchi, M.; Dharmarasu, N.; Kojima, N.; Kanjilal, D.

    2001-01-01

    C 60 films have been bombarded with low energy boron ions and high energy swift heavy ions (SHI) of silver and oxygen at different doses. Raman scattering and Fourier transform infrared (FTIR) studies were carried out on the virgin and irradiated films and the results are in good agreement with each other. The films subject to low energy boron ion implantation showed destruction of the bukky balls whereas the films subject to high energy ion irradiation did not show appreciable effects on their structure. These results indicate that C 60 films are more prone to defects by elastic collision and subsequent implantation at lower energy. Irradiation at higher energy was less effective in creating appreciable defects through electronic excitation by inelastic collisions at similar energy density

  16. Fisher information, kinetic energy and uncertainty relation inequalities

    International Nuclear Information System (INIS)

    Luo Shunlong

    2002-01-01

    By interpolating between Fisher information and mechanical kinetic energy, we introduce a general notion of kinetic energy with respect to a parameter of Schroedinger wavefunctions from a statistical inference perspective. Kinetic energy is the sum of Fisher information and an integral of a parametrized analogue of quantum mechanical current density related to phase. A family of integral inequalities concerning kinetic energy and moments are established, among which the Cramer-Rao inequality and the Weyl-Heisenberg inequality, are special cases. In particular, the integral inequalities involving the negative order moments are relevant to the study of electron systems. Moreover, by specifying the parameter to a scale, we obtain a family of inequalities of uncertainty relation type which incorporate the position and momentum observables symmetrically in a single quantity. (author)

  17. Li+ solvation and kinetics of Li+-BF4-/PF6- ion pairs in ethylene carbonate. A molecular dynamics study with classical rate theories

    Science.gov (United States)

    Chang, Tsun-Mei; Dang, Liem X.

    2017-10-01

    Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ethylene carbonate (EC) exchange process between the first and second solvation shells around Li+ and the dissociation kinetics of ion pairs Li+-[BF4] and Li+-[PF6] in this solvent. We calculate the exchange rates using transition state theory and correct them with transmission coefficients computed by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found that the residence times of EC around Li+ ions varied from 60 to 450 ps, depending on the correction method used. We found that the relaxation times changed significantly from Li+-[BF4] to Li+-[PF6] ion pairs in EC. Our results also show that, in addition to affecting the free energy of dissociation in EC, the anion type also significantly influences the dissociation kinetics of ion pairing.

  18. Kinetic and Thermodynamic Studies for the Removal of Europium Ions from Waste Solution Using Some Local Clay Minerals

    International Nuclear Information System (INIS)

    El-Kamash, A.M.; El-Masry, E.H.; El-Dessouky, M.I.

    2008-01-01

    Thermodynamic and kinetic investigations on the removal of Eu 3+ ions from aqueous waste solution using bentonite and sandstone, as local clay minerals, has been done using batch technique. The influences of ph, contact time between liquid and solid phases, initial metal ion concentration, and temperature have been evaluated. Pseudo first-order and pseudo second-order kinetic models were used to analyze the sorption rate data and the results showed that the pseudo second-order model is best correlate the kinetic data. Equilibrium isotherms were determined to assess the maximum sorption capacity of bentonite and sandstone and the equilibrium sorption data were analyzed using Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. All tested models fit the data reasonably well in terms of regression coefficients. The maximum sorption capacity of bentonite was found to be greater than that of sandstone and the mean free energy is in all cases in the range corresponding to the ion exchange type of sorption. Sorption studies were also performed at different temperatures to obtain the thermodynamic parameters of the process. The numerical value of δG degree decreases with an increase in temperature, indicating that the sorption reaction is more favorable at higher temperature. The positive values of δH degree correspond to the endothermic nature of the sorption process

  19. Mass and kinetic-energy distributions of fragments formed in the heavy-ion-induced fission of 208Po

    International Nuclear Information System (INIS)

    Cuninghame, J.G.; Goodall, J.A.B.

    1980-01-01

    Fission fragments following the decay of a 208 Po compound nucleus have been observed by using radiochemical and particle-counting techniques. The (α+ 204 Pb), ( 12 C+ 196 Pt) and ( 16 O+ 192 Os) reactions were studied at two or three bombarding energies, covering overlapping ranges of excitation energies. - Radiochemical separations of As, Br, Y, Nb, Tc, Ag, Sb and I isotopes were made from catcher foils sandwiching isotopic targets, and their isotopic yield distributions determined. The distributions are used to estimate the average number of neutrons associated with each fission event, including neutrons emitted before and after fission. - Prompt coincidence measurements of fragments are used to derive the overall mass and kinetic-energy distributions of primary fragments, taking into account the effects of pre- and post-fission neutron emission. The mass distributions are well fitted by the statistical theory, at a temperature corresponding to an excitation about 10 MeV above that at the saddle point. No evidence is found for an increase of kinetic-energy with increasing angular momentum of the compound nucleus. (author)

  20. Gyrokinetic Electron and Fully Kinetic Ion Particle Simulation of Collisionless Plasma Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Yu Lin; Xueyi Wang; Liu Chen; Zhihong Lin

    2009-08-11

    Fully kinetic-particle simulations and hybrid simulations have been utilized for decades to investigate various fundamental plasma processes, such as magnetic reconnection, fast compressional waves, and wave-particle interaction. Nevertheless, due to disparate temporal and spatial scales between electrons and ions, existing fully kinetic-particle codes have to employ either unrealistically high electron-to-ion mass ratio, me/mi, or simulation domain limited to a few or a few ten's of the ion Larmor radii, or/and time much less than the global Alfven time scale in order to accommodate available computing resources. On the other hand, in the hybrid simulation, the ions are treated as fully kinetic particles but the electrons are treated as a massless fluid. The electron kinetic effects, e.g., wave-particle resonances and finite electron Larmor radius effects, are completely missing. Important physics, such as the electron transit time damping of fast compressional waves or the triggering mechanism of magnetic reconnection in collisionless plasmas is absent in the hybrid codes. Motivated by these considerations and noting that dynamics of interest to us has frequencies lower than the electron gyrofrequency, we planned to develop an innovative particle simulation model, gyrokinetic (GK) electrons and fully kinetic (FK) ions. In the GK-electron and FK-ion (GKe/FKi) particle simulation model, the rapid electron cyclotron motion is removed, while keeping finite electron Larmor radii, realistic me/mi ratio, wave-particle interactions, and off-diagonal components of electron pressure tensor. The computation power can thus be significantly improved over that of the full-particle codes. As planned in the project DE-FG02-05ER54826, we have finished the development of the new GK-electron and FK-ion scheme, finished its benchmark for a uniform plasma in 1-D, 2-D, and 3-D systems against linear waves obtained from analytical theories, and carried out a further convergence

  1. Gyrokinetic Electron and Fully Kinetic Ion Particle Simulation of Collisionless Plasma Dynamics

    International Nuclear Information System (INIS)

    Lin, Yu; Wang, Xueyi; Chen, Liu; Lin, Zhihong

    2009-01-01

    Fully kinetic-particle simulations and hybrid simulations have been utilized for decades to investigate various fundamental plasma processes, such as magnetic reconnection, fast compressional waves, and wave-particle interaction. Nevertheless, due to disparate temporal and spatial scales between electrons and ions, existing fully kinetic-particle codes have to employ either unrealistically high electron-to-ion mass ratio, me/mi, or simulation domain limited to a few or a few ten's of the ion Larmor radii, or/and time much less than the global Alfven time scale in order to accommodate available computing resources. On the other hand, in the hybrid simulation, the ions are treated as fully kinetic particles but the electrons are treated as a massless fluid. The electron kinetic effects, e.g., wave-particle resonances and finite electron Larmor radius effects, are completely missing. Important physics, such as the electron transit time damping of fast compressional waves or the triggering mechanism of magnetic reconnection in collisionless plasmas is absent in the hybrid codes. Motivated by these considerations and noting that dynamics of interest to us has frequencies lower than the electron gyrofrequency, we planned to develop an innovative particle simulation model, gyrokinetic (GK) electrons and fully kinetic (FK) ions. In the GK-electron and FK-ion (GKe/FKi) particle simulation model, the rapid electron cyclotron motion is removed, while keeping finite electron Larmor radii, realistic me/mi ratio, wave-particle interactions, and off-diagonal components of electron pressure tensor. The computation power can thus be significantly improved over that of the full-particle codes. As planned in the project DE-FG02-05ER54826, we have finished the development of the new GK-electron and FK-ion scheme, finished its benchmark for a uniform plasma in 1-D, 2-D, and 3-D systems against linear waves obtained from analytical theories, and carried out a further convergence test

  2. Energy conversion through mass loading of escaping ionospheric ions for different Kp values

    Directory of Open Access Journals (Sweden)

    M. Yamauchi

    2018-01-01

    Full Text Available By conserving momentum during the mixing of fast solar wind flow and slow planetary ion flow in an inelastic way, mass loading converts kinetic energy to other forms – e.g. first to electrical energy through charge separation and then to thermal energy (randomness through gyromotion of the newly born cold ions for the comet and Mars cases. Here, we consider the Earth's exterior cusp and plasma mantle, where the ionospheric origin escaping ions with finite temperatures are loaded into the decelerated solar wind flow. Due to direct connectivity to the ionosphere through the geomagnetic field, a large part of this electrical energy is consumed to maintain field-aligned currents (FACs toward the ionosphere, in a similar manner as the solar wind-driven ionospheric convection in the open geomagnetic field region. We show that the energy extraction rate by the mass loading of escaping ions (ΔK is sufficient to explain the cusp FACs, and that ΔK depends only on the solar wind velocity accessing the mass-loading region (usw and the total mass flux of the escaping ions into this region (mloadFload, as ΔK ∼ −mloadFloadu2sw∕4. The expected distribution of the separated charges by this process also predicts the observed flowing directions of the cusp FACs for different interplanetary magnetic field (IMF orientations if we include the deflection of the solar wind flow directions in the exterior cusp. Using empirical relations of u0 ∝ Kp + 1.2 and Fload ∝ exp(0.45Kp for Kp = 1–7, where u0 is the solar wind velocity upstream of the bow shock, ΔK becomes a simple function of Kp as log10(ΔK = 0.2 ⋅ Kp + 2 ⋅ log10(Kp + 1.2 + constant. The major contribution of this nearly linear increase is the Fload term, i.e. positive feedback between the increase of ion escaping rate Fload through the increased energy consumption in the ionosphere for high Kp, and subsequent extraction of more kinetic energy

  3. Quantitative evaluation of high-energy O− ion particle flux in a DC magnetron sputter plasma with an indium-tin-oxide target

    International Nuclear Information System (INIS)

    Suyama, Taku; Bae, Hansin; Setaka, Kenta; Ogawa, Hayato; Fukuoka, Yushi; Suzuki, Haruka; Toyoda, Hirotaka

    2017-01-01

    O − ion flux from the indium tin oxide (ITO) sputter target under Ar ion bombardment is quantitatively evaluated using a calorimetry method. Using a mass spectrometer with an energy analyzer, O − energy distribution is measured with spatial dependence. Directional high-energy O − ion ejected from the target surface is observed. Using a calorimetry method, localized heat flux originated from high-energy O − ion is measured. From absolute evaluation of the heat flux from O − ion, O − particle flux in order of 10 18 m −2 s −1 is evaluated at a distance of 10 cm from the target. Production yield of O − ion on the ITO target by one Ar + ion impingement at a kinetic energy of 244 eV is estimated to be 3.3  ×  10 −3 as the minimum value. (paper)

  4. Observation of luminescent spectra in low energy ion-neutral collisions. Progress report, June 1, 1976--May 31, 1978

    International Nuclear Information System (INIS)

    Leventhal, J.J.

    1978-01-01

    The experiments reported provide detailed information on the fundamental nature of energy transfer processes in ion-molecule or atom-molecule collisions. By combining ion beam techniques with emission spectroscopy, data are obtained which directly lead to internal energy state distributions of atomic and molecular products of these collisions. Data are in the form of emission spectra from nascent energetically excited species formed in the energy transfer process. Changes in the collision-produced spectra as a function of beam kinetic energy yield information on the extent of energy conversion (kinetic → internal) in the collision process. Some of the specific energy transfer processes studied are applicable to the problem of achieving inverted energy level populations in high pressure gas lasers. Also discussed are experiments designed to test theoretical models which predict product energy partitioning in molecular collisions. Because experimentally determined energy state distributions deviate substantially from the predicted distributions it is concluded that additional theoretical work is needed. A simple model was developed which qualitatively reproduces the important features of the data. This model, which is considerably more general than those previously available is outlined and briefly discussed

  5. ECR ion source based low energy ion beam facility

    Indian Academy of Sciences (India)

    Mass analyzed highly charged ion beams of energy ranging from a few keV to a few MeV plays an important role in various aspects of research in modern physics. In this paper a unique low energy ion beam facility (LEIBF) set up at Nuclear Science Centre (NSC) for providing low and medium energy multiply charged ion ...

  6. Adsorption behaviour and kinetics of exchange of Zn2+ and Eu3+ ions on a composite ion exchanger

    International Nuclear Information System (INIS)

    Morcos, T.N.

    2007-01-01

    Equilibria and kinetics of exchange of both Zn2+ and Eu3+ ions on a composite ion-exchanger, cobalt hexacyanocobaltate (III) (CoHCC) incorporated in polyacrylonitrile (PAN), has been studied. The apparent capacity of CoHCC-PAN for Zn2+ and Eu3+ was determined and found to be 0.353 and 0.69 meq/g, respectively. The higher capacity for Eu3+ ions than that for Zn2+ ions is due to the higher electrostatic interaction strength of the higher charge ion with the surface. Freundlich and Langmiur adsorption isotherms were used to investigate solute (Zn2+ or Eu3+) exchange phenomenon at the liquid/solid interface. The results indicated that both Langmuir and Freundlich isotherms fit well for both Zn2+ and Eu3+. Sorption data have been also treated with the Dubinin-Radushkevich equation. The kinetics of Zn2+ or Eu3+ sorption on the composite seems to show that the reaction was proceed via two steps. The first one was fast and probably due to adsorption followed by a slow exchange reaction. In view of the data obtained on the effect of particle size and metal ion concentrations on the rate of exchange reaction, it is concluded that the mechanism for both ions was chemical control. Generally, it seems that there are two exchange sites chemically equivalent but present in pores of different sizes which lead to different degrees of dehydration of the ions sorbed on the two sites

  7. Interaction of low-energy highly charged ions with matter; Wechselwirkung niederenergetischer hochgeladener Ionen mit Materie

    Energy Technology Data Exchange (ETDEWEB)

    Ginzel, Rainer

    2010-06-09

    The thesis presented herein deals with experimental studies of the interaction between highly charged ions and neutral matter at low collision energies. The energy range investigated is of great interest for the understanding of both charge exchange reactions between ions comprising the solar wind and various astrophysical gases, as well as the creation of near-surface nanostructures. Over the course of this thesis an experimental setup was constructed, capable of reducing the kinetic energy of incoming ions by two orders of magnitude and finally focussing the decelerated ion beam onto a solid or gaseous target. A coincidence method was employed for the simultaneous detection of photons emitted during the charge exchange process together with the corresponding projectile ions. In this manner, it was possible to separate reaction channels, whose superposition presumably propagated large uncertainties and systematic errors in previous measurements. This work has unveiled unexpectedly strong contributions of slow radiative decay channels and clear evidence of previously only postulated decay processes in charge exchange-induced X-ray spectra. (orig.)

  8. Medium energy ion scattering (MEIS)

    International Nuclear Information System (INIS)

    Dittmann, K.; Markwitz, A.

    2009-01-01

    This report gives an overview about the technique and experimental study of medium energy ion scattering (MEIS) as a quantitative technique to determine and analyse the composition and geometrical structure of crystalline surfaces and near surface-layers by measuring the energy and yield of the backscattered ions. The use of a lower energy range of 50 to 500 keV accelerated ions impinging onto the target surface and the application of a high-resolution electrostatic energy analyser (ESA) makes medium energy ion scattering spectroscopy into a high depth resolution and surface-sensitive version of RBS with less resulting damage effects. This report details the first steps of research in that field of measurement technology using medium energetic backscattered ions detected by means of a semiconductor radiation detector instead of an ESA. The study of medium energy ion scattering (MEIS) has been performed using the 40 keV industrial ion implanter established at GNS Sciences remodelled with supplementary high voltage insulation for the ion source in order to apply voltages up to 45 kV, extra apertures installed in the beamline and sample chamber in order to set the beam diameter accurately, and a semiconductor radiation detector. For measurement purposes a beam of positive charged helium ions accelerated to an energy of about 80 keV has been used impinging onto target surfaces of lead implanted into silicon (PbSi), scandium implanted into aluminium (ScAl), aluminium foil (Al) and glassy carbon (C). First results show that it is possible to use the upgraded industrial implanter for medium energy ion scattering. The beam of 4 He 2+ with an energy up to 88 keV has been focussed to 1 mm in diameter. The 5 nA ion beam hit the samples under 2 x 10 -8 mbar. The results using the surface barrier detector show scattering events from the samples. Cooling of the detector to liquid nitrogen temperatures reduced the electronic noise in the backscattering spectrum close to zero. A

  9. Polarographic investigation of complexing kinetics of polyacrylate anions with cadmium ions

    International Nuclear Information System (INIS)

    Avlyanov, Zh.K.; Kabanov, N.M.; Zezin, A.B.; Askarov, M.A.

    1990-01-01

    The processes which occur during the reduction of cadmium ions from polymer-metallic complexes (PMC) are studied for the purposes of polarographic investigation of complexing kinetics of polyacrylate anions (PAA) of different molecular masses with cadmium ions in KCl aqueous solutions. An expression is derived for establishing semiwave potential. PMC formation and dissociation reduction rate constants are calculated. It is shown that intramolecular reorderings required for the formation of a two-coordinate complex proceed much slower as compared to the diffusion of free ions

  10. Resolving key heavy-ion fusion target issues with relativistic heavy-ion research accelerators

    International Nuclear Information System (INIS)

    Arnold, R.C.

    1988-01-01

    Heavy-ion accelerators designed for relativistic nuclear research experiments can also be adapted for target research in heavy-ion driver inertial fusion. Needle-shaped plasmas can be created that are adequate for studying basic properties of matter at high energy density. Although the ion range is very long, the specific deposited power nevertheless increases with kinetic energy, as the focus spot can be made smaller and more ions can be accumulated in larger rings

  11. Ionoluminescence properties of polystyrene-hosted fluorophore films induced by helium ions of energy 50-350 keV

    Science.gov (United States)

    Chakraborty, Subha; Huang, Mengbing

    2017-10-01

    We report on measurements and analysis of ionoluminescence properties of pure polystyrene films and polystyrene films doped with four types of fluorophores in low kinetic energies (50-350 keV) of ion irradiation. We have developed a theoretical model to understand the experimentally observed ionoluminescence behaviors in terms of scintillation yield from individual ion tracks, photophysical energy transfer mechanisms, and irradiation-induced defects. A comparison of the model and experimental results suggests that singlet up-conversion resulting from triplet-triplet annihilation processes may be responsible for enhanced singlet emission of the fluorophores at high ion beam flux densities. Energy transfer from the polystyrene matrix to the fluorophore molecules has been identified as an effective pathway to increasing the fluorescence efficiency in the doped scintillator films.

  12. Experimental study of the efficiency of transformation of the dense plasma hypersonic flow kinetic energy into a radiation

    International Nuclear Information System (INIS)

    Kamrukov, A.S.; Kozlov, N.P.; Myshelov, E.P.; Protasov, Yu.S.

    1981-01-01

    Analysis of physical specific features of radiator where plasma heating is performed with tbermalization of directed kinetic energy of dense plasma flows accelerated electrodynamically up to hypersonic velocities during its shock deceleration, is given. It is shown that the plasma heating method considered has a number of principle advantages as compared with methods most disseminated now for generation of dense intensively radiating plasma (current heating exploding method) and suggests new possibilities for construction of selective high brightness radiat.ion sources of ultraviolet and far vacuum ultraviolet ranges of spectrum. Radiation gas dynamic processes of hypersonic plasma flow deceleration formed with magnetoplasma compressors have been experimentally investigated on their interaction with condenced matters in vacuum and basic thermodynamic parameters of shock compressed plasma have been determined. It is shown that the conversion process of kinetic energy of high-velocity plasma flows to radiation is accomplished at very high efficiency-integral luminescence of shock compressed plasma can reach approximately 90% of initial kinetic energy of flow [ru

  13. Kinetic energy budgets near the turbulent/nonturbulent interface in jets

    Science.gov (United States)

    Taveira, Rodrigo R.; da Silva, Carlos B.

    2013-01-01

    The dynamics of the kinetic energy near the turbulent/nonturbulent (T/NT) interface separating the turbulent from the irrotational flow regions is analysed using three direct numerical simulations of turbulent planar jets, with Reynolds numbers based on the Taylor micro-scale across the jet shear layer in the range Reλ ≈ 120-160. Important levels of kinetic energy are already present in the irrotational region near the T/NT interface. The mean pressure and kinetic energy are well described by the Bernoulli equation in this region and agree with recent results obtained from rapid distortion theory in the turbulent region [M. A. C. Teixeira and C. B. da Silva, "Turbulence dynamics near a turbulent/non-turbulent interface," J. Fluid Mech. 695, 257-287 (2012)], 10.1017/jfm.2012.17 while the normal Reynolds stresses agree with the theoretical predictions from Phillips ["The irrotational motion outside a free turbulent boundary," Proc. Cambridge Philos. Soc. 51, 220 (1955)], 10.1017/S0305004100030073. The use of conditional statistics in relation to the distance from the T/NT interface allow a detailed study of the build up of kinetic energy across the T/NT interface, pointing to a very different picture than using classical statistics. Conditional kinetic energy budgets show that apart from the viscous dissipation of kinetic energy, the maximum of all the mechanisms governing the kinetic energy are concentrated in a very narrow region distancing about one to two Taylor micro-scales from the T/NT interface. The (total and fluctuating) kinetic energy starts increasing in the irrotational region by pressure-velocity interactions - a mechanism that can act at distance, and continue to grow by advection (for the total kinetic energy) and turbulent diffusion (for the turbulent kinetic energy) inside the turbulent region. These mechanisms tend to occur preferentially around the core of the large-scale vortices existing near T/NT interface. The production of turbulent

  14. In Situ Tracking Kinetic Pathways of Li+/Na+ Substitution during Ion-Exchange Synthesis of LixNa1.5-xVOPO4F0.5.

    Science.gov (United States)

    Park, Young-Uk; Bai, Jianming; Wang, Liping; Yoon, Gabin; Zhang, Wei; Kim, Hyungsub; Lee, Seongsu; Kim, Sung-Wook; Looney, J Patrick; Kang, Kisuk; Wang, Feng

    2017-09-13

    Ion exchange is a ubiquitous phenomenon central to wide industrial applications, ranging from traditional (bio)chemical separation to the emerging chimie douce synthesis of materials with metastable structure for batteries and other energy applications. The exchange process is complex, involving substitution and transport of different ions under non-equilibrium conditions, and thus difficult to probe, leaving a gap in mechanistic understanding of kinetic exchange pathways toward final products. Herein, we report in situ tracking kinetic pathways of Li + /Na + substitution during solvothermal ion-exchange synthesis of Li x Na 1.5-x VOPO 4 F 0.5 (0 ≤ x ≤ 1.5), a promising multi-Li polyanionic cathode for batteries. The real-time observation, corroborated by first-principles calculations, reveals a selective replacement of Na + by Li + , leading to peculiar Na + /Li + /vacancy orderings in the intermediates. Contradicting the traditional belief of facile topotactic substitution via solid solution reaction, an abrupt two-phase transformation occurs and predominantly governs the kinetics of ion exchange and transport in the 1D polyanionic framework, consequently leading to significant difference of Li stoichiometry and electrochemical properties in the exchanged products. The findings may help to pave the way for rational design of ion exchange synthesis for making new materials.

  15. Warm ion effects on kinetic drift cyclotron loss cone instabilities

    International Nuclear Information System (INIS)

    Guo Shichong; Shen Jiewu; Cai Shidong

    1988-01-01

    The effects of adding warm plasmas on the kinetic DCLC mode in high β loss cone plasmas are investigated in detail. It is found that when the fluid DCLC mode is stabilized by a small amount of warm plasma, the kinetic excitation still remains due to two different mechanisms, namely, (1) magnetic drift resonance dissipation excites the negative energy wave; (2) a new type of positive energy wave can become unstable as the resonance condition is met. Comparing with fluid approximation theory, more warm plasmas are needed to suppress the kinetic DCLC instabilities

  16. Cross-beam energy transfer: On the accuracy of linear stationary models in the linear kinetic regime

    Science.gov (United States)

    Debayle, A.; Masson-Laborde, P.-E.; Ruyer, C.; Casanova, M.; Loiseau, P.

    2018-05-01

    We present an extensive numerical study by means of particle-in-cell simulations of the energy transfer that occurs during the crossing of two laser beams. In the linear regime, when ions are not trapped in the potential well induced by the laser interference pattern, a very good agreement is obtained with a simple linear stationary model, provided the laser intensity is sufficiently smooth. These comparisons include different plasma compositions to cover the strong and weak Landau damping regimes as well as the multispecies case. The correct evaluation of the linear Landau damping at the phase velocity imposed by the laser interference pattern is essential to estimate the energy transfer rate between the laser beams, once the stationary regime is reached. The transient evolution obtained in kinetic simulations is also analysed by means of a full analytical formula that includes 3D beam energy exchange coupled with the ion acoustic wave response. Specific attention is paid to the energy transfer when the laser presents small-scale inhomogeneities. In particular, the energy transfer is reduced when the laser inhomogeneities are comparable with the Landau damping characteristic length of the ion acoustic wave.

  17. Kinetic studies of uranyl ion adsorption on acrylonitrile (AN) / polyethylene glycol (PEG) interpenetrating networks (IPN)

    International Nuclear Information System (INIS)

    Aycik, G.A.; Gurellier, R.

    2004-01-01

    The kinetics of the adsorption of uranyl ions on amidoximated acrylonitrile (AN)/ polyethylene glycol (PEG) interpenetrating network (IPNs) from aqueous solutions was studied as a function of time and temperature. Adsorption analyses were performed for definite uranyl ion concentrations of 1x10 -2 M and at four different temperatures as 290K, 298K, 308K and 318K. Adsorption time was increased from zero to 48 hours. Adsorption capacities of uranyl ions by PEG/AN IPNS were determined by gamma spectrometer. The results indicate that adsorption capacity increases linearly with increasing temperature. The max adsorption capacity was found as 602 mgu/g IPN at 308K. Adsorption rate was evaluated from the curve plotted of adsorption capacity versus time, for each temperature. Rate constants for uranyl ions adsorption on amidoximated ipns were calculated for 290K, 298K, 308K and 318K at the solution concentration of 1x10 -2 M . The results showed that as the temperature increases the rate constant increases exponentially too. The mean activation energy of uranyl ions adsorption was found as 34.6 kJ/mole by using arrhenius equation. (author)

  18. An Ab Initio and Kinetic Monte Carlo Simulation Study of Lithium Ion Diffusion on Graphene

    Directory of Open Access Journals (Sweden)

    Kehua Zhong

    2017-07-01

    Full Text Available The Li+ diffusion coefficients in Li+-adsorbed graphene systems were determined by combining first-principle calculations based on density functional theory with Kinetic Monte Carlo simulations. The calculated results indicate that the interactions between Li ions have a very important influence on lithium diffusion. Based on energy barriers directly obtained from first-principle calculations for single-Li+ and two-Li+ adsorbed systems, a new equation predicting energy barriers with more than two Li ions was deduced. Furthermore, it is found that the temperature dependence of Li+ diffusion coefficients fits well to the Arrhenius equation, rather than meeting the equation from electrochemical impedance spectroscopy applied to estimate experimental diffusion coefficients. Moreover, the calculated results also reveal that Li+ concentration dependence of diffusion coefficients roughly fits to the equation from electrochemical impedance spectroscopy in a low concentration region; however, it seriously deviates from the equation in a high concentration region. So, the equation from electrochemical impedance spectroscopy technique could not be simply used to estimate the Li+ diffusion coefficient for all Li+-adsorbed graphene systems with various Li+ concentrations. Our work suggests that interactions between Li ions, and among Li ion and host atoms will influence the Li+ diffusion, which determines that the Li+ intercalation dependence of Li+ diffusion coefficient should be changed and complex.

  19. Kinetics and mechanism of furfural oxidation by ions of heterovalent metals

    Energy Technology Data Exchange (ETDEWEB)

    Krupenskij, V.I. (Ukhtinskij Industrial' nyj Inst. (USSR))

    1983-01-01

    Real constants of rate of furfural oxidation by Cu/sup 2 +/, Fe/sup 3 +/, Ce/sup 4 +/, Ag/sup +/, Hg/sup 2 +//sub 2/ ions are determined, other kinetic and activation parameters of reactions are calculated, constants of stability and other thermodynamic characteristics of furfural complex with cations-oxidizers are found. Schemes of furfural transformations at one- and two-electron oxidation by ions of variable-valency metals are suggested.

  20. The ion polytropic coefficient in a collisionless sheath containing hot ions

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Binbin; Xiang, Nong, E-mail: xiangn@ipp.ac.cn; Ou, Jing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China)

    2016-08-15

    The fluid approach has been widely used to study plasma sheath dynamics. For a sheath containing hot ions whose temperature is greater than the electron's, how to truncate the fluid hierarchy chain equations while retaining to the fullest extent of the kinetic effects is always a difficult problem. In this paper, a one-dimensional, collisionless sheath containing hot ions is studied via particle-in-cell simulations. By analyzing the ion energy equation and taking the kinetic effects into account, we have shown that the ion polytropic coefficient in the vicinity of the sheath edge is approximately constant so that the state equation with the modified polytropic coefficient can be used to close the hierarchy chain of the ion fluid equations. The value of the polytropic coefficient strongly depends on the hot ion temperature and its concentration in the plasma. The semi-analytical model is given to interpret the simulation results. As an application, the kinetic effects on the ion saturation current density in the probe theory are discussed.

  1. Peapod-like Li3 VO4 /N-Doped Carbon Nanowires with Pseudocapacitive Properties as Advanced Materials for High-Energy Lithium-Ion Capacitors.

    Science.gov (United States)

    Shen, Laifa; Lv, Haifeng; Chen, Shuangqiang; Kopold, Peter; van Aken, Peter A; Wu, Xiaojun; Maier, Joachim; Yu, Yan

    2017-07-01

    Lithium ion capacitors are new energy storage devices combining the complementary features of both electric double-layer capacitors and lithium ion batteries. A key limitation to this technology is the kinetic imbalance between the Faradaic insertion electrode and capacitive electrode. Here, we demonstrate that the Li 3 VO 4 with low Li-ion insertion voltage and fast kinetics can be favorably used for lithium ion capacitors. N-doped carbon-encapsulated Li 3 VO 4 nanowires are synthesized through a morphology-inheritance route, displaying a low insertion voltage between 0.2 and 1.0 V, a high reversible capacity of ≈400 mAh g -1 at 0.1 A g -1 , excellent rate capability, and long-term cycling stability. Benefiting from the small nanoparticles, low energy diffusion barrier and highly localized charge-transfer, the Li 3 VO 4 /N-doped carbon nanowires exhibit a high-rate pseudocapacitive behavior. A lithium ion capacitor device based on these Li 3 VO 4 /N-doped carbon nanowires delivers a high energy density of 136.4 Wh kg -1 at a power density of 532 W kg -1 , revealing the potential for application in high-performance and long life energy storage devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Pairing-induced kinetic energy lowering in doped antiferromagnets

    International Nuclear Information System (INIS)

    Wrobel, P; Eder, R; Fulde, P

    2003-01-01

    We analyse lowering of the kinetic energy in doped antiferromagnets at the transition to the superconducting state. Measurements of optical conductivity indicate that such unconventional behaviour takes place in underdoped Bi-2212. We argue that the definition of the operator representing the kinetic energy is determined by experimental conditions. The thermodynamic average of that operator is related to the integrated spectral weight of the optical conductivity and thus depends on the cut-off frequency limiting that integral. If the upper limit of the integral lies below the charge transfer gap the spectral weight represents the average of the hopping term in the space restricted to the energy range below the gap. We show that the kinetic energy is indeed lowered at the superconducting transition in the t-J model (tJM), which is an effective model defined in the restricted space. That result is in agreement with experimental observations and may be attributed to the formation of spin polarons and the change of roles which are played by the kinetic and the potential energy in the tJM and in some effective model for spin polarons. The total spectral weight represents the kinetic energy in a model defined in a broader space if the upper limit in the integral of the optical conductivity is set above the gap. We demonstrate that the kinetic energy in the Hubbard model is also lowered in the superconducting state. That result does not agree with experimental observations, indicating that the spectral weight is conserved for all temperatures if the upper limit of the integral is set above the charge transfer gap. This discrepancy suggests that a single band model is not capable of describing in some respects the physics of excitations across the gap

  3. Ion-ion interaction and energy transfer of 4+ transuranium ions in cerium tetrafluoride

    International Nuclear Information System (INIS)

    Liu, G.K.; Beitz, J.V.

    1990-01-01

    Dynamics of excited 5f electron states of the transuranium ions Cm 4+ and Bk 4+ in CeF 4 are compared. Based on time- and wavelength-resolved laser-induced fluorescence, excitation energy transfer processes have been probed. Depending on concentration and electronic energy level structure of the studied 4+ transuranium ion, the dominant energy transfer mechanisms were identified as cross relaxation, exciton-exciton annihilation, and trapping. Energy transfer rates derived from the fitting of the observed fluorescence decays to theoretical models, based on electric multipolar ion-ion interactions, are contrasted with prior studies of 4f states of 3+ lanthanide and 3d states of transition metal ions. 16 refs., 1 tab

  4. Kinetic effects in the propagation of ion-acoustic negative solitons in plasmas with negative ions

    International Nuclear Information System (INIS)

    Roberto, M.

    1986-12-01

    The existence of ion-acoustic negative (rarefactive) solitons in plasmas was experimentally verified and explained by means of the Korteweg-de Vries equation, obtained from a fluid model. The experimental results obtained in a double-plasma machine of the Institute for Space Research, however, have provided values of Mach number larger than predicted by this simple model. In order to improve the analysis of the phenomenon, Kinetic effects resultant from the occurrence of reflected electrons and trapped ions in the soliton potential were considered, using the theory of Sagdeev potential. For the description of the negative ion dynamics the fluid model treatment was preserved. It was verified that the effects of the finite temperature and trapping of the positive ions modify the results predicted by the simple KdV model in such a way that the Mach number is reduced as the ion temperature increases. It was shown that reflection of electrons is consistent with the large experimental values of Mach number. (Author) [pt

  5. Mechanistic study of manganese-substituted glycerol dehydrogenase using a kinetic and thermodynamic analysis.

    Science.gov (United States)

    Fang, Baishan; Niu, Jin; Ren, Hong; Guo, Yingxia; Wang, Shizhen

    2014-01-01

    Mechanistic insights regarding the activity enhancement of dehydrogenase by metal ion substitution were investigated by a simple method using a kinetic and thermodynamic analysis. By profiling the binding energy of both the substrate and product, the metal ion's role in catalysis enhancement was revealed. Glycerol dehydrogenase (GDH) from Klebsiella pneumoniae sp., which demonstrated an improvement in activity by the substitution of a zinc ion with a manganese ion, was used as a model for the mechanistic study of metal ion substitution. A kinetic model based on an ordered Bi-Bi mechanism was proposed considering the noncompetitive product inhibition of dihydroxyacetone (DHA) and the competitive product inhibition of NADH. By obtaining preliminary kinetic parameters of substrate and product inhibition, the number of estimated parameters was reduced from 10 to 4 for a nonlinear regression-based kinetic parameter estimation. The simulated values of time-concentration curves fit the experimental values well, with an average relative error of 11.5% and 12.7% for Mn-GDH and GDH, respectively. A comparison of the binding energy of enzyme ternary complex for Mn-GDH and GDH derived from kinetic parameters indicated that metal ion substitution accelerated the release of dioxyacetone. The metal ion's role in catalysis enhancement was explicated.

  6. Mechanistic study of manganese-substituted glycerol dehydrogenase using a kinetic and thermodynamic analysis.

    Directory of Open Access Journals (Sweden)

    Baishan Fang

    Full Text Available Mechanistic insights regarding the activity enhancement of dehydrogenase by metal ion substitution were investigated by a simple method using a kinetic and thermodynamic analysis. By profiling the binding energy of both the substrate and product, the metal ion's role in catalysis enhancement was revealed. Glycerol dehydrogenase (GDH from Klebsiella pneumoniae sp., which demonstrated an improvement in activity by the substitution of a zinc ion with a manganese ion, was used as a model for the mechanistic study of metal ion substitution. A kinetic model based on an ordered Bi-Bi mechanism was proposed considering the noncompetitive product inhibition of dihydroxyacetone (DHA and the competitive product inhibition of NADH. By obtaining preliminary kinetic parameters of substrate and product inhibition, the number of estimated parameters was reduced from 10 to 4 for a nonlinear regression-based kinetic parameter estimation. The simulated values of time-concentration curves fit the experimental values well, with an average relative error of 11.5% and 12.7% for Mn-GDH and GDH, respectively. A comparison of the binding energy of enzyme ternary complex for Mn-GDH and GDH derived from kinetic parameters indicated that metal ion substitution accelerated the release of dioxyacetone. The metal ion's role in catalysis enhancement was explicated.

  7. On kinetics and mechanism of' furfural oxidation by ions of heterovalent metals

    International Nuclear Information System (INIS)

    Krupenskij, V.I.

    1983-01-01

    Real constants of rate of furfural oxidation by Cu 2+ , Fe 3+ , Ce 4+ , Ag + , Hg 2+ 2 ions are determined, other kinetic and activation parameters of reactions are calculated, constants of stability and other thermodynamic characteristics of furfural complex with cations-oxidizers are found. Schemes of furfural transformations at one- and two-electron oxidation by ions of variable-valency metals are suggested

  8. Kinetic energy budget details

    Indian Academy of Sciences (India)

    Abstract. This paper presents the detailed turbulent kinetic energy budget and higher order statistics of flow behind a surface-mounted rib with and without superimposed acoustic excitation. Pattern recognition technique is used to determine the large-scale structure magnitude. It is observed that most of the turbulence ...

  9. Unique aqueous Li-ion/sulfur chemistry with high energy density and reversibility.

    Science.gov (United States)

    Yang, Chongyin; Suo, Liumin; Borodin, Oleg; Wang, Fei; Sun, Wei; Gao, Tao; Fan, Xiulin; Hou, Singyuk; Ma, Zhaohui; Amine, Khalil; Xu, Kang; Wang, Chunsheng

    2017-06-13

    Leveraging the most recent success in expanding the electrochemical stability window of aqueous electrolytes, in this work we create a unique Li-ion/sulfur chemistry of both high energy density and safety. We show that in the superconcentrated aqueous electrolyte, lithiation of sulfur experiences phase change from a high-order polysulfide to low-order polysulfides through solid-liquid two-phase reaction pathway, where the liquid polysulfide phase in the sulfide electrode is thermodynamically phase-separated from the superconcentrated aqueous electrolyte. The sulfur with solid-liquid two-phase exhibits a reversible capacity of 1,327 mAh/(g of S), along with fast reaction kinetics and negligible polysulfide dissolution. By coupling a sulfur anode with different Li-ion cathode materials, the aqueous Li-ion/sulfur full cell delivers record-high energy densities up to 200 Wh/(kg of total electrode mass) for >1,000 cycles at ∼100% coulombic efficiency. These performances already approach that of commercial lithium-ion batteries (LIBs) using a nonaqueous electrolyte, along with intrinsic safety not possessed by the latter. The excellent performance of this aqueous battery chemistry significantly promotes the practical possibility of aqueous LIBs in large-format applications.

  10. Magnetized retarding field energy analyzer measuring the particle flux and ion energy distribution of both positive and negative ions

    International Nuclear Information System (INIS)

    Rafalskyi, Dmytro; Aanesland, Ane; Dudin, Stanislav

    2015-01-01

    This paper presents the development of a magnetized retarding field energy analyzer (MRFEA) used for positive and negative ion analysis. The two-stage analyzer combines a magnetic electron barrier and an electrostatic ion energy barrier allowing both positive and negative ions to be analyzed without the influence of electrons (co-extracted or created downstream). An optimal design of the MRFEA for ion-ion beams has been achieved by a comparative study of three different MRFEA configurations, and from this, scaling laws of an optimal magnetic field strength and topology have been deduced. The optimal design consists of a uniform magnetic field barrier created in a rectangular channel and an electrostatic barrier consisting of a single grid and a collector placed behind the magnetic field. The magnetic barrier alone provides an electron suppression ratio inside the analyzer of up to 6000, while keeping the ion energy resolution below 5 eV. The effective ion transparency combining the magnetic and electrostatic sections of the MRFEA is measured as a function of the ion energy. It is found that the ion transparency of the magnetic barrier increases almost linearly with increasing ion energy in the low-energy range (below 200 eV) and saturates at high ion energies. The ion transparency of the electrostatic section is almost constant and close to the optical transparency of the entrance grid. We show here that the MRFEA can provide both accurate ion flux and ion energy distribution measurements in various experimental setups with ion beams or plasmas run at low pressure and with ion energies above 10 eV

  11. In-medium and isospin effects on eta production in heavy-ion collisions near threshold energies

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jie; Chen, Peng-Hui [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); University of Chinese Academy of Sciences, Beijing (China); Feng, Zhao-Qing; Wang, Jian-Song [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Niu, Fei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Henan Normal University, Institute of Particle and Nuclear Physics, Xinxiang (China); Guo, Ya-Fei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China)

    2017-06-15

    The dynamics of η meson produced in heavy-ion collisions has been investigated within the Lanzhou quantum molecular dynamics model (LQMD). The in-medium corrections have been considered in the model, in which an attractive η-nucleon potential is implemented. The impacts of the η optical potential and the nuclear symmetry energy on the η dynamics are investigated. It is found that the total yields are slightly influenced by the potential and weakly depend on the symmetry energy. However, the structure of the kinetic spectra is related to the optical potential and the stiffness of symmetry energy. The attractive potential leads to the reduction of high-momentum (kinetic energy) η production, i.e., the spectra of momentum and transverse mass distributions, increasing the reabsorption process by surrounding nucleons, and favoring the in-plane eta emissions. The reabsorption process in η-nucleon collisions plays a significant role on the η dynamics. (orig.)

  12. Liquid-drop model description of heavy ion fusion at sub-barrier energies

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, C E; Barbosa, V C; Canto, L F; Donangelo, R

    1987-10-05

    The enhancement of the heavy ion fusion cross section at sub-barrier energies is studied in the liquid-drop model approach. The shape of the system is described by two spheres smoothly connected by a neck, and the kinetic and potential energies are calculated within this parametrization. Underbarrier fusion cross sections for symmetric projectile-target combinations are calculated in the WKB approximation and a comparison with the available data is made. The agreement is quite satisfactory, except for those systems in which the reaction is strongly affected by the details of the nuclear structure of the collision partners.

  13. Dynamics of plasma ions motion in ultra-intense laser-excited plasma wakes

    International Nuclear Information System (INIS)

    Zhou Suyun; Li Jing

    2013-01-01

    The effects of heavy ions and protons motion in an ultra-intense laser-driven plasma wake are compared by rebuilding a plasma wake model. It is shown that with the same laser and plasma background electron density n 0 , the heavy ions' motion suppresses wake-field resonant excitation less than the protons' motion in their own plasma wake. Though heavy ions obtain more kinetic energy from the plasma wake, its energy density is less than that of the protons due to the ion density being far less than the proton density. As a result, the total energy of heavy ions obtained from the wake-field is far less than that of protons. The dependence of the kinetic energy and the energy density of protons and heavy ions on n 0 is discussed. (paper)

  14. Effect of Coulomb collision on the negative ion extraction mechanism in negative ion sources.

    Science.gov (United States)

    Goto, I; Miyamoto, K; Nishioka, S; Mattei, S; Lettry, J; Abe, S; Hatayama, A

    2016-02-01

    To improve the H(-) ion beam optics, it is necessary to understand the energy relaxation process of surface produced H(-) ions in the extraction region of Cs seeded H(-) ion sources. Coulomb collisions of charged particles have been introduced to the 2D3V-PIC (two dimension in real space and three dimension in velocity space particle-in-cell) model for the H(-) extraction by using the binary collision model. Due to Coulomb collision, the lower energy part of the ion energy distribution function of H(-) ions has been greatly increased. The mean kinetic energy of the surface produced H(-) ions has been reduced to 0.65 eV from 1.5 eV. It has been suggested that the beam optics of the extracted H(-) ion beam is strongly affected by the energy relaxation process due to Coulomb collision.

  15. Kinetic Studies For the Removal of UO22+ and Pb2+ Ions From Aqueous Solution Using Zirconia Composite Material

    International Nuclear Information System (INIS)

    Sharaf El-Deen, G.E.

    2008-01-01

    Zirconia composite material was chemically synthesized previously and prepared by applying the sol-gel polymeric route using MgO as a stabilizer. The prepared composite material was characterized using various techniques: x-ray fluorescence (XRF), scanning electron microscope (SEM), differential thermal analysis and thermogravimetric analysis (DTA-TG), x-ray diffraction (XRD) and surface area using the BET-method. The sorption removal of UO 2 2+ and Pb 2+ ions from aqueous waste solution by zirconia composite material using batch technique was investigated. The sorption was carried out as a function of ph, particle size, shaking time and temperature. In this work, a comparison of kinetic models applied to the sorption process of each ion was evaluated for the pseudo first-order, the pseudo second-order, intra particle diffusion and homogeneous particle diffusion kinetic models, respectively. The results showed that the homogeneous particle diffusion model (HPDM) best correlate the experimental rate data and the numerical values of the rate constants and particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy (Ε a ) and thermodynamic parameters of free energy (δ G * ), enthalpy (δ H * ) and entropy (δ S * ) of activation were also computed from the linearized form of Arrhenius equation

  16. Kinetics of Cu (II) separation by ion flotation techniques, in cells with flexible spargers

    International Nuclear Information System (INIS)

    Reyes, M.; Tavera, F. J.; Escudero, R.; Patino, F.; Salinas, E.; Rivera, I.

    2010-01-01

    This research studies and experimentally determines the kinetic parameters and effect of modifying the hydrodynamics and chemical conditions of the air-liquid dispersions during the Cu (II) extraction by ion flotation techniques in cells with porous spargers. Results show that the elimination of Cu (II) from solution can be carried out by ion flotation in one stage, obtaining efficiencies of 68% and 56% for the flat and cylindrical sparger respectively with a xanthate concentration of 0,02 g/l. In multistage systems five cells, recoveries over 92 % were achieved for both sparger geometries. The behavior of the flotation apparent kinetic constant is linear to the parameters that characterize dispersion (Jg, eg y Db), until a point is achieved where the process instability makes the system inoperable. The results show that removing base metal ions by ion flotation is strongly affected by the following factors: collector concentration [C], Jg, eg, Db, Jl and Sb. (Author) 20 refs

  17. Contributions to the study of positive ion kinetics in gases

    International Nuclear Information System (INIS)

    Popescu, A.

    1978-01-01

    Extensive studies on cesium ion kinetics in cesium and cesium-noble gas mixtures were performed. The obtained data are correlated with the measured parameters of the thermionic diodes. The mobility of atomic and molecular cesium ions at low electric fields, including zero electric field, in cesium and cesium krypton mixtures were measured using the time of flight method and a special thermionic ion detector. The atomic ion conversion into molecular ions is theoretically considered in the diffusion equation of the charged particles and the obtained analytical relation is in good agreement with the experimental cesium measured data. The reaction rate of the ion conversion in cesium is considered from these measurements. Measurements on the diffused plasma through the anode (provided with holes) of the cesium thermionic diode supply data on the anode sheath, the ratio of electronic and ionic current, electron temperature and the nature of the cesium ions (atomic or molecular) for various modes of the low voltage arc discharge. The obtained data have been used for the optimization of the thermionic diode parameters, as well as for the development of a new type of device for the detection of impurities in the air. (author)

  18. Biosorption of lead ions on biosorbent prepared from plumb shells (spondias mombin): kinetics and equilibrium studies

    International Nuclear Information System (INIS)

    Adeogen, A.I.; Bello, O.S.; Adeboye, M.D.

    2010-01-01

    Plumb shell was used to prepare an adsorbent for biosorption of lead ions in aqueous solution at 25 degree C. The adsorption capacity of the adsorbent at equilibrium was found to increase from 2.8 to 49.0 mg/g with an increase in the initial lead ion concentration from 50 to 200 mg/L. Using the equilibrium and kinetics studies, isotherm of the lead ions on the biosorbent was determined and correlated with common isotherm equations. The equilibrium data for lead ion adsorption fitted well into the Freundlich equation, with a value of 0.76 (R2 = 0.9), with distribution coefficient of 4.90. The biosorption of lead ions on the adsorbent from plumb shells could best be described by the pseudo-second-order equation. The kinetic parameters of this best-fit model were calculated and discussed. (author)

  19. Doping of two-dimensional MoS2 by high energy ion implantation

    Science.gov (United States)

    Xu, Kang; Zhao, Yuda; Lin, Ziyuan; Long, Yan; Wang, Yi; Chan, Mansun; Chai, Yang

    2017-12-01

    Two-dimensional (2D) materials have been demonstrated to be promising candidates for next generation electronic circuits. Analogues to conventional Si-based semiconductors, p- and n-doping of 2D materials are essential for building complementary circuits. Controllable and effective doping strategies require large tunability of the doping level and negligible structural damage to ultrathin 2D materials. In this work, we demonstrate a doping method utilizing a conventional high-energy ion-implantation machine. Before the implantation, a Polymethylmethacrylate (PMMA) protective layer is used to decelerate the dopant ions and minimize the structural damage to MoS2, thus aggregating the dopants inside MoS2 flakes. By optimizing the implantation energy and fluence, phosphorus dopants are incorporated into MoS2 flakes. Our Raman and high-resolution transmission electron microscopy (HRTEM) results show that only negligibly structural damage is introduced to the MoS2 lattice during the implantation. P-doping effect by the incorporation of p+ is demonstrated by Photoluminescence (PL) and electrical characterizations. Thin PMMA protection layer leads to large kinetic damage but also a more significant doping effect. Also, MoS2 with large thickness shows less kinetic damage. This doping method makes use of existing infrastructures in the semiconductor industry and can be extended to other 2D materials and dopant species as well.

  20. Energy transfer mechanism between Ce and Tb ions in sol–gel synthesized YSO crystals

    International Nuclear Information System (INIS)

    Chiriu, Daniele; Stagi, Luigi; Carbonaro, Carlo Maria; Corpino, Riccardo; Ricci, Pier Carlo

    2016-01-01

    The luminescence properties of Tb and Ce in Rare Earth Doped crystalline oxides largely depend on their relative concentrations: by increasing the dopant concentration, the luminescence profile changes from blue to green because of the energy transfer among centers. The kinetic properties of the luminescence of optically excited Terbium–Cerium co-doped Y_2SiO_5 sol–gel synthesized crystal powders have been investigated as a function of the Tb dopant concentration (Ce content fixed at 1% atomic). The interaction among different Tb emitting centers and their relation with Ce centers was explained within the Inokuti-Hirayama model for a dipole–dipole energy transfer mechanism in the low-middle Tb concentration range whilst the Forster–Dexter model was applied in the middle-high Tb concentration range. The kinetic model allows elucidating the role of sensitizer and activator ion as a function of Tb concentration, successfully estimating the energy transfer mechanism efficiency and calculating the critical Tb concentration. - Highlights: • The kinetic properties of Ce, Tb recombination in YSO matrix were studied. • The Inokuti-Hirayama and Forster–Dexter models were applied. • At high Tb content, the Ce to Tb energy transfer acts through the dipole−quadrupole. • At low Tb content, the Ce to Tb energy transfer acts through the dipole−dipole. • The presence of Ce reduces the critical Tb concentration (at low Tb content).

  1. Energy transfer mechanism between Ce and Tb ions in sol–gel synthesized YSO crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chiriu, Daniele; Stagi, Luigi; Carbonaro, Carlo Maria; Corpino, Riccardo; Ricci, Pier Carlo, E-mail: carlo.ricci@dsf.unica.it

    2016-03-01

    The luminescence properties of Tb and Ce in Rare Earth Doped crystalline oxides largely depend on their relative concentrations: by increasing the dopant concentration, the luminescence profile changes from blue to green because of the energy transfer among centers. The kinetic properties of the luminescence of optically excited Terbium–Cerium co-doped Y{sub 2}SiO{sub 5} sol–gel synthesized crystal powders have been investigated as a function of the Tb dopant concentration (Ce content fixed at 1% atomic). The interaction among different Tb emitting centers and their relation with Ce centers was explained within the Inokuti-Hirayama model for a dipole–dipole energy transfer mechanism in the low-middle Tb concentration range whilst the Forster–Dexter model was applied in the middle-high Tb concentration range. The kinetic model allows elucidating the role of sensitizer and activator ion as a function of Tb concentration, successfully estimating the energy transfer mechanism efficiency and calculating the critical Tb concentration. - Highlights: • The kinetic properties of Ce, Tb recombination in YSO matrix were studied. • The Inokuti-Hirayama and Forster–Dexter models were applied. • At high Tb content, the Ce to Tb energy transfer acts through the dipole−quadrupole. • At low Tb content, the Ce to Tb energy transfer acts through the dipole−dipole. • The presence of Ce reduces the critical Tb concentration (at low Tb content).

  2. Kinetic-energy functionals studied by surface calculations

    DEFF Research Database (Denmark)

    Vitos, Levente; Skriver, Hans Lomholt; Kollár, J.

    1998-01-01

    The self-consistent jellium model of metal surfaces is used to study the accuracy of a number of semilocal kinetic-energy functionals for independent particles. It is shown that the poor accuracy exhibited by the gradient expansion approximation and most of the semiempirical functionals in the lo...... density, high gradient limit may be subtantially improved by including locally a von Weizsacker term. Based on this, we propose a simple one-parameter Pade's approximation, which reproduces the exact Kohn-Sham surface kinetic energy over the entire range of metallic densities....

  3. Performance Limitations in High-Energy Ion Colliders

    CERN Document Server

    Fischer, Wolfram

    2005-01-01

    High-energy ion colliders (hadron colliders operating with species other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. However, the experiments also expect flexibility with frequent changes in the collision energy, lattice configuration, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams, attention must be paid to space charge, charge exchange, and intra-beam scattering effects. The latter leads to luminosity lifetimes of only a few hours for heavy ions. Ultimately cooling at full energy is needed to overcome this effect. Currently, the Relativistic Heavy Ion Collider at BNL is the only operating high-energy ion collider. The Large Hadron Collider, under construction at CERN, will also run with heavy ions.

  4. Comparative study on ion-isotopic exchange reaction kinetics by application of tracer technique

    International Nuclear Information System (INIS)

    Lokhande, R.S.; Singare, P.U.

    2007-01-01

    The radioactive isotopes 131 I and 82 Br were used to trace the ion-isotopic exchange reactions using industrial grade ion exchange resins Amberlite IRA-400. The experiments were performed to understand the effect of temperature and concentration of ionic solution on kinetics of exchange reactions. Both the exchange reactions were greatly influenced by rise in temperature, which result in higher percentage of ions exchanged. For bromide ion-isotopic exchange reactions, the calculated values of specific reaction rate/min -1 , and amount of ions exchanged/mmol were obtained higher than that for iodide ion-isotopic exchange reactions under identical experimental conditions. The observed variation in the results for two ion-isotopic exchange reactions was due to the difference in the ionic size of bromide and iodide ions. (orig.)

  5. Collisions of low-energy multicharged ions

    International Nuclear Information System (INIS)

    Phaneuf, R.A.; Crandall, D.H.

    1981-01-01

    Experimental measurements of cross sections for collisions of multiply charged ions with atoms at the lowest attainable collision energies are reported. Emphasis is on electron capture from hydrogen atoms by multiply charged ions at energies below 1 keV/amu. The principal effort is the development of a merged-ion-atom-beams apparatus for studies down to 1 eV/amu relative energy

  6. Kinetic modelling for zinc (II) ions biosorption onto Luffa cylindrica

    International Nuclear Information System (INIS)

    Oboh, I.; Aluyor, E.; Audu, T.

    2015-01-01

    The biosorption of Zinc (II) ions onto a biomaterial - Luffa cylindrica has been studied. This biomaterial was characterized by elemental analysis, surface area, pore size distribution, scanning electron microscopy, and the biomaterial before and after sorption, was characterized by Fourier Transform Infra Red (FTIR) spectrometer. The kinetic nonlinear models fitted were Pseudo-first order, Pseudo-second order and Intra-particle diffusion. A comparison of non-linear regression method in selecting the kinetic model was made. Four error functions, namely coefficient of determination (R 2 ), hybrid fractional error function (HYBRID), average relative error (ARE), and sum of the errors squared (ERRSQ), were used to predict the parameters of the kinetic models. The strength of this study is that a biomaterial with wide distribution particularly in the tropical world and which occurs as waste material could be put into effective utilization as a biosorbent to address a crucial environmental problem

  7. Measurements of low energy auroral ions

    International Nuclear Information System (INIS)

    Urban, A.

    1981-01-01

    This paper summarizes ion measurements in the energy range 0.1 to 30 keV observed during the campaigns 'Substorm Phenomena' and 'Porcupine'. For a clear survey of the physical processes during extraordinary events, sometimes ion measurements of higher energies are also taken into account. Generally, the pitch angle distributions were isotropic during all flights except some remarkable events. In general the ion and electron flux intensities correlated, but sometimes revealed a spectral anti-correlation. Acceleration of the ions by an electrostatic field aligned parallel to the magnetic field could be identified accompanied by intense electron precipitation. On the other hand deceleration of the ions was observed in other field-aligned current sheets which are indicated by the electron and magnetic field measurements. Temporal successive monoenergetic ion variations pointed to energy dispersion and to the location of the source region at 9 Rsub(E). Furthermore, ion fluxes higher than those of the electrons were measured at pitch angles parallel to the magnetic field. The integral down-going number and energy flux of the ions contributed to the total particle or energy influx between 65% and less than 7% and did not clearly characterize the geophysical launch conditions or auroral activities. (author)

  8. Defect diffusion during annealing of low-energy ion-implanted silicon

    International Nuclear Information System (INIS)

    Bedrossian, P.J.; Caturla, M.J.; Diaz de la Rubia, T.

    1997-01-01

    The authors present a new approach for investigating the kinetics of defect migration during annealing of low-energy, ion-implanted silicon, employing a combination of computer simulations and atomic-resolution tunneling microscopy. Using atomically-clean Si(111)-7 x 7 as a sink for bulk point defects created by 5 keV Xe and Ar irradiation, they observe distinct, temperature-dependent surface arrival rates for vacancies and interstitials. A combination of simulation tools provides a detailed description of the processes that underlie the observed temperature-dependence of defect segregation, and the predictions of the simulations agree closely with the experimental observations

  9. Determination of metal-hydrogen bond dissociation energies by the deprotonation of transition metal hydride ions: application to MnH +

    Science.gov (United States)

    Stevens, Amy E.; Beauchamp, J. L.

    1981-03-01

    ICR trapped ion techniques are used to examine the kinetics of proton transfer from MnH + (formed as a fragment ion from HMn (CO) 5 by electron impact) to bases of varying strength. Deprotonation is rapid with bases whose proton affinity exceeds 196±3 kcal mol -1. This value for PA (Mn) yields the homolytic bond dissociation energy D0(Mn +-H) = 53±5 kcal mol -1.

  10. Bulk properties of the medium produced in relativistic heavy-ion collisions from the beam energy scan program

    Science.gov (United States)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, B.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Y.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, H.; Liu, P.; Liu, Y.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

    2017-10-01

    We present measurements of bulk properties of the matter produced in Au+Au collisions at √{sN N}=7.7 ,11.5 ,19.6 ,27 , and 39 GeV using identified hadrons (π±, K±, p , and p ¯) from the STAR experiment in the Beam Energy Scan (BES) Program at the Relativistic Heavy Ion Collider (RHIC). Midrapidity (|y |<0.1 ) results for multiplicity densities d N /d y , average transverse momenta 〈pT〉 , and particle ratios are presented. The chemical and kinetic freeze-out dynamics at these energies are discussed and presented as a function of collision centrality and energy. These results constitute the systematic measurements of bulk properties of matter formed in heavy-ion collisions over a broad range of energy (or baryon chemical potential) at RHIC.

  11. Effects of heavy ion temperature on low-frequency kinetic Alfven waves

    International Nuclear Information System (INIS)

    Yang, L.; Wu, D. J.

    2011-01-01

    Heavy ion-electron (or proton) temperature ratio varies in a wide range in the solar and space environment. In this paper, proton and heavy ion temperatures are included in a three-fluid plasma model. For the specified parameters, low-frequency (<< heavy ion gyrofrequency) kinetic Alfven waves (KAWs) with sub- and super-Alfvenic speeds are found to coexist in the same plasma environment. Our results show that the temperature ratio of heavy ions to electrons can considerably affect the dispersion, propagation, and electromagnetic polarizations of the KAWs. In particular, the temperature ratio can increase the ratio of parallel to perpendicular electric fields and the normalized electric to magnetic field ratio, the variations of which are greatly different in regions with a high heavy ion temperature and with a low one. The results may help to understand the physical mechanism of some energization processes of heavy ions in the solar and space plasma environment. Effects of the ratio of electron thermal to Alfven speeds and the heavy ion abundance on these parameters are also discussed.

  12. Studies of equilibrium and kinetics of adsorption of cesium ions by graphene oxide

    International Nuclear Information System (INIS)

    Oliveira, Fernando M.; Bueno, Vanessa N.; Oshiro, Maurício T.; Potiens Junior, Ademar J.; Hiromoto, Goro; Sakata, Solange K.; Rodrigues, Debora F.

    2017-01-01

    Cesium is one of the fission products of major radiological concern, it is often found in nuclear radioactive waste generated at nuclear power plants. Graphene Oxide (GO) has attracted great attention due to its functionalized surface, which includes hydroxyl, epoxy, carbonyl and carboxyl groups, with great capacity of complexation with metal ions and can be used as adsorbent to remove cations from aqueous solutions. In this work, a treatment of radioactive waste containing 137 Cs was studied. For the batch experiments of Cs + removal, 133 Cs concentrations remained after the adsorption were determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and the results obtained were analyzed according to the Langmuir and Freundlich isotherms models. The kinetics of adsorption and Gibbs free energy were also determined. The Langmuir model was the best fit and defined a favorable adsorption. The cesium adsorption process is the pseudo-second model and the Gibbs free energy calculation indicated that the adsorption process is spontaneous. (author)

  13. Studies of equilibrium and kinetics of adsorption of cesium ions by graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Fernando M.; Bueno, Vanessa N.; Oshiro, Maurício T.; Potiens Junior, Ademar J.; Hiromoto, Goro; Sakata, Solange K., E-mail: fmoliveira@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Rodrigues, Debora F., E-mail: dfrigiro@central.uh.edu [Department of Civil and Environmental Engineering, University of Houston, TX (United States)

    2017-07-01

    Cesium is one of the fission products of major radiological concern, it is often found in nuclear radioactive waste generated at nuclear power plants. Graphene Oxide (GO) has attracted great attention due to its functionalized surface, which includes hydroxyl, epoxy, carbonyl and carboxyl groups, with great capacity of complexation with metal ions and can be used as adsorbent to remove cations from aqueous solutions. In this work, a treatment of radioactive waste containing {sup 137}Cs was studied. For the batch experiments of Cs{sup +} removal, {sup 133}Cs concentrations remained after the adsorption were determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and the results obtained were analyzed according to the Langmuir and Freundlich isotherms models. The kinetics of adsorption and Gibbs free energy were also determined. The Langmuir model was the best fit and defined a favorable adsorption. The cesium adsorption process is the pseudo-second model and the Gibbs free energy calculation indicated that the adsorption process is spontaneous. (author)

  14. A Simple Analytical Model for Predicting the Detectable Ion Current in Ion Mobility Spectrometry Using Corona Discharge Ionization Sources

    Science.gov (United States)

    Kirk, Ansgar Thomas; Kobelt, Tim; Spehlbrink, Hauke; Zimmermann, Stefan

    2018-05-01

    Corona discharge ionization sources are often used in ion mobility spectrometers (IMS) when a non-radioactive ion source with high ion currents is required. Typically, the corona discharge is followed by a reaction region where analyte ions are formed from the reactant ions. In this work, we present a simple yet sufficiently accurate model for predicting the ion current available at the end of this reaction region when operating at reduced pressure as in High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) or most IMS-MS instruments. It yields excellent qualitative agreement with measurement results and is even able to calculate the ion current within an error of 15%. Additional interesting findings of this model are the ion current at the end of the reaction region being independent from the ion current generated by the corona discharge and the ion current in High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) growing quadratically when scaling down the length of the reaction region. [Figure not available: see fulltext.

  15. Kinetic energy definition in velocity Verlet integration for accurate pressure evaluation

    Science.gov (United States)

    Jung, Jaewoon; Kobayashi, Chigusa; Sugita, Yuji

    2018-04-01

    In molecular dynamics (MD) simulations, a proper definition of kinetic energy is essential for controlling pressure as well as temperature in the isothermal-isobaric condition. The virial theorem provides an equation that connects the average kinetic energy with the product of particle coordinate and force. In this paper, we show that the theorem is satisfied in MD simulations with a larger time step and holonomic constraints of bonds, only when a proper definition of kinetic energy is used. We provide a novel definition of kinetic energy, which is calculated from velocities at the half-time steps (t - Δt/2 and t + Δt/2) in the velocity Verlet integration method. MD simulations of a 1,2-dispalmitoyl-sn-phosphatidylcholine (DPPC) lipid bilayer and a water box using the kinetic energy definition could reproduce the physical properties in the isothermal-isobaric condition properly. We also develop a multiple time step (MTS) integration scheme with the kinetic energy definition. MD simulations with the MTS integration for the DPPC and water box systems provided the same quantities as the velocity Verlet integration method, even when the thermostat and barostat are updated less frequently.

  16. Kinetic energy definition in velocity Verlet integration for accurate pressure evaluation.

    Science.gov (United States)

    Jung, Jaewoon; Kobayashi, Chigusa; Sugita, Yuji

    2018-04-28

    In molecular dynamics (MD) simulations, a proper definition of kinetic energy is essential for controlling pressure as well as temperature in the isothermal-isobaric condition. The virial theorem provides an equation that connects the average kinetic energy with the product of particle coordinate and force. In this paper, we show that the theorem is satisfied in MD simulations with a larger time step and holonomic constraints of bonds, only when a proper definition of kinetic energy is used. We provide a novel definition of kinetic energy, which is calculated from velocities at the half-time steps (t - Δt/2 and t + Δt/2) in the velocity Verlet integration method. MD simulations of a 1,2-dispalmitoyl-sn-phosphatidylcholine (DPPC) lipid bilayer and a water box using the kinetic energy definition could reproduce the physical properties in the isothermal-isobaric condition properly. We also develop a multiple time step (MTS) integration scheme with the kinetic energy definition. MD simulations with the MTS integration for the DPPC and water box systems provided the same quantities as the velocity Verlet integration method, even when the thermostat and barostat are updated less frequently.

  17. Effect of Porosity on the Thick Electrodes for High Energy Density Lithium Ion Batteries for Stationary Applications

    Directory of Open Access Journals (Sweden)

    Madhav Singh

    2016-11-01

    Full Text Available A series of 250–350 μ m-thick single-sided lithium ion cell graphite anodes and lithium nickel manganese cobalt oxide (NMC cathodes with constant area weight, but varying porosity were prepared. Over this wide thickness range, micron-sized carbon fibers were used to stabilize the electrode structure and to improve electrode kinetics. By choosing the proper porosities for the anode and cathode, kinetic limitations and aging losses during cell cycling could be minimized and energy density improved. The cell (C38%-A48% exhibits the highest energy density, 441 Wh/L at the C/10 rate, upon cycling at elevated temperature and different C-rates. The cell (C38%-A48% showed 9% higher gravimetric energy density at C/10 in comparison to the cell with as-coated electrodes.

  18. Final Report: Mechanisms of sputter ripple formation: coupling among energetic ions, surface kinetics, stress and composition

    Energy Technology Data Exchange (ETDEWEB)

    Chason, Eric; Shenoy, Vivek

    2013-01-22

    Self-organized pattern formation enables the creation of nanoscale surface structures over large areas based on fundamental physical processes rather than an applied template. Low energy ion bombardment is one such method that induces the spontaneous formation of a wide variety of interesting morphological features (e.g., sputter ripples and/or quantum dots). This program focused on the processes controlling sputter ripple formation and the kinetics controlling the evolution of surfaces and nanostructures in high flux environments. This was done by using systematic, quantitative experiments to measure ripple formation under a variety of processing conditions coupled with modeling to interpret the results.

  19. An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

    Energy Technology Data Exchange (ETDEWEB)

    Thopan, P.; Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuldyuld@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells.

  20. An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

    International Nuclear Information System (INIS)

    Thopan, P.; Prakrajang, K.; Thongkumkoon, P.; Suwannakachorn, D.; Yu, L.D.

    2013-01-01

    Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells

  1. Alternative kinetic energy metrics for Lagrangian systems

    Science.gov (United States)

    Sarlet, W.; Prince, G.

    2010-11-01

    We examine Lagrangian systems on \\ {R}^n with standard kinetic energy terms for the possibility of additional, alternative Lagrangians with kinetic energy metrics different to the Euclidean one. Using the techniques of the inverse problem in the calculus of variations we find necessary and sufficient conditions for the existence of such Lagrangians. We illustrate the problem in two and three dimensions with quadratic and cubic potentials. As an aside we show that the well-known anomalous Lagrangians for the Coulomb problem can be removed by switching on a magnetic field, providing an appealing resolution of the ambiguous quantizations of the hydrogen atom.

  2. Kinetic electron emission from metal surfaces induced by impact of slow ions

    Czech Academy of Sciences Publication Activity Database

    Šroubek, Zdeněk; Lorinčík, Jan

    -, č. 625 (2014), s. 7-9 ISSN 0039-6028 R&D Projects: GA MŠk(CZ) ME10086 Institutional support: RVO:67985882 Keywords : Ion induced kinetic electron emission * Electronic excitation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.925, year: 2014

  3. Effect of Coulomb collision on the negative ion extraction mechanism in negative ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Goto, I., E-mail: goto@ppl.appi.keio.ac.jp; Nishioka, S.; Abe, S.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Mattei, S.; Lettry, J. [CERN, 1211 Geneva 23 (Switzerland)

    2016-02-15

    To improve the H{sup −} ion beam optics, it is necessary to understand the energy relaxation process of surface produced H{sup −} ions in the extraction region of Cs seeded H{sup −} ion sources. Coulomb collisions of charged particles have been introduced to the 2D3V-PIC (two dimension in real space and three dimension in velocity space particle-in-cell) model for the H{sup −} extraction by using the binary collision model. Due to Coulomb collision, the lower energy part of the ion energy distribution function of H{sup −} ions has been greatly increased. The mean kinetic energy of the surface produced H{sup −} ions has been reduced to 0.65 eV from 1.5 eV. It has been suggested that the beam optics of the extracted H{sup −} ion beam is strongly affected by the energy relaxation process due to Coulomb collision.

  4. Kinetic energy principle and neoclassical toroidal torque in tokamaks

    International Nuclear Information System (INIS)

    Park, Jong-Kyu

    2011-01-01

    It is shown that when tokamaks are perturbed, the kinetic energy principle is closely related to the neoclassical toroidal torque by the action invariance of particles. Especially when tokamaks are perturbed from scalar pressure equilibria, the imaginary part of the potential energy in the kinetic energy principle is equivalent to the toroidal torque by the neoclassical toroidal viscosity. A unified description therefore should be made for both physics. It is also shown in this case that the potential energy operator can be self-adjoint and thus the stability calculation can be simplified by minimizing the potential energy.

  5. Energy transfer and kinetics in mechanochemistry.

    Science.gov (United States)

    Chen, Zhiliang; Lu, Shengyong; Mao, Qiongjing; Buekens, Alfons; Wang, Yuting; Yan, Jianhua

    2017-11-01

    Mechanochemistry (MC) exerts extraordinary degradation and decomposition effects on many chlorinated, brominated, and even fluorinated persistent organic pollutants (POPs). However, its application is still limited by inadequate study of its reaction kinetic aspects. In the present work, the ball motion and energy transfer in planetary ball mill are investigated in some detail. Almost all milling parameters are summarised in a single factor-total effective impact energy. Furthermore, the MC kinetic between calcium oxide/Al and hexachlorobenzene is well established and modelled. The results indicate that total effective impact energy and reagent ratio are the two factors sufficient for describing the MC degradation degree of POPs. The reaction rate constant only depends on the chemical properties of reactants, so it could be used as an important index to appraise the quality of MC additives. This model successfully predicts the reaction rate for different operating conditions, indicating that it could be suitably applied for conducting MC reactions in other reactors.

  6. Kinetic energy management in road traffic injury prevention: a call for action

    Directory of Open Access Journals (Sweden)

    Davoud Khorasani-Zavareh

    2015-01-01

    Full Text Available Abstract: By virtue of their variability, mass and speed have important roles in transferring energies during a crash incidence (kinetic energy. The sum of kinetic energy is important in determining an injury severity and that is equal to one half of the vehicle mass multiplied by the square of the vehicle speed. To meet the Vision Zero policy (a traffic safety policy prevention activities should be focused on vehicle speed management. Understanding the role of kinetic energy will help to develop measures to reduce the generation, distribution, and effects of this energy during a road traffic crash. Road traffic injury preventive activities necessitate Kinetic energy management to improve road user safety.

  7. High Time-Resolved Kinetic Temperatures of Solar Wind Minor Ions Measured with SOHO/CELIAS/CTOF

    Science.gov (United States)

    Janitzek, N. P.; Berger, L.; Drews, C.; Wimmer-Schweingruber, R. F.

    2017-12-01

    Solar wind heavy ions with an atomic number Z > 2 are referred to as minor ions since they represent a fraction of less than one percent of all solar wind ions. They can be therefore regarded as test particles, only reacting to but not driving the dynamics of the solar wind plasma, which makes them a unique diagnostic tool for plasma wave phenomena both in the solar atmosphere and the extended heliosphere. In the past, several studies have investigated the kinetic temperatures of minor ions, but due to low counting statistics these studies are based on ion velocity distribution functions (VDFs) recorded over time periods of several hours. The Charge Time-Of-Flight (CTOF) mass spectrometer as part of the Charge, ELement and Isotope Analysis System (CELIAS) onboard the SOlar and Heliospheric Observatory (SOHO) provides solar wind heavy ion 1D radial VDFs with excellent charge state separation, an unprecedented cadence of 5 minutes and very high counting statistics, exceeding similar state-of-the-art instruments by a factor of ten. In our study, based on CTOF measurements at Langrangian point L1 between DOY 150 and DOY 220 in 1996, we investigate systematically the influence of the VDF time resolution on the derived kinetic temperatures for solar wind silicon and iron ions. The selected ion set spans a wide range of mass-per-charge from 3 amu/e heavy ions with ion-cyclotron waves.

  8. Mass spectrometric study of the negative and positive secondary ions emitted from ethanol microdroplets by MeV-energy heavy ion impact

    Science.gov (United States)

    Kitajima, Kensei; Majima, Takuya; Nishio, Tatsuya; Oonishi, Yoshiki; Mizutani, Shiori; Kohno, Jun-ya; Saito, Manabu; Tsuchida, Hidetsugu

    2018-06-01

    We have investigated the negative and positive secondary ions emitted from ethanol droplets by 4.0-MeV C3+ impact to reveal the characteristic features of the reaction processes induced by fast heavy ions at the liquid ethanol surface. Analysis of the secondary ions was performed by time-of-flight mass spectrometry for microdroplet targets in a high vacuum environment. Fragment ions, deprotonated cluster ions, and trace amounts of the reaction product ions are observed in the negative secondary ions. The main fragment anions are C2HmO- (m = 1, 3, and 5) and C2H- generated by loss of hydrogen and oxygen atoms. The reaction product anions include deprotonated glycols, larger alcohols, and their dehydrated and dehydrogenated forms generated by secondary reactions between fragments and radicals. Furthermore, C3Hm- (m = 0-2) and C4Hm- (m = 0 and 1) are observed, which could be produced through a plasma state generated in the heavy ion track. Deprotonated ethanol cluster ions, [(EtOH)n - H]-, are observed up to about n = 25. [(EtOH)n - H]- have smaller kinetic energies than the protonated cluster ions (EtOH)nH+. This probably represents the effect of the positive Coulomb potential transiently formed in the ion track. We also discuss the size distributions and structures of the water- and CH2OH-radical-attached ethanol cluster ions.

  9. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 1 covers papers on the advances of gas phase ion chemistry. The book discusses the advances in flow tubes and the measurement of ion-molecule rate coefficients and product distributions; the ion chemistry of the earth's atmosphere; and the classical ion-molecule collision theory. The text also describes statistical methods in reaction dynamics; the state selection by photoion-photoelectron coincidence; and the effects of temperature and pressure in the kinetics of ion-molecule reactions. The energy distribution in the unimolecular decomposition of ions, as well

  10. ENERGY DISSIPATION IN MAGNETIC NULL POINTS AT KINETIC SCALES

    International Nuclear Information System (INIS)

    Olshevsky, Vyacheslav; Lapenta, Giovanni; Divin, Andrey; Eriksson, Elin; Markidis, Stefano

    2015-01-01

    We use kinetic particle-in-cell and MHD simulations supported by an observational data set to investigate magnetic reconnection in clusters of null points in space plasma. The magnetic configuration under investigation is driven by fast adiabatic flux rope compression that dissipates almost half of the initial magnetic field energy. In this phase powerful currents are excited producing secondary instabilities, and the system is brought into a state of “intermittent turbulence” within a few ion gyro-periods. Reconnection events are distributed all over the simulation domain and energy dissipation is rather volume-filling. Numerous spiral null points interconnected via their spines form null lines embedded into magnetic flux ropes; null point pairs demonstrate the signatures of torsional spine reconnection. However, energy dissipation mainly happens in the shear layers formed by adjacent flux ropes with oppositely directed currents. In these regions radial null pairs are spontaneously emerging and vanishing, associated with electron streams and small-scale current sheets. The number of spiral nulls in the simulation outweighs the number of radial nulls by a factor of 5–10, in accordance with Cluster observations in the Earth's magnetosheath. Twisted magnetic fields with embedded spiral null points might indicate the regions of major energy dissipation for future space missions such as the Magnetospheric Multiscale Mission

  11. Surface structure modification of single crystal graphite after slow, highly charged ion irradiation

    Science.gov (United States)

    Alzaher, I.; Akcöltekin, S.; Ban-d'Etat, B.; Manil, B.; Dey, K. R.; Been, T.; Boduch, P.; Rothard, H.; Schleberger, M.; Lebius, H.

    2018-04-01

    Single crystal graphite was irradiated by slow, highly charged ions. The modification of the surface structure was studied by means of Low-Energy Electron Diffraction. The observed damage cross section increases with the potential energy, i.e. the charge state of the incident ion, at a constant kinetic energy. The potential energy is more efficient for the damage production than the kinetic energy by more than a factor of twenty. Comparison with earlier results hints to a strong link between early electron creation and later target atom rearrangement. With increasing ion fluence, the initially large-scale single crystal is first transformed into μ m-sized crystals, before complete amorphisation takes place.

  12. Renormalizing the kinetic energy operator in elementary quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Coutinho, F A B [Faculdade de Medicina, Universidade de Sao Paulo e LIM 01-HCFMUSP, 05405-000 Sao Paulo (Brazil); Amaku, M [Faculdade de Medicina Veterinaria e Zootecnia, Universidade de Sao Paulo, 05508-970 Sao Paulo (Brazil)], E-mail: coutinho@dim.fm.usp.br

    2009-09-15

    In this paper, we consider solutions to the three-dimensional Schroedinger equation of the form {psi}(r) = u(r)/r, where u(0) {ne} 0. The expectation value of the kinetic energy operator for such wavefunctions diverges. We show that it is possible to introduce a potential energy with an expectation value that also diverges, exactly cancelling the kinetic energy divergence. This renormalization procedure produces a self-adjoint Hamiltonian. We solve some problems with this new Hamiltonian to illustrate its usefulness.

  13. Renormalizing the kinetic energy operator in elementary quantum mechanics

    International Nuclear Information System (INIS)

    Coutinho, F A B; Amaku, M

    2009-01-01

    In this paper, we consider solutions to the three-dimensional Schroedinger equation of the form ψ(r) = u(r)/r, where u(0) ≠ 0. The expectation value of the kinetic energy operator for such wavefunctions diverges. We show that it is possible to introduce a potential energy with an expectation value that also diverges, exactly cancelling the kinetic energy divergence. This renormalization procedure produces a self-adjoint Hamiltonian. We solve some problems with this new Hamiltonian to illustrate its usefulness.

  14. Kinetic Properties of Solar Wind Silicon and Iron Ions

    Science.gov (United States)

    Janitzek, N. P.; Berger, L.; Drews, C.; Wimmer-Schweingruber, R. F.

    2017-12-01

    Heavy ions with atomic numbers Z>2 account for less than one percent of the solar wind ions. However, serving as test particles with differing mass and charge, they provide a unique experimental approach to major questions of solar and fundamental plasma physics such as coronal heating, the origin and acceleration of the solar wind and wave-particle interaction in magnetized plasma. Yet the low relative abundances of the heavy ions pose substantial challenges to the instrumentation measuring these species with reliable statistics and sufficient time resolution. As a consequence the numbers of independent measurements and studies are small. The Charge Time-Of-Flight (CTOF) mass spectrometer as part of the Charge, ELement and Isotope Analysis System (CELIAS) onboard the SOlar and Heliospheric Observatory (SOHO) is a linear time-of-flight mass spectrometer which was operated at Lagrangian point L1 in 1996 for a few months only, before it suffered an instrument failure. Despite its short operation time, the CTOF sensor measured solar wind heavy ions with excellent charge state separation, an unprecedented cadence of 5 minutes and very high counting statistics, exceeding similar state-of-the-art instruments by a factor of ten. In contrast to earlier CTOF studies which were based on reduced onboard post-processed data, in our current studies we use raw Pulse Height Analysis (PHA) data providing a significantly increased mass, mass-per-charge and velocity resolution. Focussing on silicon and iron ion measurements, we present an overview of our findings on (1) short time behavior of heavy ion 1D radial velocity distribution functions, (2) differential streaming between heavy ions and solar wind bulk protons, (3) kinetic temperatures of heavy ions. Finally, we compare the CTOF results with measurements of the Solar Wind Ion Composition Spectrometer (SWICS) instrument onboard the Advanced Composition Explorer (ACE).

  15. High-energy particle emission from galena and pyrite bombarded with Cs and O ions

    International Nuclear Information System (INIS)

    Karpuzov, D.S.; McIntyre, N.S.

    2002-01-01

    The ejection of energetic particles during steady-state ion surface bombardment has been investigated by means of a dynamic computer simulation as well as in a secondary ion mass spectrometry (SIMS)/low-energy ion scattering from surfaces (LEIS) experiment. The emphasis of this comparative study is on the mass dependence of high-energy tails in sputtering and backscattering for the bombardment of galena (PbS) and pyrite (FeS 2 ) with keV energy ion beam of cesium and oxygen. In the experiment, kinetic energy distributions of sputtered secondary ions (S + , Fe + , Pb + , S - ), as well as backscattered or re-sputtered primary ions (Cs + , O + , O - ), have been measured on a modified Cameca IMS-3f magnetic sector mass spectrometer for keV cesium (Cs + ) and oxygen (O 2 + , O - ) bombardment of galena and pyrite. Ejection of high-energy particles, with emission energies of up to ∼40% or up to ∼60% of the bombarding energy for sputtering of the lighter component (S ± ) with cesium or oxygen, respectively, and of up to ∼40% (Cs + ) and ∼80% (O ± ) for backscattering, has been observed for PbS. The computer simulations were based on the well-known MARLOWE code. In order to model the change of the stoichiometry of the binary compounds, dynamic modification of the target composition in the near-surface region was introduced. Cs incorporation was included, and a relative enrichment of the metallic component (Pb, Fe) in the top few layers due to preferential sputtering of sulfur was allowed. The computer simulations provide information on the formation of altered layer under sputter equilibrium as well as on the energy and angular emission distributions of sputtered and backscattered particles in steady-state conditions. Multiple scattering of Cs projectiles and dynamic re-sputtering of cesium that was previously incorporated in the altered near-surface region can be distinguished in the simulation, and matched with the experimental observations. In addition

  16. Electron loss from multiply protonated lysozyme ions in high energy collisions with molecular oxygen

    DEFF Research Database (Denmark)

    Hvelplund, P; Nielsen, SB; Sørensen, M

    2001-01-01

    We report on the electron loss from multiply protonated lysozyme ions Lys-Hn(n)+ (n = 7 - 17) and the concomitant formation of Lys-Hn(n+1)+. in high-energy collisions with molecular oxygen (laboratory kinetic energy = 50 x n keV). The cross section for electron loss increases with the charge state...... of the precursor from n = 7 to n = 11 and then remains constant when n increases further. The absolute size of the cross section ranges from 100 to 200 A2. The electron loss is modeled as an electron transfer process between lysozyme cations and molecular oxygen....

  17. Maximizing Ion Current by Space Charge Neutralization using Negative Ions and Dust Particles

    International Nuclear Information System (INIS)

    Smirnov, A.; Raitses, Y.; Fisch, N.J.

    2005-01-01

    Ion current extracted from an ion source (ion thruster) can be increased above the Child-Langmuir limit if the ion space charge is neutralized. Similarly, the limiting kinetic energy density of the plasma flow in a Hall thruster might be exceeded if additional mechanisms of space charge neutralization are introduced. Space charge neutralization with high-mass negative ions or negatively charged dust particles seems, in principle, promising for the development of a high current or high energy density source of positive light ions. Several space charge neutralization schemes that employ heavy negatively charged particles are considered. It is shown that the proposed neutralization schemes can lead, at best, only to a moderate but nonetheless possibly important increase of the ion current in the ion thruster and the thrust density in the Hall thruster

  18. Development of Li+ alumino-silicate ion source

    International Nuclear Information System (INIS)

    Roy, P.K.; Seidl, P.A.; Waldron, W.; Greenway, W.; Lidia, S.; Anders, A.; Kwan, J.

    2009-01-01

    To uniformly heat targets to electron-volt temperatures for the study of warm dense matter, one strategy is to deposit most of the ion energy at the peak of energy loss (dE/dx) with a low (E < 5 MeV) kinetic energy beam and a thin target. Lower mass ions have a peak dE/dx at a lower kinetic energy. To this end, a small lithium (Li+) alumino-silicate source has been fabricated, and its emission limit has been measured. These surface ionization sources are heated to 1000-1150 C where they preferentially emit singly ionized alkali ions. Alumino-silicates sources of K+ and Cs+ have been used extensively in beam experiments, but there are additional challenges for the preparation of high-quality Li+ sources: There are tighter tolerances in preparing and sintering the alumino-silicate to the substrate to produce an emitter that gives uniform ion emission, sufficient current density and low beam emittance. We report on recent measurements ofhigh ( up to 35 mA/cm2) current density from a Li+ source. Ion species identification of possible contaminants is being verified with a Wien (E x B) filter, and via time-of-flight.

  19. Li + solvation and kinetics of Li+–BF4-/PF 6 - ion pairs in ethylene carbonate. A molecular dynamics study with classical rate theories

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Tsun-Mei [Department of Chemistry, University of Wisconsin–Parkside, Kenosha, Wisconsin 53141, USA; Dang, Liem X. [Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 93352, USA

    2017-10-28

    Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ethylene carbonate (EC) exchange process between the first and second solvation shells around Li+ and the dissociation kinetics of ion pairs Li+-[BF4] and Li+-[PF6] in this solvent. We calculate the exchange rates using transition state theory and correct them with transmission coefficients computed by the reactive flux; Impey, Madden, and McDonald approaches; and Grote-Hynes theory. We found the residence times of EC around Li+ ions varied from 70 to 450 ps, depending on the correction method used. We found the relaxation times changed significantly from Li+-[BF4] to Li+-[PF6] ion pairs in EC. Our results also show that, in addition to affecting the free energy of dissociation in EC, the anion type also significantly influence the dissociation kinetics of ion pairing. This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. The calculations were carried out using computer resources provided by the Office of Basic Energy Sciences.

  20. Theoretical and numerical study of the expansion of a laser-produced plasma: high energy ion acceleration; Etude theorique et numerique de l'expansion d'un plasma cree par laser: acceleration d'ions a haute energie

    Energy Technology Data Exchange (ETDEWEB)

    Grismayer, T

    2006-12-15

    This work is a theoretical and numerical study on the high energy ion acceleration in laser created plasma expansion. The ion beams produced on the rear side of an irradiated foil reveal some characteristics (low divergence, wide spectra) which distinguish them from the ones coming from the front side. The discovery of these beams has renewed speculation for applications such as proton-therapy or proton radiography. The ion acceleration is performed via a self-consistent electrostatic field due to the charge separation between ions and hot electrons. In the first part of this dissertation, we present the fluid theoretical model and the hybrid code which simulates the plasma expansion. The numerical simulation of a recent experience on the dynamic of the electric field by proton radiography validates the theoretical model. The second part deals with the influence of an initial ion density gradient on the acceleration efficiency. We establish a model which relates the plasma dynamic and more precisely the wave breaking of the ion flow. The numerical results which predict a strong decrease of the ion maximum energy for large gradient length are in agreement with the experimental data. The Boltzmann equilibrium for the electron assumed in the first part has been thrown back into doubt in the third part. We adopt a kinetic description for the electron. The new version of the code can measure the Boltzmann law deviation which does not strongly modify the maximum energy that can reach the ions. (author)

  1. Kinetic energy absorbing pad

    International Nuclear Information System (INIS)

    Bricmont, R.J.; Hamilton, P.A.; Ming Long Ting, R.

    1981-01-01

    Reactors, fuel processing plants etc incorporate pipes and conduits for fluids under high pressure. Fractures, particularly adjacent to conduit elbows, produce a jet of liquid which whips the broken conduit at an extremely high velocity. An enormous impact load would be applied to any stationary object in the conduit's path. The design of cellular, corrugated metal impact pads to absorb the kinetic energy of the high velocity conduits is given. (U.K.)

  2. The ion population of the magnetotail during the 17 April 2002 magnetic storm: Large-scale kinetic simulations and IMAGE/HENA observations

    Science.gov (United States)

    Peroomian, Vahé; El-Alaoui, Mostafa; Brandt, Pontus C.:son

    2011-05-01

    The contribution of solar wind and ionospheric ions to the ion population of the magnetotail during the 17 April 2002 geomagnetic storm was investigated by using large-scale kinetic (LSK) particle tracing calculations. We began our investigation by carrying out a global magnetohydrodynamic simulation of the storm event by using upstream solar wind and interplanetary magnetic field data from the ACE spacecraft. We launched solar wind H+ ions and ionospheric O+ ions beginning at 0900 UT, ˜2 h prior to the sudden storm commencement (SSC), until 2000 UT. We found that during this Dst ˜ -98 nT storm, solar wind ions carried the bulk of the density and energy density in the nightside ring current and plasma sheet, with the notable exception of the 90 min immediately after the SSC when O+ densities in the ring current exceeded those of H+ ions. The LSK simulation did a very good job of reproducing ion densities observed by the Los Alamos National Laboratory spacecraft at geosynchronous orbit and reproduced the changes in the inner magnetosphere and the injection of ions observed by the IMAGE spacecraft during a substorm that occurred at 1900 UT. These comparisons with observations serve to validate our results throughout the magnetotail and allow us to obtain time-dependent maps of H+ and O+ density and energy density where IMAGE cannot make measurements. In essence, this work extends the viewing window of the IMAGE spacecraft far downtail.

  3. High-energy ion implantation of materials

    International Nuclear Information System (INIS)

    Williams, J.M.

    1991-11-01

    High-energy ion implantation is an extremely flexible type of surface treatment technique, in that it offers the possibility of treating almost any type of target material or product with ions of almost any chemical species, or combinations of chemical species. In addition, ion implantations can be combined with variations in temperature during or after ion implantation. As a result, the possibility of approaching a wide variety of surface-related materials science problems exists with ion implantation. This paper will outline factors pertinent to application of high-energy ion implantation to surface engineering problems. This factors include fundamental advantages and limitations, economic considerations, present and future equipment, and aspects of materials science

  4. Adsorption Kinetics of Cd(ll and Pb(ll Ions from Aqueous Solutions by Bamboo-Based Activated Charcoal and Bamboo Dust

    Directory of Open Access Journals (Sweden)

    Stevens Azubuike Odoemelam

    2015-01-01

    Full Text Available The use of bamboo dust (BD and bamboo-based activated charcoal for adsorption of Pb(ll and Cd(ll ions from aqueous solutions were assessed in this work. The effect of contact time on the uptake of these metal ions was studied in batch process. The adsorption data were correlated with pseudo first-order, pseudo second-order and diffusivity kinetic models. Results show that pseudo second-order kinetic model gave the best description for the adsorption process. Kinetic studies further showed that the adsorption transport mechanism was particle-diffusion controlled for the adsorption process. Results obtained generally showed that lead(ll ions were better adsorbed onto both adsorbents as compared to cadmium(ll. Comparison of sorption capacity for the two adsorbents shows that bamboo-based activated charcoal exhibited better removal for the metal ions than the bamboo dust.

  5. Thermal oxidative degradation kinetics of agricultural residues using distributed activation energy model and global kinetic model.

    Science.gov (United States)

    Ren, Xiu'e; Chen, Jianbiao; Li, Gang; Wang, Yanhong; Lang, Xuemei; Fan, Shuanshi

    2018-08-01

    The study concerned the thermal oxidative degradation kinetics of agricultural residues, peanut shell (PS) and sunflower shell (SS). The thermal behaviors were evaluated via thermogravimetric analysis and the kinetic parameters were determined by using distributed activation energy model (DAEM) and global kinetic model (GKM). Results showed that thermal oxidative decomposition of two samples processed in three zones; the ignition, burnout, and comprehensive combustibility between two agricultural residues were of great difference; and the combustion performance could be improved by boosting heating rate. The activation energy ranges calculated by the DAEM for the thermal oxidative degradation of PS and SS were 88.94-145.30 kJ mol -1 and 94.86-169.18 kJ mol -1 , respectively. The activation energy obtained by the GKM for the oxidative decomposition of hemicellulose and cellulose was obviously lower than that for the lignin oxidation at identical heating rate. To some degree, the determined kinetic parameters could acceptably simulate experimental data. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Prediction of free turbulent mixing using a turbulent kinetic energy method

    Science.gov (United States)

    Harsha, P. T.

    1973-01-01

    Free turbulent mixing of two-dimensional and axisymmetric one- and two-stream flows is analyzed by a relatively simple turbulent kinetic energy method. This method incorporates a linear relationship between the turbulent shear and the turbulent kinetic energy and an algebraic relationship for the length scale appearing in the turbulent kinetic energy equation. Good results are obtained for a wide variety of flows. The technique is shown to be especially applicable to flows with heat and mass transfer, for which nonunity Prandtl and Schmidt numbers may be assumed.

  7. Stabilization of kinetic internal kink mode by ion diamagnetic effects

    International Nuclear Information System (INIS)

    Naitou, H.; Kuramoto, T.; Kobayashi, T.; Yagi, M.; Tokuda, S.; Matsumoto, T.

    2000-04-01

    Ion diamagnetic effects on the m=1 (poloidal mode number) and n=1 (toroidal mode number) kinetic internal kink mode are studied numerically by the three-field gyro-reduced-MHD code in the cylindrical coordinates, GRM3F-CY. In the derivation of the gryo-reduced-MHD model including the ion diamagnetic effects, finite gyroradius effects of ions are added to the gyrokinetic Poisson equation (quasi-neutral condition) and the convection term of the conservation law of the ion density. It is found that the long wavelength approximation, ksub(perpendicular) ρ ti ti is the thermal ion gyroradius, fails to reproduce the correct dispersion relation; the formulation valid even for ksub(perpendicular) ρ ti >> 1 is necessary. The results of numerical calculation coincide with the theory for |ω *e |+|ω *i | 0 , where the growth rate reduces as the density gradient increases. Here ω *e and ω *i are electron and ion diamagnetic angular frequencies estimated at the rational surface of q=1 (q is a safety factor), respectively, and γ 0 is the growth rate for the uniform density. Very weak instability, however, is observed for |ω *e |+|ω *i | 0 , where the theory predicts the complete stabilization. This residual instability appears since the region with the density gradient is limited in the radial direction and the stabilization by the outgoing drift-wave like mode becomes incomplete. (author)

  8. Imperfect dark energy from kinetic gravity braiding

    Energy Technology Data Exchange (ETDEWEB)

    Deffayet, Cédric [AstroParticule and Cosmologie, UMR7164-CNRS, Université Denis Diderot-Paris 7, CEA, Observatoire de Paris, 10 rue Alice Domon et Léonie Duquet, F-75205 Paris Cedex 13 (France); Pujolàs, Oriol [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland); Sawicki, Ignacy; Vikman, Alexander, E-mail: deffayet@iap.fr, E-mail: oriol.pujolas@cern.ch, E-mail: ignacy.sawicki@nyu.edu, E-mail: alexander.vikman@nyu.edu [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

    2010-10-01

    We introduce a large class of scalar-tensor models with interactions containing the second derivatives of the scalar field but not leading to additional degrees of freedom. These models exhibit peculiar features, such as an essential mixing of scalar and tensor kinetic terms, which we have named kinetic braiding. This braiding causes the scalar stress tensor to deviate from the perfect-fluid form. Cosmology in these models possesses a rich phenomenology, even in the limit where the scalar is an exact Goldstone boson. Generically, there are attractor solutions where the scalar monitors the behaviour of external matter. Because of the kinetic braiding, the position of the attractor depends both on the form of the Lagrangian and on the external energy density. The late-time asymptotic of these cosmologies is a de Sitter state. The scalar can exhibit phantom behaviour and is able to cross the phantom divide with neither ghosts nor gradient instabilities. These features provide a new class of models for Dark Energy. As an example, we study in detail a simple one-parameter model. The possible observational signatures of this model include a sizeable Early Dark Energy and a specific equation of state evolving into the final de-Sitter state from a healthy phantom regime.

  9. Imperfect dark energy from kinetic gravity braiding

    International Nuclear Information System (INIS)

    Deffayet, Cédric; Pujolàs, Oriol; Sawicki, Ignacy; Vikman, Alexander

    2010-01-01

    We introduce a large class of scalar-tensor models with interactions containing the second derivatives of the scalar field but not leading to additional degrees of freedom. These models exhibit peculiar features, such as an essential mixing of scalar and tensor kinetic terms, which we have named kinetic braiding. This braiding causes the scalar stress tensor to deviate from the perfect-fluid form. Cosmology in these models possesses a rich phenomenology, even in the limit where the scalar is an exact Goldstone boson. Generically, there are attractor solutions where the scalar monitors the behaviour of external matter. Because of the kinetic braiding, the position of the attractor depends both on the form of the Lagrangian and on the external energy density. The late-time asymptotic of these cosmologies is a de Sitter state. The scalar can exhibit phantom behaviour and is able to cross the phantom divide with neither ghosts nor gradient instabilities. These features provide a new class of models for Dark Energy. As an example, we study in detail a simple one-parameter model. The possible observational signatures of this model include a sizeable Early Dark Energy and a specific equation of state evolving into the final de-Sitter state from a healthy phantom regime

  10. A self-consistent derivation of ion drag and Joule heating for atmospheric dynamics in the thermosphere

    Directory of Open Access Journals (Sweden)

    X. Zhu

    2005-11-01

    Full Text Available The thermosphere is subject to additional electric and magnetic forces, not important in the middle and lower atmosphere, due to its partially ionized atmosphere. The effects of charged particles on the neutral atmospheric dynamics are often parameterized by ion drag in the momentum equations and Joule heating in the energy equation. Presented in this paper are a set of more accurate parameterizations for the ion drag and Joule heating for the neutral atmosphere that are functions of the difference between bulk ion velocity and neutral wind. The parameterized expressions also depend on the magnetic field, the Pedersen and Hall conductivities, and the ratio of the ion cyclotron frequency to the ion-neutral collision frequency. The formal relationship between the electromagnetic energy, atmospheric kinetic energy, and Joule heating is illustrated through the conversion terms between these three types of energy. It is shown that there will always be an accompanying conversion of kinetic energy into Joule heating when electromagnetic energy is generated through the dynamo mechanism of the atmospheric neutral wind. Likewise, electromagnetic energy cannot be fully converted into kinetic energy without producing Joule heating in the thermosphere.

  11. Energy-dispersed ions in the plasma sheet boundary layer and associated phenomena: Ion heating, electron acceleration, Alfvén waves, broadband waves, perpendicular electric field spikes, and auroral emissions

    Directory of Open Access Journals (Sweden)

    A. Keiling

    2006-10-01

    Full Text Available Recent Cluster studies reported properties of multiple energy-dispersed ion structures in the plasma sheet boundary layer (PSBL that showed substructure with several well separated ion beamlets, covering energies from 3 keV up to 100 keV (Keiling et al., 2004a, b. Here we report observations from two PSBL crossings, which show a number of identified one-to-one correlations between this beamlet substructure and several plasma-field characteristics: (a bimodal ion conics (<1 keV, (b field-aligned electron flow (<1 keV, (c perpendicular electric field spikes (~20 mV/m, (d broadband electrostatic ELF wave packets (<12.5 Hz, and (e enhanced broadband electromagnetic waves (<4 kHz. The one-to-one correlations strongly suggest that these phenomena were energetically driven by the ion beamlets, also noting that the energy flux of the ion beamlets was 1–2 orders of magnitude larger than, for example, the energy flux of the ion outflow. In addition, several more loosely associated correspondences were observed within the extended region containing the beamlets: (f electrostatic waves (BEN (up to 4 kHz, (g traveling and standing ULF Alfvén waves, (h field-aligned currents (FAC, and (i auroral emissions on conjugate magnetic field lines. Possible generation scenarios for these phenomena are discussed. In conclusion, it is argued that the free energy of magnetotail ion beamlets drove a variety of phenomena and that the spatial fine structure of the beamlets dictated the locations of where some of these phenomena occurred. This emphasizes the notion that PSBL ion beams are important for magnetosphere-ionosphere coupling. However, it is also shown that the dissipation of electromagnetic energy flux (at altitudes below Cluster of the simultaneously occurring Alfvén waves and FAC was larger (FAC being the largest than the dissipation of beam kinetic energy flux, and thus these two energy carriers contributed more to the energy transport on PSBL field lines

  12. Mass-selective isolation of ions stored in a quadrupole ion trap. A simulation study

    Science.gov (United States)

    March, Raymond E.; Londry, Frank A.; Alfred, Roland L.; Franklin, Anthony M.; Todd, John F. J.

    1992-01-01

    Trajectories of single ions stored in the quadrupole ion trap have been calculated using a simulation program described as the specific program for quadrupolar resonance (SPQR). Previously, the program has been used for the investigation of quadrupolar resonance excitation of ions with a static working point (or co-ordinates) in the stability diagram. The program has been modified to accommodate continuous d.c. and/or r.f. voltage ramps so as to permit calculation of ion trajectories while the working point is being changed. The modified program has been applied to the calculation of ion trajectories during ion isolation, or mass-selective storage, in the ion trap. The quadrupolar resonance excitation aspect of SPQR was not used in this study. Trajectories are displayed as temporal variations of ion kinetic energy, and axial and radial excursions from the centre of the ion trap. The working points of three ion species (m/z 144, 146 and 148), located initially on the qz, axis with qz [approximate] 0.12, were moved to the vicinity of the upper apex by a combination of r.f. and d.c. voltages applied in succession. Stable trajectories were maintained only for the ion species of m/z 146 for which the working point lay within this apex; the other ion species were ejected either radially or axially. The d.c. voltage was then reduced to zero so as to restore the working point of the isolated ion species to the qz axis. The amplitude of the r.f voltage was reduced to its initial value so as to retrieve the initial working point for m/z 146. The process extended over a real time of 2.9 ms, and was collision-free. The trajectory of the isolated ion was stable during this process; the ion species with m/z value lower than that of the target ion, that is, m/z 144, was ejected axially at the [beta]z = 1 boundary, while that with higher m/z value, that is, m/z 148, was ejected radially at the [beta]r = 0 boundary, as expected. The moderating effects of buffer gas were not taken

  13. The Mean Excitation Energy of Atomic Ions

    DEFF Research Database (Denmark)

    Sauer, Stephan; Oddershede, Jens; Sabin, John R.

    2015-01-01

    A method for calculation of the mean excitation energies of atomic ions is presented, making the calculation of the energy deposition of fast ions to plasmas, warm, dense matter, and complex biological systems possible. Results are reported to all ions of helium, lithium, carbon, neon, aluminum...

  14. Preliminary scaling laws for plasma current, ion kinetic temperature, and plasma number density in the NASA Lewis bumpy torus plasma

    Science.gov (United States)

    Roth, J. R.

    1976-01-01

    Parametric variation of independent variables which may affect the characteristics of bumpy torus plasma have identified those which have a significant effect on the plasma current, ion kinetic temperature, and plasma number density, and those which do not. Empirical power law correlations of the plasma current, and the ion kinetic temperature and number density were obtained as functions of potential applied to the midplane electrode rings, the background neutral gas pressure, and the magnetic field strength. Additional parameters studied included the type of gas, the polarity of the midplane electrode rings, the mode of plasma operation, and the method of measuring the plasma number density. No significant departures from the scaling laws appear to occur at the highest ion kinetic temperatures or number densities obtained to date.

  15. Spectrophotometric Analysis of the Kinetic of Pd(II Chloride Complex Ions Sorption Process from Diluted Aqua Solutions Using Commercially Available Activated Carbon

    Directory of Open Access Journals (Sweden)

    Wojnicki M.

    2017-12-01

    Full Text Available In this paper, results of adsorption kinetic studies of Pd(II chloride complex ions on activated carbon Organosrob 10 CO are presented. Spectorphotometrical method was applied to investigate the process. Kinetic model was proposed, and fundamental thermodynamic parameters were determined. Proposed kinetic model describes well observed phenomenon in the studied range of concentration of Pd(II chloride complex ions as well, as concentration of activated carbon.

  16. Moderate energy ions for high energy density physics experiments

    International Nuclear Information System (INIS)

    Grisham, L.R.

    2004-01-01

    This paper gives the results of a preliminary exploration of whether moderate energy ions (≅0.3-3 MeV/amu) could be useful as modest-cost drivers for high energy density physics experiments. It is found that if the target thickness is chosen so that the ion beam enters and then leaves the target in the vicinity of the peak of the dE/dX (stopping power) curve, high uniformity of energy deposition may be achievable while also maximizing the amount of energy per beam particle deposited within the target

  17. Computer simulation of scattered ion and sputtered species effects in ion beam sputter-deposition of high temperature superconducting thin films

    International Nuclear Information System (INIS)

    Krauss, A.R.; Auciello, O.

    1992-01-01

    Ion beam sputter-deposition is a technique currently used by many groups to produce single and multicomponent thin films. This technique provides several advantages over other deposition methods, which include the capability for yielding higher film density, accurate stoichiometry control, and smooth surfaces. However, the relatively high kinetic energies associated with ion beam sputtering also lead to difficulties if the process is not properly controlled. Computer simulations have been performed to determine net deposition rates, as well as the secondary erosion, lattice damage, and gas implantation in the films, associated with primary ions scattered from elemental Y, Ba and Cu targets used to produce high temperature superconducting Y-Ba-Cu-O films. The simulations were performed using the TRIM code for different ion masses and kinetic energies, and different deposition geometries. Results are presented for primary beams of Ar + , Kr + and Xe + incident on Ba and Cu targets at 0 degrees and 45 degrees with respect to the surface normal, with the substrate positioned at 0 degrees and 45 degrees. The calculations indicate that the target composition, mass and kinetic energy of the primary beam, angle of incidence on the target, and position and orientation of the substrate affect the film damage and trapped primary beam gas by up to 5 orders of magnitude

  18. Determination of triacylglycerol regioisomers using electrospray ionization-quadrupole ion trap mass spectrometry with a kinetic method.

    Science.gov (United States)

    Leveque, Nathalie L; Acheampong, Akwasi; Heron, Sylvie; Tchapla, Alain

    2012-04-13

    The kinetic method was applied to differentiate and quantify mixtures of regioisomeric triacylglycerols (TAGs) by generating and mass selecting alkali ion bound metal dimeric clusters with a TAG chosen as reference (ref) and examining their competitive dissociations in a quadrupole ion trap mass spectrometer. This methodology readily distinguished pairs of regioisomers (AAB/ABA) such as LLO/LOL, OOP/OPO and SSP/SPS and consequently distinguished sn-1/sn-3, sn-2 substituents on the glycerol backbone. The dimeric complex ions [ref, Li, TAG((AAB and/or ABA))](+) generated by electrospray ionization mass spectrometry were subjected to collision induced dissociation causing competitive loss of either the neutral TAG reference (ref) leading to [Li(AAB and/or ABA)](+) or the neutral TAG molecule (TAG((AAB and/or ABA))) leading to [ref, Li](+). The ratio of the two competitive dissociation rates, defined by the product ion branching ratio (R(iso)), was related via the kinetic method to the regioisomeric composition of the investigated TAG mixture. In this work, a linear correlation was established between composition of the mixture of each TAG regioisomer and the logarithm of the branching ratio for competitive fragmentation. Depending on the availability of at least one TAG regioisomer as standard, the kinetic method and the standard additions method led to the quantitative analysis of natural TAG mixtures. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Ion Exchange Kinetics of some Heavy Metals from Aqueous Solutions onto Poly(Acrylic Acid-Acrylo nitrle) Potassium Titanate

    International Nuclear Information System (INIS)

    El-Shorbagy, M.M.; El-Sadek, A.A.

    2012-01-01

    Composite inorganic-organic absorbers represent a group of inorganic ion exchangers modified using binding organic materials for preparation of larger size particles heaving higher granular strength. Such modification of originally powdered or microcrystalline inorganic ion exchangers makes their application in peaked beds possible-modified polyacrylonitrile (PAN) has been used as a universal binding polymer for a number of inorganic ion exchangers. The kinetic of ion exchange and sorption capacity of such composite absorbers is not influenced by the binding polymer mentioned above. These composites have been tested for separation and concentration of various contaminants from aqueous solutions. Their high selectivity and sorption efficiency are advantageous for treatment of various industrial waste waters. Removal of natural or artificial and the heavy metals, Pb, Cd and Zn ions. the influence of initial metal ion concentration and ph on metal ion removal has been studied. The process was found to follow a first order rate kinetics. The intra-particle diffusion of ions through pores in the adsorbent was to be the main rate limiting step. The selectivity order towards the ions was Pb(II) > Cd(II) > Zn(II)

  20. Study of kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 4

    International Nuclear Information System (INIS)

    Stamberg, K.; Plicka, J.; Calibar, J.; Gosman, A.

    1985-01-01

    The kinetics of ion exchange in the Nasup(+)-Mgsup(2+)-strongly acidic cation exchanger system in a batch stirred reactor was studied. The samples of exchangers OSTION KS (containing DVB in the range of 1.5 - 12%) and AMBERLITE IR 120 for experimental work were used; the concentration of the aqueous nitrate solution was always 0.2M. The Nernst-Planck equation for description of diffusion of ions in a particle was used. The values of diffusion coefficients of magnesium ions in the exchangers and their dependence on the content of DVB were obtained by evaluating the experimental data and using the self-diffusion coefficients of sodium. (author)

  1. Measurement of ultra-low ion energy of decelerated ion beam using a deflecting electric field

    Energy Technology Data Exchange (ETDEWEB)

    Thopan, P.; Suwannakachorn, D.; Tippawan, U. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2015-12-15

    In investigation on ultra-low-energy ion bombardment effect on DNA, an ion beam deceleration lens was developed for high-quality ultra-low-energy ion beam. Measurement of the ion energy after deceleration was necessary to confirm the ion beam really decelerated as theoretically predicted. In contrast to conventional methods, this work used a simple deflecting electrostatic field after the deceleration lens to bend the ion beam. The beam bending distance depended on the ion energy and was described and simulated. A system for the measurement of the ion beam energy was constructed. It consisted of a pair of parallel electrode plates to generate the deflecting electrical field, a copper rod measurement piece to detect ion beam current, a vernier caliper to mark the beam position, a stepping motor to translate the measurement rod, and a webcam-camera to read the beam bending distance. The entire system was installed after the ion-beam deceleration lens inside the large chamber of the bioengineering vertical ion beam line. Moving the measurement rod across the decelerated ion beam enabled to obtain beam profiles, from which the beam bending distance could be known and the ion beam energy could be calculated. The measurement results were in good agreement with theoretical and simulated results.

  2. Ion-exchange Resin Catalyzed Esterification of Lactic Acid with Isopropanol: a Kinetic Study

    Directory of Open Access Journals (Sweden)

    Amrit P. Toor

    2011-05-01

    Full Text Available The kinetic behavior of esterification of lactic acid with isopropanol over an acidic cation exchange resin, Amberlyst 15, was studied under isothermal condition. Isopropyl lactate synthesized in this reaction is an important pharmaceutical intermediate. The experiments were carried out in a stirred batch reactor in the temperature range of 323.15 to 353.15 K. The effect of various parameters such as temperature, molar ratio and catalyst loading was studied. Variation in parameters on rate of reaction demonstrated that the reaction was intrinsically controlled. Kinetic modeling was performed using Eley-Rideal model which acceptably fits the experimental data. The activation energy was found to be 22.007 kJ/mol and frequency factor was 0.036809 l2 g-1 mol-1 min-1 for forward reaction. The value of entropy for the forward reaction was found to be 182.317 J K-1 mol-1 . © 2011 BCREC UNDIP. All rights reserved(Received: 19th January 2011, Revised: 16th March 2011; Accepted: 16th March 2011[How to Cite: A.P. Toor, M. Sharma, S. Thakur, and R. K. Wanchoo. (2011. Ion-exchange Resin Catalyzed Esterification of Lactic Acid with Isopropanol: a Kinetic Study. Bulletin of Chemical Reaction Engineering and Catalysis, 6(1: 39-45. doi:10.9767/bcrec.6.1.791.39-45][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.791.39-45 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/791 ] | View in  

  3. Tailored ion energy distributions on plasma electrodes

    International Nuclear Information System (INIS)

    Economou, Demetre J.

    2013-01-01

    As microelectronic device features continue to shrink approaching atomic dimensions, control of the ion energy distribution on the substrate during plasma etching and deposition becomes increasingly critical. The ion energy should be high enough to drive ion-assisted etching, but not too high to cause substrate damage or loss of selectivity. In many cases, a nearly monoenergetic ion energy distribution (IED) is desired to achieve highly selective etching. In this work, the author briefly reviews: (1) the fundamentals of development of the ion energy distribution in the sheath and (2) methods to control the IED on plasma electrodes. Such methods include the application of “tailored” voltage waveforms on an electrode in continuous wave plasmas, or the application of synchronous bias on a “boundary electrode” during a specified time window in the afterglow of pulsed plasmas

  4. Fragmentation and reactivity of energy-selected ferrocenium ions

    International Nuclear Information System (INIS)

    Mestdagh, H.; Dutuit, O.; Heninger, M.; Thissen, R.; Alcaraz, C.

    2002-01-01

    In this study, results concerning the discussion of state-selected ferrocenium ions (c-C 5 H 5 ) 2 Fe + commonly called Cp 2 Fe + , as well as their reactions with methanol and ethanol are presented. Parent ions Cp 2 Fe + were produced by vacuumultraviolett (VUV) photoionization of neutral ferrocene using synchrotron radiation, and selected in internal energy by threshold photoelectron-photoion coincidences. The apparatus is divided into three differentially pumped regions: the source, the reaction and the detection zones. In source, state-selected parent ions are formed and can be selected in mass by a first quadrupole filter. State-selected ions are then injected in the second zone which is a RF octopole ion guide where reaction product ions are mass analyzed by a second quadrupole filter and detected by microchannelplates. In addition, the long flight time in the octopoles (several hundreds of microseconds) allows studying long-lived metastable ions. Total mass spectra were recorded at different photon energies, in addition to the main CpFe + and Fe + fragments, several minor fragments were detected such as C 10 H 10 + which reflects the formation of a C-C bond between the two Cp ligands. Losses of CH 3 , C 2 H 2 and C-4H 4 also indicate that important structure rearrangements take place before cleavage. The appearance energies of each mass-selected fragment ion were measured by recording fragment ion yields as a function of photon energy. Surprisingly, all fragments were found to have the same energy onset, i.e. 13.2 eV photon energy, except for C 3 H 3 Fe + (m/z 95). For Fe + ions, a sharp increase was observed at 17 eV, above the thermochemical onset of Fe + + 2 Cp. The 13.2 eV appearance energy of Fe + is thus assigned to the formation of Fe - + C 10 H 10 . The reactivity of ferrocenium ion with methanol and ethanol was investigated as a function of photon energy. While no reaction occurs at lower photon energies, several reaction products appear at 13.0 e

  5. Adsorption kinetic parameters of Fe3+ and Ni2+ ions by gyrolite

    Directory of Open Access Journals (Sweden)

    Kestutis Baltakys

    2015-03-01

    Full Text Available In this work the adsorption kinetic parameters for Fe3+ and Ni2+ ions by gyrolite are presented. Additionally, the adsoption mechanism was described by using pseudo first order and pseudo second order  equations. It was determined that the adsorption capacity of gyrolite and intrusion of heavy metals ions in its structure depends on reaction time and the pH value of adsorptive. It was observed that the incorporation of Fe3+ ions occurs more intensive than Ni2+ ions. It was found that in the acidic solution the intrusion of Fe3+ ions into gyrolite structure proceeds by two types of chemical reaction mechanisms: substitution and addition. Meanwhile, nickel ions were participated only in substitution reaction: gyrolite-Ca0 + Mex+ ↔ gyrolite-Me0 + Ca2+. It was observed that the pseudo second order model fit well for iron and nickel ions adsorption mechanism. It was estimated that the adsorption reactions are not reversible process and the crystal structure of gyrolite is stable. Moreover, synthetic adsorbent and the products of sorption were characterized by XRD, STA and FT-IR methods.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5735

  6. Investigation of energy transfer in ion associates by the nanosecond multichannel analysis

    International Nuclear Information System (INIS)

    Ermolaev, V.L.; Kotlyar, I.P.; Turaeva, Z.N.; Shakhverdov, T.A.

    1980-01-01

    The one-photon counting method is used to study the kinetics of fluorescence attenuation of pyrenetetrasulfonate and eosin bound into associates with ions of rare-earth elements in dimethylsulfoxide. This attenuation is shown to be exponential for all cases. The disagreement is found between the values of quenching of associates fluorescence, which are detrmined from its quantum yield and the lifetime with full complexing of the ligand. The results obtained are interpreted based on the existence in the solution of two types of complexes (extraspherical and intraspherical)in equilibrium. Basis parameters of energy transfer in each complex are determined

  7. An electron cyclotron resonance ion source based low energy ion beam platform

    International Nuclear Information System (INIS)

    Sun, L. T.; Shang, Y.; Ma, B. H.; Zhang, X. Z.; Feng, Y. C.; Li, X. X.; Wang, H.; Guo, X. H.; Song, M. T.; Zhao, H. Y.; Zhang, Z. M.; Zhao, H. W.; Xie, D. Z.

    2008-01-01

    To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed

  8. An electron cyclotron resonance ion source based low energy ion beam platform.

    Science.gov (United States)

    Sun, L T; Shang, Y; Ma, B H; Zhang, X Z; Feng, Y C; Li, X X; Wang, H; Guo, X H; Song, M T; Zhao, H Y; Zhang, Z M; Zhao, H W; Xie, D Z

    2008-02-01

    To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed.

  9. Mean excitation energies for molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Phillip W.K.; Sauer, Stephan P.A. [Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Oddershede, Jens [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States); Sabin, John R., E-mail: sabin@qtp.ufl.edu [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States)

    2017-03-01

    The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state contributing to the mean excitation energy.

  10. Nanostructured energy devices equilibrium concepts and kinetics

    CERN Document Server

    Bisquert, Juan

    2014-01-01

    Due to the pressing needs of society, low cost materials for energy devices have experienced an outstanding development in recent times. In this highly multidisciplinary area, chemistry, material science, physics, and electrochemistry meet to develop new materials and devices that perform required energy conversion and storage processes with high efficiency, adequate capabilities for required applications, and low production cost. Nanostructured Energy Devices: Equilibrium Concepts and Kinetics introduces the main physicochemical principles that govern the operation of energy devices. It inclu

  11. Damage of copper by low energy xenon ions

    International Nuclear Information System (INIS)

    Babad-Zakhryapin, A.A.; Popenko, V.A.

    1988-01-01

    Changes in the copper crystal structure bombarded by xenon ions with 30-150 eV energy are studied. Foils of MOb copper mark, 10 mm in diameter and 100 μm thickness, are irradiated. The initial specimens are annealed in vacuum during 1 h at 900 K temperature. The specimens are bombarded by xenon ions in a water-cooled holder. A TE-O type accelerator serves as a xenon ion source. The ion energy varies within 30 to 150 eV range. The ion flux density is 8x10 16 ion/(cm 2 xs). It is shown that crystal structure variations at deep depths are observed not only at high (>1 keV), but at low ion energies down to several dozens of electronvolt as well. The crystal structure variation on copper irradiation by xenon ions with 30-150 eV energy is followed by formation of defects like dislocation loops, point defects in the irradiated target bulk

  12. Low energy ion beam dynamics of NANOGAN ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sarvesh, E-mail: sarvesh@iuac.res.in; Mandal, A.

    2016-04-01

    A new low energy ion beam facility (LEIBF) has been developed for providing the mass analyzed highly charged intense ion beams of energy ranging from a few tens of keV to a few MeV for atomic, molecular and materials sciences research. The new facility consists of an all permanent magnet 10 GHz electron cyclotron resonance (ECR) ion source (NANOGAN) installed on a high voltage platform (400 kV) which provides large currents of multiply charged ion beams. Higher emittance at low energy of intense ion beam puts a tremendous challenge to the beam optical design of this facility. The beam line consists of mainly the electrostatic quadrupoles, an accelerating section, analyzing cum switching magnet and suitable beam diagnostics including vacuum components. The accelerated ion beam is analyzed for a particular mass to charge (m/q) ratio as well as guided to three different lines along 75°, 90° and 105° using a large acceptance analyzing cum switching magnet. The details of transverse beam optics to all the beam lines with TRANSPORT and GICOSY beam optics codes are being described. Field computation code, OPERA 3D has been utilized to design the magnets and electrostatic quadrupoles. A theoretical estimation of emittance for optimized geometry of ion source is given so as to form the basis of beam optics calculations. The method of quadrupole scan of the beam is used to characterize the emittance of the final beam on the target. The measured beam emittance increases with m/q ratios of various ion beams similar to the trend observed theoretically.

  13. A two-dimensional kinetic model of the scrape-off layer

    International Nuclear Information System (INIS)

    Catto, P.J.; Hazeltine, R.D.

    1993-09-01

    A two-dimensional (radius and poloidal angle), analytically tractable kinetic model of the ion (or energetic electron) behavior in the scrape-off layer of a limiter or divertor plasma in a tokamak is presented. The model determines the boundary conditions on the core ion density and ion temperature gradients, the power load on the limiter or divertor plates, the energy carried per particle to the walls, and the effective flux limit. The self-consistent electrostatic potential in the quasi-neutral scrape-off layer is determined by using the ion kinetic model of the layer along with a Maxwell-Boltzmann electron response that occurs because most electrons are reflected by the Debye sheaths (assumed to be infinitely thin) at the limiter or divertor plates

  14. Ion Kinetics in the Solar Wind: Coupling Global Expansion to Local Microphysics

    Czech Academy of Sciences Publication Activity Database

    Matteini, L.; Hellinger, Petr; Landi, S.; Trávníček, Pavel M.; Velli, M.

    2012-01-01

    Roč. 172, 1-4 (2012), s. 373-396 ISSN 0038-6308 Grant - others:ESA(XE) PECS 98068; AVO(CZ) IAA300420702 Program:IA Institutional research plan: CEZ:AV0Z10030501; CEZ:AV0Z30420517 Keywords : solar wind * ion kinetics * numerical simulations Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.519, year: 2012

  15. Low energy ion-molecule reactions

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, J.M. [Univ. of Rochester, NY (United States)

    1993-12-01

    This project is concerned with elucidating the dynamics of elementary ion-molecule reactions at collision energies near and below 1 eV. From measurements of the angular and energy distributions of the reaction products, one can infer intimathe details about the nature of collisions leading to chemical reaction, the geometries and lifetimes of intermediate complexes that govern the reaction dynamics, and the collision energy dependence of these dynamical features. The author employs crossed-beam low energy mass spectrometry technology developed over the last several years, with the focus of current research on proton transfer and hydrogen atom transfer reactions of te O{sup {minus}} ion with species such as HF, H{sub 2}O, and NH{sub 3}.

  16. On the kinetic energy density

    International Nuclear Information System (INIS)

    Lombard, R.J.; Mas, D.; Moszkowski, S.A.

    1991-01-01

    We discuss two expressions for the density of kinetic energy which differ by an integration by parts. Using the Wigner transform we shown that the arithmetic mean of these two terms is closely analogous to the classical value. Harmonic oscillator wavefunctions are used to illustrate the radial dependence of these expressions. We study the differences they induce through effective mass terms when performing self-consistent calculations. (author)

  17. Fragmentation of cluster ions produced by electron impact ionization

    International Nuclear Information System (INIS)

    Parajuli, R.

    2001-12-01

    By studying fragmentation of dimer and cluster ions produced by electron impact ionization of a neutral cluster beam, it is possible to elucidate structure, stability and energetics of these species and the dynamics of the corresponding decay reactions. Fragmentation of carbon cluster ions formed from C 6 0 fullerenes, rare gas cluster ions and dimer ions and simple molecular cluster ions (oxygen and nitrogen) and dimer ions have been studied in this thesis using a high resolution two sector field mass spectrometer of reversed geometry and a NIER type electron impact ion source. Spontaneous decay reactions of triply and quadruply charged C 4 0 z + and C 4 1 z + cluster ions which are formed from C 6 0 fullerenes by electron impact ionization have been analyzed. A new but very weak decay reaction for the even-sized carbon clusters ions is observed, namely loss of C 3 . The odd-sized clusters ions preferentially decay by loss of carbon atoms and, to a lesser degree, trimers. A weak signal due to C 2 loss is observed for C 4 1 3 + ion. These decay channels are discussed in terms of the geometric structure of these metastable, relatively cold cluster ions. Measurements on metastable fragmentation of mass selected rare gas cluster ions (Ne, Ar, Kr) which are produced by electron impact ionization of a neutral rare gas cluster beam have been carried out. From the shape of the fragment ion peaks (MIKE scan technique) information about the distribution of kinetic energy that is released in the decay reaction can be deduced. In this study, the peak shape observed for cluster ions with sizes larger than five is Gaussian and thus from the peak width the mean kinetic energy release of the corresponding decay reactions can be calculated. Using finite heat bath theory, the binding energies of the decaying cluster ions are calculated from these data and have been compared to data in the literature where available. In addition to the decay reactions of cluster ions the metastable

  18. Kinetic-energy distribution for symmetric fission of 236U

    International Nuclear Information System (INIS)

    Brissot, R.; Bocquet, J.P.; Ristori, C.; Crancon, J.; Guet, C.R.; Nifenecker, H.A.; Montoya, M.

    1980-01-01

    Fission fragment kinetic-energy distributions have been measured at the Grenoble high-flux reactor with the Lohengrin facility. Spurious events were eliminated in the symmetric region by a coherence test based on a time-of-flight measurement of fragment velocities. A Monte-Carlo calculation is then performed to correct the experimental data for neutron evaporation. The difference between the most probable kinetic energy in symmetric fission and the fission in which the heavy fragment is 'magic' (Zsub(H)=50) is found to be approximately =30 MeV. The results suggest that for the symmetric case the total excitation energy available at scission is shared equally among the fragments. (author)

  19. Low-energy ion outflow modulated by the solar wind energy input

    Science.gov (United States)

    Li, Kun; Wei, Yong; Andre, Mats; Eriksson, Anders; Haaland, Stein; Kronberg, Elena; Nilsson, Hans; Maes, Lukas

    2017-04-01

    Due to the spacecraft charging issue, it has been difficult to measure low-energy ions of ionospheric origin in the magnetosphere. A recent study taking advantage of the spacecraft electric potential has found that the previously 'hidden' low-energy ions is dominant in the magnetosphere. This comprehensive dataset of low-energy ions allows us to study the relationship between the ionospheric outflow and energy input from the solar wind (ɛ). In this study, we discuss the ratios of the solar wind energy input to the energy of the ionospheric outflow. We show that the ɛ controls the ionospheric outflow when the ɛ is high, while the ionospheric outflow does not systematically change with the ɛ when the ɛ is low.

  20. Kinetic-energy density functional: Atoms and shell structure

    International Nuclear Information System (INIS)

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.

    1996-01-01

    We present a nonlocal kinetic-energy functional which includes an anisotropic average of the density through a symmetrization procedure. This functional allows a better description of the nonlocal effects of the electron system. The main consequence of the symmetrization is the appearance of a clear shell structure in the atomic density profiles, obtained after the minimization of the total energy. Although previous results with some of the nonlocal kinetic functionals have given incipient structures for heavy atoms, only our functional shows a clear shell structure for most of the atoms. The atomic total energies have a good agreement with the exact calculations. Discussion of the chemical potential and the first ionization potential in atoms is included. The functional is also extended to spin-polarized systems. copyright 1996 The American Physical Society

  1. Ion energy/momentum effects during ion assisted growth of niobium nitride films

    Science.gov (United States)

    Klingenberg, Melissa L.

    The research described herein was performed to better understand and discern ion energy vs. ion momentum effects during ion beam assisted (IBAD) film growth and their effects on residual stress, crystalline structure, morphology, and composition, which influence film tribological properties. NbxN y was chosen for this research because it is a refractory material that can possess a large number of crystalline structures, and it has been found to have good tribological properties. To separate the effects of momentum transfer per arriving atom (p/a), which considers bombarding species mass, energy, and ion-to-atom transport ratio, from those of energy deposition per arriving atom (E/a), a mass independent parameter, different inert ion beams (krypton, argon, and neon) were used to create a matrix of coatings formed using similar energy deposition, but different momentum transfer and vice versa. Deposition was conducted in a research-scale IBAD system using electron beam evaporation, a radio frequency ion source, and a neutral nitrogen gas backfill. Films were characterized using x-ray diffraction, atomic force microscopy, Rutherford backscattering spectrometry, and residual stress analysis. Direct and quantifiable effects of bombardment were observed; however, energy deposition and momentum transfer effects could not be completely separated, confirming that thin film processes are complex. Complexities arose from ion-specific interactions (ion size, recoil energy, per cent reflected neutrals, Penning ionization, etc.) and chemistry effects that are not considered by the simple models. Overall, it can be stated that bombardment promoted nitride formation, nanocrystallinity, and compressive stress formation; influenced morphology (which influenced post-deposition oxygen uptake) and stress evolution; increased lattice parameter; modified crystalline phase and texture; and led to inert gas incorporation. High stress levels correlated strongly with material disorder and

  2. Energy straggling of heavy ions in solids

    International Nuclear Information System (INIS)

    Cowern, N.E.B.

    1979-08-01

    The energy-loss straggling of heavy ions has been studied, principally in the Born Approximation region v > zv 0 . Measurements were made with 5.486 MeV α particles, 5 - 48 MeV 16 0 ions, and 3 - 36 MeV 12 C ions, incident on thin uniform Al foils. The thickness uniformity of the foils was studied with a proton microbeam and a surface profiler, and their homogeneity, purity and isotropy were investigated by electron microscope, proton backscattering, and X-ray diffraction studies. Using the Bethe theory of energy loss the charge-exchange model of energy straggling for heavy ions is confirmed. (author)

  3. Multicavity SCRF calculation of ion hydration energies

    International Nuclear Information System (INIS)

    Diercksen, B.H.F.; Karelson, M.; Tamm, T.

    1994-01-01

    The hydration energies of the proton, hydroxyl ion, and several inorganic ions were calculated using the multicavity self-consistent reaction field (MCa SCRF) method developed for the quantum-mechanical modeling of rotationally or flexible systems in dielectric media. The ionic complexes H 3 O + (H2O) 4 , OH - (H2O) 4 , NH + 4 (H2O) 4 , and Hal - (H2O) 4 , where Hal = F, Cl, or Br, have been studied. Each complex was divided between five spheres, corresponding to the central ion and four water molecules in their first coordination sphere, respectively. Each cavity was surrounded by a polarizable medium with the dielectric permittivity of water at room temperature (80). The ionic hydration energies of ions were divided into specific and nonspecific parts. After accounting for the cavity-formation energy using scaled particle theory, good agreement between the total calculated and experimental hydration energies was obtained for all ions studied

  4. Ulysses observations of magnetic waves due to newborn interstellar pickup ions. II. Application of turbulence concepts to limiting wave energy and observability

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Bradford E. [Physics Department, Florida State University, Tallahassee, FL 32306 (United States); Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J. [Physics Department and Space Science Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824 (United States); Murphy, Neil [Jet Propulsion Laboratory, Mail Stop 180-600, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Nuno, Raquel G., E-mail: bc13h@my.fsu.edu, E-mail: Charles.Smith@unh.edu, E-mail: Phil.Isenberg@unh.edu, E-mail: Bernie.Vasquez@unh.edu, E-mail: cjl46@wildcats.unh.edu, E-mail: Neil.Murphy@jpl.nasa.gov, E-mail: raquel.nuno@asu.edu [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)

    2014-06-01

    The low-frequency magnetic waves that arise from the isotropization of newborn interstellar pickup ions (PUIs) are reasonably well described by linear and quasi-linear kinetic theory in so far as those theories predict the wave frequency and polarization in the spacecraft frame. Those theories fail to describe the scarce observability of the waves. Quasilinear theory predicts that the wave power should accumulate over long periods of time as the relatively weak kinetic instability slowly adds power to the observed spectrum. At the same time it has been argued that the same wave energy must serve as a secondary source of thermal ion heating in the outer heliosphere once the initial turbulence is depleted. To the extent that turbulent transport of the wave energy acts against the spectrally confined accumulation of wave energy, turbulence should be a limiting factor in observability. We argue that turbulence does limit the observability of the waves and we use turbulence theory to predict the observed wave energy. We compare this prediction against a database of 502 wave observations attributed to newborn interstellar PUIs observed by the Ulysses spacecraft.

  5. Ulysses observations of magnetic waves due to newborn interstellar pickup ions. II. Application of turbulence concepts to limiting wave energy and observability

    International Nuclear Information System (INIS)

    Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G.

    2014-01-01

    The low-frequency magnetic waves that arise from the isotropization of newborn interstellar pickup ions (PUIs) are reasonably well described by linear and quasi-linear kinetic theory in so far as those theories predict the wave frequency and polarization in the spacecraft frame. Those theories fail to describe the scarce observability of the waves. Quasilinear theory predicts that the wave power should accumulate over long periods of time as the relatively weak kinetic instability slowly adds power to the observed spectrum. At the same time it has been argued that the same wave energy must serve as a secondary source of thermal ion heating in the outer heliosphere once the initial turbulence is depleted. To the extent that turbulent transport of the wave energy acts against the spectrally confined accumulation of wave energy, turbulence should be a limiting factor in observability. We argue that turbulence does limit the observability of the waves and we use turbulence theory to predict the observed wave energy. We compare this prediction against a database of 502 wave observations attributed to newborn interstellar PUIs observed by the Ulysses spacecraft.

  6. Adsorption Kinetics and intra particulate diffusivities of Hg, As and Pb ions on unmodified and thiolated coconut fiber

    International Nuclear Information System (INIS)

    Igwe, J. C.; Abia, A. A.; Ibeh, C. A.

    2008-01-01

    As, Hg and Pb are examples of heavy metals which are present in different types of industrial effluents responsible for environmental pollution. Their removal is traditionally made by chemical precipitation, ion-exchange and so on. However, this is expensive and not completely feasible to reduce their concentrations to the levels as low as required by the environmental legislation. Bio sorption is a process in which solids of natural origin are employed for binding the heavy metal. It is a promising alternative method to treat industrial effluents, mainly because of its low cost and high metal binding capacity. The kinetics was studied for bio sorption experiments using coconut fiber for As (III), Hg (II) and Pb (II) ions adsorption. The specific surface area and surface charge density of the coconut fiber are 1.186x10 25 (m 2 /g) and 5.39 xI0 24 (meq/m 2 ), respectively. The maximum adsorption capacity was found to be the highest for Pb (II) followed by Hg (II) and As (Ill). The modification of the adsorbent by thiolation affected the adsorption capacity. Equilibrium sorption was reached for the metal ions at about 60 min. The equilibrium constant and free energy of the adsorption at 30 degree were calculated. The mechanism of sorption was found to obey the particle-diffusion model. The kinetic studies showed that the sorption rates could be described by both pseudo first-order and pseudo second-order models. The pseudo second-order model showed a better fit with a rate constant value of 1.16x10 -4 /min. for all three metal ions.Therefore, the results of this study show that coconut fiber, both modified and unmodified, is an efficient adsorbent for the removal of toxic and valuable metals from industrial effluents

  7. Kinetic Monte Carlo Study of Ambipolar Lithium Ion and Electron-Polaron Diffusion into Nanostructured TiO2

    International Nuclear Information System (INIS)

    Yu, Jianguo; Sushko, Maria L.; Kerisit, Sebastien N.; Rosso, Kevin M.; Liu, Jun

    2012-01-01

    Nanostructured titania (TiO2) polymorphs have proved to be promising electrode materials for next generation lithium-ion batteries. However, there is still a lack of understanding of the fundamental microscopic processes that control charge transport in these materials. Here we present microscopic simulations of the collective dynamics of lithium-ion (Li+) and charge compensating electron polarons (e-) in rutile TiO2 nanoparticles in contact with idealized conductive matrix and electrolyte. Kinetic Monte Carlo simulations are used, parameterized by molecular dynamics-based predictions of activation energy barriers for Li+ and e- diffusion. Simulations reveal the central role of electrostatic coupling between Li+ and e- on their collective drift diffusion at the nanoscale. They also demonstrate that high contact area between conductive matrix and rutile nanoparticles leads to undesirable coupling-induced surface saturation effects during Li+ insertion, which limits the overall capacity and conductivity of the material. These results help provide guidelines for design of nanostructured electrode materials with improved electrochemical performance.

  8. Fabrication and demonstration of high energy density lithium ion microbatteries

    Science.gov (United States)

    Sun, Ke

    density on a limited footprint area. In chapter 4, Li-ion batteries based on the LiMn2O4-TiP 2O7 couple are manufactured on flexible paper substrates; where the use of light-weight paper substrates significantly increase the gravimetric energy density of this electrode couple as compared to traditional metal current collectors. In chapter 5, a novel nanowire growth mechanism will be explored to grow interdigitated metal oxide nanowire micro battery electrodes. The growth kinetics of this mechanism is systematically studied to understand how to optimize the growth process to produce electrodes with improved electrochemical properties.

  9. PFI-ZEKE (Pulsed Field Ionization-Zero Electron Kinetic Energy) para el estudio de iones

    Science.gov (United States)

    Castaño, F.; Fernández, J. A.; Basterretxea, A. Longarte. F.; Sánchez Rayo, M. N.; Martínez, R.

    Entre las áreas hacia donde ha evolucionado la Química en los últimos años están los estudios de sistemas con especies reactivas de alta energía y los dominados por fuerzas intermoleculares débiles, con energías de unas pocas kcal/mol. En efecto, el estudio de las propiedades de los iones, comenzando por su relación con la molécula neutra de la que procede, la energía de ionización, los estados vibracionales y rotacionales, energías de enlace de Van der Waals entre el ión y una amplia variedad de otras moléculas, sus confórmeros o isómeros y sus reacciones o semi-reacciones químicas están en la raíz de la necesidad de la espectroscopía conocida como PFI-ZEKE, Pulsed Field Ionization-Zero Electron Kinetic Energy. Entre las aplicaciones que requieren estos conocimientos se encuentran la generación de plasmas para la fabricación de semiconductores, memorias magnéticas, etc, así como los sistemas astrofísicos, la ionosfera terrestre, etc. La espectroscopía ZEKE es una evolución de las de fluorescencia inducida por láser, LIF, ionización multifotónica acrecentada por resonancia, REMPI, con uno y dos colores y acoplada a un sistema de tiempo de vuelo, REMPI-TOF-MS, y las espectroscopías de doble resonancia IR-UV y UV-UV. Sus espectros y la ayuda de cálculos ab inicio permite determinar las energías de enlace de complejos de van der Waals en estados fundamental y excitados, identificar confórmeros e isómeros, obtener energías de ionización experimentales aproximadas (100 cm-1) y otras variables de interés. Al igual que con LIF, REMPI y dobles resonancias, es posible utilizar muestras gaseosas, pero los espectros están muy saturados de bandas y su interpretación es difícil o imposible. Se evitan estas dificultades estudiando las moléculas o complejos en expansiones supersónicas, donde la T de los grados de libertad solo alcanzan unos pocos K. Para realizar experimentos de ZEKE hay que utilizar una propiedad recientemente

  10. Kinetic Alfven wave in the presence of kappa distribution function in plasma sheet boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, G., E-mail: geetphy9@gmail.com; Ahirwar, G. [School of Studies in Physics, Vikram University, Ujjain India (India); Shrivastava, J., E-mail: jayashrivastava2007@gmail.com [Dronacharya Group of Institutions, Greater Noida-India (India)

    2015-07-31

    The particle aspect approach is adopted to investigate the trajectories of charged particles in the electromagnetic field of kinetic Alfven wave. Expressions are found for the dispersion relation, damping/growth rate and associated currents in the presence of kappa distribution function. Kinetic effect of electrons and ions are included to study kinetic Alfven wave because both are important in the transition region. It is found that the ratio β of electron thermal energy density to magnetic field energy density and the ratio of ion to electron thermal temperature (T{sub i}/T{sub e}), and kappa distribution function affect the dispersion relation, damping/growth rate and associated currents in both cases(warm and cold electron limit).The treatment of kinetic Alfven wave instability is based on assumption that the plasma consist of resonant and non resonant particles. The resonant particles participate in an energy exchange process, whereas the non resonant particles support the oscillatory motion of the wave.

  11. A high-flux low-energy hydrogen ion beam using an end-Hall ion source

    NARCIS (Netherlands)

    Veldhoven, J. van; Sligte, E. te; Janssen, J.P.B.

    2016-01-01

    Most ion sources that produce high-flux hydrogen ion beams perform best in the high energy range (keV). Alternatively, some plasma sources produce very-lowenergy ions (<< 10 eV). However, in an intermediate energy range of 10-200 eV, no hydrogen ion sources were found that produce high-flux beams.

  12. Species Entropies in the Kinetic Range of Collisionless Plasma Turbulence: Particle-in-cell Simulations

    Science.gov (United States)

    Gary, S. Peter; Zhao, Yinjian; Hughes, R. Scott; Wang, Joseph; Parashar, Tulasi N.

    2018-06-01

    Three-dimensional particle-in-cell simulations of the forward cascade of decaying turbulence in the relatively short-wavelength kinetic range have been carried out as initial-value problems on collisionless, homogeneous, magnetized electron-ion plasma models. The simulations have addressed both whistler turbulence at β i = β e = 0.25 and kinetic Alfvén turbulence at β i = β e = 0.50, computing the species energy dissipation rates as well as the increase of the Boltzmann entropies for both ions and electrons as functions of the initial dimensionless fluctuating magnetic field energy density ε o in the range 0 ≤ ε o ≤ 0.50. This study shows that electron and ion entropies display similar rates of increase and that all four entropy rates increase approximately as ε o , consistent with the assumption that the quasilinear premise is valid for the initial conditions assumed for these simulations. The simulations further predict that the time rates of ion entropy increase should be substantially greater for kinetic Alfvén turbulence than for whistler turbulence.

  13. A Particle X-ray Temporal Diagnostic (PXTD) for studies of kinetic, multi-ion effects, and ion-electron equilibration rates in Inertial Confinement Fusion plasmas at OMEGA (invited)

    International Nuclear Information System (INIS)

    Sio, H.; Frenje, J. A.; Katz, J.; Stoeckl, C.; Weiner, D.

    2016-01-01

    Here, a Particle X-ray Temporal Diagnostic (PXTD) has been implemented on OMEGA for simultaneous time-resolved measurements of several nuclear products as well as the x-ray continuum produced in High Energy Density Plasmas and Inertial Confinement Fusion implosions. The PXTD removes systematic timing uncertainties typically introduced by using multiple instruments, and it has been used to measure DD, DT, D"3He, and T"3He reaction histories and the emission history of the x-ray core continuum with relative timing uncertainties within ±10-20 ps. This enables, for the first time, accurate and simultaneous measurements of the x-ray emission histories, nuclear reaction histories, their time differences, and measurements of T_i(t) and T_e(t) from which an assessment of multiple-ion-fluid effects, kinetic effects during the shock-burn phase, and ion-electron equilibration rates can be made.

  14. The eddy kinetic energy budget in the Red Sea

    KAUST Repository

    Zhan, Peng

    2016-06-09

    The budget of eddy kinetic energy (EKE) in the Red Sea, including the sources, redistributions and sink, is examined using a high-resolution eddy-resolving ocean circulation model. A pronounced seasonally varying EKE is identified, with its maximum intensity occurring in winter, and the strongest EKE is captured mainly in the central and northern basins within the upper 200 m. Eddies acquire kinetic energy from conversion of eddy available potential energy (EPE), from transfer of mean kinetic energy (MKE), and from direct generation due to time-varying (turbulent) wind stress, the first of which contributes predominantly to the majority of the EKE. The EPE-to-EKE conversion occurs almost in the entire basin, while the MKE-to-EKE transfer appears mainly along the shelf boundary of the basin (200 miso-bath) where high horizontal shear interacts with topography. The EKE generated by the turbulent wind stress is relatively small and limited to the southern basin. All these processes are intensified during winter, when the rate of energy conversion is about four to five times larger than that in summer. The EKE is redistributed by the vertical and horizontal divergence of energy flux and the advection of the mean flow. As a main sink of EKE, dissipation processes is ubiquitously found in the basin. The seasonal variability of these energy conversion terms can explain the significant seasonality of eddy activities in the Red Sea. This article is protected by copyright. All rights reserved.

  15. A generalized electron energy probability function for inductively coupled plasmas under conditions of nonlocal electron kinetics

    Science.gov (United States)

    Mouchtouris, S.; Kokkoris, G.

    2018-01-01

    A generalized equation for the electron energy probability function (EEPF) of inductively coupled Ar plasmas is proposed under conditions of nonlocal electron kinetics and diffusive cooling. The proposed equation describes the local EEPF in a discharge and the independent variable is the kinetic energy of electrons. The EEPF consists of a bulk and a depleted tail part and incorporates the effect of the plasma potential, Vp, and pressure. Due to diffusive cooling, the break point of the EEPF is eVp. The pressure alters the shape of the bulk and the slope of the tail part. The parameters of the proposed EEPF are extracted by fitting to measure EEPFs (at one point in the reactor) at different pressures. By coupling the proposed EEPF with a hybrid plasma model, measurements in the gaseous electronics conference reference reactor concerning (a) the electron density and temperature and the plasma potential, either spatially resolved or at different pressure (10-50 mTorr) and power, and (b) the ion current density of the electrode, are well reproduced. The effect of the choice of the EEPF on the results is investigated by a comparison to an EEPF coming from the Boltzmann equation (local electron kinetics approach) and to a Maxwellian EEPF. The accuracy of the results and the fact that the proposed EEPF is predefined renders its use a reliable alternative with a low computational cost compared to stochastic electron kinetic models at low pressure conditions, which can be extended to other gases and/or different electron heating mechanisms.

  16. Removal of Pb(II) ions from aqueous solution by a waste mud from copper mine industry: equilibrium, kinetic and thermodynamic study.

    Science.gov (United States)

    Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa

    2009-07-30

    The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g(-1) for 10 g L(-1) of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees), and entropy (DeltaS degrees) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 degrees C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.

  17. Removal of Pb(II) ions from aqueous solution by a waste mud from copper mine industry: Equilibrium, kinetic and thermodynamic study

    International Nuclear Information System (INIS)

    Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa

    2009-01-01

    The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g -1 for 10 g L -1 of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (ΔG o ), enthalpy (ΔH o ), and entropy (ΔS o ) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 o C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.

  18. Removal of Pb(II) ions from aqueous solution by a waste mud from copper mine industry: Equilibrium, kinetic and thermodynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri [Department of Chemistry, Karadeniz Technical University, Faculty of Arts and Sciences, 61080 Trabzon (Turkey); Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr [Department of Chemistry, Erciyes University, Faculty of Arts and Sciences, 38039 Kayseri (Turkey)

    2009-07-30

    The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g{sup -1} for 10 g L{sup -1} of a-WM concentration. Thermodynamic parameters including the Gibbs free energy ({Delta}G{sup o}), enthalpy ({Delta}H{sup o}), and entropy ({Delta}S{sup o}) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 {sup o}C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.

  19. Energy dissipation of highly charged ions interacting with solid surfaces; Energieeintrag langsamer hochgeladener Ionen in Festkoerperoberflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Kost, D.

    2006-07-01

    Motivated by the incomplete scientific description of the relaxation of highly charged ions in front of solid surfaces and their energy balance, this thesis describes an advanced complementary study of determining deposited fractions and re-emitted fractions of the potential energy of highly charged ions. On one side, a calorimetric measurement setup is used to determine the retained potential energy and on the other side, energy resolved electron spectroscopy is used for measuring the reemitted energy due to secondary electron emission. In order to study the mechanism of energy retention in detail, materials with different electronic structures are investigated: Cu, n-Si, p-Si and SiO{sub 2}. In the case of calorimetry, a linear relationship between the deposited potential energy and the inner potential energy of the ions was determined. The total potential energy which stays in the solid remains almost constant at about (80 {+-} 10) %. Comparing the results of the Cu, n-Si and p-Si targets, no significant difference could be shown. Therefore we conclude that the difference in energy deposition between copper, n-doped Si and p-doped Si is below 10 %, which is significantly lower than using SiO{sub 2} targets. For this purpose, electron spectroscopy provides a complementary result. For Cu and Si surfaces, an almost linear increase of the re-emitted energy with increasing potential energy of the ion up to Ar{sup 7+} was also observed. The ratio of the re-emitted energy is about (10 {+-} 5) % of the total potential energy of the incoming ion, almost independent of the ion charge state. In contrast, an almost vanishing electron emission was observed for SiO{sub 2} and for charge states below q=7. For Ar{sup 8+} and Ar{sup 9+}, the electron emission increased due to the contribution of the projectile LMM Auger electrons and the re-emitted energy amounts up to 20 % for Cu and Si and around 10 % for SiO{sub 2}. These results are in good agreement with the calorimetric

  20. Small amplitude Kinetic Alfven waves in a superthermal electron-positron-ion plasma

    Science.gov (United States)

    Adnan, Muhammad; Mahmood, Sahahzad; Qamar, Anisa; Tribeche, Mouloud

    2016-11-01

    We are investigating the propagating properties of coupled Kinetic Alfven-acoustic waves in a low beta plasma having superthermal electrons and positrons. Using the standard reductive perturbation method, a nonlinear Korteweg-de Vries (KdV) type equation is derived which describes the evolution of Kinetic Alfven waves. It is found that nonlinearity and Larmor radius effects can compromise and give rise to solitary structures. The parametric role of superthermality and positron content on the characteristics of solitary wave structures is also investigated. It is found that only sub-Alfvenic and compressive solitons are supported in the present model. The present study may find applications in a low β electron-positron-ion plasma having superthermal electrons and positrons.

  1. Low flux and low energy helium ion implantation into tungsten using a dedicated plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Pentecoste, Lucile [GREMI, CNRS/Université d’Orléans, 14 rue d’Issoudun, B.P. 6744, 45067 Orléans Cedex2 (France); Thomann, Anne-Lise, E-mail: anne-lise.thomann@univ-orleans.fr [GREMI, CNRS/Université d’Orléans, 14 rue d’Issoudun, B.P. 6744, 45067 Orléans Cedex2 (France); Melhem, Amer; Caillard, Amael; Cuynet, Stéphane; Lecas, Thomas; Brault, Pascal [GREMI, CNRS/Université d’Orléans, 14 rue d’Issoudun, B.P. 6744, 45067 Orléans Cedex2 (France); Desgardin, Pierre; Barthe, Marie-France [CNRS, UPR3079 CEMHTI, 1D avenue de la Recherche Scientifique, 45071 Orléans Cedex2 (France)

    2016-09-15

    The aim of this work is to investigate the first stages of defect formation in tungsten (W) due to the accumulation of helium (He) atoms inside the crystal lattice. To reach the required implantation conditions, i.e. low He ion fluxes (10{sup 11}–10{sup 14} ions.cm{sup 2}.s{sup −1}) and kinetic energies below the W atom displacement threshold (about 500 eV for He{sup +}), an ICP source has been designed and connected to a diffusion chamber. Implantation conditions have been characterized by means of complementary diagnostics modified for measurements in this very low density helium plasma. It was shown that lowest ion fluxes could only be reached for the discharge working in capacitive mode either in α or γ regime. Special attention was paid to control the energy gained by the ions by acceleration through the sheath at the direct current biased substrate. At very low helium pressure, in α regime, a broad ion energy distribution function was evidenced, whereas a peak centered on the potential difference between the plasma and the biased substrate was found at higher pressures in the γ mode. Polycrystalline tungsten samples were exposed to the helium plasma in both regimes of the discharge and characterized by positron annihilation spectroscopy in order to detect the formed vacancy defects. It was found that W vacancies are able to be formed just by helium accumulation and that the same final implanted state is reached, whatever the operating mode of the capacitive discharge.

  2. Temperatures of fragment kinetic energy spectra

    International Nuclear Information System (INIS)

    Bauer, W.

    1995-01-01

    Multifragmentation reactions without large compression in the initial state (proton-induced reactions, reverse kinematics, projectile fragmentation) are examined, and it is verified quantitatively that the high temperatures obtained from fragment kinetic energy spectra and lower temperatures obtained from observables such as level population or isotope ratios can be understood in a common framework

  3. Kinetic Energy of a Trapped Fermi Gas at Finite Temperature

    Science.gov (United States)

    Grela, Jacek; Majumdar, Satya N.; Schehr, Grégory

    2017-09-01

    We study the statistics of the kinetic (or, equivalently, potential) energy for N noninteracting fermions in a 1 d harmonic trap of frequency ω at finite temperature T . Remarkably, we find an exact solution for the full distribution of the kinetic energy, at any temperature T and for any N , using a nontrivial mapping to an integrable Calogero-Moser-Sutherland model. As a function of temperature T and for large N , we identify (i) a quantum regime, for T ˜ℏω , where quantum fluctuations dominate and (ii) a thermal regime, for T ˜N ℏω , governed by thermal fluctuations. We show how the mean and the variance as well as the large deviation function associated with the distribution of the kinetic energy cross over from the quantum to the thermal regime as T increases.

  4. High-current heavy-ion accelerator system and its application to material modification

    International Nuclear Information System (INIS)

    Kishimoto, Naoki; Takeda, Yoshihiko; Lee, C.G.; Umeda, Naoki; Okubo, Nariaki; Iwamoto, Eiji

    2001-01-01

    A high-current heavy-ion accelerator system has been developed to realize intense particle fluxes for material modification. The facility of a tandem accelerator attained 1 mA-class ion current both for negative low-energy ions and positive high-energy ions. The negative ion source of the key device is of the plasma-sputter type, equipped with mutli-cusp magnets and Cs supply. The intense negative ions are either directly used for material irradiation at 60 keV or further accelerated up to 6 MeV after charge transformation. Application of negative ions, which alleviates surface charging, enables us to conduct low-energy high-current irradiation on insulating substrates. Since positive ions above the MeV range are irrelevant for Coulomb repulsion, the facility as a whole meets the needs of high-current irradiation onto insulators over a wide energy range. Application of high flux ions provides technological merits not only for efficient implantation but also for essentially different material kinetics, which may become an important tool of material modification. Other advantages of the system are co-irradiation by intense laser and in-situ detection of kinetic processes. For examples of material modifications, we present nanoparticle fabrication in insulators, and synergistic phenomena by co-irradiation due to ions and photons. (author)

  5. Sulfate radical-based degradation of polychlorinated biphenyls: Effects of chloride ion and reaction kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Guo-Dong [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Dionysiou, Dionysios D. [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0071 (United States); Wang, Yu [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Al-Abed, Souhail R. [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States); Zhou, Dong-Mei, E-mail: dmzhou@issas.ac.cn [Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer A kinetic model was used to predict the radical species and their distributions. Black-Right-Pointing-Pointer The generated radical species were identified by EPR. Black-Right-Pointing-Pointer The second-order rate constants of sulfate radical with PCBs were determined. - Abstract: Advanced oxidation processes (AOPs) based on sulfate radical (SO{sub 4}{center_dot}{sup -}) have been recently used for soil and groundwater remediation. The presence of chloride ion in natural or wastewater decreases the reactivity of sulfate radical system, but explanations for this behavior were inconsistent, and the mechanisms are poorly understood. Therefore, in this paper we investigated the effect of chloride ion on the degradation of 2,4,4 Prime -CB (PCB28) and biphenyl (BP) by persulfate, based on the produced SO{sub 4}{center_dot}{sup -}. The results showed that the presence of chloride ion greatly inhibited the transformation of PCB28 and BP. Transformation intermediates of BP were monitored, suggesting that the chloride ion can react with SO{sub 4}{center_dot}{sup -} to produce chlorine radical, which reacts with BP to generate chlorinated compounds. To better understand the underlying mechanisms of these processes, a kinetic model was developed for predicting the effect of chloride ion on the types of radical species and their distributions. The results showed that chloride ion could influence the selectivity of radical species and their distribution, and increase the concentration of the sum of radical species. In addition, the second-order rate constants of sulfate radical with PCBs were determined, and quantum-chemical descriptors were introduced to predict the rate constants of other PCBs based on our experimental data.

  6. Femto-clock for the electron kinetics in swift heavy ion tracks

    Czech Academy of Sciences Publication Activity Database

    Medvedev, Nikita; Volkov, A.E.

    2017-01-01

    Roč. 50, č. 44 (2017), s. 1-11, č. článku 445302. ISSN 0022-3727 R&D Projects: GA MŠk LG15013; GA MŠk(CZ) LM2015083 Institutional support: RVO:68378271 Keywords : swift heavy ions * electron kinetics * femto-clock * femtosecond resolution * spectroscopy * radiative decay Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.588, year: 2016

  7. Kinetic theory of plasma in the limiter-scrape-off layer

    International Nuclear Information System (INIS)

    Daybelge, U.; Bein, B.

    1977-01-01

    An asymptotic solution is given for the ion-drift-kinetic equation with a full Fokker--Planck term for the limiter-scrape-off layer in a tokamak. In this layer, the plasma is assumed to consist of hot, collisionless ions, and cold, collisional electrons. From the solution of the boundary-layer problem, ion and electron particle and energy losses to the limiter are calculated. Limiter load profiles due to ions are explicitly given as functions of the poloidal angle

  8. Effect of high energy electrons on H⁻ production and destruction in a high current DC negative ion source for cyclotron.

    Science.gov (United States)

    Onai, M; Etoh, H; Aoki, Y; Shibata, T; Mattei, S; Fujita, S; Hatayama, A; Lettry, J

    2016-02-01

    Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H(-) production. The modelling results reasonably explains the dependence of the H(-) extraction current on the arc-discharge power in the experiments.

  9. Mechanical and structural properties of fluorine-ion-implanted boron suboxide

    CSIR Research Space (South Africa)

    Machaka, R

    2011-09-01

    Full Text Available such as diffusion, solubility, deposi- tion, and alloy formation by providing high kinetic energy through ion impact and utilizing ballistic effects during ion- solid interaction [1?4]. Moreover, ion implantation allows the precise control of the ion energy, ion... annealing, and diffusion processes taking place during ion implantation. Advances in Materials Science and Engineering 3 Acc. V Det WD 5 ?m 512 kV 5000x CL 11.9 B6O Spot Magn (a) 0 1 2 3 4 5 6 7 8 0 0.3 0.6 0.9 1.3 1.6 KC n t Energy (keV) B...

  10. Rechargeable dual-metal-ion batteries for advanced energy storage.

    Science.gov (United States)

    Yao, Hu-Rong; You, Ya; Yin, Ya-Xia; Wan, Li-Jun; Guo, Yu-Guo

    2016-04-14

    Energy storage devices are more important today than any time before in human history due to the increasing demand for clean and sustainable energy. Rechargeable batteries are emerging as the most efficient energy storage technology for a wide range of portable devices, grids and electronic vehicles. Future generations of batteries are required to have high gravimetric and volumetric energy, high power density, low price, long cycle life, high safety and low self-discharge properties. However, it is quite challenging to achieve the above properties simultaneously in state-of-the-art single metal ion batteries (e.g. Li-ion batteries, Na-ion batteries and Mg-ion batteries). In this contribution, hybrid-ion batteries in which various metal ions simultaneously engage to store energy are shown to provide a new perspective towards advanced energy storage: by connecting the respective advantages of different metal ion batteries they have recently attracted widespread attention due to their novel performances. The properties of hybrid-ion batteries are not simply the superposition of the performances of single ion batteries. To enable a distinct description, we only focus on dual-metal-ion batteries in this article, for which the design and the benefits are briefly discussed. We enumerate some new results about dual-metal-ion batteries and demonstrate the mechanism for improving performance based on knowledge from the literature and experiments. Although the search for hybrid-ion batteries is still at an early age, we believe that this strategy would be an excellent choice for breaking the inherent disadvantages of single ion batteries in the near future.

  11. Collective processes in heavy-ion collisions with atomic nuclei. Dissipation of energy and angular momentum

    International Nuclear Information System (INIS)

    Kuzminski, J.

    1980-01-01

    The collective processes in collision of heavy-ions with atomic nuclei are discussed. Measured data on the S+Ti collision at Esub(LAB)=105, 130 and 144 MeV have been analysed in terms of a ''fission-like'' processes which seem to be a special case of deep inelastic collisions whose total available kinetic energy is completely dissipated. Applying transport theory it was possible to introduce a ''clock'' for measuring the time scale of nuclear processes in collision of heavy-ions by measuring the FWHM of mass distribution of emitted reaction products. Experimental data on continuum gamma spectra from Cu+Au collision at Esub(LAB)=400 MeV are presented and the angular momentum dissipation in this reaction is discussed. (author)

  12. Raindrop Kinetic Energy Piezoelectric Harvesters and Relevant Interface Circuits: Review, Issues and Outlooks

    Directory of Open Access Journals (Sweden)

    Kok Gnee CHUA

    2016-05-01

    Full Text Available As an ecological source of renewable energy, the available kinetic energy of rainfall is not trifling, especially in tropical countries at the equators. The research on the use of piezoelectric transducer to harvest raindrop kinetic energy is gaining more and more attention recently. This article reviews the state-of-the-art energy harvesting technology from the conversion of raindrop kinetic energy using piezoelectric transducers as well as its interface circuits for vibration-based energy harvesters. Performance of different types of piezoelectric harvesters in terms of power output, area power density and energy conversion efficiency are compared. Summaries of key problems and suggestions on the optimization of the performance of the piezoelectric harvesters are also provided for future works.

  13. Neutron emission effects on final fragments mass and kinetic energy distribution from low energy fission of 234U

    International Nuclear Information System (INIS)

    Montoya, M.; Rojas, J.; Lobato, I.

    2008-01-01

    The standard deviation of the final kinetic energy distribution (σ e ) as a function of mass of final fragments (m) from low energy fission of 234 U, measured with the Lohengrin spectrometer by Belhafaf et al., presents a peak around m = 109 and another around m = 122. The authors attribute the first peak to the evaporation of a large number of neutrons around the corresponding mass number, i.e. there is no peak on the standard deviation of the primary kinetic energy distribution (σ E ) as a function of primary fragment mass (A). The second peak is attributed to a real peak on σ E (A). However, theoretical calculations related to primary distributions made by H.R. Faust and Z. Bao do not suggest any peak on σ E (A). In order to clarify this apparent controversy, we have made a numerical experiment in which the masses and the kinetic energy of final fragments are calculated, assuming an initial distribution of the kinetic energy without structures on the standard deviation as function of fragment mass. As a result we obtain a pronounced peak on σ e (m) curve around m = 109, a depletion from m = 121 to m = 129, and an small peak around m = 122, which is not as great as that measured by Belhafaf et al. Our simulation also reproduces the experimental results on the yield of the final mass Y(m), the average number of emitted neutrons as a function of the provisional mass (calculated from the values of the final kinetic energy of the complementary fragments) and the average value of fragment kinetic energy as a function of the final mass. From our results we conclude that there are no peaks on the σ E (A) curve, and the observed peaks on σ e (m) are due to the emitted neutron multiplicity and the variation of the average fragment kinetic energy as a function of primary fragment mass. (Author)

  14. Probing the rate-determining region of the potential energy surface for a prototypical ion-molecule reaction.

    Science.gov (United States)

    Xie, Changjian; Liu, Xinguo; Sweeny, Brendan C; Miller, Thomas M; Ard, Shaun G; Shuman, Nicholas S; Viggiano, Albert A; Guo, Hua

    2018-03-13

    We report a joint experimental-theoretical study of the F -  + HCl → HF + Cl - reaction kinetics. The experimental measurement of the rate coefficient at several temperatures was made using the selected ion flow tube method. Theoretical rate coefficients are calculated using the quasi-classical trajectory method on a newly developed global potential energy surface, obtained by fitting a large number of high-level ab initio points with augmentation of long-range electrostatic terms. In addition to good agreement between experiment and theory, analyses suggest that the ion-molecule reaction rate is significantly affected by shorter-range interactions, in addition to the traditionally recognized ion-dipole and ion-induced dipole terms. Furthermore, the statistical nature of the reaction is assessed by comparing the measured and calculated HF product vibrational state distributions to that predicted by the phase space theory.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).

  15. Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions

    International Nuclear Information System (INIS)

    Tso, Kin.

    1996-05-01

    The 129 Xe-induced reactions on nat Cu, 89 Y, 165 Ho, and 197 Au at bombarding energies of E/A = 40 ampersand 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the 129 Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied

  16. Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

    Science.gov (United States)

    Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

    2011-10-05

    This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms. © 2011 IOP Publishing Ltd

  17. Coordination kinetics of different metal ions with the amidoximated polyacrylonitrile nanofibrous membranes and catalytic behaviors of their complexes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fu; Dong, Yong Chun; Kang, Wei Min; Cheng, Bowen; Qu, Xiang; Cui, Guixin [School of Textiles, Tianjin Polytechnic University, Tianjin (China)

    2016-12-15

    Two transition metal ions (Fe{sup 3+} and Cu{sup 2+}) and a rare earth metal ion (Ce{sup 3+}) were selected to coordinate with amidoximated polyacrylonitrile (PAN) nanofibrous membrane for preparing three metal modified PAN nanofibrous membrane complexes (M-AO-n-PANs, M = Fe, Cu, or Ce) as the heterogeneous Fenton catalysts for the dye degradation in water under visible irradiation. The coordination kinetics of three metal ions with modified PAN nanofibrous membranes was studied and the catalytic properties of the resulting complexes were also compared. The results indicated that increasing metal ion concentrations in solution or higher coordination temperature led to a significant increase in metal content, particularly in Fe and Cu contents of the complexes. Their coordination process could be described using Langmuir isotherm and pseudo-second-order kinetic equations. Moreover, Fe-AO-n-PAN had the best photocatalytic efficiency for the dye degradation in acidic medium, but a lower photocatalytic activity than Cu-AO-n-PAN in alkali medium.

  18. In situ studies of the kinetics of surface topography development during ion irradiation

    International Nuclear Information System (INIS)

    Levinskas, R.; Pranevicius, L.

    1996-01-01

    Studies of the mechanical properties of the materials affected by 25-200 keV H + , He + , Ne + and Ar + ion irradiation in the range of fluences up to 2 · 10 17 cm -2 based on the analysis of acoustic emission signals, kinetics of the surface deformations measured by laser interferometric technique and the variations of the surface acoustic waves propagation velocity are conducted. The acoustic emissions source mechanisms under various ion irradiation conditions are discussed and relative contribution various possible mechanism are indicated. The correlation of experimental results obtained by different methods of analysis is done. (author). 11 refs, 5 figs

  19. Gas-Phase Hydrogen-Deuterium Exchange Labeling of Select Peptide Ion Conformer Types: a Per-Residue Kinetics Analysis.

    Science.gov (United States)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Tafreshian, Amirmahdi; Valentine, Stephen J

    2015-07-01

    The per-residue, gas-phase hydrogen deuterium exchange (HDX) kinetics for individual amino acid residues on selected ion conformer types of the model peptide KKDDDDDIIKIIK have been examined using ion mobility spectrometry (IMS) and HDX-tandem mass spectrometry (MS/MS) techniques. The [M + 4H](4+) ions exhibit two major conformer types with collision cross sections of 418 Å(2) and 446 Å(2); the [M + 3H](3+) ions also yield two different conformer types having collision cross sections of 340 Å(2) and 367 Å(2). Kinetics plots of HDX for individual amino acid residues reveal fast- and slow-exchanging hydrogens. The contributions of each amino acid residue to the overall conformer type rate constant have been estimated. For this peptide, N- and C-terminal K residues exhibit the greatest contributions for all ion conformer types. Interior D and I residues show decreased contributions. Several charge state trends are observed. On average, the D residues of the [M + 3H](3+) ions show faster HDX rate contributions compared with [M + 4H](4+) ions. In contrast the interior I8 and I9 residues show increased accessibility to exchange for the more elongated [M + 4H](4+) ion conformer type. The contribution of each residue to the overall uptake rate showed a good correlation with a residue hydrogen accessibility score model calculated using a distance from charge site and initial incorporation site for nominal structures obtained from molecular dynamic simulations (MDS).

  20. Scintillation screen materials for beam profile measurements of high energy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Krishnakumar, Renuka

    2016-06-22

    For the application as a transverse ion beam diagnostics device, various scintillation screen materials were analysed. The properties of the materials such as light output, image reproduction and radiation stability were investigated with the ion beams extracted from heavy ion synchrotron SIS-18. The ion species (C, Ne, Ar, Ta and U) were chosen to cover the large range of elements in the periodic table. The ions were accelerated to the kinetic energies of 200 MeV/u and 300 MeV/u extracted with 300 ms pulse duration and applied to the screens. The particle intensity of the ion beam was varied from 10{sup 4} to 10{sup 9} particles per pulse. The screens were irradiated with typically 40 beam pulses and the scintillation light was captured using a CCD camera followed by characterization of the beam spot. The radiation hardness of the screens was estimated with high intensity Uranium ion irradiation. In the study, a linear light output for 5 orders of magnitude of particle intensities was observed from sensitive scintillators and ceramic screens such as Al{sub 2}O{sub 3}:Cr and Al{sub 2}O{sub 3}. The highest light output was recorded by CsI:Tl and the lowest one by Herasil. At higher beam intensity saturation of light output was noticed from Y and Mg doped ZrO{sub 2} screens. The light output from the screen depends not only on the particle intensity but also on the ion species used for irradiation. The light yield (i.e. the light intensity normalised to the energy deposition in the material by the ion) is calculated from the experimental data for each ion beam setting. It is shown that the light yield for light ions is about a factor 2 larger than the one of heavy ions. The image widths recorded exhibit a dependence on the screens material and differences up to 50 % were registered. On radiation stability analysis with high particle intensity of Uranium ions of about 6 x 10{sup 8} ppp, a stable performance in light output and image reproduction was documented from Al

  1. From the Orbital Implementation of the Kinetic Theory to the Polarization Propagator Method in the Study of Energy Deposition Problems

    Science.gov (United States)

    Cabrera-Trujillo, R.; Cruz, S. A.; Soullard, J.

    The energy deposited by swift atomic-ion projectiles when colliding with a given target material has been a topic of special scientific interest for the last century due to the variety of applications of ion beams in modern materials technology as well as in medical physics. In this work, we summarize our contributions in this field as a consequence of fruitful discussions and enlightening ideas put forward by one of the main protagonists in stopping power theory during the last three decades: Jens Oddershede. Our review, mainly motivated by Jens' work, evolves from the extension of the orbital implementation of the kinetic theory of stopping through the orbital local plasma approximation, its use in studies of orbital and total mean excitation energies for the study of atomic and molecular stopping until the advances on generalized oscillator strength and sum rules in the study of stopping cross sections. Finally, as a tribute to Jens' work on the orbital implementation of the kinetic theory of stopping, in this work we present new results on the use of the Thomas-Fermi-Dirac-Weizsäcker density functional for the calculation of orbital and total atomic mean excitation energies. The results are applied to free-atoms and and extension is done to confined atoms - taking Si as an example - whereby target pressure effects on stopping are derived. Hence, evidence of the far-yield of Jens' ideas is given.

  2. Z1 dependence of ion-induced electron emission from aluminum

    International Nuclear Information System (INIS)

    Alonso, E.V.; Baragiola, R.A.; Ferron, J.; Jakas, M.M.; Oliva-Florio, A.

    1980-01-01

    We have measured the electron emission yields γ of clean aluminum under bombardment with H + , H 2 + , D + , D 2 + , He + , B + , C + , N + , N 2 + , O + , O 2 + , F + , Ne + , S + , Cl + , Ar + , Kr + , and Xe + in the energy range 1.2--50 keV. The clean surfaces were prepared by in situ evaporation of high-purity Al under ultra-high-vacuum conditions. It is found that kinetic electron emission yields γ/sub k/, obtained after subtracting from the measured γ a contribution due to potential emission, are roughly proportional to the electronic stopping powers, for projectiles lighter than Al. For heavier projectiles there is a sizable contribution to electron emission from collisions involving rapidly recoiling target atoms, which increases with the mass of the projectile, and which dominates the threshold and near-threshold behavior of kinetic emission. The results, together with recently reported data on Auger electron emission from ion-bombarded Al show that the mechanism proposed by Parilis and Kishinevskii of inner-shell excitation and subsequent Auger decay is negligible for light ions and probably small for heavy ions on Al and in our energy range. We thus conclude that kinetic electron emission under bombardment by low-energy ions results mainly from the escape of excited valence electrons

  3. Measurement of few-electron uranium ions on a high-energy electron beam ion trap

    International Nuclear Information System (INIS)

    Beiersdorfer, P.

    1994-01-01

    The high-energy electron beam ion trap, dubbed Super-EBIT, was used to produce, trap, and excite uranium ions as highly charged as fully stripped U 92+ . The production of such highly charged ions was indicated by the x-ray emission observed with high-purity Ge detectors. Moreover, high-resolution Bragg crystal spectromters were used to analyze the x-ray emission, including a detailed measurement of both the 2s 1/2 -2p 3/2 electric dipole and 2p 1/2 -2p 3/2 magnetic dipole transitions. Unlike in ion accelerators, where the uranium ions move at relativistic speeds, the ions in this trap are stationary. Thus very precise measurements of the transition energies could be made, and the QED contribution to the transition energies could be measured within less than 1 %. Details of the production of these highly charged ions and their measurement is given

  4. Electrostatic ion cyclotron waves and ion energy diffusion in a mirror machine

    International Nuclear Information System (INIS)

    Turner, W.C.

    1977-01-01

    Measurements of ion cyclotron fluctuations and ion energy diffusion in the neutral beam injected 2XIIB mirror machine are presented. A narrow band single mode spectrum is always observed. When the plasma is de-stabilized by turning off axially injected streaming plasma, the wave amplitude increases and a simultaneous increase in ion-energy diffusion is observed. The spectral properties of the wave do not change. The data are in accord with a wave particle saturation of the drift cyclotron loss cone (DCLC) mode

  5. Composition and energy spectrum variations of auroral ions

    International Nuclear Information System (INIS)

    Lynch, J.; Leach, R.; Pulliam, D.; Scherb, F.

    1977-01-01

    We have detected H + ,O + , and He ++ ions with E/q up to 20 keV/charge in a hydrogen aurora over Churchill, Manitoba, during the flight of a Javelin sounding rocket on February 11, 1975, We observed several examples of different types of ion events. One type consisted of bursts of H + and O + ions which arrived simultaneously at all energies within the range of the E/q analyzer. These events were apparently of local origin (distance + ions (O + /H + approximately-greater-than30%). A second type of event consisted of bursts of enhanced H + counting rates but no O + ions. The dispersion in time of the energy spectrum was consistent with an injection and acceleration site located at about 20 R/sub E/ from the earth. An enhancement of the He ++ counting rates was associated with these events, but the He ++ data are of limited statistical significance. A third type of event, consisting of short bursts of H + ions with wide energy spreads, was observed in association with an event in which the energy of the H + ions showed time dispersion. We interpret these short H + bursts as due to ions trapped in traveling waves generated by an explosive injection of plasma in the earth's magnetotail

  6. Measurement of ion energy by a calorimetric method

    Energy Technology Data Exchange (ETDEWEB)

    Mizuhashi, Kiyoshi; Tajima, Satoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Bunak, Suwat

    1996-12-01

    In calorimetric method, ion energy is determined based on the temperature changes during radiation of an absorbing material, radiation current and heat capacity of the calorimeter. This method is convenient and its measuring procedures are simple as well as the measuring apparatus. Here, the temperature changes of the calorimeter during {sup 14}N ion beam radiation were determined. The temperature increased linearly when irradiated with {sup 14}N{sup 3+}, 8.3 MeV or {sup 14}N{sup 2+}, 6 MeV, but not linearly for {sup 14}N{sup 1+}, 3.6 MeV, resulting in a comparatively large error. Thus, the measurement of ion energy by calorimetric method was found available as a convenient method for an accelerator having an energy stability less than 10{sup -3}. Especially this method seems to be useful for low-energy ion accelerator or ion injecting apparatus. (M.N.)

  7. Predicting rainfall erosivity by momentum and kinetic energy in Mediterranean environment

    Science.gov (United States)

    Carollo, Francesco G.; Ferro, Vito; Serio, Maria A.

    2018-05-01

    Rainfall erosivity is an index that describes the power of rainfall to cause soil erosion and it is used around the world for assessing and predicting soil loss on agricultural lands. Erosivity can be represented in terms of both rainfall momentum and kinetic energy, both calculated per unit time and area. Contrasting results on the representativeness of these two variables are available: some authors stated that momentum and kinetic energy are practically interchangeable in soil loss estimation while other found that kinetic energy is the most suitable expression of rainfall erosivity. The direct and continuous measurements of momentum and kinetic energy by a disdrometer allow also to establish a relationship with rainfall intensity at the study site. At first in this paper a comparison between the momentum-rainfall intensity relationships measured at Palermo and El Teularet by an optical disdrometer is presented. For a fixed rainfall intensity the measurements showed that the rainfall momentum values measured at the two experimental sites are not coincident. However both datasets presented a threshold value of rainfall intensity over which the rainfall momentum assumes a quasi-constant value. Then the reliability of a theoretically deduced relationship, linking momentum, rainfall intensity and median volume diameter, is positively verified using measured raindrop size distributions. An analysis to assess which variable, momentum or kinetic energy per unit area and time, is the best predictor of erosivity in Italy and Spain was also carried out. This investigation highlighted that the rainfall kinetic energy per unit area and time can be substituted by rainfall momentum as index for estimating the rainfall erosivity, and this result does not depend on the site where precipitation occurs. Finally, rainfall intensity measurements and soil loss data collected from the bare plots equipped at Sparacia experimental area were used to verify the reliability of some

  8. Kinetics and equilibrium studies for sorption of Cu (II) and Cr (VI) ions onto polymeric composite resins

    International Nuclear Information System (INIS)

    El-Zahhhar, A.A.; Abdel-Aziz, H.M.; Siyam, T.

    2005-01-01

    The sorption behavior of Cu (II) and Cr (VI) ions from aqueous solutions was studied using polymeric composite resins. Batch sorption experiments were performed as a function of hydrogen ion concentration, complexing agent concentration, resin weight and ionic strength. Kinetic parameters as a function of initial ion concentration were determined to predict the sorption behavior of Cu (II) and Cr (VI) onto polymeric composite resins. The equilibrium data could be fitted by the frendlich adsorption isotherm equation

  9. Conversion of magnetic energy to runaway kinetic energy during the termination of runaway current on the J-TEXT tokamak

    Science.gov (United States)

    Dai, A. J.; Chen, Z. Y.; Huang, D. W.; Tong, R. H.; Zhang, J.; Wei, Y. N.; Ma, T. K.; Wang, X. L.; Yang, H. Y.; Gao, H. L.; Pan, Y.; the J-TEXT Team

    2018-05-01

    A large number of runaway electrons (REs) with energies as high as several tens of mega-electron volt (MeV) may be generated during disruptions on a large-scale tokamak. The kinetic energy carried by REs is eventually deposited on the plasma-facing components, causing damage and posing a threat on the operation of the tokamak. The remaining magnetic energy following a thermal quench is significant on a large-scale tokamak. The conversion of magnetic energy to runaway kinetic energy will increase the threat of runaway electrons on the first wall. The magnetic energy dissipated inside the vacuum vessel (VV) equals the decrease of initial magnetic energy inside the VV plus the magnetic energy flowing into the VV during a disruption. Based on the estimated magnetic energy, the evolution of magnetic-kinetic energy conversion are analyzed through three periods in disruptions with a runaway current plateau.

  10. High-energy ion tail formation due to ion acoustic turbulence in the TRIAM-1 tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

    1982-02-01

    The two-component ion energy spectra observed in the TRIAM-1 tokamak are explained as a result of the high-energy ion tail formation due to ion acoustic turbulence driven by a toroidal current pulse for turbulent heating.

  11. Medium-energy ion reflection from solids

    CERN Document Server

    Mashkova, ES

    1985-01-01

    ``Medium-Energy Ion Reflection from Solids'' analyses the results of experimental, theoretical and computer investigations on the process of scattering of ions by solid surfaces. Surface scattering is a relatively young and rapidly developing branch of the physics of atomic collisions and the literature on this subject has rapidly grown.As the first monograph devoted specifically to surface scattering of ions, this book is directed at scientists involved in ion-solid interaction studies.

  12. Electrohydrodynamic emitters of ion beams

    International Nuclear Information System (INIS)

    Dudnikov, V.G.; Shabalin, A.L.

    1990-01-01

    Physical processes determining generation of ion beams with high emission current density in electrohydrodynamic emitters are considered. Electrohydrodynamic effects developing in ion emission features and kinetics of ion interaction in beams with high density are discussed. Factors determining the size of the emission zone, emission stability at high and low currents, cluster generation, increase of energy spread and decrease of brightness are analyzed. Problems on practical provision of stable EHD emitter functioning are considered. 94 refs.; 8 figs.; 1 tab

  13. The mechanism of diffusion and ionic transport of alkali metal ions in the particles of tin(IV) antimonate

    International Nuclear Information System (INIS)

    El-Naggar, I.M.; El-Absy, M.A.; Aly, S.I.; Atomic Energy Establishment, Cairo

    1992-01-01

    The kinetics of exchange Li + , Na + , K + and Cs + ions of tin(IV) antimonate with H + form was studied under particle-diffusion-control conditions at different temperatures. The value of activation energy, diffusion coefficient and entropy of activation increase with the ionic mobilities and radii, and decrease with the hydration energy of the alkali metal ions. On the basis of the kinetic parameters, the exchange of alkali metal ions occurs in the unhydrated form. (author). 29 refs.; 4 figs.; 2 tabs

  14. Stability and kinetics of uranyl ion complexation by macrocycles in propylene carbonate

    International Nuclear Information System (INIS)

    Fux, P.

    1984-06-01

    A thermodynamic study of uranyl ion complexes formation with different macrocyclic ligands was realized in propylene carbonate as solvent using spectrophotometric and potentiometric techniques. Formation kinetics of two UO 2 complexes: a crown ether (18C6) and a coronand (22) was studied by spectrophotometry in propylene carbonate with addition of tetraethylammonium chlorate 0.1M at 25 0 C. Possible structures of complexes in solution are discussed [fr

  15. Preliminary study on development of 300 Kv compact focused gaseous ion beam system

    Energy Technology Data Exchange (ETDEWEB)

    Ohkubo, T.; Ishii, Y.; Kamiya, T. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA) 1233 Watanuki-machi, Takasaki, Gunma, 370-1292 (Japan); Miyake, Y. [Beam Seiko Instruments Inc., 2-10-1 Kamata, Ohta-ku, Tokyo, 144-0052 (Japan)

    2013-04-19

    A new 300 kV compact focused gaseous ion beam (gas-FIB) system with three-stage acceleration lens was constructed at JAEA. The preliminary experiments of formation of the focused gaseous ion beams were carried out to show the availability of the gas-FIB system as a writing tool for 3D proton lithography. As a result of the experiments, it was proved that the focal point was kept at the same position under changing the kinetic energy but with keeping the kinetic energy ratio constant, which was defined as the ratio of kinetic energy in object side to that in image side for the third acceleration lens. This characteristic of the gas-FIB is a good point to advance the 3D proton lithography changing penetration depth in a sample by varying the beam energy.

  16. Preliminary study on development of 300 Kv compact focused gaseous ion beam system

    International Nuclear Information System (INIS)

    Ohkubo, T.; Ishii, Y.; Kamiya, T.; Miyake, Y.

    2013-01-01

    A new 300 kV compact focused gaseous ion beam (gas-FIB) system with three-stage acceleration lens was constructed at JAEA. The preliminary experiments of formation of the focused gaseous ion beams were carried out to show the availability of the gas-FIB system as a writing tool for 3D proton lithography. As a result of the experiments, it was proved that the focal point was kept at the same position under changing the kinetic energy but with keeping the kinetic energy ratio constant, which was defined as the ratio of kinetic energy in object side to that in image side for the third acceleration lens. This characteristic of the gas-FIB is a good point to advance the 3D proton lithography changing penetration depth in a sample by varying the beam energy.

  17. Kinetic-energy matrix elements for atomic Hylleraas-CI wave functions

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Frank E., E-mail: harris@qtp.ufl.edu [Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA and Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, Florida 32611 (United States)

    2016-05-28

    Hylleraas-CI is a superposition-of-configurations method in which each configuration is constructed from a Slater-type orbital (STO) product to which is appended (linearly) at most one interelectron distance r{sub ij}. Computations of the kinetic energy for atoms by this method have been difficult due to the lack of formulas expressing these matrix elements for general angular momentum in terms of overlap and potential-energy integrals. It is shown here that a strategic application of angular-momentum theory, including the use of vector spherical harmonics, enables the reduction of all atomic kinetic-energy integrals to overlap and potential-energy matrix elements. The new formulas are validated by showing that they yield correct results for a large number of integrals published by other investigators.

  18. The present state and perspectives of low-energy heavy ion biology

    International Nuclear Information System (INIS)

    Yuan Chengling; Yu Zengliang

    2004-01-01

    The interaction between low-energy ions and matter has been concerned rarely comparing to that of high-energy ions. It is even more unusual to find studies of the interaction of low-energy ions and complicated organisms. However, the discovery of bioeffects induced by ion beam implantation has opened a new branch in the field of ion beam applications in the life science--Low-energy Heavy Ion Biology. The mutagenic effect of low energy heavy ions was firstly reported in 1986 in rice. Since then, a damage mechanism involved in energy absorption, mass deposition, and charge exchange has been proposed. Accumulating evidence has indicated that these three factors are key determinants in the bioeffects induced by low energy heavy ions, which has opened new opportunities for mutational breeding, gene transferring, cell modification, and cell fusion. In recent years, the ion beam implantation technique has been widely applied in many fields, and increasing research interest in the field has been seen. The authors summarize recent advances in research on the role of low-energy ions in terms of the mechanisms and applications

  19. Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magentized Weakly Collisional Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Schekochihin, A. A.; Cowley, S. C.; Dorland, W.; Hammett, G. W.; Howes, G. G.; Quataert, E.; Tatsuno, T.

    2009-04-23

    This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulentmotions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated by these scales, the fully kinetic problem is systematically reduced to a more physically transparent and computationally tractable system of equations, which are derived in a rigorous way. In the "inertial range" above the ion gyroscale, the kinetic cascade separates into two parts: a cascade of Alfvenic fluctuations and a passive cascade of density and magnetic-fieldstrength fluctuations. The former are governed by the Reduced Magnetohydrodynamic (RMHD) equations at both the collisional and collisionless scales; the latter obey a linear kinetic equation along the (moving) field lines associated with the Alfvenic component (in the collisional limit, these compressive fluctuations

  20. Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magnetized Weakly Collisional Plasmas

    International Nuclear Information System (INIS)

    Schekochihin, A.A.; Cowley, S.C.; Dorland, W.; Hammett, G.W.; Howes, G.G.; Quataert, E.; Tatsuno, T.

    2009-01-01

    This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulent motions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated by these scales, the fully kinetic problem is systematically reduced to a more physically transparent and computationally tractable system of equations, which are derived in a rigorous way. In the 'inertial range' above the ion gyroscale, the kinetic cascade separates into two parts: a cascade of Alfvenic fluctuations and a passive cascade of density and magnetic-field strength fluctuations. The former are governed by the Reduced Magnetohydrodynamic (RMHD) equations at both the collisional and collisionless scales; the latter obey a linear kinetic equation along the (moving) field lines associated with the Alfvenic component (in the collisional limit, these compressive fluctuations

  1. Auger processes in tracks of fast multicharged ions

    International Nuclear Information System (INIS)

    Katin, V.V.; Martynenko, Yu.V.; Yavlinskij, Yu.N.

    1992-01-01

    The fast multicharged ion spends about 40% of energy losses on vacancy creation in the inner electron shells. This energy is transferred to the kinetic energy of electrons due to the cascade of Auger processes during ∼ 10 -14 s whereas the primary excited electrons receive the energy in ∼10 -16 s. (author)

  2. Kinetic energy spectra, vertical resolution and dissipation in high-resolution atmospheric simulations.

    Science.gov (United States)

    Skamarock, W. C.

    2017-12-01

    We have performed week-long full-physics simulations with the MPAS global model at 15 km cell spacing using vertical mesh spacings of 800, 400, 200 and 100 meters in the mid-troposphere through the mid-stratosphere. We find that the horizontal kinetic energy spectra in the upper troposphere and stratosphere does not converge with increasing vertical resolution until we reach 200 meter level spacing. Examination of the solutions indicates that significant inertia-gravity waves are not vertically resolved at the lower vertical resolutions. Diagnostics from the simulations indicate that the primary kinetic energy dissipation results from the vertical mixing within the PBL parameterization and from the gravity-wave drag parameterization, with smaller but significant contributions from damping in the vertical transport scheme and from the horizontal filters in the dynamical core. Most of the kinetic energy dissipation in the free atmosphere occurs within breaking mid-latitude baroclinic waves. We will briefly review these results and their implications for atmospheric model configuration and for atmospheric dynamics, specifically that related to the dynamics associated with the mesoscale kinetic energy spectrum.

  3. Nonequilibrium electron energy-loss kinetics in metal clusters

    CERN Document Server

    Guillon, C; Fatti, N D; Vallee, F

    2003-01-01

    Ultrafast energy exchanges of a non-Fermi electron gas with the lattice are investigated in silver clusters with sizes ranging from 4 to 26 nm using a femtosecond pump-probe technique. The results yield evidence for a cluster-size-dependent slowing down of the short-time energy losses of the electron gas when it is strongly athermal. A constant rate is eventually reached after a few hundred femtoseconds, consistent with the electron gas internal thermalization kinetics, this behaviour reflecting evolution from an individual to a collective electron-lattice type of coupling. The timescale of this transient regime is reduced in small nanoparticles, in agreement with speeding up of the electron-electron interactions with size reduction. The experimental results are in quantitative agreement with numerical simulations of the electron kinetics.

  4. Kinetic Energy from Supernova Feedback in High-resolution Galaxy Simulations

    Science.gov (United States)

    Simpson, Christine M.; Bryan, Greg L.; Hummels, Cameron; Ostriker, Jeremiah P.

    2015-08-01

    We describe a new method for adding a prescribed amount of kinetic energy to simulated gas modeled on a cartesian grid by directly altering grid cells’ mass and velocity in a distributed fashion. The method is explored in the context of supernova (SN) feedback in high-resolution (˜10 pc) hydrodynamic simulations of galaxy formation. Resolution dependence is a primary consideration in our application of the method, and simulations of isolated explosions (performed at different resolutions) motivate a resolution-dependent scaling for the injected fraction of kinetic energy that we apply in cosmological simulations of a 109 M⊙ dwarf halo. We find that in high-density media (≳50 cm-3) with coarse resolution (≳4 pc per cell), results are sensitive to the initial kinetic energy fraction due to early and rapid cooling. In our galaxy simulations, the deposition of small amounts of SN energy in kinetic form (as little as 1%) has a dramatic impact on the evolution of the system, resulting in an order-of-magnitude suppression of stellar mass. The overall behavior of the galaxy in the two highest resolution simulations we perform appears to converge. We discuss the resulting distribution of stellar metallicities, an observable sensitive to galactic wind properties, and find that while the new method demonstrates increased agreement with observed systems, significant discrepancies remain, likely due to simplistic assumptions that neglect contributions from SNe Ia and stellar winds.

  5. Neutron emission effects on final fragments mass and kinetic energy distribution from low energy fission of {sup 234}U

    Energy Technology Data Exchange (ETDEWEB)

    Montoya, M.; Rojas, J. [Instituto Peruano de Energia Nuclear, Av. Canada 1470, Lima 41 (Peru); Lobato, I. [Facultad de Ciencias, Universidad Nacional de Ingenieria, Av. Tupac Amaru 210, Apartado Postal 31-139, Lima (Peru)]. e-mail: mmontoya@ipen.gob.pe

    2008-07-01

    The standard deviation of the final kinetic energy distribution ({sigma}{sub e}) as a function of mass of final fragments (m) from low energy fission of {sup 234}U, measured with the Lohengrin spectrometer by Belhafaf et al., presents a peak around m = 109 and another around m = 122. The authors attribute the first peak to the evaporation of a large number of neutrons around the corresponding mass number, i.e. there is no peak on the standard deviation of the primary kinetic energy distribution ({sigma}{sub E}) as a function of primary fragment mass (A). The second peak is attributed to a real peak on {sigma}{sub E}(A). However, theoretical calculations related to primary distributions made by H.R. Faust and Z. Bao do not suggest any peak on {sigma}{sub E}(A). In order to clarify this apparent controversy, we have made a numerical experiment in which the masses and the kinetic energy of final fragments are calculated, assuming an initial distribution of the kinetic energy without structures on the standard deviation as function of fragment mass. As a result we obtain a pronounced peak on {sigma}{sub e} (m) curve around m = 109, a depletion from m = 121 to m = 129, and an small peak around m = 122, which is not as great as that measured by Belhafaf et al. Our simulation also reproduces the experimental results on the yield of the final mass Y(m), the average number of emitted neutrons as a function of the provisional mass (calculated from the values of the final kinetic energy of the complementary fragments) and the average value of fragment kinetic energy as a function of the final mass. From our results we conclude that there are no peaks on the {sigma}{sub E} (A) curve, and the observed peaks on {sigma}{sub e} (m) are due to the emitted neutron multiplicity and the variation of the average fragment kinetic energy as a function of primary fragment mass. (Author)

  6. 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

  7. Mixed moderate thermophilic bioleaching of Cu, Mo and Re from molybdenite concentrate: effects of silver ion, medium and energy sources

    Directory of Open Access Journals (Sweden)

    Hadi Abdollahi

    2017-12-01

    Full Text Available This study evaluates the effects of different additives such as silver ion, medium and energy sources on the efficiency of mixed moderate thermophilic bioleaching approach to extract Cu, Mo and Re from molybdenite concentrate containing 0.98% Cu, 1.56% Fe, 53.84% Mo, and 0.055% Re. Molybdenite was the major phase of Mo-bearing mineral and chalcopyrite, covellite and pyrite were distinguished as minor phases. The higher copper extraction was obtained in tests with silver additives in all types and quantities rather than tests without silver ion. Kinetic of copper dissolution varied in these experiments and depended on the types and amounts of silver, and other supplemented additives such as ferric ion. There was no clear difference in the copper extraction by various culture media and 100% of Cu was dissolved after 30 days of treatment, using 50 mg/L of silver nitrate as additives. In the best condition and without silver additives, maximum 60% of copper was extracted even in the presence of energy sources such as sulfur, ferrous and ferric ions. In the most effective test with initial pH 1.57, 50 mg/L silver nitrate, and 50 g/L ferric sulfate, 100% of copper was dissolved in less than a week with highest kinetics rate. Molybdenum and rhenium extraction had the same tends with redox potential graph. By increasing the redox potential to the 550-600mV, molybdenite started to dissolve and finally, molybdenum and rhenium were extracted 2% and 9.53% in the best condition; respectively.

  8. The prospect for fusion energy with light ions

    International Nuclear Information System (INIS)

    Mehlhorn, T.A.; Adams, R.G.; Bailey, J.E.

    1998-01-01

    Intense ion beams may be the best option for an Inertial Fusion Energy (IFE) driver. While light ions may be the long-term pulsed power approach to IFE, the current economic climate is such that there is no urgency in developing fusion energy sources. Research on light ion beams at Sandia will be suspended at the end of this fiscal year in favor of z-pinches studying ICF target physics, high yield fusion, and stewardship issues. The authors document the status of light ion research and the understanding of the feasibility of scaling light ions to IFE

  9. Noise and ac impedance analysis of ion transfer kinetics at the micro liquid/liquid interface

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Oksana; Holub, Karel; Mareček, Vladimír

    2015-01-01

    Roč. 56, JUL 2015 (2015), s. 43-45 ISSN 1388-2481 R&D Projects: GA ČR GA13-04630S Institutional support: RVO:61388955 Keywords : noise analysis * liquid/liquid interface * ion transfer kinetics Subject RIV: CG - Electrochemistry Impact factor: 4.569, year: 2015

  10. Fully stripped heavy ion yield vs energy for Xe and Au ions

    International Nuclear Information System (INIS)

    Thieberger, P.; Wegner, H.E.; Alonzo, J.; Gould, H.; Anholt, R.E.; Meyerhof, W.E.

    1985-01-01

    The Bevalac is now capable of accelerating U-238 ions to approximately 1 GeV/amu and measurements have shown that fully stripped U-238 ions are produced with good yield at these energies. However, knowing the stripping yields at different energies for U-238 does not allow an accurate prediction for other, lower Z projectiles. Consequently, extensive stripping yield measurements were made for Au-197 and Xe-139 ions. In addition to the stripping measurements from the direct Bevalac beam, pickup measurements were also made with specially prepared bare, one electron, and two electron ions. Since many research groups are considering heavy ion storage rings and/or synchrotrons, the pickup cross section for bare ions is important to estimate beam lifetime in terms of the average machine vacuum. Since the Mylar target provides a pickup probability similar to air, a preliminary analysis of the Xe 54+ and U 92+ data are presented along with predictions for other ions ranging down to Fe 26+ . 11 refs., 3 figs., 1 tab

  11. Fully stripped heavy ion yield vs energy for Xe and Au ions

    Energy Technology Data Exchange (ETDEWEB)

    Thieberger, P.; Wegner, H.E.; Alonzo, J.; Gould, H.; Anholt, R.E.; Meyerhof, W.E.

    1985-01-01

    The Bevalac is now capable of accelerating U-238 ions to approximately 1 GeV/amu and measurements have shown that fully stripped U-238 ions are produced with good yield at these energies. However, knowing the stripping yields at different energies for U-238 does not allow an accurate prediction for other, lower Z projectiles. Consequently, extensive stripping yield measurements were made for Au-197 and Xe-139 ions. In addition to the stripping measurements from the direct Bevalac beam, pickup measurements were also made with specially prepared bare, one electron, and two electron ions. Since many research groups are considering heavy ion storage rings and/or synchrotrons, the pickup cross section for bare ions is important to estimate beam lifetime in terms of the average machine vacuum. Since the Mylar target provides a pickup probability similar to air, a preliminary analysis of the Xe/sup 54 +/ and U/sup 92 +/ data are presented along with predictions for other ions ranging down to Fe/sup 26 +/. 11 refs., 3 figs., 1 tab.

  12. Ion Kinetics in the Solar Wind: Coupling Global Expansion to Local Microphysics

    Czech Academy of Sciences Publication Activity Database

    Matteini, L.; Hellinger, Petr; Landi, S.; Trávníček, Pavel M.; Velli, M.

    2012-01-01

    Roč. 172, 1-4 (2012), s. 373-396 ISSN 0038-6308 R&D Projects: GA AV ČR IAA300420702 Grant - others:ESA(XE) PECS 98068 Institutional research plan: CEZ:AV0Z30420517; CEZ:AV0Z10030501 Keywords : Solar wind * Ion kinetics * Numerical simulations Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 5.519, year: 2012 http://link.springer.com/article/10.1007%2Fs11214-011-9774-z#

  13. Kinetic Monte Carlo simulations compared with continuum models and experimental properties of pattern formation during ion beam sputtering

    International Nuclear Information System (INIS)

    Chason, E; Chan, W L

    2009-01-01

    Kinetic Monte Carlo simulations model the evolution of surfaces during low energy ion bombardment using atomic level mechanisms of defect formation, recombination and surface diffusion. Because the individual kinetic processes are completely determined, the resulting morphological evolution can be directly compared with continuum models based on the same mechanisms. We present results of simulations based on a curvature-dependent sputtering mechanism and diffusion of mobile surface defects. The results are compared with a continuum linear instability model based on the same physical processes. The model predictions are found to be in good agreement with the simulations for predicting the early-stage morphological evolution and the dependence on processing parameters such as the flux and temperature. This confirms that the continuum model provides a reasonable approximation of the surface evolution from multiple interacting surface defects using this model of sputtering. However, comparison with experiments indicates that there are many features of the surface evolution that do not agree with the continuum model or simulations, suggesting that additional mechanisms are required to explain the observed behavior.

  14. Kinetic description of a wiggler pumped ion-channel free electron laser

    International Nuclear Information System (INIS)

    Mehdian, H; Raghavi, A

    2006-01-01

    The wiggler pumped ion-channel free electron laser (WPIC-FEL) is treated and the classes of possible single-particle electron trajectories in this configuration are discussed in the paper. A new region of orbital stability is seen in the negative mass regime. A kinetic description of WPIC-FEL is given. Vlasov-Maxwell equations are solved to get the linear gain in a tenuous-beam limit, where the beam plasma frequency is much less than the radiation frequency and the self-field effects can be ignored

  15. Secondary electrons as probe of preequilibrium stopping power of ions penetrating solids

    International Nuclear Information System (INIS)

    Kroneberger, K.; Rothard, H.; Koschar, P.; Lorenzen, P.; Groeneveld, K.O.; Clouvas, A.; Veje, E.; Kemmler, J.

    1990-01-01

    The passage of ions through solid media is accompanied by the emission of low energy secondary electrons. At high ion velocities v p (i.e. v p > 10 7 cm/s) the kinetic emission of electrons as a result of direct Coulomb interaction between the ion and the target electron is the dominant initial production mechanism. The energy lost by the ion and, thus, transferred to the electrons is known as electronic stopping power in the solid. Elastic and inelastic interactions of primary, liberated electrons on their way through the bulk and the surface of the solid modify strongly their original energy and angular distribution and, in particular, leads to the transfer of their energy to further, i.e. secondary electrons (SE), such that the main part of the deposited energy of the ion is eventually over transferred to SE. It is, therefore, suggestive to assume a proportionality between the electronic stopping power S sm-bullet of the ion and the total SE yield g, i.e. the number of electrons ejected per ion. Following Sternglass the authors consider schematically for kinetic SE emission contributions from two extreme cases: (a) SEs produced mostly isotropically with large impact parameter, associated with an escape depth L SE from the solid; (b) SEs produced mostly unisotropically in forward direction with small impact parameter (δ-electrons), associated with a transport length L δ

  16. Imperfect Dark Energy from Kinetic Gravity Braiding

    CERN Document Server

    Deffayet, Cedric; Sawicki, Ignacy; Vikman, Alexander

    2010-01-01

    We introduce a large class of scalar-tensor models with interactions containing the second derivatives of the scalar field but not leading to additional degrees of freedom. These models exhibit peculiar features, such as an essential mixing of scalar and tensor kinetic terms, which we have named kinetic braiding. This braiding causes the scalar stress tensor to deviate from the perfect-fluid form. Cosmology in these models possesses a rich phenomenology, even in the limit where the scalar is an exact Goldstone boson. Generically, there are attractor solutions where the scalar monitors the behaviour of external matter. Because of the kinetic braiding, the position of the attractor depends both on the form of the Lagrangian and on the external energy density. The late-time asymptotic of these cosmologies is a de Sitter state. The scalar can exhibit phantom behaviour and is able to cross the phantom divide with neither ghosts nor gradient instabilities. These features provide a new class of models for Dark Energ...

  17. Nonlocal exchange and kinetic-energy density functionals for electronic systems

    International Nuclear Information System (INIS)

    Glossman, M.D.; Rubio, A.; Balbas, L.C.; Alonso, J.A.

    1992-01-01

    The nonlocal weighted density approximation (WDA) to the exchange and kinetic-energy functionals of many electron systems proposed several years ago by Alonso and Girifalco is used to compute, within the framework of density functional theory, the ground-state electronic density and total energy of noble gas atoms and of neutral jellium-like sodium clusters containing up to 500 atoms. These results are compared with analogous calculations using the well known Thomas-Fermi-Weizsacker-Dirac (TFWD) approximations for the kinetic (TFW) and exchange (D) energy density functionals. An outstanding improvement of the total and exchange energies, of the density at the nucleus and of the expectation values is obtained for atoms within the WDA scheme. For sodium clusters the authors notice a sizeable contribution of the nonlocal effects to the total energy and to the density profiles. In the limit of very large clusters these effects should affect the surface energy of the bulk metal

  18. Effect of high energy electrons on H{sup −} production and destruction in a high current DC negative ion source for cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Onai, M., E-mail: onai@ppl.appi.keio.ac.jp; Fujita, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Etoh, H.; Aoki, Y. [Sumitomo Heavy Industries, Ltd., Tokyo 141-6025 (Japan); Shibata, T. [High Energy Accelerator Research Organization (KEK), Ibaraki (Japan); Mattei, S.; Lettry, J. [CERN Rte de Meyrin, 1200 Geneva (Switzerland)

    2016-02-15

    Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H{sup −} production. The modelling results reasonably explains the dependence of the H{sup −} extraction current on the arc-discharge power in the experiments.

  19. Li-ion batteries: Phase transition

    International Nuclear Information System (INIS)

    Hou Peiyu; Zhang Yantao; Zhang Lianqi; Chu Geng; Gao Jian

    2016-01-01

    Progress in the research on phase transitions during Li + extraction/insertion processes in typical battery materials is summarized as examples to illustrate the significance of understanding phase transition phenomena in Li-ion batteries. Physical phenomena such as phase transitions (and resultant phase diagrams) are often observed in Li-ion battery research and already play an important role in promoting Li-ion battery technology. For example, the phase transitions during Li + insertion/extraction are highly relevant to the thermodynamics and kinetics of Li-ion batteries, and even physical characteristics such as specific energy, power density, volume variation, and safety-related properties. (topical review)

  20. Effective Remediation of Lead Ions from Aqueous Solution by Chemically Carbonized Rubber Wood Sawdust: Equilibrium, Kinetics, and Thermodynamic Study

    Directory of Open Access Journals (Sweden)

    Swarup Biswas

    2015-01-01

    Full Text Available Rubber wood sawdust was carbonized into charcoal by chemical treatment which was used for removal of lead ion from aqueous solution. The work involves batch experiments to investigate the pH effect, initial concentration of adsorbate, contact time, and adsorbent dose. Experimental data confirmed that the adsorption capacities increased with increasing inlet concentration and bed height and decreased with increasing flow rate. Adsorption results showed a maximum adsorption capacity of 37 mg/g at 308 K. Langmuir, Freundlich, and Temkin model adsorption isotherm models were applied to analyze the process where Temkin was found as a best fitted model for present study. Simultaneously kinetics of adsorption like pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were investigated. Thermodynamic parameters were used to analyze the adsorption experiment. Fourier transform infrared spectroscopy, scanning electron microscope, and energy dispersive X-ray spectroscopy confirmed the batch adsorption of lead ion onto chemically carbonized rubber wood sawdust.

  1. Improvement of the Energy Stability of the Single Ion Microbeam

    International Nuclear Information System (INIS)

    Zhan Furu; Qi Xuehong; Xu Mingliang; Chen Lianyun; Yu Zengliang

    2008-01-01

    Energy instability strongly affects the state and the beam size of the single ion microbeam. A facility based on the Generating Voltmeter was developed to improve the energy stability of the CAS-LIBB (Chinese Academy of Sciences, key laboratory of ion beam bioengineering) single ion microbeam. This paper presents the analysis of the energy instability of the single ion microbeam. A simplified theoretical model is set up to calculate the relationship between the energy instability and the beam spot size. By using this technique, the energy instability is adjusted to about 1%. Stable run-time is over 6 hours. The radius of the single ion beam is reduced by 10% compared to the previous one.

  2. Kinetic-energy induced smoothening and delay of epitaxial breakdown in pulsed-laser deposition

    International Nuclear Information System (INIS)

    Shin, Byungha; Aziz, Michael J.

    2007-01-01

    We have isolated the effect of kinetic energy of depositing species from the effect of flux pulsing during pulsed-laser deposition (PLD) on surface morphology evolution of Ge(001) homoepitaxy at low temperature (100 deg. C). Using a dual molecular beam epitaxy (MBE) PLD chamber, we compare morphology evolution from three different growth methods under identical experimental conditions except for the differing nature of the depositing flux: (a) PLD with average kinetic energy 300 eV (PLD-KE); (b) PLD with suppressed kinetic energy comparable to thermal evaporation energy (PLD-TH); and (c) MBE. The thicknesses at which epitaxial breakdown occurs are ranked in the order PLD-KE>MBE>PLD-TH; additionally, the surface is smoother in PLD-KE than in MBE. The surface roughness of the films grown by PLD-TH cannot be compared due to the early epitaxial breakdown. These results demonstrate convincingly that kinetic energy is more important than flux pulsing in the enhancement of epitaxial growth, i.e., the reduction in roughness and the delay of epitaxial breakdown

  3. WE-H-BRA-09: Application of a Modified Microdosimetric-Kinetic Model to Analyze Relative Biological Effectiveness of Ions Relevant to Light Ion Therapy Using the Particle Heavy Ion Transport System

    Energy Technology Data Exchange (ETDEWEB)

    Butkus, M [Yale-New Haven Hospital, New Haven, CT (United States); Palmer, T [Oregon State University, Corvallis, OR (United States)

    2016-06-15

    Purpose: To evaluate the dose and biological effectiveness of various ions that could potentially be used for actively scanned particle therapy. Methods: The PHITS Monte Carlo code paired with a microscopic analytical function was used to determine probability distribution functions of the lineal energy in 0.3µm diameter spheres throughout a water phantom. Twenty million primary particles for 1H beams and ten million particles for 4He, 7Li, 10B, 12C, 14N, 16O, and 20Ne were simulated for 0.6cm diameter pencil beams. Beam energies corresponding to Bragg peak depths of 50, 100, 150, 200, 250, and 300mm were used and evaluated transversely every millimeter and radially in annuli with outer radius of 1.0, 2.0, 3.0, 3.2, 3.4, 3.6, 4.0, 5.0, 10.0, 15.0, 20.0 and 25.0mm. The acquired probability distributions were reduced to dose-mean lineal energies and applied to the modified microdosimetric kinetic model for five different cell types to calculate relative biological effectiveness (RBE) compared to 60Co beams at the 10% survival threshold. The product of the calculated RBEs and the simulated physical dose was taken to create biological dose and comparisons were then made between the various ions. Results: Transversely, the 10B beam was seen to minimize relative biological dose in both the constant and accelerated dose change regions, proximal to the Bragg Peak, for all beams traveling greater than 50mm. For the 50mm beam, 7Li was seen to provide the most optimal biological dose profile. Radially small fluctuations (<4.2%) were seen in RBE while physical dose was greater than 1% for all beams. Conclusion: Even with the growing usage of 12C, it may not be the most optimal ion in all clinical situations. Boron was calculated to have slightly enhanced RBE characteristics, leading to lower relative biological doses.

  4. A Comparison of Kinetic Energy and Momentum in Special Relativity and Classical Mechanics

    Science.gov (United States)

    Riggs, Peter J.

    2016-01-01

    Kinetic energy and momentum are indispensable dynamical quantities in both the special theory of relativity and in classical mechanics. Although momentum and kinetic energy are central to understanding dynamics, the differences between their relativistic and classical notions have not always received adequate treatment in undergraduate teaching.…

  5. Scaling laws for simple heavy ion targets

    International Nuclear Information System (INIS)

    Gula, W.P.; Magelssen, G.R.

    1981-01-01

    We have examined the behavior of single shell DT gas filled spherical targets irradiated by a constant power heavy ion beam pulse. For targets in which the ion range is less than the shell thickness, our computational results suggest that the target can be divided into three regions: (1) the absorber (100 to 400 eV for the energies we have considered), (2) the cold pusher (a few eV), and (3) the DT gas fuel. We have examined the pusher collapse time, velocity, and maximum kinetic energy variations as functions of the various target parameters and ion beam energy. The results are expressed in analytic terms and verified by computer simulation

  6. Kinetic Study on the Sorption of Te (IV), Ce (III) and Eu (III) on some Inorganic Ion Exchangers

    International Nuclear Information System (INIS)

    El-Sweify, F.H.; Shehata, M.K.K.; El-Shazly, E.A.A.

    2008-01-01

    The sorption behaviour of Te (IV), Ce (III) and Eu (III) on zirconium phosphate (Zr P) and ceric tungstate under various conditions was studied. Some factors affecting the sorption kinetics of the aforementioned metal ions on both ion exchangers were investigated. These factors were: hydrogen ion concentration in the absence of complexing agents, contact time, particle size of the two mentioned ion exchangers, metal in concentration and temperature. Radioactive isotopes were used for tracing the corresponding elements. Some physical parameters related to the sorption process were calculated from the obtained data

  7. Kinetic studies of ICF target dynamics with ePLAS

    Science.gov (United States)

    Mason, R. J.

    2016-10-01

    The ePLAS code was recently used1 to show that a modeling change from artificial to real viscosity can result in a decrease of the predicted performance of ICF targets. This code typically follows either fluid or PIC electrons with fluid ions in self-consistent E - and B - fields computed by the Implicit Moment Method2. For the present study the ions have instead been run as PIC particles undergoing Krook-like self-collisions. The ePLAS collision model continually redistributes the ion particle properties toward a local Maxwellian, while conserving the mean density, momentum and energy. Whereas the use of real viscosity captures large Knudsen Number effects as the active target dimensions shrink below the ion mean-free-path, the new kinetic modeling can manifest additional effects such as collisional shock precursors3 from the escape and streaming of the fastest particle ions. In 2D cylindrical geometry we will explore how such kinetic shock extensions might affect shell and core compression dynamics in ICF target implosions.

  8. Ion beam generation at the plasma sheet boundary layer by kinetic Alfven waves

    International Nuclear Information System (INIS)

    Moghaddam-Taaheri, E.; Goertz, C.K.; Smith, R.A.

    1989-01-01

    The kinetic Alfven wave, an Alfven wave with a perpendicular wavelength comparable to the ion gyroradius, can diffuse ions both in velocity and coordinate spaces with comparable transport rates. This may lead to the generation of ion beams in the plasma sheet boundary layer (PSBL). To investigate the ion beam generation process numerically, a two-dimensional quasi-linear code was constructed. Assuming that the plasma β (the ratio of plasma pressure to the magnetic pressure) varies from β = 1 to β << 1 across the magnetic field, the dynamics of the ion beam generation in the PSBL was studied. It was found that if your start with an ion distribution function which monotonically decreases with velocity along the magnetic field and a density gradient across the magnetic field, ions diffuse in velocity-coordinate space until nearly a plateau is established along the diffusion path. Depending on the topology of the magnetic field at the lobe side of the simulation system, i.e., open or closed field lines, the ion distribution function may or may not reach a steady state. If the field lines are open there, i.e., if the diffusion extends into the lobe, the double diffusion process may provide a mechanism for continuously transferring the ions from the central plasma sheet to the lobe. The authors comment on the effect of the particle loss on the establishment of the pressure balance in the plasma sheet

  9. Aircraft Measurements of Atmospheric Kinetic Energy Spectra

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Lilly, D. K.

    1983-01-01

    Wind velocity data obtained from a jet airliner are used to construct kinetic energy spectra over the range of wavelengths from 2.5 to 2500 km. The spectra exhibit an approximate -5/3 slope for wavelengths of less than about 150 km, steepening to about -2.2 at larger scales. These results support...

  10. Numerical simulation and decomposition of kinetic energy in the Central Mediterranean: insight on mesoscale circulation and energy conversion

    Directory of Open Access Journals (Sweden)

    R. Sorgente

    2011-08-01

    Full Text Available The spatial and temporal variability of eddy and mean kinetic energy of the Central Mediterranean region has been investigated, from January 2008 to December 2010, by mean of a numerical simulation mainly to quantify the mesoscale dynamics and their relationships with physical forcing. In order to understand the energy redistribution processes, the baroclinic energy conversion has been analysed, suggesting hypotheses about the drivers of the mesoscale activity in this area. The ocean model used is based on the Princeton Ocean Model implemented at 1/32° horizontal resolution. Surface momentum and buoyancy fluxes are interactively computed by mean of standard bulk formulae using predicted model Sea Surface Temperature and atmospheric variables provided by the European Centre for Medium Range Weather Forecast operational analyses. At its lateral boundaries the model is one-way nested within the Mediterranean Forecasting System operational products.

    The model domain has been subdivided in four sub-regions: Sardinia channel and southern Tyrrhenian Sea, Sicily channel, eastern Tunisian shelf and Libyan Sea. Temporal evolution of eddy and mean kinetic energy has been analysed, on each of the four sub-regions, showing different behaviours. On annual scales and within the first 5 m depth, the eddy kinetic energy represents approximately the 60 % of the total kinetic energy over the whole domain, confirming the strong mesoscale nature of the surface current flows in this area. The analyses show that the model well reproduces the path and the temporal behaviour of the main known sub-basin circulation features. New mesoscale structures have been also identified, from numerical results and direct observations, for the first time as the Pantelleria Vortex and the Medina Gyre.

    The classical kinetic energy decomposition (eddy and mean allowed to depict and to quantify the permanent and fluctuating parts of the circulation in the region, and

  11. Nuclear structure studies with low-energy light ions: fundamental and applied

    International Nuclear Information System (INIS)

    Mazumdar, I.

    2016-01-01

    Studies in low and medium energy nuclear physics have been dominated by heavy-ion induced reactions for last five decades. Heavy-ion induced nuclear reactions have enriched our knowledge of the structural evolutions and intricacies of reaction dynamics of the nuclear many-body systems. However, the emergence and rise of heavy-ion physics have seen a general decline in studies with low- and medium-energy light-ion beams. The harsh reality of dwindling number of low-energy light ion facilities adversely affect research in nuclear physics. Very low-energy and high current light-ion facilities immediately conjures up in our minds the studies in nuclear astrophysics. Measurements of light-ion capture cross sections and astrophysical S factors are the major themes of research at most of the light-ion facilities. However, the importance low energy light-ion beams is multifarious. A variety of measurements providing vital support and inputs to heavy-ion research can only be carried out at the low-energy, light-ion facilities. Light-ion beams are also useful for generation of mono-energetic neutron beams. In this talk I will draw from some of our recent measurements to show the importance of light-ion beams in nuclear astrophysics and also in applied nuclear physics. (author)

  12. Discrete kinetic models from funneled energy landscape simulations.

    Directory of Open Access Journals (Sweden)

    Nicholas P Schafer

    Full Text Available A general method for facilitating the interpretation of computer simulations of protein folding with minimally frustrated energy landscapes is detailed and applied to a designed ankyrin repeat protein (4ANK. In the method, groups of residues are assigned to foldons and these foldons are used to map the conformational space of the protein onto a set of discrete macrobasins. The free energies of the individual macrobasins are then calculated, informing practical kinetic analysis. Two simple assumptions about the universality of the rate for downhill transitions between macrobasins and the natural local connectivity between macrobasins lead to a scheme for predicting overall folding and unfolding rates, generating chevron plots under varying thermodynamic conditions, and inferring dominant kinetic folding pathways. To illustrate the approach, free energies of macrobasins were calculated from biased simulations of a non-additive structure-based model using two structurally motivated foldon definitions at the full and half ankyrin repeat resolutions. The calculated chevrons have features consistent with those measured in stopped flow chemical denaturation experiments. The dominant inferred folding pathway has an "inside-out", nucleation-propagation like character.

  13. Mechanism of long-range penetration of low-energy ions in botanic samples

    International Nuclear Information System (INIS)

    Liu Feng; Wang Yugang; Xue Jianming; Wang Sixue; Du Guanghua; Yan Sha; Zhao Weijiang

    2002-01-01

    The authors present experimental evidence to reveal the mechanism of long-range penetration of low-energy ions in botanic samples. In the 100 keV Ar + ion transmission measurement, the result confirmed that low-energy ions could penetrate at least 60 μm thick kidney bean slices with the probability of about 1.0 x 10 -5 . The energy spectrum of 1 MeV He + ions penetrating botanic samples has shown that there is a peak of the count of ions with little energy loss. The probability of the low-energy ions penetrating the botanic sample is almost the same as that of the high-energy ions penetrating the same samples with little energy loss. The results indicate that there are some micro-regions with mass thickness less than the projectile range of low-energy ions in the botanic samples and they result in the long-range penetration of low-energy ions in botanic samples

  14. Channeling effect for low energy ion implantation in Si

    International Nuclear Information System (INIS)

    Cho, K.; Allen, W.R.; Finstad, T.G.; Chu, W.K.; Liu, J.; Wortman, J.J.

    1985-01-01

    Ion implantation is one of the most important processes in semiconductor device fabrication. Due to the crystalline nature of Si, channeling of implanted ions occurs during this process. Modern devices become smaller and shallower and therefore require ion implantation at lower energies. The effect of channeling on ion implantation becomes a significant problem for low energy ion implantation. The critical angle for axial and planar channeling increases with decreasing energy. This corresponds to an increased probability for channeling with lowering of ion energy. The industry approach to avoid the channeling problem is to employ a tilt angle of 7 0 between the ion implantation direction and the surface normal. We approach the problem by mapping major crystalline axes and planes near the [100] surface normal. Our analysis indicates that a 7 0 tilt is not an optimum selection in channeling reduction. Tilt angles in the range 5 0 to 6 0 combined with 7 0 +- 0.5 0 rotation from the (100) plane are better selections for the reduction of the channeling effect. The range of suitable angles is a function of the implantation energy. Implantations of boron along well specified crystallographic directions have been carried out by careful alignment and the resulting boron profiles measured by SIMS. (orig.)

  15. Balance of liquid-phase turbulence kinetic energy equation for bubble-train flow

    International Nuclear Information System (INIS)

    Ilic, Milica; Woerner, Martin; Cacuci, Dan Gabriel

    2004-01-01

    In this paper the investigation of bubble-induced turbulence using direct numerical simulation (DNS) of bubbly two-phase flow is reported. DNS computations are performed for a bubble-driven liquid motion induced by a regular train of ellipsoidal bubbles rising through an initially stagnant liquid within a plane vertical channel. DNS data are used to evaluate balance terms in the balance equation for the liquid phase turbulence kinetic energy. The evaluation comprises single-phase-like terms (diffusion, dissipation and production) as well as the interfacial term. Special emphasis is placed on the procedure for evaluation of interfacial quantities. Quantitative analysis of the balance equation for the liquid phase turbulence kinetic energy shows the importance of the interfacial term which is the only source term. The DNS results are further used to validate closure assumptions employed in modelling of the liquid phase turbulence kinetic energy transport in gas-liquid bubbly flows. In this context, the performance of respective closure relations in the transport equation for liquid turbulence kinetic energy within the two-phase k-ε and the two-phase k-l model is evaluated. (author)

  16. Ion distribution in the hot spot of an inertial confinement fusion plasma

    Science.gov (United States)

    Tang, Xianzhu; Guo, Zehua; Berk, Herb

    2012-10-01

    Maximizing the fusion gain of inertial confinement fusion (ICF) for inertial fusion energy (IFE) applications leads to the standard scenario of central hot spot ignition followed by propagating burn wave through the cold/dense assembled fuel. The fact that the hot spot is surrounded by cold but dense fuel layer introduces subtle plasma physics which requires a kinetic description. Here we perform Fokker-Planck calculations and kinetic PIC simulations for an ICF plasma initially in pressure balance but having large temperature gradient over a narrow transition layer. The loss of the fast ion tail from the hot spot, which is important for fusion reactivity, is quantified by Fokker-Planck models. The role of electron energy transport and the ambipolar electric field is investigated via kinetic simulations and the fluid moment models. The net effect on both hot spot ion temperature and the ion tail distribution, and hence the fusion reactivity, is elucidated.

  17. Rotational and divergent kinetic energy in the mesoscale model ALADIN

    Directory of Open Access Journals (Sweden)

    V. Blažica

    2013-03-01

    Full Text Available Kinetic energy spectra from the mesoscale numerical weather prediction (NWP model ALADIN with horizontal resolution 4.4 km are split into divergent and rotational components which are then compared at horizontal scales below 300 km and various vertical levels. It is shown that about 50% of kinetic energy in the free troposphere in ALADIN is divergent energy. The percentage increases towards 70% near the surface and in the upper troposphere towards 100 hPa. The maximal percentage of divergent energy is found at stratospheric levels around 100 hPa and at scales below 100 km which are not represented by the global models. At all levels, the divergent energy spectra are characterised by shallower slopes than the rotational energy spectra, and the difference increases as horizontal scales become larger. A very similar vertical distribution of divergent energy is obtained by using the standard ALADIN approach for the computation of spectra based on the extension zone and by applying detrending approach commonly used in mesoscale NWP community.

  18. Modification of structural chromosome mutations by zinc ions at wavelike kinetics of radiation mutagenesis in Crepis Capillaris seed cells

    International Nuclear Information System (INIS)

    Mustafaev, Kh. B.; Pomanov, V.P.

    1979-01-01

    The resting seeds Cr. capillaris have been irradiated by gamma rays in the 4 kR dose. Immediately after irradiation and within different terms of storage the seeds have been grown in the 3.5x10 -5 M solution ZnCl 2 and in the distilled water. Chromosome structural mutations in the K-mitosis of the first cell cycle have been studied. The frequency modification of chromosomal rearrangement by zinc ions at the waveline kinetics of the radiation mutagenesis is revealed as follows: zinc ions increase the mutation frequency at the points of waveline kinetics maximum and exert no influence at minimum points

  19. Mean excitation energies for molecular ions

    DEFF Research Database (Denmark)

    Jensen, Phillip W.K.; Sauer, Stephan P.A.; Oddershede, Jens

    2017-01-01

    The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase...

  20. Relationship between wave energy and free energy from pickup ions in the Comet Halley environment

    Science.gov (United States)

    Huddleston, D. E.; Johnstone, A. D.

    1992-01-01

    The free energy available from the implanted heavy ion population at Comet Halley is calculated by assuming that the initial unstable velocity space ring distribution of the ions evolves toward a bispherical shell. Ultimately this free energy adds to the turbulence in the solar wind. Upstream and downstream free energies are obtained separately for the conditions observed along the Giotto spacecraft trajectory. The results indicate that the waves are mostly upstream propagating in the solar wind frame. The total free energy density always exceeds the measured wave energy density because, as expected in the nonlinear process of ion scattering, the available energy is not all immediately released. An estimate of the amount which has been released can be obtained from the measured oxygen ion distributions and again it exceeds that observed. The theoretical analysis is extended to calculate the k spectrum of the cometary-ion-generated turbulence.

  1. Approach to kinetic energy density functionals: Nonlocal terms with the structure of the von Weizsaecker functional

    International Nuclear Information System (INIS)

    Garcia-Aldea, David; Alvarellos, J. E.

    2008-01-01

    We propose a kinetic energy density functional scheme with nonlocal terms based on the von Weizsaecker functional, instead of the more traditional approach where the nonlocal terms have the structure of the Thomas-Fermi functional. The proposed functionals recover the exact kinetic energy and reproduce the linear response function of homogeneous electron systems. In order to assess their quality, we have tested the total kinetic energies as well as the kinetic energy density for atoms. The results show that these nonlocal functionals give as good results as the most sophisticated functionals in the literature. The proposed scheme for constructing the functionals means a step ahead in the field of fully nonlocal kinetic energy functionals, because they are capable of giving better local behavior than the semilocal functionals, yielding at the same time accurate results for total kinetic energies. Moreover, the functionals enjoy the possibility of being evaluated as a single integral in momentum space if an adequate reference density is defined, and then quasilinear scaling for the computational cost can be achieved

  2. Kinetics of bromide catalysed oxidation of dextrose by cerium (IV) in aqueous sulphuric acid solution

    International Nuclear Information System (INIS)

    Sharma, J.; Sah, M.P.

    1994-01-01

    Kinetics of bromide catalysed oxidation of dextrose by Ce IV in aqueous sulphuric acid medium show first order dependence each in dextrose and cerium(IV). The reaction rate decreases on increasing the concentration of hydrogen ion. The increase in [HSO 4 - ] or [SO 4 2- ] decreases the rate. The bromide ion shows positive catalytic effect on the reaction rate. The value of activation energy has been calculated and a suitable mechanism confirming to the kinetic data is proposed. (author). 3 refs., 3 tabs

  3. High Energy Ion Acceleration by Extreme Laser Radiation Pressure

    Science.gov (United States)

    2017-03-14

    published in the internationally leading journal Physical Review Letters. We continued to progress this pionee 15.  SUBJECT TERMS ion therapy, heavy ion ...Thomson parabola spectrometer: To separate and provide a measurement of the charge -to-mass ratio and energy spectrum of the different ion species...AFRL-AFOSR-UK-TR-2017-0015 High energy ion acceleration by extreme laser radiation pressure Paul McKenna UNIVERSITY OF STRATHCLYDE VIZ ROYAL COLLEGE

  4. Enhancements to the Low-Energy Ion Facility at SUNY Geneseo

    Science.gov (United States)

    Barfield, Zachariah; Kostick, Steven; Nagasing, Ethan; Fletcher, Kurt; Padalino, Stephen

    2017-10-01

    The Low Energy Ion Facility at SUNY Geneseo is used for detector development and characterization for inertial confinement fusion diagnostics. The system has been upgraded to improve the ion beam quality by reducing contaminant ions. In the new configuration, ions produced by the Peabody Scientific duoplasmatron ion source are accelerated through a potential, focused into a new NEC analyzing magnet and directed to an angle of 30°. A new einzel lens on the output of the magnet chamber focuses the beam into a scattering chamber with a water-cooled target mount and rotatable detector mount plates. The analyzing magnet has been calibrated for deuteron, 4He+, and 4He2+ ion beams at a range of energies, and no significant hysteresis has been observed. The system can accelerate deuterons to energies up to 25 keV to initiate d-d fusion using a deuterated polymer target. Charged particle spectra with protons, tritons, and 3He ions from d-d fusion have been measured at scattering angles ranging from 55° to 135°. A time-of-flight beamline has been designed to measure the energies of ions elastically scattered at 135°. CEM detectors initiate start and stop signals from secondary electrons produced when low energy ions pass through very thin carbon foils. Funded in part by the U.S. Department of Energy through the Laboratory for Laser Energetics.

  5. ECR ion source for variable energy cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Bose, D K; Taki, G S; Nabhiraj, P Y; Pal, G; Dasgupta, B; Mallik, C; Das, S K; Bandopadhaya, D K; Bhandari, R K [Variable Energy Cyclotron Centre, Calcutta (India)

    1995-09-01

    Some performance characteristics of 6.4 GHz two stage ECR ion source which was under development at this centre is presented. The present ion source will facilitate acceleration of light heavy ions with the existing k=130 variable energy cyclotron. Multiply charged heavy ion (MCHI) beam from the source will also be utilized for atomic physics studies. Oxygen beam has already been used for ion implantation studies. The external injection system under development is nearing completion. Heavy ion beam from cyclotron is expected by end of 1995. (author).

  6. Turbulent kinetic energy balance measurements in the wake of a low-pressure turbine blade

    International Nuclear Information System (INIS)

    Sideridis, A.; Yakinthos, K.; Goulas, A.

    2011-01-01

    The turbulent kinetic energy budget in the wake generated by a high lift, low-pressure two-dimensional blade cascade of the T106 profile was investigated experimentally using hot-wire anemometry. The purpose of this study is to examine the transport mechanism of the turbulent kinetic energy and provide validation data for turbulence modeling. Point measurements were conducted on a high spatial resolution, two-dimensional grid that allowed precise derivative calculations. Positioning of the probe was achieved using a high accuracy traversing mechanism. The turbulent kinetic energy (TKE) convection, production, viscous diffusion and turbulent diffusion were all obtained directly from experimental measurements. Dissipation and pressure diffusion were calculated indirectly using techniques presented and validated by previous investigators. Results for all terms of the turbulent kinetic energy budget are presented and discussed in detail in the present work.

  7. Low energy implantation of boron with decaborane ions

    Science.gov (United States)

    Albano, Maria Angela

    The goal of this dissertation was to determine the feasibility of a novel approach to forming ultra shallow p-type junctions (tens of nm) needed for future generations of Si MOS devices. In the new approach, B dopant atoms are implanted by cluster ions obtained by ionization of decaborane (B 10H14) vapor. An experimental ion implanter with an electron impact ion source and magnetic mass separation was built at the Ion Beam and Thin Film Research Laboratory at NJIT. Beams of B10Hx+ ions with currents of a few microamperes and energies of 1 to 12 keV were obtained and used for implantation experiments. Profiles of B and H atoms implanted in Si were measured by Secondary Ion Mass Spectroscopy (SIMS) before and after rapid thermal annealing (RTA). From the profiles, the junction depth of 57 nm (at 1018 cm-3 B concentration) was obtained with 12 keV decaborane ions followed by RTA. The dose of B atoms that can be implanted at low energy into Si is limited by sputtering as the ion beam sputters both the matrix and the implanted atoms. As the number of sputtered B atoms increases with the implanted dose and approaches the number of the implanted atoms, equilibrium of B in Si is established. This effect was investigated by comparison of the B dose calculated from the ion beam integration with B content in the sample measured by Nuclear Reaction Analysis (NRA). Maximum (equilibrium) doses of 1.35 x 1016 B cm -2 and 2.67 x 1016 B cm-2 were obtained at the beam energies of 5 and 12 keV, respectively. The problem of forming shallow p-type junctions in Si is related not only to implantation depth, but also to transient enhanced diffusion (TED). TED in Si implanted with B10Hx+ was measured on boron doping superlattice (B-DSL) marker layers. It was found that TED, following decaborane implantation, is the same as with monomer B+ ion implantation of equivalent energy and that it decreases with the decreasing ion energy. (Abstract shortened by UMI.)

  8. Reflected and diffuse ions backstreaming from the earth's bow shock 1. Basic properties

    International Nuclear Information System (INIS)

    Bonifazi, C.; Moreno, G.

    1981-01-01

    Plasma data supplied by the ISEE 2 solar wind experiment are used to perform the first extended statistical analysis of the basic moments of the ions backstream from the earth's bow shock. The analysis is based on 3253 ion spectra, corresponding to a total observation time of approx. =87 hours. It turns out that the density and total energy density of the backstream ions are, on the average, equal to approx. =1% and approx. =10% of those of the solar wind, respectively. The distinction between the 'reflected' and 'diffuse' populations has been confirmed and put on a quantitive basis using the ratio A = V /sub B/P/w/sub B/P between the bulk velocity and the rms thermal speed of the ions. The reflected ions are characterized by a bulk velocity V/sub B/P of the order of 2 times the solar wind velocity and by a temperature of approx.7 x 10 6 K. In contrast, the diffuse ions have, on the average, a bulk velocity 1.2 times the solar wind velocity and a temperature of 40 x 10 6 K. Therefore the total energy density of the diffuse ions is approx. =30% larger than that of the reflected ions. Finally, the kinetic and thermal energy densities are distributed quite differently in the two ion populations: in fact, approx. =70% of the total energy density is kinetic for the reflected ions, while this percentage decreases to approx. =20% for the diffuse ions

  9. Counterstreaming ions as evidence of magnetic reconnection in the recovery phase of substorms at the kinetic level

    International Nuclear Information System (INIS)

    Nagai, Tsugunobu; Nakamura, Masao; Shinohara, Iku; Fujimoto, Masaki; Saito, Yoshifumi; Mukai, Toshifumi

    2002-01-01

    Counterstreaming ions embedded in hot isotropic ions are found at the front of fast earthward plasma flows in the recovery phase of substorms in the Earth's magnetotail. The counterstreaming ions are present only when the northward component of the magnetic field increases in the equatorial plane. Hybrid simulations of magnetic reconnection have been carried out. It is found that counterstreaming ions form in the leading edge of jetting plasmas produced with magnetic reconnection, where the magnetic field lines pile up due to the pre-existing stationary plasmas. These counterstreaming ions originate from cold ions on the northern and southern tail lobe field lines, and earthward transport of the reconnected field lines makes these cold ions flow into the equatorial plane. The present observations provide strong evidence of magnetic reconnection in the recovery phase of substorms at the kinetic level

  10. Turning an energy analyzer into a mass spectrometer and a charge sorter

    International Nuclear Information System (INIS)

    Lee, K.

    2004-01-01

    Full text:When a swarm of ions are accelerated by a pulsed electric field for a common duration before entering an electrostatically dispersive energy analyzer, they will be sorted according to their charge-to-mass ratio q/m. In other words, the apparent kinetic energy upon which an ion will be registered in an apparent 'energy' spectrum thus obtained is proportional to its q/m ratio. For ions of a fixed mass m, the apparent energy spectrum becomes a charge state distribution spectrum. For ions of a fixed charge q, the apparent energy spectrum becomes a mass spectrum. In essence, an energy analyzer becomes both a charge sorter and a mass spectrometer when operated in this mode. When this technique is brought to bear on the detection of photofragment ions, a distinct advantage emerges. Kinetic energy release distribution (KERD) of fragment ions conventionally is extracted from fitting of the ion time-of-flight profile to ion trajectory simulation results, as such a fair amount of uncertainty exists in the KERD thus obtained. With the current novel approach to mass spectrometry, the KERDs of photofragment ions can be obtained directly, and as a result, with a greater accuracy. This should advance the study of fragmentation dynamics considerably

  11. Implanting very low energy atomic ions into surface adsorbed cage molecules: the formation/emission of Cs/C60+

    International Nuclear Information System (INIS)

    Kolodney, Eli; Kaplan, Andrey; Manor, Yoni; Bekkerman, Anatoly; Tsipinyuk, Boris

    2004-01-01

    Full Text: We demonstrate the formation of an endo-complex via a collision of energetic ions with molecular overlayers on a surface. An incoming atomic ion is encapsulated inside a very large molecule or cluster by implanting the primary ion into the target species, which then recovers its original structure or rearrange itself around the implanted ion in some stable configuration. Here we describe an experiment resulting in the formation and ejection of an endo-complex, within a single collision. We study the formation and emission of endohedral fullerenes, Cs/C 60 + and Cs/C 70 + , following a single collision of Cs + ion with a sub-monolayer of C 60 (steady state coverage) on gold and silicon surfaces and with a sub-monolayer of C 70 on gold. A continuous low energy (E 0 =35-220 eV) Cs + ion beam hit the Cs + covered surface and the collisional formation and ejection of the endohedral Cs/Cs 60 + complex, within a single Cs + /C 60 collision was observed and characterized. Several experimental observations clearly demonstrate the single collision nature of the combined atom penetration endo-complex ejection event. The fullerene molecule is actually being picked up off the surface by the penetrating Cs + ion. The evidence for the trapping of the Cs + ion inside the fullerene cage is given both by the appearance of the Cs/Cs (602-2n) + (n=1-5) sequence and its termination at Cs/Cs 50 + . Kinetic Energy Distributions (KEDs) of the outgoing Cs/Cs 60 + were measured for two different Cs + impact energies under field-free conditions. The most striking observation is the near independence of the KEDs on the impact energy. Both KEDs peak around 1.2 eV with similar line shapes. A simple model for the formation/ejection/fragmentation dynamics of the endohedral complex is proposed and is found to be in good agreement with the experimental results

  12. Study of ion tracks by micro-probe ion energy loss spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Vacík, Jiří; Havránek, Vladimír; Hnatowicz, Vladimír; Horák, Pavel; Fink, Dietmar; Apel, P. Yu.

    2014-01-01

    Roč. 332, AUG (2014), s. 308-311 ISSN 0168-583X. [21st International Conference on Ion Beam Analysis (IBA). Seattle, 23.06.2013-28.06.2013] R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : ion energy loss spectrometry * single ion track * microprobe * tomography Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.124, year: 2014

  13. Biomaterial imaging with MeV-energy heavy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Toshio, E-mail: seki@sakura.nucleng.kyoto-u.ac.jp [Department of Nuclear Engineering, Kyoto Univ., Uji, Kyoto 611-0011 (Japan); CREST, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan); Wakamatsu, Yoshinobu; Nakagawa, Shunichiro [Department of Nuclear Engineering, Kyoto Univ., Uji, Kyoto 611-0011 (Japan); Aoki, Takaaki [Department of Electronic Science and Engineering, Kyoto Univ., Nishikyo, Kyoto 615-8510 (Japan); CREST, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan); Ishihara, Akihiko [Laboratory of Cell Biology and Life Science, Graduate School of Human and Environmental Studies, Kyoto Univ., Sakyo, Kyoto 606-8501 (Japan); Matsuo, Jiro [Quantum Science and Engineering Center, Kyoto Univ., Uji, Kyoto 611-0011 (Japan); CREST, Japan Science and Technology Agency (JST), Chiyoda, Tokyo 102-0075 (Japan)

    2014-08-01

    The spatial distribution of several chemical compounds in biological tissues and cells can be obtained with mass spectrometry imaging (MSI). In conventional secondary ion mass spectrometry (SIMS) with keV-energy ion beams, elastic collisions occur between projectiles and atoms of constituent molecules. The collisions produce fragments, making the acquisition of molecular information difficult. In contrast, ion beams with MeV-energy excite near-surface electrons and enhance the ionization of high-mass molecules; hence, SIMS spectra of fragment-suppressed ionized molecules can be obtained with MeV-SIMS. To compare between MeV and conventional SIMS, we used the two methods based on MeV and Bi{sub 3}-keV ions, respectively, to obtain molecular images of rat cerebellum. Conventional SIMS images of m/z 184 were clearly observed, but with the Bi{sub 3} ion, the distribution of the molecule with m/z 772.5 could be observed with much difficulty. This effect was attributed to the low secondary ion yields and we could not get many signal counts with keV-energy beam. On the other hand, intact molecular ion distributions of lipids were clearly observed with MeV-SIMS, although the mass of all lipid molecules was higher than 500 Da. The peaks of intact molecular ions in MeV-SIMS spectra allowed us to assign the mass. The high secondary ion sensitivity with MeV-energy heavy ions is very useful in biomaterial analysis.

  14. Biomaterial imaging with MeV-energy heavy ion beams

    International Nuclear Information System (INIS)

    Seki, Toshio; Wakamatsu, Yoshinobu; Nakagawa, Shunichiro; Aoki, Takaaki; Ishihara, Akihiko; Matsuo, Jiro

    2014-01-01

    The spatial distribution of several chemical compounds in biological tissues and cells can be obtained with mass spectrometry imaging (MSI). In conventional secondary ion mass spectrometry (SIMS) with keV-energy ion beams, elastic collisions occur between projectiles and atoms of constituent molecules. The collisions produce fragments, making the acquisition of molecular information difficult. In contrast, ion beams with MeV-energy excite near-surface electrons and enhance the ionization of high-mass molecules; hence, SIMS spectra of fragment-suppressed ionized molecules can be obtained with MeV-SIMS. To compare between MeV and conventional SIMS, we used the two methods based on MeV and Bi 3 -keV ions, respectively, to obtain molecular images of rat cerebellum. Conventional SIMS images of m/z 184 were clearly observed, but with the Bi 3 ion, the distribution of the molecule with m/z 772.5 could be observed with much difficulty. This effect was attributed to the low secondary ion yields and we could not get many signal counts with keV-energy beam. On the other hand, intact molecular ion distributions of lipids were clearly observed with MeV-SIMS, although the mass of all lipid molecules was higher than 500 Da. The peaks of intact molecular ions in MeV-SIMS spectra allowed us to assign the mass. The high secondary ion sensitivity with MeV-energy heavy ions is very useful in biomaterial analysis

  15. Kinetic Study on Channelling of Protons in Metallic Carbon Nanotubes

    International Nuclear Information System (INIS)

    Dan, Zhao; Yuan-Hong, Song; You-Nian, Wang

    2008-01-01

    Based on the kinetic model and the dielectric response theory, a theoretical model is put forward to describe the transport of protons along nanotube axes. With the introduction of electron band structure for different nanotubes like zigzag and armchair nanotubes of metallic properties, the collective excitation of electrons on the cylinders induced by the incident ions is studied, showing several distinct peaks in the curves of the energy loss function. Furthermore, the stopping power and the self-energy are calculated as functions of ion velocities, especially taking into account the influence of damping coefficients. It is conceivable from the results that, in the kinetic formulation, plasmon excitation plays a major role in the stopping. And as the damping increases, the peaks of the stopping power shift to the lower velocities, with the broadening of the plasmon resonance. (condensed matter: structure, mechanical and thermal properties)

  16. On the equipartition of kinetic energy in an ideal gas mixture

    International Nuclear Information System (INIS)

    Peliti, L

    2007-01-01

    A refinement of an argument due to Maxwell for the equipartition of translational kinetic energy in a mixture of ideal gases with different masses is proposed. The argument is elementary, yet it may work as an illustration of the role of symmetry and independence postulates in kinetic theory

  17. Ion temperature effects on magnetotail Alfvén wave propagation and electron energization: ION TEMPERATURE EFFECTS ON ALFVÉN WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Damiano, P. A. [Princeton Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton University, Princeton New Jersey USA; Johnson, J. R. [Princeton Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton University, Princeton New Jersey USA; Chaston, C. C. [Space Sciences Laboratory, University of California, Berkeley California USA; School of Physics, University of Sydney, Sydney New South Wales Australia

    2015-07-01

    A new 2-D self-consistent hybrid gyrofluid-kinetic electron model in dipolar coordinates is presented and used to simulate dispersive-scale Alfvén wave pulse propagation from the equator to the ionosphere along an L = 10 magnetic field line. The model is an extension of the hybrid MHD-kinetic electron model that incorporates ion Larmor radius corrections via the kinetic fluid model of Cheng and Johnson (1999). It is found that consideration of a realistic ion to electron temperature ratio decreases the propagation time of the wave from the plasma sheet to the ionosphere by several seconds relative to a ρi=0 case (which also implies shorter timing for a substorm onset signal) and leads to significant dispersion of wave energy perpendicular to the ambient magnetic field. Additionally, ion temperature effects reduce the parallel current and electron energization all along the field line for the same magnitude perpendicular electric field perturbation.

  18. Connecting the kinetics and energy landscape of tRNA translocation on the ribosome.

    Directory of Open Access Journals (Sweden)

    Paul C Whitford

    Full Text Available Functional rearrangements in biomolecular assemblies result from diffusion across an underlying energy landscape. While bulk kinetic measurements rely on discrete state-like approximations to the energy landscape, single-molecule methods can project the free energy onto specific coordinates. With measures of the diffusion, one may establish a quantitative bridge between state-like kinetic measurements and the continuous energy landscape. We used an all-atom molecular dynamics simulation of the 70S ribosome (2.1 million atoms; 1.3 microseconds to provide this bridge for specific conformational events associated with the process of tRNA translocation. Starting from a pre-translocation configuration, we identified sets of residues that collectively undergo rotary rearrangements implicated in ribosome function. Estimates of the diffusion coefficients along these collective coordinates for translocation were then used to interconvert between experimental rates and measures of the energy landscape. This analysis, in conjunction with previously reported experimental rates of translocation, provides an upper-bound estimate of the free-energy barriers associated with translocation. While this analysis was performed for a particular kinetic scheme of translocation, the quantitative framework is general and may be applied to energetic and kinetic descriptions that include any number of intermediates and transition states.

  19. Energy transfer and quenching processes of excited uranyl ion and lanthanide ions in solutions

    International Nuclear Information System (INIS)

    Yamamura, Tomoo; Tomiyasu, Hiroshi

    1995-01-01

    Deactivation processes of photoexcited uranyl ion by various lanthanide ions in aqueous solution were studied. Each lanthanide ions show different interaction with excited uranyl ion depending on its lowest excited energy level, the number of 4f electrons and the acid concentration of the solution. (author)

  20. Study on reaction mechanism by analysis of kinetic energy spectra of light particles and formation of final products

    Science.gov (United States)

    Giardina, G.; Mandaglio, G.; Nasirov, A. K.; Anastasi, A.; Curciarello, F.; Fazio, G.

    2018-05-01

    The sensitivity of reaction mechanism in the formation of compound nucleus (CN) by the analysis of kinetic energy spectra of light particles and of reaction products are shown. The dependence of the P CN fusion probability of reactants and W sur survival probability of CN against fission at its deexcitation on the mass and charge symmetries in the entrance channel of heavy-ion collisions, as well as on the neutron numbers is discussed. The possibility of conducting a complex program of investigations of the complete fusion by reliable ways depends on the detailed and refined methods of experimental and theoretical analyses.

  1. Linear kinetic stability of a field-reversed configuration with two ion components

    International Nuclear Information System (INIS)

    Staudenmeier, J.L.; Barnes, D.C.; Lewis, H.R.

    1990-01-01

    It has been suggested that a small fraction of non-axis encircling high energy ions may be sufficient to stabilize the tilt mode in a large s FRC. Experimental alteration of the ion distribution function in this manner might be achieved by rf heating the tail of the distribution function or by neutral beam injection. A linear Vlasov-fluid eigenfunction-eigenfrequency approach was used to investigate possible stabilization of the tilt mode by a high energy component. The ion distribution function is modeled as the sum of two Maxwellians with separate temperatures and no ion flow velocity. The cold component has a thermal s = 7, where s is the approximate number of ion gyroradii contained between the field null and the separatrix. The temperature ratio of the hot component to the cold component (T H /T T ) was varied from 2 to 100. Global hot particle fractions (n H ) up to ∼ .5 were used in the computations

  2. Energy distributions of an ion in a radio-frequency trap immersed in a buffer gas under the influence of additional external forces

    Science.gov (United States)

    Rouse, I.; Willitsch, S.

    2018-04-01

    An ion held in a radio-frequency trap interacting with a uniform buffer gas of neutral atoms develops a steady-state energy distribution characterized by a power-law tail at high energies instead of the exponential decay characteristic of thermal equilibrium. We have previously shown that the Tsallis statistics frequently used as an empirical model for this distribution is a good approximation when the ion is heated due to a combination of micromotion interruption and exchange of kinetic energy with the buffer gas [Rouse and Willitsch, Phys. Rev. Lett. 118, 143401 (2017), 10.1103/PhysRevLett.118.143401]. Here, we extend our treatment to include the heating due to additional motion of the ion caused by external forces, including the "excess micromotion" induced by uniform electric fields and rf phase offsets. We show that this also leads to a Tsallis distribution with a potentially different power-law exponent from that observed in the absence of this additional forced motion, with the difference increasing as the ratio of the mass of the neutral atoms to that of the ion decreases. Our results indicate that unless the excess micromotion is minimized to a very high degree, then even a system with very light neutrals and a heavy ion does not exhibit a thermal distribution.

  3. Intermediate energy proton and light-ion scattering

    International Nuclear Information System (INIS)

    Moss, J.M.

    1981-01-01

    A review is presented of recent (1979-81) developments in the field of intermediate-energy proton and light-ion scattering from nuclei. New theoretical and calculational techniques of particular interest to experimentalists are discussed. Emphasis is placed on topics in nuclear structure physics - giant resonances, pion-condensation precursor phenomena, and polarization transfer (spin-flip) experiments - where intermediate energy proton and light-ion scattering has made new and unique contributions

  4. Synchrotron-radiation experiments with recoil ions

    International Nuclear Information System (INIS)

    Levin, J.C.

    1989-01-01

    Studies of atoms, ions and molecules with synchrotron radiation have generally focused on measurements of properties of the electrons ejected during, or after, the photoionization process. Much can also be learned, however, about the atomic or molecular relaxation process by studies of the residual ions or molecular fragments following inner-shell photoionization. Measurements are reported of mean kinetic energies of highly charged argon, krypton, and xenon recoil ions produced by vacancy cascades following inner-shell photoionization using white and monochromatic synchrotron x radiation. Energies are much lower than for the same charge-state ions produced by charged-particle impact. The results may be applicable to design of future angle-resolved ion-atom collision experiments. Photoion charge distributions are presented and compared with other measurements and calculations. Related experiments with synchrotron-radiation produced recoil ion, including photoionization of stored ions and measurement of shakeoff in near-threshold excitation, are briefly discussed. 24 refs., 6 figs., 1 tab

  5. Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus

    International Nuclear Information System (INIS)

    Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A.

    2013-01-01

    The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy

  6. Renormalizing the Kinetic Energy Operator in Elementary Quantum Mechanics

    Science.gov (United States)

    Coutinho, F. A. B.; Amaku, M.

    2009-01-01

    In this paper, we consider solutions to the three-dimensional Schrodinger equation of the form [psi](r) = u(r)/r, where u(0) [is not equal to] 0. The expectation value of the kinetic energy operator for such wavefunctions diverges. We show that it is possible to introduce a potential energy with an expectation value that also diverges, exactly…

  7. Kinetic effects on magnetohydrodynamic phenomena

    International Nuclear Information System (INIS)

    Naito, Hiroshi; Matsumoto, Taro

    2001-01-01

    Resistive and ideal magnetohydrodynamic (MHD) theories are insufficient to adequately explain MHD phenomena in the high-temperature plasma. Recent progress in numerical simulations concerning kinetic effects on magnetohydrodynamic phenomena is summarized. The following three topics are studied using various models treating extended-MHD phenomena. (1) Kinetic modifications of internal kink modes in tokamaks with normal and reversed magnetic shear configurations. (2) Temporal evolution of the toroidal Alfven eigenmode and fishbone mode in tokamaks with energetic ions. (3) Kinetic stabilization of a title mode in field-reversed configurations by means of anchoring ions and beam ions. (author)

  8. Frequency-scanning MALDI linear ion trap mass spectrometer for large biomolecular ion detection.

    Science.gov (United States)

    Lu, I-Chung; Lin, Jung Lee; Lai, Szu-Hsueh; Chen, Chung-Hsuan

    2011-11-01

    This study presents the first report on the development of a matrix-assisted laser desorption ionization (MALDI) linear ion trap mass spectrometer for large biomolecular ion detection by frequency scan. We designed, installed, and tested this radio frequency (RF) scan linear ion trap mass spectrometer and its associated electronics to dramatically extend the mass region to be detected. The RF circuit can be adjusted from 300 to 10 kHz with a set of operation amplifiers. To trap the ions produced by MALDI, a high pressure of helium buffer gas was employed to quench extra kinetic energy of the heavy ions produced by MALDI. The successful detection of the singly charged secretory immunoglobulin A ions indicates that the detectable mass-to-charge ratio (m/z) of this system can reach ~385 000 or beyond.

  9. Review of intense-ion-beam propagation with a view toward measuring ion energy

    International Nuclear Information System (INIS)

    Garcia, M.

    1982-01-01

    The subject of this review is intense ion beam propagation and the possibilities of measuring time dependent ion energy in the beam. Propagation effects discussed include charge separation, charge and current autoneutralization, electron thermalization and current neutralization decay. The interaction of a plasma beam with material obstacles, like collimators, and with transverse magnetic fields is also described. Depending on beam energy, density and pulse length, these interactions can include material ablation with plasmadynamic flow and undeflected propagation across transverse magnetic fields by a polarization drift. On the basis of this review I conclude that three diagnostics: a single floating potential probe, net current probes (Faraday cups) and a Rutherford scattering spectrometer appear capable of giving prompt, time dependent ion energy measurements

  10. On the Equipartition of Kinetic Energy in an Ideal Gas Mixture

    Science.gov (United States)

    Peliti, L.

    2007-01-01

    A refinement of an argument due to Maxwell for the equipartition of translational kinetic energy in a mixture of ideal gases with different masses is proposed. The argument is elementary, yet it may work as an illustration of the role of symmetry and independence postulates in kinetic theory. (Contains 1 figure.)

  11. How Hot are Your Ions Really? A Threshold Collision-Induced Dissociation Study of Substituted Benzylpyridinium "Thermometer" Ions

    Science.gov (United States)

    Carpenter, John E.; McNary, Christopher P.; Furin, April; Sweeney, Andrew F.; Armentrout, P. B.

    2017-09-01

    The first absolute experimental bond dissociation energies (BDEs) for the main heterolytic bond cleavages of four benzylpyridinium "thermometer" ions are measured using threshold collision-induced dissociation in a guided ion beam tandem mass spectrometer. In this experiment, substituted benzylpyridinium ions are introduced into the apparatus using an electrospray ionization source, thermalized, and collided with Xe at varied kinetic energies to determine absolute cross-sections for these reactions. Various effects are accounted for, including kinetic shifts, multiple collisions, and internal and kinetic energy distributions. These experimentally measured 0 K BDEs are compared with computationally predicted values at the B3LYP-GD3BJ, M06-GD3, and MP2(full) levels of theory with a 6-311+G(2d,2p) basis set using vibrational frequencies and geometries determined at the B3LYP/6-311+G(d,p) level. Additional dissociation pathways are observed for nitrobenzylpyridinium experimentally and investigated using these same levels of theory. Experimental BDEs are also compared against values in the literature at the AM1, HF, B3LYP, B3P86, and CCSD(T) levels of theory. Of the calculated values obtained in this work, the MP2(full) level of theory with counterpoise corrections best reproduces the experimental results, as do the similar literature CCSD(T) values. Lastly, the survival yield method is used to determine the characteristic temperature (Tchar) of the electrospray source prior to the thermalization region and to confirm efficient thermalization. [Figure not available: see fulltext.

  12. Inertial confinement fusion systems using heavy ion accelerators as drivers

    International Nuclear Information System (INIS)

    Herrmannsfeldt, W.B.; Godlove, T.F.; Keefe, D.

    1980-03-01

    Heavy ion accelerators are the most recent entrants in the effort to identify a practical driver for inertial confinement fusion. They are of interest because of the expected efficient coupling of ion kinetic energy to the thermal energy needed to implode the pellet and because of the good electrical efficiency of high intensity particle accelerators. The beam intensities required, while formidable, lie within the range that can be studied by extensions of the theories and the technology of modern high energy accelerators

  13. 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

  14. Electronic stopping in ion-fullerene collisions

    NARCIS (Netherlands)

    Schlathölter, T.A.; Hadjar, O.; Hoekstra, R.A.; Morgenstern, R.W.H.

    The electronic friction experienced by a multiply charged ion interacting with the valence electrons of a single fullerene is an important aspect of the collision dynamics. It manifests itself in a considerable loss of projectile kinetic energy transferred to the target, resulting in excitation. The

  15. MEV Energy Electrostatic Accelerator Ion Beam Emittance Measurement

    OpenAIRE

    I.G. Ignat’ev; M.I. Zakharets; S.V. Kolinko; D.P. Shulha

    2014-01-01

    The testing equipment was designed, manufactured and tried out permitting measurements of total current, current profile and emittance of an ion beam extracted from the ion beam. MeV energy electrostatic accelerator ion H + beam emittance measurement results are presented.

  16. Low energy ion-molecule reaction dynamics and chemiionization kinetics: Progress report, February 1, 1985-January 31, 1988

    International Nuclear Information System (INIS)

    Farrar, J.M.

    1988-01-01

    The research program at Rochester is devoted to an understanding of the dynamics of elementary gas phase ionic reactions by using the molecular beam methods. We seek to elucidate pathways for energy disposal in elementary reactions, with the goal of using this information to understand the topology of the potential surfaces which govern the reaction, applying the results to ionic channels in combustion systems. We have made significant accomplishments in several distinct areas of research in crossed beam studies of ion-neutral reaction dynamics in the past three years. Our research has focused on the following topics and has resulted in 15 publications and submissions to major journals, with several additional manuscripts in preparation: dynamics of gas phase proton transfer reactions, gas phase carbon and methyl cation chemistry, reactive scattering from double minimum potentials, reactions of highly vibrationally excited ions: NH 3 + + D 2 , and electron and proton transfer reactions of anions. 9 refs

  17. A Capacity Fading Model of Lithium-Ion Battery Cycle Life Based on the Kinetics of Side Reactions for Electric Vehicle Applications

    International Nuclear Information System (INIS)

    Gu, Weijun; Sun, Zechang; Wei, Xuezhe; Dai, Haifeng

    2014-01-01

    Highlights: • Describe the aging mechanism of lithium-ion battery with electrochemical kinetics. • Establish the fading rate equation based on Eyring Equation. • The established equation is applicable to any reaction order. • Integrate the internal kinetics with external degradation characteristics. - Abstract: Battery life prediction is one of the critical issues that restrict the development of electric vehicles. Among the typical battery life models, the mechanism model focusing on the internal physical or electrochemical processes has a stronger theoretical foundation and greater accuracy. The empirical formula, which relies on the simplified mechanism, has a concise model structure and more flexibility in vehicle applications. However, the internal aging mechanism rarely correlates with the external operating characteristics. Based on the summary of the capacity fading mechanism and the reasoning of the internal kinetics of side reactions during the aging process, a lifetime model of the lithium-ion battery is established in this paper. The solutions to the vital parameters based on the external accelerated life testing results are also presented. The testing sample is a manganese oxide lithium-ion battery of 8 Ah. The validation results indicated that the life model established in this paper can describe the capacity fading law of the lithium-ion battery and the operability and accuracy for vehicle applications

  18. The interaction of low energy ion beams with surfaces

    International Nuclear Information System (INIS)

    Carter, G.; Armour, D.G.

    1981-01-01

    Four of the most important physical processes which occur during ion plating and allied techniques (1) ion-induced (and energetic-atom-induced) desorption of adsorbed impurities from the substrate surface, (2) ion penetration and entrapment in the substrate and coating, (3) ion-induced sputtering of substrate and coating atoms and (4) recoil displacement of substrate and coating atoms leading to their intermixing. The ion and energetic atom energy range of importance is from thermal energies to the order of 1keV. Current understanding of these processes, supported by discussion of available experimental data, is reviewed. (Auth.)

  19. Theory of kinetics and equilibrium of ion exchange-adsorption and mechanism of extracting uranium from sea-water with titanic gel

    International Nuclear Information System (INIS)

    Ai Hongtao

    1989-01-01

    An isothermal equation for ion exchange-adsorption is derived by mass action law. The equation can be used to sum up empirical and semiempirical formulas of the exchange adsorption, such as Gapon Equation, Sips Formula, Langmuir Equation and Freundlich Formula. In this paper, by adopting the ion exchange reaction to act as the determining step of the ion exchange adsorption kinetics, and exchange-adsorption kinetics equation is derived. It is verified by he results of a series of experiments in which uranium is extracted form enriched sea-water and natural sea-water with hydrous titanium oxide (titanic gel). This equation can be used to explain not only the results of test which have been applied to prove fast intraparticle diffusion of liquid film deffusion mechanism, but also test data which can be expalined by the co-controlling fast intraparticle and liquid film diffusion, and the kinetic data which can not be clarified by diffusion mechanism. It is proposed that the mechanism of the exchange adsorption of uranium from sea-water with titanic gel is a cationic exchange reaction. A method for calculating the quantity of exchange-adsorption at equilibrium is also given

  20. Rate theory of ion pairing at the water liquid-vapor interface: A case of sodium iodide

    Science.gov (United States)

    Dang, Liem X.; Schenter, Gregory K.

    2018-06-01

    Studies on ion pairing at interfaces have been intensified recently because of their importance in many chemical reactive phenomena, such as ion-ion interactions that are affected by interfaces and their influence on kinetic processes. In this study, we performed simulations to examine the thermodynamics and kinetics of small polarizable sodium iodide ions in the bulk and near the water liquid-vapor interface. Using classical transition state theory, we calculated the dissociation rates and corrected them with transmission coefficients obtained from the reactive flux formalism and Grote-Hynes theory. Our results show that in addition to affecting the free energy of ions in solution, the interfacial environments significantly influence the kinetics of ion pairing. The results on the relaxation time obtained using the reactive flux formalism and Grote-Hynes theory present an unequivocal picture that the interface suppresses ion dissociation. The effects of the use of molecular models on the ion interactions as well as the ion-pair configurations at the interface are also quantified and discussed.

  1. Collaborative Research: A Model of Partially Ionized Plasma Flows with Kinetic Treatment of Neutral Atoms and Nonthermal Ions

    International Nuclear Information System (INIS)

    Pogorelov, Nikolai; Zhang, Ming

    2016-01-01

    Interactions of flows of partially ionized, magnetized plasma are frequently accompanied by the presence of both thermal and non-thermal (pickup) ion components. Such interactions cannot be modeled using traditional MHD equations and require more advanced approaches to treat them. If a nonthermal component of ions is formed due to charge exchange and collisions between the thermal (core) ions and neutrals, it experiences the action of magnetic field, its distribution function is isotropized, and it soon acquires the velocity of the ambient plasma without being thermodynamically equilibrated. This situation, e. g., takes place in the outer heliosphere -- the part of interstellar space beyond the solar system whose properties are determined by the solar wind interaction with the local interstellar medium. This is also possible in laboratory, at million degrees and above, when plasma is conducting electricity far too well, which makes Ohmic heating ineffective. To attain the target temperatures one needs additional heating eventually playing a dominant role. Among such sources is a so-called neutral particle beam heating. This is a wide-spread technique (Joint European Torus and International Thermonuclear Experimental Reactor experiments) based on the injection of powerful beams of neutral atoms into ohmically preheated plasma. In this project we have investigated the energy and density separation between the thermal and nonthermal components in the solar wind and interstellar plasmas. A new model has been developed in which we solve the ideal MHD equations for mixture of all ions and the kinetic Boltzmann equation to describe the transport of neutral atoms. As a separate capability, we can treat the flow of neutral atoms in a multi-component fashion, where neutral atoms born in each thermodynamically distinct region are governed by the Euler gas dynamic equations. We also describe the behavior of pickup ions either kinetically, using the Fokker--Planck equation, or

  2. Collaborative Research: A Model of Partially Ionized Plasma Flows with Kinetic Treatment of Neutral Atoms and Nonthermal Ions

    Energy Technology Data Exchange (ETDEWEB)

    Pogorelov, Nikolai [Univ. of Alabama, Huntsville, AL (United States); Zhang, Ming [Florida Inst. of Technology, Melbourne, FL (United States)

    2016-07-31

    Interactions of flows of partially ionized, magnetized plasma are frequently accompanied by the presence of both thermal and non-thermal (pickup) ion components. Such interactions cannot be modeled using traditional MHD equations and require more advanced approaches to treat them. If a nonthermal component of ions is formed due to charge exchange and collisions between the thermal (core) ions and neutrals, it experiences the action of magnetic field, its distribution function is isotropized, and it soon acquires the velocity of the ambient plasma without being thermodynamically equilibrated. This situation, e. g., takes place in the outer heliosphere –- the part of interstellar space beyond the solar system whose properties are determined by the solar wind interaction with the local interstellar medium. This is also possible in laboratory, at million degrees and above, when plasma is conducting electricity far too well, which makes Ohmic heating ineffective. To attain the target temperatures one needs additional heating eventually playing a dominant role. Among such sources is a so-called neutral particle beam heating. This is a wide-spread technique (Joint European Torus and International Thermonuclear Experimental Reactor experiments) based on the injection of powerful beams of neutral atoms into ohmically preheated plasma. In this project we have investigated the energy and density separation between the thermal and nonthermal components in the solar wind and interstellar plasmas. A new model has been developed in which we solve the ideal MHD equations for mixture of all ions and the kinetic Boltzmann equation to describe the transport of neutral atoms. As a separate capability, we can treat the flow of neutral atoms in a multi-component fashion, where neutral atoms born in each thermodynamically distinct region are governed by the Euler gas dynamic equations. We also describe the behavior of pickup ions either kinetically, using the Fokker--Planck equation

  3. Collaborative Research: A Model of Partially Ionized Plasma Flows with Kinetic Treatment of Neutral Atoms and Nonthermal Ions

    Energy Technology Data Exchange (ETDEWEB)

    Pogorelov, Nikolai [Univ. of Alabama, Huntsville, AL (United States). Dept. of Space Science. Center for Space Plasma and; Zhang, Ming [Florida Inst. of Technology, Melbourne, FL (United States). Physics and Space Sciences Dept.; Borovikov, Sergey [Univ. of Alabama, Huntsville, AL (United States). Dept. of Space Science. Center for Space Plasma and Aeronomic Research; Heerikhuisen, Jacob [Univ. of Alabama, Huntsville, AL (United States). Dept. of Space Science. Center for Space Plasma and Aeronomic Research; Zank, Gary [Univ. of Alabama, Huntsville, AL (United States). Dept. of Space Science. Center for Space Plasma and Aeronomic Research; Gamayunov, Konstantin [Florida Inst. of Technology, Melbourne, FL (United States). Physics and Space Sciences Dept.; Colella, Phillip [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-07-31

    Interactions of flows of partially ionized, magnetized plasma are frequently accompanied by the presence of both thermal and non-thermal (pickup) ion components. Such interactions cannot be modeled using traditional MHD equations and require more advanced approaches to treat them. If a nonthermal component of ions is formed due to charge exchange and collisions between the thermal (core) ions and neutrals, it experiences the action of magnetic field, its distribution function is isotropized, and it soon acquires the velocity of the ambient plasma without being thermodynamically equilibrated. This situation, e. g., takes place in the outer heliosphere - the part of interstellar space beyond the solar system whose properties are determined by the solar wind interaction with the local interstellar medium. This is also possible in laboratory, at million degrees and above, when plasma is conducting electricity far too well, which makes Ohmic heating ineffective. To attain the target temperatures one needs additional heating eventually playing a dominant role. Among such sources is a so-called neutral particle beam heating. This is a wide-spread technique (Joint European Torus and International Thermonuclear Experimental Reactor experiments) based on the injection of powerful beams of neutral atoms into ohmically preheated plasma. In this project we have investigated the energy and density separation between the thermal and nonthermal components in the solar wind and interstellar plasmas. A new model has been developed in which we solve the ideal MHD equations for mixture of all ions and the kinetic Boltzmann equation to describe the transport of neutral atoms. As a separate capability, we can treat the flow of neutral atoms in a multi-component fashion, where neutral atoms born in each thermodynamically distinct regions are governed by the Euler gas dynamic equations. We also describe the behavior of pickup ions either kinetically, using the Fokker–Planck equation, or

  4. Kinetic transport in a magnetically confined and flux-constrained fusion plasma

    International Nuclear Information System (INIS)

    Darmet, G.

    2007-11-01

    This work deals with the kinetic transport in a fusion plasma magnetically confined and flux-constrained. The author proposes a new interpretation of the dynamics of zonal flows. The model that has been studied is a gyrokinetic model reduced to the transport of trapped ions. The inter-change stability that is generated allows the study of the kinetic transport of trapped ions. This model has a threshold instability and can be simulated over a few tens confining time for either thermal bath constraint or flux constraint. For thermal baths constraint, the simulation shows a metastable state where zonal flows are prevailing while turbulence is non-existent. In the case of a flux-constraint, zonal flows appear and relax by exchanging energy with system's kinetic energy and turbulence energy. The competition between zonal flows and turbulence can be then simulated by a predator-prey model. 2 regimes can be featured out: an improved confining regime where zonal flows dominate transport and a turbulent regime where zonal flows and turbulent transport are of the same magnitude order. We show that flux as well as the Reynolds tensor play an important role in the dynamics of the zonal flows and that the gyrokinetic description is relevant for all plasma regions. (A.C.)

  5. Fission Fragment Mass Distributions and Total Kinetic Energy Release of 235-Uranium and 238-Uranium in Neutron-Induced Fission at Intermediate and Fast Neutron Energies

    Energy Technology Data Exchange (ETDEWEB)

    Duke, Dana Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-12

    This Ph.D. dissertation describes a measurement of the change in mass distributions and average total kinetic energy (TKE) release with increasing incident neutron energy for fission of 235U and 238U. Although fission was discovered over seventy-five years ago, open questions remain about the physics of the fission process. The energy of the incident neutron, En, changes the division of energy release in the resulting fission fragments, however, the details of energy partitioning remain ambiguous because the nucleus is a many-body quantum system. Creating a full theoretical model is difficult and experimental data to validate existing models are lacking. Additional fission measurements will lead to higher-quality models of the fission process, therefore improving applications such as the development of next-generation nuclear reactors and defense. This work also paves the way for precision experiments such as the Time Projection Chamber (TPC) for fission cross section measurements and the Spectrometer for Ion Determination in Fission (SPIDER) for precision mass yields.

  6. Collisions of polyatomic ions with surfaces: incident energy partitioning and chemical reactions

    International Nuclear Information System (INIS)

    Zabka, J.; Roithova, J.; Dolejsek, Z.; Herman, Z.

    2002-01-01

    Collision of polyatomic ions with surfaces were investigated in ion-surface scattering experiments to obtain more information on energy partitioning in ion-surface collision and on chemical reactions at surfaces. Mass spectra, translation energy and angular distributions of product ions were measured in dependence on the incident energy and the incident angle of polyatomic projectiles. From these data distributions of energy fractions resulting in internal excitation of the projectile, translation energy of the product ions, and energy absorbed by the surface were determined. The surface investigated were a standard stainless steel surface, covered by hydrocarbons, carbon surfaces at room and elevated temperatures, and several surfaces covered by a self-assembled monolayers (C 12 -hydrocarbon SAM, C 11 -perfluorohydrocarbon SAM, and C 11 hydrocarbon with terminal -COOH group SAM). The main processes observed at collision energies of 10 - 50 eV were: neutralization of the ions at surfaces, inelastic scattering and dissociations of the projectile ions, quasi elastic scattering of the projectile ions, and chemical reactions with the surface material (usually hydrogen-atom transfer reactions). The ion survival factor was estimated to be a few percent for even-electron ions (like protonated ethanol ion, C 2 H 5 O + , CD 5 + ) and about 10 - 10 2 times lower for radical ions (like ethanol and benzene molecular ions, CD 4 + ). In the polyatomic ion -surface energy transfer experiments, the ethanol molecular ion was used as a well-characterized projectile ion. The results with most of the surfaces studied showed in the collision energy range of 13 - 32 eV that most collisions were strongly inelastic with about 6 - 8 % of the incident projectile energy transformed into internal excitation of the projectile (independent of the incident angle) and led partially to its further dissociation in a unimolecular way after the interaction with the surface. The incident energy

  7. Analysis of retarding field energy analyzer transmission by simulation of ion trajectories

    Science.gov (United States)

    van de Ven, T. H. M.; de Meijere, C. A.; van der Horst, R. M.; van Kampen, M.; Banine, V. Y.; Beckers, J.

    2018-04-01

    Retarding field energy analyzers (RFEAs) are used routinely for the measurement of ion energy distribution functions. By contrast, their ability to measure ion flux densities has been considered unreliable because of lack of knowledge about the effective transmission of the RFEA grids. In this work, we simulate the ion trajectories through a three-gridded RFEA using the simulation software SIMION. Using idealized test cases, it is shown that at high ion energy (i.e., >100 eV) the transmission is equal to the optical transmission rather than the product of the individual grid transparencies. Below 20 eV, ion trajectories are strongly influenced by the electric fields in between the grids. In this region, grid alignment and ion focusing effects contribute to fluctuations in transmission with ion energy. Subsequently the model has been used to simulate the transmission and energy resolution of an experimental RFEA probe. Grid misalignments reduce the transmission fluctuations at low energy. The model predicts the minimum energy resolution, which has been confirmed experimentally by irradiating the probe with a beam of ions with a small energy bandwidth.

  8. Direct conversion of fusion energy

    International Nuclear Information System (INIS)

    Johansson, Markus

    2003-03-01

    Deuterium and tritium are expected to be used as fuel in the first fusion reactors. Energy is released as kinetic energy of ions and neutrons, when deuterium reacts with tritium. One way to convert the kinetic energy to electrical energy, is to let the ions and neutrons hit the reactor wall and convert the heat that is caused by the particle bombardment to electrical energy with ordinary thermal conversion. If the kinetic energy of the ions instead is converted directly to electrical energy, a higher efficiency of the energy conversion is possible. The majority of the fusion energy is released as kinetic energy of neutrons, when deuterium reacts with tritium. Fusion reactions such as the D-D reactions, the D- 3 He reaction and the p- 11 B reaction, where a larger part of the fusion energy becomes kinetic energy of charged particles, appears therefore more suitable for direct conversion. Since they have lower reactivity than the D-T reaction, they need a larger βB 2 0 to give sufficiently high fusion power density. Because of this, the fusion configurations spherical torus (ST) and field-reversed configuration (FRC), where high β values are possible, appear interesting. Rosenbluth and Hinton come to the conclusion that efficient direct conversion isn't possible in closed field line systems and that open geometries, which facilitate direct conversion, provide inadequate confinement for D- 3 He. It is confirmed in this study that it doesn't seem possible to achieve as high direct conversion efficiency in closed systems as in open systems. ST and FRC fusion power plants that utilize direct conversion seem however interesting. Calculations with the help of Maple indicate that the reactor parameters needed for a D-D ST and a D 3 He ST hopefully are possible to achieve. The best energy conversion option for a D-D or D 3 He ST appears to be direct electrodynamic conversion (DEC) together with ordinary thermal conversion or liquid metal MHD conversion (LMMHD). For a D

  9. Direct conversion of fusion energy

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Markus

    2003-03-01

    Deuterium and tritium are expected to be used as fuel in the first fusion reactors. Energy is released as kinetic energy of ions and neutrons, when deuterium reacts with tritium. One way to convert the kinetic energy to electrical energy, is to let the ions and neutrons hit the reactor wall and convert the heat that is caused by the particle bombardment to electrical energy with ordinary thermal conversion. If the kinetic energy of the ions instead is converted directly to electrical energy, a higher efficiency of the energy conversion is possible. The majority of the fusion energy is released as kinetic energy of neutrons, when deuterium reacts with tritium. Fusion reactions such as the D-D reactions, the D-{sup 3}He reaction and the p-{sup 11}B reaction, where a larger part of the fusion energy becomes kinetic energy of charged particles, appears therefore more suitable for direct conversion. Since they have lower reactivity than the D-T reaction, they need a larger {beta}B{sup 2}{sub 0} to give sufficiently high fusion power density. Because of this, the fusion configurations spherical torus (ST) and field-reversed configuration (FRC), where high {beta} values are possible, appear interesting. Rosenbluth and Hinton come to the conclusion that efficient direct conversion isn't possible in closed field line systems and that open geometries, which facilitate direct conversion, provide inadequate confinement for D-{sup 3}He. It is confirmed in this study that it doesn't seem possible to achieve as high direct conversion efficiency in closed systems as in open systems. ST and FRC fusion power plants that utilize direct conversion seem however interesting. Calculations with the help of Maple indicate that the reactor parameters needed for a D-D ST and a D{sub 3} He ST hopefully are possible to achieve. The best energy conversion option for a D-D or D{sub 3} He ST appears to be direct electrodynamic conversion (DEC) together with ordinary thermal conversion

  10. Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Tso, Kin [Univ. of California, Berkeley, CA (United States)

    1996-05-01

    The 129Xe-induced reactions on natCu, 89Y, 165Ho, and 197Au at bombarding energies of E/A = 40 & 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the 129Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied.

  11. Prospects for high energy heavy ion accelerators

    International Nuclear Information System (INIS)

    Leemann, C.

    1979-03-01

    The acceleration of heavy ions to relativistic energies (T greater than or equal to 1 GeV/amu) at the beam intensities required for fundamental research falls clearly in the domain of synchrotons. Up to date, such beams have been obtained from machines originally designed as proton acccelerators by means of modified RF-programs, improved vacuum and, most importantly, altered or entirely new injector systems. Similarly, for the future, substantial changes in synchrotron design itself are not foreseen, but rather the judicious application and development of presently known principles and technologies and a choice of parameters optimized with respect to the peculiarities of heavy ions. The low charge to mass ratio, q/A, of very heavy ions demands that superconducting magnets be considered in the interest of the highest energies for a given machine size. Injector brightness will continue to be of highest importance, and although space charge effects such as tune shifts will be increased by a factor q 2 /A compared with protons, advances in linac current and brightness, rather than substantially higher energies are required to best utilize a given synchrotron acceptance. However, high yeilds of fully stripped, very heavy ions demand energies of a few hundred MeV/amu, thus indicating the need for a booster synchrotron, although for entirely different reasons than in proton facilities. Finally, should we consider colliding beams, the high charge of heavy ions will impose severe current limitations and put high demands on system design with regard to such quantities as e.g., wall impedances or the ion induced gas desorption rate, and advanced concepts such as low β insertions with suppressed dispersion and very small crossing angles will be essential to the achievement of useful luminosities

  12. Luminescence model with quantum impact parameter for low energy ions

    CERN Document Server

    Cruz-Galindo, H S; Martínez-Davalos, A; Belmont-Moreno, E; Galindo, S

    2002-01-01

    We have modified an analytical model of induced light production by energetic ions interacting in scintillating materials. The original model is based on the distribution of energy deposited by secondary electrons produced along the ion's track. The range of scattered electrons, and thus the energy distribution, depends on a classical impact parameter between the electron and the ion's track. The only adjustable parameter of the model is the quenching density rho sub q. The modification here presented, consists in proposing a quantum impact parameter that leads to a better fit of the model to the experimental data at low incident ion energies. The light output response of CsI(Tl) detectors to low energy ions (<3 MeV/A) is fitted with the modified model and comparison is made to the original model.

  13. Kinetics with deactivation of methylcyclohexane dehydrogenation for hydrogen energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Maria, G; Marin, A; Wyss, C; Mueller, S; Newson, E [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The methylcyclohexane dehydrogenation step to recycle toluene and release hydrogen is being studied as part of a hydrogen energy storage project. The reaction is performed catalytically in a fixed bed reactor, and the efficiency of this step significantly determines overall system economics. The fresh catalyst kinetics and the deactivation of the catalyst by coke play an important role in the process analysis. The main reaction kinetics were determined from isothermal experiments using a parameter sensitivity analysis for model discrimination. An activation energy for the main reaction of 220{+-}11 kJ/mol was obtained from a two-parameter model. From non-isothermal deactivation in PC-controlled integral reactors, an activation energy for deactivation of 160 kJ/mol was estimated. A model for catalyst coke content of 3-17 weight% was compared with experimental data. (author) 3 figs., 6 refs.

  14. Revisiting the density scaling of the non-interacting kinetic energy.

    Science.gov (United States)

    Borgoo, Alex; Teale, Andrew M; Tozer, David J

    2014-07-28

    Scaling relations play an important role in the understanding and development of approximate functionals in density functional theory. Recently, a number of these relationships have been redefined in terms of the Kohn-Sham orbitals [Calderín, Phys. Rev. A: At., Mol., Opt. Phys., 2013, 86, 032510]. For density scaling the author proposed a procedure involving a multiplicative scaling of the Kohn-Sham orbitals whilst keeping their occupation numbers fixed. In the present work, the differences between this scaling with fixed occupation numbers and that of previous studies, where the particle number change implied by the scaling was accommodated through the use of the grand canonical ensemble, are examined. We introduce the terms orbital and ensemble density scaling for these approaches, respectively. The natural ambiguity of the density scaling of the non-interacting kinetic energy functional is examined and the ancillary definitions implicit in each approach are highlighted and compared. As a consequence of these differences, Calderín recovered a homogeneity of degree 1 for the non-interacting kinetic energy functional under orbital scaling, contrasting recent work by the present authors [J. Chem. Phys., 2012, 136, 034101] where the functional was found to be inhomogeneous under ensemble density scaling. Furthermore, we show that the orbital scaling result follows directly from the linearity and the single-particle nature of the kinetic energy operator. The inhomogeneity of the non-interacting kinetic energy functional under ensemble density scaling can be quantified by defining an effective homogeneity. This quantity is shown to recover the homogeneity values for important approximate forms that are exact for limiting cases such as the uniform electron gas and one-electron systems. We argue that the ensemble density scaling provides more insight into the development of new functional forms.

  15. Measuring kinetic energy changes in the mesoscale with low acquisition rates

    Energy Technology Data Exchange (ETDEWEB)

    Roldán, É. [ICFO–Institut de Ciències Fotòniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain); GISC–Grupo Interdisciplinar de Sistemas Complejos, Madrid (Spain); Martínez, I. A.; Rica, R. A., E-mail: rul@ugr.es [ICFO–Institut de Ciències Fotòniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain); Dinis, L. [GISC–Grupo Interdisciplinar de Sistemas Complejos, Madrid (Spain); Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, 28040 Madrid (Spain)

    2014-06-09

    We report on the measurement of the average kinetic energy changes in isothermal and non-isothermal quasistatic processes in the mesoscale, realized with a Brownian particle trapped with optical tweezers. Our estimation of the kinetic energy change allows to access to the full energetic description of the Brownian particle. Kinetic energy estimates are obtained from measurements of the mean square velocity of the trapped bead sampled at frequencies several orders of magnitude smaller than the momentum relaxation frequency. The velocity is tuned applying a noisy electric field that modulates the amplitude of the fluctuations of the position and velocity of the Brownian particle, whose motion is equivalent to that of a particle in a higher temperature reservoir. Additionally, we show that the dependence of the variance of the time-averaged velocity on the sampling frequency can be used to quantify properties of the electrophoretic mobility of a charged colloid. Our method could be applied to detect temperature gradients in inhomogeneous media and to characterize the complete thermodynamics of biological motors and of artificial micro and nanoscopic heat engines.

  16. Closure of multi-fluid and kinetic equations for cyclotron-resonant interactions of solar wind ions with Alfvén waves

    Directory of Open Access Journals (Sweden)

    E. Marsch

    1998-01-01

    Full Text Available Based on quasilinear theory, a closure scheme for anisotropic multi-component fluid equations is developed for the wave-particle interactions of ions with electromagnetic Alfvén and ion-cyclotron waves propagating along the mean magnetic field. Acceleration and heating rates are calculated. They may be used in the multi-fluid momentum and energy equations as anomalous transport terms. The corresponding evolution equation for the average wave spectrum is established, and the effective growth/damping rate for the spectrum is calculated. Given a simple power-law spectrum, an anomalous collision frequency can be derived which depends on the slope and average intensity of the spectrum, and on the gyrofrequency and the differential motion (with respect to the wave frame of the actual ion species considered. The wave-particle interaction terms attain simple forms resembling the ones for collisional friction and temperature anisotropy relaxation (due to pitch angle scattering with collision rates that are proportional to the gyrofrequency but diminished substantially by the relative wave energy or the fluctuation level with respect the background field. In addition, a set of quasilinear diffusion equations is derived for the reduced (with respect to the perpendicular velocity component velocity distribution functions (VDFs, as they occur in the wave dispersion equation and the related dielectric function for parallel propagation. These reduced VDFs allow one to describe adequately the most prominent observed features, such as an ion beam and temperature anisotropy, in association with the resonant interactions of the particles with the waves on a kinetic level, yet have the advantage of being only dependent upon the parallel velocity component.

  17. Dependence of wavelength of Xe ion-induced rippled structures on the fluence in the medium ion energy range

    Energy Technology Data Exchange (ETDEWEB)

    Hanisch, Antje; Grenzer, Joerg [Institute of Ion Beam Physics and Materials Research, Dresden (Germany); Biermanns, Andreas; Pietsch, Ullrich [Institute of Physics, University of Siegen (Germany)

    2010-07-01

    Ion-beam eroded self-organized nanostructures on semiconductors offer new ways for the fabrication of high density memory and optoelectronic devices. It is known that wavelength and amplitude of noble gas ion-induced rippled structures tune with the ion energy and the fluence depending on the energy range, ion type and substrate. The linear theory by Makeev predicts a linear dependence of the ion energy on the wavelength for low temperatures. For Ar{sup +} and O{sub 2}{sup +} it was observed by different groups that the wavelength grows with increasing fluence after being constant up to an onset fluence and before saturation. In this coarsening regime power-law or exponential behavior of the wavelength with the fluence was monitored. So far, investigations for Xe ions on silicon surfaces mainly concentrated on energies below 1 keV. We found a linear dependence of both the ion energy and the fluence on the wavelength and amplitude of rippled structures over a wide range of the Xe{sup +} ion energy between 5 and 70 keV. Moreover, we estimated the ratio of wavelength to amplitude to be constant meaning a shape stability when a threshold fluence of 2.10{sup 17} cm{sup -2} was exceeded.

  18. Effects of an anode sheath on energy and momentum transfer in vacuum arcs

    International Nuclear Information System (INIS)

    Wang, Zhenxing; Zhou, Zhipeng; Tian, Yunbo; Wang, Haoran; Wang, Jianhua; Geng, Yingsan; Liu, Zhiyuan

    2017-01-01

    Anode phenomena under high-current vacuum arcs have a significant impact on the interrupting capacity of vacuum interrupters. However, the vacuum arc energy flux and momentum flux on the anode—which are necessary boundary conditions for simulations—are either set to an imaginary distribution or calculated using simple formulas without considering anode sheath regulatory effects. The objective of this paper is to reveal the anode sheath effects on regulating the energy and momentum transfer from the arc column to the anode surface in vacuum arcs. A particle-in-cell model for the anode sheath is developed. The required input parameters are obtained from a magnetohydrodynamic model for the arc column. From the results, there exists a sheath near the anode with a negative voltage drop. Both the electron density and the ion density significantly decline in the anode sheath region. The kinetic energy of the ions absorbed by the anode consists of directed kinetic energy, random kinetic energy, and sheath acceleration energy. The sheath acceleration energy contribution is the largest, and the random kinetic energy also accounts for a large part that cannot be ignored. The arc pressure on the anode surface is mainly caused by ion impact, and the accelerating effect of the anode sheath on the ions cannot be neglected in pressure calculations. In addition, in the case of an arc current at 15 kA, the input energy and momentum upon the anode surface is not obviously affected by the evaporated atoms at surface temperatures of 1600 K and 2000 K. (paper)

  19. Determination of kinetic coefficients for proton-nucleus collisions at high energy

    International Nuclear Information System (INIS)

    Rizzato, C.M.

    1987-01-01

    From the effective proton dynamics, the approximations in the context of high energy collisions which lead to the Boltzmann equation, are established. From this equation, general expressions for the kinetic coefficients are deduced. Using a simple model, analytical expressions for kinetic coefficients are obtained. The importance of the effect of Pauli blocking is also shown. (author) [pt

  20. Kinetic energy recovery systems in motor vehicles

    Science.gov (United States)

    Śliwiński, C.

    2016-09-01

    The article draws attention to the increasing environmental pollution caused by the development of vehicle transport and motorization. Different types of design solutions used in vehicles for the reduction of fuel consumption, and thereby emission of toxic gasses into the atmosphere, were specified. Historical design solutions concerning energy recovery devices in mechanical vehicles which used flywheels to accumulate kinetic energy were shown. Developmental tendencies in the area of vehicle manufacturing in the form of hybrid electric and electric devices were discussed. Furthermore, designs of energy recovery devices with electrical energy storage from the vehicle braking and shock absorbing systems were presented. A mechanical energy storing device using a flywheel operating under vacuum was presented, as were advantages and disadvantages of both systems, the limitations they impose on individual constructions and safety issues. The paper also discusses a design concept of an energy recovery device in mechanical vehicles which uses torsion springs as the main components of energy accumulation during braking. The desirability of a cooperation of both the mechanical- and electrical energy recovery devices was indicated.

  1. Inertial confinement fusion systems using heavy ion accelerators as drivers

    International Nuclear Information System (INIS)

    Herrmannsfeldt, W.B.; Godlove, T.F.; Keefe, D.

    1980-01-01

    Heavy ion accelerators are the most recent entrants in the effort to identify a practical driver for inertial confinement fusion. They are of interest because of the expected efficient coupling of ion kinetic energy to the thermal energy needed to implode the pellet and because of the good electrical efficiency of high intensity particle accelerators. The beam intensities required, while formidable, lie within the range that can be studied by extensions of the theories and the technology of modern high energy accelerators. (orig.) [de

  2. Experimental investigation of the formation of negative hydrogen ions in collisions between positive ions and atomic or molecular targets

    International Nuclear Information System (INIS)

    Lattouf, Elie

    2013-01-01

    The formation of the negative hydrogen ion (H - ) in collisions between a positive ion and a neutral atomic or molecular target is studied experimentally at impact energies of a few keV. The doubly-differential cross sections for H - formation are measured as a function of the kinetic energy and emission angle for the collision systems OH + + Ar and O + + H 2 O at 412 eV/a.m.u. These H - ions can be emitted at high energies (keV) in hard quasi-elastic two-body collisions involving a large momentum transfer to the H center. However, H - anions are preferentially emitted at low energy (eV) due to soft many-body (≥ 2) collisions resulting in a low momentum transfer. The formation of H - ions by electron capture follows excitation or ionization of the molecule. The molecular fragmentation dynamics is modeled to simulate the emission of H - ions. The overall good agreement between the simulation and the experiment leads to the understanding of most of the experimental observations. (author) [fr

  3. The mass angular scattering power method for determining the kinetic energies of clinical electron beams

    International Nuclear Information System (INIS)

    Blais, N.; Podgorsak, E.B.

    1992-01-01

    A method for determining the kinetic energy of clinical electron beams is described, based on the measurement in air of the spatial spread of a pencil electron beam which is produced from the broad clinical electron beam. As predicted by the Fermi-Eyges theory, the dose distribution measured in air on a plane, perpendicular to the incident direction of the initial pencil electron beam, is Gaussian. The square of its spatial spread is related to the mass angular scattering power which in turn is related to the kinetic energy of the electron beam. The measured spatial spread may thus be used to determine the mass angular scattering power, which is then used to determine the kinetic energy of the electron beam from the known relationship between mass angular scattering power and kinetic energy. Energies obtained with the mass angular scattering power method agree with those obtained with the electron range method. (author)

  4. Semi-local machine-learned kinetic energy density functional with third-order gradients of electron density

    Science.gov (United States)

    Seino, Junji; Kageyama, Ryo; Fujinami, Mikito; Ikabata, Yasuhiro; Nakai, Hiromi

    2018-06-01

    A semi-local kinetic energy density functional (KEDF) was constructed based on machine learning (ML). The present scheme adopts electron densities and their gradients up to third-order as the explanatory variables for ML and the Kohn-Sham (KS) kinetic energy density as the response variable in atoms and molecules. Numerical assessments of the present scheme were performed in atomic and molecular systems, including first- and second-period elements. The results of 37 conventional KEDFs with explicit formulae were also compared with those of the ML KEDF with an implicit formula. The inclusion of the higher order gradients reduces the deviation of the total kinetic energies from the KS calculations in a stepwise manner. Furthermore, our scheme with the third-order gradient resulted in the closest kinetic energies to the KS calculations out of the presented functionals.

  5. Ion-sound emission by Langmuir soliton reflected at density barrier

    International Nuclear Information System (INIS)

    El-Ashry, M.Y.

    1989-07-01

    The emission of ion-sound waves by an accelerated Langmuir soliton is studied. The acceleration of the soliton is due to an inhomogeneous density barrier. On the assumption that the kinetic energy of the Langmuir soliton is smaller than the potential energy created by the barrier. The basic equations describing the dynamic behaviour of the soliton and the emission of the ion-sound waves are formulated. The qualitative spatial distributions of the perturbed concentration in the ion-sound waves are analyzed at different characteristic points of the soliton. The energy lost by the soliton, as a result of the emission, is estimated. (author). 6 refs, 4 figs

  6. [Grain boundary and interface kinetics during ion irradiation

    International Nuclear Information System (INIS)

    Atwater, H.A.

    1991-01-01

    Proposed here is renewed support of a research program focused on interface motion and phase transformation during ion irradiation, with emphasis on elemental semiconductors. Broadly speaking, the aims of this program are to explore defect kinetics in amorphous and crystalline semiconductors, and to relate defect dynamics to interface motion and phase transformations. Over the last three years, we initiated a program under DOE support to explore crystallization and amorphization of elemental semiconductors under irradiation. This research has enabled new insights about the nature of defects in amorphous semiconductors and about microstructural evolution in the early stages of crystallization. In addition, we have demonstrated almost arbitrary control over the relative rates of crystal nucleation and crystal growth in silicon. As a result, the impinged grain microstructure of thin (100 nm) polycrystalline films crystallized under irradiation can be controlled with grain sizes ranging from a few nanometers to several micrometers, which may have interesting technological implications

  7. The eddy kinetic energy budget in the Red Sea

    KAUST Repository

    Zhan, Peng; Subramanian, Aneesh C.; Yao, Fengchao; Kartadikaria, Aditya R.; Guo, Daquan; Hoteit, Ibrahim

    2016-01-01

    The budget of eddy kinetic energy (EKE) in the Red Sea, including the sources, redistributions and sink, is examined using a high-resolution eddy-resolving ocean circulation model. A pronounced seasonally varying EKE is identified, with its maximum

  8. Importance of ion energy on SEU in CMOS SRAMs

    Energy Technology Data Exchange (ETDEWEB)

    Dodd, P.E.; Shaneyfelt, M.R.; Sexton, F.W.; Hash, G.L.; Winokur, P.S. [Sandia National Labs., Albuquerque, NM (United States); Musseau, O.; Leray, J.L. [CEA-DAM, Bruyeres-le-Chatel (France)

    1998-03-01

    The single-event upset (SEU) responses of 16 Kbit to 1 Mbit SRAMs irradiated with low and high-energy heavy ions are reported. Standard low-energy heavy ion tests appear to be sufficiently conservative for technologies down to 0.5 {micro}m.

  9. Low energy helium ion irradiation induced nanostructure formation on tungsten surface

    International Nuclear Information System (INIS)

    Al-Ajlony, A.; Tripathi, J.K.; Hassanein, A.

    2017-01-01

    We report on the low energy helium ion irradiation induced surface morphology changes on tungsten (W) surfaces under extreme conditions. Surface morphology changes on W surfaces were monitored as a function of helium ion energy (140–300 eV), fluence (2.3 × 10 24 –1.6 × 10 25 ions m −2 ), and flux (2.0 × 10 20 –5.5 × 10 20 ion m −2 s −1 ). All the experiments were performed at 900° C. Our study shows significant effect of all the three ion irradiation parameters (ion flux, fluence, and energy) on the surface morphology. However, the effect of ion flux is more pronounced. Variation of helium ion fluence allows to capture the very early stages of fuzz growth. The observed fuzz growth and morphology changes were understood in the realm of various possible phenomena. The study has relevance and important impact in the current and future nuclear fusion applications. - Highlights: •Reporting formation of W nanostructure (fuzz) due to low energy He ion beam irradiation. •Observing the very early stages for the W-Fuzz formation. •Tracking the surface morphological evolution during the He irradiation. •Discussing in depth our observation and drawing a possible scenario that explain this phenomenon. •Studying various ions irradiation parameters such as flux, fluence, and ions energy.

  10. The kinetic energy of the vortex and pinning force in high-temperature superconductors

    International Nuclear Information System (INIS)

    Boiko, J.; Khar'kovskij Gosudarstvennyj Univ.; Majewski, P.; Aldinger, F.

    1995-01-01

    It is known that the total magnetic energy of the vortex consists of two parts: the kinetic energy, E k , which is connected with the supercurrents which circulate around the vortex, and its own magnetic energy, E mo , which is connected with the real magnetic field. Therefore, the characteristic linear spacing which corresponds to the maximum change of the kinetic energy is not related with the magnetic penetration depth, λ, but with another characteristic spacing R. Considering this fact, the idea of the nature of F p of different defects which are greater than ξ, but smaller than λ, can be modified. (orig.)

  11. Spatial profile measurements of ion-confining potentials using novel position-sensitive ion-energy spectrometer arrays

    International Nuclear Information System (INIS)

    Yoshida, M.; Cho, T.; Hirata, M.; Ito, H.; Kohagura, J.; Yatsu, K.; Miyoshi, S.

    2003-01-01

    The first experimental demonstration of simultaneous measurements of temporally and spatially resolved ion-confining potentials phi c and end-loss-ion fluxes I ELA has been carried out during a single plasma discharge alone by the use of newly designed ion-energy-spectrometer arrays installed in both end regions of the GAMMA 10 tandem mirror. This position-sensitive ion-detector structure is proposed to obtain precise ion-energy spectra without any perturbations from simultaneously incident energetic electrons into the arrays. The relation between phi c and I ELA is physically interpreted in terms of Pastukhov's potential confinement theory. In particular, the importance of axisymmetric phi c formation is found for the plasma confinement

  12. Surface-Coating Regulated Lithiation Kinetics and Degradation in Silicon Nanowires for Lithium Ion Battery

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Langli; Yang, Hui; Yan, Pengfei; Travis, Jonathan J.; Lee, Younghee; Liu, Nian; Piper, Daniela M.; Lee, Se-Hee; Zhao, Peng; George, Steven M.; Zhang, Jiguang; Cui, Yi; Zhang, Sulin; Ban, Chunmei; Wang, Chong M.

    2015-05-26

    Silicon (Si)-based materials hold promise as the next-generation anodes for high-energy lithium (Li)-ion batteries. Enormous research efforts have been undertaken to mitigate the chemo-mechanical failure due to the large volume changes of Si during lithiation and delithiation cycles. It has been found nanostructured Si coated with carbon or other functional materials can lead to significantly improved cyclability. However, the underlying mechanism and comparative performance of different coatings remain poorly understood. Herein, using in situ transmission electron microscopy (TEM) through a nanoscale half-cell battery, in combination with chemo-mechanical simulation, we explored the effect of thin (~5 nm) alucone and Al2O3 coatings on the lithiation kinetics of Si nanowires (SiNWs). We observed that the alucone coating leads to a “V-shaped” lithiation front of the SiNWs , while the Al2O3 coating yields an “H-shaped” lithiation front. These observations indicate that the difference between the Li surface diffusivity and bulk diffusivity of the coatings dictates lithiation induced morphological evolution in the nanowires. Our experiments also indicate that the reaction rate in the coating layer can be the limiting step for lithiation and therefore critically influences the rate performance of the battery. Further, the failure mechanism of the Al2O3 coated SiNWs was also explored. Our studies shed light on the design of high capacity, high rate and long cycle life Li-ion batteries.

  13. In-situ kinetics of modifications induced by swift heavy ions in Al2O3: Colour centre formation, structural modification and amorphization

    International Nuclear Information System (INIS)

    Grygiel, C.; Moisy, F.; Sall, M.; Lebius, H.; Balanzat, E.; Madi, T.; Been, T.; Marie, D.; Monnet, I.

    2017-01-01

    This paper details in-situ studies of modifications induced by swift heavy ion irradiation in α-Al2O3. This complex behaviour is intermediary between the behaviour of amorphizable and non-amorphizable materials, respectively. A unique combination of irradiation experiments was performed at the IRRSUD beam line of the GANIL facility, with three different characterisation techniques: in-situ UV–Vis absorption, in-situ grazing incidence X-Ray diffraction and ex-situ transmission electron microscopy. This allows a complete study of point defects, and by depth profile of structural and microstructural modifications created on the trajectory of the incident ion. The α-Al2O3 crystals have been irradiated by 92 MeV Xenon and 74 MeV Krypton ions, the irradiation conditions have been chosen rather similar with an energy range where the ratio between electronic and nuclear stopping power changes dramatically as function of depth penetration. The main contribution of electronic excitation, above the threshold for track formation, is present beneath the surface to finally get almost only elastic collisions at the end of the projected range. Amorphization kinetics by the overlapping of multiple ion tracks is observed. In the crystalline matrix, long range strains, unit-cell swelling, local microstrain, domain size decrease, disordering of oxygen sublattice as well as colour centre formation are found. This study highlights the relationship between ion energy losses into a material and its response. While amorphization requires electronic stopping values above a certain threshold, point defects are predominantly induced by elastic collisions, while some structural modifications of the crystalline matrix, such as unit-cell swelling, are due to contribution of both electronic and nuclear processes.

  14. Energy reflection coefficient for H+ ions at energies between 10 and 80 keV

    International Nuclear Information System (INIS)

    Chen, C.K.; Bohdansky, J.; Eckstein, W.; Robinson, M.T.

    1984-04-01

    The energy reflection coefficient for H + ions at energies between 10 keV and 80 keV was determined by experiments and by computer calculations. Measurements were made with graphite, Al, Cu, Mo and W. targets. The angle of ion incidence was restricted to 85 0 , 78 0 and 70 0 measured from the surface normal. Calculated data were obtained by two different Monte Carlo computer programs (MARLOWE, TRIM). It was found that both the calculated and the measured data scale with the parameter epsilon cos 2 α, where epsilon is Lindhard's reduced energy and α the angle of incidence for the ions. The measured values are smaller than those calculated. This can be explained by surface roughness which developed during the ion irradiation

  15. Kinetics and hybrid kinetic-fluid models for nonequilibrium gas and plasmas

    International Nuclear Information System (INIS)

    Crouseilles, N.

    2004-12-01

    For a few decades, the application of the physics of plasmas has appeared in different fields like laser-matter interaction, astrophysics or thermonuclear fusion. In this thesis, we are interested in the modeling and the numerical study of nonequilibrium gas and plasmas. To describe such systems, two ways are usually used: the fluid description and the kinetic description. When we study a nonequilibrium system, fluid models are not sufficient and a kinetic description have to be used. However, solving a kinetic model requires the discretization of a large number of variables, which is quite expensive from a numerical point of view. The aim of this work is to propose a hybrid kinetic-fluid model thanks to a domain decomposition method in the velocity space. The derivation of the hybrid model is done in two different contexts: the rarefied gas context and the more complicated plasmas context. The derivation partly relies on Levermore's entropy minimization approach. The so-obtained model is then discretized and validated on various numerical test cases. In a second stage, a numerical study of a fully kinetic model is presented. A collisional plasma constituted of electrons and ions is considered through the Vlasov-Poisson-Fokker-Planck-Landau equation. Then, a numerical scheme which preserves total mass and total energy is presented. This discretization permits in particular a numerical study of the Landau damping. (author)

  16. Local kinetic-energy density of the Airy gas

    DEFF Research Database (Denmark)

    Vitos, Levente; Johansson, B.; Kollár, J.

    2000-01-01

    The Airy gas model is used to derive an expression for the local kinetic energy in the linear potential approximation. The expression contains an explicit Laplacian term 2/5((h) over bar(2)/2m)del(mu)(2)(r) that, according to jellium surface calculations, must be a universal feature of any accura...

  17. Effect of energy selection on quantitative analysis in secondary ion microanalysis

    International Nuclear Information System (INIS)

    Steele, I.M.; Solberg, T.N.; Smith, J.V.; Clayton, R.N.; Hutcheon, I.D.

    1977-01-01

    Systematic change of voltage on the components of the secondary ion (SI) extraction system of our AEI-IM20 ion microprobe produced major changes of relative intensities of secondary ions passing through the mass spectrometer. The repeller, which bends the SI beam through about 60 0 , has the greatest effect, and can be used to plot the energy distribution. The extractor and the deflecting and focusing components have smaller but significant effects. Because low-energy secondary ions have a near-symmetrical distribution, whereas high-energy ones have an assymetric distribution favoring high energies, tuning of the acceptance band to higher energy reduces interference from low-energy ions, which tend to be unwanted molecular ions, at the expense of reduced transmission. Tuning to lower energy increases interference but gives higher transmission. The former condition is desirable for instruments restricted to low mass resolution, whereas both conditions are valuable for instruments adjustable for both high and low mass resolution. Other important factors are (a) sensitivity to surface irregularities which perturb SI energy collection, and (b) change in derived 'temperatures' from thermodynamic sputtering models merely from tuning the energy acceptance band. Careful attention to the above factors yielded reproducible SI ratios for the binary series of plagioclase feldspars. (Auth.)

  18. Kinetics of hydroxyapatite deposition on solid substrates modified by sequential implantation of Ca and P ions - Part I. FTIR and Raman spectroscopy study

    Science.gov (United States)

    Pecheva, Emilia V.; Pramatarova, Liliana D.; Maitz, Manfred F.; Pham, Mihn T.; Kondyuirin, Alexey V.

    2004-07-01

    In this work, the kinetics of hydroxyapatite (HA) deposition on solid substrates from liquid precursor (simulated body fluid, SBF) is investigated. The surfaces of stainless steel, silicon and silica glass substrates are modified by sequential implantation of Ca and P ions. Three groups of samples of each material: (i) ion-implanted; (ii) ion-implanted and thermally treated at 873 K in air for 60 min; and (iii) untreated are prepared. To investigate the kinetics of the HA deposition, all three groups of samples are introduced at equal conditions into SBF whose supersaturation is maintained during the whole 6-day period of immersion. The layers are analyzed by FTIR and Raman spectroscopy. Both techniques complement each other and show the formation of HA with incorporated CO 32- and HPO 42- groups. Following the kinetics of the deposition process, it is concluded that the speed of deposition is different on the three materials modified by Ca and P implantation and by oxidation, compared to untreated samples but in order to distinguish clearly the effect of the ion implantation and oxidation the very initial moment of nucleation and layer growth should be more carefully investigated.

  19. Fundamental aspects of plasma chemical physics kinetics

    CERN Document Server

    Capitelli, Mario; Colonna, Gianpiero; Esposito, Fabrizio; Gorse, Claudine; Hassouni, Khaled; Laricchiuta, Annarita; Longo, Savino

    2016-01-01

    Describing non-equilibrium "cold" plasmas through a chemical physics approach, this book uses the state-to-state plasma kinetics, which considers each internal state as a new species with its own cross sections. Extended atomic and molecular master equations are coupled with Boltzmann and Monte Carlo methods to solve the electron energy distribution function. Selected examples in different applied fields, such as microelectronics, fusion, and aerospace, are presented and discussed including the self-consistent kinetics in RF parallel plate reactors, the optimization of negative ion sources and the expansion of high enthalpy flows through nozzles of different geometries. The book will cover the main aspects of the state-to-state kinetic approach for the description of nonequilibrium cold plasmas, illustrating the more recent achievements in the development of kinetic models including the self-consistent coupling of master equations and Boltzmann equation for electron dynamics. To give a complete portrayal, the...

  20. Isotopic exchange kinetics of zinc ions in Zn-A zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Radak, V M; Gal, I J; Salai, J J [Belgrade Univ. (Yugoslavia)

    1976-01-01

    The isotopic exchange kinetics of Zn/sup 2 +/ ions in hydrated Zn-A zeolite of composition (Znsub(5.55)Nasub(0.90)(A10/sub 2/)/sub 12/(Si0/sub 2/)/sub 12/.aq) have been investigated by measuring the fractional attainment of isotopic equilibrium between a ZnCl/sub 2/ solution and a /sup 65/Zn-labelled Zn-A zeolite (30 and 45 ..mu..m particle radii) as a function of time, in the temperature range 25 to 60/sup 0/C. The exchange mechanism is a two-step process which has been resolved, using the Brown-Sherry-Krambeck model (J.Phys.Chem.;75:3846(1971)) into diffusion in the solid particles, with Zn/sup 2 +/ diffusivity of D = 10sup(-3.97 + -0.03) exp(-Esub(D)/RT)m/sup 2/ s/sup -1/, Esub(D) = 67.1 +- 0.5 kJ molee/sup -1/, and an intracrystalline first-order exchange between bound and mobile Zn/sup 2 +/ ions in the network, with a rate constant of k/sub 2/ = 10sup(3.05 +- 0.25) exp(-Esub(k)/RT)s/sup -1/, Esub(k) = 56.5 +- 1.5 kJ mol/sup -1/.

  1. Highly Compressed Ion Beams for High Energy Density Science

    CERN Document Server

    Friedman, Alex; Briggs, Richard J; Callahan, Debra; Caporaso, George; Celata, C M; Davidson, Ronald C; Faltens, Andy; Grant-Logan, B; Grisham, Larry; Grote, D P; Henestroza, Enrique; Kaganovich, Igor D; Lee, Edward; Lee, Richard; Leitner, Matthaeus; Nelson, Scott D; Olson, Craig; Penn, Gregory; Reginato, Lou; Renk, Tim; Rose, David; Sessler, Andrew M; Staples, John W; Tabak, Max; Thoma, Carsten H; Waldron, William; Welch, Dale; Wurtele, Jonathan; Yu, Simon

    2005-01-01

    The Heavy Ion Fusion Virtual National Laboratory (HIF-VNL) is developing the intense ion beams needed to drive matter to the High Energy Density (HED) regimes required for Inertial Fusion Energy (IFE) and other applications. An interim goal is a facility for Warm Dense Matter (WDM) studies, wherein a target is heated volumetrically without being shocked, so that well-defined states of matter at 1 to 10 eV are generated within a diagnosable region. In the approach we are pursuing, low to medium mass ions with energies just above the Bragg peak are directed onto thin target "foils," which may in fact be foams or "steel wool" with mean densities 1% to 100% of solid. This approach complements that being pursued at GSI, wherein high-energy ion beams deposit a small fraction of their energy in a cylindrical target. We present the requirements for warm dense matter experiments, and describe suitable accelerator concepts, including novel broadband traveling wave pulse-line, drift-tube linac, RF, and single-gap approa...

  2. Ion energy and angular distributions in inductively coupled Argon RF discharges

    International Nuclear Information System (INIS)

    Woodworth, J.R.; Riley, M.E.; Meister, D.C.

    1996-03-01

    We report measurements of the energies and angular distributions of positive ions in an inductively coupled argon plasma in a GEC reference cell. Use of two separate ion detectors allowed measurement of ion energies and fluxes as a function of position as well as ion angular distributions on the discharge centerline. The inductive drive on our system produced high plasma densities (up to 10 12 /cm 3 electron densities) and relatively stable plasma potentials. As a result, ion energy distributions typically consisted of a single feature well separated from zero energy. Mean ion energy was independent of rf power and varied inversely with pressure, decreasing from 29 eV to 12 eV as pressure increased form 2.4 m Torr to 50 mTorr. Half-widths of the ion angular distributions in these experiments varied from 5 degrees to 12.5 degrees, or equivalently, transverse temperatures varied form 0.2 to 0.5 eV with the distributions broadening as either pressure or RF power were increased

  3. Energy and Pitch Distribution of Spontaneously-generated High-energy Bulk Ions in the RFP

    Science.gov (United States)

    Kim, Jungha; Anderson, Jay; Reusch, Joshua; Eilerman, Scott; Capecchi, William

    2014-10-01

    Magnetic reconnection events in the reversed field pinch (RFP) are known to heat bulk and impurity ions. Runaway due to a parallel electric field has recently been confirmed as an important acceleration mechanism for high energy test ions supplied by a neutral beam. This effect does not, however, explain the change in distribution of nearly Maxwellian bulk ions at a reconnection event. By operating MST near maximum current and low electron density, significant fusion neutron flux can be generated without neutral beam injection. The bulk ion distribution created in these plasmas is well-confined, non-Maxwellian, and can be measured by the Advanced Neutral Particle Analyzer (ANPA) placed at a radial or tangential porthole. Data show a high energy tail up to 25 keV with a relatively higher signal in the low energy channels (8-15 keV) at the radial port following a reconnection event. Analysis of the energy dependence of trapped orbits sampled by the ANPA at the radial view implies an abundance of lower energy particles in regions of higher neutral density. This mandates a careful deconvolution of the measured ANPA signal to compute the fast ion distribution. This work is supported by the US DOE and NSF.

  4. Deactivation kinetics of acid-sensing ion channel 1a are strongly pH-sensitive.

    Science.gov (United States)

    MacLean, David M; Jayaraman, Vasanthi

    2017-03-21

    Acid-sensing ion channels (ASICs) are trimeric cation-selective ion channels activated by protons in the physiological range. Recent reports have revealed that postsynaptically localized ASICs contribute to the excitatory postsynaptic current by responding to the transient acidification of the synaptic cleft that accompanies neurotransmission. In response to such brief acidic transients, both recombinant and native ASICs show extremely rapid deactivation in outside-out patches when jumping from a pH 5 stimulus to a single resting pH of 8. Given that the resting pH of the synaptic cleft is highly dynamic and depends on recent synaptic activity, we explored the kinetics of ASIC1a and 1a/2a heteromers to such brief pH transients over a wider [H + ] range to approximate neuronal conditions better. Surprisingly, the deactivation of ASICs was steeply dependent on the pH, spanning nearly three orders of magnitude from extremely fast (pH 8 to very slow (>300 ms) at pH 7. This study provides an example of a ligand-gated ion channel whose deactivation is sensitive to agonist concentrations that do not directly activate the receptor. Kinetic simulations and further mutagenesis provide evidence that ASICs show such steeply agonist-dependent deactivation because of strong cooperativity in proton binding. This capacity to signal across such a large synaptically relevant bandwidth enhances the response to small-amplitude acidifications likely to occur at the cleft and may provide ASICs with the ability to shape activity in response to the recent history of the synapse.

  5. Heavy Ion Fusion Accelerator Research (HIFAR) year-end report, April 1, 1985-September 30, 1985

    International Nuclear Information System (INIS)

    1985-10-01

    The heavy ion accelerator is profiled. Energy losses, currents, kinetic energy, beam optics, pulse models and mechanical tolerances are included in the discussion. In addition, computational efforts and an energy analyzer are described. 37 refs., 27 figs

  6. Modification of high density polyethylene by gold implantation using different ion energies

    Energy Technology Data Exchange (ETDEWEB)

    Nenadović, M.; Potočnik, J. [INS Vinca, Laboratory of Atomic Physics, University of Belgrade, Mike Alasa 12–14, 11001 Belgrade (Serbia); Mitrić, M. [INS Vinca, Condensed Matter Physics Laboratory, University of Belgrade, Mike Alasa 12–14, 11001 Belgrade (Serbia); Štrbac, S. [ICTM Institute of Electrochemistry, University of Belgrade, Njegoseva 12, 11001 Belgrade (Serbia); Rakočević, Z., E-mail: zlatkora@vinca.rs [INS Vinca, Laboratory of Atomic Physics, University of Belgrade, Mike Alasa 12–14, 11001 Belgrade (Serbia)

    2013-11-01

    High density polyethylene (HDPE) samples were modified by Au{sup +} ion implantation at a dose of 5 × 10{sup 15} ions cm{sup −2}, using energies of 50, 100, 150 and 200 keV. The existence of implanted gold in the near-surface region of HDPE samples was confirmed by X-ray diffraction analysis. Surface roughness and Power Spectral Density analyses based on Atomic Force Microscopy (AFM) images of the surface topography revealed that the mechanism of HDPE modification during gold ion implantation depended on the energy of gold ions. Histograms obtained from phase AFM images indicated a qualitative change in the chemical composition of the surface during implantation with gold ions with different energies. Depth profiles obtained experimentally from cross-sectional Force Modulation Microscopy images and ones obtained from a theoretical simulation are in agreement for gold ions energies lower than 100 keV. The deviation that was observed for higher energies of the gold ions is explained by carbon precipitation in the near surface region of the HDPE, which prevented the penetration of gold ions further into the depth of the sample. - Highlights: • HDPE was implanted by Au{sup +} ions using energies of 50, 100, 150 and 200 keV. • Surface composition was analyzed from phase AFM images. • FMM depth profiles are in agreement with theoretical ones for energies up to 100 keV. • A deviation is observed for higher gold ion energies.

  7. Modification of high density polyethylene by gold implantation using different ion energies

    International Nuclear Information System (INIS)

    Nenadović, M.; Potočnik, J.; Mitrić, M.; Štrbac, S.; Rakočević, Z.

    2013-01-01

    High density polyethylene (HDPE) samples were modified by Au + ion implantation at a dose of 5 × 10 15 ions cm −2 , using energies of 50, 100, 150 and 200 keV. The existence of implanted gold in the near-surface region of HDPE samples was confirmed by X-ray diffraction analysis. Surface roughness and Power Spectral Density analyses based on Atomic Force Microscopy (AFM) images of the surface topography revealed that the mechanism of HDPE modification during gold ion implantation depended on the energy of gold ions. Histograms obtained from phase AFM images indicated a qualitative change in the chemical composition of the surface during implantation with gold ions with different energies. Depth profiles obtained experimentally from cross-sectional Force Modulation Microscopy images and ones obtained from a theoretical simulation are in agreement for gold ions energies lower than 100 keV. The deviation that was observed for higher energies of the gold ions is explained by carbon precipitation in the near surface region of the HDPE, which prevented the penetration of gold ions further into the depth of the sample. - Highlights: • HDPE was implanted by Au + ions using energies of 50, 100, 150 and 200 keV. • Surface composition was analyzed from phase AFM images. • FMM depth profiles are in agreement with theoretical ones for energies up to 100 keV. • A deviation is observed for higher gold ion energies

  8. Yields of clustered DNA damage induced by charged-particle radiations of similar kinetic energy per nucleon: LET dependence in different DNA microenvironments

    International Nuclear Information System (INIS)

    Keszenman, D.J.; Sutherland, B.M.

    2010-01-01

    To determine the linear energy transfer (LET) dependence of the biological effects of densely ionizing radiation in relation to changes in the ionization density along the track, we measured the yields and spectrum of clustered DNA damages induced by charged particles of different atomic number but similar kinetic energy per nucleon in different DNA microenvironments. Yeast DNA embedded in agarose in solutions of different free radical scavenging capacity was irradiated with 1 GeV protons, 1 GeV/nucleon oxygen ions, 980 MeV/nucleon titanium ions or 968 MeV/nucleon iron ions. The frequencies of double-strand breaks (DSBs), abasic sites and oxypurine clusters were quantified. The total DNA damage yields per absorbed dose induced in non-radioquenching solution decreased with LET, with minor variations in radioquenching conditions being detected. However, the total damage yields per particle fluence increased with LET in both conditions, indicating a higher efficiency per particle to induce clustered DNA damages. The yields of DSBs and non-DSB clusters as well as the damage spectra varied with LET and DNA milieu, suggesting the involvement of more than one mechanism in the formation of the different types of clustered damages.

  9. Evaluation of Zirconium Silico phosphate Material for the Removal of Copper Ions from Waste Water

    International Nuclear Information System (INIS)

    Abd El-Mohsen, E.S.; El-Naggar, M.R.; EI-Naggar, I.M.; El-Shahhat, M.F.

    2014-01-01

    Zirconium silico phosphate/polyacrylamide (ZrSP/PAA) nano composite was synthesized. Synthesis process was based on the intercalation polymerization technique. The obtained nano product was characterized using XRF, XRD, FTIR, TG-DTA, SEM and TEM techniques. The physicochemical properties indicated that the synthesized material was semicrystalline in nature with a particle size in the nan orange (45 nm). FTIR analysis suggested that the intercalation polymerization was achieved via hydrogen bonding. The kinetics of copper retention at different temperatures were analyzed using pseudo first-order, pseudo second-order and Helfferich kinetic models. Kinetic modeling of the experimentally obtained data indicated that the intra-particle diffusion was the controlled mechanism of the sorption process. Various parameters such as effective diffusion coefficient and activation energy were evaluated. The mean free energy was in the range corresponding to the ion exchange type of sorption. Results indicated that synthetic ZrSP/PAA nano composite can be used as an efficient ion exchange material for the removal of cupper ions from waste water

  10. Low energy helium ion irradiation induced nanostructure formation on tungsten surface

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ajlony, A., E-mail: montaserajlony@yahoo.com; Tripathi, J.K.; Hassanein, A.

    2017-05-15

    We report on the low energy helium ion irradiation induced surface morphology changes on tungsten (W) surfaces under extreme conditions. Surface morphology changes on W surfaces were monitored as a function of helium ion energy (140–300 eV), fluence (2.3 × 10{sup 24}–1.6 × 10{sup 25} ions m{sup −2}), and flux (2.0 × 10{sup 20}–5.5 × 10{sup 20} ion m{sup −2} s{sup −1}). All the experiments were performed at 900° C. Our study shows significant effect of all the three ion irradiation parameters (ion flux, fluence, and energy) on the surface morphology. However, the effect of ion flux is more pronounced. Variation of helium ion fluence allows to capture the very early stages of fuzz growth. The observed fuzz growth and morphology changes were understood in the realm of various possible phenomena. The study has relevance and important impact in the current and future nuclear fusion applications. - Highlights: •Reporting formation of W nanostructure (fuzz) due to low energy He ion beam irradiation. •Observing the very early stages for the W-Fuzz formation. •Tracking the surface morphological evolution during the He irradiation. •Discussing in depth our observation and drawing a possible scenario that explain this phenomenon. •Studying various ions irradiation parameters such as flux, fluence, and ions energy.

  11. Nonlinear energy loss of highly charged heavy ions

    International Nuclear Information System (INIS)

    Zwicknagel, G.Guenter.

    2000-01-01

    For slow, highly charged heavy ions strong coupling effects in the energy transfer from the projectile-ion to an electron target plasma become important. A theoretical description of this nonlinear ion stopping has to go beyond the standard approaches like the dielectric linear response or the binary collision model which are strictly valid only at weak ion-target coupling. Here we outline an improved treatment which is based on a suitable combination of binary collision and linear response contributions. As has been verified for isotropic, nonmagnetized electron plasmas by comparison with simulations, this approach well reproduces the essential features of nonlinear stopping up to moderate coupling strength. Its extension to anisotropic, magnetized electron plasmas basically involves the fully numerical determination of the momentum and energy transfer in binary ion-electron collisions in the presence of a magnetic field. First results of such calculations are presented and discussed

  12. Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions

    Directory of Open Access Journals (Sweden)

    Raghunath Sahoo

    2015-01-01

    Full Text Available We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement.

  13. Characteristics of transitory multi-charged molecular ions produced by an intense femtosecond laser impulse; Etats electroniques des ions moleculaires multicharges transitoires produits par une impulsion laser femtoseconde intense

    Energy Technology Data Exchange (ETDEWEB)

    Quaglia, L

    2001-12-01

    The study of the molecular multi-ionization is narrowly linked to the dynamics of excitation and fragmentation for which the experimental observables rest on the characteristics of the fragmentation products, these characteristics are: intern energy, kinetic energy and charge states. The first chapter sets the problem. The second chapter presents the experimental tools used and developed in this work, the technologies of the detection of ions or of fluorescence are also described. The chapter 3 gathers the theoretical aspects: quantum chemistry and CASSCF (complete active space self consistent field) methods have been used to compute the potential energy curves of multi-charged ions, the two-dimensional hydrodynamic model derived from the Thomas-Fermi model is introduced to tackle the molecular re-orientation. The chapter 4 presents the experimental study of highly excited states by using fluorescence detection methods. The chapter 5 is dedicated to the study of low excited states by measuring kinetic energy spectra and by comparison with potential energy curves of molecular multi-charged ions. The chapter 6 presents experiments with 2 impulses and the results given by the Thomas-Fermi model applied to the re-orientation of the N{sub 2}O molecule. (A.C.)

  14. Ion-molecule reactions: their role in radiation chemistry

    International Nuclear Information System (INIS)

    Lias, S.G.; Ausloos, P.

    1975-01-01

    A comprehensive review of ion--molecule reactions is presented, including information from mass spectrometric, organic chemistry, and NMR studies, from theoretical calculations, and from gas and liquid phase radiation chemistry. Special emphasis is placed on interpreting the role of ion--molecule reactions in systems under high energy irradiation. The discussion is presented under the following chapter headings: ion--molecule reactions and their role in radiation chemistry; unimolecular processes: the nature and structure of ionic intermediates in radiolysis; ion lifetimes and the fate of unreactive ions; kinetics and mechanisms of ion--molecule reactions; proton transfer reactions; negative atom and two-atom transfer reactions; condensation reactions; and, association or clustering reactions

  15. Global fully kinetic models of planetary magnetospheres with iPic3D

    Science.gov (United States)

    Gonzalez, D.; Sanna, L.; Amaya, J.; Zitz, A.; Lembege, B.; Markidis, S.; Schriver, D.; Walker, R. J.; Berchem, J.; Peng, I. B.; Travnicek, P. M.; Lapenta, G.

    2016-12-01

    We report on the latest developments of our approach to model planetary magnetospheres, mini magnetospheres and the Earth's magnetosphere with the fully kinetic, electromagnetic particle in cell code iPic3D. The code treats electrons and multiple species of ions as full kinetic particles. We review: 1) Why a fully kinetic model and in particular why kinetic electrons are needed for capturing some of the most important aspects of the physics processes of planetary magnetospheres. 2) Why the energy conserving implicit method (ECIM) in its newest implementation [1] is the right approach to reach this goal. We consider the different electron scales and study how the new IECIM can be tuned to resolve only the electron scales of interest while averaging over the unresolved scales preserving their contribution to the evolution. 3) How with modern computing planetary magnetospheres, mini magnetosphere and eventually Earth's magnetosphere can be modeled with fully kinetic electrons. The path from petascale to exascale for iPiC3D is outlined based on the DEEP-ER project [2], using dynamic allocation of different processor architectures (Xeon and Xeon Phi) and innovative I/O technologies.Specifically results from models of Mercury are presented and compared with MESSENGER observations and with previous hybrid (fluid electrons and kinetic ions) simulations. The plasma convection around the planets includes the development of hydrodynamic instabilities at the flanks, the presence of the collisionless shocks, the magnetosheath, the magnetopause, reconnection zones, the formation of the plasma sheet and the magnetotail, and the variation of ion/electron plasma flows when crossing these frontiers. Given the full kinetic nature of our approach we focus on detailed particle dynamics and distribution at locations that can be used for comparison with satellite data. [1] Lapenta, G. (2016). Exactly Energy Conserving Implicit Moment Particle in Cell Formulation. arXiv preprint ar

  16. Numerical analysis of energy density and particle density in high energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Fu Yuanyong; Lu Zhongdao

    2004-01-01

    Energy density and particle density in high energy heavy-ion collisions are calculated with infinite series expansion method and Gauss-Laguerre formulas in numerical integration separately, and the results of these two methods are compared, the higher terms and linear terms in series expansion are also compared. The results show that Gauss-Laguerre formulas is a good method in calculations of high energy heavy-ion collisions. (author)

  17. Independent control of ion current and ion impact energy onto electrodes in dual frequency plasma devices

    International Nuclear Information System (INIS)

    Boyle, P C; Ellingboe, A R; Turner, M M

    2004-01-01

    Dual frequency capacitive discharges are designed to offer independent control of the flux and energy of ions impacting on an object immersed in a plasma. This is desirable in applications such as the processing of silicon wafers for microelectronics manufacturing. In such discharges, a low frequency component couples predominantly to the ions, while a high frequency component couples predominantly to electrons. Thus, the low frequency component controls the ion energy, while the high frequency component controls the plasma density. Clearly, this desired behaviour is not achieved for arbitrary configurations of the discharge, and in general one expects some unwanted coupling of ion flux and energy. In this paper we use computer simulations with the particle-in-cell method to show that the most important governing parameter is the ratio of the driving frequencies. If the ratio of the high and low frequencies is great enough, essentially independent control of the ion energy and flux is possible by manipulation of the high and low frequency power sources. Other operating parameters, such as pressure, discharge geometry, and absolute power, are of much less significance

  18. Redistribution of Kinetic Energy in Turbulent Flows

    Directory of Open Access Journals (Sweden)

    Alain Pumir

    2014-10-01

    Full Text Available In statistically homogeneous turbulent flows, pressure forces provide the main mechanism to redistribute kinetic energy among fluid elements, without net contribution to the overall energy budget. This holds true in both two-dimensional (2D and three-dimensional (3D flows, which show fundamentally different physics. As we demonstrate here, pressure forces act on fluid elements very differently in these two cases. We find in numerical simulations that in 3D pressure forces strongly accelerate the fastest fluid elements, and that in 2D this effect is absent. In 3D turbulence, our findings put forward a mechanism for a possibly singular buildup of energy, and thus may shed new light on the smoothness problem of the solution of the Navier-Stokes equation in 3D.

  19. ION KINETIC ENERGY CONSERVATION AND MAGNETIC FIELD STRENGTH CONSTANCY IN MULTI-FLUID SOLAR WIND ALFVÉNIC TURBULENCE

    Energy Technology Data Exchange (ETDEWEB)

    Matteini, L.; Horbury, T. S.; Schwartz, S. J. [The Blackett Laboratory, Imperial College London, SW7 2AZ (United Kingdom); Pantellini, F. [LESIA, Observatoire de Paris, CNRS, UPMC, Universit Paris-Diderot, 5 Place Jules Janssen, F-92195 Meudon (France); Velli, M. [Department of Earth, Planetary, and Space Sciences, UCLA, California (United States)

    2015-03-20

    We investigate the properties of plasma fluid motion in the large-amplitude, low-frequency fluctuations of highly Alfvénic fast solar wind. We show that protons locally conserve total kinetic energy when observed from an effective frame of reference comoving with the fluctuations. For typical properties of the fast wind, this frame can be reasonably identified by alpha particles which, due to their drift with respect to protons at about the Alfvén speed along the magnetic field, do not partake in the fluid low-frequency fluctuations. Using their velocity to transform the proton velocity into the frame of Alfvénic turbulence, we demonstrate that the resulting plasma motion is characterized by a constant absolute value of the velocity, zero electric fields, and aligned velocity and magnetic field vectors as expected for unidirectional Alfvénic fluctuations in equilibrium. We propose that this constraint, via the correlation between velocity and magnetic field in Alfvénic turbulence, is the origin of the observed constancy of the magnetic field; while the constant velocity corresponding to constant energy can only be observed in the frame of the fluctuations, the corresponding constant total magnetic field, invariant for Galilean transformations, remains the observational signature in the spacecraft frame of the constant total energy in the Alfvén turbulence frame.

  20. Trajectory bending and energy spreading of charged ions in time-of-flight telescopes used for ion beam analysis

    International Nuclear Information System (INIS)

    Laitinen, Mikko; Sajavaara, Timo

    2014-01-01

    Carbon foil time pick-up detectors are widely used in pairs in ion beam applications as time-of-flight detectors. These detectors are suitable for a wide energy range and for all ions but at the lowest energies the tandem effect limits the achievable time of flight and therefore the energy resolution. Tandem effect occurs when an ion passes the first carbon foil of the timing detector and its charge state is changed. As the carbon foil of the first timing detector has often a non-zero voltage the ion can accelerate or decelerate before and after the timing detector. The combination of different charge state properties before and after the carbon foil now induces spread to the measured times of flight. We have simulated different time pick-up detector orientations, voltages, ions and ion energies to examine the tandem effect in detail and found out that the individual timing detector orientation and the average ion charge state have a very small influence to the magnitude of the tandem effect. On the other hand, the width of the charge state distribution for particular ion and energy in the first carbon foil, and the carbon foil voltage contributes linearly to the magnitude of the tandem effect. In the simulations low energy light ion trajectories were observed to bend in the electric fields of the first timing gate, and the magnitude of this bending was studied. It was found out that 50–150 keV proton trajectories can even bend outside the second timing gate

  1. Universal trend for heavy-ion total reaction cross sections at energies above the Coulomb barrier

    International Nuclear Information System (INIS)

    Tavares, O.A.P.; Medeiros, E.L.; Morcelle, V.

    2010-06-01

    Heavy-ion total reaction cross section measurements for more than one thousand one hundred reaction cases covering 61 target nuclei in the range 6 Li- 238 U, and 158 projectile nuclei from 2 H up to 84 Kr (mostly exotic ones) have been analysed in a systematic way by using an empirical, three-parameter formula which is applicable to cases for projectile kinetic energies above the Coulomb barrier. The analysis has shown that the average total nuclear binding energy per nucleon of the interacting nuclei and their radii are the chief quantities which describe the cross section patterns. A great number of cross section data (87%) has been quite satisfactorily reproduced by the proposed formula, therefore total reaction cross section predictions for new, not yet experimentally investigated reaction cases can be obtained within 25 percent (or much less) of uncertainty (author)

  2. Computer-controlled system for plasma ion energy auto-analyzer

    International Nuclear Information System (INIS)

    Wu Xianqiu; Chen Junfang; Jiang Zhenmei; Zhong Qinghua; Xiong Yuying; Wu Kaihua

    2003-01-01

    A computer-controlled system for plasma ion energy auto-analyzer was technically studied for rapid and online measurement of plasma ion energy distribution. The system intelligently controls all the equipments via a RS-232 port, a printer port and a home-built circuit. The software designed by LabVIEW G language automatically fulfils all of the tasks such as system initializing, adjustment of scanning-voltage, measurement of weak-current, data processing, graphic export, etc. By using the system, a few minutes are taken to acquire the whole ion energy distribution, which rapidly provide important parameters of plasma process techniques based on semiconductor devices and microelectronics

  3. Effects of energy variations of ions influencing a target on implantation

    International Nuclear Information System (INIS)

    Astakhov, V.P.; Rubtsov, V.A.; Aranovich, R.M.; Pavlov, P.V.

    1981-01-01

    In cases of phosphorus and boron ion implantation into silicon the dependence of electrophysical properties of ion-doped layers and target material near the layer boundaries on energy variation conditions of influencing ions is observed. A physical model explaining the dependence is proposed. It is found that for the target, being at room temperature, after successive annealing the qualitative characteristics of conditions (i.e. energy increase and decrease) on implantation of phosphorus ions into p-silicon and boron ions into n-silicon, as well as the value of energy stages, define rhosub(l) ion-doped layer resistivity and tausub(mc) nonequilibrium minority carrier lifetime in the base of p-n transitions. The essence of the effects observed is that for equal sets of Esub(i) ion energy values and PHIsub(i) corresponding phases at maximum energy used exceeding 30 keV, successive energy increase during implantation, when E 1 2 1 mode), leads to smaller rhosub(e) values and greater tausub(mc) than in case of successive energy decrease, when E 1 >E 2 >...E(E 2 mode) for any fixed annealing temperature. In cases when the maximum energy does not exceed 30 KeV, the E 1 and E 2 modes lead to analogous rhosub(e) and tausub(mc) values. The E 2 mode leads to enrichment of the ion-implanted layer with associations and complexes on the basis of interstitial atoms in comparison with the E 1 mode. The associations and complexes on thermal treatment are reformed into the higher-temperature interstitial complexes increasing rhosub(e) and decreasing tausub(mc). Supposition about the effect of these complexes and processes of structural transformations on annealing, hampering-improvement of structural properties of the ion-implanted layer and a crystal region bordered on it [ru

  4. A high-energy electron beam ion trap for production of high-charge high-Z ions

    International Nuclear Information System (INIS)

    Knapp, D.A.; Marrs, R.E.; Elliott, S.R.; Magee, E.W.; Zasadzinski, R.

    1993-01-01

    We have developed a new high-energy electron beam ion trap, the first laboratory source of low-energy, few-electron, high-Z ions. We describe the device and report measurements of its performance, including the electron beam diameter, current density and energy, and measurements of the ionization balance for several high-Z elements in the trap. This device opens up a wide range of possible experiments in atomic physics, plasma physics, and nuclear physics. (orig.)

  5. Electron-ion recombination at low energy

    International Nuclear Information System (INIS)

    Andersen, L.H.

    1993-01-01

    The work is based on results obtained with a merged-beams experiment. A beam of electronics with a well characterized density and energy distribution was merged with a fast, monoenergetic ion beam. Results have been obtained for radiative recombination and dielectronic recombination at low relative energies (0 to ∼70eV). The obtained energy resolution was improved by about a factor of 30. High vacuum technology was used to suppress interactions with electrons from the environments. The velocity distribution of the electron beam was determined. State-selective dielectronic-recombination measurements were performable. Recombination processes were studied. The theoretical background for radiative recombination and Kramers' theory are reviewed. The quantum mechanical result and its relation to the semiclassical theory is discussed. Radiative recombination was also measured with several different non-bare ions, and the applicability of the semiclassical theory to non-bare ions was investigated. The use of an effective charge is discussed. For dielectronic recombination, the standard theoretical approach in the isolated resonance and independent-processes approximation is debated. The applicability of this method was tested. The theory was able to reproduce most of the experimental data except when the recombination process was sensitive to couplings between different electronic configurations. The influence of external perturbing electrostatic fields is discussed. (AB) (31 refs.)

  6. Amorphous Ge quantum dots embedded in SiO2 formed by low energy ion implantation

    International Nuclear Information System (INIS)

    Zhao, J. P.; Huang, D. X.; Jacobson, A. J.; Chen, Z. Y.; Makarenkov, B.; Chu, W. K.; Bahrim, B.; Rabalais, J. W.

    2008-01-01

    Under ultrahigh vacuum conditions, extremely small Ge nanodots embedded in SiO 2 , i.e., Ge-SiO 2 quantum dot composites, have been formed by ion implantation of 74 Ge + isotope into (0001) Z-cut quartz at a low kinetic energy of 9 keV using varying implantation temperatures. Transmission electron microscopy (TEM) images and micro-Raman scattering show that amorphous Ge nanodots are formed at all temperatures. The formation of amorphous Ge nanodots is different from reported crystalline Ge nanodot formation by high energy ion implantation followed by a necessary high temperature annealing process. At room temperature, a confined spatial distribution of the amorphous Ge nanodots can be obtained. Ge inward diffusion was found to be significantly enhanced by a synergetic effect of high implantation temperature and preferential sputtering of surface oxygen, which induced a much wider and deeper Ge nanodot distribution at elevated implantation temperature. The bimodal size distribution that is often observed in high energy implantation was not observed in the present study. Cross-sectional TEM observation and the depth profile of Ge atoms in SiO 2 obtained from x-ray photoelectron spectra revealed a critical Ge concentration for observable amorphous nanodot formation. The mechanism of formation of amorphous Ge nanodots and the change in spatial distribution with implantation temperature are discussed

  7. Probing thin over layers with variable energy/cluster ion beams

    International Nuclear Information System (INIS)

    Spool, A.; White, R.

    2006-01-01

    A series of carbon-coated magnetic recording disks proved ideal for exploring sampling depth and ion formation trends as a function of variations in energy and cluster size (Au x ) of the primary ion beam, and variations in over coat thickness and type. Ion yield from the underlying metal layer increased with increasing energy and decreasing cluster size of the primary ions. The yields varied nearly linearly with over layer thickness. In contrast, M x Cs y depth profiles were unaffected by changes in the primary ion. The samples were fortuitously dosed with dinonyl phthalate, allowing a study similar to prior GSIMS work [I.S. Gilmore, M.P. Seah, J.E. Johnstone, in: A. Benninghoven, P. Bertrand, H.-N. Migeon, H.W. Werner (Eds.), Proceedings of the 12th International Conference on SIMS, Elsevier, Brussels, 2000, p. 801]. Ions prominent in the EI mass spectrum, including even electron ions, were more consistently enhanced at lower energies and higher cluster sizes than the primary (M + H) + ion. The total secondary ion count was inversely proportional to the film thickness. Secondary electrons, largely originating in the buried metal layer, may be inducing organic ion formation [A.M. Spool, Surf. Interface Anal. 36 (2004) 264

  8. Production of low axial energy spread ion beams with multicusp sources

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yung -Hee Y. [Univ. of California, Berkeley, CA (United States)

    1998-05-01

    Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution.

  9. Production of low axial energy spread ion beams with multicusp sources

    International Nuclear Information System (INIS)

    Lee, Y.H.Y.

    1998-05-01

    Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution

  10. Kinetic energy of throughfall in a highly diverse forest ecosystem in the humid subtropics

    Science.gov (United States)

    Geißler, Christian; Kühn, Peter; Scholten, Thomas

    2010-05-01

    After decades of research it is generally accepted that vegetation is a key factor in controlling soil erosion. Therefore, in ecosystems where erosion is a serious problem, afforestation is a common measure against erosion. Most of the studies in the last decades focused on agricultural systems and less attention was paid to natural systems. To understand the mechanisms preventing soil erosion in natural systems the processes have to be studied in detail and gradually. The first step and central research question is on how the canopies of the tree layer alter the properties of rainfall and generate throughfall. Kinetic energy is a widely used parameter to estimate the erosion potential of open field rainfall and throughfall. In the past, numerous studies have shown that vegetation of a certain height enhances the kinetic energy under the canopy (Chapman 1948, Mosley 1982, Vis 1986, Hall & Calder 1993, Nanko et al. 2006, Nanko et al. 2008) in relation to open field rainfall. This is mainly due to a shift in the drop size distribution to less but larger drops possessing a higher amount of kinetic energy. In vital forest ecosystems lower vegetation (shrubs, herbs) as well as a continuous litter layer protects the forest soil from the impact of large drops. The influence of biodiversity, specific forest stands or single species in this process system is still in discussion. In the present study calibrated splash cups (after Ellison 1947, Geißler et al. under review) have been used to detect differences in kinetic energy on the scale of specific species and on the scale of forest stands of contrasting age and biodiversity in a natural forest ecosystem. The splash cups have been calibrated experimentally using a laser disdrometer. The results show that the kinetic energy of throughfall produced by the tree layer increases with the age of the specific forest stand. The average throughfall kinetic energy (J m-2) is about 2.6 times higher in forests than under open field

  11. Ion heating, burnout of the high-frequency field, and ion sound generation under the development of a modulation instability of an intense Langmuir wave in a plasma

    Science.gov (United States)

    Kirichok, A. V.; Kuklin, V. M.; Pryimak, A. V.; Zagorodny, A. G.

    2015-09-01

    The development of one-dimensional parametric instabilities of intense long plasma waves is considered in terms of the so-called hybrid models, with electrons being treated as a fluid and ions being regarded as particles. The analysis is performed for both cases when the average plasma field energy is lower (Zakharov's hybrid model—ZHM) or greater (Silin's hybrid model—SHM) than the plasma thermal energy. The efficiency of energy transfer to ions and to ion perturbations under the development of the instability is considered for various values of electron-to-ion mass ratios. The energy of low-frequency oscillations (ion-sound waves) is found to be much lower than the final ion kinetic energy. We also discuss the influence of the changes in the damping rate of the high-frequency (HF) field on the instability development. The decrease of the absorption of the HF field inhibits the HF field burnout within plasma density cavities and gives rise to the broadening of the HF spectrum. At the same time, the ion velocity distribution tends to the normal distribution in both ZHM and SHM.

  12. Quasilinear ion distribution function during first harmonic ion cyclotron heating

    International Nuclear Information System (INIS)

    Brambilla, M.

    1993-12-01

    The quasilinear modification of the ion distribution function during first harmonic ion cyclotron (FHIC) heating is investigated both with a simple already well established analytic one-dimensional approach, and with a new two dimensional steady state solver of the quasilinear kinetic equation, SSFPQL. By accepting to disregard the effects of ion trapping in banana orbits, but including finite Larmor radius effects, the latter code has been made much faster than full surface-averaged codes; yet it can provide most of the relevant information on the suprathermal ion tail produced by this heating method. With SSFPQL we confirm that the one-dimensional model gives fair approximations for global properties of the distribution function, such as the average energy content of the tail and the fusion reactivity. On the other hand the tail is found to be very anisotropic, the increase of the parallel effective temperature being a small fraction of the total energy increase. Information on the anisotropy is essential to study the feedback of the fast ion tail on wave propagation and absorption, which is quite sensitive to the distribution of parallel velocities. The insight gained in the derivation and discussion of this model can be used to build a selfconsistent description of this heating scenario, whose implementation requires only a reasonable numerical effort. (orig.)

  13. Astrophysical gyrokinetics: turbulence in pressure-anisotropic plasmas at ion scales and beyond

    Science.gov (United States)

    Kunz, M. W.; Abel, I. G.; Klein, K. G.

    2018-04-01

    We present a theoretical framework for describing electromagnetic kinetic turbulence in a multi-species, magnetized, pressure-anisotropic plasma. The turbulent fluctuations are assumed to be small compared to the mean field, to be spatially anisotropic with respect to it and to have frequencies small compared to the ion cyclotron frequency. At scales above the ion-Larmor radius, the theory reduces to the pressure-anisotropic generalization of kinetic reduced magnetohydrodynamics (KRMHD) formulated by Kunz et al. (J. Plasma Phys., vol. 81, 2015, 325810501). At scales at and below the ion-Larmor radius, three main objectives are achieved. First, we analyse the linear response of the pressure-anisotropic gyrokinetic system, and show it to be a generalization of previously explored limits. The effects of pressure anisotropy on the stability and collisionless damping of Alfvénic and compressive fluctuations are highlighted, with attention paid to the spectral location and width of the frequency jump that occurs as Alfvén waves transition into kinetic Alfvén waves. Secondly, we derive and discuss a very general gyrokinetic free-energy conservation law, which captures both the KRMHD free-energy conservation at long wavelengths and dual cascades of kinetic Alfvén waves and ion entropy at sub-ion-Larmor scales. We show that non-Maxwellian features in the distribution function change the amount of phase mixing and the efficiency of magnetic stresses, and thus influence the partitioning of free energy amongst the cascade channels. Thirdly, a simple model is used to show that pressure anisotropy, even within the bounds imposed on it by firehose and mirror instabilities, can cause order-of-magnitude variations in the ion-to-electron heating ratio due to the dissipation of Alfvénic turbulence. Our theory provides a foundation for determining how pressure anisotropy affects turbulent fluctuation spectra, the differential heating of particle species and the ratio of parallel

  14. Kinetic energy recovery and power management for hybrid electric vehicles

    OpenAIRE

    Suntharalingam, P

    2011-01-01

    The major contribution of the work presented in this thesis is a thorough investigation of the constraints on regenerative braking and kinetic energy recovery enhancement for electric/hybrid electric vehicles during braking. Regenerative braking systems provide an opportunity to recycle the braking energy, which is otherwise dissipated as heat in the brake pads. However, braking energy harnessing is a relatively new concept in the automotive sector which still requires further research and de...

  15. Collisional Activation of Peptide Ions in FT-ICR Mass Spectrometry

    International Nuclear Information System (INIS)

    Laskin, Julia; Futrell, Jean H.

    2003-01-01

    In the last decade characterization of complex molecules, particularly biomolecules became a focus of both fundamental and applied research in mass spectrometry. Most of these studies utilize tandem mass spectrometry (MS/MS) for obtaining structural information for complex molecules. . Tandem mass spectrometry (MS/MS) typically involves the mass selection of a primary ion, its activation by collision or photon excitation, unimolecular decay into fragment ions characteristic of the ion structure and its internal excitation, and mass analysis of the fragment ions. Although the fundamental principles of tandem mass spectrometry of relatively small molecules are fairly well understood, our understanding of the activation and fragmentation of large molecules is much more primitive. For small ions a single energetic collision is sufficient to dissociate the ion but this is not the case for complex molecules. For large ions two fundamental limits severely constrain fragmentation in tandem mass spectrometry. First the center-of-mass collision energy?the absolute upper limit of energy transfer in a collision process?decreases with increasing mass of the projectile ion for fixed ion kinetic energy and neutral mass. Secondly, the dramatic increase in density of states with increasing internal degrees of freedom of the ion decreases the rate of dissociation by many orders of magnitude at a given internal energy. Consequently most practical MS/MS experiments with complex ions involve multiple collision activation (MCA-CID), multi-photon activation or surface-induced dissociation (SID). This review is focused on what has been learned in recent research studies concerned with fundamental aspects of MCA-CID and SID of model peptides with emphasis on experiments carried out using Fourier transform ion cyclotron resonance mass spectrometers (FT-ICR MS). These studies provide the first quantitative comparison of gas-phase multiple-collision activation and SID of peptide ions

  16. 'Collisional Activation of Peptide Ions in FT-ICR Mass Spectrometry'

    International Nuclear Information System (INIS)

    Laskin, Julia; Futrell, Jean H.

    2003-01-01

    In the last decade characterization of complex molecules, particularly biomolecules became a focus of both fundamental and applied research in mass spectrometry. Most of these studies utilize tandem mass spectrometry (MS/MS) for obtaining structural information for complex molecules. . Tandem mass spectrometry (MS/MS) typically involves the mass selection of a primary ion, its activation by collision or photon excitation, unimolecular decay into fragment ions characteristic of the ion structure and its internal excitation, and mass analysis of the fragment ions. Although the fundamental principles of tandem mass spectrometry of relatively small molecules are fairly well understood, our understanding of the activation and fragmentation of large molecules is much more primitive. For small ions a single energetic collision is sufficient to dissociate the ion but this is not the case for complex molecules. For large ions two fundamental limits severely constrain fragmentation in tandem mass spectrometry. First the center-of-mass collision energy?the absolute upper limit of energy transfer in a collision process?decreases with increasing mass of the projectile ion for fixed ion kinetic energy and neutral mass. Secondly, the dramatic increase in density of states with increasing internal degrees of freedom of the ion decreases the rate of dissociation by many orders of magnitude at a given internal energy. Consequently most practical MS/MS experiments with complex ions involve multiple collision activation (MCA-CID), multi-photon activation or surface-induced dissociation (SID). This review is focused on what has been learned in recent research studies concerned with fundamental aspects of MCA-CID and SID of model peptides with emphasis on experiments carried out using Fourier transform ion cyclotron resonance mass spectrometers (FT-ICR MS). These studies provide the first quantitative comparison of gas-phase multiple-collision activation and SID of peptide ions

  17. Ultralow energy ion beam surface modification of low density polyethylene.

    Science.gov (United States)

    Shenton, Martyn J; Bradley, James W; van den Berg, Jaap A; Armour, David G; Stevens, Gary C

    2005-12-01

    Ultralow energy Ar+ and O+ ion beam irradiation of low density polyethylene has been carried out under controlled dose and monoenergetic conditions. XPS of Ar+-treated surfaces exposed to ambient atmosphere show that the bombardment of 50 eV Ar+ ions at a total dose of 10(16) cm(-2) gives rise to very reactive surfaces with oxygen incorporation at about 50% of the species present in the upper surface layer. Using pure O+ beam irradiation, comparatively low O incorporation is achieved without exposure to atmosphere (approximately 13% O in the upper surface). However, if the surface is activated by Ar+ pretreatment, then large oxygen contents can be achieved under subsequent O+ irradiation (up to 48% O). The results show that for very low energy (20 eV) oxygen ions there is a dose threshold of about 5 x 10(15) cm(-2) before surface oxygen incorporation is observed. It appears that, for both Ar+ and O+ ions in this regime, the degree of surface modification is only very weakly dependent on the ion energy. The results suggest that in the nonequilibrium plasma treatment of polymers, where the ion flux is typically 10(18) m(-2) s(-1), low energy ions (<50 eV) may be responsible for surface chemical modification.

  18. Kinetic Modifications to MHD Phenomena in Toroidal Plasmas

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Gorelenkov, N.N.; Kramer, G.J.; Fredrickson, E.

    2004-01-01

    Particle kinetic effects involving small spatial and fast temporal scales can strongly affect MHD phenomena and the long time behavior of plasmas. In particular, kinetic effects such as finite ion gyroradii, trapped particle dynamics, and wave-particle resonances have been shown to greatly modify the stability of MHD modes. Here, the kinetic effects of trapped electron dynamics and finite ion gyroradii are shown to have a large stabilizing effect on kinetic ballooning modes in low aspect ratio toroidal plasmas such as NSTX [National Spherical Torus Experiment]. We also present the analysis of Toroidicity-induced Alfven Eigenmodes (TAEs) destabilized by fast neutral-beam injected ions in NSTX experiments and TAE stability in ITER due to alpha-particles and MeV negatively charged neutral beam injected ions

  19. Energy loss and charge exchange processes of high energy heavy ions channeled in crystals

    International Nuclear Information System (INIS)

    Poizat, J.C.; Andriamonje, S.; Anne, R.; Faria, N.V.d.C.; Chevallier, M.; Cohen, C.; Dural, J.; Farizon-Mazuy, B.; Gaillard, M.J.; Genre, R.; Hage-Ali, M.; Kirsch, R.; L'hoir, A.; Mory, J.; Moulin, J.; Quere, Y.; Remillieux, J.; Schmaus, D.; Toulemonde, M.

    1990-01-01

    The interaction of moving ions with single crystals is very sensitive to the orientation of the incident beam with respect to the crystalline directions of the target. Our experiments show that high energy heavy ion channeling deeply modifies their slowing down and charge exchange processes. This is due to the fact that channeled ions interact only with outershell target electrons, which means that the electron density they experience is very low and that the binding energy, and then the momentum distribution of these electrons, are quite different from the corresponding average values associated to random incidence. The two experimental studies presented here show the reduction of the energy loss rate for fast channeled heavy ions and illustrate the two aspects of channeling effects on charge exchange, the reduction of electron loss on one hand, and of electron capture on the other hand

  20. Mechanisms and kinetics of electrodeposition of alkali metals on solid and liquid mercury electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wenzhe.

    1993-01-01

    Electroreduction of alkali metal ions at mercury is an important area in electrochemistry related to the battery industry. In this work, four major topics were considered: alkali metal/mercury interactions; electrosorption of alkali metal ions on solid mercury; electroreduction of alkali metal/crown ether complexes; and ammonium amalgam formation. The formation of alkali metal-mercury intermetallic compounds was studied on liquid and frozen thin layer mercury electrodes. The stoichiometry of the compounds produced under these conditions was determined using cyclic voltammetry. As expected, formation of a new phase was preceded by nucleation phenomena, which were particularly easy to monitor at solid Hg electrodes. The nucleation kinetics were studied using the chronoamperometric method. At very low temperatures, when the mobility of mercury atoms was restricted, the electrosorption of alkali metal ions on solid mercury electrodes was noted. Subsequent study allowed determination of the electrosorption parameters. The free energy of electrosorption is discussed in terms of interactions between alkali metals and mercury. The effect of crown ethers on the kinetics of alkali metal ion reduction was studied at both standard size and ultramicro-mercury electrodes in nonaqueous solutions using ultrafast cyclic voltammetry and ac voltammetry. The usefulness of ultrafast cyclic voltammetry with ultramicroelectrodes in measurements of the kinetics of amalgam formation was verified in a brief study of cadmium ion reduction. The mechanism of the complex reduction at mercury was analyzed based on the free energy changes before and after the activation state. In addition, the stoichiometry and formation constants of the crown ether/alkali metal complexes were determined using cyclic voltammetry. The mechanism of electroreduction of ammonium ions at mercury electrodes in non-aqueous media was analyzed.

  1. Statistical model of a flexible inextensible polymer chain: The effect of kinetic energy

    Science.gov (United States)

    Pergamenshchik, V. M.; Vozniak, A. B.

    2017-01-01

    Because of the holonomic constraints, the kinetic energy contribution in the partition function of an inextensible polymer chain is difficult to find, and it has been systematically ignored. We present the first thermodynamic calculation incorporating the kinetic energy of an inextensible polymer chain with the bending energy. To explore the effect of the translation-rotation degrees of freedom, we propose and solve a statistical model of a fully flexible chain of N +1 linked beads which, in the limit of smooth bending, is equivalent to the well-known wormlike chain model. The partition function with the kinetic and bending energies and correlations between orientations of any pair of links and velocities of any pair of beads are found. This solution is precise in the limits of small and large rigidity-to-temperature ratio b /T . The last exact solution is essential as even very "harmless" approximation results in loss of the important effects when the chain is very rigid. For very high b /T , the orientations of different links become fully correlated. Nevertheless, the chain does not go over into a hard rod even in the limit b /T →∞ : While the velocity correlation length diverges, the correlations themselves remain weak and tend to the value ∝T /(N +1 ). The N dependence of the partition function is essentially determined by the kinetic energy contribution. We demonstrate that to obtain the correct energy and entropy in a constrained system, the T derivative of the partition function has to be applied before integration over the constraint-setting variable.

  2. Removal of ammonium ion from aqueous solution using natural Turkish clinoptilolite

    International Nuclear Information System (INIS)

    Karadag, Dogan; Koc, Yunus; Turan, Mustafa; Armagan, Bulent

    2006-01-01

    A study on ion exchange kinetics and equilibrium isotherms of ammonium ion on natural Turkish clinoptilolite (zeolite) was conducted using a batch experiment technique. The effects of relevant parameters, such as temperature, contact time and initial ammonium (NH 4 + ) concentration were examined, respectively. The pseudo first-order, pseudo second-order kinetic models and intraparticle diffusion model were used to describe the kinetic data. The pseudo second-order kinetic model provided excellent kinetic data fitting (R 2 > 0.990) and intraparticle diffusion effects ammonium uptake. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms for ammonium uptake and the Langmuir model agrees very well with experimental data. Thermodynamic parameters such as change in free energy (ΔG 0 ), enthalpy (ΔH 0 ) and entropy (ΔS 0 ) were also determined. An examination of the thermodynamic parameters shows that the exchange of ammonium ion by clinoptilolite is a process occurring spontaneously and physical in nature at ambient conditions (25 deg. C). The process is also found to be exothermic. The results indicate that there is a significant potential for the natural Turkish clinoptilolite as an adsorbent material for ammonium removal from aqueous solutions

  3. Ion mass dependence for low energy channeling in single-wall nanotubes

    International Nuclear Information System (INIS)

    Zheng Liping; Zhu Zhiyuan; Li Yong; Zhu Dezhang; Xia Huihao

    2008-01-01

    An Monte Carlo (MC) simulation program has been used to study ion mass dependence for the low energy channeling of natural- and pseudo-Ar ions in single-wall nanotubes. The MC simulations show that the channeling critical angle Ψ C obeys the (E) -1/2 and the (M 1 ) -1/2 rules, where E is the incident energy and M 1 is the ion mass. The reason for this may be that the motion of the channeled (or de-channeled) ions should be correlated with both the incident energy E and the incident momentum (2M 1 E) 1/2 , in order to obey the conservation of energy and momentum

  4. Electron capture by multicharged ions at eV energies

    International Nuclear Information System (INIS)

    Havener, C.C.; Huq, M.S.; Meyer, F.W.; Phaneuf, R.A.

    1988-01-01

    A multicharged ion-atom merged-beams apparatus has been used in conjunction with the ORNL-ECR ion source to measure accurate absolute electron-capture cross sections in the energy range from below 1 eV/amu to 1500 eV/amu. Measurements for N/sup 3+,4+,5+/ /plus/ H(D) collisions indicate good agreement with available theoretical calculations. However, measurements with O 5+ /plus/ H(D) show an unexpected low-energy behavior which may be attributable to the ion-induced-dipole attraction between the reactants. Scaled Landau-Zener calculations presented here identify a transfer plus excitation channel which has the correct energy dependence at low energies. This finding suggest the need for a comprehensive coupled channel calculation which would include such product states. 25 refs., 8 figs

  5. Momentum and Kinetic Energy Before the Tackle in Rugby Union

    Science.gov (United States)

    Hendricks, Sharief; Karpul, David; Lambert, Mike

    2014-01-01

    Understanding the physical demands of a tackle in match situations is important for safe and effective training, developing equipment and research. Physical components such as momentum and kinetic energy, and it relationship to tackle outcome is not known. The aim of this study was to compare momenta between ball-carrier and tackler, level of play (elite, university and junior) and position (forwards vs. backs), and describe the relationship between ball-carrier and tackler mass, velocity and momentum and the tackle outcome. Also, report on the ball-carrier and tackler kinetic energy before contact and the estimated magnitude of impact (energy distributed between ball-carrier and tackler upon contact). Velocity over 0.5 seconds before contact was determined using a 2-dimensional scaled version of the field generated from a computer alogorithm. Body masses of players were obtained from their player profiles. Momentum and kinetic energy were subsequently calculated for 60 tackle events. Ball-carriers were heavier than the tacklers (ball-carrier 100 ± 14 kg vs. tackler 93 ± 11 kg, d = 0.52, p = 0.0041, n = 60). Ball-carriers as forwards had a significantly higher momentum than backs (forwards 563 ± 226 Kg.m.s-1 n = 31 vs. backs 438 ± 135 Kg.m.s-1, d = 0.63, p = 0.0012, n = 29). Tacklers dominated 57% of tackles and ball-carriers dominated 43% of tackles. Despite the ball-carrier having a mass advantage before contact more frequently than the tackler, momentum advantage and tackle dominance between the ball-carrier and tackler was proportionally similar. These findings may reflect a characteristic of the modern game of rugby where efficiently heavier players (particularly forwards) are tactically predetermined to carry the ball in contact. Key Points First study to quantify momentum, kinetic energy, and magnitude of impact in rugby tackles across different levels in matches without a device attached to a player. Physical components alone, of either ball-carrier or

  6. Momentum and kinetic energy before the tackle in rugby union.

    Science.gov (United States)

    Hendricks, Sharief; Karpul, David; Lambert, Mike

    2014-09-01

    Understanding the physical demands of a tackle in match situations is important for safe and effective training, developing equipment and research. Physical components such as momentum and kinetic energy, and it relationship to tackle outcome is not known. The aim of this study was to compare momenta between ball-carrier and tackler, level of play (elite, university and junior) and position (forwards vs. backs), and describe the relationship between ball-carrier and tackler mass, velocity and momentum and the tackle outcome. Also, report on the ball-carrier and tackler kinetic energy before contact and the estimated magnitude of impact (energy distributed between ball-carrier and tackler upon contact). Velocity over 0.5 seconds before contact was determined using a 2-dimensional scaled version of the field generated from a computer alogorithm. Body masses of players were obtained from their player profiles. Momentum and kinetic energy were subsequently calculated for 60 tackle events. Ball-carriers were heavier than the tacklers (ball-carrier 100 ± 14 kg vs. tackler 93 ± 11 kg, d = 0.52, p = 0.0041, n = 60). Ball-carriers as forwards had a significantly higher momentum than backs (forwards 563 ± 226 Kg(.)m(.)s(-1) n = 31 vs. backs 438 ± 135 Kg(.)m(.)s(-1), d = 0.63, p = 0.0012, n = 29). Tacklers dominated 57% of tackles and ball-carriers dominated 43% of tackles. Despite the ball-carrier having a mass advantage before contact more frequently than the tackler, momentum advantage and tackle dominance between the ball-carrier and tackler was proportionally similar. These findings may reflect a characteristic of the modern game of rugby where efficiently heavier players (particularly forwards) are tactically predetermined to carry the ball in contact. Key PointsFirst study to quantify momentum, kinetic energy, and magnitude of impact in rugby tackles across different levels in matches without a device attached to a player.Physical components alone, of either ball

  7. Damage growth in Si during self-ion irradiation: A study of ion effects over an extended energy range

    International Nuclear Information System (INIS)

    Holland, O.W.; El-Ghor, M.K.; White, C.W.

    1989-01-01

    Damage nucleation/growth in single-crystal Si during ion irradiation is discussed. For MeV ions, the rate of growth as well as the damage morphology are shown to vary widely along the track of the ion. This is attributed to a change in the dominant, defect-related reactions as the ion penetrates the crystal. The nature of these reactions were elucidated by studying the interaction of MeV ions with different types of defects. The defects were introduced into the Si crystal prior to high-energy irradiation by self-ion implantation at a medium energy (100 keV). Varied damage morphologies were produced by implanting different ion fluences. Electron microscopy and ion-channeling measurements, in conjunction with annealing studies, were used to characterize the damage. Subtle changes in the predamage morphology are shown to result in markedly different responses to the high-energy irradiation, ranging from complete annealing of the damage to rapid growth. These divergent responses occur over a narrow range of dose (2--3 times 10 14 cm -2 ) of the medium-energy ions; this range also marks a transition in the growth behavior of the damage during the predamage implantation. A model is proposed which accounts for these observations and provides insight into ion-induced growth of amorphous layers in Si and the role of the amorphous/crystalline interface in this process. 15 refs, 9 figs

  8. Kinetic energy factors in evaluation of athletes.

    Science.gov (United States)

    Jones, Jason N; Priest, Joe W; Marble, Daniel K

    2008-11-01

    It is established that speed and agility are critical attributes of sports performance. Performance timing of runs during agility course testing can be used to estimate acceleration, speed, or quickness. The authors of this research effort also report the energy of motion, or kinetic energy of the athlete, which considers not only the speed but also the mass of the athlete. An electronic timer was used to determine total run times as well as split performance times during a new 60-yd "run-shuttle" test. This newly designed agility test takes advantage of the technological capabilities of a laser timing device. Separate times for each of four run segments were recorded and converted to average speeds (m x s(-1)) as well as a quantitative factor of merit defined as the "K-factor." The purpose of this study was to describe the effects of training and to compare athletes and teams using measures of time, speed, and kinetic energy. Results of the analysis of total time on the 60-yd run-shuttle provided evidence of the effectiveness of the training programs. Split times of segments within the 60-yd run-shuttle provided information not available from conventional agility tests. Average speeds and K-factors identified discriminating characteristics of otherwise similar athletes. Our findings support the conclusion that training programs and athletic performance may be evaluated using the 60-yd run-shuttle with laser timer system. Coaches and trainers may find practical application of this technology for American football, soccer, basketball, baseball/softball, track and field, and field hockey.

  9. Nonlocal kinetic energy functionals by functional integration

    Science.gov (United States)

    Mi, Wenhui; Genova, Alessandro; Pavanello, Michele

    2018-05-01

    Since the seminal studies of Thomas and Fermi, researchers in the Density-Functional Theory (DFT) community are searching for accurate electron density functionals. Arguably, the toughest functional to approximate is the noninteracting kinetic energy, Ts[ρ], the subject of this work. The typical paradigm is to first approximate the energy functional and then take its functional derivative, δ/Ts[ρ ] δ ρ (r ) , yielding a potential that can be used in orbital-free DFT or subsystem DFT simulations. Here, this paradigm is challenged by constructing the potential from the second-functional derivative via functional integration. A new nonlocal functional for Ts[ρ] is prescribed [which we dub Mi-Genova-Pavanello (MGP)] having a density independent kernel. MGP is constructed to satisfy three exact conditions: (1) a nonzero "Kinetic electron" arising from a nonzero exchange hole; (2) the second functional derivative must reduce to the inverse Lindhard function in the limit of homogenous densities; (3) the potential is derived from functional integration of the second functional derivative. Pilot calculations show that MGP is capable of reproducing accurate equilibrium volumes, bulk moduli, total energy, and electron densities for metallic (body-centered cubic, face-centered cubic) and semiconducting (crystal diamond) phases of silicon as well as of III-V semiconductors. The MGP functional is found to be numerically stable typically reaching self-consistency within 12 iterations of a truncated Newton minimization algorithm. MGP's computational cost and memory requirements are low and comparable to the Wang-Teter nonlocal functional or any generalized gradient approximation functional.

  10. Low-energy ion beam extraction and transport: Experiment--computer comparison

    International Nuclear Information System (INIS)

    Spaedtke, P.; Brown, I.; Fojas, P.

    1994-01-01

    Ion beam formation at low energy (∼1 keV or so) is more difficult to accomplish than at high energy because of beam blowup by space-charge forces in the uncompensated region within the extractor, an effect which is yet more pronounced for heavy ions and for high beam current density. For the same reasons, the extracted ion beam is more strongly subject to space charge blowup than higher energy beams if it is not space-charge neutralized to a high degree. A version of vacuum arc ion source with an extractor that produces low-energy metal ion beams at relatively high current (∼0.5--10 kV at up to ∼100 mA) using a multi-aperture, accel--decel extractor configuration has been created. The experimentally observed beam extraction characteristics of this source is compared with those predicted using the AXCEL-INP code, and the implied downstream beam transport with theoretical expectations. It is concluded that the low-energy extractor performance is in reasonable agreement with the code, and that good downstream space charge neutralization is obtained. Here, the code and the experimental results are described, and the features that contribute to good low-energy performance are discussed

  11. Comparison between kinetic and fluid simulations of slab ion temperature gradient driven turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, H.; Watanabe, T.-H. [National Inst. for Fusion Science, Toki, Gifu (Japan); Horton, W. [University of Texas at Austin, Institute for Fusion Studies, Austin, Texas (United States)

    2002-10-01

    A detailed comparison between kinetic and fluid simulations of collisionless slab ion temperature gradient (ITG) driven turbulence is made. The nondissipative closure model (NCM) for linearly unstable modes, which is presented by Sugama, Watanabe, and Horton [Phys. Plasmas 8, 2617 (2001)], and the dissipative closure model by Hammett and Perkins (HP) [Phys. Rev. Lett. 64, 3019 (1990)] are used in separate fluid simulations. The validity of these closure models for quantitative prediction of the turbulent thermal transport is examined by comparing nonlinear results of the fluid simulations with those of the collisionless kinetic simulation of high accuracy. Simulation results show that, in the saturated turbulent state, the turbulent thermal diffusivity {chi} obtained from the HP model is significantly larger than the {chi} given by the NCM which is closer to {chi} measured in the kinetic simulation. Contrary to the dissipative form of the parallel heat flux closure relation assumed in the HP model, the NCM describes well the exact kinetic simulation, in which for some unstable wave numbers k, the imaginary part of the ratio of the parallel heat flux q{sub k} to the temperature fluctuation T{sub k} is a oscillatory function of time and sometimes takes positive values. The positive values of Im(q{sub k}/T{sub k}), imply the negative parallel heat diffusivity, correlate with the occasional inward heat flux occurring for the wave numbers k, and reduce the total {chi}. (author)

  12. Comparison between kinetic and fluid simulations of slab ion temperature gradient driven turbulence

    International Nuclear Information System (INIS)

    Sugama, H.; Watanabe, T.-H.; Horton, W.

    2002-10-01

    A detailed comparison between kinetic and fluid simulations of collisionless slab ion temperature gradient (ITG) driven turbulence is made. The nondissipative closure model (NCM) for linearly unstable modes, which is presented by Sugama, Watanabe, and Horton [Phys. Plasmas 8, 2617 (2001)], and the dissipative closure model by Hammett and Perkins (HP) [Phys. Rev. Lett. 64, 3019 (1990)] are used in separate fluid simulations. The validity of these closure models for quantitative prediction of the turbulent thermal transport is examined by comparing nonlinear results of the fluid simulations with those of the collisionless kinetic simulation of high accuracy. Simulation results show that, in the saturated turbulent state, the turbulent thermal diffusivity χ obtained from the HP model is significantly larger than the χ given by the NCM which is closer to χ measured in the kinetic simulation. Contrary to the dissipative form of the parallel heat flux closure relation assumed in the HP model, the NCM describes well the exact kinetic simulation, in which for some unstable wave numbers k, the imaginary part of the ratio of the parallel heat flux q k to the temperature fluctuation T k is a oscillatory function of time and sometimes takes positive values. The positive values of Im(q k /T k ), imply the negative parallel heat diffusivity, correlate with the occasional inward heat flux occurring for the wave numbers k, and reduce the total χ. (author)

  13. Bidirectional Energy Cascades and the Origin of Kinetic Alfvenic and Whistler Turbulence in the Solar Wind

    Science.gov (United States)

    Che, H.; Goldstein, M. L.; Vinas, A. F.

    2014-01-01

    The observed steep kinetic scale turbulence spectrum in the solar wind raises the question of how that turbulence originates. Observations of keV energetic electrons during solar quiet time suggest them as a possible source of free energy to drive kinetic turbulence. Using particle-in-cell simulations, we explore how the free energy released by an electron two-stream instability drives Weibel-like electromagnetic waves that excite wave-wave interactions. Consequently, both kinetic Alfvénic and whistler turbulence are excited that evolve through inverse and forward magnetic energy cascades.

  14. High energy metal ion implantation using 'Magis', a novel, broad-beam, Marx-generator-based ion source

    International Nuclear Information System (INIS)

    Anders, A.; Brown, I.G.; Dickinson, M.R.; MacGill, R.A.

    1996-08-01

    Ion energy of the beam formed by an ion source is proportional to extractor voltage and ion charge state. Increasing the voltage is difficult and costly for extraction voltage over 100 kV. Here we explore the possibility of increasing the charge states of metal ions to facilitate high-energy, broad beam ion implantation at a moderate voltage level. Strategies to enhance the ion charge state include operating in the regimes of high-current vacuum sparks and short pulses. Using a time-of-flight technique we have measured charge states as high as 7+ (73 kA vacuum spark discharge) and 4+ (14 kA short pulse arc discharge), both for copper, with the mean ion charge states about 6.0 and 2.5, respectively. Pulsed discharges can conveniently be driven by a modified Marx generator, allowing operation of ''Magis'' with a single power supply (at ground potential) for both plasma production and ion extraction

  15. Silver-Ion-Exchanged Nanostructured Zeolite X as Antibacterial Agent with Superior Ion Release Kinetics and Efficacy against Methicillin-Resistant Staphylococcus aureus.

    Science.gov (United States)

    Chen, Shaojiang; Popovich, John; Iannuzo, Natalie; Haydel, Shelley E; Seo, Dong-Kyun

    2017-11-15

    As antibiotic resistance continues to be a major public health problem, antimicrobial alternatives have become critically important. Nanostructured zeolites have been considered as an ideal host for improving popular antimicrobial silver-ion-exchanged zeolites, because with very short diffusion path lengths they offer advantages in ion diffusion and release over their conventional microsized zeolite counterparts. Herein, comprehensive studies are reported on materials characteristics, silver-ion release kinetics, and antibacterial properties of silver-ion-exchanged nanostructured zeolite X with comparisons to conventional microsized silver-ion-exchanged zeolite (∼2 μm) as a reference. The nanostructured zeolites are submicrometer-sized aggregates (100-700 nm) made up of primary zeolite particles with an average primary particle size of 24 nm. The silver-ion-exchanged nanostructured zeolite released twice the concentration of silver ions at a rate approximately three times faster than the reference. The material exhibited rapid antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) with minimum inhibitory concentration (MIC) values ranging from 4 to 16 μg/mL after 24 h exposure in various growth media and a minimum bactericidal concentration (MBC; >99.9% population reduction) of 1 μg/mL after 2 h in water. While high concentrations of silver-ion-exchanged nanostructured zeolite X were ineffective at reducing MRSA biofilm cell viability, efficacy increased at lower concentrations. In consideration of potential medical applications, cytotoxicity of the silver-ion-exchanged nanostructured zeolite X was also investigated. After 4 days of incubation, significant reduction in eukaryotic cell viability was observed only at concentrations 4-16-fold greater than the 24 h MIC, indicating low cytotoxicity of the material. Our results establish silver-ion-exchanged nanostructured zeolites as an effective antibacterial material against dangerous

  16. Nucleation of diindenoperylene and pentacene at thermal and hyperthermal incident kinetic energies

    Energy Technology Data Exchange (ETDEWEB)

    Kish, Edward R.; Desai, Tushar V.; Greer, Douglas R.; Engstrom, James R., E-mail: jre7@cornell.edu [School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853 (United States); Woll, Arthur R. [Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14853 (United States)

    2015-05-15

    The authors have examined the nucleation of diindenoperylene (DIP) on SiO{sub 2} employing primarily atomic force microscopy and focusing on the effect of incident kinetic energy employing both thermal and supersonic sources. For all incident kinetic energies examined (E{sub i} = 0.09–11.3 eV), the nucleation of DIP is homogeneous and the dependence of the maximum island density on the growth rate is described by a power law. A critical nucleus of approximately two molecules is implicated by our data. A re-examination of the nucleation of pentacene on SiO{sub 2} gives the same major result that the maximum island density is determined by the growth rate, and it is independent of the incident kinetic energy. These observations are readily understood by factoring in the size of the critical nucleus in each case, and the island density, which indicates that diffusive transport of molecules to the growing islands dominate the dynamics of growth in the submonolayer regime.

  17. On the neutralization of noble gas ions in low energy ion scattering

    International Nuclear Information System (INIS)

    Draxler, M.

    2003-04-01

    The set-up ACOLISSA has been set to operation. It was thoroughly tested and found to completely fulfill the requirements for the measurement of charge integrated and of ion TOF-LEIS spectra. Charge integrated scattering spectra in LEIS exhibit a surface peak in many experimental conditions. It was shown that the appearance of this peak is due to a reduced energy width of the contribution from the surface layer and partly due to a reduced energy loss in the surface layer as compared to deeper layers. In the regime of strong multiple scattering, both reasons reflect the fact, that scattering from surface atoms occurs practically exclusively by single binary collisions, while plural and multiple scattering set in in the subsurface layers. As a consequence, only the surface layer and to some extent also the second layer will contribute to the surface peak. Experiment as well as simulation show this behavior, so that other possible reasons for the appearance of a surface peak (e.g. channeling) can safely be ruled out. At high energies, when the multiple scattering half width angle is small, surface effects are mainly caused by electronic stopping and become small, as observed in both, experiment and simulation. In this regime, the energy spectrum is well described by the single scattering spectrum. From the present thesis one can draw the following conclusions concerning the neutralization of noble gas ions at metal surfaces: below the threshold for collision induced processes (CIN, CIR) Ε Εth), P+ is governed by local processes (collision induced neutralization and collision induced reionization) and by a non-local process (Auger neutralization), and thus depends on the energy as well as on vperp. From experiments like the one presented here, where the ion energy as well as the scattering geometry are varied, the process parameters of the neutralization can uniquely be determined for any system. These findings are generally valid and reveal the relevance of different

  18. Kinetic study of liquid-phase adsorptive removal of heavy metal ions by almond tree (Terminalia catappa L. leaves waste

    Directory of Open Access Journals (Sweden)

    Michael Horsfall Jnr

    2007-04-01

    Full Text Available The kinetic sorption of five metal ions – Al3+, Cr6+, Zn2+, Ag+ and Mn2+- from aqueous solution onto almond tree leaves (ATL waste in single component system has been studied. The experimental data was analyzed in terms of intraparticle diffusion and rate of adsorption, thus comparing transport mechanism and chemical sorption processes. The sorption rates based on the pseudo-second order rate constants for the five metal ions are 0.018 (Al3+, 0.016 (Cr6+, 0.023 (Zn2+, 0.021 (Ag+ and 0.022 (Mn2+ g/mg.min. The adsorption rates are rapid and within 180 min of agitation more than 85 percent of these metal ions has been removed from solution by the ATL waste biomass. The kinetic data suggest that the overall adsorption process is endothermic, and that the rate-limiting step is a surface diffusion controlled process. The results from this study have revealed that the ATL waste, which is hitherto an environmental nuisance, has the ability to adsorb metal ions from solution and the data are relevant for optimal design of wastewater treatment plants. The low cost and easy availability of ATL waste make potential industrial application a strong possibility.

  19. Comment on ‘Information hidden in the velocity distribution of ions and the exact kinetic Bohm criterion’

    Science.gov (United States)

    Mustafaev, A. S.; Sukhomlinov, V. S.; Timofeev, N. A.

    2018-03-01

    This Comment is devoted to some mathematical inaccuracies made by the authors of the paper ‘Information hidden in the velocity distribution of ions and the exact kinetic Bohm criterion’ (Plasma Sources Science and Technology 26 055003). In the Comment, we show that the diapason of plasma parameters for the validity of the theoretical results obtained by the authors was defined incorrectly; we made a more accurate definition of this diapason. As a result, we show that it is impossible to confirm or refute the feasibility of the Bohm kinetic criterion on the basis of the data of the cited paper.

  20. Diffusion kinetics of the glucose/glucose oxidase system in swift heavy ion track-based biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Dietmar, E-mail: fink@xanum.uam.mx [Nuclear Physics Institute, 25068 Řež (Czech Republic); Departamento de Fisica, Universidad Autónoma Metropolitana-Iztapalapa, PO Box 55-534, 09340 México, DF (Mexico); Vacik, Jiri; Hnatowicz, V. [Nuclear Physics Institute, 25068 Řež (Czech Republic); Muñoz Hernandez, G. [Departamento de Fisica, Universidad Autónoma Metropolitana-Iztapalapa, PO Box 55-534, 09340 México, DF (Mexico); Garcia Arrelano, H. [Departamento de Ciencias Ambientales, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Lerma, Av. de las Garzas No. 10, Col. El Panteón, Lerma de Villada, Municipio de Lerma, Estado de México CP 52005 (Mexico); Alfonta, Lital [Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 84105 (Israel); Kiv, Arik [Department of Materials Engineering, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 84105 (Israel)

    2017-05-01

    Highlights: • Application of swift heavy ion tracks in biosensing. • Obtaining yet unknown diffusion coefficients of organic matter across etched ion tracks. • Obtaining diffusion coefficients of organics in etched ion tracks of biosensors. • Comparison with Renkin’s equation to predict the effective etched track diameter in the given experiments. - Abstract: For understanding of the diffusion kinetics and their optimization in swift heavy ion track-based biosensors, recently a diffusion simulation was performed. This simulation aimed at yielding the degree of enrichment of the enzymatic reaction products in the highly confined space of the etched ion tracks. A bunch of curves was obtained for the description of such sensors that depend only on the ratio of the diffusion coefficient of the products to that of the analyte within the tracks. As hitherto none of these two diffusion coefficients is accurately known, the present work was undertaken. The results of this paper allow one to quantify the previous simulation and hence yield realistic predictions of glucose-based biosensors. At this occasion, also the influence of the etched track radius on the diffusion coefficients was measured and compared with earlier prediction.