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Sample records for cluster ions produced

  1. 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

  2. Comparison of Se and Te clusters produced by ion bombardment

    Directory of Open Access Journals (Sweden)

    Trzyna Małgorzata

    2017-01-01

    Full Text Available Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS. It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to ~ 1300 m/z. Local maxima or minima (magic numbers are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  3. Comparison of Se and Te clusters produced by ion bombardment

    Science.gov (United States)

    Trzyna, Małgorzata

    2017-01-01

    Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS). It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to 1300 m/z. Local maxima or minima (magic numbers) are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  4. Cluster ion beam facilities

    International Nuclear Information System (INIS)

    Popok, V.N.; Prasalovich, S.V.; Odzhaev, V.B.; Campbell, E.E.B.

    2001-01-01

    A brief state-of-the-art review in the field of cluster-surface interactions is presented. Ionised cluster beams could become a powerful and versatile tool for the modification and processing of surfaces as an alternative to ion implantation and ion assisted deposition. The main effects of cluster-surface collisions and possible applications of cluster ion beams are discussed. The outlooks of the Cluster Implantation and Deposition Apparatus (CIDA) being developed in Guteborg University are shown

  5. 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)

  6. Recombination of cluster ions

    Science.gov (United States)

    Johnsen, Rainer

    1993-01-01

    Some of our recent work on molecular band emissions from recombination of molecular dimer ions (N4(+) and CO(+) CO) is discussed. Much of the experimental work was done by Y. S. Cao; the results on N4(+) recombination have been published. A brief progress report is given on our ongoing measurements of neutral products of recombination using the flowing-afterglow Langmuir-probe technique in conjunction with laser-induced fluorescence.

  7. Observation of ions with energies above 100 keV produced by the interaction of a 60-fs laser pulse with clusters

    International Nuclear Information System (INIS)

    Dobosz, S.; Schmidt, M.; Perdrix, M.; Meynadier, P.; Gobert, O.; Normand, D.; Ellert, K.; Blenski, T.; Faenov, A.Ya.; Magunov, A.I.; Pikuz, T.A.; Skobelev, I.Yu.; Andreev, N.E.

    1999-01-01

    The x-ray spectra of a plasma generated by heating CO 2 and Ar clusters with high-intensity femtosecond laser pulses with q las ≅10 18 W/cm 2 are investigated. Spatially resolved x-ray spectra of a cluster plasma are obtained for the first time. Photoionization absorption is observed to influence the spectral line profiles. The recorded features of the x-ray emission spectra definitely indicate the existence of a large relative number of excited ions (≅10 -2 -10 -3 ) with energies of 0.1-1 MeV in such a plasma. Possible mechanisms underlying the acceleration of ions to high energies are discussed. It is shown that the experimental results can be attributed to the influence of ponderomotive forces in standing waves generated by the reflection of laser radiation from the clusters

  8. Cluster Ions and Atmospheric Processes

    Science.gov (United States)

    D'Auria, R.; Turco, R. P.

    We investigate the properties and possible roles of naturally occurring ions under at- mospheric conditions. Among other things, the formation of stable charged molecular clusters represents the initial stages of aerosol nucleation [e.g., Keesee and Castle- man, 1982], while the conversion of vapor to aggregates is the first step in certain atmospheric phase transitions [e.g. Hamill and Turco, 2000]. We analyze the stability and size distributions of common ionic clusters by solving the differential equations describing their growth and loss. The necessary reaction rate coefficients are deter- mined using kinetic and thermodynamic data. The latter are derived from direct labo- ratory measurements of equilibrium constants, from the classical charged liquid drop model applied to large aggregates (i.e., the Thomson model [Thomson, 1906]), and from quantum mechanical calculations of the thermodynamic potentials associated with the cluster structures. This approach allows us to characterize molecular clusters across the entire size range from true molecular species to larger aggregates exhibiting macroscopic behavior [D'Auria, 2001]. Cluster systems discussed in this talk include the proton hydrates (PHs) and nitrate-water and nitrate-nitric acid series [D'Auria and Turco, 2001]. These ions have frequently been detected in the stratosphere and tropo- sphere [e.g., Arnold et al., 1977; Viggiano and Arnold, 1981]. We show how the pro- posed hybrid cluster model can be extended to a wide range of ion systems, including non-proton hydrates (NPHs), mixed-ligand clusters such as nitrate-water-nitric acid and sulfate-sulfuric acid-water, as well as more exotic species containing ammonia, pyridine and other organic compounds found on ions [e.g., Eisele, 1988; Tanner and Eisele, 1991]. References: Arnold, F., D. Krankowsky and K. H. Marien, First mass spectrometric measurements of posi- tive ions in the stratosphere, Nature, 267, 30-32, 1977. D'Auria, R., A study of ionic

  9. Experimental investigations of hydrogen cluster ions

    International Nuclear Information System (INIS)

    Lumig, H.A. van.

    1978-01-01

    Experiments to obtain information about the structure and stability of small hydrogen cluster ions have been performed. Attenuation and fragmentation measurements are presented of hydrogen cluster ions colliding with nitrogen, argon, hydrogen and helium over fixed energy ranges. The total collision and differential fragmentation cross sections are tabulated. (C.F.)

  10. Some properties of ion and cluster plasma

    International Nuclear Information System (INIS)

    Gudzenko, L.I.; Derzhiev, V.I.; Yakovlenko, S.I.

    1982-01-01

    The aggregate of problems connected with the physics of ion and cluster plasma is qualitatively considered. Such a plasma can exist when a dense gas is ionized by a hard ionizer. The conditions for the formation of an ion plasma and the difference between its characteristics and those of an ordinary electron plasma are discussed; a solvated-ion model and the distribution of the clusters with respect to the number of solvated molecules are considered. The recombination rate of the positively and negatively charged clusters is roughly estimated. The parameters of a ball-lightning plasma are estimated on the basis of the cluster model

  11. METI/NEDO Projects on Cluster Ion Beam Process Technology

    International Nuclear Information System (INIS)

    Yamada, Isao; Matsuo, Jiro; Toyoda, Noriaki

    2003-01-01

    Since the initial study of gas cluster ion beams (GCIB) was started in the Ion Beam Engineering Experimental Laboratory of Kyoto University, more than 15 years have passed. Some of the results of that study have already been applied for industrial use. Unique characteristics of gas cluster ion bombardment have been found to offer potential for various other industrial applications. The impact of an accelerated cluster ion upon a target surface imparts very high energy densities into the impact area and produces non-linear effects that are not associated with the impacts of atomic ions. Among prospective applications for these effects are included shallow ion implantation, high rate sputtering, surface cleaning and smoothing, and low temperature thin film formation

  12. Properties of an ionised-cluster beam from a vaporised-cluster ion source

    International Nuclear Information System (INIS)

    Takagi, T.; Yamada, I.; Sasaki, A.

    1978-01-01

    A new type of ion source vaporised-metal cluster ion source, has been developed for deposition and epitaxy. A cluster consisting of 10 2 to 10 3 atoms coupled loosely together is formed by adiabatic expansion ejecting the vapour of materials into a high-vacuum region through the nozzle of a heated crucible. The clusters are ionised by electron bombardment and accelerated with neutral clusters toward a substrate. In this paper, mechanisms of cluster formation experimental results of the cluster size (atoms/cluster) and its distribution, and characteristics of the cluster ion beams are reported. The size is calculated from the kinetic equation E = (1/2)mNVsub(ej) 2 , where E is the cluster beam energy, Vsub(ej) is the ejection velocity, m is the mass of atom and N is the cluster size. The energy and the velocity of the cluster are measured by an electrostatic 127 0 energy analyser and a rotating disc system, respectively. The cluster size obtained for Ag is about 5 x 10 2 to 2 x 10 3 atoms. The retarding potential method is used to confirm the results for Ag. The same dependence on cluster size for metals such as Ag, Cu and Pb has been obtained in previous experiments. In the cluster state the cluster ion beam is easily produced by electron bombardment. About 50% of ionised clusters are obtained under typical operation conditions, because of the large ionisation cross sections of the clusters. To obtain a uniform spatial distribution, the ionising electrode system is also discussed. The new techniques are termed ionised-cluster beam deposition (ICBD) and epitaxy (ICBE). (author)

  13. Crater formation by single ions, cluster ions and ion "showers"

    CERN Document Server

    Djurabekova, Flyura; Timko, Helga; Nordlund, Kai; Calatroni, Sergio; Taborelli, Mauro; Wuensch, Walter

    2011-01-01

    The various craters formed by giant objects, macroscopic collisions and nanoscale impacts exhibit an intriguing resemblance in shapes. At the same time, the arc plasma built up in the presence of sufficiently high electric fields at close look causes very similar damage on the surfaces. Although the plasma–wall interaction is far from a single heavy ion impact over dense metal surfaces or the one of a cluster ion, the craters seen on metal surfaces after a plasma discharge make it possible to link this event to the known mechanisms of the crater formations. During the plasma discharge in a high electric field the surface is subject to high fluxes (~1025 cm-2s-1) of ions with roughly equal energies typically of the order of a few keV. To simulate such a process it is possible to use a cloud of ions of the same energy. In the present work we follow the effect of such a flux of ions impinging the surface in the ‘‘shower’’ manner, to find the transition between the different mechanisms of crater formati...

  14. Secondary ions produced from condensed rare gas targets under highly charged MeV/amu heavy ion bombardment

    International Nuclear Information System (INIS)

    Tawara, H.; Tonuma, T.; Kumagai, H.; Matsuo, T.

    1994-01-01

    Secondary ions produced from condensed rare gas targets are observed under MeV/amu, highly charged, heavy ion impact. The intensities of the observed cluster ions decrease smoothly as the cluster sizes become large but show some discontinuities at particular sizes of cluster ions. This seems to be closely related to the stabilities of cluster ion structures. It is also noted that very few doubly charged or practically no triply/higher charged ions have been observed, in sharp contrast to that of some condensed molecular targets. (orig.)

  15. CO2 laser photolysis of clustered ions, (1)

    International Nuclear Information System (INIS)

    Ikezoe, Yasumasa; Soga, Takeshi; Suzuki, Kazuya; Ohno, Shin-ichi.

    1990-09-01

    Vibrational excitation and the following decomposition of cluster ions by CO 2 laser photons are studied. Characteristics of the cluster ion and the CO 2 laser photon are summarized in their relation to the photolysis of cluster ions. An apparatus was installed, which is composed of (1) corona discharge-jet expansion section (formation of cluster ions), (2) CO 2 laser section (photolysis of cluster ions), and (3) mass spectrometer section. Experimental results of ammonia cluster ions were described. Effects of repeller voltage, shape of repellers, and adiabatic cooling are examined on the formation of ammonia cluster ions by corona discharge-jet expansion method. Collisional dissociation of cluster ions was observed at high repeller voltages. Size distribution of the ammonia cluster ion is discussed in connection with the temperature of cluster ions. Intensity of CO 2 laser was related to decomposition yield of cluster ions. (author)

  16. Ion-Ion Plasmas Produced by Electron Beams

    Science.gov (United States)

    Fernsler, R. F.; Leonhardt, D.; Walton, S. G.; Meger, R. A.

    2001-10-01

    The ability of plasmas to etch deep, small-scale features in materials is limited by localized charging of the features. The features charge because of the difference in electron and ion anisotropy, and thus one solution now being explored is to use ion-ion plasmas in place of electron-ion plasmas. Ion-ion plasmas are effectively electron-free and consist mainly of positive and negative ions. Since the two ion species behave similarly, localized charging is largely eliminated. However, the only way to produce ion-ion plasmas at low gas pressure is to convert electrons into negative ions through two-body attachment to neutrals. While the electron attachment rate is large at low electron temperatures (Te < 1 eV) in many of the halogen gases used for processing, these temperatures occur in most reactors only during the afterglow when the heating fields are turned off and the plasma is decaying. By contrast, Te is low nearly all the time in plasmas produced by electron beams, and therefore electron beams can potentially produce ion-ion plasmas continuously. The theory of ion-ion plasmas formed by pulsed electron beams is examined in this talk and compared with experimental results presented elsewhere [1]. Some general limitations of ion-ion plasmas, including relatively low flux levels, are discussed as well. [1] See the presentation by D. Leonhardt et al. at this conference.

  17. Investigations on carbon cluster formation in heavy ion irradiated polymers

    International Nuclear Information System (INIS)

    Tripathy, S.P.; Mishra, R.; Mawar, A.K.; Dwivedi, K.K.; Khathing, D.T.; Srivastava, A.; Avasthi, D.K.; Ghosh, S.; Fink, D.

    2000-01-01

    In polymers, the carbonaceous clusters are supposed to be responsible for the electrical conductivity. So, the irradiation of organic polymers namely polypropylene (8μ) and polyimide (50μ) by energetic heavy ions 28 Si and 58 Ni produce significant changes in the size of these clusters leading to the corresponding change in the band gap and other electrical properties as revealed by the UV-VIS spectroscopic examinations. (author)

  18. Vacancy supersaturations produced by high-energy ion implantation

    International Nuclear Information System (INIS)

    Venezia, V.C.; Eaglesham, D.J.; Jacobson, D.C.; Gossmann, H.J.

    1998-01-01

    A new technique for detecting the vacancy clusters produced by high-energy ion implantation into silicon is proposed and tested. This technique takes advantage of the fact that metal impurities, such as Au, are gettered near one-half of the projected range (1/2 R p ) of MeV implants. The vacancy clustered region produced by a 2 MeV Si + implant into silicon has been labeled with Au diffused in from the front surface. The trapped Au was detected by Rutherford backscattering spectrometry (RBS) to profile the vacancy clusters. Cross section transmission electron microscopy (XTEM) analysis shows that the Au in the region of vacancy clusters is in the form of precipitates. By annealing MeV implanted samples prior to introduction of the Au, changes in the defect concentration within the vacancy clustered region were monitored as a function of annealing conditions

  19. Cluster Ion Implantation in Graphite and Diamond

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2014-01-01

    Cluster ion beam technique is a versatile tool which can be used for controllable formation of nanosize objects as well as modification and processing of surfaces and shallow layers on an atomic scale. The current paper present an overview and analysis of data obtained on a few sets of graphite...... and diamond samples implanted by keV-energy size-selected cobalt and argon clusters. One of the emphases is put on pinning of metal clusters on graphite with a possibility of following selective etching of graphene layers. The other topic of concern is related to the development of scaling law for cluster...... implantation. Implantation of cobalt and argon clusters into two different allotropic forms of carbon, namely, graphite and diamond is analysed and compared in order to approach universal theory of cluster stopping in matter....

  20. Comparison of secondary ion emission yields for poly-tyrosine between cluster and heavy ion impacts

    International Nuclear Information System (INIS)

    Hirata, K.; Saitoh, Y.; Chiba, A.; Yamada, K.; Takahashi, Y.; Narumi, K.

    2010-01-01

    Emission yields of secondary ions necessary for the identification of poly-tyrosine were compared for incident ion impacts of energetic cluster ions (0.8 MeV C 8 + , 2.4 MeV C 8 + , and 4.0 MeV C 8 + ) and swift heavy monoatomic molybdenum ions (4.0 MeV Mo + and 14 MeV Mo 4+ ) with similar mass to that of the cluster by time-of-flight secondary ion mass analysis combined with secondary ion electric current measurements. The comparison revealed that (1) secondary ion emission yields per C 8 + impact increase with increasing incident energy within the energy range examined, (2) the 4.0 MeV C 8 + impact provides higher emission yields than the impact of the monoatomic Mo ion with the same incident energy (4.0 MeV Mo + ), and (3) the 2.4 MeV C 8 + impact exhibits comparable emission yields to that for the Mo ion impact with higher incident energy (14 MeV Mo 4+ ). Energetic cluster ion impacts effectively produce the characteristic secondary ions for poly-tyrosine, which is advantageous for highly sensitive amino acid detection in proteins using time-of-flight secondary ion mass analysis.

  1. Fullerene nanostructure design with cluster ion impacts

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vacík, Jiří; Naramoto, H.; Narumi, K.

    2009-01-01

    Roč. 483, - (2009), s. 479-483 ISSN 0925-8388 R&D Projects: GA AV ČR IAA200480702; GA AV ČR IAA400100701; GA AV ČR(CZ) KAN400480701 Institutional research plan: CEZ:AV0Z10480505 Keywords : fullerene films, clusters C60+ * cluster ion implantation * patterning Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.135, year: 2009

  2. Detection of gold cluster ions by ion-to-ion conversion using a CsI-converter

    International Nuclear Information System (INIS)

    Nguyen, V.-T.; Novilkov, A.C.; Obnorskii, V.V.

    1997-01-01

    Gold cluster ions in the m/z range of 10 4 -2 x 10 6 u were produced by bombarding a thin film of gold with 252 Cf-fission fragments. The gold covering a C-Al substrate formed islets having a mean diameter of 44 A. Their size- and mass-distribution was determined by means of electron microscopy. The main task was to measure the m/z distribution of the cluster ions ejected from the sample surface. For this purpose we built a time-of-flight (TOF) mass spectrometer, which could be used as a linear TOF instrument or, alternatively, as a tandem-TOF instrument being equipped with an ion-to-ion converter. Combining the results obtained in both modes, it turned out that the linear TOF instrument equipped with micro-channel plates had a mean detection efficiency for 20 keV cluster ions of about 40%. In the tandem mode, the cluster ions hit a CsI converter with energies of 40z keV (z = charge state), from where secondary ions - mainly Cs + and (CsI) n Cs + cluster ions - were ejected. These ions were used to measure the TOF spectrum of the gold cluster ions. The detection efficiency of the cluster ions was found to vary in the available mass range from 99.7% to 96.5%. The complete mass distribution between 4 x 10 4 and 4 x 10 6 u was determined and compared with the corresponding mass distribution of the gold islets covering the substrate. (orig.)

  3. Cluster ions and van der Waals molecules

    CERN Document Server

    Smirnov, Boris M

    1992-01-01

    This review discusses current ideas in the physics and chemistry of cluster ions and Van der Waals molecules as well as presenting numerical data on their parameters and the processes involving them. It is also a detailed reference on basic data relating to many species.

  4. Diffuse ions produced by electromagnetic ion beam instabilities

    International Nuclear Information System (INIS)

    Winske, D.; Leroy, M.M.

    1984-01-01

    The evolution of the electromagnetic ions beam instability driven by the reflected ion component backstreaming away from the earth's how shock into the foreshock region is studied by means computer simulation. The linear the quasi-linear states of the instability are found to be in good agreement with known results for the resonant model propagating parallel to the beam along the magnetic field and with theory developed in this paper for the nonresonant mode, which propagates antiparallel to the beam direction. The quasi-linear stage, which produces large amplitude 8Bapprox.B, sinusoidal transverse waves and ''intermediate'' ion distribution, is terminated by a nonlinear phase in which strongly nonlinear, compressive waves and ''diffuse'' ion distributions are produced. Additional processes by which the diffuse ions are accelerated to observed high energies are not addressed. The results are discussed in terms of the ion distributions and hydromagnetic waves observed in the foreshock of the earth's bow shock and of interplanetary shocks

  5. Scaling in patterns produces by cluster deposition

    DEFF Research Database (Denmark)

    Kyhle, Anders; Sørensen, Alexis Hammer; Oddershede, Lene

    1997-01-01

    Cluster deposition on flat substrates can lead to surprising patterns. This pattern formation can be related either to phenomena taking place at the substrate surface or to dynamics in the cluster beam. We describe the observation of a pattern of particles each being an aggregate of Cu clusters. ...

  6. Nonlinear damage effect in graphene synthesis by C-cluster ion implantation

    International Nuclear Information System (INIS)

    Zhang Rui; Zhang Zaodi; Wang Zesong; Wang Shixu; Wang Wei; Fu Dejun; Liu Jiarui

    2012-01-01

    We present few-layer graphene synthesis by negative carbon cluster ion implantation with C 1 , C 2 , and C 4 at energies below 20 keV. The small C-clusters were produced by a source of negative ion by cesium sputtering with medium beam current. We show that the nonlinear effect in cluster-induced damage is favorable for graphene precipitation compared with monomer carbon ions. The nonlinear damage effect in cluster ion implantation shows positive impact on disorder reduction, film uniformity, and the surface smoothness in graphene synthesis.

  7. Heavy-ion dominance near Cluster perigees

    Science.gov (United States)

    Ferradas, C. P.; Zhang, J.-C.; Kistler, L. M.; Spence, H. E.

    2015-12-01

    Time periods in which heavy ions dominate over H+ in the energy range of 1-40 keV were observed by the Cluster Ion Spectrometry (CIS)/COmposition DIstribution Function (CODIF) instrument onboard Cluster Spacecraft 4 at L values less than 4. The characteristic feature is a narrow flux peak at around 10 keV that extends into low L values, with He+ and/or O+ dominating. In the present work we perform a statistical study of these events and examine their temporal occurrence and spatial distribution. The observed features, both the narrow energy range and the heavy-ion dominance, can be interpreted using a model of ion drift from the plasma sheet, subject to charge exchange losses. The narrow energy range corresponds to the only energy range that has direct drift access from the plasma sheet during quiet times. The drift time to these locations from the plasma sheet is > 30 h, so that charge exchange has a significant impact on the population. We show that a simple drift/loss model can explain the dependence on L shell and MLT of these heavy-ion-dominant time periods.

  8. Nonthermal Particles and Radiation Produced by Cluster Merger Shocks

    Science.gov (United States)

    2003-09-10

    NONTHERMAL PARTICLES AND RADIATION PRODUCED BY CLUSTER MERGER SHOCKS Robert C. Berrington and Charles D. Dermer Naval Research Laboratory, Code 7653...of the merging cluster and is assumed to be constant as the shock propagates outward from the cluster center. In this paper , we model the cluster ...emission in the60–250 eV band for a number of clus- ters. These clusters include Virgo , Coma, Fornax, A2199, A1795, and A4059 (Lieu et al. 1996a, 1996b

  9. Biologically produced sulfur particles and polysulfide ions

    NARCIS (Netherlands)

    Kleinjan, W.E.

    2005-01-01

    This thesis deals with the effects of particles of biologically produced sulfur (or 'biosulfur') on a biotechnological process for the removal of hydrogen sulfide from gas streams. Particular emphasis is given to the role of polysulfide ions in such a process. These

  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. Range of plasma ions in cold cluster gases near the critical point

    International Nuclear Information System (INIS)

    Zhang, G.; Quevedo, H.J.; Bonasera, A.; Donovan, M.; Dyer, G.; Gaul, E.; Guardo, G.L.; Gulino, M.; La Cognata, M.; Lattuada, D.; Palmerini, S.; Pizzone, R.G.; Romano, S.; Smith, H.; Trippella, O.; Anzalone, A.; Spitaleri, C.; Ditmire, T.

    2017-01-01

    We measure the range of plasma ions in cold cluster gases by using the Petawatt laser at the University of Texas-Austin. The produced plasma propagated in all directions some hitting the cold cluster gas not illuminated by the laser. From the ratio of the measured ion distributions at different angles we can estimate the range of the ions in the cold cluster gas. It is much smaller than estimated using popular models, which take only into account the slowing down of charged particles in uniform matter. We discuss the ion range in systems prepared near a liquid–gas phase transition. - Highlights: • We present experimental results obtained at the UT Petawatt laser facility, Austin, TX. • The ion range is strongly modified for cluster gases as compared to its value in a homogeneous system. • Large fluctuations are found if the cluster gas is prepared near the liquid–gas phase transition region.

  12. Range of plasma ions in cold cluster gases near the critical point

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, G. [Cyclotron Institute, Texas A& M University, 77843 College Station, TX (United States); Quevedo, H.J. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Bonasera, A., E-mail: abonasera@comp.tamu.edu [Cyclotron Institute, Texas A& M University, 77843 College Station, TX (United States); Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Donovan, M.; Dyer, G.; Gaul, E. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Guardo, G.L. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Gulino, M. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Libera Universita' Kore, 94100 Enna (Italy); La Cognata, M.; Lattuada, D. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Palmerini, S. [Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Istituto Nazionale di Fisica Nucleare, Section of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Pizzone, R.G.; Romano, S. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Smith, H. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Trippella, O. [Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Istituto Nazionale di Fisica Nucleare, Section of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Anzalone, A.; Spitaleri, C. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Ditmire, T. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States)

    2017-05-18

    We measure the range of plasma ions in cold cluster gases by using the Petawatt laser at the University of Texas-Austin. The produced plasma propagated in all directions some hitting the cold cluster gas not illuminated by the laser. From the ratio of the measured ion distributions at different angles we can estimate the range of the ions in the cold cluster gas. It is much smaller than estimated using popular models, which take only into account the slowing down of charged particles in uniform matter. We discuss the ion range in systems prepared near a liquid–gas phase transition. - Highlights: • We present experimental results obtained at the UT Petawatt laser facility, Austin, TX. • The ion range is strongly modified for cluster gases as compared to its value in a homogeneous system. • Large fluctuations are found if the cluster gas is prepared near the liquid–gas phase transition region.

  13. Structure investigation of metal ions clustering in dehydrated gel using x-ray anomalous dispersion effect

    CERN Document Server

    Soejima, Y; Sugiyama, M; Annaka, M; Nakamura, A; Hiramatsu, N; Hara, K

    2003-01-01

    The structure of copper ion clusters in dehydrated N-isopropylacrylamide/sodium acrylate (NIPA/SA) gel has been studied by means of small angle X-ray scattering (SAXS) method. In order to distinguish the intensity scattered by Cu ions, the X-ray anomalous dispersion effect around the Cu K absorption edge has been coupled with SAXS. It is found that the dispersion effect dependent on the incident X-ray energy is remarkable only at the momentum transfer q = 0.031 A sup - sup 1 , where a SAXS peak is observed. The results indicate that copper ions form clusters in the dehydrated gel, and that the mean size of clusters is the same as that of SA clusters produced by microphase separation. It is therefore naturally presumed that copper ions are adsorbed into the SA molecules. On the basis of the presumption, a mechanism is proposed for microphase-separation and clustering of Cu ions.

  14. Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic metal Ions in Biology

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Nicholas B. [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics under identical instrument conditions. Carbon chain length also played a role in cluster ion formation. In Chapters 3 and 4, the effects of solvent types/ratios and various instrumental parameters on cluster ion formation were examined. It was found that instrument interface design also plays a critical role in the cluster ion distribution seen in the mass spectrum. In Chapter 5, ESI-MS was used to investigate toxic metal binding to the [Gln11]-amyloid β-protein fragment (1-16). Pb and Cd bound stronger than Zn, even in the presence of excess Zn. Hg bound weaker than Zn. There are endless options for future work on cluster ions. Any molecule that is poorly ionized in positive ion mode can potentially show an increase in ionization efficiency if an appropriate anion is used to produce a net negative charge. It is possible that drug protein or drug/DNA complexes can also be stabilized by adding counter-ions. This would preserve the solution characteristics of the complex in the gas phase. Once in the gas phase, CID could determine the drug binding location on the biomolecule. There are many research projects regarding toxic metals in biology that have yet to be investigated or even discovered. This is an area of research with an almost endless future because of the changing dynamics of biological systems. What is deemed safe today may show toxic effects in the future. Evolutionary changes in protein structures may render them more susceptible to toxic metal binding. As the understanding of toxicity evolves, so does the demand for new toxic metal research. New instrumentation designs and software make it possible to perform research that could not be done in the past. What was undetectable yesterday will

  15. Ion beam induced nanosized Ag metal clusters in glass

    International Nuclear Information System (INIS)

    Mahnke, H.-E.; Schattat, B.; Schubert-Bischoff, P.; Novakovic, N.

    2006-01-01

    Silver metal clusters have been formed in soda lime glass by high-energy heavy-ion irradiation at ISL. The metal cluster formation was detected with X-ray absorption spectroscopy (EXAFS) in fluorescence mode, and the shape of the clusters was imaged with transmission electron microscopy. While annealing in reducing atmosphere alone, leads to the formation of metal clusters in Ag-containing glasses, where the Ag was introduced by ion-exchange, such clusters are not very uniform in size and are randomly distributed over the Ag-containing glass volume. Irradiation with 600-MeV Au ions followed by annealing, however, results in clusters more uniform in size and arranged in chains parallel to the direction of the ion beam

  16. Research with stored ions produced using synchrotron radiation

    International Nuclear Information System (INIS)

    Church, D.A.; Kravis, S.D.; Meron, M.; Johnson, B.M.; Jones, K.W.; Sellin, I.A.; O, C.S.; Levin, J.C.; Short, R.T.

    1987-01-01

    A distribution of argon ion charge states has been produced by inner shell photoionization of argon atoms using x-ray synchrotron radiation. These ions were stored in a Penning ion trap at moderate to very low well depths, and analog-detected yielding narrow charge-to-mass spectrum linewidths. Estimates of ion densities indicated that ion-ion collisional energy transfer should be rapid, leading to thermalization. Measurements using variants of this novel stored, multi-charged ion gas are considered

  17. Indium tin oxide surface smoothing by gas cluster ion beam

    CERN Document Server

    Song, J H; Choi, W K

    2002-01-01

    CO sub 2 cluster ions are irradiated at the acceleration voltage of 25 kV to remove hillocks on indium tin oxide (ITO) surfaces and thus to attain highly smooth surfaces. CO sub 2 monomer ions are also bombarded on the ITO surfaces at the same acceleration voltage to compare sputtering phenomena. From the atomic force microscope results, the irradiation of monomer ions makes the hillocks sharper and the surfaces rougher from 1.31 to 1.6 nm in roughness. On the other hand, the irradiation of CO sub 2 cluster ions reduces the height of hillocks and planarize the ITO surfaces as smooth as 0.92 nm in roughness. This discrepancy could be explained by large lateral sputtering yield of the cluster ions and re-deposition of sputtered particles by the impact of the cluster ions on surfaces.

  18. Control of cluster ion sizes for efficient injection heating

    International Nuclear Information System (INIS)

    Enjoji, Hiroshi; Be, S.H.; Yano, Katsuki; Okamoto, Kosuke

    1976-01-01

    For heating of plasmas by injection of hydrogen cluster ions, the specific size (N/Z) approximately 10 2 molecules/charge is believed to be most desirable. A fundamental research to develop a practical method for tailoring large cluster ions into small suitable sizes has been carried out by using nitrogen cluster ions of the initial mean specific size (N/Z) 0 approximately 10 5 . The beam of neutral large clusters of total intensity 20 mAsub(eq) was led to an ionizer and then the large cluster ions are accelerated to 8.9 keV before entering the divider which disintegrates them into small fragments by multiple ionization. The mean specific size of disintegrated cluster ions (N/Z)' becomes smaller with increase in ionizing electron current of the divider. (N/Z)' becomes 10 3 approximately 10 4 at an electron current of 140 mA and an accelerating voltage of 680 V of the divider with its efficiency of 20 approximately 60%. Thus, the original large cluster ions are divided into small fragments of which the mean specific size is 1/20 approximately 1/100 of the initial value without much decrease in total intensity of the cluster ion beam

  19. 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)

  20. Production of strange clusters in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Dover, C.B.; Baltz, A.J.; Pang, Yang; Schlagel, T.J.; Kahana, S.H.

    1993-02-01

    We address a number of issues related to the production of strangeness in high energy heavy ion collisions, including the possibility that stable states of multi-strange hyperonic or quark matter might exist, and the prospects that such objects may be created and detected in the laboratory. We make use of events generated by the cascade code ARC to estimate the rapidity distribution dN/dy of strange clusters produced in Si+Au and Au+Au collisions at AGS energies. These calculations are performed in a simple coalescence model, which yields a consistent description of the strange cluster (d, 3 HE, 3 H, 4 He) production at these energies. If a doubly strange, weakly bound ΛΛ dibaryon exists, we find that it is produced rather copiously in Au+Au collisions, with dN/dy ∼0.1 at raid-rapidity. If one adds another non-strange or strange baryon to a cluster, the production rate decreases by roughly one or two orders of magnitude, respectively. For instance, we predict that the hypernucleus ΛΛ 6 He should have dN/dy ∼5 x 10 -6 for Au+Au central collisions. It should be possible to measure the successive Λ → pπ- weak decays of this object. We comment on the possibility that conventional multi-strange hypernuclei may serve as ''doorway states'' for the production of stable configurations of strange quark matter, if such states exist

  1. Irradiation effects of Ar cluster ion beams on Si substrates

    International Nuclear Information System (INIS)

    Ishii, Masahiro; Sugahara, Gaku; Takaoka, G.H.; Yamada, Isao

    1993-01-01

    Gas-cluster ion beams can be applied to new surface modification techniques such as surface cleaning, low damage sputtering and shallow junction formation. The effects of energetic Ar cluster impacts on solid surface were studied for cluster energies of 10-30keV. Irradiation effects were studied by RBS. For Si(111) substrates, irradiated with Ar ≥500 clusters to a dose of 1x10 15 ion/cm 2 at acceleration voltage 15kV, 2x10 14 atoms/cm 2 implanted Ar atoms were detected. In this case, the energy per cluster atom was smaller than 30eV; at this energy, no significant implantation occurs in the case of monomer ions. Ar cluster implantation into Si substrates occurred due to the high energy density irradiation. (author)

  2. Uses of laser optical pumping to produce polarized ion beams

    International Nuclear Information System (INIS)

    Anderson, L.W.

    1983-01-01

    Laser optical pumping can be used to produce polarized alkali atom beams or polarized alkali vapor targets. Polarized alkali atom beams can be converted into polarized alkali ion beams, and polarized alkali vapor targets can be used to produce polarized H - or 3 He - ion beams. In this paper the authors discuss how the polarized alkali atom beams and polarized alkali vapor targets are used to produce polarized ion beams with emphasis on the production of polarized negative ion beams

  3. Ion clusters, REB, and current sheath characteristics in focused discharges

    International Nuclear Information System (INIS)

    Bortolotti, A.; Brzosko, J.; DeChiara, P.; Kilic, H.; Mezzetti, F.; Nardi, V.; Powell, C.; Zeng, D.

    1990-01-01

    Small fluctuations in the current sheath characteristics (peak current density, FWHM of leading sheath, control parameters of sheath internal structure) are linked to wide fluctuations of ion and ion cluster emission from the pinch. Magnetic probe data are used for correlating variations of current sheath parameters with particle emission intensity, Z/M composition, particle energy spectrum. The emission of ion and ion clusters at 90 degrees from the axis of a plasma focus discharge is monitored simultaneously with the 0 degrees emission. The particle energy spectrum is analyzed with a Thomson (parabola) spectrometer (time resolution ∼ 1 nanosec). The cross-sectional structure of the REB at 180 degrees along the discharge axis is monitored via the deposition of collective-field accelerated ions on a target in the REB direction. Etched tracks of ion and ion clusters are in all cases recorded on CR-39 plates. Sharp peaks of the D + -ion spectrum at 90 degrees are found for E > 200 keV/unit charge in all focused discharges. These peaks are due to ion crossing of the azimuthal magnetic field of the pinch region, in a predominant ion cluster structure

  4. Pre-equilibrium (exciton) model and the heavy-ion reactions with cluster emission

    CERN Document Server

    Betak, E

    2015-01-01

    We bring the possibility to include the cluster emission into the statistical pre-equilibrium (exciton) model enlarged for considering also the heavy ion collisions. At this moment, the calculations have been done without treatment of angular momentum variables, but all the approach can be straightforwardly applied to heavy-ion reactions with cluster emission including the angular momentum variables. The direct motivation of this paper is a possibility of producing the superdeformed nuclei, which are easier to be detected in heavy-ion reactions than in those induced by light projectiles (nucleons, deuterons, $\\alpha$-particles).

  5. Gas cluster ion beam equipments for industrial applications

    International Nuclear Information System (INIS)

    Matsuo, J.; Takaoka, G.H.; Yamada, I.

    1995-01-01

    30 keV and 200 keV gas cluster ion beam equipments have been developed for industrial applications. A gas cluster source with a non-cooled nozzle was used for both the equipments. Sufficient monomer ion suppression was achieved by using an ExB filter and chromatic lenses mass filter with low extraction voltage. These equipments are suitable to be used for low-damage surface treatment of metals, insulators and semiconductors without heavy metal contamination. (orig.)

  6. The smoke ion source: A device for the generation of cluster ions via inert gas condensation

    International Nuclear Information System (INIS)

    McHugh, K.M.; Sarkas, H.W.; Eaton, J.G.; Bowen, K.H.; Westgate, C.R.

    1989-01-01

    We report the development of an ion source for generating intense, continuous beams of both positive and negative cluster ions. This device is the result of the marriage of the inert gas condensation method with techniques for injecting electrons directly into expanding jets. In the preliminary studies described here, we have observed cluster ion size distributions ranging from n=1-400 for Pb n + and Pb n - and from n=12-5700 for Li n - . (orig.)

  7. Plastic flow produced by single ion impacts on metals

    International Nuclear Information System (INIS)

    Birtcher, R. C.

    1998-01-01

    Single ion impacts have been observed using in situ transmission electron microscopy and video recording with a time resolution of 33 milliseconds. Gold was irradiated at 50 K and room temperature. Single ion impacts produce holes, modify existing holes, and extrude material into the initial specimen hole and holes formed by other ion impacts. The same behavior is observed at both temperatures. At both temperatures, ion impacts result in craters and ejected material. Ion impacts produce more small craters than large ones for all ion masses, while heavier mass ions produce more and larger craters than lighter mass ions. This comparison is affected by the ion energy. As the energy of an ion is increased, the probability for deposition near the surface decreases and fewer craters are formed. For a given ion mass, crater production depends on the probability for displacement cascade production in the near surface region. Crater and holes are stable at room temperature, however, ion impacts near an existing crater may cause flow of material into the crater either reshaping or annihilating it. Holes and craters result from the explosive outflow of material from the molten zone of near-surface cascades. The outflow may take the form of molten material, a solid lid or an ejected particle. The surface is a major perturbation on displacement cascades resulting from ion impacts

  8. Nanodevices produced with focussed ion beams

    International Nuclear Information System (INIS)

    Doetsch, U.; Wieck, A.D.

    1998-01-01

    In directly writing the 30 nm focus of a focussed Ga-ion beam (FIB) with an energy of 100 keV we define insulating lines in two-dimensional electronic layers in semiconductors. Ga ions act in GaAs and silicon as deep impurities or p-type doping, respectively. In this way the insulation by such written lines is due to lateral depletion within npn-like interfaces. In writing two FIB lines with a close spacing we define conducting channels between them. In applying a voltage of several Volts to the adjacent areas of the channel relative to it we can tune the effective width of the channel in the range of a few 100 nm to zero and obtain thus a one-dimensional field-effect-transistor-type structure. This transistor exhibits a pure lateral field effect and is thus topologically very different to current transistor concepts. Due to its particular geometry it is called in-plane-gate (IPG) transistor, since the gate and the channel are in the same plane. The fabrication of this type of transistor is thus completely maskless and does not require any alignment procedures since gate, source and drain are all written in the same writing process. Due to the computer-control of the beam deflection even more complex structures are just a question of software and do not need a set of specific masks or photoresist like in the classical lithography. The required line ion dose is of the order of 10 6 cm -1 which means that there are about 100 ions per μm implanted. For devices with maximum micron dimensions only a few hundred ions need thus to be implanted. (orig.)

  9. Lithium formate ion clusters formation during electrospray ionization: Evidence of magic number clusters by mass spectrometry and ab initio calculations

    International Nuclear Information System (INIS)

    Shukla, Anil; Bogdanov, Bogdan

    2015-01-01

    Small cationic and anionic clusters of lithium formate were generated by electrospray ionization and their fragmentations were studied by tandem mass spectrometry (collision-induced dissociation with N 2 ). Singly as well as multiply charged clusters were formed in both positive and negative ion modes with the general formulae, (HCOOLi) n Li + , (HCOOLi) n Li m m+ , (HCOOLi) n HCOO − , and (HCOOLi) n (HCOO) m m− . Several magic number cluster (MNC) ions were observed in both the positive and negative ion modes although more predominant in the positive ion mode with (HCOOLi) 3 Li + being the most abundant and stable cluster ion. Fragmentations of singly charged positive clusters proceed first by the loss of a dimer unit ((HCOOLi) 2 ) followed by the loss of monomer units (HCOOLi) although the former remains the dominant dissociation process. In the case of positive cluster ions, all fragmentations lead to the magic cluster (HCOOLi) 3 Li + as the most abundant fragment ion at higher collision energies which then fragments further to dimer and monomer ions at lower abundances. In the negative ion mode, however, singly charged clusters dissociated via sequential loss of monomer units. Multiply charged clusters in both positive and negative ion modes dissociated mainly via Coulomb repulsion. Quantum chemical calculations performed for smaller cluster ions showed that the trimer ion has a closed ring structure similar to the phenalenylium structure with three closed rings connected to the central lithium ion. Further additions of monomer units result in similar symmetric structures for hexamer and nonamer cluster ions. Thermochemical calculations show that trimer cluster ion is relatively more stable than neighboring cluster ions, supporting the experimental observation of a magic number cluster with enhanced stability

  10. Cluster observations of ion dispersion discontinuities in the polar cusp

    Science.gov (United States)

    Escoubet, C. P.; Berchem, J.; Pitout, F.; Richard, R. L.; Trattner, K. J.; Grison, B.; Taylor, M. G.; Masson, A.; Dunlop, M. W.; Dandouras, I. S.; Reme, H.; Fazakerley, A. N.

    2009-12-01

    The reconnection between the interplanetary magnetic field (IMF) and the Earth’s magnetic field is taking place at the magnetopause on magnetic field lines threading through the polar cusp. When the IMF is southward, reconnection occurs near the subsolar point, which is magnetically connected to the equatorward boundary of the polar cusp. Subsequently the ions injected through the reconnection point precipitate in the cusp and are dispersed poleward. If reconnection is continuous and operates at constant rate, the ion dispersion is smooth and continuous. On the other hand if the reconnection rate varies, we expect interruption in the dispersion forming energy steps or staircase. Similarly, multiple entries near the magnetopause could also produce steps at low or mid-altitude when a spacecraft is crossing subsequently the field lines originating from these multiple sources. In addition, motion of the magnetopause induced by solar wind pressure changes or erosion due to reconnection can also induce a motion of the polar cusp and a disruption of the ions dispersion observed by a spacecraft. Cluster with four spacecraft following each other in the mid-altitude cusp can be used to distinguish between these “temporal” and “spatial” effects. We will present a cusp crossing with two spacecraft, separated by around two minutes. The two spacecraft observed a very similar dispersion with a step in energy in its centre and two other dispersions poleward. We will show that the steps could be temporal (assuming that the time between two reconnection bursts corresponds to the time delay between the two spacecraft) but it would be a fortuitous coincidence. On the other hand the steps and the two poleward dispersions could be explained by spatial effects if we take into account the motion of the open-closed boundary between the two spacecraft crossings.

  11. The mobilies of chiral molecular cluster ions in He gas

    International Nuclear Information System (INIS)

    Saito, Kazuyuki; Matoba, Shiro; Koizumi, Tetsuo; Kojima, Takao M; Tanuma, Hajime; Shiromaru, Haruo

    2012-01-01

    We measured the mobilities of Li + -(2-butanol) and Li + -(limonene) ions in He gas at room temperature using a drift tube mass spectrometer. The zero field mobilities of Li + -(2-Butanol) and Li + -(Limonene) were much lower than the polarization limit, indicating that the geometric collision cross-sections between the cluster ions and He atom were larger than the cross-sections predicted by the presence of a polarization force alone.

  12. Proton-bound cluster ions in ion mobility spectrometry

    Science.gov (United States)

    Ewing, R. G.; Eiceman, G. A.; Stone, J. A.

    1999-01-01

    Gaseous oxygen and nitrogen bases, both singly and as binary mixtures, have been introduced into ion mobility spectrometers to study the appearance of protonated molecules, and proton-bound dimers and trimers. At ambient temperature it was possible to simultaneously observe, following the introduction of molecule A, comparable intensities of peaks ascribable to the reactant ion (H2O)nH+, the protonated molecule AH+ and AH+ H2O, and the symmetrical proton bound dimer A2H+. Mass spectral identification confirmed the identifications and also showed that the majority of the protonated molecules were hydrated and that the proton-bound dimers were hydrated to a much lesser extent. No significant peaks ascribable to proton-bound trimers were obtained no matter how high the sample concentration. Binary mixtures containing molecules A and B, in some cases gave not only the peaks unique to the individual compounds but also peaks due to asymmetrical proton bound dimers AHB+. Such ions were always present in the spectra of mixtures of oxygen bases but were not observed for several mixtures of oxygen and nitrogen bases. The dimers, which were not observable, notable for their low hydrogen bond strengths, must have decomposed in their passage from the ion source to the detector, i.e. in a time less than approximately 5 ms. When the temperature was lowered to -20 degrees C, trimers, both homogeneous and mixed, were observed with mixtures of alcohols. The importance of hydrogen bond energy, and hence operating temperature, in determining the degree of solvation of the ions that will be observed in an ion mobility spectrometer is stressed. The possibility is discussed that a displacement reaction involving ambient water plays a role in the dissociation.

  13. Energetics and Dynamics of Decaying Cluster Ions

    Czech Academy of Sciences Publication Activity Database

    Gluch, K.; Fedor, J.; Matt-Leubner, S.; Parajuli, R.; Mair, C.; Stamatovic, A.; Echt, O.; Lifshitz, C.; Harvey, J.; Hagelberg, F.; Herman, Zdeněk; Probst, M.; Scheier, P.; Märk, T. D.

    2003-01-01

    Roč. 24, 1/3 (2003), s. 131-136 ISSN 1434-6060 R&D Projects: GA ČR GA203/00/0632 Grant - others:European Commission(XE) Euroatom Institutional research plan: CEZ:AV0Z4040901 Keywords : surface-induced reactions * kinetics-energy release * polyatomic ions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.612, year: 2003

  14. High energy density in matter produced by heavy ion beams

    International Nuclear Information System (INIS)

    1987-08-01

    This annual report summarizes the results of research carried out in 1986 within the framework of the program 'High Energy Density in Matter Produced by Heavy Ion Beams' which is funded by the Federal Ministry for Research and Technology. Its initial motivation and its ultimate goal is the question whether inertial confinement can be achieved by intense beams of heavy ions. (orig./HSI)

  15. ION INJECTION AT QUASI-PARALLEL SHOCKS SEEN BY THE CLUSTER SPACECRAFT

    International Nuclear Information System (INIS)

    Johlander, A.; Vaivads, A.; Khotyaintsev, Yu. V.; Retinò, A.; Dandouras, I.

    2016-01-01

    Collisionless shocks in space plasma are known to be capable of accelerating ions to very high energies through diffusive shock acceleration (DSA). This process requires an injection of suprathermal ions, but the mechanisms producing such a suprathermal ion seed population are still not fully understood. We study acceleration of solar wind ions resulting from reflection off short large-amplitude magnetic structures (SLAMSs) in the quasi-parallel bow shock of Earth using in situ data from the four Cluster spacecraft. Nearly specularly reflected solar wind ions are observed just upstream of a SLAMS. The reflected ions are undergoing shock drift acceleration (SDA) and obtain energies higher than the solar wind energy upstream of the SLAMS. Our test particle simulations show that solar wind ions with lower energy are more likely to be reflected off the SLAMS, while high-energy ions pass through the SLAMS, which is consistent with the observations. The process of SDA at SLAMSs can provide an effective way of accelerating solar wind ions to suprathermal energies. Therefore, this could be a mechanism of ion injection into DSA in astrophysical plasmas

  16. Interaction of ion clusters with fusion plasmas: Scaling laws

    International Nuclear Information System (INIS)

    Arista, N.R.; Bringa, E.M.

    1997-01-01

    The interaction between large ion clusters or very intense ion beams with fusion plasma is studied using the dielectric function formalism with appropriate quantum corrections. The contributions from individual and collective modes to the energy loss are calculated. The general properties of the interference effects are characterized in terms of the relevant parameters, and simple scaling laws are obtained. In particular, the conditions for a maximum enhancement in the energy deposition are derived. The study provides a unified view and a general formulation of collective effects in the energy loss for low and high velocities of the beam particles. copyright 1997 The American Physical Society

  17. Ion implantation induced conducting nano-cluster formation in PPO

    International Nuclear Information System (INIS)

    Das, A.; Patnaik, A.; Ghosh, G.; Dhara, S.

    1997-01-01

    Conversion of polymers and non-polymeric organic molecules from insulating to semiconducting materials as an effect of energetic ion implantation is an established fact. Formation of nano-clusters enriched with carbonaceous materials are made responsible for the insulator-semiconductor transition. Conduction in these implanted materials is observed to follow variable range hopping (VRH) mechanism. Poly(2,6-dimethyl phenylene oxide) [PPO] compatible in various proportion with polystyrene is used as a high thermal resistant insulating polymer. PPO has been used for the first time in the ion implantation study

  18. Formation and metastable decomposition of unprotonated ammonia cluster ions upon femtosecond ionization

    International Nuclear Information System (INIS)

    Buzza, S.A.; Wei, S.; Purnell, J.; Castleman, A.W. Jr.

    1995-01-01

    The formation and metastable dissociation mechanism of unprotonated ammonia cluster ions, (NH 3 ) + n , produced by multiphoton ionization (MPI) at 624 nm and a nominal pulse width of 350 fs, are investigated through a reflectron time-of-flight (TOF) mass spectrometric technique. Detection of the unprotonated ions after femtosecond and nanosecond multiphoton ionization under various intensity conditions is explained. The role of the energy of the ionizing photons, and the observation of these ions after femtosecond MPI is examined. The formation of the unprotonated series is found to be a function of intensity in the case of ionization on the nanosecond time scale, but not so for the femtosecond time domain. The results can be explained in terms of ionization mechanisms and ionizing pulse durations. The findings of the present study suggest that the unprotonated ions are trapped behind the barrier to intracluster proton transfer and/or concomitant NH 2 loss. The studies of metastable decomposition also reveal that the unprotonated ammonia cluster ions dissociate in the field-free region of the TOF by losing an NH 2 radical rather than via the evaporative loss of NH 3 as occurs for protonated clusters. Additionally, isotopic investigations of the unimolecular decay reveal a strong dependence on the conditions of cluster formation. The cluster formation condition dependence of the unimolecular decay is further investigated by altering formation temperatures and observing the consequences reflected by changes in the spontaneous metastable decay rate constant. This is a unique example of a cluster system whose metastable dissociation does not obey an evaporative ensemble model

  19. Upgrading the Lyon cluster ion accelerator by a radiofrequency quadrupole

    International Nuclear Information System (INIS)

    Moser, H.O.; Schempp, A.

    1987-02-01

    The design is presented of an RFQ with variable final energy suitable to post-accelerate cluster ions from the Lyon electrostatic cluster-ion accelerator in the mass ranges from 1 to 25 μ and 1 to 50 μ to kinetic energies of 1.32-2.5 MeV and 2.64-5.0 MeV for cw and pulsed operation, respectively. Furthermore, a beam line is described which matches the electrostatically preaccelerated beam to the RFQ by use of electrostatic quadrupole triplets. When used without RFQ this beam line serves to improve beam parameters on the target, such as the particle flux density or beam divergence. The estimated costs of this project are about DM 345 000.- or FF 1 200 000.- without VAT. (orig.) [de

  20. Summary of Industry-Academia Collaboration Projects on Cluster Ion Beam Process Technology

    International Nuclear Information System (INIS)

    Yamada, Isao; Toyoda, Noriaki; Matsuo, Jiro

    2008-01-01

    Processes employing clusters of ions comprised of a few hundred to many thousand atoms are now being developed into a new field of ion beam technology. Cluster-surface collisions produce important non-linear effects which are being applied to shallow junction formation, to etching and smoothing of semiconductors, metals, and dielectrics, to assisted formation of thin films with nano-scale accuracy, and to other surface modification applications. In 2000, a four year R and D project for development of industrial technology began in Japan under funding from the New Energy and Industrial Technology Development Organization (NEDO). Subjects of the projects are in areas of equipment development, semiconductor surface processing, high accuracy surface processing and high-quality film formation. In 2002, another major cluster ion beam project which emphasized nano-technology applications has started under a contract from the Ministry of Economy and Technology for Industry (METI). This METI project involved development related to size-selected cluster ion beam equipment and processes, and development of GCIB processes for very high rate etching and for zero damage etching of magnetic materials and compound semiconductor materials. This paper describes summery of the results.

  1. Metal cluster cation reactions: Carbon monoxide association to Cu + n ions

    Science.gov (United States)

    Leuchtner, R. E.; Harms, A. C.; Castleman, A. W., Jr.

    1990-06-01

    Copper cluster cations (Cu+n,n=1-14) were produced in a laser vaporization/flow tube apparatus and equilibrated to room temperature. The association rate constants of carbon monoxide onto these ions were measured; low-pressure, termolecular behavior was observed for the smaller species while for clusters greater than Cu+7, the longer lifetimes due to the increased number of degrees of freedom leads to pressure independence (>0.3 Torr) of the effective bimolecular rates. Unimolecular decay theory (RRKM) is used to explain the overall trend and when intrinsic surface site reactivity is taken into account, excellent agreement with measured reactivity is obtained.

  2. Influence of residual Ar+ in Ar cluster ion beam for DLC film formation

    International Nuclear Information System (INIS)

    Kitagawa, Teruyuki; Miyauchi, Kazuya; Toyoda, Noriaki; Kanda, Kazuhiro; Ikeda, Tokumi; Tsubakino, Harushige; Matsuo, Jiro; Matsui, Shinji; Yamada, Isao

    2003-01-01

    In order to study the influences of residual Ar monomer ion (Ar + ) on sp 2 content and hardness of diamond like carbon (DLC) films formed by Ar cluster ion beam assisted deposition, Ar cluster ion, Ar + and their mixed ions (Ar cluster ion and Ar + ) bombardments were performed during evaporation of C 60 . From near edge X-ray absorption fine structure (NEXAFS) and Raman spectroscopy measurements, lower sp 2 content in the carbon films was obtained with Ar cluster ion bombardment than that with Ar + and mixed ion. Furthermore higher hardness and smooth surface were shown with Ar cluster ion bombardments. Therefore it was important to reduce Ar + in Ar cluster ion beams to obtain hard DLC films with flat surface

  3. Cluster observations of trapped ions interacting with magnetosheath mirror modes

    Directory of Open Access Journals (Sweden)

    J. Soucek

    2011-06-01

    Full Text Available Mirror modes are among the most intense low frequency plasma wave phenomena observed in the magnetosheaths of magnetized planets. They appear as large amplitude non-propagating fluctuations in the magnetic field magnitude and plasma density. These structures are widely accepted to represent a non-linear stage of the mirror instability, dominant in plasmas with large ion beta and a significant ion temperature anisotropy T⊥/T∥>1. It has long been recognized that the mirror instability both in the linear and non-linear stage is a kinetic process and that the behavior of resonant particles at small parallel velocities is crucial for its development and saturation. While the dynamics of the instability and the effect of trapped particles have been studied extensively in theoretical models and numerical simulations, only spurious observations of the trapped ions were published to date. In this work we used data from the Cluster spacecraft to perform the first detailed experimental study of ion velocity distribution associated with mirror mode oscillations. We show a conclusive evidence for the predicted cooling of resonant ions at small parallel velocities and heating of trapped ions at intermediate pitch angles.

  4. Visualization of DNA clustered damage induced by heavy ion exposure

    International Nuclear Information System (INIS)

    Tomita, M.; Yatagai, F.

    2003-01-01

    Full text: DNA double-strand breaks (DSBs) are the most lethal damage induced by ionizing radiations. Accelerated heavy-ions have been shown to induce DNA clustered damage, which is two or more DNA lesions induced within a few helical turns. Higher biological effectiveness of heavy-ions could be provided predominantly by induction of complex DNA clustered damage, which leads to non-repairable DSBs. DNA-dependent protein kinase (DNA-PK) is composed of catalytic subunit (DNA-PKcs) and DNA-binding heterodimer (Ku70 and Ku86). DNA-PK acts as a sensor of DSB during non-homologous end-joining (NHEJ), since DNA-PK is activated to bind to the ends of double-stranded DNA. On the other hand, NBS1 and histone H2AX are essential for DSB repair by homologous recombination (HR) in higher vertebrate cells. Here we report that phosphorylated H2AX at Ser139 (named γ-H2AX) and NBS1 form large undissolvable foci after exposure to accelerated Fe ions, while DNA-PKcs does not recognize DNA clustered damage. NBS1 and γ-H2AX colocalized with forming discrete foci after exposure to X-rays. At 0.5 h after Fe ion irradiation, NBS1 and γ-H2AX also formed discrete foci. However, at 3-8 h after Fe ion irradiation, highly localized large foci turned up, while small discrete foci disappeared. Large NBS1 and γ-H2AX foci were remained even 16 h after irradiation. DNA-PKcs recognized Ku-binding DSB and formed foci shortly after exposure to X-rays. DNA-PKcs foci were observed 0.5 h after 5 Gy of Fe ion irradiation and were almost completely disappeared up to 8 h. These results suggest that NBS1 and γ-H2AX can be utilized as molecular marker of DNA clustered damage, while DNA-PK selectively recognizes repairable DSBs by NHEJ

  5. Spatial distribution of ion energy related on electron density in a plasma channel generated in gas clusters by a femtosecond laser

    International Nuclear Information System (INIS)

    Nam, S. M.; Han, J. M.; Cha, Y. H.; Lee, Y. W.; Rhee, Y. J.; Cha, H. K.

    2008-01-01

    Neutron generation through Coulomb explosion of deuterium contained gas clusters is known as one of the very effective methods to produce fusion neutrons using a table top terawatt laser. The energy of ions produced through Coulomb explosions is very important factor to generate neutrons efficiently. Until the ion energy reaches around∼MeV level, the D D fusion reaction probability increases exponentially. The understanding of laser beam propagation and laser energy deposition in clusters is very important to improve neutron yields. As the laser beam propagates through clusters medium, laser energy is absorbed in clusters by ionization of molecules consisting clusters. When the backing pressure of gas increases, the average size of clusters increases and which results in higher energy absorption and earlier termination of laser propagation. We first installed a Michelson interferometer to view laser beam traces in a cluster plume and to measure spatial electron density profiles of a plasma channel which was produced by a laser beam. And then we measured the energy of ions distributed along the plasma channel with a translating slit to select ions from narrow parts of a plasma channel. In our experiments, methane gas was used to produce gas clusters at a room temperature and the energy distribution of proton ions for different gas backing pressure were measured by the time of flight method using dual micro channel plates. By comparing the distribution of ion energies and electron densities, we could understand the condition for effective laser energy delivery to clusters

  6. TEM study of amorphous alloys produced by ion implantation

    International Nuclear Information System (INIS)

    Johnson, E.; Grant, W.A.; Wohlenberg, P.; Hansen, P.; Chadderton, L.T.

    1978-01-01

    Ion implantation is a technique for introducing foreign elements into surface layers of solids. Ions, as a suitably accelerated beam, penetrate the surface, slow down by collisions with target atoms to produce a doped layer. This non-equilibrium technique can provide a wide range of alloys without the restrictions imposed by equilibrium phase diagrams. This paper reports on the production of some amorphous transition metal-metalloid alloys by implantation. Thinned foils of Ni, Fe and stainless steel were implanted at room temperature with Dy + and P + ions at doses between 10 13 - 10 17 ions/cm 2 at energies of 20 and 40 keV respectively. Transmission electron microscopy and selected area diffraction analysis were used to investigate the implanted specimens. Radial diffracted intensity measurements confirmed the presence of an amorphous implanted layer. The peak positions of the maxima are in good agreement with data for similar alloys produced by conventional techniques. Only certain ion/target combinations produce these amorphous layers. Implantations at doses lower than those needed for amorphization often result in formation of new crystalline phases such as an h.c.p. phase in nickel and a b.c.c. phase in stainless steel. (Auth.)

  7. Ion mixing and numerical simulation of different ions produced in the ECR ion source

    International Nuclear Information System (INIS)

    Shirkov, G.D.

    1996-01-01

    This paper is to continue theoretical investigations and numerical simulations in the physics of ECR ion sources within the CERN program on heavy ion acceleration. The gas (ion) mixing effect in ECR sources is considered here. It is shown that the addition of light ions to the ECR plasma has three different mechanisms to improve highly charged ion production: the increase of confinement time and charge state of highly ions as the result of ion cooling; the concentration of highly charged ions in the central region of the source with high energy and density of electrons; the increase of electron production rate and density of plasma. The numerical simulations of lead ion production in the mixture with different light ions and different heavy and intermediate ions in the mixture with oxygen, are carried out to predict the principal ECR source possibilities for LHC applications. 18 refs., 23 refs

  8. 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.

  9. Ion-neutral Clustering of Bile Acids in Electrospray Ionization Across UPLC Flow Regimes

    Science.gov (United States)

    Brophy, Patrick; Broeckling, Corey D.; Murphy, James; Prenni, Jessica E.

    2018-02-01

    Bile acid authentic standards were used as model compounds to quantitatively evaluate complex in-source phenomenon on a UPLC-ESI-TOF-MS operated in the negative mode. Three different diameter columns and a ceramic-based microfluidic separation device were utilized, allowing for detailed descriptions of bile acid behavior across a wide range of flow regimes and instantaneous concentrations. A custom processing algorithm based on correlation analysis was developed to group together all ion signals arising from a single compound; these grouped signals produce verified compound spectra for each bile acid at each on-column mass loading. Significant adduction was observed for all bile acids investigated under all flow regimes and across a wide range of bile acid concentrations. The distribution of bile acid containing clusters was found to depend on the specific bile acid species, solvent flow rate, and bile acid concentration. Relative abundancies of each cluster changed non-linearly with concentration. It was found that summing all MS level (low collisional energy) ions and ion-neutral adducts arising from a single compound improves linearity across the concentration range (0.125-5 ng on column) and increases the sensitivity of MS level quantification. The behavior of each cluster roughly follows simple equilibrium processes consistent with our understanding of electrospray ionization mechanisms and ion transport processes occurring in atmospheric pressure interfaces. [Figure not available: see fulltext.

  10. Clustered DNA damage induced by proton and heavy ion irradiation

    International Nuclear Information System (INIS)

    Davidkova, M.; Pachnerova Brabcova, K; Stepan, V.; Vysin, L.; Sihver, L.; Incerti, S.

    2014-01-01

    Ionizing radiation induces in DNA strand breaks, damaged bases and modified sugars, which accumulate with increasing density of ionizations in charged particle tracks. Compared to isolated DNA damage sites, the biological toxicity of damage clusters can be for living cells more severe. We investigated the clustered DNA damage induced by protons (30 MeV) and high LET radiation (C 290 MeV/u and Fe 500 MeV/u) in pBR322 plasmid DNA. To distinguish between direct and indirect pathways of radiation damage, the plasmid was irradiated in pure water or in aqueous solution of one of the three scavengers (coumarin-3-carboxylic acid, dimethylsulfoxide, and glycylglycine). The goal of the contribution is the analysis of determined types of DNA damage in dependence on radiation quality and related contribution of direct and indirect radiation effects. The yield of double strand breaks (DSB) induced in the DNA plasmid-scavenger system by heavy ion radiation was found to decrease with increasing scavenging capacity due to reaction with hydroxyl radical, linearly with high correlation coefficients. The yield of non-DSB clusters was found to occur twice as much as the DSB. Their decrease with increasing scavenging capacity had lower linear correlation coefficients. This indicates that the yield of non-DSB clusters depends on more factors, which are likely connected to the chemical properties of individual scavengers. (authors)

  11. Group IIB-VIA semiconductor oxide cluster ions

    Science.gov (United States)

    Jayasekharan, Thankan

    2018-05-01

    Metal oxide cluster ions, MnOm± (M = Zn, Cd) and HgnOm- of various stoichiometry have been generated from solid IIB-VIA semiconductor oxides targets, (ZnO(s), CdO(s), and HgO(s)) by using pulse laser desorption ionization time of flight mass spectrometry with a laser of λ = 355 nm. Analysis of mass spectral data indicates the formation of stoichiometric cluster ions viz., (ZnO)n=1-30+ and (CdO)n=1-40+ along with -O bound anions, (ZnO)n=1-30O-, (CdO)n=1-40O- and (HgO)n=1-36O- from their respective solids. Further, metal oxoanions such as ZnOn=2,3-, CdOn=2,3,6-, and HgOn=2,3,6,7- have also been noted signifying the higher coordination ability of both Cd and Hg with O/O2/O3 species.

  12. Intense pulsed sources of ions and electrons produced by lasers

    International Nuclear Information System (INIS)

    Bourrabier, G.; Consoli, T.; Slama, L.

    1966-11-01

    We describe a device for the acceleration of the plasma burst produced by focusing a laser beam into a metal target. We extract the electrons and the ions from the plasma. The maximum current is around 2000 amperes during few microseconds. The study of the effect of the kind of the target on the characteristics of the current shows the great importance of the initial conditions that is the ionisation potential of the target and the energy laser. (authors) [fr

  13. A search for quarks produced in heavy-ion interactions

    CERN Multimedia

    2002-01-01

    We propose to search for free fractional charges produced in 225~GeV/A heavy-ion collisions at the SPS. A tank of mercury placed in the NA38 beam stop will serve both as a production target and as an absorber to stop reaction products. Mercury from the tank will subsequently be distilled.\\\\ \\\\ This process will decrease the amount of mercury that has to be processed by a factor of about $10^{5}$. The concentrate will be searched for quarks using the proven SFSU automated Millikan apparatus.\\\\ \\\\ This experiment will be sensitive to about one quark produced per $2 \\times 10^{8}$ beam particles.

  14. Investigation of the alpha cluster model and the density matrix expansion in ion-ion collision

    International Nuclear Information System (INIS)

    Rashdan, M.B.M.

    1986-01-01

    This thesis deals with the investigation of the alpha cluster model (ACM) of brink and studies of the accuracy of the density matrix expansion (DME) approximation in deriving the real part of the ion-ion optical potential. the ACM is applied to calculate the inelastic 0 1 + →2 1 + charge form factor for electron scattering by 12 C to investigate the validity of this model for 12 C nucleus. it is found that the experimental curve can be fitted over the entire range of the momentum transfer by a generator - coordinate state for the 2 1 + state that consist of a superposition of two triangular ACM states with two different cluster separations and the same oscillator parameter

  15. High energy density in matter produced by heavy ion beams

    International Nuclear Information System (INIS)

    1989-07-01

    This Annual Report summarizes research activities carried out in 1988 in the framework of the government-funded program 'High Energy Density in Matter produced by Heavy Ion Beams'. It addresses fundamental problems of the generation of heavy ion beams and the investigation of hot dense plasmas produced by these beams. Its initial motivation and its long-term goal is the feasibility of inertial confinement fusion by intense heavy ion beams. Two outstanding events deserve to be mentioned explicity, the Heavy Ion Inertial Fusion Conference held in Darmstadt and organized by GSI end of June and the first heavy ion beam injected into the new SIS facility in November. The former event attracted more than hundred scientists for three days to the 4th Conference in this field. This symposium showed the impressive progress since the last conference in Washington two years ago. In particular the first beams in MBE-4 at LBL and results of beam plasma interaction experiments at GSI open new directions for future investigations. The ideas for non-Lionvillean injection into storage rings presented by Carlo Rubbia will bring the discussion of driver scenarios into a new stage. The latter event is a milestone for both machine and target experiments. It characterizes the beginning of the commissioning phase for the new SIS/ESR facility which will be ready for experiments at the end of this year. The commissioning of SIS is on schedule and first experiments can start at the beginning of 1990. A status report of the accelerator project is included. Theoretical activities were continued as in previous years, many of them providing guide lines for future experiments, in particular for the radiation transport aspects and for beam-plasma interaction. (orig.)

  16. Bi cluster-assembled interconnects produced using SU8 templates

    International Nuclear Information System (INIS)

    Partridge, J G; Matthewson, T; Brown, S A

    2007-01-01

    Bi clusters with an average diameter of 25 nm have been deposited from an inert gas aggregation source and assembled into thin-film interconnects which are formed between planar electrical contacts and supported on Si substrates passivated with Si 3 N 4 or thermally grown oxide. A layer of SU8 (a negative photoresist based on EPON SU-8 epoxy resin) is patterned using optical or electron-beam lithography, and it defines the position and dimensions of the cluster film. The conduction between the contacts is monitored throughout the deposition/assembly process, and subsequent I(V) characterization is performed in situ. Bi cluster-assembled interconnects have been fabricated with nanoscale widths and with up to 1:1 thickness:width aspect ratios. The conductivity of these interconnects has been increased, post-deposition, using a simple thermal annealing process

  17. Time-of-flight secondary ion mass spectrometry with energetic cluster ion impact ionization for highly sensitive chemical structure characterization

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, K., E-mail: k.hirata@aist.go.jp [National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Saitoh, Y.; Chiba, A.; Yamada, K.; Narumi, K. [Takasaki Advanced Radiation Research Institute (TARRI), Japan Atomic Energy Agency (JAEA), Takasaki, Gumma 370-1292 (Japan)

    2013-11-01

    Energetic cluster ions with energies of the order of sub MeV or greater were applied to time-of-flight (TOF) secondary ion (SI) mass spectrometry. This gave various advantages including enhancement of SIs required for chemical structure characterization and prevention of charging effects in SI mass spectra for organic targets. We report some characteristic features of TOF SI mass spectrometry using energetic cluster ion impact ionization and discuss two future applications of it.

  18. Dependence of energy per molecule on sputtering yields with reactive gas cluster ions

    International Nuclear Information System (INIS)

    Toyoda, Noriaki; Yamada, Isao

    2010-01-01

    Gas cluster ions show dense energy deposition on a target surface, which result in the enhancement of chemical reactions. In reactive sputtering with gas cluster ions, the energy per atom or molecule plays an important role. In this study, the average cluster size (N, the number of atoms or molecules in a cluster ion) was controlled; thereby the dependences of the energy per molecule on the sputtering yields of carbon by CO 2 cluster ions and that of Si by SF 6 /Ar mixed gas cluster ions were investigated. Large CO 2 cluster ions with energy per molecule of 1 eV showed high reactive sputtering yield of an amorphous carbon film. However, these ions did not cause the formation of large craters on a graphite surface. It is possible to achieve very low damage etching by controlling the energy per molecule of reactive cluster ions. Further, in the case of SF 6 /Ar mixed cluster ions, it was found that reactive sputtering was enhanced when a small amount of SF 6 gas (∼10%) was mixed with Ar. The reactive sputtering yield of Si by one SF 6 molecule linearly increased with the energy per molecule.

  19. Case Study of Ion Beams Observed By Cluster At Perigee

    Science.gov (United States)

    Sergeev, V.; Sauvaud, J.-A.; Perigee Beam Team

    During substorms the short beams of ions in the keV-to-tens keV energy range are injected into the auroral flux tubes from the magnetotail (sometimes extending up to >100 keV energy) carrying the information on the source distance, scale-size and temporal history of plasma acceleration. We present observations with the CLUSTER crossing inward the auroral zone flux tubes at ~4Re distance near its perigee during the substorm activity on February 14, 2001. The ion beams cover the same region (poleward half) of the auroral oval where the low-energy ions are extracted from the ionosphere, and where the small-scale transient transverse Alfven waves are observed which carry predominantly the downward parallel Poynting flux into the ionosphere. The multiple beams were basically confirmed to be the transient effects, although some effects including the (spatial) velocity filter and the parallel electric fields (im- posed by quasineutrality requirement) may complicate the interpretation. The gener- ation region of ion beams is not limited to most poleward, newly-reconnected flux tubes; the beam generation region could extend across magnetic field inward by as much as >100km (if mapped to the ionosphere). Surprising variety of injection dis- tances observed nearly simultaneously (ranging between >60 Re and ~10 Re) have been inferred when using the full available energy and time resolution, with shorter injection distances be possibly associated with the flow braking process. The beam multiplicity often displays the apparent ~3 min quasiperiodicity inherent to the basic dissipation process, it was not yet explained by any substorm theory.

  20. Case Report: Nodule Development From Subcapsular Aldosterone-Producing Cell Clusters Causes Hyperaldosteronism.

    Science.gov (United States)

    Nishimoto, Koshiro; Seki, Tsugio; Kurihara, Isao; Yokota, Kenichi; Omura, Masao; Nishikawa, Tetsuo; Shibata, Hirotaka; Kosaka, Takeo; Oya, Mototsugu; Suematsu, Makoto; Mukai, Kuniaki

    2016-01-01

    We previously reported that the human adrenal cortex remodels to form subcapsular aldosterone-producing cell clusters (APCCs). Some APCCs were recently found to carry aldosterone-producing adenoma (APA)-associated somatic mutations in ion channel/pump genes, which implied that APCCs produce aldosterone autonomously and are an origin of APA. However, there has been no report describing an APCC-to-APA transitional lesion. A histological examination revealed unilateral multiple adrenocortical micronodules in the adrenals of two patients with primary aldosteronism (PA). Based on immunohistochemistry for aldosterone synthase, some of the micronodules were identified as possible APCC-to-APA transitional lesions (pAATLs; a tentative term used in this manuscript), which consisted of a subcapsular APCC-like portion and an inner micro-APA-like (mAPA-like) portion without an apparent histological border. Genomic DNA samples prepared from pAATL histological sections were analyzed by next-generation sequencing for the known APA-associated mutations. The mAPA-like portions from two of the three large pAATLs examined harbored mutations (KCNJ5 [p.G151R] in pAATL 3 and ATP1A1 [p.L337M] in pAATL 7), whereas their corresponding APCC-like portions did not, suggesting their role in the formation of mAPA. Another lesion carried novel mutations in ATP1A1 (p.Ile322_Ile325del and p.Ile327Ser) in both the mAPA-like and APCC-like portions, thereby supporting these portions having a clonal origin. A novel aldosterone-producing pathology, pAATL that causes unilateral PA, was detected in the adrenals of two patients. Next-generation sequencing analyses of the large pAATLs suggested that the introduction of APA-associated mutations in the ion channel/pump genes may be involved in the development of mAPA from existing APCCs.

  1. Thin hydroxyapatite surface layers on titanium produced by ion implantation

    CERN Document Server

    Baumann, H; Bilger, G; Jones, D; Symietz, I

    2002-01-01

    In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (alpha,alpha) backscattering and the resonant nuclear reaction sup 1 H( sup 1 sup 5 N,alpha gamma) sup 1 sup 2 C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of m...

  2. Relative ion expansion velocity in laser-produced plasmas

    International Nuclear Information System (INIS)

    Goldsmith, S.; Moreno, J.C.; Griem, H.R.; Cohen, L.; Richardson, M.C.

    1988-01-01

    The spectra of highly ionized titanium, TiXIII through TiXXI, and CVI Lyman lines were excited in laser-produced plasmas. The plasma was produced by uniformly irradiating spherical glass microballoons coated with thin layers of titanium and parylene. The 24-beam Omega laser system produced short, 0.6 ns, and high intensity, 4 x 10 14 W/cm, 2 laser pulses at a wavelength of 351 nm. The measured wavelength for the 2p-3s TiXIII resonance lines had an average shift of +0.023 A relative to the CVI and TiXX spectral lines. No shift was found between the CVI, TiXIX, and TiXX lines. The shift is attributed to a Doppler effect, resulting from a difference of (2.6 +- 0.2) x 10 7 cm/s in the expansion velocities of TiXIX and TiXX ions compared to TiXIII ions

  3. Ionization of water clusters by fast Highly Charged Ions: Stability, fragmentation, energetics and charge mobility

    International Nuclear Information System (INIS)

    Legendre, S; Maisonny, R; Capron, M; Bernigaud, V; Cassimi, A; Gervais, B; Grandin, J-P; Huber, B A; Manil, B; Rousseau, P; Tarisien, M; Adoui, L; Lopez-Tarifa, P; AlcamI, M; MartIn, F; Politis, M-F; Penhoat, M A Herve du; Vuilleumier, R; Gaigeot, M-P; Tavernelli, I

    2009-01-01

    We study dissociative ionization of water clusters by impact of fast Ni ions. Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) is used to obtain information about stability, energetics and charge mobility of the ionized clusters. An unusual stability of the (H 2 O) 4 H ''+ ion is observed, which could be the signature of the so called ''Eigen'' structure in gas phase water clusters. High charge mobility, responsible for the formation of protonated water clusters that dominate the mass spectrum, is evidenced. These results are supported by CPMD and TDDFT simulations, which also reveal the mechanisms of such mobility.

  4. Particle modeling of transport of α-ray generated ion clusters in air

    International Nuclear Information System (INIS)

    Tong, Lizhu; Nanbu, Kenichi; Hirata, Yosuke; Izumi, Mikio; Miyamoto, Yasuaki; Yamaguchi, Hiromi

    2006-01-01

    A particle model is developed using the test-particle Monte Carlo method to study the transport properties of α-ray generated ion clusters in a flow of air. An efficient ion-molecule collision model is proposed to simulate the collisions between ion and air molecule. The simulations are performed for a steady state of ion transport in a circular pipe. In the steady state, generation of ions is balanced with such losses of ions as absorption of the measuring sensor or pipe wall and disappearance by positive-negative ion recombination. The calculated ion current to the measuring sensor agrees well with the previous measured data. (author)

  5. A study of defect cluster formation in vanadium by heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sekimura, Naoto; Shirao, Yasuyuki; Morishita, Kazunori [Tokyo Univ. (Japan)

    1996-10-01

    Formation of defect clusters in thin foils of vanadium was investigated by heavy ion irradiation. In the very thin region of the specimens less than 20 nm, vacancy clusters were formed under gold ion irradiation, while very few clusters were detected in the specimens irradiated with 200 and 400 keV self-ions up to 1 x 10{sup 16} ions/m{sup 2}. The density of vacancy clusters were found to be strongly dependent on ion energy. Only above the critical value of kinetic energy transfer density in vanadium, vacancy clusters are considered to be formed in the cascade damage from which interstitials can escape to the specimen surface in the very thin region. (author)

  6. Study of shallow junction formation by boron-containing cluster ion implantation of silicon and two-stage annealing

    Science.gov (United States)

    Lu, Xin-Ming

    Shallow junction formation made by low energy ion implantation and rapid thermal annealing is facing a major challenge for ULSI (ultra large scale integration) as the line width decreases down to the sub micrometer region. The issues include low beam current, the channeling effect in low energy ion implantation and TED (transient enhanced diffusion) during annealing after ion implantation. In this work, boron containing small cluster ions, such as GeB, SiB and SiB2, was generated by using the SNICS (source of negative ion by cesium sputtering) ion source to implant into Si substrates to form shallow junctions. The use of boron containing cluster ions effectively reduces the boron energy while keeping the energy of the cluster ion beam at a high level. At the same time, it reduces the channeling effect due to amorphization by co-implanted heavy atoms like Ge and Si. Cluster ions have been used to produce 0.65--2keV boron for low energy ion implantation. Two stage annealing, which is a combination of low temperature (550°C) preannealing and high temperature annealing (1000°C), was carried out to anneal the Si sample implanted by GeB, SiBn clusters. The key concept of two-step annealing, that is, the separation of crystal regrowth, point defects removal with dopant activation from dopant diffusion, is discussed in detail. The advantages of the two stage annealing include better lattice structure, better dopant activation and retarded boron diffusion. The junction depth of the two stage annealed GeB sample was only half that of the one-step annealed sample, indicating that TED was suppressed by two stage annealing. Junction depths as small as 30 nm have been achieved by two stage annealing of sample implanted with 5 x 10-4/cm2 of 5 keV GeB at 1000°C for 1 second. The samples were evaluated by SIMS (secondary ion mass spectrometry) profiling, TEM (transmission electron microscopy) and RBS (Rutherford Backscattering Spectrometry)/channeling. Cluster ion implantation

  7. Ligand induced structural isomerism in phosphine coordinated gold clusters revealed by ion mobility mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ligare, Marshall R.; Baker, Erin M.; Laskin, Julia; Johnson, Grant E.

    2017-01-01

    Structural isomerism in ligated gold clusters is revealed using electrospray ionization ion mobility spectrometry mass spectrometry. Phosphine ligated Au8 clusters are shown to adopt more “extended” type structures with increasing exchange of methyldiphenylphosphine (MePPh2) for triphenylphosphine (PPh3). These ligand-dependant structure-property relationships are critical to applications of clusters in catalysis.

  8. Electron impact ionization of size selected hydrogen clusters (H2)N: ion fragment and neutral size distributions.

    Science.gov (United States)

    Kornilov, Oleg; Toennies, J Peter

    2008-05-21

    Clusters consisting of normal H2 molecules, produced in a free jet expansion, are size selected by diffraction from a transmission nanograting prior to electron impact ionization. For each neutral cluster (H2)(N) (N=2-40), the relative intensities of the ion fragments Hn+ are measured with a mass spectrometer. H3+ is found to be the most abundant fragment up to N=17. With a further increase in N, the abundances of H3+, H5+, H7+, and H9+ first increase and, after passing through a maximum, approach each other. At N=40, they are about the same and more than a factor of 2 and 3 larger than for H11+ and H13+, respectively. For a given neutral cluster size, the intensities of the ion fragments follow a Poisson distribution. The fragmentation probabilities are used to determine the neutral cluster size distribution produced in the expansion at a source temperature of 30.1 K and a source pressure of 1.50 bar. The distribution shows no clear evidence of a magic number N=13 as predicted by theory and found in experiments with pure para-H2 clusters. The ion fragment distributions are also used to extract information on the internal energy distribution of the H3+ ions produced in the reaction H2+ + H2-->H3+ +H, which is initiated upon ionization of the cluster. The internal energy is assumed to be rapidly equilibrated and to determine the number of molecules subsequently evaporated. The internal energy distribution found in this way is in good agreement with data obtained in an earlier independent merged beam scattering experiment.

  9. Dynamics of Neutral Cluster Growth and Cluster Ion Fragmentation for Toluene/Water, Aniline/Argon, and 4-Fluorostyrene/Argon Clusters: Covariance Mapping of the Mass Spectral Data

    National Research Council Canada - National Science Library

    Foltin, M

    1998-01-01

    .... To explore sensitivity of the parent ion/fragment ion correlation coefficient to cluster fragmentation, correlation coefficients are measured as a function of ionization photon energy as thresholds...

  10. Cluster Observations of Ion Dispersions near the Exterior Cusp

    Science.gov (United States)

    Escoubet, C.; Grison, B.; Berchem, J.; Trattner, K. J.; Pitout, F.; Richard, R. L.; Taylor, M. G.; Laakso, H. E.; Masson, A.; Dunlop, M. W.; Dandouras, I. S.; Reme, H.; Fazakerley, A. N.; Daly, P. W.

    2013-12-01

    The cusps are the places where the Earth's magnetic field lines, connected to the inner side of the magnetopause, converge. It is therefore the place where signatures of processes occurring near the subsolar point, in the tail lobes, as well as near the dawn and dusk flanks are observed. The main process that injects solar wind plasma into the polar cusp is now generally accepted to be magnetic reconnection. Depending on the IMF direction, this process will take place equatorward (for IMF southward), poleward (for IMF northward) or on the side (for IMF azimuthal) of the cusp. We report a Cluster crossing on 5 January 2002 near the exterior cusp on the southern dusk side. The IMF was mainly azimuthal (IMF-By around -5 nT), the solar wind speed around 280 km/s and the density around 5 cm-3. The four Cluster spacecraft were still in the "magnetotail" configuration with two perfect tetrahedra of 2000 km around apogee and turning into an elongated configuration near the magnetopause. C4 was the first spacecraft to enter the cusp around 19:52:04 UT, followed by C2 at 19:52:35 UT, C1 at 19:54:24 UT and C3 at 20:13:15 UT. C4 and C1 observed two ion energy dispersions at 20:10 UT and 20:40 UT and C3 at 20:35 UT and 21:15 UT. We will investigate the origin of the injections forming the dispersions and if these can be explained by the reconnection between the interplanetary magnetic field and the Earth's magnetic field.

  11. Observation of dielectronic satellites in the K-spectrum of argon ions in plasma produced by femtosecond laser pulses

    International Nuclear Information System (INIS)

    Magunov, A.I.; Faenov, A.Ya.; Skobelev, I.Yu.; Pikuz, T.A.; Biemont, E.; Quinet, P.; Blasco, F.; Bonte, C.; Dorchies, F.; Caillaud, T.; Salin, F.; Stenz, C.

    2002-01-01

    The satellite structure of 1s2p 1,3 P 1 -1s 21 S 0 lines of the He-like argon ion in plasma produced by a 45-fs laser pulse in a gas-jet cluster target is measured with a high spectral resolution. Radiation transitions 2p → 1s from autoionizing states (AISs) are detected for ions ranging from Li-like to F-like. The spectrum observed is theoretically simulated with the use of the spectroscopic data for the AISs of multicharged ions obtained within the multiconfiguration relativistic Hartree-Fock method. Good agreement with experimental data is obtained when the main population channels of these states are taken into account for typical values of cluster-target plasma parameters

  12. Amorphous GaP produced by ion implantation

    International Nuclear Information System (INIS)

    Shimada, T.; Kato, Y.; Shiraki, Y.; Komatsubara, K.F.

    1976-01-01

    Two types of non-crystalline states ('disordered' and 'amorphous') of GaP were produced by using ion implantation and post annealing. A structural-phase-transition-like annealing behaviour from the 'disordered' state to the 'amorphous' state was observed. The ion dose dependence and the annealing behaviour of the atomic structure of GaP implanted with 200 keV -N + ions were studied by using electron diffraction, backscattering and volume change measurements. The electronic structure was also investigated by measuring optical absorption and electrical conductivity. The implanted layer gradually loses the crystalline order with the increase of the nitrogen dose. The optical absorption coefficient α and electric conductivity sigma of GaP crystals implanted with 200 keV -N + ions of 1 x 10 16 cm -2 were expressed as αhν = C(hν - E 0 )sup(n) and log sigma = A -BTsup(-1/4), respectively. Moreover, the volume of the implanted layer increased about three percent and the electron diffraction pattern was diffused halo whose intensity monotonically decreases along the radial direction. These results indicate that the as-implanted layer has neither a long range order or short range order ('disordered state'). In the sample implanted at 1 x 10 16 cm -2 , a structural phase-transition-like annealing stage was observed at around 400 0 C. That is, the optical absorption coefficient abruptly fell off from 6 x 10 4 to 7 x 10 3 cm -1 and the volume of the implanted layer decreased about 2% within an increase of less than 10 degrees in the anneal temperature. Moreover, the short range order of the lattice structure appeared in the electron diffraction pattern. According to the backscattering experiment, the heavily implanted GaP was still in the non-crystalline state even after annealing. These facts suggest that heavily implanted GaP, followed by annealing at around 400 0 C, is in the 'amorphous' state, although as-implanted GaP is not in the 'amorphous' state but in the

  13. Mixed clusters from the coexpansion of C2F6 and n2 in a pulsed, supersonic expansion cluster ion source and beam deflection time-of-flight mass spectrometer: A first application

    Science.gov (United States)

    Thompson, Steven D.

    The following topics are discussed: (1) cluster ion genesis; (2) cluster ion detection; (3) Ion source; (4) pulse valve; (5) e-gun; (6) Ion optics; (7) a first order model; and (8) a modified Bakker's model.

  14. XPS investigation of monatomic and cluster argon ion sputtering of tantalum pentoxide

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Robin, E-mail: r.simpson@surrey.ac.uk [The Surface Analysis Laboratory, Department of Mechanical Engineering Sciences, University of Surrey (United Kingdom); Thermo Scientific, East Grinstead (United Kingdom); White, Richard G. [Thermo Scientific, East Grinstead (United Kingdom); Watts, John F.; Baker, Mark A. [The Surface Analysis Laboratory, Department of Mechanical Engineering Sciences, University of Surrey (United Kingdom)

    2017-05-31

    Highlights: • Ion beam induced oxide reduction from monatomic and gas cluster ion beam exposure are compared. • Lower relative level of preferential sputtering is shown in gas cluster ion beam depth profiling. • A lack of “steady state” is observed in gas cluster ion beam depth profiles of tantalum pentoxide. • Possible mechanisms behind the observed results, including temperature effects are proposed. - Abstract: In recent years, gas cluster ion beams (GCIB) have become the cutting edge of ion beam technology to sputter etch organic materials in surface analysis. However, little is currently known on the ability of argon cluster ions (Ar{sub n}{sup +}) to etch metal oxides and other technologically important inorganic compounds and no depth profiles have previously been reported. In this work, XPS depth profiles through a certified (European standard BCR-261T) 30 nm thick Ta{sub 2}O{sub 5} layer grown on Ta foil using monatomic Ar{sup +} and Ar{sub 1000}{sup +} cluster ions have been performed at different incident energies. The preferential sputtering of oxygen induced using 6 keV Ar{sub 1000}{sup +} ions is lower relative to 3 keV and 500 eV Ar{sup +} ions. Ar{sup +} ions exhibit a steady state O/Ta ratio through the bulk oxide but Ar{sub 1000}{sup +} ions show a gradual decrease in the O/Ta ratio as a function of depth. The depth resolution and etch rate is substantially better for the monatomic beam compared to the cluster beam. Higher O concentrations are observed when the underlying Ta bulk metal is sputtered for the Ar{sub 1000}{sup +} profiles compared to the Ar{sup +} profiles.

  15. A theoretical investigation of the collective acceleration of cluster ions with accelerated potential waves

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi; Enjoji, Hiroshi; Kawaguchi, Motoichi; Noritake, Toshiya

    1984-01-01

    A theoretical treatment of the acceleration of cluster ions for additional heating of fusion plasma using the trapping effect in an accelerated potential wave is described. The conceptual design of the accelerator is the same as that by Enjoji, and the potential wave used is sinusoidal. For simplicity, collisions among cluster ions and the resulting breakups are neglected. The masses of the cluster ions are specified to range from 100 m sub(D) to 1000 m sub(D) (m sub(D): mass of a deuterium atom). Theoretical treatment is carried out only for the injection velocity which coincides with the phase velocity of the applied wave at the entrance of the accelerator. An equation describing the rate for successful acceleration of ions with a certain mass is deduced for the continuous injection of cluster ions. Computation for a typical mass distribution shows that more than 70% of the injected particles are effectively accelerated. (author)

  16. The quantitative analysis of silicon carbide surface smoothing by Ar and Xe cluster ions

    Science.gov (United States)

    Ieshkin, A. E.; Kireev, D. S.; Ermakov, Yu. A.; Trifonov, A. S.; Presnov, D. E.; Garshev, A. V.; Anufriev, Yu. V.; Prokhorova, I. G.; Krupenin, V. A.; Chernysh, V. S.

    2018-04-01

    The gas cluster ion beam technique was used for the silicon carbide crystal surface smoothing. The effect of processing by two inert cluster ions, argon and xenon, was quantitatively compared. While argon is a standard element for GCIB, results for xenon clusters were not reported yet. Scanning probe microscopy and high resolution transmission electron microscopy techniques were used for the analysis of the surface roughness and surface crystal layer quality. The gas cluster ion beam processing results in surface relief smoothing down to average roughness about 1 nm for both elements. It was shown that xenon as the working gas is more effective: sputtering rate for xenon clusters is 2.5 times higher than for argon at the same beam energy. High resolution transmission electron microscopy analysis of the surface defect layer gives values of 7 ± 2 nm and 8 ± 2 nm for treatment with argon and xenon clusters.

  17. Dependence of surface smoothing, sputtering and etching phenomena on cluster ion dosage

    CERN Document Server

    Song, J H; Choi, W K

    2002-01-01

    The dependence of surface smoothing and sputtering phenomena of Si (1 0 0) solid surfaces irradiated by CO sub 2 cluster ions on cluster-ion dosage was investigated using an atomic force microscope. The flux and total ion dosage of impinging cluster ions at the acceleration voltage of 50 kV were fixed at 10 sup 9 ions/cm sup 2 s and were scanned from 5x10 sup 1 sup 0 to 5x10 sup 1 sup 3 ions/cm sup 2 , respectively. The density of hillocks induced by cluster ion impact was gradually increased with the dosage up to 5x10 sup 1 sup 1 ions/cm sup 2 , which caused that the irradiated surface became rough from 0.4 to 1.24 nm in root-mean-square roughness (sigma sub r sub m sub s). At the boundary of the ion dosage of 10 sup 1 sup 2 ions/cm sup 2 , the density of the induced hillocks was decreased and sigma sub r sub m sub s was about 1.21 nm, not being deteriorated further. At the dosage of 5x10 sup 1 sup 3 ions/cm sup 2 , the induced hillocks completely disappeared and the surface became very flat as much as sigma...

  18. Ca-48 handling for a cyclotron ECR ion source to produce highly intense ion beams

    International Nuclear Information System (INIS)

    Lebedev, V.Ya.; Bogomolov, S.L.; Dmitriev, S.N.; Kutner, V.B.; Shamanin, A.N.; Yakushev, A.B.

    2002-01-01

    Production of highly intense ion beams of 48 Ca is one of the main tasks in experiments carried out within the framework of the synthesis of new superheavy elements. 48 Ca is very rare and expensive isotope, therefore there is necessity to reach the high intensity of ion beams of the isotope at a low consumption rate. Analysis and our preliminary experiments have showed that the best way of producing highly intense calcium ion beams is evaporation of metallic calcium in an ECR ion source. So we have developed a technique of metallic 48 Ca production by reducing CaO (this chemical form is available at the market with 40-80% of 48 Ca ) with aluminium powder. We used two tantalum crucibles: a larger, with a mixture of CaO + Al heated up to 1250 deg C, which was connected to the smaller (2 mm I.D. and 30 mm long) in which calcium vapour condensed. The temperature distribution in the small crucible was about 50 deg C at the bottom and about 500 deg C in the middle of the crucible. The pressure inside of the set-up was between 0.1 and 1 Pa. The production rate of metallic 48 Ca was 10-20 mg/h. The crucible with the condensed metallic Ca in argon atmosphere was transferred to the ECR-4M ion source, where it was inserted in a wired tubular oven and the calcium evaporation was controlled through the oven power supply. The application of metallic 48 Ca as the working substance for the ECR-4M ion source of the U-400 cyclotron of allowed us to approach a stable high intensity of 48 Ca ion beams: the intensities for the internal and external beams were 10 13 c -1 and 3.10 12 c -1 , respectively, at a consumption rate about 0.4 mg/h. A technique was developed for the reclamation of 48 Ca from the residue inside of the large crucible and from the inner parts of the ECR ion source. Extracting Ca from the inner parts of the ion source enabled us to save up to some 25% of the calcium used in the ECR ion source, so that the actual consumption rate was about 0.3 mg/h at the highest 48

  19. Angular distributions of particles sputtered from multicomponent targets with gas cluster ions

    Energy Technology Data Exchange (ETDEWEB)

    Ieshkin, A.E. [Faculty of Physics, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Ermakov, Yu.A., E-mail: yuriermak@yandex.ru [Skobeltsyn Nuclear Physics Research Institute, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Chernysh, V.S. [Faculty of Physics, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation)

    2015-07-01

    The experimental angular distributions of atoms sputtered from polycrystalline W, Cd and Ni based alloys with 10 keV Ar cluster ions are presented. RBS was used to analyze a material deposited on a collector. It has been found that the mechanism of sputtering, connected with elastic properties of materials, has a significant influence on the angular distributions of sputtered components. The effect of non-stoichiometric sputtering at different emission angles has been found for the alloys under cluster ion bombardment. Substantial smoothing of the surface relief was observed for all targets irradiated with cluster ions.

  20. Modification of semiconductor materials using laser-produced ion streams additionally accelerated in the electric fields

    International Nuclear Information System (INIS)

    Rosinski, M.; Badziak, B.; Parys, P.; Wolowski, J.; Pisarek, M.

    2009-01-01

    The laser-produced ion stream may be attractive for direct ultra-low-energy ion implantation in thin layer of semiconductor for modification of electrical and optical properties of semiconductor devices. Application of electrostatic fields for acceleration and formation of laser-generated ion stream enables to control the ion stream parameters in broad energy and current density ranges. It also permits to remove the useless laser-produced ions from the ion stream designed for implantation. For acceleration of ions produced with the use of a low fluence repetitive laser system (Nd:glass: 2 Hz, pulse duration: 3.5 ns, pulse energy:∼0.5 J, power density: 10 10 W/cm 2 ) in IPPLM the special electrostatic system has been prepared. The laser-produced ions passing through the diaphragm (a ring-shaped slit in the HV box) have been accelerated in the system of electrodes. The accelerating voltage up to 40 kV, the distance of the diaphragm from the target, the diaphragm diameter and the gap width were changed for choosing the desired parameters (namely the energy band of the implanted ions) of the ion stream. The characteristics of laser-produced Ge ion streams were determined with the use of precise ion diagnostic methods, namely: electrostatic ion energy analyser and various ion collectors. The laser-produced and post-accelerated Ge ions have been used for implantation into semiconductor materials for nanocrystal fabrication. The characteristics of implanted samples were measured using AES

  1. Multiple charge states of titanium ions in laser produced plasma

    Indian Academy of Sciences (India)

    An Nd:glass laser (KAMETRON) delivering 50 J energy (λ = 0.53 μm) in ... voltage on the deflection plates decides the energy (E/Z) of the charged particles to be ... of two ion groups viz fast ions (+22 to +12) and thermal ions (+11 to +1) as shown in ... ions survive the recombination losses in the early phase of expansion.

  2. Chemisorption on size-selected metal clusters: activation barriers and chemical reactions for deuterium and aluminum cluster ions

    International Nuclear Information System (INIS)

    Jarrold, M.F.; Bower, J.E.

    1988-01-01

    The authors describe a new approach to investigating chemisorption on size-selected metal clusters. This approach involves investigating the collision-energy dependence of chemisorption using low-energy ion beam techniques. The method provides a direct measure of the activation barrier for chemisorption and in some cases an estimate of the desorption energy as well. They describe the application of this technique to chemisorption of deuterium on size-selected aluminum clusters. The activation barriers increase with cluster size (from a little over 1 eV for Al 10 + to around 2 eV for Al 27 + ) and show significant odd-even oscillations. The activation barriers for the clusters with an odd number of atoms are larger than those for the even-numbered clusters. In addition to chemisorption of deuterium onto the clusters, chemical reactions were observed, often resulting in cluster fragmentation. The main products observed were Al/sub n-1/D + , Al/sub n-2/ + , and Al + for clusters with n + and Al/sub n-1/D + for the larger clusters

  3. X-ray emission spectra of the plasma produced by an ultrashort laser pulse in cluster targets

    International Nuclear Information System (INIS)

    Stenz, C; Bagnoud, V; Blasco, F; Roche, J R; Salin, F; Faenov, A Ya; Skobelev, I Yu; Magunov, A I; Pikuz, T A

    2000-01-01

    The first observation of x-ray emission spectra of multiply charged ions in the plasma produced by a 35-fs laser pulse with an intensity up to 10 17 W cm -2 in CO 2 and Kr gas jet targets is reported. The emission in the wavelength ranges of the 1snp-1s 2 (n=3-6) transitions of O VII ions and the Ly α line of O VIII ions, as well as of the (2s 1/2 2p 6 3p 3/2 ) 1 -2s 2 2p 6 1 S 0 and (2s 1/2 2p 6 3p 1/2 ) 1 -2s 2 2p 6 1 S 0 lines of Ne-like KrXXVII ions testifies that the highly ionised plasma is formed by collision processes in clusters. Modelling the shape of the spectral lines of oxygen ions by including the principal mechanisms of broadening and absorption in optically dense plasmas reveals that the main contribution to the time-integrated intensity is made by the plasma with the parameters N e =(2-20)x10 20 cm -3 and T e =100 - 115 eV. (interaction of laser radiation with matter. laser plasma)

  4. Differentiation of human-induced pluripotent stem cells into insulin-producing clusters.

    Science.gov (United States)

    Shaer, Anahita; Azarpira, Negar; Vahdati, Akbar; Karimi, Mohammad Hosein; Shariati, Mehrdad

    2015-02-01

    In diabetes mellitus type 1, beta cells are mostly destroyed; while in diabetes mellitus type 2, beta cells are reduced by 40% to 60%. We hope that soon, stem cells can be used in diabetes therapy via pancreatic beta cell replacement. Induced pluripotent stem cells are a kind of stem cell taken from an adult somatic cell by "stimulating" certain genes. These induced pluripotent stem cells may be a promising source of cell therapy. This study sought to produce isletlike clusters of insulin-producing cells taken from induced pluripotent stem cells. A human-induced pluripotent stem cell line was induced into isletlike clusters via a 4-step protocol, by adding insulin, transferrin, and selenium (ITS), N2, B27, fibroblast growth factor, and nicotinamide. During differentiation, expression of pancreatic β-cell genes was evaluated by reverse transcriptase-polymerase chain reaction; the morphologic changes of induced pluripotent stem cells toward isletlike clusters were observed by a light microscope. Dithizone staining was used to stain these isletlike clusters. Insulin produced by these clusters was evaluated by radio immunosorbent assay, and the secretion capacity was analyzed with a glucose challenge test. Differentiation was evaluated by analyzing the morphology, dithizone staining, real-time quantitative polymerase chain reaction, and immunocytochemistry. Gene expression of insulin, glucagon, PDX1, NGN3, PAX4, PAX6, NKX6.1, KIR6.2, and GLUT2 were documented by analyzing real-time quantitative polymerase chain reaction. Dithizone-stained cellular clusters were observed after 23 days. The isletlike clusters significantly produced insulin. The isletlike clusters could increase insulin secretion after a glucose challenge test. This work provides a model for studying the differentiation of human-induced pluripotent stem cells to insulin-producing cells.

  5. Reprint of: Negative carbon cluster ion beams: New evidence for the special nature of C60

    Science.gov (United States)

    Liu, Y.; O'brien, S. C.; Zhang, Q.; Heath, J. R.; Tittel, F. K.; Curl, R. F.; Kroto, H. W.; Smalley, R. E.

    2013-12-01

    Cold carbon cluster negative ions are formed by supersonic expansion of a plasma created at the nozzle of a supersonic cluster beam source by an excimer laser pulse. The observed distribution of mass peaks for the Cn- ions for n > 40 demonstrates that the evidence previously given for the special stability of neutral C60 and the existence of spheroidal carbon shells cannot be an artifact of the ionization conditions.

  6. High energy density in matter produced by heavy ion beams

    International Nuclear Information System (INIS)

    1986-05-01

    In this report the activities of the GSI Darmstadt (FRG) during 1985 concerning inertial confinement fusion by heavy ion beams. Short communications and abstracts are presented concerning a Z-pinch experiment, heavy ion pumped lasers and X-ray spectroscopy, the study of ion-ion collisions, a RFQ development and beam transport studies, accelerator theory, targets for SIS/ESR experiments, the rayleigh-Taylor instability, studies on the equation of state for matter under high pressure, as well as the development of computer codes. (HSI)

  7. Mass spectrometric probes of metal cluster distributions and metastable ion decay

    International Nuclear Information System (INIS)

    Parks, E.K.; Liu, K.; Cole, S.K.; Riley, S.J.

    1988-01-01

    The study of metal clusters has provided both an opportunity and a challenge to the application of mass spectrometry. These days the most often-used technique for cluster generation - laser vaporization - leads to extensive distributions of cluster sizes, from one to perhaps thousands of atoms, and most studies reported to date use excimer laser ionization and time-of-flight mass spectrometry for cluster detection. Our apparatus is a simple one-stage TOF design employing Wiley-McLauren spatial focusing and a one-meter drift tube. In a second apparatus employing a pulsed valve in the cluster source, we see asymmetric broadening of niobium cluster mass peaks under multiphoton ionization conditions, indicating metastable decay of parent cluster ions. Other studies of niobium clusters have shown no such asymmetric peaks. 2 figs

  8. The formation of magnetic silicide Fe{sub 3}Si clusters during ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Balakirev, N. [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Zhikharev, V., E-mail: valzhik@mail.ru [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Gumarov, G. [Zavoiskii Physico-Technical Institute of Russian Academy of Sciences, 10/7 Sibirskii trakt st., Kazan 420029 (Russian Federation)

    2014-05-01

    A simple two-dimensional model of the formation of magnetic silicide Fe{sub 3}Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

  9. The formation of magnetic silicide Fe3Si clusters during ion implantation

    Science.gov (United States)

    Balakirev, N.; Zhikharev, V.; Gumarov, G.

    2014-05-01

    A simple two-dimensional model of the formation of magnetic silicide Fe3Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

  10. The formation of magnetic silicide Fe3Si clusters during ion implantation

    International Nuclear Information System (INIS)

    Balakirev, N.; Zhikharev, V.; Gumarov, G.

    2014-01-01

    A simple two-dimensional model of the formation of magnetic silicide Fe 3 Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field

  11. Variation in the fumonisin biosynthetic gene cluster in fumonisin-producing and nonproducing black aspergilli.

    Science.gov (United States)

    Susca, Antonia; Proctor, Robert H; Butchko, Robert A E; Haidukowski, Miriam; Stea, Gaetano; Logrieco, Antonio; Moretti, Antonio

    2014-12-01

    The ability to produce fumonisin mycotoxins varies among members of the black aspergilli. Previously, analyses of selected genes in the fumonisin biosynthetic gene (fum) cluster in black aspergilli from California grapes indicated that fumonisin-nonproducing isolates of Aspergillus welwitschiae lack six fum genes, but nonproducing isolates of Aspergillus niger do not. In the current study, analyses of black aspergilli from grapes from the Mediterranean Basin indicate that the genomic context of the fum cluster is the same in isolates of A. niger and A. welwitschiae regardless of fumonisin-production ability and that full-length clusters occur in producing isolates of both species and nonproducing isolates of A. niger. In contrast, the cluster has undergone an eight-gene deletion in fumonisin-nonproducing isolates of A. welwitschiae. Phylogenetic analyses suggest each species consists of a mixed population of fumonisin-producing and nonproducing individuals, and that existence of both production phenotypes may provide a selective advantage to these species. Differences in gene content of fum cluster homologues and phylogenetic relationships of fum genes suggest that the mutation(s) responsible for the nonproduction phenotype differs, and therefore arose independently, in the two species. Partial fum cluster homologues were also identified in genome sequences of four other black Aspergillus species. Gene content of these partial clusters and phylogenetic relationships of fum sequences indicate that non-random partial deletion of the cluster has occurred multiple times among the species. This in turn suggests that an intact cluster and fumonisin production were once more widespread among black aspergilli. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Magic numbers and isotopic effect of ion clusters

    International Nuclear Information System (INIS)

    Wang Guanghou

    1989-04-01

    The magic numbers and isotopic effect as well as stable configurations in relation to the charge state of the clusters are discussed. Ionic (atomic) clusters are small atomic aggregates, a physical state between gas and solid states, and have many interesting properties, some of them are more or less similar to those in nuclei

  13. Smart darting diffusion Monte Carlo: Applications to lithium ion-Stockmayer clusters

    Science.gov (United States)

    Christensen, H. M.; Jake, L. C.; Curotto, E.

    2016-05-01

    In a recent investigation [K. Roberts et al., J. Chem. Phys. 136, 074104 (2012)], we have shown that, for a sufficiently complex potential, the Diffusion Monte Carlo (DMC) random walk can become quasiergodic, and we have introduced smart darting-like moves to improve the sampling. In this article, we systematically characterize the bias that smart darting moves introduce in the estimate of the ground state energy of a bosonic system. We then test a simple approach to eliminate completely such bias from the results. The approach is applied for the determination of the ground state of lithium ion-n-dipoles clusters in the n = 8-20 range. For these, the smart darting diffusion Monte Carlo simulations find the same ground state energy and mixed-distribution as the traditional approach for n simulations may produce a more reliable ground state mixed-distribution.

  14. 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

  15. Collision cascades and sputtering induced by larger cluster ions

    International Nuclear Information System (INIS)

    Sigmund, P.

    1988-01-01

    Recent experimental work on larger cluster impact on solid surfaces suggests large deviations from the standard case of additive sputter yields both in the nuclear and electronic stopping regime. The paper concentrates on elastic collision cascades. In addition to very pronounced spike effects, two phenomena are pointed out that are specific to cluster bombardment. Multiple hits of cluster atoms on one and the same target atom may result in recoil atoms that move faster than the maximum recoil speed for monomer bombardment at the same projectile speed. This effect is important when the atomic mass of a beam atom is less than that of a target atom, M 1 2 . In the opposite case, M 1 >> M 2 , collisions between beam particles may accelerate some beam particles and slow down others. Some consequences are mentioned. Remarks on the nuclear stopping power of larger clusters and on electronic sputtering by cluster bombardment conclude the paper. 38 refs., 2 figs

  16. Observation of the inhomogeneous spatial distribution of MeV ions accelerated by the hydrodynamic ambipolar expansion of clusters

    International Nuclear Information System (INIS)

    Kanasaki, Masato; Jinno, Satoshi; Sakaki, Hironao; Faenov, Anatoly Ya.; Pikuz, Tatiana A.; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Kando, Masaki; Sugiyama, Akira; Kondo, Kiminori; Matsui, Ryutaro; Kishimoto, Yasuaki; Morishima, Kunihiro; Watanabe, Yukinobu; Scullion, Clare; Smyth, Ashley G.; Alejo, Aaron; Doria, Domenico; Kar, Satyabrata; Borghesi, Marco

    2015-01-01

    An inhomogeneous spatial distribution of laser accelerated carbon/oxygen ions produced via the hydrodynamic ambipolar expansion of CO_2 clusters has been measured by using CR-39 detectors. An inhomogeneous etch pits spatial distribution has appeared on the etched CR-39 detector installed on the laser propagation direction, while homogeneous ones are appeared on those installed at 45° and 90° from the laser propagation direction. From the range of ions in CR-39 obtained by using the multi-step etching technique, the averaged energies of carbon/oxygen ions for all directions are determined as 0.78 ± 0.09 MeV/n. The number of ions in the laser propagation direction is about 1.5 times larger than those in other directions. The inhomogeneous etch pits spatial distribution in the laser propagation direction could originate from an ion beam collimation and modulation by the effect of electromagnetic structures created in the laser plasma. - Highlights: • A spatial distribution of ions due to hydrodynamic ambipolar expansion is measured. • The homogeneous ion energy distribution of 0.78 ± 0.09 MeV/n is measured by CR-39. • The number of ions in the laser axis is about 1.5 times larger than other directions.

  17. Reference masses for precision mass spectrometry design and implementation of a Pierce geometry to the cluster Ion source at ISOLTRAP

    CERN Document Server

    Lommen, Jonathan

    At the mass spectrometer ISOLTRAP carbon clusters ($^{12}$Cn, 1$\\leqslant$n$\\leqslant$25) are provided as reference masses, which are of particular importance in higher mass ranges (m $\\geqslant$ 200u). In this mass range the measurlment uncertainty is increasingly dominated by the difference of the reference mass and the mass of the ion of interest. Using carbon clusters instead of the common $^{133}$Cs ions, this difference decreases. The carbon clusters are produced in a laser ion source which has been improved in the frame of this thesis. The fluctuations of the count rate have been investigated as a function of the laser energy. Furthermore, the energy density at the target has been increased by implementation of a telescope into the laser beam line, which leads to a more narrow energy distribution of the ions. Through the exact adjustment of timing and length of a pulsed cavity an energy range with constant count rate could be selected. In order to provide ideal starting conditions during and after the ...

  18. Cluster secondary ion mass spectrometry microscope mode mass spectrometry imaging.

    Science.gov (United States)

    Kiss, András; Smith, Donald F; Jungmann, Julia H; Heeren, Ron M A

    2013-12-30

    Microscope mode imaging for secondary ion mass spectrometry is a technique with the promise of simultaneous high spatial resolution and high-speed imaging of biomolecules from complex surfaces. Technological developments such as new position-sensitive detectors, in combination with polyatomic primary ion sources, are required to exploit the full potential of microscope mode mass spectrometry imaging, i.e. to efficiently push the limits of ultra-high spatial resolution, sample throughput and sensitivity. In this work, a C60 primary source was combined with a commercial mass microscope for microscope mode secondary ion mass spectrometry imaging. The detector setup is a pixelated detector from the Medipix/Timepix family with high-voltage post-acceleration capabilities. The system's mass spectral and imaging performance is tested with various benchmark samples and thin tissue sections. The high secondary ion yield (with respect to 'traditional' monatomic primary ion sources) of the C60 primary ion source and the increased sensitivity of the high voltage detector setup improve microscope mode secondary ion mass spectrometry imaging. The analysis time and the signal-to-noise ratio are improved compared with other microscope mode imaging systems, all at high spatial resolution. We have demonstrated the unique capabilities of a C60 ion microscope with a Timepix detector for high spatial resolution microscope mode secondary ion mass spectrometry imaging. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Amorphous molecular junctions produced by ion irradiation on carbon nanotubes

    International Nuclear Information System (INIS)

    Wang Zhenxia; Yu Liping; Zhang Wei; Ding Yinfeng; Li Yulan; Han Jiaguang; Zhu Zhiyuan; Xu Hongjie; He Guowei; Chen Yi; Hu Gang

    2004-01-01

    Experiments and molecular dynamics have demonstrated that electron irradiation could create molecular junctions between crossed single-wall carbon nanotubes. Recently molecular dynamics computation predicted that ion irradiation could also join single-walled carbon nanotubes. Employing carbon ion irradiation on multi-walled carbon nanotubes, we find that these nanotubes evolve into amorphous carbon nanowires, more importantly, during the process of which various molecular junctions of amorphous nanowires are formed by welding from crossed carbon nanotubes. It demonstrates that ion-beam irradiation could be an effective way not only for the welding of nanotubes but also for the formation of nanowire junctions

  20. Structure and reactivity of molybdenum oxide cluster ions in the gas phase

    International Nuclear Information System (INIS)

    Goncharov, V.B.; Fialko, E.F.

    2002-01-01

    A set of cluster ions of molybdenum oxides Mo x O y + (x = 1-5, y = 1-15) was prepared using a combination of the ionic cyclotron resonance method and Knudsen effusion source. Dependence of concentration of different molybdenum oxide ions on the time of retention and their interaction with carbon monoxide was studied. It is shown that Mo x O y + ions with x>3 contain cyclic fragment Mo 3 O 9 in their structure. Oxygen binding energies within ionic clusters Mo x O y + were estimated [ru

  1. Ionization and fragmentation of water clusters by fast highly charged ions

    International Nuclear Information System (INIS)

    Adoui, L; Cassimi, A; Gervais, B; Grandin, J-P; Guillaume, L; Maisonny, R; Legendre, S; Tarisien, M; Lopez-Tarifa, P; Alcami, M; Martin, F; Politis, M-F; Penhoat, M-A Herve du; Vuilleumier, R; Gaigeot, M-P; Tavernelli, I

    2009-01-01

    We study the dissociative ionization of water clusters by impact of 12 MeV/u Ni 25+ ions. Cold target recoil ion momentum spectroscopy (COLTRIMS) is used to obtain information about stability, energetics and charge mobility of the ionized water clusters. An unusual stability of the H 9 O + 4 ion is observed, which could be the signature of the so-called Eigen structure in gas-phase water clusters. From the analysis of coincidences between charged fragments, we conclude that charge mobility is very high and is responsible for the formation of protonated water clusters, (H 2 O) n H + , that dominate the mass spectrum. These results are supported by Car-Parrinello molecular dynamics and time-dependent density functional theory simulations, which also reveal the mechanisms of such mobility.

  2. Self-Assembled Gold Nano-Ripple Formation by Gas Cluster Ion Beam Bombardment.

    Science.gov (United States)

    Tilakaratne, Buddhi P; Chen, Quark Y; Chu, Wei-Kan

    2017-09-08

    In this study, we used a 30 keV argon cluster ion beam bombardment to investigate the dynamic processes during nano-ripple formation on gold surfaces. Atomic force microscope analysis shows that the gold surface has maximum roughness at an incident angle of 60° from the surface normal; moreover, at this angle, and for an applied fluence of 3 × 10 16 clusters/cm², the aspect ratio of the nano-ripple pattern is in the range of ~50%. Rutherford backscattering spectrometry analysis reveals a formation of a surface gradient due to prolonged gas cluster ion bombardment, although the surface roughness remains consistent throughout the bombarded surface area. As a result, significant mass redistribution is triggered by gas cluster ion beam bombardment at room temperature. Where mass redistribution is responsible for nano-ripple formation, the surface erosion process refines the formed nano-ripple structures.

  3. New cultivar produced by heavy-ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kanaya, Takeshi; Miyazaki, Kiyoshi; Suzuki, Kenichi; Iwaki, Kazunari [Suntory Flowers Ltd., Higashiomi, Shiga (Japan); Ichida, Hiroyuki; Hayashi, Yoriko; Saito, Hiroyuki; Ryuto, Hiromichi; Fukunishi, Nobuhisa; Abe, Tomoko [RIKEN, Nishina Center, Wako, Saitama (Japan)

    2007-03-15

    The RIKEN accelerator research facility (RARF) is the one of the biggest facilities to accelerate heavy ions in all over the world since 1986. We started our trials in plant breeding since 1993. Soon we found that the ion beam is highly effective in the cause of mutagenesis of tobacco embryos during the fertilization without damage to other plant tissue. RIKEN and Suntory Flowers Ltd. have jointly developed some new ornamental varieties of Verbena and Petunia using ion-beam irradiation. We already put 5 new flower cultivars on the market in Japan, USA, Canada and EU since 2002. We report here a new variety of Torenia obtained by ion-beam irradiation. (author)

  4. Thin TaC layer produced by ion mixing

    DEFF Research Database (Denmark)

    Barna, Árpád; Kotis, László; Pécz, Béla

    2012-01-01

    in strongly asymmetric ion mixing; the carbon was readily transported to the Ta layer, while the reverse process was much weaker. Because of the asymmetrical transport the C/TaC interface remained sharp independently from the applied fluence. The carbon transported to the Ta layer formed Ta......Ion-beam mixing in C/Ta layered systems was investigated. C 8nm/Ta 12nm and C 20nm/Ta 19nm/C 20nm layer systems were irradiated by Ga+ ions of energy in the range of 2–30keV. In case of the 8nm and 20nm thick C cover layers applying 5–8keV and 20–30keV Ga+ ion energy, respectively resulted...

  5. New cultivar produced by heavy-ion beam irradiation

    International Nuclear Information System (INIS)

    Kanaya, Takeshi; Miyazaki, Kiyoshi; Suzuki, Kenichi; Iwaki, Kazunari; Ichida, Hiroyuki; Hayashi, Yoriko; Saito, Hiroyuki; Ryuto, Hiromichi; Fukunishi, Nobuhisa; Abe, Tomoko

    2007-01-01

    The RIKEN accelerator research facility (RARF) is the one of the biggest facilities to accelerate heavy ions in all over the world since 1986. We started our trials in plant breeding since 1993. Soon we found that the ion beam is highly effective in the cause of mutagenesis of tobacco embryos during the fertilization without damage to other plant tissue. RIKEN and Suntory Flowers Ltd. have jointly developed some new ornamental varieties of Verbena and Petunia using ion-beam irradiation. We already put 5 new flower cultivars on the market in Japan, USA, Canada and EU since 2002. We report here a new variety of Torenia obtained by ion-beam irradiation. (author)

  6. Structure and dynamics of ion clusters in linear octupole traps: Phase diagrams, chirality, and melting mechanisms

    International Nuclear Information System (INIS)

    Yurtsever, E.; Onal, E. D.; Calvo, F.

    2011-01-01

    The stable structures and melting dynamics of clusters of identical ions bound by linear octupole radiofrequency traps are theoretically investigated by global optimization methods and molecular dynamics simulations. By varying the cluster sizes in the range of 10-1000 ions and the extent of trap anisotropy by more than one order of magnitude, we find a broad variety of stable structures based on multiple rings at small sizes evolving into tubular geometries at large sizes. The binding energy of these clusters is well represented by two contributions arising from isotropic linear and octupolar traps. The structures generally exhibit strong size effects, and chiral arrangements spontaneously emerge in many crystals. Sufficiently large clusters form nested, coaxial tubes with different thermal stabilities. As in isotropic octupolar clusters, the inner tubes melt at temperatures that are lower than the overall melting point.

  7. Techniques to produce and accelerate radioactive ion beams

    CERN Document Server

    Penescu, Liviu Constantin; Lettry, Jacques; Cata-Danil, Gheorghe

    The production and acceleration of the Radioactive Ion Beams (RIB) continues the long line of nuclear investigations started in the XIXth century by Pierre and Marie Curie, Henri Becquerel and Ernest Rutherford. The contemporary applications of the RIBs span a wide range of physics fields: nuclear and atomic physics, solid-state physics, life sciences and material science. ISOLDE is a world-leading Isotope mass-Separation On-Line (ISOL) facility hosted at CERN in Geneva for more than 40 years, offering the largest variety of radioactive ion beams with, until now, more than 1000 isotopes of more than 72 elements (with Z ranging from 2 to 88), with half-lives down to milliseconds and intensities up to 1011 ions/s. The post acceleration of the full variety of beams allows reaching final energies between 0.8 and 3.0 MeV/u. This thesis describes the development of a new series of FEBIAD (“Forced Electron Beam Induced Arc Discharge”) ion sources at CERN-ISOLDE. The VADIS (“Versatile Arc Discharge Ion Source�...

  8. Minimization of Ion-Solvent Clusters in Gel Electrolytes Containing Graphene Oxide Quantum Dots for Lithium-Ion Batteries.

    Science.gov (United States)

    Chen, Yen-Ming; Hsu, Shih-Ting; Tseng, Yu-Hsien; Yeh, Te-Fu; Hou, Sheng-Shu; Jan, Jeng-Shiung; Lee, Yuh-Lang; Teng, Hsisheng

    2018-03-01

    This study uses graphene oxide quantum dots (GOQDs) to enhance the Li + -ion mobility of a gel polymer electrolyte (GPE) for lithium-ion batteries (LIBs). The GPE comprises a framework of poly(acrylonitrile-co-vinylacetate) blended with poly(methyl methacrylate) and a salt LiPF 6 solvated in carbonate solvents. The GOQDs, which function as acceptors, are small (3-11 nm) and well dispersed in the polymer framework. The GOQDs suppress the formation of ion-solvent clusters and immobilize PF6- anions, affording the GPE a high ionic conductivity and a high Li + -ion transference number (0.77). When assembled into Li|electrolyte|LiFePO 4 batteries, the GPEs containing GOQDs preserve the battery capacity at high rates (up to 20 C) and exhibit 100% capacity retention after 500 charge-discharge cycles. Smaller GOQDs are more effective in GPE performance enhancement because of the higher dispersion of QDs. The minimization of both the ion-solvent clusters and degree of Li + -ion solvation in the GPEs with GOQDs results in even plating and stripping of the Li-metal anode; therefore, Li dendrite formation is suppressed during battery operation. This study demonstrates a strategy of using small GOQDs with tunable properties to effectively modulate ion-solvent coordination in GPEs and thus improve the performance and lifespan of LIBs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. EPR study of N+-ion-induced free radical formation in antibiotic-producers

    International Nuclear Information System (INIS)

    Xie Liqing; Zhang Yinfen; Chen Ruyi; Gao Juncheng; Zhang Peiling; Ying Hengfeng.

    1995-01-01

    Under the room temperature, electron paramagnetic resonance (EPR) spectrometer was used to study free radical formation in antibiotic-producers in order to investigate antibiotic-producer mutagenic breeding, which were induced by N + ion implanting into antibiotic-producers (e.g., Streptomyces ribosidificus, Streptomyces kanamyceticus and the phage-resistant culture of Streptomyces kanamyceticus). The results show that a lot of free radicals can be induced by N + ion implanting into antibiotic-producers, and the yields of the free radicals increase with implanting dose. The death rate of antibiotic-producers rises due to the increase of N + -ion-induced free radical yields. (author)

  10. First multispacecraft ion measurements in and near the Earth’s magnetosphere with the identical Cluster ion spectrometry (CIS experiment

    Directory of Open Access Journals (Sweden)

    H. Rème

    2001-09-01

    Full Text Available On board the four Cluster spacecraft, the Cluster Ion Spectrometry (CIS experiment measures the full, three-dimensional ion distribution of the major magnetospheric ions (H+, He+, He++, and O+ from the thermal energies to about 40 keV/e. The experiment consists of two different instruments: a COmposition and DIstribution Function analyser (CIS1/CODIF, giving the mass per charge composition with medium (22.5° angular resolution, and a Hot Ion Analyser (CIS2/HIA, which does not offer mass resolution but has a better angular resolution (5.6° that is adequate for ion beam and solar wind measurements. Each analyser has two different sensitivities in order to increase the dynamic range. First tests of the instruments (commissioning activities were achieved from early September 2000 to mid January 2001, and the operation phase began on 1 February 2001. In this paper, first results of the CIS instruments are presented showing the high level performances and capabilities of the instruments. Good examples of data were obtained in the central plasma sheet, magnetopause crossings, magnetosheath, solar wind and cusp measurements. Observations in the auroral regions could also be obtained with the Cluster spacecraft at radial distances of 4–6 Earth radii. These results show the tremendous interest of multispacecraft measurements with identical instruments and open a new area in magnetospheric and solar wind-magnetosphere interaction physics.Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; magnetopheric configuration and dynamics; solar wind - magnetosphere interactions

  11. A dual cryogenic ion trap spectrometer for the formation and characterization of solvated ionic clusters

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, Brett M.; Voss, Jonathan M.; Garand, Etienne, E-mail: egarand@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706 (United States)

    2015-11-28

    A new experimental approach is presented in which two separate cryogenic ion traps are used to reproducibly form weakly bound solvent clusters around electrosprayed ions and messenger-tag them for single-photon infrared photodissociation spectroscopy. This approach thus enables the vibrational characterization of ionic clusters comprised of a solvent network around large and non-volatile ions. We demonstrate the capabilities of the instrument by clustering water, methanol, and acetone around a protonated glycylglycine peptide. For water, cluster sizes with greater than twenty solvent molecules around a single ion are readily formed. We further demonstrate that similar water clusters can be formed around ions having a shielded charge center or those that do not readily form hydrogen bonds. Finally, infrared photodissociation spectra of D{sub 2}-tagged GlyGlyH{sup +} ⋅ (H{sub 2}O){sub 1−4} are presented. They display well-resolved spectral features and comparisons with calculations reveal detailed information on the solvation structures of this prototypical peptide.

  12. Ionization and scintillation produced by relativistic Au, He and H ions in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Shibamura, E; Masuda, K; Crawford, H J; Engelage, J M; Doke, T; Hitachi, A; Kikuchi, J; Flores, I; Lindstrom, P J; Ogura, K

    1987-10-15

    We have measured ionization and scintillation produced by relativistic ions of Au, He and H in liquid argon. The sum of ionization signal and scintillation signal per unit energy deposition is the same for He and H ions, which is also the same as that for relativistic Ne, Fe and La ions previously measured. We have found that quenching occurs when liquid argon is irradiated by relativistic Au ions and that the sum per unit energy deposition for the Au ions is 70-76% of that for the other ions mentioned above.

  13. Cluster ion formation during sputtering processes: a complementary investigation by ToF-SIMS and plasma ion mass spectrometry

    International Nuclear Information System (INIS)

    Welzel, T; Ellmer, K; Mändl, S

    2014-01-01

    Plasma ion mass spectrometry using a plasma process monitor (PPM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) have been complementarily employed to investigate the sputtering and ion formation processes of Al-doped zinc oxide. By comparing the mass spectra, insights on ion formation and relative cross-sections have been obtained: positive ions as measured during magnetron sputtering by PPM are originating from the plasma while those in SIMS start at the surface leading to large differences in the mass spectra. In contrast, negative ions originating at the surface will be accelerated through the plasma sheath. They arrive at the PPM after traversing the plasma nearly collisionless as seen from the rather similar spectra. Hence, it is possible to combine the high mass resolution of ToF-SIMS to obtain insight for separating cluster ions, e.g. Zn x and ZnO y , and the energy resolution of PPM to find fragmentation patterns for negative ions. While the ion formation processes during both experiments can be assumed to be similar, differences may arise due to the lower volume probed by SIMS. In the latter case, there is a chance of small target inhomogeneities being able to be enhanced and lower surface temperatures leading to less outgassing and, thus, retention of volatile compounds. (paper)

  14. CHARACTERISTICS OF THE SECONDARY BUBBLE CLUSTER PRODUCED BY AN ELECTROHYDRAULIC SHOCK WAVE LITHOTRIPTER

    Science.gov (United States)

    Zhou, Yufeng; Qin, Jun; Zhong, Pei

    2013-01-01

    This study investigated the characteristics of the secondary bubble cluster produced by an electrohydraulic lithotripter using high-speed imaging and passive cavitation detection techniques. The results showed that (i) the discrepancy of the collapse time between near a flat rigid boundary and in a free field of the secondary bubble cluster was not as significant as that by the primary one; (ii) the secondary bubble clusters were small but in a high bubble density and nonuniform in distribution, and they did not expand and aggregate significantly near a rigid boundary; and (iii) the corresponding bubble collapse was weaker with few microjet formation and bubble rebound. By applying a strong suction flow near the electrode tip, the production of the secondary shock wave (SW) and induced bubble cluster could be disturbed significantly, but without influence on the primary ones. Consequently, stone fragmentation efficiency was reduced from 41.2 ± 7.1% to 32.2 ± 3.5% after 250 shocks (p <0.05). Altogether, these observations suggest that the secondary bubble cluster produced by an electrohydraulic lithotripter may contribute to its ability for effective stone fragmentation. PMID:22390990

  15. Unusual behavior in magnesium-copper cluster matter produced by helium droplet mediated deposition

    Energy Technology Data Exchange (ETDEWEB)

    Emery, S. B., E-mail: samuel.emery@navy.mil; Little, B. K. [University of Dayton Research Institute, 300 College Park, Dayton, Ohio 45469 (United States); Air Force Research Laboratory, Munitions Directorate, 2306 Perimeter Rd., Eglin AFB, Florida 32542 (United States); Xin, Y. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States); Ridge, C. J.; Lindsay, C. M. [Air Force Research Laboratory, Munitions Directorate, 2306 Perimeter Rd., Eglin AFB, Florida 32542 (United States); Buszek, R. J. [ERC Inc., Edwards AFB, California 93524 (United States); Boatz, J. A. [Air Force Research Laboratory, Aerospace System Directorate, Edwards AFB, California 93524 (United States); Boyle, J. M. [Naval Surface Warfare Center Indian Head Explosive Ordnance Technology Division, Indian Head, Maryland 20640 (United States)

    2015-02-28

    We demonstrate the ability to produce core-shell nanoclusters of materials that typically undergo intermetallic reactions using helium droplet mediated deposition. Composite structures of magnesium and copper were produced by sequential condensation of metal vapors inside the 0.4 K helium droplet baths and then gently deposited onto a substrate for analysis. Upon deposition, the individual clusters, with diameters ∼5 nm, form a cluster material which was subsequently characterized using scanning and transmission electron microscopies. Results of this analysis reveal the following about the deposited cluster material: it is in the un-alloyed chemical state, it maintains a stable core-shell 5 nm structure at sub-monolayer quantities, and it aggregates into unreacted structures of ∼75 nm during further deposition. Surprisingly, high angle annular dark field scanning transmission electron microscopy images revealed that the copper appears to displace the magnesium at the core of the composite cluster despite magnesium being the initially condensed species within the droplet. This phenomenon was studied further using preliminary density functional theory which revealed that copper atoms, when added sequentially to magnesium clusters, penetrate into the magnesium cores.

  16. Study of resonances produced in Heavy Ion Collisions

    Science.gov (United States)

    Quattrocchi, L.; Acosta, L.; Auditore, L.; Cardella, G.; Chbihi, A.; De Filippo, E.; Favela, F.; Gnoffo, B.; Lanzalone, G.; Martel, I.; Martorana, N. S.; Pagano, A.; Pagano, E. V.; Papa, M.; Pirrone, S.; Politi, G.; Porto, F.; Rizzo, F.; Russotto, P.; Trifirò, A.; Trimarchi, M.; Verde, G.; Veselsky, M.

    2018-05-01

    At Laboratori Nazionali del Sud of Catania an experiment has been carried out in order to investigate the correlations between particles produced in 12C+24Mg reaction at 35 AMeV incident energy. Two α correlation has been explored because provide information about temperature of 8Be nuclei produced in the reaction, while three α correaltion has been studied in order to evaluate the competition between sequential and direct decay mode of resonances produced in 12C quasi-projectiles.

  17. Detection of high mass cluster ions sputtered from Bi surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, A; Hewitt, R W; Slusser, G J; Baitinger, W E; Cooks, R G; Winograd, N [Purdue Univ., Lafayette, Ind. (USA). Dept. of Chemistry; Delgass, W N [Purdue Univ., Lafayette, Ind. (USA); Varon, A; Devant, G [Societe RIBER, 92 - Rueil-Malmaison (France)

    1976-12-01

    The technique of secondary ion mass spectrometry (SIMS) has been employed to detect Bi/sup 3 +/ ions and associated oxides Bi/sub 3/Osub(x)sup(+)(x=1 to 4) from a Bi foil. Using a 3 keV Ar/sup +/ ion primary beam of 5x10/sup -7/ A/cm/sup 2/, mass resolution to nearly 700 with the requisite sensitivity has been achieved. The Bi surface was also monitored by X-ray photoelectron spectroscopy (XPS or ESCA). The presence of a weak O 1s peak at 532.7 eV and a strong SIMS Bi/sup 3 +/ peak is interpreted to mean that the oxygen is weakly incorporated into the Bi lattice without disrupting metal-metal bonds.

  18. Transmitted ion energy loss distributions to detect cluster formation in silicon

    International Nuclear Information System (INIS)

    Selen, L.J.M.; Loon, A. van; IJzendoorn, L.J. van; Voigt, M.J.A. de

    2002-01-01

    The energy loss distribution of ions transmitted through a 5.7±0.2 μm thick Si crystal was measured and simulated with the Monte Carlo channeling simulation code FLUX. A general resemblance between the measured and simulated energy loss distributions was obtained after incorporation of an energy dependent energy loss in the simulation program. The energy loss calculations are used to investigate the feasibility to detect the presence of light element dopant clusters in a host crystal from the shape of the energy loss distribution, with transmission ion channeling. A curved crystal structure is used as a model for a region in the host crystal with clusters. The presence of the curvature does have a large influence on the transmitted energy distribution, which offers the possibility to determine the presence of dopant clusters in a host crystal with transmission ion channeling

  19. Ion induced electron emission statistics under Agm- cluster bombardment of Ag

    Science.gov (United States)

    Breuers, A.; Penning, R.; Wucher, A.

    2018-05-01

    The electron emission from a polycrystalline silver surface under bombardment with Agm- cluster ions (m = 1, 2, 3) is investigated in terms of ion induced kinetic excitation. The electron yield γ is determined directly by a current measurement method on the one hand and implicitly by the analysis of the electron emission statistics on the other hand. Successful measurements of the electron emission spectra ensure a deeper understanding of the ion induced kinetic electron emission process, with particular emphasis on the effect of the projectile cluster size to the yield as well as to emission statistics. The results allow a quantitative comparison to computer simulations performed for silver atoms and clusters impinging onto a silver surface.

  20. Ion turbulence and thermal transport in laser-produced plasmas

    International Nuclear Information System (INIS)

    Barr, H.C.; Boyd, T.J.M.

    1982-01-01

    In the interaction of high-intensity lasers with target plasmas the transport of thermal energy from the region in which the radiation is absorbed, to the cold dense plasma in the interior of the target, is an issue of central importance. The role of ion turbulence as a flux limiter is addressed with particular regard to recent experiments in which target plasmas were irradiated by 1.06 μm neodymium laser light at irradiances of 10 15 W cm - 2 and greater. Saturation levels of the ion-acoustic turbulence driven by a combination of a suprathermal electron current and a heat flux are calculated on the basis of perturbed orbit theory. The levels of turbulence are found to be markedly lower than those commonly estimated from simple trapping arguments and too low to explain the thermal flux inhibition observed in the experiments used as a basis for the model. (author)

  1. Cluster observations of trapped ions interacting with magnetosheath mirror modes

    Czech Academy of Sciences Publication Activity Database

    Souček, Jan; Escoubet, C. P.

    2011-01-01

    Roč. 29, - (2011), s. 1049-1060 ISSN 0992-7689 Institutional research plan: CEZ:AV0Z30420517 Keywords : mirror mode waves * trapped particles * magnetosheath ions Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.842, year: 2011 http://www.ann-geophys.net/29/1049/2011/angeo-29-1049-2011.pdf

  2. Vacancy defect and defect cluster energetics in ion-implanted ZnO

    Science.gov (United States)

    Dong, Yufeng; Tuomisto, F.; Svensson, B. G.; Kuznetsov, A. Yu.; Brillson, Leonard J.

    2010-02-01

    We have used depth-resolved cathodoluminescence, positron annihilation, and surface photovoltage spectroscopies to determine the energy levels of Zn vacancies and vacancy clusters in bulk ZnO crystals. Doppler broadening-measured transformation of Zn vacancies to vacancy clusters with annealing shifts defect energies significantly lower in the ZnO band gap. Zn and corresponding O vacancy-related depth distributions provide a consistent explanation of depth-dependent resistivity and carrier-concentration changes induced by ion implantation.

  3. Study of clusters using negative ion photodetachment spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yuexing [Univ. of California, Berkeley, CA (United States)

    1995-12-01

    The weak van der Waals interaction between an open-shell halogen atom and a closed-shell atom or molecule has been investigated using zero electron kinetic energy (ZEKE) spectroscopy. This technique is also applied to study the low-lying electronic states in GaAs and GaAs-. In addition, the spectroscopy and electron detachment dynamics of several small carbon cluster anions are studied using resonant multiphoton detachment spectroscopy.

  4. Study of clusters using negative ion photodetachment spectroscopy

    International Nuclear Information System (INIS)

    Zhao, Yuexing.

    1995-12-01

    The weak van der Waals interaction between an open-shell halogen atom and a closed-shell atom or molecule has been investigated using zero electron kinetic energy (ZEKE) spectroscopy. This technique is also applied to study the low-lying electronic states in GaAs and GaAs - . In addition, the spectroscopy and electron detachment dynamics of several small carbon cluster anions are studied using resonant multiphoton detachment spectroscopy

  5. Formation of aluminum films on silicon by ion beam deposition: a comparison with ionized cluster beam deposition

    International Nuclear Information System (INIS)

    Zuhr, R.A.; Haynes, T.E.; Galloway, M.D.; Tanaka, S.; Yamada, A.; Yamada, I.

    1991-01-01

    The direct ion beam deposition (IBD) technique has been used to study the formation of oriented aluminum films on single crystal silicon substrates. In the IBD process, thin film growth is accomplished by decelerating a magnetically analyzed ion beam to low energies (10-200 eV) for direct deposition onto the substrate under UHV conditions. The aluminum-on-silicon system is one which has been studied extensively by ionized cluster beam (ICB) deposition. This technique has produced intriguing results for aluminum, with oriented crystalline films being formed at room temperature in spite of the 25% mismatch in lattice constant between aluminum and silicon. In this work, we have studied the formation of such films by IBD, with emphasis on the effects of ion energy, substrate temperature, and surface cleanliness. Oriented films have been grown on Si(111) at temperatures from 40 to 300degC and with ion energies of 30-120 eV per ion. Completed films were analyzed by ion scattering, X-ray diffraction, scanning-electron microscopy, and optical microscopy. Results achieved for thin films grown by IBD are comparable to those for similar films grown by ICB deposition. (orig.)

  6. Molecular growth in clusters of polycyclic aromatic hydrocarbons induced by collisions with ions

    International Nuclear Information System (INIS)

    Delaunay, Rudy

    2016-01-01

    This thesis concerns the experimental study of the interaction between low energy ions (keV range) and neutral isolated molecules or clusters of polycyclic aromatic hydrocarbons (PAH) in the gas phase. The use of ionising radiations on these complex molecular systems of astrophysical interest allowed to highlight processes of statistical fragmentation, corresponding to the redistribution of the energy through the degrees of freedom of the target, and non-statistical fragmentation, linked to binary collisions of the ions on the nuclei of the target. A mechanism of intermolecular growth in clusters of PAH is observed. It is associated to the ultrafast (≤ ps) formation of fragments inside the clusters following binary collisions. The presence of a molecular environment around the fragments formed during the interaction may initiate a process of reactivity between the fragments and the molecules of the clusters. More precisely, the study focusses on the importance of the electronic stopping power SE and the nuclear stopping power SN of the projectile ion. It shows that the molecular growth is enhanced when SN is higher than SE. This can be explained by the fact that the deposit of energy is mainly due to the interaction with the nuclei of the target. The process of growth has been observed for all the molecules of PAH studied during this thesis and also for nitrogenated analogues of the molecule of anthracene. This demonstrates that molecular growth may be efficiently induced by collisions of low energy ions with clusters of PAH. (author) [fr

  7. Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Ahmet S., E-mail: asozcan@us.ibm.com [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Lavoie, Christian; Jordan-Sweet, Jean [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States); Alptekin, Emre; Zhu, Frank [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States); Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M. [TEL Epion Inc., 900 Middlesex Turnpike, Bldg. 6, Billerica, Massachusetts 01821 (United States)

    2016-04-21

    We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

  8. Investigation of energy thresholds of atomic and cluster sputtering of some elements under ion bombardment

    CERN Document Server

    Atabaev, B G; Lifanova, L F

    2002-01-01

    Threshold energies of sputtering of negative cluster ions from the Si(111) surface were measured at bombardment by Cs sup + , Rb sup + , and Na sup + ions with energy of 0.1-3.0 keV. These results are compared with the calculations of the similar thresholds by Bohdansky etc. formulas (3) for clusters Si sub n sup - and Cu sub n sup - with n=(1-5) and also for B, C, Al, Si, Fe, Cu atoms. Threshold energies of sputtering for the above elements were also estimated using the data from (5). Satisfactory agreement between the experimental and theoretical results was obtained. (author)

  9. Acceleration of cluster and molecular ions by TIARA 3 MV tandem accelerator

    CERN Document Server

    Saitoh, Y; Tajima, S

    2000-01-01

    We succeeded in accelerating molecular and cluster ions (B sub 2 sub - sub 4 , C sub 2 sub - sub 1 sub 0 , O sub 2 , Al sub 2 sub - sub 4 , Si sub 2 sub - sub 4 , Cu sub 2 sub - sub 3 , Au sub 2 sub - sub 3 , LiF, and AlO) to MeV energies with high-intensity beam currents by means of a 3 MV tandem accelerator in the TIARA facility. These cluster ions were generated by a cesium sputter-type negative ion source. We tested three types of carbon sputter cathodes in which graphite powder was compressed with different pressures. The pressure difference affected the generating ratio of clusters generated to single atom ions extracted from the source and it appeared that the high-density cathode was suitable. We also investigated the optimum gas pressure for charge exchange in the tandem high-voltage terminal. Clusters of larger size tend to require lower pressure than do smaller ones. In addition, we were able to obtain doubly charged AlO molecular ions. (authors)

  10. Electronic structure and dynamics of ordered clusters with ME or RE ions on oxide surface

    Energy Technology Data Exchange (ETDEWEB)

    Kulagin, N.A., E-mail: nkulagin@bestnet.kharkov.u [Kharkiv National University for Radio Electronics, Avenue Shakespeare 6-48, 61045 Kharkiv (Ukraine)

    2011-03-15

    Selected data of ab initio simulation of the electronic structure and spectral properties of either cluster with ions of iron, rare earth or actinium group elements have been presented here. Appearance of doped Cr{sup +4} ions in oxides, Cu{sup +2} in HTSC, Nd{sup +2} in solids has been discussed. Analysis of experimental data for plasma created ordered structures of crystallites with size of about 10{sup -9} m on surface of separate oxides are given, too. Change in the spectroscopic properties of clusters and nano-structures on surface of strontium titanate crystals discussed shortly using the X-ray line spectroscopy experimental results. - Research highlights: External influence and variation of technology induce changes in valence of nl ions in compounds. Wave function of cluster presented as anti-symmetrical set of ions wave functions. The main equation describes the self-consistent field depending on state of all electrons of cluster. Level scheme of Cr{sup 4+} ions in octo- and tetra-site corresponds to doped oxides spectra after treatment. Plasma treatment effects in appearance of systems of unit crystallites with size of about 10{sup -6}-10{sup -9} m.

  11. Electronic structure and dynamics of ordered clusters with ME or RE ions on oxide surface

    International Nuclear Information System (INIS)

    Kulagin, N.A.

    2011-01-01

    Selected data of ab initio simulation of the electronic structure and spectral properties of either cluster with ions of iron, rare earth or actinium group elements have been presented here. Appearance of doped Cr +4 ions in oxides, Cu +2 in HTSC, Nd +2 in solids has been discussed. Analysis of experimental data for plasma created ordered structures of crystallites with size of about 10 -9 m on surface of separate oxides are given, too. Change in the spectroscopic properties of clusters and nano-structures on surface of strontium titanate crystals discussed shortly using the X-ray line spectroscopy experimental results. - Research highlights: → External influence and variation of technology induce changes in valence of nl ions in compounds. → Wave function of cluster presented as anti-symmetrical set of ions wave functions. → The main equation describes the self-consistent field depending on state of all electrons of cluster. → Level scheme of Cr 4+ ions in octo- and tetra-site corresponds to doped oxides spectra after treatment. → Plasma treatment effects in appearance of systems of unit crystallites with size of about 10 -6 -10 -9 m.

  12. Electrolytic process to produce sodium hypochlorite using sodium ion conductive ceramic membranes

    Science.gov (United States)

    Balagopal, Shekar; Malhotra, Vinod; Pendleton, Justin; Reid, Kathy Jo

    2012-09-18

    An electrochemical process for the production of sodium hypochlorite is disclosed. The process may potentially be used to produce sodium hypochlorite from seawater or low purity un-softened or NaCl-based salt solutions. The process utilizes a sodium ion conductive ceramic membrane, such as membranes based on NASICON-type materials, in an electrolytic cell. In the process, water is reduced at a cathode to form hydroxyl ions and hydrogen gas. Chloride ions from a sodium chloride solution are oxidized in the anolyte compartment to produce chlorine gas which reacts with water to produce hypochlorous and hydrochloric acid. Sodium ions are transported from the anolyte compartment to the catholyte compartment across the sodium ion conductive ceramic membrane. Sodium hydroxide is transported from the catholyte compartment to the anolyte compartment to produce sodium hypochlorite within the anolyte compartment.

  13. Photodissociation spectroscopy and dynamics of free radicals, clusters, and ions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyeon [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    The photodissociation spectroscopy and dynamics of free radicals and ions is studied to characterize the dissociative electronic states in these species. To accomplish this, a special method of radical production, based on the photodetachment of the corresponding negative ion, has been combined with the technique of fast beam photofragment translational spectroscopy. The photofragment yield as a function of photon energy is obtained, mapping out the dissociative and predissociative electronic states. Branching ratios to various product channels, the translational energy distributions of the fragments, and bond dissociation energies are then determined at selected photon energies. The detailed picture of photodissociation dynamics is provided with the aid of ab initio calculations and a statistical model to interpret the observed data. Important reaction intermediates in combustion reactions have been studied: CCO, C2H5O, and linear Cn (n = 4--6).

  14. Mass-spectrometric study of ion clustering in alkali-metal hydroxide vapor: cluster-ion energy and structural characteristics

    International Nuclear Information System (INIS)

    Kudin, L.S.; Butman, M.F.; Krasnov, K.S.

    1986-01-01

    Various positive and negative ions have been recorded in the equilibrium vapors from alkali-metal hydroxides: M/sup +/-/, OH - , O - , MO - , MOH - , and X/sup +/-/ (MOH)/sub n/, where X = M/sup +/-/, OH - , n = 1-6. The equilibrium constants have been measured for X/sup +/-/(MOH)/sub n/ = x/sup +/-/ + nMOH(k), n = 1-3, and the enthalpies of reaction have been determined, from which the enthalpies of formation and dissociation energies of X/sup +/-/ (MOH)/sub n/ have been calculated. The relative stabilities of the ions in the series from Na to Cs are examined

  15. Cluster approach to intranuclear cascade for relativistic heavy ion colisions

    International Nuclear Information System (INIS)

    Kodama, T.; Duarte, S.B.; Chung, K.C.; Nazareth, R.A.M.S.

    1982-01-01

    A new approach to the intranuclear cascade model for relativistic heavy ion reaction is presented. The effect of nucleon conventration on the collision process is explicitly included. It is found that the contributions from the non-binary processes are far from being negligible. Such processes are shown to broaden the angular distribution of inclusive proton spectra for 20 Ne + 238 U head-on collisions. (Author) [pt

  16. Applications of laser produced ion beams to nuclear analysis of materials

    International Nuclear Information System (INIS)

    Mima, K.; Azuma, H.; Fujita, K.; Yamazaki, A.; Okuda, C.; Ukyo, Y.; Kato, Y.; Arrabal, R. Gonzalez; Soldo, F.; Perlado, J. M.; Nishimura, H.; Nakai, S.

    2012-01-01

    Laser produced ion beams have unique characteristics which are ultra-short pulse, very low emittance, and variety of nuclear species. These characteristics could be used for analyzing various materials like low Z ion doped heavy metals or ceramics. Energies of laser produced ion beam extend from 0.1MeV to 100MeV. Therefore, various nuclear processes can be induced in the interactions of ion beams with samples. The ion beam driven nuclear analysis has been developed for many years by using various electrostatic accelerators. To explore the applicability of laser ion beam to the analysis of the Li ion battery, a proton beam with the diameter of ∼ 1.0 μm at Takasaki Ion Acceleration for Advanced Radiation Application (TIARA), JAEA was used. For the analysis, the PIGE (Particle-Induced Gamma Ray Emission) is used. The proton beam scans over Li battery electrode samples to diagnose Li density in the LiNi 0.85 Co 0.15 O 2 anode. As the results, PIGE images for Li area density distributions are obtained with the spatial resolution of better than 1.5μm FWHM. By the Li PIGE images, the depth dependence of de-intercalation levels of Li in the anode is obtained. By the POP experiments at TIARA, it is clarified that laser produced ion beam is appropriate for the Li ion battery analysis. 41.85.Lc, 41.75.Jv, 42.62.cf.

  17. Thermodynamic modeling of the formation and stability of small tin clusters and their ions

    International Nuclear Information System (INIS)

    Kodlaa, A.; Suliman, A.

    2005-01-01

    Based on the results of previous quantum-chemical study of electronic structure properties for neutral and single positively and negatively charged thin clusters in the size range of N 2-17 atoms, and on the thermodynamic laws, we have studied the thermodynamic properties of tin clusters and their ions. The characteristic amounts (cohesive enthalpy, formation enthalpy, fragmentation enthalpy, entropy and free enthalpy) for the formation and stability of these clusters at different temperatures were calculated. From the results, which are presented and discussed in this work, one can observe the following: The tin clusters Sn N (N=2-17) and their cations Sn + N and anions Sn - N are formed in the gas phase, and this agrees with experimental results. The clusters Sn 3 and Sn 1 0 are the most stable clusters of all. Here we also, find a correspondence with the results of the experimental studies. Our results go beyond that since we have found Sn 1 5 is also specially stable. By this thermodynamic study we could evaluate approximately the formation and stability of small neutral, single positively and negatively charged tin clusters. It has also allowed us to study the effects of the temperature on the formation and stability of these clusters. The importance of such study is not only what mentioned above, but it is also the first thermodynamic study for modeling the formation and stability of small tin clusters. (author)

  18. Mass spectrometric analysis of small negative ions (e/m < 100) produced by Trichel pulse negative corona discharge fed by ozonised air

    OpenAIRE

    Skalny, J.D.; Horvath, G.; Mason, N.

    2007-01-01

    Mass spectrometric analysis of small negative ions (e/m < 100) produced by DC negative corona discharge in ozonised wet air both in flow and flow-stopped regimes was conducted at pressure of 30 kPa. The point-to-plain electrode system has been used. The yield of individual ions is strongly affected by trace concentrations of ozone in both regimes. Ozone concentration greater than 25 ppm is sufficient to completely suppress the appearance of O2- and a NO2- ion as well as theirs clusters in the...

  19. Study of multicharged ions in the laser-produced plasmas

    International Nuclear Information System (INIS)

    Jaegle, P.; Carillon, A.; Jamelot, G.; Wehenkel, C.; Sureau, A.; Guennou, H.

    1980-01-01

    With respect to hot plasmas, laser induced plasmas have an especially high density, with a steep partial gradient and a fast temporal variation of temperature and density. The study of multicharged ion radiation, wich is necessary to perform diagnostics of plasma parameters, opens a new field for atomic physics investigations, including identification of peculiar lines, which are not observed in other conditions, large changes in line profiles due to radiative transfer and to both shift and broadening by Stark effect. Departure from population equilibrium takes place in these plasmas, going possibly so far as population inversion between ionic levels in an energy range covering EUV and soft X-rays. Experimental and theoretical study of these phenomena are in progress and needs to find solutions for complicated problems. Here, recent works performed with the laser of the GRECO 'Interaction Laser-Matiere' are briefly presented [fr

  20. Protective and decorative coatings produced by ion-plasma deposition

    International Nuclear Information System (INIS)

    Radjabov, T.D.; Kamardin, A.I.; Pulatov, S.U.

    1996-01-01

    Vacuum device is worked out for the vacuum low temperature deposition of protective and decorative films and studied technical regimes of obtaining such films to target from the metal,plastics, ceramic and glass with thickness up to 10 mkm and square 1 m 2 /cycle. Vacuum device provide possibility to create films by means of magnetron with pressure 100-10 1 Pa to different targets and to conduct preliminary treatment of them by argon ion beam with 3-4 keV energy for the cleaning of surface. Protective films of Chrome, Titanium, Nitride of Titanium and stainless steel have shown high adhesion properties up to 300-400 kgs/sm and ensure stable protection of surface from air and chemical corrosion. Obtained films has good decorative and colour characteristics. (author). 2 figs

  1. Improved mass resolution and mass accuracy in TOF-SIMS spectra and images using argon gas cluster ion beams.

    Science.gov (United States)

    Shon, Hyun Kyong; Yoon, Sohee; Moon, Jeong Hee; Lee, Tae Geol

    2016-06-09

    The popularity of argon gas cluster ion beams (Ar-GCIB) as primary ion beams in time-of-flight secondary ion mass spectrometry (TOF-SIMS) has increased because the molecular ions of large organic- and biomolecules can be detected with less damage to the sample surfaces. However, Ar-GCIB is limited by poor mass resolution as well as poor mass accuracy. The inferior quality of the mass resolution in a TOF-SIMS spectrum obtained by using Ar-GCIB compared to the one obtained by a bismuth liquid metal cluster ion beam and others makes it difficult to identify unknown peaks because of the mass interference from the neighboring peaks. However, in this study, the authors demonstrate improved mass resolution in TOF-SIMS using Ar-GCIB through the delayed extraction of secondary ions, a method typically used in TOF mass spectrometry to increase mass resolution. As for poor mass accuracy, although mass calibration using internal peaks with low mass such as hydrogen and carbon is a common approach in TOF-SIMS, it is unsuited to the present study because of the disappearance of the low-mass peaks in the delayed extraction mode. To resolve this issue, external mass calibration, another regularly used method in TOF-MS, was adapted to enhance mass accuracy in the spectrum and image generated by TOF-SIMS using Ar-GCIB in the delayed extraction mode. By producing spectra analyses of a peptide mixture and bovine serum albumin protein digested with trypsin, along with image analyses of rat brain samples, the authors demonstrate for the first time the enhancement of mass resolution and mass accuracy for the purpose of analyzing large biomolecules in TOF-SIMS using Ar-GCIB through the use of delayed extraction and external mass calibration.

  2. Model of large volumetric capacitance in graphene supercapacitors based on ion clustering

    Science.gov (United States)

    Skinner, Brian; Fogler, M. M.; Shklovskii, B. I.

    2011-12-01

    Electric double-layer supercapacitors (SCs) are promising devices for high-power energy storage based on the reversible absorption of ions into porous conducting electrodes. Graphene is a particularly good candidate for the electrode material in SCs due to its high conductivity and large surface area. In this paper, we consider SC electrodes made from a stack of graphene sheets with randomly inserted spacer molecules. We show that the large volumetric capacitances C≳100F/cm3 observed experimentally can be understood as a result of collective intercalation of ions into the graphene stack and the accompanying nonlinear screening by graphene electrons that renormalizes the charge of the ion clusters.

  3. A model of large volumetric capacitance in graphene supercapacitors based on ion clustering

    Science.gov (United States)

    Skinner, Brian; Fogler, Michael; Shklovskii, Boris

    2012-02-01

    Electric double layer supercapacitors are promising devices for high-power energy storage based on the reversible absorption of ions into porous, conducting electrodes. Graphene is a particularly good candidate for the electrode material in supercapacitors due to its high conductivity and large surface area. In this paper we consider supercapacitor electrodes made from a stack of graphene sheets with randomly-inserted ``spacer" molecules. We show that the large volumetric capacitances C > 100 F/cm^3 observed experimentally can be understood as a result of collective intercalation of ions into the graphene stack and the accompanying nonlinear screening by graphene electrons that renormalizes the charge of the ion clusters.

  4. Site-specific fragmentation of polystyrene molecule using size-selected Ar gas cluster ion beam

    International Nuclear Information System (INIS)

    Moritani, Kousuke; Mukai, Gen; Hashinokuchi, Michihiro; Mochiji, Kozo

    2009-01-01

    The secondary ion mass spectrum (SIMS) of a polystyrene thin film was investigated using a size-selected Ar gas cluster ion beam (GCIB). The fragmentation in the SIM spectrum varied by kinetic energy per atom (E atom ); the E atom dependence of the secondary ion intensity of the fragment species of polystyrene can be essentially classified into three types based on the relationship between E atom and the dissociation energy of a specific bonding site in the molecule. These results indicate that adjusting E atom of size-selected GCIB may realize site-specific bond breaking within a molecule. (author)

  5. On the mechanism of water cluster-ion formation in carbon dioxide

    International Nuclear Information System (INIS)

    Warneck, P.; Rakshit, A.B.

    1981-01-01

    A drift chamber mass spectrometer has been used to study the formation of water cluster-ions in carbon dioxide containing traces of water vapour. The dominant reaction sequences were identified up to the fourth generation of daughter ions starting with CO 2 + . The subsequent reaction mechanism remains uncertain and several possibilities are discussed. The final ions are H 3 O + H 2 O and H 3 O + (H 2 O) 2 . The significance of the reaction schemes to the radiation chemistry of carbon dioxide is pointed out. (orig.)

  6. Effect of electrode for producing the highly charged heavy ions from RIKEN 18 GHz electron cyclotron resonance ion source

    International Nuclear Information System (INIS)

    Kurita, Tetsuro; Nakagawa, Takahide; Kidera, Masanori

    1999-01-01

    We successfully produced the intense beam of highly charged Kr ions using an electrode. Under the pulsed mode operation, we found that the depth of the plasma potential dip strongly depends on the duration of the microwave and takes about 40 ms to reach the equilibrium state. Taking these results into account, we compared the beam intensities of highly charged Kr ions with and without the use of an electrode under the pulsed mode operation. We observed that the density of highly charged Kr ions and ion confinement time increase with increasing mirror magnetic field strength. The plasma potential dip becomes shallower with insertion of the electrode. Consequently, when we increase the mirror magnetic field strength and insert the electrode into the plasma, the beam intensities of highly charged ions increase. (author)

  7. Surface Collisions of Small Cluster Ions at Incident Energies 10-102 eV

    Czech Academy of Sciences Publication Activity Database

    Herman, Zdeněk

    2004-01-01

    Roč. 233, - (2004), s. 361-371 ISSN 1387-3806 R&D Projects: GA MŠk ME 561 Grant - others:XE(CZ) EURATOM-IPP.CR Institutional research plan: CEZ:AV0Z4040901 Keywords : surface collisions * cluster ions * unimolecular dissociation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.235, year: 2004

  8. Physical principles of the surface-plasma method of producing beams of negative ions

    International Nuclear Information System (INIS)

    Bel'chenko, Yu.I.; Dimov, G.I.; Dudnikov, V.G.

    A study is made of the processes used to produce intensive beams of negative ions from surface-plasma sources (SPS). The concepts now being formulated concerning the formation of negative ions upon interaction of bombarding particles with the surface of a solid are analyzed. The peculiarities of the realization of optimal conditions for the production of beams of negative ions in SPS of various designs are discussed

  9. Fusion reaction spectra produced by anisotropic fast ions in the PLT tokamak

    International Nuclear Information System (INIS)

    Heidbrink, W.W.

    1984-02-01

    For beam-target fusion reactions, collimated measurements of the energy spectrum of one of the reaction products can provide information on the degree of anisotropy of the reacting beam ions. Measurements of the spectrum of 15 MeV protons produced by reactions between energetic 3 He ions and relatively cold deuterons during fast wave minority heating in the PLT tokamak indicate that the velocity distribution of fast 3 He ions is peaked perpendicular to the tokamak magnetic field

  10. Decay of hot nuclei produced by relativistic light ions

    International Nuclear Information System (INIS)

    Karnaukhov, V.A.; Avdeev, S.P.; Kuznetsov, V.D.

    1995-01-01

    In collisions of light relativistic projectiles (p, 4 He) with heavy nuclei (Au) very excited target spectators are created, which decay via multiple emission of intermediate mass fragments. It was found that the mean IMF multiplicities are equal (within 15%) to 2.0, 2.6 and 3.0 at proton energies 2.16, 3.6 and 8.1 GeV respectively. These values are comparable with those obtained with heavy ions in the same beam energy range. This is considered to indicate that this observable is not sensitive to the collision dynamics and is determined by the phase space factor. IMF energy spectra are described by the statistical model of multifragmentation neglecting dynamics of the expansion stage before the break up. The expansion velocity is estimated to be ≤ 0.02 c. The mean lifetime of a fragmentating system is found to be ≤ 75 fm/c from IMF-IMF-angular correlations for 4 He (14.6 GeV) +Au collisions. The results support a scenario of true 'thermal' multifragmentation. 26 refs., 10 figs., 1 tab

  11. Reflex tetrode for producing an efficient unidirectional ion beam

    International Nuclear Information System (INIS)

    Golden, J.; Kapetanakos, C.A.; Mahaffey, R.A.; Pasour, J.A.

    1980-01-01

    A reflex tetrode device for efficiently generating intense, pulsed unidirectional ion beams is disclosed. The device includes two thin, semitransparent anodes spaced from a real cathode which is maintained at ground potential. The first anode is spaced from and faces the real cathode. The second anode is spaced a short distance from the first anode and a virtual cathode is formed beyond the second anode when a sufficiently high electron current flows from the real cathode and through the anodes. The anodes are ring-like or disc-like structures secured to the edges of a support member with their planes perpendicular to the axis of the device between the real and virtual cathodes. The anode structure (i.e., the support member together with the two anodes) is connected to a pulsed high-voltage generator which is operated in positive polarity. Consequently, both anodes are at the same positive potential. The first anode, because of its material, does not readily form an ionic plasma when electrons pass through it, but the second anode does

  12. Electron-ion collision rates in atomic clusters irradiated by femtosecond laser pulses

    International Nuclear Information System (INIS)

    Moll, M; Hilse, P; Schlanges, M; Bornath, Th; Krainov, V P

    2010-01-01

    In atomic clusters irradiated by femtosecond laser pulses, plasmas with high density and high temperature are created. The heating is mainly caused by inverse bremsstrahlung, i.e. determined by electron-ion collisions. In the description of the scattering of electrons on noble gas ions in such plasmas, it is important to account for the inner structure of the ions and the screening by the surrounding plasma medium which can be accomplished by using suitable model potentials. In the wide parameter range met in experiments, the Born approximation is not applicable. Instead, the electron-ion collision frequency is calculated on the basis of classical momentum transport cross sections. Results are presented for xenon, krypton and argon ions in different charge states. A comparison of these results to those for the scattering on Coulomb particles with the same charge shows an enhancement of the collision frequency. The Born approximation, however, leads to an overestimation.

  13. Determination of interstellar pickup ion distributions in the solar wind with SOHO and Cluster

    Directory of Open Access Journals (Sweden)

    E. Möbius

    1996-05-01

    Full Text Available Over the last 10 years, the experimental basis for the study of the local interstellar medium has been substantially enhanced by the direct detection of interstellar pickup ions and of interstellar neutral helium within the heliosphere. Pickup ions can be studied for a wide range of interstellar species. However, currently the accuracy of the method to determine the parameters of the interstellar medium, namely neutral density, temperature and relative velocity, is hampered by two problems: (1 In most cases the crucial ionization rates are not available from simultaneous measurements and (2 the transport of the pickup ions in the interplanetary medium substantially modifies the measured spatial distribution of the ions. In this study we will discuss how the enhanced capabilities of the instrumentation on SOHO and Cluster in combination with ongoing efforts to model the pickup ion distributions will lead to a significant improvement over the coming years.

  14. Relaxation effects in ionic mobility and cluster formation: negative ions in SF6 at high pressures

    International Nuclear Information System (INIS)

    Juarez, A M; De Urquijo, J; Hinojosa, G; Hernandez-Avila, J L; Basurto, E

    2010-01-01

    The relaxation effects of the ionic mobility and the formation of negative-ion clusters in SF 6 are studied in this work. For this purpose, we have measured the mobility of negative ions in SF 6 over the pressure range 100-800 Torr at a fixed value of density-normalized electric field, E/N, of 20 Td (1 Townsend = 10 -17 V cm 2 ). The data obtained show a clear dependence of the negative-ion drift velocity on drift distance. It is observed that the drift velocity (mobility) reaches a steady-state value only for drift distances above 2 cm, over the studied pressure range. In addition to this, we have observed that the ionic mobility depends strongly on the gas pressure. An explanation of this dependence of the ionic mobility on gas pressure is given in terms of a negative-ion clustering formation process. It was found that the assumption of a linear dependence of the cluster ion mass on pressure provides a satisfactory explanation for the observed mobilities.

  15. New statistical function for the angular distribution of evaporation residues produced by heavy ions

    International Nuclear Information System (INIS)

    Rigol, J.

    1994-01-01

    A new statistical function has been found for modelling the angular distribution of evaporation residues produced by heavy ions. Experimental results are compared with the calculated ones. 11 refs.; 4 figs. (author)

  16. From molecular clusters to nanoparticles: second-generation ion-mediated nucleation model

    Directory of Open Access Journals (Sweden)

    F. Yu

    2006-01-01

    Full Text Available Ions, which are generated in the atmosphere by galactic cosmic rays and other ionization sources, may play an important role in the formation of atmospheric aerosols. In the paper, a new second-generation ion-mediated nucleation (IMN model is presented. The new model explicitly treats the evaporation of neutral and charged clusters and it describes the evolution of the size spectra and composition of both charged and neutral clusters/particles ranging from small clusters of few molecules to large particles of several micrometers in diameter. Schemes used to calculate the evaporation coefficients for small neutral and charged clusters are consistent with the experimental data within the uncertainty range. The present IMN model, which is size-, composition-, and type-resolved, is a powerful tool for investigating the dominant mechanisms and key parameters controlling the formation and subsequent growth of nanoparticles in the atmosphere. This model can be used to analyze simultaneous measurements of the ion-mobility spectra and particle size distributions, which became available only recently. General features of the spectra for ions smaller than the critical size, size-dependent fractions of charged nanoparticles, and asymmetrical charging of freshly nucleated particles predicted by the new IMN model are consistent with recent measurements. Results obtained using the second generation IMN model, in which the most recent thermodynamic data for neutral and charged H2SO4-H2O clusters were used, suggest that ion-mediated nucleation of H2SO4-H2O can lead to a significant production of new particles in the lower atmosphere (including the boundary layer under favorable conditions. It has been shown that freshly nucleated particles of few nanometers in size can grow by the condensation of low volatile organic compounds to the size of cloud condensation nuclei. In such cases, the chemical composition of nucleated particles larger than ~10 nm is dominated

  17. Ion clustering in aqueous salt solutions near the liquid/vapor interface

    Directory of Open Access Journals (Sweden)

    J.D. Smith

    2016-03-01

    Full Text Available Molecular dynamics simulations of aqueous NaCl, KCl, NaI, and KI solutions are used to study the effects of salts on the properties of the liquid/vapor interface. The simulations use the models which include both charge transfer and polarization effects. Pairing and the formation of larger ion clusters occurs both in the bulk and surface region, with a decreased tendency to form larger clusters near the interface. An analysis of the roughness of the surface reveals that the chloride salts, which have less tendency to be near the surface, have a roughness that is less than pure water, while the iodide salts, which have a greater surface affinity, have a larger roughness. This suggests that ions away from the surface and ions near the surface affect the interface in opposite ways.

  18. Ion-streaming induced order transition in three-dimensional dust clusters

    International Nuclear Information System (INIS)

    Ludwig, Patrick; Kählert, Hanno; Bonitz, Michael

    2012-01-01

    Dust dynamics simulations utilizing a dynamical screening approach are performed to study the effect of ion-streaming on the self-organized structures in a three-dimensional spherically confined complex (dusty) plasma. Varying the Mach number M, the ratio of ion drift velocity to the sound velocity, the simulations reproduce the experimentally observed cluster configurations in the two limiting cases: at M = 0 strongly correlated crystalline structures consisting of nested spherical shells (Yukawa balls) and, for M ⩾ 1, flow-aligned dust chains, respectively. In addition, our simulations reveal a discontinuous transition between these two limits. It is found that already a moderate ion drift velocity (M ≈ 0.1 for the plasma conditions considered here) destabilizes the highly ordered Yukawa balls and initiates an abrupt melting transition. The critical value of M is found to be independent of the cluster size. (paper)

  19. Slow, target associated particles produced in ultrarelativistic heavy-ion interactions

    Energy Technology Data Exchange (ETDEWEB)

    Adamovich, M I; Aggarwal, M M; Alexandrov, Y A; Andreeva, N P; Anson, Z V; Arora, R; Avetyan, F A; Badyal, S K; Basova, E; Bhalla, K B; Bhasin, A; Bhatia, V S; Bogdanov, V G; Bubnov, V I; Burnett, T H; Cai, X; Chasnikov, I Y; Chernova, L P; Chernyavsky, M M; Dressel, B; Eligbaeva, G Z; Eremenko, L E; Friedlander, E M; Gaitinov, A S; Ganssauge, E R; Garpman, S; Gerassimov, S G; Grote, J; Gulamov, K G; Gupta, S K; Gupta, V; Heckman, H H; Huang, H; Jakobsson, B; Judek, B; Kachroo, S; Kadyrov, F G; Kalyachkina, G S; Kanygina, E K; Karabova, M; Kaul, G L; Kaur, M; Kharlamov, S P; Koss, Y; Krasnov,; Kumar,; Lal, P; Larionova,; Lepetan,; Lindstrom,; Liu,; Lokanathan, S; Lord, J; Lukicheva, N S; Luo, S B; Mangotra, L K; Marutyan,; Maslennikova, N V; Mittra, I S; Mookerjee, S; Mueller, C; Nasrulaeva, H; Nasyrov, S H; Navotny, V S; Orlova, G I; Otterlund, I; Palsania, H S; Peresadko, N G; Petrov, N V; Plyushchev, V A; Qian, W Y; Raniwala,; EMU01 Collaboration

    1991-06-20

    The slow, target associated particles produced in ultrarelativistic heavy-ion interactions are a quantitative probe of the cascading processes in the spectator parts of the target nucleus. These processes are directly influenced by the proper timescale for the formation of hadronic matter. In this letter we show experimental data on singly and multiply charged particles, with velocities smaller than 0.7c, produced in ultrarelativistic heavy-ion interactions in nuclear emulsion. (orig.).

  20. Cluster Implantation and Deposition Apparatus

    DEFF Research Database (Denmark)

    Hanif, Muhammad; Popok, Vladimir

    2015-01-01

    In the current report, a design and capabilities of a cluster implantation and deposition apparatus (CIDA) involving two different cluster sources are described. The clusters produced from gas precursors (Ar, N etc.) by PuCluS-2 can be used to study cluster ion implantation in order to develop...

  1. Experimental study of the dissociation of 100-600 KeV hydrogen cluster ions in an argon gas target

    International Nuclear Information System (INIS)

    Chevallier, M.; Clouvas, A.; Frischkorn, H.J.; Gaillard, M.J.; Poizat, J.C.; Remillieux, J.

    1985-09-01

    We have studied the break-up of accelerated hydrogen cluster ions passing through an argon gas target. The absolute dissociation cross section has been measured for a wide variety of H n + (odd masses only) cluster ions, with n between 5 and 23 and with projectile velocities ranging from 1.5 to 5 x 10 8 cm/s. We discuss the dissociation processes and the dependence of their cross-sections upon the cluster mass and velocity

  2. Molecular dynamic simulation of interaction of low-energy Ar and Xe ions with copper clusters at graphite surface

    International Nuclear Information System (INIS)

    Kornich, G.V.; Lozovskaya, L.I.; Betts, G.; Zaporozhchenko, V.I.; Faupel, F.

    2005-01-01

    One conducted molecular and dynamic simulation of sputtering of isolated clusters consisting of 13, 27 and 195 Cu atoms from the (0001) graphite surface by 200 eV energy Ar and Xe ions. It is shown that the factors of reflection of Ar and Xe ions from copper clusters differ from one another insignificantly, though the energy of the reflected Xe ions is essentially lower than that of Ar ions. The values of the factor of cluster sputtering by Xe ions are higher in contrast to sputtering by Ar ions. One identified two mechanisms of cluster sputtering resulting in the maximum of sputtering intensity at the polar angles near the normal one, and in periodicity of maximums within the azimuth distributions of sputtering intensity with 60 deg period [ru

  3. Smart darting diffusion Monte Carlo: Applications to lithium ion-Stockmayer clusters

    International Nuclear Information System (INIS)

    Christensen, H. M.; Jake, L. C.; Curotto, E.

    2016-01-01

    In a recent investigation [K. Roberts et al., J. Chem. Phys. 136, 074104 (2012)], we have shown that, for a sufficiently complex potential, the Diffusion Monte Carlo (DMC) random walk can become quasiergodic, and we have introduced smart darting-like moves to improve the sampling. In this article, we systematically characterize the bias that smart darting moves introduce in the estimate of the ground state energy of a bosonic system. We then test a simple approach to eliminate completely such bias from the results. The approach is applied for the determination of the ground state of lithium ion-n–dipoles clusters in the n = 8–20 range. For these, the smart darting diffusion Monte Carlo simulations find the same ground state energy and mixed-distribution as the traditional approach for n < 14. In larger systems we find that while the ground state energies agree quantitatively with or without smart darting moves, the mixed-distributions can be significantly different. Some evidence is offered to conclude that introducing smart darting-like moves in traditional DMC simulations may produce a more reliable ground state mixed-distribution.

  4. Smart darting diffusion Monte Carlo: Applications to lithium ion-Stockmayer clusters

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, H. M.; Jake, L. C.; Curotto, E., E-mail: curotto@arcadia.edu [Department of Chemistry and Physics, Arcadia University, Glenside, Pennsylvania 19038-3295 (United States)

    2016-05-07

    In a recent investigation [K. Roberts et al., J. Chem. Phys. 136, 074104 (2012)], we have shown that, for a sufficiently complex potential, the Diffusion Monte Carlo (DMC) random walk can become quasiergodic, and we have introduced smart darting-like moves to improve the sampling. In this article, we systematically characterize the bias that smart darting moves introduce in the estimate of the ground state energy of a bosonic system. We then test a simple approach to eliminate completely such bias from the results. The approach is applied for the determination of the ground state of lithium ion-n–dipoles clusters in the n = 8–20 range. For these, the smart darting diffusion Monte Carlo simulations find the same ground state energy and mixed-distribution as the traditional approach for n < 14. In larger systems we find that while the ground state energies agree quantitatively with or without smart darting moves, the mixed-distributions can be significantly different. Some evidence is offered to conclude that introducing smart darting-like moves in traditional DMC simulations may produce a more reliable ground state mixed-distribution.

  5. Observations on small anionic clusters in an electrostatic ion beam trap

    International Nuclear Information System (INIS)

    Eritt, Markus

    2008-01-01

    The term atomic cluster relates to compounds of at least two or three atoms. Thereby the physical properties are size dependent and the property transitions between single atoms and bulk material are not always smooth. Ion traps allow it to observe internal cluster properties independent from the influence of external forces. In this work the electron induced decay of singly negatively charged atomic clusters was observed. The dissociation cross section of the clusters is dominated by detachment of the only weakly bound outer electrons. For simple atoms at low electron energies a simple scaling law can be obtained that includes only the binding energies of the valence electrons. Nevertheless for larger sizes theoretical calculations predict so called ''giant resonances'' as dominant decay process in metal clusters. Due to mass limitations in storage rings exist so far only cross section measurements for simple anions and small negative molecules. In this work the electron detachment cross sections of small negatively charged carbon (C n - n=2-12), aluminium (Al n - n=2-7) and silver clusters (Ag n - n=1-11) were measured in an electrostatic ion beam trap. The classical scaling law, including only the binding energies of the valence electrons, turned out to be not sufficient, especially for larger clusters. In order to improve the correlation between measured and predicted values it was proposed to involve the influence of the cluster volume and the specific polarisability induced by long range coulomb interaction. For silver clusters the best agreement was obtained using a combination of the projected area reduced by the polarisability. The existence of ''giant resonances'' could not be confirmed. According to theory for clusters with a broad internal energy distribution, a power-law decay close to 1/time is expected. For some clusters the lifetime behaviour would be strongly quenched by photon emission. The thermionic evaporative decay of anionic aluminium and

  6. Observations on small anionic clusters in an electrostatic ion beam trap

    Energy Technology Data Exchange (ETDEWEB)

    Eritt, Markus

    2008-10-02

    The term atomic cluster relates to compounds of at least two or three atoms. Thereby the physical properties are size dependent and the property transitions between single atoms and bulk material are not always smooth. Ion traps allow it to observe internal cluster properties independent from the influence of external forces. In this work the electron induced decay of singly negatively charged atomic clusters was observed. The dissociation cross section of the clusters is dominated by detachment of the only weakly bound outer electrons. For simple atoms at low electron energies a simple scaling law can be obtained that includes only the binding energies of the valence electrons. Nevertheless for larger sizes theoretical calculations predict so called ''giant resonances'' as dominant decay process in metal clusters. Due to mass limitations in storage rings exist so far only cross section measurements for simple anions and small negative molecules. In this work the electron detachment cross sections of small negatively charged carbon (C{sub n}{sup -} n=2-12), aluminium (Al{sub n}{sup -} n=2-7) and silver clusters (Ag{sub n}{sup -} n=1-11) were measured in an electrostatic ion beam trap. The classical scaling law, including only the binding energies of the valence electrons, turned out to be not sufficient, especially for larger clusters. In order to improve the correlation between measured and predicted values it was proposed to involve the influence of the cluster volume and the specific polarisability induced by long range coulomb interaction. For silver clusters the best agreement was obtained using a combination of the projected area reduced by the polarisability. The existence of ''giant resonances'' could not be confirmed. According to theory for clusters with a broad internal energy distribution, a power-law decay close to 1/time is expected. For some clusters the lifetime behaviour would be strongly quenched by photon

  7. Charge-sign-clustering observed in high-multiplicity, high-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Takahashi, Y.; Gregory, J.C.; Hayashi, T.

    1989-01-01

    Charge-sign distribution in 200 GeV/amu heavy-ion collisions is studied with the Magnetic-Interferometric-Emulsion-Chamber (MAGIC) for central collision events in 16 O + Pb and 32 S + Pb interactions. Charge-sign clustering is observed in most of the fully-analyzed events. A statistical 'run-test' is performed for each measured event, which shows significant deviation from a Gaussian distribution (0,1) expected for random-charge distribution. Candidates of charge clusters have 5 - 10 multiplicity of like-sign particles, and are often accompanied by opposite-sign clusters. Observed clustering of identical charges is more significant in the fragmentation region than in the central region. Two-particle Bose-Einstein interference and other effects are discussed for the run-test examination. (author)

  8. Nonlinear optical waveguides produced by MeV ion implantation in LiNbO3

    International Nuclear Information System (INIS)

    Sarkisov, S.S.; Curley, M.J.; Williams, E.K.; Ila, D.; Svetchnikov, V.L.; Zandbergen, H.W.; Zykov, G.A.; Banks, C.; Wang, J.-C.; Poker, D.B.; Hensley, D.K.

    2000-01-01

    We analyze microstructure, linear and nonlinear optical properties of planar waveguides produced by implantation of MeV Ag ions into LiNbO 3 . Linear optical properties are described by the parameters of waveguide propagation modes and optical absorption spectra. Nonlinear properties are described by the nonlinear refractive index. Operation of the implanted crystal as an optical waveguide is due to modification of the linear refractive index of the implanted region. The samples as implanted do not show any light-guiding. The implanted region has amorphous and porous microstructure with the refractive index lower than the substrate. Heat treatment of the implanted samples produces planar light-guiding layer near the implanted surface. High-resolution electron microscopy reveals re-crystallization of the host between the surface and the nuclear stopping region in the form of randomly oriented crystalline grains. They make up a light-guiding layer isolated from the bulk crystal by the nuclear stopping layer with low refractive index. Optical absorption of the sample as implanted has a peak at 430 nm. This peak is due to the surface plasmon resonance in nano-clusters of metallic silver. Heat treatment of the samples shifts the absorption peak to 545 nm. This is more likely due to the increase of the refractive index back to the value for the crystalline LiNbO 3 . The nonlinear refractive index of the samples at 532 nm (of the order of 10 -10 cm 2 W -1 ) was measured with the Z-scan technique using a picosecond laser source. Possible applications of the waveguides include ultra-fast photonic switches and modulators

  9. 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

  10. Properties of ammonium ion-water clusters: analyses of structure evolution, noncovalent interactions, and temperature and humidity effects.

    Science.gov (United States)

    Pei, Shi-Tu; Jiang, Shuai; Liu, Yi-Rong; Huang, Teng; Xu, Kang-Ming; Wen, Hui; Zhu, Yu-Peng; Huang, Wei

    2015-03-26

    Although ammonium ion-water clusters are abundant in the biosphere, some information regarding these clusters, such as their growth route, the influence of temperature and humidity, and the concentrations of various hydrated clusters, is lacking. In this study, theoretical calculations are performed on ammonium ion-water clusters. These theoretical calculations are focused on determining the following characteristics: (1) the pattern of cluster growth; (2) the percentages of clusters of the same size at different temperatures and humidities; (3) the distributions of different isomers for the same size clusters at different temperatures; (4) the relative strengths of the noncovalent interactions for clusters of different sizes. The results suggest that the dipole moment may be very significant for the ammonium ion-water system, and some new stable isomers were found. The nucleation of ammonium ions and water molecules is favorable at low temperatures; thus, the clusters observed at high altitudes might not be present at low altitudes. High humidity can contribute to the formation of large ammonium ion-water clusters, whereas the formation of small clusters may be favorable under low-humidity conditions. The potential energy surfaces (PES) of these different sized clusters are complicated and differ according to the distribution of isomers at different temperatures. Some similar structures are observed between NH4(+)(H2O)n and M(H2O)n (where M represents an alkali metal ion or water molecule); when n = 8, the clusters begin to form the closed-cage geometry. As the cluster size increases, these interactions become progressively weaker. The successive binding energy at the DF-MP2-F12/VDZ-F12 level is better than that at the PW91PW91/6-311++G(3df, 3pd) level and is consistent with the experimentally determined values.

  11. Ionization and scintillation signals produced by relativistic La ions in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, H J; Doke, T; Hitachi, H; Kikuchi, J; Lindstrom, P J; Masuda, K; Shibamura, E; Nagamiya, S

    1987-04-15

    We have observed simultaneously the ionization and scintillation signals produced by relativistic La ions in liquid argon. The two signals are highly correlated and the sums of these signals are constant with the standard deviation of 1.2% over the range of the electric field from 0 to 7.5 kV/cm. The ratio of the sum signals expressed in unit of the number of species to the value N/sub i/ + N/sub ex/ is close to unity where N/sub i/ and N/sub ex/ are the numbers of ion pairs and excitons, respectively, produced by La ions in liquid argon. The pulse height resolution of the sum of the signals is better than that of ionization or scintillation alone. Almost no quenching is found in the scintillation signal from relativistic La ions when compared to signals from lighter ions.

  12. A study on mutagenic effects of antibiotic-producers by ion implantation

    International Nuclear Information System (INIS)

    Xie Liqing; Zhang Yinfen; Chen Ruyi; Zhou Ruiying; Zhang Peiling; Ying Hengfeng; Yang Guorong; Yang Guifang

    1995-01-01

    Mutagenic effects of Streptomyces ribosidificus, Streptomyces kanamyceticus and the phage-resistant culture of Streptomyces kanamyceticus induced by N + and C + ion implantation with different doses have been investigated. The experimental results show that the death rates of antibiotic-producers increase with the increase of ion implantation dose, and the form mutation of the antibiotic-producers is rather obvious. After N + ion implantation, the titer units increase by 10%-25%, 5.2%-12.1% and 2.1%-12.75% for the above three strains respectively; while after C + ion implantation the titer units increase by 10%-16.9%, 1.05%-3.08% and 5%-20% respectively. The selected strains of Micromonospora echimospoora and Streptomyces kanamyceticus after N + ion implantation have been used in the factory. The increase of production is 20% and 12.5% respectively and marked economic benefits are obtained

  13. Characterization of an ion beam produced by extraction and acceleration of ions from a wire plasma source

    International Nuclear Information System (INIS)

    Gueroult, R.

    2011-09-01

    In this study we first model a DC low pressure wire plasma source and then characterize the properties of an ion gun derived from the plasma source. In order to study the properties of the derived ion gun, we develop a particle-in-cell code fitted to the modelling of the wire plasma source operation, and validate it by confrontation with the results of an experimental study. In light of the simulation results, an analysis of the wire discharge in terms of a collisional Child-Langmuir ion flow in cylindrical geometry is proposed. We interpret the mode transition as a natural reorganization of the discharge when the current is increased above a threshold value which is a function of the discharge voltage, the pressure and the inter-electrodes distance. In addition, the analysis of the energy distribution function of ions impacting the cathode demonstrates the ability to extract an ion beam of low energy spread around the discharge voltage assuming that the discharge is operated in its high pressure mode. An ion source prototype allowing the extraction and acceleration of ions from the wire source is then proposed. The experimental study of such a device confirms that, apart from a shift corresponding to the accelerating voltage, the acceleration scheme does not spread the ion velocity distribution function along the axis of the beam. It is therefore possible to produce tunable energy (0 - 5 keV) ion beams of various ionic species presenting limited energy dispersion (∼ 10 eV). The typical beam currents are about a few tens of micro-amperes, and the divergence of such a beam is on the order of one degree. A numerical modelling of the ion source is eventually conducted in order to identify potential optimizations of the concept. (author)

  14. Energetics and dynamics of the neutralization of clustered ions in ammonia and water vapour

    International Nuclear Information System (INIS)

    Sennhauser, E.S.; Armstrong, D.A.

    1978-01-01

    The energetics and dynamics of neutralization reactions of clustered ions in ammonia and water vapour have been analysed. Neutralization rate coefficients were calculated for the ions in ammonia and for H + .(H 2 O)sub(n) combining with various clustered anions in water vapour up to densities of 4 x 10 19 molecule cm -3 at 390 K. In the case of ammonia, calculations were also performed at 298 K. For all systems, fractional contributions of the neutralization coefficients for specific cluster sizes to the overall coefficient αsub(eff) were evaluated. The computed value of αsub(eff) for NH 3 was in reasonable agreement with experimental data in the [NH 3 ] range 0.3 to 4 x 10 19 molecule cm -3 , and general trends stemming from the effects of increasing ion mass were pointed out. Calculations of energies of individual cluster sizes indicate possible neutralization reaction mechanisms. With some exception, proton transfer is the only possible path and no H atoms should be formed. This is in general agreement with literature results for water vapour at approximately 390 K and with [H 2 O] >= 2 x 10 x 10 19 molecule cm -3 . (author)

  15. Apparatus and method for extracting power from energetic ions produced in nuclear fusion

    Science.gov (United States)

    Fisch, Nathaniel J.; Rax, Jean M.

    1994-01-01

    An apparatus and method of extracting power from energetic ions produced by nuclear fusion in a toroidal plasma to enhance respectively the toroidal plasma current and fusion reactivity. By injecting waves of predetermined frequency and phase traveling substantially in a selected poloidal direction within the plasma, the energetic ions become diffused in energy and space such that the energetic ions lose energy and amplify the waves. The amplified waves are further adapted to travel substantially in a selected toroidal direction to increase preferentially the energy of electrons traveling in one toroidal direction which, in turn, enhances or generates a toroidal plasma current. In an further adaptation, the amplified waves can be made to preferentially increase the energy of fuel ions within the plasma to enhance the fusion reactivity of the fuel ions. The described direct, or in situ, conversion of the energetic ion energy provides an efficient and economical means of delivering power to a fusion reactor.

  16. Generation of CsI cluster ions for mass calibration in matrix-assisted laser desorption/ionization mass spectrometry

    NARCIS (Netherlands)

    Lou, X.; Dongen, van J.L.J.; Meijer, E.W.

    2010-01-01

    A simple method was developed for the generation of cesium iodide (CsI) cluster ions up to m/z over 20,000 in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). Calibration ions in both positive and negative ion modes can readily be generated from a single MALDI spot of CsI(3)

  17. Bi-Directional Ion Emission from Massive Gold Cluster Impacts on Nanometric Carbon Foils

    OpenAIRE

    DeBord, J. Daniel; Della-Negra, Serge; Fernandez-Lima, Francisco A.; Verkhoturov, Stanislav V.; Schweikert, Emile A.

    2012-01-01

    Carbon cluster emission from thin carbon foils (5–40 nm) impacted by individual Aun+q cluster projectiles (95–125 qkeV, n/q = 3–200) reveals features regarding the energy deposition, projectile range, and projectile fate in matter as a function of the projectile characteristics. For the first time, the secondary ion emission from thin foils has been monitored simultaneously in both forward and backward emission directions. The projectile range and depth of emission were examined as a function...

  18. Push-and-stick mechanism for charged and excited small cluster emission under ion bombardment

    International Nuclear Information System (INIS)

    Bitensky, I.S.; Parilis, E.S.; Wojciechowski, I.A.

    1992-01-01

    The mechanism for the formation, excitation and ionization of small clusters emitted under ion bombardment is discussed. It is shown that the increased degree of ionization for the transition metal dimers, trimers and tetramers can be explained by the existence of an additional effective channel for their formation, namely the associative ionization process. A simple estimate shows that the sticking together of a fast cascade atom and the pushed out surface atom is 30-40 times more effective for dimer formation, than the recombination of two fast atoms. This push-and-stick mechanism of cluster formation could also be effective for the formation of trimers and tetramers. (orig.)

  19. FY 2000 report on the results of the research and development project for new industry creation type industrial science technologies. Cluster ion beam process technology; 2000 nendo shinki sangyo soshutsugata sangyo kagaku gijutsu kenkyu kaihatsu seido seika hokokusho. Cluster ion beam process technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Described herein are the FY 2000 results of development of cluster ion beams. This technology generates the strong ion beams of atom and molecule clusters, and irradiate them onto the solid surfaces, to create new materials or treat materials. It allows the nano-level treatment. The program for high-current cluster ion beam generation/irradiation technology for industrial purposes attains the target high-current beam of 500{mu}m. It is necessary to establish the optimum cluster size, irradiated energy and ion species for the highly functional surface treatment, for which applicable technologies, e.g., those related to time of flight and molecular dynamics, are developed. Studies on high-current, large-area irradiation technologies are started. The program for material processing technologies involves evaluation of crystalline defects formed during the beam implantation by photoluminescence spectroscopy, and studies on semiconductor surface processing technologies. The surface smoothening technology is investigated to reduce crystalline defects and stress-induced strains for difficult-to-process materials, e.g., SiC and diamond, and the good results are produced. The program for development of superflat/superhard thin film formation technology involves irradiation of the Ar ion beams during the deposition of C{sub 60}(fullerene), to produce the superhard thin film. (NEDO)

  20. Gene cluster analysis for the biosynthesis of elgicins, novel lantibiotics produced by paenibacillus elgii B69

    Directory of Open Access Journals (Sweden)

    Teng Yi

    2012-03-01

    Full Text Available Abstract Background The recent increase in bacterial resistance to antibiotics has promoted the exploration of novel antibacterial materials. As a result, many researchers are undertaking work to identify new lantibiotics because of their potent antimicrobial activities. The objective of this study was to provide details of a lantibiotic-like gene cluster in Paenibacillus elgii B69 and to produce the antibacterial substances coded by this gene cluster based on culture screening. Results Analysis of the P. elgii B69 genome sequence revealed the presence of a lantibiotic-like gene cluster composed of five open reading frames (elgT1, elgC, elgT2, elgB, and elgA. Screening of culture extracts for active substances possessing the predicted properties of the encoded product led to the isolation of four novel peptides (elgicins AI, AII, B, and C with a broad inhibitory spectrum. The molecular weights of these peptides were 4536, 4593, 4706, and 4820 Da, respectively. The N-terminal sequence of elgicin B was Leu-Gly-Asp-Tyr, which corresponded to the partial sequence of the peptide ElgA encoded by elgA. Edman degradation suggested that the product elgicin B is derived from ElgA. By correlating the results of electrospray ionization-mass spectrometry analyses of elgicins AI, AII, and C, these peptides are deduced to have originated from the same precursor, ElgA. Conclusions A novel lantibiotic-like gene cluster was shown to be present in P. elgii B69. Four new lantibiotics with a broad inhibitory spectrum were isolated, and these appear to be promising antibacterial agents.

  1. Investigation of the composition of an ion beam produced using a multi arc ion source

    Energy Technology Data Exchange (ETDEWEB)

    Engelko, V [Efremov Institute of Electrophysical Apparatus, St. Petersburg (Russian Federation); Giese, H; Schalk, S [Forschungszentrum Karlsruhe (Germany). INR; Mishin, M; Tsibin, O Y [St. Petersburg State Technical Univ. (Russian Federation)

    1997-12-31

    Complementing the diode and beam transport optimization studies currently performed at FZK Karlsruhe on the proton-beam-facility PROFA, supplementary investigations were run at the St. Petersburg State University, focusing on ion beam divergence and composition measurements using the TOF techniques. To ensure direct transferability of the results to the PROFA facility, these measurements were made on a scaled-down replica of the PROFA diode, comprising an array of small polyethylene flash-over plasma sources and a grid extraction system. Only the results of the beam composition measurements are presented, and the following conclusions are made: (i) The ion beam contains H and C ions and heavier constituents that remain to be identified. (ii) The beam composition changes significantly with the total number of shots: While H{sup +} ions predominated in the starting phase of the experiments, heavier components outweighed them later on, presumably due to hydrogen depletion of the surface layer of the anode polyethylene units. (iii) Reconditioning of the polyethylene units may be possible by running the diode at higher currents (self-cleaning) or by cutting off a surface layer. (author). 7 figs., 3 refs.

  2. Observation and study of centrally produced pion clusters in 28.5-GeV/c p-p interactions

    International Nuclear Information System (INIS)

    Erwin, A.R.; Harvey, E.H.; Larson, G.P.; Collins, G.B.; Ficenec, J.R.; Stringfellow, B.C.; Trower, W.P.; Gutay, L.J.; Laasanen, A.; Willmann, R.B.; Anderson, E.W.; Fisher, G.P.; Lazuras, E.; von Lindern, L.; Ramanauskas, A.; Schubelin, P.; Thorndike, A.M.; Turkot, F.

    1976-01-01

    A double-arm spectrometer is used to identify a pion cluster produced in central p-p collisions at 28.5 GeV/c. Cluster properties studied are angular momentum, quantum statistics, multiplicity, and effective mass. There is some speculation on the production mechanism

  3. Are clusters important in understanding the mechanisms in atmospheric pressure ionization? Part 1: Reagent ion generation and chemical control of ion populations.

    Science.gov (United States)

    Klee, Sonja; Derpmann, Valerie; Wißdorf, Walter; Klopotowski, Sebastian; Kersten, Hendrik; Brockmann, Klaus J; Benter, Thorsten; Albrecht, Sascha; Bruins, Andries P; Dousty, Faezeh; Kauppila, Tiina J; Kostiainen, Risto; O'Brien, Rob; Robb, Damon B; Syage, Jack A

    2014-08-01

    It is well documented since the early days of the development of atmospheric pressure ionization methods, which operate in the gas phase, that cluster ions are ubiquitous. This holds true for atmospheric pressure chemical ionization, as well as for more recent techniques, such as atmospheric pressure photoionization, direct analysis in real time, and many more. In fact, it is well established that cluster ions are the primary carriers of the net charge generated. Nevertheless, cluster ion chemistry has only been sporadically included in the numerous proposed ionization mechanisms leading to charged target analytes, which are often protonated molecules. This paper series, consisting of two parts, attempts to highlight the role of cluster ion chemistry with regard to the generation of analyte ions. In addition, the impact of the changing reaction matrix and the non-thermal collisions of ions en route from the atmospheric pressure ion source to the high vacuum analyzer region are discussed. This work addresses such issues as extent of protonation versus deuteration, the extent of analyte fragmentation, as well as highly variable ionization efficiencies, among others. In Part 1, the nature of the reagent ion generation is examined, as well as the extent of thermodynamic versus kinetic control of the resulting ion population entering the analyzer region.

  4. Ag clustering investigation in laser irradiated ion-exchanged glasses by optical and vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trave, E., E-mail: enrico.trave@unive.it [Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venezia, Dorsoduro 2137, I-30123 Venezia (Italy); Cattaruzza, E.; Gonella, F.; Calvelli, P. [Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venezia, Dorsoduro 2137, I-30123 Venezia (Italy); Quaranta, A. [Department of Materials Engineering and Industrial Technologies, University of Trento, via Mesiano 77, I-38050 Povo (Italy); Rahman, A.; Mariotto, G. [Department of Computer Science, University of Verona, Strada le Grazie 15, 37134 Verona (Italy)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We modify the properties of Ag{sup +} exchanged glasses by thermal and laser treatment. Black-Right-Pointing-Pointer The induced microstructural changes are analyzed by optical and Raman spectroscopy. Black-Right-Pointing-Pointer Ag-based species in the glass show a peculiar PL activity in the UV-Vis range. Black-Right-Pointing-Pointer Raman and OA analysis allow for determining the Ag cluster size evolution. Black-Right-Pointing-Pointer Laser processing leads to different cluster formation and fragmentation mechanisms. - Abstract: Ion exchange process is widely used to dope silicate glass layers with silver for several applications, ranging from light waveguide to nanostructured composite glass fabrication. The silver-doped structure and its physical properties depend on the preparation parameters as well as on subsequent treatments. In particular, laser irradiation of the ion exchanged glasses has been demonstrated to be an effective tool to control cluster size and size distribution. Nevertheless, a complete comprehension of the basic phenomena and a systematic characterization of these systems are still lacking. In this paper, an extended optical characterization is presented for soda-lime glass slides, doped with silver by Ag{sup +}-Na{sup +} ion exchange, thermally treated and irradiated with a Nd:YAG laser beam at different wavelengths, and for different energy density. The samples were characterized by various spectroscopic techniques, namely, optical absorption, photoluminescence and micro-Raman analysis. The availability of all these characterization techniques allowed pointing out a suitable scenario for the Ag clustering evolution as a function of the ion exchange, annealing and laser irradiation parameters.

  5. Properties of Laser-Produced Highly Charged Heavy Ions for Direct Injection Scheme

    CERN Document Server

    Sakakibara, Kazuhiko; Hayashizaki, Noriyosu; Ito, Taku; Kashiwagi, Hirotsugu; Okamura, Masahiro

    2005-01-01

    To accelerate highly charged intense ion beam, we have developed the Direct Plasma Injection Scheme (DPIS) with laser ion source. In this scheme an ion beam from a laser ion source is injected directly to a RFQ linac without a low energy beam transport (LEBT) and the beam loss in the LEBT can be avoided. We achieved high current acceleration of carbon ions (60mA) by DPIS with the high current optimized RFQ. As the next setp we will use heavier elements like Ag, Pb, Al and Cu as target in LIS (using CO2, Nd-YAG or other laser) for DPIS and will examine properties of laser-produced plasma (the relationship of between charge state and laser power density, the current dependence of the distance from the target, etc).

  6. Nuclear tracks in CR-39 produced by carbon, oxygen, aluminium and titanium ions.

    Science.gov (United States)

    Rickards, J; Romo, V; Golzarri, J I; Espinosa, G

    2002-01-01

    This work describes the response of CR-39 (allyl diglycol polycarbonate) to different ions (C, O, Al and Ti) produced by the Instituto de Fisica 3 MV 9SDH-2 Pelletron accelerator and backscattered from a thin Au film on a C support. The ion energies were chosen in series such that the ranges of the different ions in the detector were 2, 3, 4, 5, 6, 7 and 8 microm respectively for each series. Once exposed, the detectors were etched with a solution of 6.25 M KOH at 60 degrees C, and the reading was carried out using a digital image analysis system. An analysis of the measured track diameters of all the types of ions indicates that, for a given range, track kinetics are independent of type of ion, energy and stopping power.

  7. Intrinsic rotation produced by ion orbit loss and X-loss

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, W. M. [Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Boedo, J. A. [University of California - San Diego, San Diego, California 92093 (United States); Evans, T. E.; Groebner, R. J. [General Atomics, San Diego, California 92186 (United States); Grierson, B. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08453 (United States)

    2012-11-15

    A practical calculation model for the intrinsic rotation imparted to the edge plasma by the directionally preferential loss of ions on orbits that cross the last closed flux surface is presented and applied to calculate intrinsic rotation in several DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] discharges. The intrinsic rotation produced by ion loss is found to be sensitive to the edge temperature and radial electric field profiles, which has implications for driving intrinsic rotation in future large tokamaks.

  8. Bi-Directional Ion Emission from Massive Gold Cluster Impacts on Nanometric Carbon Foils.

    Science.gov (United States)

    Debord, J Daniel; Della-Negra, Serge; Fernandez-Lima, Francisco A; Verkhoturov, Stanislav V; Schweikert, Emile A

    2012-04-12

    Carbon cluster emission from thin carbon foils (5-40 nm) impacted by individual Au(n) (+q) cluster projectiles (95-125 qkeV, n/q = 3-200) reveals features regarding the energy deposition, projectile range, and projectile fate in matter as a function of the projectile characteristics. For the first time, the secondary ion emission from thin foils has been monitored simultaneously in both forward and backward emission directions. The projectile range and depth of emission were examined as a function of projectile size, energy, and target thickness. A key finding is that the massive cluster impact develops very differently from that of a small polyatomic projectile. The range of the 125 qkeV Au(100q) (+q) (q ≈ 4) projectile is estimated to be 20 nm (well beyond the range of an equal velocity Au(+)) and projectile disintegration occurs at the exit of even a 5 nm thick foil.

  9. Polar cap ion beams during periods of northward IMF: Cluster statistical results

    Directory of Open Access Journals (Sweden)

    R. Maggiolo

    2011-05-01

    Full Text Available Above the polar caps and during prolonged periods of northward IMF, the Cluster satellites detect upward accelerated ion beams with energies up to a few keV. They are associated with converging electric field structures indicating that the acceleration is caused by a quasi-static field-aligned electric field that can extend to altitudes higher than 7 RE (Maggiolo et al., 2006; Teste et al., 2007. Using the AMDA science analysis service provided by the Centre de Données de la Physique des Plasmas, we have been able to extract about 200 events of accelerated upgoing ion beams above the polar caps from the Cluster database. Most of these observations are taken at altitudes lower than 7 RE and in the Northern Hemisphere. We investigate the statistical properties of these ion beams. We analyze their geometry, the properties of the plasma populations and of the electric field inside and around the beams, as well as their dependence on solar wind and IMF conditions. We show that ~40 % of the ion beams are collocated with a relatively hot and isotropic plasma population. The density and temperature of the isotropic population are highly variable but suggest that this plasma originates from the plasma sheet. The ion beam properties do not change significantly when the isotropic, hot background population is present. Furthermore, during one single polar cap crossing by Cluster it is possible to detect upgoing ion beams both with and without an accompanying isotropic component. The analysis of the variation of the IMF BZ component prior to the detection of the beams indicates that the delay between a northward/southward turning of IMF and the appearance/disappearance of the beams is respectively ~2 h and 20 min. The observed electrodynamic characteristics of high altitude polar cap ion beams suggest that they are closely connected to polar cap auroral arcs. We discuss the implications of these Cluster observations above the polar cap on the magnetospheric

  10. Submicroscopic pores grafted using the residual sites produced by swift heavy ions

    International Nuclear Information System (INIS)

    Mazzei, R.; Betz, N.; Bermudez, G. Garcia; Massa, G.; Smolko, E.

    2005-01-01

    To produce nuclear track membranes (NTM) with submicroscopic pores poly(vinylidene difluoride) (PVDF) foils were irradiated with Cl, Ag and Pb ions. Then they were chemically etched for different times and grafted with acrylic acid. The grafting yields were determined by weight measurements as a function of ion fluence, etching time and also analysed using Fourier transform infrared spectroscopy. Both measurements suggest that the acrylic acid was grafted on the pore wall of the NTM using the active sites left by the ion beam

  11. Measurements of hydrogen gas stopping efficiency for tin ions from laser-produced plasma

    Science.gov (United States)

    Abramenko, D. B.; Spiridonov, M. V.; Krainov, P. V.; Krivtsun, V. M.; Astakhov, D. I.; Medvedev, V. V.; van Kampen, M.; Smeets, D.; Koshelev, K. N.

    2018-04-01

    Experimental studies of stopping of ion fluxes from laser-produced plasma by a low-pressure gas atmosphere are presented. A modification of the time-of-flight spectroscopy technique is proposed for the stopping cross-sectional measurements in the ion energy range of 0.1-10 keV. The application of the proposed technique is demonstrated for Sn ion stopping by H2 gas. This combination of elements is of particular importance for the development of plasma-based sources of extreme ultraviolet radiation for lithographic applications.

  12. Molecular dynamics simulations with electronic stopping can reproduce experimental sputtering yields of metals impacted by large cluster ions

    Science.gov (United States)

    Tian, Jiting; Zhou, Wei; Feng, Qijie; Zheng, Jian

    2018-03-01

    An unsolved problem in research of sputtering from metals induced by energetic large cluster ions is that molecular dynamics (MD) simulations often produce sputtering yields much higher than experimental results. Different from the previous simulations considering only elastic atomic interactions (nuclear stopping), here we incorporate inelastic electrons-atoms interactions (electronic stopping, ES) into MD simulations using a friction model. In this way we have simulated continuous 45° impacts of 10-20 keV C60 on a Ag(111) surface, and found that the calculated sputtering yields can be very close to the experimental results when the model parameter is appropriately assigned. Conversely, when we ignore the effect of ES, the yields are much higher, just like the previous studies. We further expand our research to the sputtering of Au induced by continuous keV C60 or Ar100 bombardments, and obtain quite similar results. Our study indicates that the gap between the experimental and the simulated sputtering yields is probably induced by the ignorance of ES in the simulations, and that a careful treatment of this issue is important for simulations of cluster-ion-induced sputtering, especially for those aiming to compare with experiments.

  13. Spectral measurements of few-electron uranium ions produced and trapped in a high-energy electron beam ion trap

    International Nuclear Information System (INIS)

    Beiersdorfer, P.

    1994-01-01

    Measurements of 2s l/2 -2p 3/2 electric dipole and 2p 1/2 -2p 3/2 magnetic dipole and electric quadrupole transitions in U 82+ through U 89+ have been made with a high-resolution crystal spectrometer that recorded the line radiation from stationary ions produced and trapped in a high-energy electron beam ion trap. From the measurements we infer -39.21 ± 0.23 eV for the QED contribution to the 2s 1/2 -2p 3/2 transition energy of lithiumlike U 89+ . A comparison between our measurements and various computations illustrates the need for continued improvements in theoretical approaches for calculating the atomic structure of ions with two or more electrons in the L shell

  14. Formation time of hadrons and density of matter produced in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Pisut, J.; Zavada, P.

    1994-06-01

    Densities of interacting hadronic matter produced in Oxygen-Lead and Sulphur-Lead collisions at 200 GeV/nucleon are estimated as a function of the formation time of hadrons. Uncertainties in our knowledge of the critical temperature T c and of the formation time of hadrons τ 0 permit at present three scenarios: an optimistic one (QGP has already been produced in collisions of Oxygen and Sulphur with heavy ions and will be copiously in Lead collisions), a pessimistic one (QGP cannot be produced at 200 GeV/nucleon) and an intermediate one (QGP has not been produced in Oxygen and Sulphur Interactions with heavy ions and will be at best produced only marginally in Pb-collisions). The last option is found to be the most probable. (author)

  15. Properties of clusters in the gas phase: V. Complexes of neutral molecules onto negative ions

    International Nuclear Information System (INIS)

    Keesee, R.G.; Lee, N.; Castleman, A.W. Jr.

    1980-01-01

    Ion--molecules association reactions of the form A - (B)/sub n1/-+B=A - (B)/sub n/ were studied over a range of temperatures in the gas phase using high pressure mass spectrometry. Enthalpy and entropy changes were determined for the stepwise clustering reactions of (1) sulfur dioxide onto Cl - , I - , and NO 2 - with n ranging from one to three or four, and onto SO 2 - and SO 3 - with n equal to one; and (2) carbon dioxide onto Cl - , I - , NO 2 - , CO 3 - , and SO 3 - with n equal to one. From these data and earlier hydration results, the order of the magnitude of the enthalpy changes on the association of the first neutral for a series of negative ions was found to parallel the gas-phase basicity of those anions. For any given ion, the relative order of the addition enthalpies among the neutrals was found to be dependent on the polarizabilities of the neutrals and on the covalency in the ion-neutral bond. Dispersion of charge via covalent bonding was found to affect significantly the succeeding clustering steps

  16. Field Observation of the Green Ocean Amazon. Neutral Cluster Air Ion Spectrometer (NAIS) Final Campaign Summary

    Energy Technology Data Exchange (ETDEWEB)

    Petaja, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Backman, J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Manninen, H. E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wimmer, D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-01

    The neutral cluster and air ion spectrometer (NAIS) was deployed to the T3 site for Intensive Operations Periods 1 and 2 (IOP1 and IOP2). The NAIS is an instrument that measures aerosol particle and ion number size distributions in the mobility diameter range of 0.8 to 42 nm, corresponding to electrical mobility range between 3.2 and 0.0013 cm2 V-1 s-1. New particle formation (NPF) events were detected using the NAIS at the T3 field site during IOP1 and IOP2. Secondary NPF is a globally important source of aerosol number. To fully explain atmospheric NPF and subsequent growth, we need to directly measure the initial steps of the formation processes in different environments, including rain forest. Particle formation characteristics, such as formation and growth rates, were used as indicators of the relevant processes and participating compounds in the initial formation. In a case of parallel ion and neutral cluster measurements, we estimated the relative contribution of ion-induced and neutral nucleation to the total particle formation.

  17. Major signal suppression from metal ion clusters in SFC/ESI-MS - Cause and effects.

    Science.gov (United States)

    Haglind, Alfred; Hedeland, Mikael; Arvidsson, Torbjörn; Pettersson, Curt E

    2018-05-01

    The widening application area of SFC-MS with polar analytes and water-containing samples facilitates the use of quick and simple sample preparation techniques such as "dilute and shoot" and protein precipitation. This has also introduced new polar interfering components such as alkali metal ions naturally abundant in e.g. blood plasma and urine, which have shown to be retained using screening conditions in SFC/ESI-TOF-MS and causing areas of major ion suppression. Analytes co-eluting with these clusters will have a decreased signal intensity, which might have a major effect on both quantification and identification. When investigating the composition of the alkali metal clusters using accurate mass and isotopic pattern, it could be concluded that they were previously not described in the literature. Using NaCl and KCl standards and different chromatographic conditions, varying e.g. column and modifier, the clusters proved to be formed from the alkali metal ions in combination with the alcohol modifier and make-up solvent. Their compositions were [(XOCH 3 ) n  + X] + , [(XOH) n  + X] + , [(X 2 CO 3 ) n  + X] + and [(XOOCOCH 3 ) n  + X] + for X = Na + or K + in ESI+. In ESI-, the clusters depended more on modifier, with [(XCl) n  + Cl] - and [(XOCH 3 ) n  + OCH 3 ] - mainly formed in pure methanol and [(XOOCH) n  + OOCH] - when 20 mM NH 4 Fa was added. To prevent the formation of the clusters by avoiding methanol as modifier might be difficult, as this is a widely used modifier providing good solubility when analyzing polar compounds in SFC. A sample preparation with e.g. LLE would remove the alkali ions, however also introducing a time consuming and discriminating step into the method. Since the alkali metal ions were retained and affected by chromatographic adjustments as e.g. mobile phase modifications, a way to avoid them could therefore be chromatographic tuning, when analyzing samples containing them. Copyright © 2018 Elsevier

  18. Screening on the high yield validamycin producing strain by implantation with N+ and Ti+ ion source

    International Nuclear Information System (INIS)

    Yu Long; An Xiao

    2007-01-01

    In order to compared the mutagenic effects of the validamycin producing the strain (Streptomyces hygroscopicus var. Jingganggensis Yen.) was implanted with two kinds of ion sources. The results showed that when two kinds of ion sources implanted into the strain by turns, more positive mutants and higher yield would be acquired. Using this method, a high-yielding strain B1-3 was obtained, which produce the titer of validamycin A of 21514, and was 54.4% higher than that of the original strain. (authors)

  19. Probing potential Li-ion battery electrolyte through first principles simulation of atomic clusters

    Science.gov (United States)

    Kushwaha, Anoop Kumar; Sahoo, Mihir Ranjan; Nayak, Saroj

    2018-04-01

    Li-ion battery has wide area of application starting from low power consumer electronics to high power electric vehicles. However, their large scale application in electric vehicles requires further improvement due to their low specific power density which is an essential parameter and is closely related to the working potential windows of the battery system. Several studies have found that these parameters can be taken care of by considering different cathode/anode materials and electrolytes. Recently, a unique approach has been reported on the basis of cluster size in which the use of Li3 cluster has been suggested as a potential component of the battery electrode material. The cluster based approach significantly enhances the working electrode potential up to 0.6V in the acetonitrile solvent. In the present work, using ab-initio quantum chemical calculation and the dielectric continuum model, we have investigated various dielectric solvent medium for the suitable electrolyte for the potential component Li3 cluster. This study suggests that high dielectric electrolytic solvent (ethylene carbonate and propylene carbonate) could be better for lithium cluster due to improvement in the total electrode potential in comparison to the other dielectric solvent.

  20. Novel radial vanadium pentoxide nanobelt clusters for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yanping; Zhong, Wenwu [Department of Physics and Electronic Engineering, Taizhou University, Taizhou, Zhejiang 318000 (China); Du, Yinxiao, E-mail: duyinxiao@zzia.edu.cn [Department of Mathematics and Physics, Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou 450015 (China); Yuan, Q.X. [Department of Mathematics and Physics, Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou 450015 (China); Wang, Xu [School of Microelectronics, Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xidian University, Xi' an 710071 (China); Jia, Renxu, E-mail: rxjia@mail.xidian.edu.cn [School of Microelectronics, Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xidian University, Xi' an 710071 (China)

    2015-06-05

    Highlights: • Radial V{sub 2}O{sub 5} nanobelt clusters were synthesized by a novel hydrothermal process. • The V{sub 2}O{sub 5} clusters are single crystallites with [0 1 0] growth direction. • Specific discharge capacity of V{sub 2}O{sub 5} is 134 mA h/g coupled with good cycle stability. - Abstract: This paper reports the synthesis, characterization and Li-ion intercalation properties of moundlily-like radial vanadium pentoxide (V{sub 2}O{sub 5}) nanobelt clusters. The V{sub 2}O{sub 5} nanobelt clusters was successfully synthesized by a novel soft template assisted hydrothermal process followed by thermal annealing. The as-prepared products were characterized by X-ray diffraction, thermogravimetric analysis, FT-IR spectrometry, scanning electron microscopy and high resolution transmission electron microscopy. The obtained V{sub 2}O{sub 5} possesses a single-crystalline structure with a preferred orientation along the [0 1 0] crystal plane. Electrochemical analysis shows that the specific discharge capacity of the V{sub 2}O{sub 5} nanobelt clusters reaches 134 mA h/g at a current density of 2 A/g coupled with good cycle stability.

  1. Near-surface hydrogen depletion of diamond-like carbon films produced by direct ion deposition

    Science.gov (United States)

    Markwitz, Andreas; Gupta, Prasanth; Mohr, Berit; Hübner, René; Leveneur, Jerome; Zondervan, Albert; Becker, Hans-Werner

    2016-03-01

    Amorphous atomically flat diamond-like carbon (DLC) coatings were produced by direct ion deposition using a system based on a Penning ion source, butane precursor gas and post acceleration. Hydrogen depth profiles of the DLC coatings were measured with the 15N R-NRA method using the resonant nuclear reaction 1H(15N, αγ)12C (Eres = 6.385 MeV). The films produced at 3.0-10.5 kV acceleration voltage show two main effects. First, compared to average elemental composition of the film, the near-surface region is hydrogen depleted. The increase of the hydrogen concentration by 3% from the near-surface region towards the bulk is attributed to a growth model which favours the formation of sp2 hybridised carbon rich films in the film formation zone. Secondly, the depth at which the maximum hydrogen concentration is measured increases with acceleration voltage and is proportional to the penetration depth of protons produced by the ion source from the precursor gas. The observed effects are explained by a deposition process that takes into account the contributions of ion species, hydrogen effusion and preferential displacement of atoms during direct ion deposition.

  2. Near-surface hydrogen depletion of diamond-like carbon films produced by direct ion deposition

    Energy Technology Data Exchange (ETDEWEB)

    Markwitz, Andreas, E-mail: A.Markwitz@gns.cri.nz [GNS Science, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology (New Zealand); Gupta, Prasanth [GNS Science, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology (New Zealand); Mohr, Berit [GNS Science, Lower Hutt (New Zealand); Hübner, René [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (Germany); Leveneur, Jerome; Zondervan, Albert [GNS Science, Lower Hutt (New Zealand); Becker, Hans-Werner [RUBION, Ruhr-University Bochum (Germany)

    2016-03-15

    Amorphous atomically flat diamond-like carbon (DLC) coatings were produced by direct ion deposition using a system based on a Penning ion source, butane precursor gas and post acceleration. Hydrogen depth profiles of the DLC coatings were measured with the 15N R-NRA method using the resonant nuclear reaction {sup 1}H({sup 15}N, αγ){sup 12}C (E{sub res} = 6.385 MeV). The films produced at 3.0–10.5 kV acceleration voltage show two main effects. First, compared to average elemental composition of the film, the near-surface region is hydrogen depleted. The increase of the hydrogen concentration by 3% from the near-surface region towards the bulk is attributed to a growth model which favours the formation of sp{sup 2} hybridised carbon rich films in the film formation zone. Secondly, the depth at which the maximum hydrogen concentration is measured increases with acceleration voltage and is proportional to the penetration depth of protons produced by the ion source from the precursor gas. The observed effects are explained by a deposition process that takes into account the contributions of ion species, hydrogen effusion and preferential displacement of atoms during direct ion deposition.

  3. The influence of target structure on topographical features produced by ion beam sputtering

    International Nuclear Information System (INIS)

    Whitton, J.L.; Grant, W.A.

    1981-01-01

    Ion beam erosion of solid surfaces often results in the development of distinctive topographical features. The relationship between the type of features formed by ion erosion and target structure has been investigated. Single crystals of copper and nickel and the amorphous alloy Metglas have been bombarded to high doses (approx. >=10 19 ions cm -2 ) with 40 keV Ar + and P + . Topography changes were monitored using SEM and structural changes by TEM. Targets that retain their long range crystallinity show sharply defined, regular features that are related to the target structure. Targets that are highly disordered, either intrinsically or as a result of the ion bombardment, produce diffuse, smaller features. Those differences are observed at all stages in topographical evolution. (orig.)

  4. Angular distribution of ions and extreme ultraviolet emission in laser-produced tin droplet plasma

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hong; Duan, Lian; Lan, Hui [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Wang, Xinbing, E-mail: xbwang@hust.edu.cn; Chen, Ziqi; Zuo, Duluo [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Lu, Peixiang [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-05-21

    Angular-resolved ion time-of-flight spectra as well as extreme ultraviolet radiation in laser-produced tin droplet plasma are investigated experimentally and theoretically. Tin droplets with a diameter of 150 μm are irradiated by a pulsed Nd:YAG laser. The ion time-of-flight spectra measured from the plasma formed by laser irradiation of the tin droplets are interpreted in terms of a theoretical elliptical Druyvesteyn distribution to deduce ion density distributions including kinetic temperatures of the plasma. The opacity of the plasma for extreme ultraviolet radiation is calculated based on the deduced ion densities and temperatures, and the angular distribution of extreme ultraviolet radiation is expressed as a function of the opacity using the Beer–Lambert law. Our results show that the calculated angular distribution of extreme ultraviolet radiation is in satisfactory agreement with the experimental data.

  5. Angular distribution of ions and extreme ultraviolet emission in laser-produced tin droplet plasma

    International Nuclear Information System (INIS)

    Chen, Hong; Duan, Lian; Lan, Hui; Wang, Xinbing; Chen, Ziqi; Zuo, Duluo; Lu, Peixiang

    2015-01-01

    Angular-resolved ion time-of-flight spectra as well as extreme ultraviolet radiation in laser-produced tin droplet plasma are investigated experimentally and theoretically. Tin droplets with a diameter of 150 μm are irradiated by a pulsed Nd:YAG laser. The ion time-of-flight spectra measured from the plasma formed by laser irradiation of the tin droplets are interpreted in terms of a theoretical elliptical Druyvesteyn distribution to deduce ion density distributions including kinetic temperatures of the plasma. The opacity of the plasma for extreme ultraviolet radiation is calculated based on the deduced ion densities and temperatures, and the angular distribution of extreme ultraviolet radiation is expressed as a function of the opacity using the Beer–Lambert law. Our results show that the calculated angular distribution of extreme ultraviolet radiation is in satisfactory agreement with the experimental data

  6. On the nature of the disordered layer produced by ion implantation

    International Nuclear Information System (INIS)

    Zellama, K.; Germain, P.; Squelard, S.; Bourgoin, J.C.; Piaguet, J.; Robic, J.Y.

    1978-01-01

    The aim of this communication is to compare some thermodynamic parameters measured in amorphous layers produced by evaporation and in disordered layers produced by ion implantation (which will be called implanted layers). The thermodynamics parameters studied are: the temperature of the annealing stages (reflecting the activation energies for atomic rearrangement) and the activation energy of the growth rate for crystallization. This investigation has been performed in germanium because the crystallization in this material has been extensively studied. (author)

  7. Application of laser produced ion beams to nuclear analysis of materials

    International Nuclear Information System (INIS)

    Mima, K.; Fujita, K.; Azuma, H.; Yamazaki, A.; Kato, Y.; Okuda, C.; Ukyo, Y.; Sawada, H.; Gonzalez-Arrabal, R.; Perlado, J. M.; Nishimura, H.; Nakai, S.

    2013-01-01

    The ion beam driven nuclear analysis has been developed for many years by using various electrostatic accelerators. A proton micro-beam with the beam diameter of ∼1.5 μm at Takasaki Ion Acceleration for Advanced Radiation Application (TIARA), JAEA was used to analyze the positive electrode of the Li-ion battery with PIGE and PIXE. WThe PIGE and PIXE images of Li and Ni respectively for Li x Ni 0.8 Co 0.15 Al 0.05 O 2 (x = 0.75 ∼ 1.0) anodes have been taken. The PIGE images of Li x Ni 0.8 Co 0.15 Al 0.05 O 2 particles and the depth profile of the Li density have been obtained with high spatial resolution (a few μm). The images of the Li density distribution are very useful for the RandD of the Li ion battery. In order to make the in-situ ion beam analysis of the Li battery possible, a compact accelerator for a high quality MeV proton beam is necessary. Form this point of view, the diagnostics of Li ion battery is an appropriate field for the applications of laser produced ion beams. (authors)

  8. Physical property of disordered-GaAs produced by ion implantation

    International Nuclear Information System (INIS)

    Nojima, Shunji

    1979-01-01

    The properties of disordered-GaAs produced by ion implantation and its annealing behaviors are investigated for ion species of H, Be, P, and As, from the viewpoints of both the electrical property and the physical structure of the disordered layer. From the study of the electron diffraction for implanted layers and of the conductivity due to defects as a function of dose, depth, measuring temperature, and annealing temperature, the following two facts are clarified: first, the conductivity due to defects can be a good measure for the degree of disorder in GaAs produced by ion implantation, when it is less than --1 Ω -1 cm -1 . Second, the localized states originating from defects are distributed with the same density in the high dose implanted layer, in spite of the degree of disorder in the physical structure. (author)

  9. Observation of transient lattice vacancies produced during high-energy ion irradiation of Ni foils

    International Nuclear Information System (INIS)

    Tsuchida, Hidetsugu; Iwai, Takeo; Awano, Misa; Kishida, Mutsumi; Katayama, Ichiro; Jeong, Sun-Chang; Ogawa, Hidemi; Sakamoto, Naoki; Komatsu, Masao; Itoh, Akio

    2007-01-01

    Real-time positron annihilation spectroscopy has been applied for the first time for the investigation of lattice vacancies produced during ion irradiation. Measurements were performed for thin nickel foils irradiated with 2.5 MeV C ions. Doppler broadenings of positron annihilation γ-rays were measured alternately during beam-on and beam-off conditions. It was found that the Doppler broadening line-shape parameter measured during irradiation is larger than those obtained before and after irradiation. This evidently implies that transient or non-survivable vacancy defects are produced during ion irradiation. On the other hand, no such significant change in the line-shape parameter was observed for other face-centred-cubic metal forms of aluminium

  10. Transverse Momentum Distribution of Vector Mesons Produced in Ultraperipheral Relativistic Heavy Ion Collisions

    International Nuclear Information System (INIS)

    Hencken, Kai; Baur, Gerhard; Trautmann, Dirk

    2006-01-01

    We study the transverse momentum distribution of vector mesons produced in ultraperipheral relativistic heavy ion collisions (UPCs). In UPCs there is no strong interaction between the nuclei, and the vector mesons are produced in photon-nucleus collisions where the (quasireal) photon is emitted from the other nucleus. Exchanging the role of both ions leads to interference effects. A detailed study of the transverse momentum distribution, which is determined by the transverse momentum of the emitted photon, the production process on the target, and the interference effect, is done. We study the unrestricted cross section and the one with an additional electromagnetic excitation of one or both ions; in the latter case small impact parameters are emphasized

  11. Flow injection determination of metronidazole through spectrophotometric measurement of the nitrite ion produced upon alkaline hydrolysis

    Directory of Open Access Journals (Sweden)

    Simões Simone S.

    2006-01-01

    Full Text Available A new method for metronidazole determination, based on spectrometric monitoring of a diazonium salt produced in-line by alkaline hydrolysis released nitrite ions, was developed and successfully applied to pharmaceutical tablets (r = 0.9993, 2.0-20.0 mg L-1, DL = 0.7 mg L-1 with no interference from common ingredients accompanying the drug.

  12. Study of small carbon and semiconductor clusters using negative ion threshold photodetachment spectroscopy

    International Nuclear Information System (INIS)

    Arnold, C.C.

    1994-08-01

    The bonding and electronics of several small carbon and semiconductor clusters containing less than ten atoms are probed using negative ion threshold photodetachment (zero electron kinetic energy, or ZEKE) spectroscopy. ZEKE spectroscopy is a particularly advantageous technique for small cluster study, as it combines mass selection with good spectroscopic resolution. The ground and low-lying electronic states of small clusters in general can be accessed by detaching an electron from the ground anion state. The clusters studied using this technique and described in this work are C 6 - /C 6 , Si n - /Si n (n = 2, 3, 4), Ge 2 - /Ge 2 , In 2 P - /In 2 P,InP 2 - /InP 2 , and Ga 2 As - . The total photodetachment cross sections of several other small carbon clusters and the ZEKE spectrum of the I - ·CH 3 I S N 2 reaction complex are also presented to illustrate the versatility of the experimental apparatus. Clusters with so few atoms do not exhibit bulk properties. However, each specie exhibits bonding properties that relate to the type of bonding found in the bulk. C 6 , as has been predicted, exhibits a linear cumulenic structure, where double bonds connect all six carbon atoms. This double bonding reflects how important π bonding is in certain phases of pure carbon (graphite and fullerenes). The symmetric stretch frequencies observed in the C 6 - spectra, however, are in poor agreement with the calculated values. Also observed as sharp structure in total photodetachment cross section scans was an excited anion state bound by only ∼40 cm -1 relative to the detachment continuum. This excited anion state appears to be a valence bound state, possible because of the high electron affinity of C 6 , and the open shell of the anion

  13. Concomitant formation of different nature clusters and hardening in reactor pressure vessel steels irradiated by heavy ions

    International Nuclear Information System (INIS)

    Fujii, K.; Fukuya, K.; Hojo, T.

    2013-01-01

    Specimens of A533B steels containing 0.04, 0.09 and 0.21 wt%Cu were irradiated at 290 °C to 3 dpa with 3 MeV Fe ions and subjected to atom probe analyses, transmission electron microscopy observations and hardness measurements. The atom probe analysis results showed that two types of solute clusters were formed: Cu-enriched clusters containing Mn, Ni and Si atoms as irradiation-enhanced solute atom clusters and Mn/Ni/Si-enriched clusters as irradiation-induced solute atom clusters. Both cluster types occurred in the highest Cu-content steel and the ratio of Mn/Ni/Si-enriched clusters to Cu-enriched clusters increased with irradiation doses. It was confirmed that the cluster formation was a key factor in the microstructure evolution until the high dose irradiation was reached even in the low Cu content steels though the dislocation loops with much lower density than that of the clusters were observed as matrix damage. The difference in the hardening efficiency due to the difference in the nature of the clusters was small. The irradiation-induced clustering of undersized Si atoms suggested that a clustering driving force other than vacancy-driven diffusion, probably an interstitial mechanism, may become important at higher dose rates

  14. Concomitant formation of different nature clusters and hardening in reactor pressure vessel steels irradiated by heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, K., E-mail: fujiik@inss.co.jp [Institute of Nuclear Safety System, Inc., Mihama 919-1205 (Japan); Fukuya, K. [Institute of Nuclear Safety System, Inc., Mihama 919-1205 (Japan); Hojo, T. [Japan Nuclear Energy Safety Organization, Toranomon, Minato-ku, Tokyo 105-0001 (Japan)

    2013-11-15

    Specimens of A533B steels containing 0.04, 0.09 and 0.21 wt%Cu were irradiated at 290 °C to 3 dpa with 3 MeV Fe ions and subjected to atom probe analyses, transmission electron microscopy observations and hardness measurements. The atom probe analysis results showed that two types of solute clusters were formed: Cu-enriched clusters containing Mn, Ni and Si atoms as irradiation-enhanced solute atom clusters and Mn/Ni/Si-enriched clusters as irradiation-induced solute atom clusters. Both cluster types occurred in the highest Cu-content steel and the ratio of Mn/Ni/Si-enriched clusters to Cu-enriched clusters increased with irradiation doses. It was confirmed that the cluster formation was a key factor in the microstructure evolution until the high dose irradiation was reached even in the low Cu content steels though the dislocation loops with much lower density than that of the clusters were observed as matrix damage. The difference in the hardening efficiency due to the difference in the nature of the clusters was small. The irradiation-induced clustering of undersized Si atoms suggested that a clustering driving force other than vacancy-driven diffusion, probably an interstitial mechanism, may become important at higher dose rates.

  15. Temperature-controlled depth profiling in polymeric materials using cluster secondary ion mass spectrometry (SIMS)

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Christine M. [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States)]. E-mail: christine.mahoney@nist.gov; Fahey, Albert J. [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States); Gillen, Greg [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States); Xu Chang [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States); Batteas, James D. [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States)

    2006-07-30

    Secondary ion mass spectrometry (SIMS) employing an SF{sub 5} {sup +} polyatomic primary ion source was used to depth profile through poly(methylmethacrylate) (PMMA), poly(lactic acid) (PLA) and polystyrene (PS) thin films at a series of temperatures from -125 deg. C to 150 deg. C. It was found that for PMMA, reduced temperature analysis produced depth profiles with increased secondary ion stability and reduced interfacial widths as compared to analysis at ambient temperature. Atomic force microscopy (AFM) images indicated that this improvement in interfacial width may be related to a decrease in sputter-induced topography. Depth profiling at higher temperatures was typically correlated with increased sputter rates. However, the improvements in interfacial widths and overall secondary ion stability were not as prevalent as was observed at low temperature. For PLA, improvements in signal intensities were observed at low temperatures, yet there was no significant change in secondary ion stability, interface widths or sputter rates. High temperatures yielded a significant decrease in secondary ion stability of the resulting profiles. PS films showed rapid degradation of characteristic secondary ion signals under all temperatures examined.

  16. Evaluation of secondary ion yield enhancement from polymer material by using TOF-SIMS equipped with a gold cluster ion source

    Energy Technology Data Exchange (ETDEWEB)

    Aimoto, K. [Department of Applied Physics, Faculty of Engineering, Seikei University, 3-3-1 Kichijioji-Kitamachi, Musashino-shi, Tokyo 180-8633 (Japan)]. E-mail: dm053502@cc.seikei.ac.jp; Aoyagi, S. [Department of Regional Development, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu-cho, Matsue-shi, Shimane 690-8504 (Japan); Kato, N. [Department of Applied Physics, Faculty of Engineering, Seikei University, 3-3-1 Kichijioji-Kitamachi, Musashino-shi, Tokyo 180-8633 (Japan); Iida, N. [ULVAC-PHI, Inc., 370 Enzo, Chigasaki, Kanagawa 253-0084 (Japan); Yamamoto, A. [ULVAC-PHI, Inc., 370 Enzo, Chigasaki, Kanagawa 253-0084 (Japan); Kudo, M. [Department of Applied Physics, Faculty of Engineering, Seikei University, 3-3-1 Kichijioji-Kitamachi, Musashino-shi, Tokyo 180-8633 (Japan)

    2006-07-30

    We investigated the enhancement of the secondary ion intensity in the TOF-SIMS spectra obtained by Au{sup +} and Au{sub 3} {sup +} bombardment in comparison with Ga{sup +} excitation using polymer samples with different molecular weight distributions. Since the polymer samples used in this experiment have a wide molecular weight distribution, the advantages of the gold cluster primary ion source over monoatomic ion could accurately be evaluated. It was observed that the degree of fragmentation decreased by the usage of cluster primary ion beam compared with monoatomic ion beam, which was observed as a shift of the intensity distribution in the spectra. It was also found out that the mass effect of Au{sup +} and Ga{sup +} as monoatomic primary ion, resulted in about 10-60 times of enhancement for both samples with different molecular distributions. On the other hand, the Au{sub 3} {sup +} bombardment caused intensity enhancement about 100-2600 compared with Ga{sup +} bombardment, depending on the mass range of the detected secondary ion species. The cluster primary ion effect of Au{sub 3} {sup +}, compared with Au{sup +}, therefore, was estimated to be about 10-45.

  17. Room temperature diamond-like carbon coatings produced by low energy ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Markwitz, A., E-mail: a.markwitz@gns.cri.nz [Department for Ion Beam Technologies, GNS Science, 30 Gracefield Road, Lower Hutt (New Zealand); The MacDiarmid Institute for Advanced Materials and Nanotechnology (New Zealand); Mohr, B.; Leveneur, J. [Department for Ion Beam Technologies, GNS Science, 30 Gracefield Road, Lower Hutt (New Zealand)

    2014-07-15

    Nanometre-smooth diamond-like carbon coatings (DLC) were produced at room temperature with ion implantation using 6 kV C{sub 3}H{sub y}{sup +} ion beams. Ion beam analysis measurements showed that the coatings contain no heavy Z impurities at the level of 100 ppm, have a homogeneous stoichiometry in depth and a hydrogen concentration of typically 25 at.%. High resolution TEM analysis showed high quality and atomically flat amorphous coatings on wafer silicon. Combined TEM and RBS analysis gave a coating density of 3.25 g cm{sup −3}. Raman spectroscopy was performed to probe for sp{sup 2}/sp{sup 3} bonds in the coatings. The results indicate that low energy ion implantation with 6 kV produces hydrogenated amorphous carbon coatings with a sp{sup 3} content of about 20%. Results highlight the opportunity of developing room temperature DLC coatings with ion beam technology for industrial applications.

  18. Search for and study of the effective mass spectra of nucleon clusters produced in relativistic nucleon collisions

    International Nuclear Information System (INIS)

    Didenko, L.A.; Grishin, V.G.; Kuznetsov, A.A.

    1991-01-01

    The effective mass spectra of nucleon clusters, produced in p, d, He and C collisions with carbon nuclei at P=4.2xA GeV/c are studied. The results obtained show that clusters with proton multiplicity n p =2 and 3 can be interpreted as decay products of nucleon resonances with a width from a few MeV to a few tens MeV. 11 refs.; 6 figs.; 4 tabs

  19. Smoothing of ZnO films by gas cluster ion beam

    International Nuclear Information System (INIS)

    Chen, H.; Liu, S.W.; Wang, X.M.; Iliev, M.N.; Chen, C.L.; Yu, X.K.; Liu, J.R.; Ma, K.; Chu, W.K.

    2005-01-01

    Planarization of wide-band-gap semiconductor ZnO surface is crucial for thin-film device performance. In this study, the rough initial surfaces of ZnO films deposited by r.f. magnetron sputtering on Si substrates were smoothed by gas cluster ion beams. AFM measurements show that the average surface roughness (R a ) of the ZnO films could be reduced considerably from 16.1 nm to 0.9 nm. Raman spectroscopy was used to monitor the structure of both the as-grown and the smoothed ZnO films. Rutherford back-scattering in combination with channeling effect was used to study the damage production induced by the cluster bombardment

  20. X-ray spectroscopic diagnostics of plasma produced by femtosecond laser pulses at interaction with cluster target

    International Nuclear Information System (INIS)

    Skobelev, I.Yu.; Faenov, A.Ya.; Magunov, A.I.

    2002-01-01

    By means of X-ray spectroscopy one determined parameters of plasma produced at interaction of supershort laser pulses with cluster targets. One investigated into the effect of both initial properties of a cluster target and properties of a laser pulse on plasma characteristics. To diagnose plasma one applied a model of production of emitting spectra covering a whole number of free parameters. The conducted experimental investigations show that the investigated model of cluster heating by supershort pulses is the actual physical model, while the applied fitting parameters have a meaning of average values of plasma parameters [ru

  1. Ion Flux Measurements in Electron Beam Produced Plasmas in Atomic and Molecular Gases

    Science.gov (United States)

    Walton, S. G.; Leonhardt, D.; Blackwell, D. D.; Murphy, D. P.; Fernsler, R. F.; Meger, R. A.

    2001-10-01

    In this presentation, mass- and time-resolved measurements of ion fluxes sampled from pulsed, electron beam-generated plasmas will be discussed. Previous works have shown that energetic electron beams are efficient at producing high-density plasmas (10^10-10^12 cm-3) with low electron temperatures (Te < 1.0 eV) over the volume of the beam. Outside the beam, the plasma density and electron temperature vary due, in part, to ion-neutral and electron-ion interactions. In molecular gases, electron-ion recombination plays a significant role while in atomic gases, ion-neutral interactions are important. These interactions also determine the temporal variations in the electron temperature and plasma density when the electron beam is pulsed. Temporally resolved ion flux and energy distributions at a grounded electrode surface located adjacent to pulsed plasmas in pure Ar, N_2, O_2, and their mixtures are discussed. Measurements are presented as a function of operating pressure, mixture ratio, and electron beam-electrode separation. The differences in the results for atomic and molecular gases will also be discussed and related to their respective gas-phase kinetics.

  2. 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

  3. A large-aperture, low-resolution quadrupole separator for producing deposited cluster materials

    CERN Document Server

    Denby, P M

    2000-01-01

    A wide-aperture, low-resolution quadrupole separator for metal clusters is described. Its performance has been evaluated by numerical calculations of the trajectories of clusters. Operating in the frequency range from 5 to 100 KHz allows one to separate clusters in the mass range from 30000 to 300000 AMU and by suitable choice of the AC and DC voltages one can obtain a resolution of 0.15. At this resolution the transmission of clusters from a source is 100% over the selected mass range. By biasing the quadrupole it has been possible to obtain a very sharp cut-off between the transmitted clusters and those outside the selected range. Trajectory calculation for clusters deposited onto a biased 2 cm diameter substrate show that it is possible to keep the deposition energy below 25 eV for 90% of the clusters when the quadrupole is itself biased.

  4. A large-aperture, low-resolution quadrupole separator for producing deposited cluster materials

    Energy Technology Data Exchange (ETDEWEB)

    Denby, P.M.; Eastham, D.A. E-mail: d.a.eastham@dl.ac.uk

    2000-03-01

    A wide-aperture, low-resolution quadrupole separator for metal clusters is described. Its performance has been evaluated by numerical calculations of the trajectories of clusters. Operating in the frequency range from 5 to 100 KHz allows one to separate clusters in the mass range from 30000 to 300000 AMU and by suitable choice of the AC and DC voltages one can obtain a resolution of 0.15. At this resolution the transmission of clusters from a source is 100% over the selected mass range. By biasing the quadrupole it has been possible to obtain a very sharp cut-off between the transmitted clusters and those outside the selected range. Trajectory calculation for clusters deposited onto a biased 2 cm diameter substrate show that it is possible to keep the deposition energy below 25 eV for 90% of the clusters when the quadrupole is itself biased.

  5. A large-aperture, low-resolution quadrupole separator for producing deposited cluster materials

    International Nuclear Information System (INIS)

    Denby, P.M.; Eastham, D.A.

    2000-01-01

    A wide-aperture, low-resolution quadrupole separator for metal clusters is described. Its performance has been evaluated by numerical calculations of the trajectories of clusters. Operating in the frequency range from 5 to 100 KHz allows one to separate clusters in the mass range from 30000 to 300000 AMU and by suitable choice of the AC and DC voltages one can obtain a resolution of 0.15. At this resolution the transmission of clusters from a source is 100% over the selected mass range. By biasing the quadrupole it has been possible to obtain a very sharp cut-off between the transmitted clusters and those outside the selected range. Trajectory calculation for clusters deposited onto a biased 2 cm diameter substrate show that it is possible to keep the deposition energy below 25 eV for 90% of the clusters when the quadrupole is itself biased

  6. Magnetic and Moessbauer-spectroscopic studies of iron-clusters in zeolites. [Reduction of ferrous ions

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, F; Gunsser, W; Knappwost, A [Hamburg Univ. (F.R. Germany). Inst. fuer Physikalische Chemie

    1975-12-01

    Iron clusters have been prepared within zeolite holes by reduction of zeolites containing ferrous ions. The diameter of these particles must therefore be smaller that 13 A. They are superparamagnetic and their Moessbauer spectra show no HFS, even at 4K. The temperature dependence of the magnetic susceptibility of the unreduced zeolites obeys a Curie-Weiss law with p/sub eff/ = 4.45 ..mu..B and THETA = 105K. The Weiss curves of the reduced samples lie distinctly below those of the bulk material.

  7. Study on interaction of swift cluster ion beam with matter and irradiation effect (Joint research)

    International Nuclear Information System (INIS)

    Saito, Yuichi; Shibata, Hiromi

    2010-07-01

    This review covers results of the 'Study of interaction on swift cluster ion beam with matter and irradiation effect' supported by the Interorganization Atomic Energy Research Program from 2006FY to 2008FY. It is composed of a research abstract for each sub-group with viewgraphs which were presented at the group meeting held on March 2009 or 'Meeting of High LET radiation -From fundamental study among physics, chemistry and biology to medical applications-' sponsored by Japan Society of Radiation Chemistry, cosponsored by this research group. (author)

  8. Anomalous intensities of Ne-like ion resonance line in plasma produced by picosecond laser pulse

    International Nuclear Information System (INIS)

    Bryunetkin, B.A.; Skobelev, I.Yu.; Faenov, A.Ya.; Kalashnikov, M.P.; Nikles, P.; Shnyupep, M.

    1995-01-01

    An anomalous structure of intensities of spectral lines of CuXX and GeXXX Ne-like ions emitted by plasma produced by laser pulses of picosecond duration and up to 2x10 18 W/cm 2 flux density is recorded for the first time. It is shown that spectrum maximum of these ions is emitted from a plasma region whose density is significantly above the critical value of the length of heating laser radiation wave. 9 refs.; 3 figs

  9. Ion transport by gating voltage to nanopores produced via metal-assisted chemical etching method

    Science.gov (United States)

    Van Toan, Nguyen; Inomata, Naoki; Toda, Masaya; Ono, Takahito

    2018-05-01

    In this work, we report a simple and low-cost way to create nanopores that can be employed for various applications in nanofluidics. Nano sized Ag particles in the range from 1 to 20 nm are formed on a silicon substrate with a de-wetting method. Then the silicon nanopores with an approximate 15 nm average diameter and 200 μm height are successfully produced by the metal-assisted chemical etching method. In addition, electrically driven ion transport in the nanopores is demonstrated for nanofluidic applications. Ion transport through the nanopores is observed and could be controlled by an application of a gating voltage to the nanopores.

  10. Metastable decay and binding energies of van der Waals cluster ions

    International Nuclear Information System (INIS)

    Ernstberger, B.; Krause, H.; Neusser, H.J.

    1991-01-01

    In this work the appearance potentials for the metastable decay channel of a series of van der Waals dimer ions are presented. Ionization and metastable dissociation is achieved by resonance-enhanced two-photon absorption in a linear reflectron time-of-flight mass spectrometer. From the appearance potentials the binding energy of the neutral dimers is obtained and from the additionally measured ionization potentials binding energies of the dimer cations are achieved. The contribution of charge transfer resonance interaction to the binding in cluster ions is evaluated by investigation of several homo- and heterodimers of aromatic components and the heterodimer benzene/cyclohexane as an example for a dimer consisting of an aromatic and a nonaromatic component. (orig.)

  11. Study of point defect clustering in electron and ion irradiated zirconium alloys

    International Nuclear Information System (INIS)

    Hellio, C.; Boulanger, L.

    1986-09-01

    Dislocation loops created by 500 keV Zr + ions and 1 MeV electrons in zirconium have a/3 type Burgers vectors, and in ion irradiated samples, loops lie preferentially on planes close to (1010). From in-situ observations of loop growth under 1 MeV electron irradiation in zirconium and dilute Zr (Nb,O) alloys, a strong increase of the vacancy migration energy with oxygen concentration was observed, from 0.72 eV for pure zirconium to 1.7 eV for Zr and Zr-1% Nb doped with 1800 ppm weight oxygen, indicating large trapping of vacancies by O single interstitials or clusters

  12. Characteristics and applications of ion streams produced by long-pulse lasers

    International Nuclear Information System (INIS)

    Rohlena, K.; Laska, L.; Jungwirth, K.; Krasa, J.; Krousky, E.; Masek, M.; Pleifer, M.; Ullschmied, J.; Badziak, J.; Parys, P.; Wolowski, J.; Gammino, S.; Torrisi, L.; Boody, F. P.

    2005-01-01

    If a laser plasma generated on a target with a high Z if left to expand it becomes a very efficient source of highly charged ions. Depending on the parameters of the laser driver, ions with charge states from 1+up to more than 50+can be produced, with ion energies ranging from tens of eV up to tens of MeV, with no external acceleration. The ion current density may reach tens of mA/cm''3 at a distance of 1 m from the target. they can be used either for a direct to accelerator injection, for a hybrid ion source based on coupling of a laser with an Electron Cyclotron Resonance Ion Source for easier evaporation and pre-ionisation of the target material and a subsequent charge state enhancement, or for a direct ion implantation. As substrates for the implantation metallic and polymer materials are usually exposed to the laser produced ion streams with an appropriate tuning of the implantation regime to modify their surface properties. Although the interaction of the laser beam with the plasma is a fairly complex process certain fundamental phenomena have been identified based on a careful analysis of the charge-energy spectra of the outgoing ion streams. The most striking feature is a multi peak structure of the energy spectra suggesting the presence of several fast electron groups guiding the plasma expansion and assisting the charge freezing by its acceleration. On the other hand, an inherent asymmetry of the ion spectra with respect to the laser caustic can be interpreted as the onset of self focusing of the heating laser-beam inside the self-created plasma of the developing laser corona (or a pre-pulse plasma either formed by an engineered double pulse or generated spontaneously in the case of an unduly bad contrast of the heating pulse) with a dramatic increase in the power density impinging on the target. Experimental and theoretical arguments are given in support of this notion, which was first advanced by Hora. (Author)

  13. Multiple ionization produced in Yb due to N-,Si- and Ti-ion impact

    International Nuclear Information System (INIS)

    Verma, P.

    2000-01-01

    Heavy ion induced inner shell ionization produces multiple vacancies in the outer shells (M, N etc.) simultaneous to vacancies in the inner-shells (viz. L-shell), which in turn create a very complicated electronic configuration. Three projectiles N 2+,3+ , Si 7+,8+ and Ti 10+,11+ ion beams having a range of 0.3 to 3.5 MeV/u were bombarded on a thin rare earth target of Yb. The recorded L X-ray spectra of Yb have been analyzed in the light of multiple ionization produced due to the heavy ion impact. The outer-shell vacancies acting as spectator vacancies cause a shift in the energy of the various L X-ray diagram lines. A comparison of the shifts in the energies of the various L X-ray transitions of Yb due to the impact of these projectiles, from standard values and that due to proton impact along with the deviation of the intensity ratios from single hole branching ratios, reveal a dependence of multiple ionization on the projectile atomic number (Z) and energy. A further comparison of the degree of multiple ionization produced in Yb, evident by the number of spectator vacancies produced due to the impact of projectiles with 7≤Z≤22 and overlapping MeV/u range lead to explicit conclusions regarding the probability of multiple vacancy production in outer shells simultaneous to a single L-shell vacancy for such projectile target combinations. (orig.)

  14. Impact of aldosterone-producing cell clusters on diagnostic discrepancies in primary aldosteronism

    Science.gov (United States)

    Kometani, Mitsuhiro; Yoneda, Takashi; Aono, Daisuke; Karashima, Shigehiro; Demura, Masashi; Nishimoto, Koshiro; Yamagishi, Masakazu; Takeda, Yoshiyu

    2018-01-01

    Adrenocorticotropic hormone (ACTH) stimulation is recommended in adrenal vein sampling (AVS) for primary aldosteronism (PA) to improve the AVS success rate. However, this method can confound the subtype diagnosis. Gene mutations or pathological characteristics may be related to lateralization by AVS. This study aimed to compare the rate of diagnostic discrepancy by AVS pre- versus post-ACTH stimulation and to investigate the relationship between this discrepancy and findings from immunohistochemical and genetic analyses of PA. We evaluated 195 cases of AVS performed in 2011–2017. All surgical specimens were analyzed genetically and immunohistochemically. Based on the criteria, AVS was successful in 158 patients both pre- and post-ACTH; of these patients, 75 showed diagnostic discrepancies between pre- and post-ACTH. Thus, 19 patients underwent unilateral adrenalectomy, of whom 16 had an aldosterone-producing adenoma (APA) that was positive for CYP11B2 immunostaining. Of them, 10 patients had discordant lateralization between pre- and post-ACTH. In the genetic analysis, the rate of somatic mutations was not significantly different between APA patients with versus without a diagnostic discrepancy. In the immunohistochemical analysis, CYP11B2 levels and the frequency of aldosterone-producing cell clusters (APCCs) in APAs were almost identical between patients with versus without a diagnostic discrepancy. However, both the number and summed area of APCCs in APAs were significantly smaller in patients with concordant results than in those whose diagnosis changed to bilateral PA post-ACTH stimulation. In conclusion, lateralization by AVS was affected by APCCs in the adjacent gland, but not by APA-related factors such as somatic gene mutations. PMID:29899838

  15. Single-column ion chromatography with determination of hydrazoic acid produced in spent nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Ma Guilan; Tan Shuping

    2006-01-01

    The reaction of hydrazine and its derivative with ammonium metavanadate may produce hydrazoic acid (HN 3 ). A single-column ion chromatography is used for the determination of HN 3 after neutralizing the rest acid in the sample with sodium hydroxide. Chromatography separation of HN 3 is carried out on a 25 cm x 0.46 cm (inside diameter) stainless steel column packed with Vydac IC302 ion Chromatography packing. The eluent is 1 mmol/L o-phthalic acid, and the ion is detected by conductivity detector. The detection limit in the presence chromatography is 5 μg/mL, the linear range is from 5 to 201 μg/mL, the linear correlation coefficient is 0.9994, respectively. The analysis accuracy is 2% for standard sample, and the detection limit is 51 μg/mL for HN 3 in the real sample. (authors)

  16. Sn ion energy distributions of ns- and ps-laser produced plasmas

    Science.gov (United States)

    Bayerle, A.; Deuzeman, M. J.; van der Heijden, S.; Kurilovich, D.; de Faria Pinto, T.; Stodolna, A.; Witte, S.; Eikema, K. S. E.; Ubachs, W.; Hoekstra, R.; Versolato, O. O.

    2018-04-01

    Ion energy distributions arising from laser-produced plasmas of Sn are measured over a wide laser parameter space. Planar-solid and liquid-droplet targets are exposed to infrared laser pulses with energy densities between 1 J cm‑2 and 4 kJ cm‑2 and durations spanning 0.5 ps to 6 ns. The measured ion energy distributions are compared to two self-similar solutions of a hydrodynamic approach assuming isothermal expansion of the plasma plume into vacuum. For planar and droplet targets exposed to ps-long pulses, we find good agreement between the experimental results and the self-similar solution of a semi-infinite simple planar plasma configuration with an exponential density profile. The ion energy distributions resulting from solid Sn exposed to ns-pulses agrees with solutions of a limited-mass model that assumes a Gaussian-shaped initial density profile.

  17. The screening of bacillus subtilis strain with high-produced antimicrobial substance using N+ ion implantation

    International Nuclear Information System (INIS)

    Shen Juan; Bie Xiaomei; Lu Zhaoxin; Lu Fengxia; Zhu Xiaoyu

    2006-01-01

    N + ion implantation was used to obtain higher-yield antimicrobial substance. Bacillus subtilis fmbJ was mutated by 25 keV N + ion implantation with the dose of 50 x 2.6 x 10 13 , 80 x 2.6 x 10 13 , 100 x 2.6 x 10 13 , 120 x 2.6 x 10 13 and 150 x 2.6 x 10 13 N + /m 2 . Results showed that the optimal N + ion dose was 50 x 2.6 x 10 13 N + /m 2 , and a strain of high-yield antimicrobials was obtained and named as Bacillus subtilis fmbJ224. Its antimicrobial substance yield was increased by 96% than the initial. The fermentation characteristic of the strain was studied, and the mode of producing antimicrobial substance for the selected strain was arrearage synthesis type. (authors)

  18. Self-modulation and anomalous collective scattering of laser produced intense ion beam in plasmas

    Directory of Open Access Journals (Sweden)

    K. Mima

    2018-05-01

    Full Text Available The collective interaction between intense ion beams and plasmas is studied by simulations and experiments, where an intense proton beam produced by a short pulse laser is injected into a pre-ionized gas. It is found that, depending on its current density, collective effects can significantly alter the propagated ion beam and the stopping power. The quantitative agreement that is found between theories and experiments constitutes the first validation of the collective interaction theory. The effects in the interaction between intense ion beams and background gas plasmas are of importance for the design of laser fusion reactors as well as for beam physics. Keywords: Two stream instabilities, Ultra intense short pulse laser, Proton beam, Wake field, Electron plasma wave, Laser plasma interaction, PACS codes: 52.38.Kd, 29.27.Fh, 52.40.Kh, 52.70.Nc

  19. Neutron measurements in the stray field produced by 158 GeV/c lead ion beams

    International Nuclear Information System (INIS)

    Agosteo, S.; Birattari, C.; Foglio Para, A.; Nava, E.; Silari, M.; Ulrici, L.

    1997-01-01

    This paper discusses measurements carried out at CERN in the stray radiation field produced by 158 GeV/c 208 Pb 82+ ions. The purpose was to test and intercompare the response of several detectors, mainly neutron measuring devices, and to determine the neutron spectral fluence as well as the microdosimetric (absorbed dose and dose equivalent) distributions in different locations around the shielding. Both active instruments and passive dosimeters were employed, including different types of Andersson-Braun rem counters, a tissue equivalent proportional counter, a set of superheated drop detectors, a Bonner sphere system and different types of ion chambers. Activation measurements with 12 C plastic scintillators and with 32 S pellets were also performed to assess the neutron yield of high energy lead ions interacting with a thin gold target. The results are compared with previous measurements and with measurements made during proton runs. (author)

  20. Human Adrenocortical Remodeling Leading to Aldosterone-Producing Cell Cluster Generation

    Directory of Open Access Journals (Sweden)

    Koshiro Nishimoto

    2016-01-01

    Full Text Available Background. The immunohistochemical detection of aldosterone synthase (CYP11B2 and steroid 11β-hydroxylase (CYP11B1 has enabled the identification of aldosterone-producing cell clusters (APCCs in the subcapsular portion of the human adult adrenal cortex. We hypothesized that adrenals have layered zonation in early postnatal stages and are remodeled to possess APCCs over time. Purposes. To investigate changes in human adrenocortical zonation with age. Methods. We retrospectively analyzed adrenal tissues prepared from 33 autopsied patients aged between 0 and 50 years. They were immunostained for CYP11B2 and CYP11B1. The percentage of APCC areas over the whole adrenal area (AA/WAA, % and the number of APCCs (NOA, APCCs/mm2 were calculated by four examiners. Average values were used in statistical analyses. Results. Adrenals under 11 years old had layered zona glomerulosa (ZG and zona fasciculata (ZF without apparent APCCs. Some adrenals had an unstained (CYP11B2/CYP11B1-negative layer between ZG and ZF, resembling the rat undifferentiated cell zone. Average AA/WAA and NOA correlated with age, suggesting that APCC development is associated with aging. Possible APCC-to-APA transitional lesions were incidentally identified in two adult adrenals. Conclusions. The adrenal cortex with layered zonation remodels to possess APCCs over time. APCC generation may be associated with hypertension in adults.

  1. Study of Flux Ratio of C60 to Ar Cluster Ion for Hard DLC Film deposition

    International Nuclear Information System (INIS)

    Miyauchi, K.; Toyoda, N.; Kanda, K.; Matsui, S.; Kitagawa, T.; Yamada, I.

    2003-01-01

    To study the influence of the flux ratio of C60 molecule to Ar cluster ion on (diamond like carbon) DLC film characteristics, DLC films deposited under various flux ratios were characterized with Raman spectrometry and Near Edge X-ray Absorption Fine Structure (NEXAFS). From results of these measurements, hard DLC films were deposited when the flux ratio of C60 to Ar cluster ion was between 0.7 and 4. Furthermore the DLC film with constant sp2 content was obtained in the range of the ratio from 0.7 to 4, which contents are lower values than that of conventional films such as RF plasma. DLC films deposited under the ratio from 1 to 4 had hardness from 40 to 45GPa. It was shown that DLC films with stable properties of low sp2 content and high hardness were formed even when the fluxes were varied from 1 to 4 during deposition. It was indicated that this process was useful in the view of industrial application

  2. ESR investigation of L-α-alanine and sucrose radicals produced by heavy-ion irradiation

    International Nuclear Information System (INIS)

    Nakagawa, K.; Sato, Y.

    2005-01-01

    We investigated sucrose and L-α-alanine radicals produced by heavy (particle) ion irradiation with various LETs (linear energy transfer). The impact of the heavy ions on the samples produced stable free radicals, which were analyzed by ESR (electron spin resonance). Identical spectra were measured after one year. The obtained spectral patterns were the same as those for helium (He), carbon (C), and neon (Ne) ions irradiation. The absorbed dose dependences for the irradiated sucrose and alanine samples were examined. The ESR response has a linear relation with the absorbed dose. The ESR response at 60 Gy was slightly lower than a linear line for sucrose; however, the response showed good linearity for the alanine. In addition, the total spin concentration obtained by heavy-ion irradiation correlated logarithmically with the LET. Qualitative ESR analyse showed that the production of sucrose and alanine radicals depended on both different particle irradiation and the LET under the same dose. Thus, the present ESR results imply that sucrose together with L-α-alanine can be used to monitor LET as well as the number of ionizing particle for the production of stable free radicals. (author)

  3. Plasma diagnostics of the SIMPA Ecr ion source by X-ray spectroscopy, Collisions of H-like Neon ions with Argon clusters

    International Nuclear Information System (INIS)

    Adrouche, N.

    2006-09-01

    The first part of this thesis is devoted to the SIMPA ECR ion source characterization, first, I explored the ion source's capacities on the point of view of extracted currents for three elements, argon, krypton and neon. By analyzing the Bremsstrahlung spectra, I determined the electronic temperature in the plasma and the electronic and ionic densities. In a second time, I recorded high resolution X-spectra of argon and krypton plasma's. By taking into account the principal mechanisms of production of a K hole in the ions inside the plasma, I determined the ionic densities of the high charge states of argon. Lastly, I highlighted a correlation between the ions charge states densities with the intensities of extracted currents. The second part of the thesis is devoted to Ne 9+- argon clusters collisions. First, I presented simple and effective theoretical models allowing to describe the phenomena occurring during a collision, from the point of view of the projectile. I carried out a simulation for a collision of an ion Ne 9+ with an argon cluster of a given size, which has enabled us to know the energy levels populated during the electronic capture and to follow the number of electrons in each projectile shell. Lastly, I presented the first results of a collision between a Ne 9+ beam and argon clusters. These results, have enabled me by using projectile X-ray spectroscopy during the ions-clusters collision, to evidence a strong clustering of targets atoms and to highlight an electronic multi-capture in the projectile ion excited states. (author)

  4. Breeding of tryptophanase-producing Escherichia coli by use of N+ ion beam implantation

    International Nuclear Information System (INIS)

    Pang Min; Yao Jianming

    2009-01-01

    In this paper, the mutation breeding on Escherichia coli producing tryptophanase was studied after low energy N + ion beam implantation. Parameters in the N + ion beam implantation were firstly determined. It has been indicated that a high mutation rate of E.coli could be obtained by N + implantation with 10 keV and 13 x 10 14 N + /cm 2 when glycerin at 15 % concentration used as protector. After continuous mutagenicity a high-yield tryptophanase-producing strain has been screened out and both of its biomass and enzymatic activity are higher than the previous levels respectively. The results of scale-up production show that the biomass could be reach 8.2 g ww ·L -1 and 110 g L-tryptophan could be formed in the volume of 1L enzymatic reaction system. In addition, the characteristics of its stable descend ability and easy operation make it a promising strain for industrialization. (authors)

  5. Ion transport membrane reactor systems and methods for producing synthesis gas

    Science.gov (United States)

    Repasky, John Michael

    2015-05-12

    Embodiments of the present invention provide cost-effective systems and methods for producing a synthesis gas product using a steam reformer system and an ion transport membrane (ITM) reactor having multiple stages, without requiring inter-stage reactant injections. Embodiments of the present invention also provide techniques for compensating for membrane performance degradation and other changes in system operating conditions that negatively affect synthesis gas production.

  6. Ion emission from laser-produced plasmas with two electron temperatures

    International Nuclear Information System (INIS)

    Wickens, L.M.; Allen, J.E.; Rumsby, P.T.

    1978-01-01

    An analytic theory for the expansion of a laser-produced plasma with two electron temperatures is presented. It is shown that from the ion-emission velocity spectrum such relevant parameters as the hot- to -cold-electron density ratio, the absolute hot- and cold-electron temperatures, and a sensitive measure of hot- and cold-electron temperature ratio can be deduced. A comparison with experimental results is presented

  7. ELECTROMAGNETIC THERMAL INSTABILITY WITH MOMENTUM AND ENERGY EXCHANGE BETWEEN ELECTRONS AND IONS IN GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Nekrasov, Anatoly K.

    2011-01-01

    Thermal instability in an electron-ion magnetized plasma, which is relevant in the intragalactic medium of galaxy clusters, solar corona, and other two-component plasma objects, is investigated. We apply the multicomponent plasma approach where the dynamics of all species are considered separately through electric field perturbations. General expressions for the dynamical variables obtained in this paper can be applied over a wide range of astrophysical and laboratory plasmas also containing neutrals and dust grains. We assume that background temperatures of electrons and ions are different and include the energy exchange in thermal equations for electrons and ions along with the collisional momentum exchange in equations of motion. We take into account the dependence of collision frequency on density and temperature perturbations. The cooling-heating functions are taken for both electrons and ions. A condensation mode of thermal instability has been studied in the fast sound speed limit. We derive a new dispersion relation including different electron and ion cooling-heating functions and other effects mentioned above and find its simple solutions for growth rates in limiting cases. We show that the perturbations have an electromagnetic nature and demonstrate the crucial role of the electric field perturbation along the background magnetic field in the fast sound speed limit. We find that at the conditions under consideration, condensation must occur along the magnetic field while the transverse scale sizes can be both larger and smaller than the longitudinal ones. The results obtained can be useful for interpretating observations of dense cold regions in astrophysical objects.

  8. Effects produced in GaAs by MeV ion bombardment

    International Nuclear Information System (INIS)

    Wie, C.R.

    1985-01-01

    The first part of this thesis presents work performed on the ionizing energy beam induced adhesion enhancement of thin (approx.500 A) Au films on GaAs substrates. The ionizing beam, employed in the present thesis, is the MeV ions (i.e., 16 O, 19 F, and 35 Cl), with energies between 1 and 20 MeV. Using the Scratch test for adhesion measurement, and ESCA for chemical analysis of the film substrate interface, the native oxide layer at the interface is shown to play an important role in the adhesion enhancement by the ionizing radiation. A model is discussed that explains the experimental data on the dependence of adhesion enhancement on the energy which was deposited into electronic processes at the interface. The second part of the thesis presents research results on the radiation damage in GaAs crystals produced by MeV ions. Lattice parameter dilatation in the surface layers of the GaAs crystals becomes saturated after a high dose bombardment at room temperature. The strain produced by nuclear collisions is shown to relax partially due to electronic excitation (with a functional dependence on the nuclear and electronic stopping power of bombarding ions. Data on the GaAs and GaP crystals suggest that low temperature recovery stage defects produce major crystal distortion

  9. Cluster analysis of novel isometric strength measures produces a valid and evidence-based classification structure for wheelchair track racing.

    Science.gov (United States)

    Connick, Mark J; Beckman, Emma; Vanlandewijck, Yves; Malone, Laurie A; Blomqvist, Sven; Tweedy, Sean M

    2017-11-25

    The Para athletics wheelchair-racing classification system employs best practice to ensure that classes comprise athletes whose impairments cause a comparable degree of activity limitation. However, decision-making is largely subjective and scientific evidence which reduces this subjectivity is required. To evaluate whether isometric strength tests were valid for the purposes of classifying wheelchair racers and whether cluster analysis of the strength measures produced a valid classification structure. Thirty-two international level, male wheelchair racers from classes T51-54 completed six isometric strength tests evaluating elbow extensors, shoulder flexors, trunk flexors and forearm pronators and two wheelchair performance tests-Top-Speed (0-15 m) and Top-Speed (absolute). Strength tests significantly correlated with wheelchair performance were included in a cluster analysis and the validity of the resulting clusters was assessed. All six strength tests correlated with performance (r=0.54-0.88). Cluster analysis yielded four clusters with reasonable overall structure (mean silhouette coefficient=0.58) and large intercluster strength differences. Six athletes (19%) were allocated to clusters that did not align with their current class. While the mean wheelchair racing performance of the resulting clusters was unequivocally hierarchical, the mean performance of current classes was not, with no difference between current classes T53 and T54. Cluster analysis of isometric strength tests produced classes comprising athletes who experienced a similar degree of activity limitation. The strength tests reported can provide the basis for a new, more transparent, less subjective wheelchair racing classification system, pending replication of these findings in a larger, representative sample. This paper also provides guidance for development of evidence-based systems in other Para sports. © Article author(s) (or their employer(s) unless otherwise stated in the text of

  10. Upgrading traditional technologies in small-scale industrial clusters: producer-driven innovation adoption in Indonesia

    NARCIS (Netherlands)

    Rietveld, Piet; Sandee, Henry

    1997-01-01

    This paper discusses processes of technological change in the tile cluster in the village Karanggeneng in Central Java, Indonesia. A growing number ofproducers in this cluster have switched from traditional kiln to so-called handpress production. We will analyze the processes of innovation adoption

  11. Monte Carlo simulation for neutron yield produced by bombarding thick targets with high energy heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Oh, Joo Hee; Yoon, Moo Hyun; Lee, Hee Seock [POSTECH, Pohang (Korea, Republic of)

    2013-04-15

    One of radiation shielding issues at heavy-ion accelerator facilities is to estimate neutron production by primary heavy ions. A few Monte Carlo transport codes such as FLUKA and PHITS can work with primary heavy ions. Recently IBS/RISP((Rare Isotope Science Project) started to design a high-energy, high-power rare isotope accelerator complex for nuclear physics, medical and material science and applications. There is a lack of experimental and simulated data about the interaction of major beam, {sup 238}U with materials. For the shielding design of the end of first accelerating section section, we calculate a differential neutron yield using the FLUKA code for the interaction of 18.5 MeV/u uranium ion beam with thin carbon stripper of 1.3 μm). The benchmarking studies were also done to prove the yield calculation for 400 MeV/n {sup 131}Xe and other heavy ions. In this study, the benchmarking for Xe-C, Xe-Cu, Xe-Al, Xe-Pb and U-C, other interactions were performed using the FLUKA code. All of results show that the FLUKA can evaluate the heavy ion induced reaction with good uncertainty. For the evaluation of neutron source term, the calculated neutron yields are shown in Fig. 2. The energy of Uranium ion beam is only 18.5 MeV/u, but the energy of produced secondary neutrons was extended over 100 MeV. So the neutron shielding and the damage by those neutrons is expected to be serious. Because of thin stripper, the neutron intensity at forward direction was high. But the the intensity of produced secondary photons was relatively low and mostly the angular property was isotropic. For the detail shielding design of stripper section of RISP rare istope accelerator, the benchmarking study and preliminary evaluation of neutron source term from uranium beam have been carried out using the FLUKA code. This study is also compared with the evaluation results using the PHITS code performed coincidently. Both studies shows that two monte carlo codes can give a good results for

  12. Si clusters/defective graphene composites as Li-ion batteries anode materials: A density functional study

    International Nuclear Information System (INIS)

    Li, Meng; Liu, Yue-Jie; Zhao, Jing-xiang; Wang, Xiao-guang

    2015-01-01

    Highlights: • We study the interaction between Si clusters with pristine and defective graphene. • We find that the binding strength of Si clusters on graphene can be enhanced to different degrees after introducing various defects. • It is found that both graphene and Si cluster in the Si/graphene composites can preserve their Li uptake ability. - Abstract: Recently, the Si/graphene hybrid composites have attracted considerable attention due to their potential application for Li-ion batteries. How to effectively anchor Si clusters to graphene substrates to ensure their stability is an important factor to determine their performance for Li-ion batteries. In the present work, we have performed comprehensive density functional theory (DFT) calculations to investigate the geometric structures, stability, and electronic properties of the deposited Si clusters on defective graphenes as well as their potential applications for Li-ion batteries. The results indicate that the interfacial bonding between these Si clusters with the pristine graphene is quietly weak with a small adsorption energy (<−0.21 eV). Due to the presence of vacancy site, the binding strength of Si clusters on defective graphene is much stronger than that of pristine one, accompanying with a certain amount of charge transfer from Si clusters to graphene substrates. Moreover, the ability of Si/graphene hybrids for Li uptake is studied by calculating the adsorption of Li atoms. We find that both graphenes and Si clusters in the Si/graphene composites preserve their Li uptake ability, indicating that graphenes not only server as buffer materials for accommodating the expansion of Si cluster, but also provide additional intercalation sites for Li

  13. Characteristics of high altitude oxygen ion energization and outflow as observed by Cluster: a statistical study

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, H.; Waara, M.; Arvelius, S.; Yamauchi, M.; Lundin, R. [Inst. of Space Physics, Kiruna (Sweden); Marghitu, O. [Max-Planck-Inst. fuer Extraterrestriche Physik, Garching (Germany); Inst. for Space Sciences, Bucharest (Romania); Bouhram, M. [Max-Planck-Inst. fuer Extraterrestriche Physik, Garching (Germany); CETP-CNRS, Saint-Maur (France); Hobara, Y. [Inst. of Space Physics, Kiruna (Sweden); Univ. of Sheffield, Sheffield (United Kingdom); Reme, H.; Sauvaud, J.A.; Dandouras, I. [Centre d' Etude Spatiale des Rayonnements, Toulouse (France); Balogh, A. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom); Kistler, L.M. [Univ. of New Hampshire, Durham (United States); Klecker, B. [Max-Planck-Inst. fuer Extraterrestriche Physik, Garching (Germany); Carlson, C.W. [Space Science Lab., Univ. of California, Berkeley (United States); Bavassano-Cattaneo, M.B. [Ist. di Fisica dello Spazio Interplanetario, Roma (Italy); Korth, A. [Max-Planck-Inst. fuer Sonnensystemforschung, Katlenburg-Lindau (Germany)

    2006-07-01

    The results of a statistical study of oxygen ion outflow using cluster data obtained at high altitude above the polar cap is reported. Moment data for both hydrogen ions (H{sup +}) and oxygen ions (O{sup +}) from 3 years (2001-2003) of spring orbits (January to May) have been used. The altitudes covered were mainly in the range 5-12 R{sub E} geocentric distance. It was found that O{sup +} is significantly transversely energized at high altitudes, indicated both by high perpendicular temperatures for low magnetic field values as well as by a tendency towards higher perpendicular than parallel temperature distributions for the highest observed temperatures. The O{sup +} parallel bulk velocity increases with altitude in particular for the lowest observed altitude intervals. O{sup +} parallel bulk velocities in excess of 60 km s{sup -1} were found mainly at higher altitudes corresponding to magnetic field strengths of less than 100 nT. For the highest observed parallel bulk velocities of O{sup +} the thermal velocity exceeds the bulk velocity, indicating that the beam-like character of the distribution is lost. The parallel bulk velocity of the H{sup +} and O{sup +} was found to typically be close to the same throughout the observation interval when the H{sup +} bulk velocity was calculated for all pitch-angles. When the H{sup +} bulk velocity was calculated for upward moving particles only the H{sup +} parallel bulk velocity was typically higher than that of O{sup +}. The parallel bulk velocity is close to the same for a wide range of relative abundance of the two ion species, including when the O{sup +} ions dominates. The thermal velocity of O{sup +} was always well below that of H{sup +}. Thus perpendicular energization that is more effective for O{sup +} takes place, but this is not enough to explain the close to similar parallel velocities. Further parallel acceleration must occur. The results presented constrain the models of perpendicular heating and parallel

  14. Characteristics of high altitude oxygen ion energization and outflow as observed by Cluster: a statistical study

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2006-05-01

    Full Text Available The results of a statistical study of oxygen ion outflow using Cluster data obtained at high altitude above the polar cap is reported. Moment data for both hydrogen ions (H+ and oxygen ions (O+ from 3 years (2001-2003 of spring orbits (January to May have been used. The altitudes covered were mainly in the range 5–12 RE geocentric distance. It was found that O+ is significantly transversely energized at high altitudes, indicated both by high perpendicular temperatures for low magnetic field values as well as by a tendency towards higher perpendicular than parallel temperature distributions for the highest observed temperatures. The O+ parallel bulk velocity increases with altitude in particular for the lowest observed altitude intervals. O+ parallel bulk velocities in excess of 60 km s-1 were found mainly at higher altitudes corresponding to magnetic field strengths of less than 100 nT. For the highest observed parallel bulk velocities of O+ the thermal velocity exceeds the bulk velocity, indicating that the beam-like character of the distribution is lost. The parallel bulk velocity of the H+ and O+ was found to typically be close to the same throughout the observation interval when the H+ bulk velocity was calculated for all pitch-angles. When the H+ bulk velocity was calculated for upward moving particles only the H+ parallel bulk velocity was typically higher than that of O+. The parallel bulk velocity is close to the same for a wide range of relative abundance of the two ion species, including when the O+ ions dominates. The thermal velocity of O+ was always well below that of H+. Thus perpendicular energization that is more effective for O+ takes place, but this is not enough to explain the close to similar parallel velocities. Further

  15. Characteristics of high altitude oxygen ion energization and outflow as observed by Cluster: a statistical study

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2006-05-01

    Full Text Available The results of a statistical study of oxygen ion outflow using Cluster data obtained at high altitude above the polar cap is reported. Moment data for both hydrogen ions (H+ and oxygen ions (O+ from 3 years (2001-2003 of spring orbits (January to May have been used. The altitudes covered were mainly in the range 5–12 RE geocentric distance. It was found that O+ is significantly transversely energized at high altitudes, indicated both by high perpendicular temperatures for low magnetic field values as well as by a tendency towards higher perpendicular than parallel temperature distributions for the highest observed temperatures. The O+ parallel bulk velocity increases with altitude in particular for the lowest observed altitude intervals. O+ parallel bulk velocities in excess of 60 km s-1 were found mainly at higher altitudes corresponding to magnetic field strengths of less than 100 nT. For the highest observed parallel bulk velocities of O+ the thermal velocity exceeds the bulk velocity, indicating that the beam-like character of the distribution is lost. The parallel bulk velocity of the H+ and O+ was found to typically be close to the same throughout the observation interval when the H+ bulk velocity was calculated for all pitch-angles. When the H+ bulk velocity was calculated for upward moving particles only the H+ parallel bulk velocity was typically higher than that of O+. The parallel bulk velocity is close to the same for a wide range of relative abundance of the two ion species, including when the O+ ions dominates. The thermal velocity of O+ was always well below that of H+. Thus perpendicular energization that is more effective for O+ takes place, but this is not enough to explain the close to similar parallel velocities. Further parallel acceleration must occur. The results presented constrain the models of perpendicular heating and parallel acceleration. In particular centrifugal acceleration of the outflowing ions, which may

  16. Study of small carbon and semiconductor clusters using negative ion threshold photodetachment spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Caroline Chick [Univ. of California, Berkeley, CA (United States)

    1994-08-01

    The bonding and electronics of several small carbon and semiconductor clusters containing less than ten atoms are probed using negative ion threshold photodetachment (zero electron kinetic energy, or ZEKE) spectroscopy. ZEKE spectroscopy is a particularly advantageous technique for small cluster study, as it combines mass selection with good spectroscopic resolution. The ground and low-lying electronic states of small clusters in general can be accessed by detaching an electron from the ground anion state. The clusters studied using this technique and described in this work are C6-/C6, Sin-/Sin (n = 2, 3, 4), Ge2-/Ge2, In2P-/In2P,InP2-/InP2, and Ga2As-. The total photodetachment cross sections of several other small carbon clusters and the ZEKE spectrum of the I-•CH3I SN2 reaction complex are also presented to illustrate the versatility of the experimental apparatus. Clusters with so few atoms do not exhibit bulk properties. However, each specie exhibits bonding properties that relate to the type of bonding found in the bulk. C6, as has been predicted, exhibits a linear cumulenic structure, where double bonds connect all six carbon atoms. This double bonding reflects how important π bonding is in certain phases of pure carbon (graphite and fullerenes). The symmetric stretch frequencies observed in the C6- spectra, however, are in poor agreement with the calculated values. Also observed as sharp structure in total photodetachment cross section scans was an excited anion state bound by only ~40 cm-1 relative to the detachment continuum. This excited anion state appears to be a valence bound state, possible because of the high electron affinity of C6, and the open shell of the anion.

  17. Raman spectroscopy of few-layer graphene prepared by C2–C6 cluster ion implantation

    International Nuclear Information System (INIS)

    Wang, Z.S.; Zhang, R.; Zhang, Z.D.; Huang, Z.H.; Liu, C.S.; Fu, D.J.; Liu, J.R.

    2013-01-01

    Few-layer graphene has been prepared on 300 nm-thick Ni films by C 2 –C 6 cluster ion implantation at 20 keV/cluster. Raman spectroscopy reveals significant influence of the number of atoms in the cluster, the implantation dose, and thermal treatment on the structure of the graphene layers. In particular, the graphene samples exhibit a sharp G peak at 1584 cm −1 and 2D peaks at 2711–2717 cm −1 . The I G /I 2D ratios higher than 1.70 and I G /I D ratio as high as 1.95 confirm that graphene sheets with low density of defects have been synthesized with much improved quality by ion implantation with larger clusters of C 4 –C 6

  18. Coherent structures at ion scales in fast and slow solar wind: Cluster observations

    Science.gov (United States)

    Perrone, D.; Alexandrova, O.; Zouganelis, Y.; Roberts, O.; Lion, S.; Escoubet, C. P.; Walsh, A. P.; Maksimovic, M.; Lacombe, C.

    2017-12-01

    Spacecraft measurements generally reveal that solar wind electromagnetic fluctuations are in a state of fully-developed turbulence. Turbulence represents a very complex problem in plasmas since cross-scale coupling and kinetic effects are present. Moreover, the intermittency phenomenon, i.e. the manifestation of the non-uniform and inhomogeneous energy transfer and dissipation in a turbulent system, represents a very important aspect of the solar wind turbulent cascade. Here, we study coherent structures responsible for solar wind intermittency around ion characteristic scales. We find that, in fast solar wind, intermittency is due to Alfvén vortex-like structures and current sheets. In slow solar wind, we observe as well compressive structures like magnetic solitons, holes and shocks. By using high-time resolution magnetic field data of multi-point measurements of Cluster spacecraft, we characterize the observed coherent structures in terms of topology and propagation speed. We show that all structures around ion characteristic scales, both in fast and slow solar wind, are characterized by a strong wave-vector anisotropy in the perpendicular direction with respect to the local magnetic field. Moreover, some of them propagate in the plasma rest frame in the direction perpendicular to the local field. Finally, a further analysis on the electron and ion velocity distributions shows a high variability; in particular, close to coherent structures the electron and ion distribution functions appear strongly deformed and far from the thermodynamic equilibrium. Possible interpretations of the observed structures and their role in the heating process of the plasma are also discussed.

  19. Sequencing and Transcriptional Analysis of the Biosynthesis Gene Cluster of Putrescine-Producing Lactococcus lactis ▿ †

    Science.gov (United States)

    Ladero, Victor; Rattray, Fergal P.; Mayo, Baltasar; Martín, María Cruz; Fernández, María; Alvarez, Miguel A.

    2011-01-01

    Lactococcus lactis is a prokaryotic microorganism with great importance as a culture starter and has become the model species among the lactic acid bacteria. The long and safe history of use of L. lactis in dairy fermentations has resulted in the classification of this species as GRAS (General Regarded As Safe) or QPS (Qualified Presumption of Safety). However, our group has identified several strains of L. lactis subsp. lactis and L. lactis subsp. cremoris that are able to produce putrescine from agmatine via the agmatine deiminase (AGDI) pathway. Putrescine is a biogenic amine that confers undesirable flavor characteristics and may even have toxic effects. The AGDI cluster of L. lactis is composed of a putative regulatory gene, aguR, followed by the genes (aguB, aguD, aguA, and aguC) encoding the catabolic enzymes. These genes are transcribed as an operon that is induced in the presence of agmatine. In some strains, an insertion (IS) element interrupts the transcription of the cluster, which results in a non-putrescine-producing phenotype. Based on this knowledge, a PCR-based test was developed in order to differentiate nonproducing L. lactis strains from those with a functional AGDI cluster. The analysis of the AGDI cluster and their flanking regions revealed that the capacity to produce putrescine via the AGDI pathway could be a specific characteristic that was lost during the adaptation to the milk environment by a process of reductive genome evolution. PMID:21803900

  20. Oxidation of nanostructured Ti films produced by low energy cluster beam deposition: An X-ray Photoelectron Spectroscopy characterization

    International Nuclear Information System (INIS)

    Simone, Monica de; Snidero, Elena; Coreno, Marcello; Bongiorno, Gero; Giorgetti, Luca; Amati, Matteo; Cepek, Cinzia

    2012-01-01

    We used in-situ X-ray Photoelectron Spectroscopy (XPS) to study the oxidation process of a cluster-assembled metallic titanium film exposed to molecular oxygen at room temperature. The nanostructured film has been grown on a Si(111) substrate, in ultra high vacuum conditions, by coupling a supersonic cluster beam deposition system with an XPS experimental chamber. Our results show that upon in-situ oxygen exposure Ti 3+ is the first oxidation state observed, followed by Ti 4+ , whereas Ti 2+ is practically absent during the whole process. Our results compare well with the existing literature on Ti films produced using other techniques.

  1. Formation of clusters (ions solvated with products of radiolysis) during irradiation of certain chloralkanes in the condensed phase

    International Nuclear Information System (INIS)

    Sukhov, F.F.; Karatun, A.A.; Slovokhotova, N.A.

    1983-01-01

    Using the infrared spectroscopy method, the radiolysis of the 2-chloropropane and 2-chloro-2-methylpropane was investigated in various phase states and in argon matrix at 15 and 77 K. A conclusion is drawn that the reaction of the radiation dehydrochlorination in the chloralkanes investigated occurs under certain conditions in the vicinity of ions, mostly; as this takes place, unique clusters composed of radiolysis products, i.e. ions solvated with complexes of alkane and hydrogen chloride are being formed. (author)

  2. Spectroscopic study of plasma produced with a heavy ion maxilac beam

    International Nuclear Information System (INIS)

    Belyaev, G.E.; Golubev, A.A.; Sharkov, B.Y.; Mahrt-Olt, K.; Hoffmann, D.H.H.

    1992-01-01

    Spectroscopic study of plasma produced through bombardment of the 1 x 3 mm 2 area on the surface of a solid Mg target with Kr + ions is carried out. Spectral lines of Mg I and Mg II ions were observed in the visible range (200-600 nm). The plasma parameters N e 1.4·10 17 cm -3 and T e = 0.8 eV are calculated from electron impact broadening of the 4f-3d line of MgII and from the ratio of intensities for the 4f-3d and 4s-3p lines of Mg II. The ionic composition of the plasma is determined. The detected X-ray emission is shown to be the characteristic emission of the target. (author)

  3. Private random numbers produced by entangled ions and certified by Bell's theorem

    Science.gov (United States)

    Hayes, David; Matsukevich, Dzmitry; Maunz, Peter; Monroe, Chris; Olmschenk, Steven

    2010-03-01

    It has been shown that entangled particles can be used to generate numbers whose privacy and randomness are guaranteed by the violation of a Bell inequality [1,2]. The authenticity of the bit stream produced is guaranteed when the system used can close the detection loophole and when the entangled particles are non-interacting. We report the use of remotely located trapped ions with near perfect state detection efficiency as a private random number generator. By entangling the ions through photon interference and choosing the measurement settings using a pseudo-random number generator, we measure a CHSH correlation function that is more than seven standard deviations above the classical limit. With a total of 3016 events, we are able to certify the generation of 42 new random numbers with 99% confidence. [1] S. Pironio et al.(submitted to Nature, arXiv:0911.3427) [2] Colbeck, R. PhD Dissertation (2007)

  4. Cement solidification of spent ion exchange resins produced by the nuclear industry

    International Nuclear Information System (INIS)

    Jaouen, C.; Vigreux, B.

    1988-01-01

    Cement solidification technology has been applied to spent ion exchange resins for many years in countries throughout the world (at reactors, research centers and spent fuel reprocessing plants). Changing specifications for storage of radioactive waste have, however, confronted the operators of such facilities with a number of problems. Problems related both to the cement solidification process (water/cement/resin interactions and chemical interactions) and to its utilization (mixing, process control, variable feed composition, etc.) have often led waste producers to prefer other, polymer-based processes, which are very expensive and virtually incompatible with water. This paper discusses research on cement solidification of ion exchange resins since 1983 and the development of application technologies adapted to nuclear service conditions and stringent finished product quality requirements

  5. Irradiation damage in aluminium single crystals produced by 50-keV aluminium and copper ions

    DEFF Research Database (Denmark)

    Henriksen, L.; Johansen, A.; Koch, J.

    1968-01-01

    Aluminium single crystals, thin enough to be examined by electron microscopy, have been irradiated with 50-keV aluminium and copper ions. The irradiation fluxes were in the range 1011–1014 cm−2 s−1 and the doses were from 6 × 1012 to 6 × 1014 cm−2. Irradiation along either a or a direction produces...... rows of dislocation loops all lying parallel to one particular direction. If the aluminium target is quenched from 600 °C and annealed at room temperature prior to irradiation with aluminium ions, the rows of loops are suppressed. The amount of damage observed is considerably less than would...

  6. InGaAsP/InP quantum well buried heterostructure waveguides produced by ion implantation

    International Nuclear Information System (INIS)

    Zucker, J.E.; Jones, K.L.; Tell, B.; Brown-Goebeler, K.; Joyner, C.H.; Miller, B.I.; Young, M.G.

    1992-01-01

    Formation of buried InGaAsP/InP quantum well wave-guides by means of phosphorus ion implantation and thermal annealing during regrowth is demonstrated. Absorption spectra of implanted and unimplanted regions are used to estimate the induced index difference, which is of the order of 1% at 1.55μm. Calculated mode intensities are in good agreement with the observed near field intensity patterns. With this etchless implant technique, we achieve a significant reduction in propagation loss for singlemode pin waveguides relative to etched semi-insulating planar buried heterostructure waveguides fabricated from the same quantum well structure. In addition to reduced scattering loss, buried quantum well waveguides produced by ion implantation are more manufacturable because fewer and less-critical processing steps are involved. (author)

  7. Spectroscopic study of plasma produced with a heavy ion maxilac beam

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, G.E.; Golubev, A.A.; Sharkov, B.Y. (Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj Ehnergii SSSR, Moscow (Russian Federation). Inst. Teoreticheskoj i Ehksperimental' noj Fiziki); Bryunetkin, B.A.; Skobelev, I.Y.; Faenov, A.Y. (Nauchno-Proizvostvennoe Ob' ' edinenie VNIIFTRI, Mendeleevo (Russian Federation)); Mahrt-Olt, K.; Hoffmann, D.H.H. (Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany))

    1992-01-01

    Spectroscopic study of plasma produced through bombardment of the 1 x 3 mm[sup 2] area on the surface of a solid Mg target with Kr[sup +] ions is carried out. Spectral lines of Mg I and Mg II ions were observed in the visible range (200-600 nm). The plasma parameters N[sub e] 1.4[center dot]10[sup 17] cm [sup -3] and T[sub e] = 0.8 eV are calculated from electron impact broadening of the 4f-3d line of MgII and from the ratio of intensities for the 4f-3d and 4s-3p lines of Mg II. The ionic composition of the plasma is determined. The detected X-ray emission is shown to be the characteristic emission of the target. (author).

  8. Controllable fabrication of amorphous Si layer by energetic cluster ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vorlíček, Vladimír; Dejneka, Alexandr; Chvostová, Dagmar; Jäger, Aleš; Vacík, Jiří; Jastrabík, Lubomír; Naramoto, H.; Narumi, K.

    2013-01-01

    Roč. 98, SI (2013), s. 49-55 ISSN 0042-207X R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : energetic cluster s * silicon * surface modification * amorphization * nanostructure * Raman scattering * ion channeling Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 1.426, year: 2013 http://ac.els-cdn.com/S0042207X13001759/1-s2.0-S0042207X13001759-main.pdf?_tid=04e9c946-21dd-11e3-b076-00000aacb361&acdnat=1379672070_859355b2850a09ac74bc8ff413e35dda

  9. Study of Si wafer surfaces irradiated by gas cluster ion beams

    International Nuclear Information System (INIS)

    Isogai, H.; Toyoda, E.; Senda, T.; Izunome, K.; Kashima, K.; Toyoda, N.; Yamada, I.

    2007-01-01

    The surface structures of Si (1 0 0) wafers subjected to gas cluster ion beam (GCIB) irradiation have been analyzed by cross-sectional transmission electron microscopy (XTEM) and atomic force microscopy (AFM). GCIB irradiation is a promising technique for both precise surface etching and planarization of Si wafers. However, it is very important to understand the crystalline structure of Si wafers after GCIB irradiation. An Ar-GCIB used for the physically sputtering of Si atoms and a SF 6 -GCIB used for the chemical etching of the Si surface are also analyzed. The GCIB irradiation increases the surface roughness of the wafers, and amorphous Si layers are formed on the wafer surface. However, when the Si wafers are annealed in hydrogen at a high temperature after the GCIB irradiation, the surface roughness decreases to the same level as that before the irradiation. Moreover, the amorphous Si layers disappear completely

  10. Rice Cluster I, an Important Group of Archaea Producing Methane in Rice Fields

    Science.gov (United States)

    Conrad, R.

    2006-12-01

    Rice fields are an important source for the greenhouse gas methane. Methane is a major degradation product of organic matter in the anoxic soil, is partially oxidized in the rhizosphere and is emitted into the atmosphere through the aerenchyma system of the plants. Anaerobic degradation of organic matter by fermenting bacteria eventually results in the production of acetate and hydrogen, the two major substrates for microbial methanogenesis. The community of methanogenic archaea consists of several major orders or families including hydrogen-utilizing Rice Cluster-I (RC-I). Environmental conditions affect the methanogenic degradation process and the community structure of the methanogenic archaea in soil and rhizosphere. For example, populations of acetoclastic Methanosaetaceae and Methanosarcinaceae are enhanced by low and high acetate concentrations, respectively. Stable isotope probing of 16S rRNA showed that RC-I methanogens are mainly active on rice roots and at low H2 concentrations. Growth and population size is largely consistent with energetic conditions. RC-I methanogens on roots seem to be responsible for methane production from plant photosynthates that account for a major part of the emitted methane. Populations of RC-I methanogens in rice field soil are also enhanced at elevated temperatures (40-50°C). Moderately thermophilic members of RC-I methanogens or other methanogenic families were found to be ubiquitously present in soils from rice fields and river marshes. The genome of a RC-I methanogen was completely sequenced out of an enrichment culture using a metagenome approach. Genes found are consistent with life in the rhizosphere and in temporarily drained, oxic soil. We found that the methanogenic community structure on the rice roots is mainly determined by the respective community structure of the soil, but is in addition affected by the rice cultivar. Rice microcosms in which soil and rice roots are mainly colonized by RC-I methanogens produce

  11. High energy density in matter produced by heavy ion beams. Annual report 1987

    International Nuclear Information System (INIS)

    1988-08-01

    Research activities presented in this annual report were carried out in 1987 in the framework of the government-funded program 'High Energy Density in Matter Produced by Heavy Ion Beams'. It addresses fundamental problems of the generation and investigation of hot dense matter. Its initial motivation and its ultimate goal is the question whether inertial confinement can be achieved by intense heavy ion beams. The new accelerator facility SIS/ESR now under construction at GSI will provide an excellent potential for research in this field. The construction work at the new validity is on schedule. The building construction is near completion and the SIS accelerator will have its first beam at the beginning of next year. First experiments at lower intensity will start in summer 1989 and the full program will run after the cooler and storage ring ESR has got operational. Accordingly, the planning and the preparation of the high energy density experiments at this unique facility was an essential part of the activities last year. In this funding period emphasis was given to the experimental activities at the existing accelerator. In addition to a number of accelerator-oriented and instrumental developments, an experiment on beam-plasma interaction had first exciting results, a significant increase of the stopping power for heavy ions in plasma was measured. Other important activities were the investigation of dielectronic recombination of highly charged ions, spectroscopic investigations aiming at the pumping of short wavelength lasers by heavy ion beams and a crossed beam experiment for the determination of Bi + + Bi + ionization cross sections. As in previous years theoretical work an space-charge dominated beam dynamics as well as on hydrodynamics of dense plasmas, radiation transport and beam plasma interaction was continued, thus providing a basis for the future experiments. (orig.)

  12. Irradiation characteristics of metal-cluster-complex ions containing diverse multi-elements with large mass differences

    International Nuclear Information System (INIS)

    Fujiwara, Yukio; Kondou, Kouji; Teranishi, Yoshikazu; Nonaka, Hidehiko; Saito, Naoaki; Fujimoto, Toshiyuki; Kurokawa, Akira; Ichimura, Shingo; Tomita, Mitsuhiro

    2007-01-01

    Tetrairidium dodecacarbonyl, Ir 4 (CO) 12 , is a metal cluster complex which has a molecular weight of 1104.9. Using a metal-cluster-complex ion source, the interaction between Ir 4 (CO) n + ions (n=0-12) and silicon substrates was studied at a beam energy ranging from 2keV to 10keV at normal incidence. By adjusting Wien-filter voltage, the influence of CO ligands was investigated. Experimental results showed that sputtering yield of silicon bombarded with Ir 4 (CO) n + ions at 10keV decreased with the number of CO ligands. In the case of 2keV, deposition tended to be suppressed by removing CO ligands from the impinging cluster ions. The influence of CO ligands was explained by considering changes in surface properties caused by the irradiation of Ir 4 (CO) n + ions. It was also found that the bombardment with Ir 4 (CO) 7 + ions at 2.5keV caused deposition on silicon target

  13. Radiation damage produced by swift heavy ions in rare earth phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Romanenko, Anton

    2017-02-13

    This work is devoted to the study of radiation damage produced by swift heavy ions in rare earth phosphates, materials that are considered as perspective for radioactive waste storage. Single crystals of rare earth phosphates were exposed to 2.1 GeV gold (Au) and 1.5 GeV xenon (Xe) ions of and analyzed mainly by Raman spectroscopy. All phosphates were found almost completely amorphous after the irradiation by 2.1 GeV Au ions at a fluence of 1 x 10{sup 13} ions/cm{sup 2}. Radiation-induced changes in the Raman spectra include the intensity decrease of all Raman bands accompanied by the appearance of broad humps and a reduction of the pronounced luminescence present in virgin samples. Analyzing the Raman peak intensities as a function of irradiation fluence allowed the calculation of the track radii for 2.1 GeV Au ions in several rare earth phosphates, which appear to be about 5.0 nm for all studied samples. Series of samples were studied to search for a trend of the track radius depending on the rare earth element (REE) cation. Among the monoclinic phosphates both Raman and small-angle X-ray scattering (SAXS) suggest no significant change of the track radius with increasing REE mass. In contrast, within the tetragonal phosphates Raman spectroscopy data suggests a possible slight decreasing trend of the track radius with the increase of REE atomic number. That finding, however, requires further investigation due to the low reliability of the qualitative Raman analysis. Detailed analysis of Raman spectra in HoPO{sub 4} showed the increase of peak width at the initial stage of the irradiation and subsequent decrease to a steady value at higher fluences. This observation suggested the existence of a defect halo around the amorphous tracks in HoPO{sub 4}. Raman peaks were found to initially shift to lower wavenumbers with reversing this trend at the fluence of 5 x 10{sup 11} for NdPO{sub 4} and 1 x 10{sup 12} ions/cm{sup 2} for HoPO{sub 4}. At the next fluence steps

  14. Radiation damage produced by swift heavy ions in rare earth phosphates

    International Nuclear Information System (INIS)

    Romanenko, Anton

    2017-01-01

    This work is devoted to the study of radiation damage produced by swift heavy ions in rare earth phosphates, materials that are considered as perspective for radioactive waste storage. Single crystals of rare earth phosphates were exposed to 2.1 GeV gold (Au) and 1.5 GeV xenon (Xe) ions of and analyzed mainly by Raman spectroscopy. All phosphates were found almost completely amorphous after the irradiation by 2.1 GeV Au ions at a fluence of 1 x 10 13 ions/cm 2 . Radiation-induced changes in the Raman spectra include the intensity decrease of all Raman bands accompanied by the appearance of broad humps and a reduction of the pronounced luminescence present in virgin samples. Analyzing the Raman peak intensities as a function of irradiation fluence allowed the calculation of the track radii for 2.1 GeV Au ions in several rare earth phosphates, which appear to be about 5.0 nm for all studied samples. Series of samples were studied to search for a trend of the track radius depending on the rare earth element (REE) cation. Among the monoclinic phosphates both Raman and small-angle X-ray scattering (SAXS) suggest no significant change of the track radius with increasing REE mass. In contrast, within the tetragonal phosphates Raman spectroscopy data suggests a possible slight decreasing trend of the track radius with the increase of REE atomic number. That finding, however, requires further investigation due to the low reliability of the qualitative Raman analysis. Detailed analysis of Raman spectra in HoPO 4 showed the increase of peak width at the initial stage of the irradiation and subsequent decrease to a steady value at higher fluences. This observation suggested the existence of a defect halo around the amorphous tracks in HoPO 4 . Raman peaks were found to initially shift to lower wavenumbers with reversing this trend at the fluence of 5 x 10 11 for NdPO 4 and 1 x 10 12 ions/cm 2 for HoPO 4 . At the next fluence steps peaks moved in the other direction, passed

  15. SERS analysis of Ag nanostructures produced by ion-beam deposition

    Science.gov (United States)

    Atanasov, P. A.; Nedyalkov, N. N.; Nikov, Ru G.; Grüner, Ch; Rauschenbach, B.; Fukata, N.

    2018-03-01

    This study deals with the development of a novel technique for formation of advanced Ag nanostructures (NSs) to be applied to high-resolution analyses based on surface enhanced Raman scattering (SERS). It has direct bearing on human health and food quality, e.g., monitoring small amount or traces of pollutants or undesirable additives. Three types of nanostructured Ag samples were produced using ion-beam deposition at glancing angle (GLAD) on quartz. All fabricated structures were covered with BI-58 pesticide (dimethoate) or Rhodamine 6G (R6G) for testing their potential for use as substrates for (SERS).

  16. Multi-point observations of Ion Dispersions near the Exterior Cusp with Cluster

    Science.gov (United States)

    Escoubet, C.-Philippe; Grison, Benjamin; Berchem, Jean; Trattner, Kralheinz; Pitout, Frederic; Richard, Robert; Taylor, Matt; Soucek, Jan; Laakso, Harri; Masson, Arnaud; Dunlop, Malcolm; Dandouras, Iannis; Reme, Henri; Fazakerley, Andrew; Daly, Patrick

    2014-05-01

    The exterior cusp is the most external region of the polar magnetosphere in direct contact with the plasma and the magnetic field from the solar wind. Unlike the rest of the magnetopause surface, the exterior cusp is a singular region with small and turbulent magnetic field and where large entry of plasma from solar origin takes place. The main process that injects solar wind plasma into the polar cusp is now generally accepted to be magnetic reconnection. Depending on the IMF direction, this process will take place equatorward (for IMF southward), poleward (for IMF northward) or on the dusk or dawn sides (for IMF azimuthal) of the cusp. We report a Cluster crossing on 5 January 2002 near the exterior cusp on the southern dusk side. The IMF was mainly azimuthal (IMF-By around -5 nT), the solar wind speed lower than usual around 280 km/s and the density around 5 cm-3. The four Cluster spacecraft were still in the "magnetotail" configuration with two perfect tetrahedra of 2000 km around apogee and turning into an elongated configuration near the magnetopause. C4 was the first spacecraft to enter the cusp around 19:52:04 UT, followed by C2 at 19:52:35 UT, C1 at 19:54:24 UT and C3 at 20:13:15 UT. C4 and C1 observed two ion energy dispersions at 20:10 UT and 20:40 UT and C3 at 20:35 UT and 21:15 UT. Using the time of flight technique on the upgoing and downgoing ions in the dispersions, we obtain an altitude of the sources of these ions between 14 and 20 RE. Using Tsyganenko model, these sources are located on the dusk flank, past the terminator. In addition, before entering the cusp, the magnetopause crossing was characterized by a large shear in By and bipolar plasma flows, suggesting that reconnection was taking place near the exterior cusp. We will discuss the extent of the reconnection line along the flank of the magnetopause based on these observations.

  17. Plasma waves produced by an ion beam: observations by the VLF experiment on Porcupine

    International Nuclear Information System (INIS)

    Jones, D.

    1980-01-01

    Results are presented from the VLF electric field experiments flown on Porcupine flights F3 and F4, which also had ejectable xenon ion sources. The xenon ion beam was found to produce plasma instabilities whose frequencies could be linked to the local proton gyrofrequency fsub(cH + ). The main energy in the instabilities lies at approximately 3kHz for events when the Xe + source is close to the rocket, and at approximately 7kHz when the source is farther away. Theory predicts that these frequencies should be the lower-hybrid-resonance and this implies that Xe + is the dominant ion in the first case and that it is the ambient plasma that dominates later. There is no discernable antenna spin-modulation during the Xe events which indicates that the wave k-vectors are not unidirectional. A theory is cited based on the 'setting up' of the proton cyclotron harmonic waves by the Xe + or O + cyclotron harmonic waves. The second Xe + event on both flights exhibited an, as yet, unexplained harmonic structure related to fsub(cH + )/2. (Auth.)

  18. Solar wind dependence of ion parameters in the Earth's magnetospheric region calculated from CLUSTER observations

    Directory of Open Access Journals (Sweden)

    M. H. Denton

    2008-03-01

    Full Text Available Moments calculated from the ion distributions (~0–40 keV measured by the Cluster Ion Spectrometry (CIS instrument are combined with data from the Cluster Flux Gate Magnetometer (FGM instrument and used to characterise the bulk properties of the plasma in the near-Earth magnetosphere over five years (2001–2005. Results are presented in the form of 2-D xy, xz and yz GSM cuts through the magnetosphere using data obtained from the Cluster Science Data System (CSDS and the Cluster Active Archive (CAA. Analysis reveals the distribution of ~0–40 keV ions in the inner magnetosphere is highly ordered and highly responsive to changes in solar wind velocity. Specifically, elevations in temperature are found to occur across the entire nightside plasma sheet region during times of fast solar wind. We demonstrate that the nightside plasma sheet ion temperature at a downtail distance of ~12 to 19 Earth radii increases by a factor of ~2 during periods of fast solar wind (500–1000 km s−1 compared to periods of slow solar wind (100–400 km s−1. The spatial extent of these increases are shown in the xy, xz and yz GSM planes. The results from the study have implications for modelling studies and simulations of solar-wind/magnetosphere coupling, which ultimately rely on in situ observations of the plasma sheet properties for input/boundary conditions.

  19. Fragmentation of pure and hydrated clusters of 5Br-uracil by low energy carbon ions: observation of hydrated fragments

    Czech Academy of Sciences Publication Activity Database

    Castrovilli, M. C.; Markush, P.; Bolognesi, P.; Rousseau, P.; Maclot, S.; Cartoni, A.; Delaunay, R.; Domaracka, A.; Kočišek, Jaroslav; Huber, B. A.; Avaldi, L.

    2017-01-01

    Roč. 19, č. 30 (2017), s. 19807-19814 ISSN 1463-9076 Institutional support: RVO:61388955 Keywords : fragmentation * nano-hydrated 5BrU clusters * low energy carbon ions Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

  20. Molecular dynamics simulations to examine structure, energetics, and evaporation/condensation dynamics in small charged clusters of water or methanol containing a single monatomic ion.

    Science.gov (United States)

    Daub, Christopher D; Cann, Natalie M

    2012-11-01

    We study small clusters of water or methanol containing a single Ca(2+), Na(+), or Cl(-) ion with classical molecular dynamics simulations, using models that incorporate polarizability via the Drude oscillator framework. Evaporation and condensation of solvent from these clusters is examined in two systems, (1) for isolated clusters initially prepared at different temperatures and (2) those with a surrounding inert (Ar) gas of varying temperature. We examine these clusters over a range of sizes, from almost bare ions up to 40 solvent molecules. We report data on the evaporation and condensation of solvent from the clusters and argue that the observed temperature dependence of evaporation in the smallest clusters demonstrates that the presence of heated gas alone cannot, in most cases, solely account for bare ion production in electrospray ionization (ESI), neglecting the key contribution of the electric field. We also present our findings on the structure and energetics of the clusters as a function of size. Our data agree well with the abundant literature on hydrated ion clusters and offer some novel insight into the structure of methanol and ion clusters, especially those with a Cl(-) anion, where we observe the presence of chain-like structures of methanol molecules. Finally, we provide some data on the reparameterizations necessary to simulate ions in methanol using the separately developed Drude oscillator models for methanol and for ions in water.

  1. Laser-produced multi-charged heavy ions as efficient soft x-ray sources

    International Nuclear Information System (INIS)

    Higashiguchi, Takeshi; Suzuki, Yuhei; Kawasaki, Masato

    2016-01-01

    We demonstrate EUV and soft x-ray sources in the 2 to 7 nm spectral region related to the beyond EUV (BEUV) question at 6x nm and a water window source based on laser-produced high-Z plasmas. Resonance emission from multiply charged ions merges to produce intense unresolved transition arrays (UTAs), extending below the carbon K edge (4.37 nm). An outline of a microscope design for single-shot live cell imaging is proposed based on a high-Z plasma UTA source, coupled to x-ray optics. We will discuss the progress and Z-scaling of UTA emission spectra to achieve lab-scale table-top, efficient, high-brightness high-Z plasma EUV-soft x-ray sources for in vivo bio-imaging applications. (author)

  2. Changes in cluster magnetism and suppression of local superconductivity in amorphous FeCrB alloy irradiated by Ar"+ ions

    International Nuclear Information System (INIS)

    Okunev, V.D.; Samoilenko, Z.A.; Szymczak, H.; Szewczyk, A.; Szymczak, R.; Lewandowski, S.J.; Aleshkevych, P.; Malinowski, A.; Gierłowski, P.; Więckowski, J.; Wolny-Marszałek, M.; Jeżabek, M.; Varyukhin, V.N.; Antoshina, I.A.

    2016-01-01

    We show that cluster magnetism in ferromagnetic amorphous Fe_6_7Cr_1_8B_1_5 alloy is related to the presence of large, D=150–250 Å, α-(Fe Cr) clusters responsible for basic changes in cluster magnetism, small, D=30–100 Å, α-(Fe, Cr) and Fe_3B clusters and subcluster atomic α-(Fe, Cr, B) groupings, D=10–20 Å, in disordered intercluster medium. For initial sample and irradiated one (Φ=1.5×10"1"8 ions/cm"2) superconductivity exists in the cluster shells of metallic α-(Fe, Cr) phase where ferromagnetism of iron is counterbalanced by antiferromagnetism of chromium. At Φ=3×10"1"8 ions/cm"2, the internal stresses intensify and the process of iron and chromium phase separation, favorable for mesoscopic superconductivity, changes for inverse one promoting more homogeneous distribution of iron and chromium in the clusters as well as gigantic (twice as much) increase in density of the samples. As a result, in the cluster shells ferromagnetism is restored leading to the increase in magnetization of the sample and suppression of local superconductivity. For initial samples, the temperature dependence of resistivity ρ(T)~T"2 is determined by the electron scattering on quantum defects. In strongly inhomogeneous samples, after irradiation by fluence Φ=1.5×10"1"8 ions/cm"2, the transition to a dependence ρ(T)~T"1"/"2 is caused by the effects of weak localization. In more homogeneous samples, at Φ=3×10"1"8 ions/cm"2, a return to the dependence ρ(T)~T"2 is observed. - Highlights: • The samples at high dose of ion irradiation become more homogeneous. • Gigantic increase in density of the samples (twice as much) is observed. • Ferromagnetism in large Fe–Cr clusters is restored. • Ferromagnetism of Fe–Cr clusters suppresses local superconductivity in them. • The participation of quantum defects in scattering of electrons is returned.

  3. Potential formation in a collisionless plasma produced in an open magnetic field in presence of volume negative ion source

    International Nuclear Information System (INIS)

    Phukan, Ananya; Goswami, K. S.; Bhuyan, P. J.

    2014-01-01

    The electric potential near a wall for a multi-species plasma with volume produced negative ions in presence of axially varying magnetic field is studied following an analytical-numerical approach. A constant negative ion source is assumed throughout the plasma volume, along with finite temperature positive ions and Boltzmann electrons. The particles are assumed to be guided by an open magnetic field that has its maximum at the centre, and field strength decreasing towards the walls. The one dimensional (1D) Poisson equation is derived using an analytical approach, and then solved numerically to study the potential profiles. Effect of (a) negative ion production rate, (b) magnetic field profile, and (c) negative ion temperature on the potential profile has been investigated. A potential peak appears near the wall when the negative ion temperature and density are sufficiently high. Also, the presence of negative ions further decreases the potential in the plasma region for a finite Debye Length (λ D )

  4. Measurements and effects of backstreaming ions produced at bremsstrahlung converter target in Dragon-I linear induction accelerator

    International Nuclear Information System (INIS)

    Yu Haijun; Zhu Jun; Chen Nan; Xie Yutong; Jiang Xiaoguo; Jian Cheng

    2010-01-01

    Positive ions released from x-ray converter target impacted by electron beam of millimeter spot size can be trapped and accelerated in the incident beam's potential well. As the ions move upstream, the beam will be pinched first and then defocused at the target. Four Faraday cups are used to collect backstreaming ions produced at the bremsstrahlung converter target in Dragon-I linear induction accelerator (LIA). Experimental and theoretical results show that the backstreaming positive ions density and velocity are about 10 21 /m 3 and 2-3 mm/μs, respectively. The theoretical and experimental results of electron beam envelope with ions and without ions are also presented. The discussions show that the backstreaming positive ions will not affect the electron beam focusing and envelope radius in Dragon-I LIA.

  5. Mass-produced lonophore-based fluorescent microspheres for trace level determination of lead ions.

    Science.gov (United States)

    Telting-Diaz, Martin; Bakker, Eric

    2002-10-15

    The development and characterization of small, uniform, and mass-produced plasticized PVC-based sensing microspheres in view of rapid trace level analysis of lead ions is reported. Micrometer-sized particles obtained via an automated casting process were rendered selective for lead ions by doping them with highly selective components in a manner analogous to traditional optode sensing films. Single particles that contained the lipophilic ionophore N,N,N',N'-tetradodecyl-3-6-dioxaoctane-1-thio-8-oxodiamide (ETH 5493), the chromoionophore ETH 5418 together with a lipophilized indocarbocyanine derivative as internal reference dye (DiIC18), and lipophilic ion-exchanger sites sodium tetrakis[3,5-bistrifluoromethylphenyl]borate, yielded measurable lead responses at the low nanomolar level in pH buffered solutions. The detection limit for single particles was 3 x 10(-9) M at pH 5.7. The microspheres were fabricated via a reproducible formation of polymer droplets within a flowing aqueous phase followed by collection of spherical particles of approximately 13 microm in size. The particles were immobilized and assayed individually in a microflow cell via fluorescence microscopy. Selectivity patterns found were in agreement with those reported earlier for the lead-selective ligand ETH 5493, and all response functions were fully described by theory. In contrast to optode films that necessitated very long equilibration times and large sample volumes in diluted samples of analyte, particles exhibited extremely enhanced equilibrium response times. Thus, for lead sample concentrations at and above 5 x 10(-8) M, response times were approximately 3 min, whereas at the detection limit, complete equilibrium was recorded after just 15 min, with required sample volumes on the order of 1 mL This new class of microspheres appears to be suitable for rapid and sensitive ion detection at trace levels in environmental and biological applications.

  6. Surface metal standards produced by ion implantation through a removable layer

    International Nuclear Information System (INIS)

    Schueler, B.W.; Granger, C.N.; McCaig, L.; McKinley, J.M.; Metz, J.; Mowat, I.; Reich, D.F.; Smith, S.; Stevie, F.A.; Yang, M.H.

    2003-01-01

    Surface metal concentration standards were produced by ion implantation and investigated for their suitability to calibrate surface metal measurements by secondary ion mass spectrometry (SIMS). Single isotope implants were made through a 100 nm oxide layer on silicon. The implant energies were chosen to place the peak of the implanted species at a depth of 100 nm. Subsequent removal of the oxide layer was used to expose the implant peak and to produce controlled surface metal concentrations. Surface metal concentration measurements by time-of-flight SIMS (TOF-SIMS) with an analysis depth of 1 nm agreed with the expected surface concentrations of the implant standards with a relative mean standard deviation of 20%. Since the TOF-SIMS relative sensitivity factors (RSFs) were originally derived from surface metal measurements of surface contaminated silicon wafers, the agreement implies that the implant standards can be used to measure RSF values. The homogeneity of the surface metal concentration was typically <10%. The dopant dose remaining in silicon after oxide removal was measured using the surface-SIMS protocol. The measured implant dose agreed with the expected dose with a mean relative standard deviation of 25%

  7. NATO Advanced Research Workshop on Methods and Mechanisms for Producing Ions from Large Molecules

    CERN Document Server

    Ens, Werner

    1991-01-01

    A NATO Advanced Research Workshop on Methods and Mechanisms for Producing Ions from Large Molecules was held at Minaki Lodge, Minaki, Ontario, Canada, from 24 to 28 June 1990. The workshop was hosted by the time-of-flight group of the Department of Physics at the University of Manitoba, and was attended by 64 invited participants from around the world. Twenty-nine invited talks were given and 19 papers were presented as posters. Of the 48 contributions, 38 are included in these proceedings. The conference was organized to study the rapidly changing field of mass spectrometry of biomolecules. Particle-induced desorption (especially with MeV particles) has been the most effective method of producing molecular ions from biomolecules. An important part of the workshop was devoted to recent developments in this field, particularly to progress in understanding the fundamentals of the desorption process. In this respect, the meeting was similar to previous conferences in Marburg, FRG (1978); Paris, F (1980); Uppsala...

  8. clusters

    Indian Academy of Sciences (India)

    2017-09-27

    Sep 27, 2017 ... Author for correspondence (zh4403701@126.com). MS received 15 ... lic clusters using density functional theory (DFT)-GGA of the DMOL3 package. ... In the process of geometric optimization, con- vergence thresholds ..... and Postgraduate Research & Practice Innovation Program of. Jiangsu Province ...

  9. clusters

    Indian Academy of Sciences (India)

    environmental as well as technical problems during fuel gas utilization. ... adsorption on some alloys of Pd, namely PdAu, PdAg ... ried out on small neutral and charged Au24,26,27, Cu,28 ... study of Zanti et al.29 on Pdn (n = 1–9) clusters.

  10. Gas cluster ion beam for the characterization of organic materials in submarine basalts as Mars analogs

    International Nuclear Information System (INIS)

    Sano, Naoko; Barlow, Anders J.; Cumpson, Peter J.; Purvis, Graham W. H.; Abbott, Geoffrey D.; Gray, Neil N. D.

    2016-01-01

    The solar system contains large quantities of organic compounds that can form complex molecular structures. The processing of organic compounds by biological systems leads to molecules with distinctive structural characteristics; thus, the detection and characterization of organic materials could lead to a high degree of confidence in the existence of extra-terrestrial life. Given the nature of the surface of most planetary bodies in the solar system, evidence of life is more likely to be found in the subsurface where conditions are more hospitable. Basalt is a common rock throughout the solar system and the primary rock type on Mars and Earth. Basalt is therefore a rock type that subsurface life might exploit and as such a suitable material for the study of methods required to detect and analyze organic material in rock. Telluric basalts from Earth represent an analog for extra-terrestrial rocks where the indigenous organic matter could be analyzed for molecular biosignatures. This study focuses on organic matter in the basalt with the use of surface analysis techniques utilizing Ar gas cluster ion beams (GCIB); time of flight secondary ion mass spectrometry (ToF-SIMS), and x-ray photoelectron spectroscopy (XPS), to characterize organic molecules. Tetramethylammonium hydroxide (TMAH) thermochemolysis was also used to support the data obtained using the surface analysis techniques. The authors demonstrate that organic molecules were found to be heterogeneously distributed within rock textures. A positive correlation was observed to exist between the presence of microtubule textures in the basalt and the organic compounds detected. From the results herein, the authors propose that ToF-SIMS with an Ar GCIB is effective at detecting organic materials in such geological samples, and ToF-SIMS combined with XPS and TMAH thermochemolysis may be a useful approach in the study of extra-terrestrial organic material and life.

  11. Gas cluster ion beam for the characterization of organic materials in submarine basalts as Mars analogs

    Energy Technology Data Exchange (ETDEWEB)

    Sano, Naoko, E-mail: naoko.sano@ncl.ac.uk; Barlow, Anders J.; Cumpson, Peter J. [National EPSRC XPS Users' Service (NEXUS), School of Mechanical and Systems Engineering, Stephenson Building, Newcastle University, Newcastle-upon-Tyne NE1 7RU (United Kingdom); Purvis, Graham W. H.; Abbott, Geoffrey D.; Gray, Neil N. D. [School of Civil Engineering and Geosciences, Devonshire Building, Newcastle University, Newcastle-upon-Tyne NE1 7RU (United Kingdom)

    2016-07-15

    The solar system contains large quantities of organic compounds that can form complex molecular structures. The processing of organic compounds by biological systems leads to molecules with distinctive structural characteristics; thus, the detection and characterization of organic materials could lead to a high degree of confidence in the existence of extra-terrestrial life. Given the nature of the surface of most planetary bodies in the solar system, evidence of life is more likely to be found in the subsurface where conditions are more hospitable. Basalt is a common rock throughout the solar system and the primary rock type on Mars and Earth. Basalt is therefore a rock type that subsurface life might exploit and as such a suitable material for the study of methods required to detect and analyze organic material in rock. Telluric basalts from Earth represent an analog for extra-terrestrial rocks where the indigenous organic matter could be analyzed for molecular biosignatures. This study focuses on organic matter in the basalt with the use of surface analysis techniques utilizing Ar gas cluster ion beams (GCIB); time of flight secondary ion mass spectrometry (ToF-SIMS), and x-ray photoelectron spectroscopy (XPS), to characterize organic molecules. Tetramethylammonium hydroxide (TMAH) thermochemolysis was also used to support the data obtained using the surface analysis techniques. The authors demonstrate that organic molecules were found to be heterogeneously distributed within rock textures. A positive correlation was observed to exist between the presence of microtubule textures in the basalt and the organic compounds detected. From the results herein, the authors propose that ToF-SIMS with an Ar GCIB is effective at detecting organic materials in such geological samples, and ToF-SIMS combined with XPS and TMAH thermochemolysis may be a useful approach in the study of extra-terrestrial organic material and life.

  12. Ion collision-induced chemistry in pure and mixed loosely bound clusters of coronene and C60 molecules.

    Science.gov (United States)

    Domaracka, Alicja; Delaunay, Rudy; Mika, Arkadiusz; Gatchell, Michael; Zettergren, Henning; Cederquist, Henrik; Rousseau, Patrick; Huber, Bernd A

    2018-05-23

    Ionization, fragmentation and molecular growth have been studied in collisions of 22.5 keV He2+- or 3 keV Ar+-projectiles with pure loosely bound clusters of coronene (C24H12) molecules or with loosely bound mixed C60-C24H12 clusters by using mass spectrometry. The heavier and slower Ar+ projectiles induce prompt knockout-fragmentation - C- and/or H-losses - from individual molecules and highly efficient secondary molecular growth reactions before the clusters disintegrate on picosecond timescales. The lighter and faster He2+ projectiles have a higher charge and the main reactions are then ionization by ions that are not penetrating the clusters. This leads mostly to cluster fragmentation without molecular growth. However, here penetrating collisions may also lead to molecular growth but to a much smaller extent than with 3 keV Ar+. Here we present fragmentation and molecular growth mass distributions with 1 mass unit resolution, which reveals that the same numbers of C- and H-atoms often participate in the formation and breaking of covalent bonds inside the clusters. We find that masses close to those with integer numbers of intact coronene molecules, or with integer numbers of both intact coronene and C60 molecules, are formed where often one or several H-atoms are missing or have been added on. We also find that super-hydrogenated coronene is formed inside the clusters.

  13. Inhibitive formation of nanocavities by introduction of Si atoms in Ge nanocrystals produced by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, R. S.; Shang, L.; Liu, X. H.; Zhang, Y. J. [The Cultivation Base for State Key Laboratory, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); Wang, Y. Q., E-mail: yqwang@qdu.edu.cn, E-mail: barba@emt.inrs.ca [The Cultivation Base for State Key Laboratory, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); College of Physics Science, Qingdao University, No. 308 Ningxia Road, Qingdao 266071 (China); Ross, G. G.; Barba, D., E-mail: yqwang@qdu.edu.cn, E-mail: barba@emt.inrs.ca [INRS-Énergie, Matériaux et Télécommunications, 1650 boulevard Lionel-Boulet, Varennes Québec J3X 1S2 (Canada)

    2014-05-28

    Germanium nanocrystals (Ge-nc) were successfully synthesized by co-implantation of Si and Ge ions into a SiO{sub 2} film thermally grown on (100) Si substrate and fused silica (pure SiO{sub 2}), respectively, followed by subsequent annealing at 1150 °C for 1 h. Transmission electron microscopy (TEM) examinations show that nanocavities only exist in the fused silica sample but not in the SiO{sub 2} film on a Si substrate. From the analysis of the high-resolution TEM images and electron energy-loss spectroscopy spectra, it is revealed that the absence of nanocavities in the SiO{sub 2} film/Si substrate is attributed to the presence of Si atoms inside the formed Ge-nc. Because the energy of Si-Ge bonds (301 kJ·mol{sup −1}) are greater than that of Ge-Ge bonds (264 kJ·mol{sup −1}), the introduction of the Si-Ge bonds inside the Ge-nc can inhibit the diffusion of Ge from the Ge-nc during the annealing process. However, for the fused silica sample, no crystalline Si-Ge bonds are detected within the Ge-nc, where strong Ge outdiffusion effects produce a great number of nanocavities. Our results can shed light on the formation mechanism of nanocavities and provide a good way to avoid nanocavities during the process of ion implantation.

  14. High-intensity laser-accelerated ion beam produced from cryogenic micro-jet target

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, M., E-mail: maxence.gauthier@stanford.edu; Kim, J. B.; Curry, C. B.; Gamboa, E. J.; Göde, S.; Propp, A.; Glenzer, S. H. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Aurand, B.; Willi, O. [Heinrich-Heine-University Düsseldorf, Düsseldorf (Germany); Goyon, C.; Hazi, A.; Pak, A.; Ruby, J.; Williams, G. J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Kerr, S. [University of Alberta, Edmonton, Alberta T6G 1R1 (Canada); Ramakrishna, B. [Indian Institute of Technology, Hyderabad (India); Rödel, C. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Friedrich-Schiller-University Jena, Jena (Germany)

    2016-11-15

    We report on the successful operation of a newly developed cryogenic jet target at high intensity laser-irradiation. Using the frequency-doubled Titan short pulse laser system at Jupiter Laser Facility, Lawrence Livermore National Laboratory, we demonstrate the generation of a pure proton beam a with maximum energy of 2 MeV. Furthermore, we record a quasi-monoenergetic peak at 1.1 MeV in the proton spectrum emitted in the laser forward direction suggesting an alternative acceleration mechanism. Using a solid-density mixed hydrogen-deuterium target, we are also able to produce pure proton-deuteron ion beams. With its high purity, limited size, near-critical density, and high-repetition rate capability, this target is promising for future applications.

  15. Design and performance of an UHV beamline to produce low and hyperthermal energy ion beams

    International Nuclear Information System (INIS)

    Adler, D.L.; Cooper, B.H.

    1988-01-01

    We have constructed and tested an UHV beamline to produce beams of alkali metal and noble gas ions over the energy range 0 angular divergence, and nanoamps of current at 25 eV in a 4-mm beam spot with +- 2 0 angular divergence. By applying Liouville's theorem to the beam's emittance and using waist-to-waist transport through the beam optics, the current on the sample is maximized while limiting the spot size and angular divergence. To achieve useful current at the lowest energies, special attention was paid to minimizing space-charge effects. Beam emittances measured at the sample position are consistent with Liouville's theorem. Equations for waist-to-waist transport are derived in the Appendix

  16. Evidence for nano-Si clusters in amorphous SiO anode materials for rechargeable Li-ion batteries

    International Nuclear Information System (INIS)

    Sepehri-Amin, H.; Ohkubo, T.; Kodzuka, M.; Yamamura, H.; Saito, T.; Iba, H.; Hono, K.

    2013-01-01

    Atom probe tomography and high resolution transmission electron microscopy have shown the presence of nano-sized amorphous Si clusters in non-disproportionated amorphous SiO powders are under consideration for anode materials in Li-ion batteries. After Li insertion/extraction, no change was found in the chemistry and structure of the Si clusters. However, Li atoms were found to be trapped at the amorphous SiO phase after Li insertion/extraction, which may be attributed to the large capacity fade after the first charge/discharge cycle

  17. Adsorption and Formation of Small Na Clusters on Pristine and Double-Vacancy Graphene for Anodes of Na-Ion Batteries.

    Science.gov (United States)

    Liang, Zhicong; Fan, Xiaofeng; Zheng, Weitao; Singh, David J

    2017-05-24

    Layered carbon is a likely anode material for Na-ion batteries (NIBs). Graphitic carbon has a low capacity of approximately 35 (mA h)/g due to the formation of NaC 64 . Using first-principles methods including van der Waals interactions, we analyze the adsorption of Na ions and clusters on graphene in the context of anodes. The interaction between Na ions and graphene is found to be weak. Small Na clusters are not stable on the surface of pristine graphene in the electrochemical environment of NIBs. However, we find that Na ions and clusters can be stored effectively on defected graphene that has double vacancies. In addition, the adsorption energy of small Na clusters near a double vacancy is found to decrease with increasing cluster size. With high concentrations of vacancies the capacity of Na on defective graphene is found to be as much as 10-30 times higher than that of graphitic carbon.

  18. Clusters in nuclei

    CERN Document Server

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  19. Structure-volume relationships: singular volume effects produced by cupric ion-globular protein interaction.

    Science.gov (United States)

    Katz, S; Shinaberry, G; Heck, E L; Squire, W

    1980-08-05

    The nature of the volume isotherms produced by the coordination of Cu(II) with ovalbumin and bovine serum albumin differs substantially from the adsorption isotherms produced by these systems. Whereas there was increased binding of Cu(II) associated with a pH increase from pH 5.3 to pH 7.4, the volume isotherms for these systems did not exhibit this type of pH dependence. The volume changes were determined at 30.0 +/- 0.001 degrees C with microdilatometers which could be read to 0.01 muL. The binding isotherms for ovalbumin at pH 5.3 and 7.4 and for bovine serum albumin at pH 5.3 was resolved by a Scatchard plot to yield the appropriate thermodynamic parameters. An algorithm was derived to calculate the distribution of the individual PMi complexes, i.e., PMi-1 + M in equilibrium (Ki) PMi where i equals 1, 2, 3, ..., n moles of cation, M, bound per mole of protein, P, for the above systems. The volume isotherms were then resolved in terms of the constituent delta Vi terms, i.e., the volume change produced by the formation of the individual PMi complexes. These values were verified by an independent graphical differentiation procedure. The coordination of Cu(II) to BSA at pH 7.4 produced a cooperative adsorption isotherm which was not amenable to a Scatchard analysis. The resultant anomalous volume isotherm was resolved into a component related to Cu(II)-site interaction and a negative volume effect attributable to a conformational change induced by complex formation. This structural transition which occurs at physiological pH may constitute a control mechanism for regulating the serum level of Cu(II) and possibly other divalent ions.

  20. Evidence for radical anion formation during liquid secondary ion mass spectrometry analysis of oligonucleotides and synthetic oligomeric analogues: a deconvolution algorithm for molecular ion region clusters.

    Science.gov (United States)

    Laramée, J A; Arbogast, B; Deinzer, M L

    1989-10-01

    It is shown that one-electron reduction is a common process that occurs in negative ion liquid secondary ion mass spectrometry (LSIMS) of oligonucleotides and synthetic oligonucleosides and that this process is in competition with proton loss. Deconvolution of the molecular anion cluster reveals contributions from (M-2H).-, (M-H)-, M.-, and (M + H)-. A model based on these ionic species gives excellent agreement with the experimental data. A correlation between the concentration of species arising via one-electron reduction [M.- and (M + H)-] and the electron affinity of the matrix has been demonstrated. The relative intensity of M.- is mass-dependent; this is rationalized on the basis of base-stacking. Base sequence ion formation is theorized to arise from M.- radical anion among other possible pathways.

  1. Flexible, ionic liquid-based micro-supercapacitor produced by supersonic cluster beam deposition

    International Nuclear Information System (INIS)

    Bettini, L.G.; Piseri, P.; De Giorgio, F.; Arbizzani, C.; Milani, P.; Soavi, F.

    2015-01-01

    Highlights: • We exploited Supersonic Cluster Beam Deposition for the fabrication of a flexible, planar micro-supercapacitor featuring nanostructured carbon electrodes deposited on a plastic Mylar substrate and N-trimethyl-N-propyl-ammonium bis(trifluoromethanesulfonyl) imide (N 1113 TFSI) ionic liquid electrolyte. • The micro-supercapacitor operates at 3 V above RT up to 80 °C with a capacitance density approaching 10 F cm −3 and delivering maximum specific energy and power densities of 10 mWh cm −3 and 8-10 W cm −3 . • The micro-supercapacitor features long cycling stability over 2x10 4 cycle on flat and bent configuration. -- Graphical abstract: Display Omitted -- Abstract: Power generation and storage in electronics require flexible, thin micro-electrochemical energy storage/conversion systems. Micro-supercapacitors (μSCs) with double-layer capacitance carbon electrodes are attracting much attention for their capability of delivering short power pulses with high stability over repeated charge/discharge cycling. Supersonic Cluster Beam Deposition (SCBD) is an effective strategy for the development of nanostructured, binder-free porous carbon electrodes on temperature sensitive substrates including polymers. We exploited SCBD for the development of a flexible, planar μSC featuring nanostructured carbon (ns-C) electrodes deposited on a plastic Mylar substrate and N-trimethyl-N-propyl-ammonium bis(trifluoromethanesulfonyl) imide (N 1113 TFSI) ionic liquid electrolyte. The electrochemical performance at different temperatures of the μSC which operates at 3 V above RT up to 80 °C with a capacitance density approaching 10 F cm −3 and delivering maximum specific energy and power densities of 10 mWh cm −3 and 8-10 W cm −3 with long cycling stability over 2 × 10 4 cycles is here reported and discussed

  2. 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

  3. Reactions of metal ions and their clusters in the gas phase using laser ionization: ion cyclotron resonance spectroscopy

    International Nuclear Information System (INIS)

    Freiser, B.S.

    1981-04-01

    Two subjects are discussed in this report: advances in proposed studies on metal ion chemistry and expansion of laboratory facilities. The development of a combined pulsed laser source-ion cyclotron resonance spectrometer has proven to be a convenient and powerful method for generating metal ions and for studying their subsequent chemistry in the gas phase. The main emphasis of this research has been on the application of metal ions as a selective chemical ionization reagents and progress in this area are discussed. The goal is to identify trends in reactivity i.e. mechanisms useful in interpreting the chemical ionization spectra of unknown compounds and to test for the functional group selectivity of the various metal ions. The feasibility of these goals have been demonstrated in extensive studies on Cu + with esters and ketones, on Fe + with ethers, ketones, and hydrocarbons, and on Ti + with hydrocarbons. In addition, preliminary results on sulfur containing compounds and on a variety of other metallic ions have been obtained. Laboratory facilities were expanded from one ion cyclotron resonance (ICR) spectrometer to two, plus a third instrument the Fourier Transform Ion Cyclotron Resonance (FTICR) spectrometer

  4. Effect of ion irradiation-produced defects on the mobility of dislocations in 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Briceno, M.; Fenske, J. [Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801 (United States); Dadfarnia, M.; Sofronis, P. [Department of Mechanical Science and Engineering, University of Illinois, Urbana, IL 61801 (United States); Robertson, I.M., E-mail: ian.robertson@tcd.ie [Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801 (United States)

    2011-02-01

    The impact of heavy-ion produced defects on the mobility of dislocations, dislocation sources and newly generated dislocations in 304 stainless steel are discovered by performing irradiation and deformation experiments in real time in the transmission electron microscope. Dislocations mobile prior to the irradiation are effectively locked in position by the irradiation, but the irradiation has no discernible impact on the ability of a source to generate dislocations. The motion and mobility of a dislocation is altered by the irradiation. It becomes irregular and jerky and the mobility increases slowly with time as the radiation-produced defects are annihilated locally. Channels created by dislocations ejected from grain boundary dislocation sources were found to have a natural width, as the emission sites within the boundary were spaced close together. Finally, the distribution of dislocations, basically, an inverse dislocation pile-up, within a cleared channel suggests a new mechanism for generating high local levels of stress at grain boundaries. The impact of these observations on the mechanical properties of irradiated materials is discussed briefly.

  5. Effect of ion irradiation-produced defects on the mobility of dislocations in 304 stainless steel

    International Nuclear Information System (INIS)

    Briceno, M.; Fenske, J.; Dadfarnia, M.; Sofronis, P.; Robertson, I.M.

    2011-01-01

    The impact of heavy-ion produced defects on the mobility of dislocations, dislocation sources and newly generated dislocations in 304 stainless steel are discovered by performing irradiation and deformation experiments in real time in the transmission electron microscope. Dislocations mobile prior to the irradiation are effectively locked in position by the irradiation, but the irradiation has no discernible impact on the ability of a source to generate dislocations. The motion and mobility of a dislocation is altered by the irradiation. It becomes irregular and jerky and the mobility increases slowly with time as the radiation-produced defects are annihilated locally. Channels created by dislocations ejected from grain boundary dislocation sources were found to have a natural width, as the emission sites within the boundary were spaced close together. Finally, the distribution of dislocations, basically, an inverse dislocation pile-up, within a cleared channel suggests a new mechanism for generating high local levels of stress at grain boundaries. The impact of these observations on the mechanical properties of irradiated materials is discussed briefly.

  6. Direct measurement of the concentration of metastable ions produced from neutral gas particles using laser-induced fluorescence

    Science.gov (United States)

    Chu, Feng; Skiff, Fred; Berumen, Jorge; Mattingly, Sean; Hood, Ryan

    2017-10-01

    Extensive information can be obtained on wave-particle interactions and wave fields by direct measurement of perturbed ion distribution functions using laser-induced fluorescence (LIF). For practical purposes, LIF is frequently performed on metastables that are produced from neutral gas particles and existing ions in other electronic states. We numerically simulate the ion velocity distribution measurement and wave-detection process using a Lagrangian model for the LIF signal. The results show that under circumstances where the metastable ion population is coming directly from the ionization of neutrals (as opposed to the excitation of ground-state ions), the velocity distribution will only faithfully represent processes which act on the ion dynamics in a time shorter than the metastable lifetime. Therefore, it is important to know the ratio of metastable population coming from neutrals to that from existing ions to correct the LIF measurements of plasma ion temperature and electrostatic waves. In this paper, we experimentally investigate the ratio of these two populations by externally launching an ion acoustic wave and comparing the wave amplitudes that are measured with LIF and a Langmuir probe using a lock-in amplifier. DE-FG02-99ER54543.

  7. Identification of the chelocardin biosynthetic gene cluster from Amycolatopsis sulphurea: a platform for producing novel tetracycline antibiotics.

    Science.gov (United States)

    Lukežič, Tadeja; Lešnik, Urška; Podgoršek, Ajda; Horvat, Jaka; Polak, Tomaž; Šala, Martin; Jenko, Branko; Raspor, Peter; Herron, Paul R; Hunter, Iain S; Petković, Hrvoje

    2013-12-01

    Tetracyclines (TCs) are medically important antibiotics from the polyketide family of natural products. Chelocardin (CHD), produced by Amycolatopsis sulphurea, is a broad-spectrum tetracyclic antibiotic with potent bacteriolytic activity against a number of Gram-positive and Gram-negative multi-resistant pathogens. CHD has an unknown mode of action that is different from TCs. It has some structural features that define it as 'atypical' and, notably, is active against tetracycline-resistant pathogens. Identification and characterization of the chelocardin biosynthetic gene cluster from A. sulphurea revealed 18 putative open reading frames including a type II polyketide synthase. Compared to typical TCs, the chd cluster contains a number of features that relate to its classification as 'atypical': an additional gene for a putative two-component cyclase/aromatase that may be responsible for the different aromatization pattern, a gene for a putative aminotransferase for C-4 with the opposite stereochemistry to TCs and a gene for a putative C-9 methylase that is a unique feature of this biosynthetic cluster within the TCs. Collectively, these enzymes deliver a molecule with different aromatization of ring C that results in an unusual planar structure of the TC backbone. This is a likely contributor to its different mode of action. In addition CHD biosynthesis is primed with acetate, unlike the TCs, which are primed with malonamate, and offers a biosynthetic engineering platform that represents a unique opportunity for efficient generation of novel tetracyclic backbones using combinatorial biosynthesis.

  8. A heteromeric Texas coral snake toxin targets acid-sensing ion channels to produce pain.

    Science.gov (United States)

    Bohlen, Christopher J; Chesler, Alexander T; Sharif-Naeini, Reza; Medzihradszky, Katalin F; Zhou, Sharleen; King, David; Sánchez, Elda E; Burlingame, Alma L; Basbaum, Allan I; Julius, David

    2011-11-16

    Natural products that elicit discomfort or pain represent invaluable tools for probing molecular mechanisms underlying pain sensation. Plant-derived irritants have predominated in this regard, but animal venoms have also evolved to avert predators by targeting neurons and receptors whose activation produces noxious sensations. As such, venoms provide a rich and varied source of small molecule and protein pharmacophores that can be exploited to characterize and manipulate key components of the pain-signalling pathway. With this in mind, here we perform an unbiased in vitro screen to identify snake venoms capable of activating somatosensory neurons. Venom from the Texas coral snake (Micrurus tener tener), whose bite produces intense and unremitting pain, excites a large cohort of sensory neurons. The purified active species (MitTx) consists of a heteromeric complex between Kunitz- and phospholipase-A2-like proteins that together function as a potent, persistent and selective agonist for acid-sensing ion channels (ASICs), showing equal or greater efficacy compared with acidic pH. MitTx is highly selective for the ASIC1 subtype at neutral pH; under more acidic conditions (pH 100-fold) proton-evoked activation of ASIC2a channels. These observations raise the possibility that ASIC channels function as coincidence detectors for extracellular protons and other, as yet unidentified, endogenous factors. Purified MitTx elicits robust pain-related behaviour in mice by activation of ASIC1 channels on capsaicin-sensitive nerve fibres. These findings reveal a mechanism whereby snake venoms produce pain, and highlight an unexpected contribution of ASIC1 channels to nociception. © 2011 Macmillan Publishers Limited. All rights reserved

  9. Size effects in van der Waals clusters studied by spin and angle-resolved electron spectroscopy and multi-coincidence ion imaging

    International Nuclear Information System (INIS)

    Rolles, D; Pesic, Z D; Zhang, H; Bilodeau, R C; Bozek, J D; Berrah, N

    2007-01-01

    We have studied the valence and inner-shell photoionization of free rare-gas clusters by means of angle and spin resolved photoelectron spectroscopy and momentum resolving electron-multi-ion coincidence spectroscopy. The electron measurements probe the evolution of the photoelectron angular distribution and spin polarization parameters as a function of photon energy and cluster size, and reveal a strong cluster size dependence of the photoelectron angular distributions in certain photon energy regions. In contrast, the spin polarization parameter of the cluster photoelectrons is found to be very close to the atomic value for all covered photon energies and cluster sizes. The ion imaging measurements, which probe the fragmentation dynamics of multiply charged van der Waals clusters, also exhibit a pronounced cluster size dependence

  10. Ionization of nitrogen cluster beam

    International Nuclear Information System (INIS)

    Yano, Katsuki; Be, S.H.; Enjoji, Hiroshi; Okamoto, Kosuke

    1975-01-01

    A nitrogen cluster beam (neutral particle intensity of 28.6 mAsub(eq)) is ionized by electron collisions in a Bayard-Alpert gauge type ionizer. The extraction efficiency of about 65% is obtained at an electron current of 10 mA with an energy of 50 eV. The mean cluster size produced at a pressure of 663 Torr and temperature of 77.3 K is 2x10 5 molecules per cluster. By the Coulomb repulsion force, multiply ionized cluster ions are broken up into smaller fragments and the cluster ion size reduces to one-fourth at an electron current of 15 mA. Mean neutral cluster sizes depend strongly on the initial degree of saturation PHI 0 and are 2x10 5 , 7x10 4 and 3x10 4 molecules per cluster at PHI 0 's of 0.87, 0.66 and 0.39, respectively. (auth.)

  11. submitter The effect of acid–base clustering and ions on the growth of atmospheric nano-particles

    CERN Document Server

    Lehtipalo, Katrianne; Kontkanen, Jenni; Schobesberger, Siegfried; Jokinen, Tuija; Sarnela, Nina; Kürten, Andreas; Ehrhart, Sebastian; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Sipilä, Mikko; Yli-Juuti, Taina; Duplissy, Jonathan; Adamov, Alexey; Ahlm, Lars; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; Dommen, Josef; Downard, Andrew J; Dunne, Eimear M; Flagan, Richard C; Guida, Roberto; Hakala, Jani; Hansel, Armin; Jud, Werner; Kangasluoma, Juha; Kerminen, Veli-Matti; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Kupc, Agnieszka; Kupiainen-Määttä, Oona; Laaksonen, Ari; Lawler, Michael J; Leiminger, Markus; Mathot, Serge; Olenius, Tinja; Ortega, Ismael K; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud; Rissanen, Matti P; Ruuskanen, Taina; Santos, Filipe D; Schallhart, Simon; Schnitzhofer, Ralf; Simon, Mario; Smith, James N; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Tomé, António; Vaattovaara, Petri; Vehkamäki, Hanna; Vrtala, Aron E; Wagner, Paul E; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Virtanen, Annele; Donahue, Neil M; Carslaw, Kenneth S; Baltensperger, Urs; Riipinen, Ilona; Curtius, Joachim; Worsnop, Douglas R; Kulmala, Markku

    2016-01-01

    The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at sub-3 nm sizes with different atmospherically relevant concentrations of sulphuric acid, water, ammonia and dimethylamine. We find that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process, leading to enhanced growth rates. The availability of compounds capable of stabilizing sulphuric acid clusters governs the magnitude of these effects and thus the exact growth mechanism. We bring these observations into a ...

  12. Tribological coatings for complex mechanical elements produced by supersonic cluster beam deposition of metal dichalcogenide nanoparticles

    Science.gov (United States)

    Piazzoni, C.; Buttery, M.; Hampson, M. R.; Roberts, E. W.; Ducati, C.; Lenardi, C.; Cavaliere, F.; Piseri, P.; Milani, P.

    2015-07-01

    Fullerene-like MoS2 and WS2 nanoparticles can be used as building blocks for the fabrication of fluid and solid lubricants. Metal dichalcogenide films have a very low friction coefficient in vacuum, therefore they have mostly been used as solid lubricants in space and vacuum applications. Unfortunately, their use is significantly hampered by the fact that in the presence of humidity, oxygen and moisture, the low-friction properties of these materials rapidly degrade due to oxidation. The use of closed-cage MoS2 and WS2 nanoparticles may eliminate this problem, although the fabrication of lubricant thin films starting from dichalcogenide nanoparticles is, to date, a difficult task. Here we demonstrate the use of supersonic cluster beam deposition for the coating of complex mechanical elements (angular contact ball bearings) with nanostructured MoS2 and WS2 thin films. We report structural and tribological characterization of the coatings in view of the optimization of tribological performances for aerospace applications.

  13. Absolute single-ion solvation free energy scale in methanol determined by the lithium cluster-continuum approach.

    Science.gov (United States)

    Pliego, Josefredo R; Miguel, Elizabeth L M

    2013-05-02

    Absolute solvation free energy of the lithium cation in methanol was calculated by the cluster-continuum quasichemical theory of solvation. Clusters with up to five methanol molecules were investigated using X3LYP, MP2, and MP4 methods with DZVP, 6-311+G(2df,2p), TZVPP+diff, and QZVPP+diff basis sets and including the cluster solvation through the PCM and SMD continuum models. Our calculations have determined a value of -118.1 kcal mol(-1) for the solvation free energy of the lithium, in close agreement with a value of -116.6 kcal mol(-1) consistent with the TATB assumption. Using data of solvation and transfer free energy of a pair of ions, electrode potentials and pKa, we have obtained the solvation free energy of 25 ions in methanol. Our analysis leads to a value of -253.6 kcal mol(-1) for the solvation free energy of the proton, which can be compared with the value of -263.5 kcal mol(-1) obtained by Kelly et al. using the cluster pair approximation. Considering that this difference is due to the methanol surface potential, we have estimated that it corresponds to -0.429 V.

  14. Reactivity Control of Rhodium Cluster Ions by Alloying with Tantalum Atoms.

    Science.gov (United States)

    Mafuné, Fumitaka; Tawaraya, Yuki; Kudoh, Satoshi

    2016-02-18

    Gas phase, bielement rhodium and tantalum clusters, RhnTam(+) (n + m = 6), were prepared by the double laser ablation of Rh and Ta rods in He carrier gas. The clusters were introduced into a reaction gas cell filled with nitric oxide (NO) diluted with He and were subjected to collisions with NO and He at room temperature. The product species were observed by mass spectrometry, demonstrating that the NO molecules were sequentially adsorbed on the RhnTam(+) clusters to form RhnTam(+)NxOx (x = 1, 2, 3, ...) species. In addition, oxide clusters, RhnTam(+)O2, were also observed, suggesting that the NO molecules were dissociatively adsorbed on the cluster, the N atoms migrated on the surface to form N2, and the N2 molecules were released from RhnTam(+)N2O2. The reactivity, leading to oxide formation, was composition dependent: oxide clusters were dominantly formed for the bielement clusters containing both Rh and Ta atoms, whereas such clusters were hardly formed for the single-element Rhn(+) and Tam(+) clusters. DFT calculations indicated that the Ta atoms induce dissociation of NO on the clusters by lowering the dissociation energy, whereas the Rh atoms enable release of N2 by lowering the binding energy of the N atoms on the clusters.

  15. Biodegradable radioactive implants for glaucoma filtering surgery produced by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Assmann, W. [Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, 85748 Garching (Germany)]. E-mail: walter.assmann@lmu.de; Schubert, M. [Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, 85748 Garching (Germany); Held, A. [Augenklinik, Technische Universitaet Muenchen, 81675 Munich (Germany); Pichler, A. [Augenklinik, Technische Universitaet Muenchen, 81675 Muenchen (Germany); Chill, A. [Zentralinstitut fuer Medizintechnik, Technische Universitaet Muenchen, 85748 Garching (Germany); Kiermaier, S. [Zentralinstitut fuer Medizintechnik, Technische Universitaet Muenchen, 85748 Garching (Germany); Schloesser, K. [Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany); Busch, H. [NTTF GmbH, 53619 Rheinbreitbach (Germany); Schenk, K. [NTTF GmbH, 53619 Rheinbreitbach (Germany); Streufert, D. [Acri.Tec GmbH, 16761 Hennigsdorf (Germany); Lanzl, I. [Augenklinik, Technische Universitaet Muenchen, 81675 Munich (Germany)

    2007-04-15

    A biodegradable, {beta}-emitting implant has been developed and successfully tested which prevents fresh intraocular pressure increase after glaucoma filtering surgery. Ion implantation has been used to load the polymeric implants with the {beta}-emitter {sup 32}P. The influence of ion implantation and gamma sterilisation on degradation and {sup 32}P-fixation behavior has been studied by ion beam and chemical analysis. Irradiation effects due to the applied ion fluence (10{sup 15} ions/cm{sup 2}) and gamma dose (25 kGy) are found to be tolerable.

  16. Cluster-assistant generation of multiply charged atomic ions in nanosecond laser ionization of seeded methyl iodide beam

    International Nuclear Information System (INIS)

    Luo Xiaolin; Niu Dongmei; Kong Xianglei; Wen Lihua; Liang Feng; Pei Kemei; Wang Bin; Li Haiyang

    2005-01-01

    The photoionization of methyl iodide beam seeded in argon and helium is studied by time-of-flight mass spectrometry using a 25 ns, 532 nm Nd-YAG laser with intensities in the range of 2 x 10 10 -2 x 10 11 W/cm 2 . Multiply charged ions of I q+ (q = 2-3) and C 2+ with tens of eV kinetic energies have been observed when laser interacts with the middle part of the pulsed molecular beam, whose peak profiles are independent on the laser polarization directions. Strong evidences show that these ions are coming from the Coulomb explosion of multiply charged CH 3 I clusters, and laser induced inverse bremsstrahlung absorption of caged electrons plays a key role in the formation of multiply charged ions

  17. High yield antibiotic producing mutants of Streptomyces erythreus induced by low energy ion implantation

    Science.gov (United States)

    Yu, Chen; Zhixin, Lin; Zuyao, Zou; Feng, Zhang; Duo, Liu; Xianghuai, Liu; Jianzhong, Tang; Weimin, Zhu; Bo, Huang

    1998-05-01

    Conidia of Streptomyces erythreus, an industrial microbe, were implanted by nitrogen ions with energy of 40-60 keV and fluence from 1 × 10 11 to 5 × 10 14 ions/cm 2. The logarithm value of survival fraction had good linear relationship with the logarithm value of fluence. Some mutants with a high yield of erythromycin were induced by ion implantation. The yield increment was correlated with the implantation fluence. Compared with the mutation results induced by ultraviolet rays, mutation effects of ion implantation were obvious having higher increasing erythromycin potency and wider mutation spectrum. The spores of Bacillus subtilis were implanted by arsenic ions with energy of 100 keV. The distribution of implanted ions was measured by Rutherford Backscattering Spectrometry (RBS) and calculated in theory. The mechanism of mutation induced by ion implantation was discussed.

  18. Cluster observations of the high-latitude magnetopause and cusp: initial results from the CIS ion instruments

    Directory of Open Access Journals (Sweden)

    J. M. Bosqued

    2001-09-01

    Full Text Available Launched on an elliptical high inclination orbit (apogee: 19.6 RE since January 2001 the Cluster satellites have been conducting the first detailed three-dimensional studies of the high-latitude dayside magnetosphere, including the exterior cusp, neighbouring boundary layers and magnetopause regions. Cluster satellites carry the CIS ion spectrometers that provide high-precision, 3D distributions of low-energy (<35 keV/e ions every 4 s. This paper presents the first two observations of the cusp and/or magnetopause behaviour made under different interplanetary magnetic field (IMF conditions. Flow directions, 3D distribution functions, density profiles and ion composition profiles are analyzed to demonstrate the high variability of high-latitude regions. In the first crossing analyzed (26 January 2001, dusk side, IMF-BZ < 0, multiple, isolated boundary layer, magnetopause and magnetosheath encounters clearly occurred on a quasi-steady basis for ~ 2 hours. CIS ion instruments show systematic accelerated flows in the current layer and adjacent boundary layers on the Earthward side of the magnetopause. Multi-point analysis of the magnetopause, combining magnetic and plasma data from the four Cluster spacecraft, demonstrates that oscillatory outward-inward motions occur with a normal speed of the order of ± 40 km/s; the thickness of the high-latitude current layer is evaluated to be of the order of 900–1000 km. Alfvénic accelerated flows and D-shaped distributions are convincing signatures of a magnetic reconnection occurring equatorward of the Cluster satellites. Moreover, the internal magnetic and plasma structure of a flux transfer event (FTE is analyzed in detail; its size along the magnetopause surface is ~ 12 000 km and it convects with a velocity of ~ 200 km/s. The second event analyzed (2 February 2001 corresponds to the first Cluster pass within the cusp when the IMF-BZ component was northward directed. The analysis of relevant CIS plasma

  19. Cluster observations of the high-latitude magnetopause and cusp: initial results from the CIS ion instruments

    Directory of Open Access Journals (Sweden)

    J. M. Bosqued

    Full Text Available Launched on an elliptical high inclination orbit (apogee: 19.6 RE since January 2001 the Cluster satellites have been conducting the first detailed three-dimensional studies of the high-latitude dayside magnetosphere, including the exterior cusp, neighbouring boundary layers and magnetopause regions. Cluster satellites carry the CIS ion spectrometers that provide high-precision, 3D distributions of low-energy (<35 keV/e ions every 4 s. This paper presents the first two observations of the cusp and/or magnetopause behaviour made under different interplanetary magnetic field (IMF conditions. Flow directions, 3D distribution functions, density profiles and ion composition profiles are analyzed to demonstrate the high variability of high-latitude regions. In the first crossing analyzed (26 January 2001, dusk side, IMF-BZ < 0, multiple, isolated boundary layer, magnetopause and magnetosheath encounters clearly occurred on a quasi-steady basis for ~ 2 hours. CIS ion instruments show systematic accelerated flows in the current layer and adjacent boundary layers on the Earthward side of the magnetopause. Multi-point analysis of the magnetopause, combining magnetic and plasma data from the four Cluster spacecraft, demonstrates that oscillatory outward-inward motions occur with a normal speed of the order of ± 40 km/s; the thickness of the high-latitude current layer is evaluated to be of the order of 900–1000 km. Alfvénic accelerated flows and D-shaped distributions are convincing signatures of a magnetic reconnection occurring equatorward of the Cluster satellites. Moreover, the internal magnetic and plasma structure of a flux transfer event (FTE is analyzed in detail; its size along the magnetopause surface is ~ 12 000 km and it convects with a velocity of ~ 200 km/s. The second event analyzed (2 February 2001 corresponds to the first Cluster pass within the cusp when the IMF-BZ component was northward directed. The analysis of

  20. Electron induced formation and stability of molecular and cluster ions in gas phase and superfluid helium nanodroplets

    International Nuclear Information System (INIS)

    Aleem, M. A.

    2010-01-01

    The present PhD thesis represents a broad range study of electron induced formation and stability of positive and negative ions in gas phase and superfluid helium nanodroplets. The molecules studied are of industrial, environmental, plasma and biological relevance. The knowledge obtained from the study provides new insight for the proper understanding and control on energetics and dynamics of the reactions involved in the formation and fragmentation processes of the studied molecules and clusters. The experiments are accomplished and investigated using mass spectrometric techniques for the formation of molecular and cluster ions using different mass spectrometers available in our laboratory. One part of the work is focused on electron-induced reactions of the molecules in gas phase. Especially focus is laid to electron attachment to the isomers of mononitrotolouene used as an additive to explosives. The fragile nature and high internal energy of these molecules has lead to extensive fragmentation following the ionisation process. Dissociative electron attachment to the three different isomers has shown different resonances and therefore this process can be utilized to explicitly distinguish these isomers. Anion efficiency curves of the isomers have been studied using effusive molecular beam source in combination with a hemispherical electron monochromator as well as a Nier-type ion source attached to a sector field mass spectrometer. The outcome of the experiment is a reliable and effective detection method highly desirable for environmental and security reasons. Secondly, dissociative electron ionization of acetylene and propene is studied and their data is directly related to the plasma modelling for plasma fusion and processing reactors. Temperature effects for dissociative electron attachment to halo-hydrocarbons are also measured using a trochoidal electron monochromator. The second part of the work is concerned with the investigation of electron

  1. Modifications of poly (vinilydene fluoride) under electronic excitations produced by charged particles (heavy ions and electrons)

    International Nuclear Information System (INIS)

    Fina, A.

    1990-04-01

    Some of the physico-chemical properties of organic solids like conductivity or permeation can be improved by irradiation. The aim of this work is to characterize modifications induced in poly (vinylidene fluoride) films (PVDF) by charged particles (ions and electrons), with electronic stopping power, for doses ranging from zero to twenty G-Grays. Influence of dose, density of electronic excitations, and flux (in particles per square centimeter), and the nature of defects induced by the beam, were studied with two methods: X-ray Photoelectron Spectroscopy (or XPS) for surface analysis, and electron Spin Resonance (or ESR) to probe the bulk of the film. Three ranges of doses are revealed in view of experimental results. At lower doses, PVDF undergoes deshydrofluorination induced by desorption; it is a low modifications regime. For intermediate range doses, conjugated carbon backbones of polyene compounds are produced. At higher doses, intermolecular interactions between the resulting fragments give a crosslinked network. For the upper limit of doses used, bond breaking results in a non reversible degradation of PVDF. In this last situation, direct atomic displacement of target atoms, is not negligible [fr

  2. Electrochemical performance of arc-produced carbon nanotubes as anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Yang, Shubin; Song, Huaihe; Chen, Xiaohong; Okotrub, A.V.; Bulusheva, L.G.

    2007-01-01

    The effects of etching process on the morphology, structure and electrochemical performance of arc-produced multiwalled carbon nanotubes (CNTs) as anode material for lithium-ion batteries were systematically investigated by TEM and a variety of electrochemical testing techniques. It was found that the etched CNTs exhibited four times higher reversible capacity than that of raw CNTs, and possessed excellent cyclability with almost 100% capacity retention after 30 cycles. The kinetic properties of three kinds of CNTs electrodes involving the pristine (CNTs-1), etched (CNTs-2) as well as etch-carbonized samples (CNTs-3) were characterized via ac impedance measurement. It was indicated that, after 30 cycles the exchange current density i 0 of etched CNTs ((7.6-7.8) x 10 -3 A cm -2 ) was higher than that of the raw CNTs (5.9 x 10 -3 A cm -2 ), suggesting the electrochemical activity of CNTs was enhanced by the etching treatment. The storage characteristics of the CNTs electrodes at room temperature and 50 o C were particularly compared. It was found that the film resistance on CNTs electrode generally tended to become large with the elongation of storage time, especially storage at high temperature. In comparison with CNTs-1 and CNTs-3, CNTs-2 exhibited more distinctly increase of film resistance, which is related with the surface properties

  3. Hot magnetospheric O+ and cold ion behavior in magnetopause reconnection: Cluster observations

    Science.gov (United States)

    Wang, S.; Kistler, L. M.; Mouikis, C. G.; Liu, Y.; Genestreti, K. J.

    2014-12-01

    In reconnection, the presence of heavy ions like O+ increases the ion mass density reducing the fluid's Alfvén speed. In addition, it may modify the reconnection structure, which can also change the reconnection rate. However, because O+ ions have a larger Larmor radii than H+ ions at the same velocity, they may not be fully entrained in the reconnection flow and may have kinetic effects other than just increasing the mass density. In this study, for the first time, the ion velocity distribution functions of H+ and O+ from one magnetopause reconnection event with a strong guide field are analyzed to determine in detail the behavior of the different ion populations. We show that the hot magnetospheric O+ ions, along with the hot magnetospheric H+ ions almost fully participate in the reconnection exhaust flows. Finite Larmor radius effects are also apparent and control how far the ions extend on the magnetosheath side. Ion signatures consistent with heating after being picked up in the reconnection exhaust flow are observed in the H+ and O+ distribution functions. The dynamics of the cold magnetospheric ions depends on where they enter the reconnection region. If they enter the reconnection region at the downstream separatrix, they will be taken away by the magnetic field in an adiabatic way as analyzed by Drake et al. (2009a); if they enter close to the diffusion region, they behave as pick-up ions.

  4. Features of produced flows of multiply charged ions at interaction of laser radiation with single-component solids

    International Nuclear Information System (INIS)

    Bedilov, M.R.; Bedilov, R.M.; Beysembaeva, H.B.; Sabitov, M.S.; Kamalova, J.O.

    2006-01-01

    Full text: The results of study features of formation multiply charged ions spectra of single-component solids depending on a target element composition in an interval of laser radiation power density q = 10 7 / 10 12 W/cm 2 with using of the laser multiply charged mass spectrometer [1] are given in this work. As single-component targets are used Be, B, C, Al, Ti, Fe, Co, Ni, Cu, Ag, Ta, W, Pt, Au as tablets in diameter of 10 mm and thickness of 3-5 mm. Analysis of the obtained mass-charge and energy spectra of multiply charged ions depending on a target element composition has allowed us to find features of formation spectra and escape multiply charged ions of a single-component targets. These features consist in characteristic changes: a threshold produced of ions; formation of mass-charge and energy spectra of multiply charged ions; nonlinear dependence of maximal charge number (Z max ) of ions from power density (q) of the laser; etc. Experimentally it was found that, with target atomic weight increase, threshold power of ions occurrence, nonlinearity ionization target structure, and intensity of ions, and energy spectra of ions increase. Let's note that, in case of targets Be, B, C, Al by laser radiation it is completely ionized and multiply charged ions and nuclei Be 4+ , B 5+ , C 6+ , Al 13+ are formed. The major level of ionization is attained in case of targets from Ti (Ti 17+ ) and Co (Co 18+ ). It is peculiar that structure formation and escape of multiply charged ion flows with Z max and nuclei depending on target element composition corresponds to various maximal values q of the laser. Increase of the maximal charge number of ions (atoms) observed with increase q of the laser for all investigated targets has nonlinear dependence in various levels that is especially shown beginning from q≥ 10 11 W/cm 2 . It is found that depending on target element composition multiply charged ions have a wide energy range with a maximum of allocation. With increase

  5. Ab initio dynamics and photoionization mass spectrometry reveal ion-molecule pathways from ionized acetylene clusters to benzene cation.

    Science.gov (United States)

    Stein, Tamar; Bandyopadhyay, Biswajit; Troy, Tyler P; Fang, Yigang; Kostko, Oleg; Ahmed, Musahid; Head-Gordon, Martin

    2017-05-23

    The growth mechanism of hydrocarbons in ionizing environments, such as the interstellar medium (ISM), and some combustion conditions remains incompletely understood. Ab initio molecular dynamics (AIMD) simulations and molecular beam vacuum-UV (VUV) photoionization mass spectrometry experiments were performed to understand the ion-molecule growth mechanism of small acetylene clusters (up to hexamers). A dramatic dependence of product distribution on the ionization conditions is demonstrated experimentally and understood from simulations. The products change from reactive fragmentation products in a higher temperature, higher density gas regime toward a very cold collision-free cluster regime that is dominated by products whose empirical formula is (C 2 H 2 ) n + , just like ionized acetylene clusters. The fragmentation products result from reactive ion-molecule collisions in a comparatively higher pressure and temperature regime followed by unimolecular decomposition. The isolated ionized clusters display rich dynamics that contain bonded C 4 H 4 + and C 6 H 6 + structures solvated with one or more neutral acetylene molecules. Such species contain large amounts (>2 eV) of excess internal energy. The role of the solvent acetylene molecules is to affect the barrier crossing dynamics in the potential energy surface (PES) between (C 2 H 2 ) n + isomers and provide evaporative cooling to dissipate the excess internal energy and stabilize products including the aromatic ring of the benzene cation. Formation of the benzene cation is demonstrated in AIMD simulations of acetylene clusters with n > 3, as well as other metastable C 6 H 6 + isomers. These results suggest a path for aromatic ring formation in cold acetylene-rich environments such as parts of the ISM.

  6. Effect of low-oxygen-concentration layer on iron gettering capability of carbon-cluster ion-implanted Si wafer for CMOS image sensors

    Science.gov (United States)

    Onaka-Masada, Ayumi; Nakai, Toshiro; Okuyama, Ryosuke; Okuda, Hidehiko; Kadono, Takeshi; Hirose, Ryo; Koga, Yoshihiro; Kurita, Kazunari; Sueoka, Koji

    2018-02-01

    The effect of oxygen (O) concentration on the Fe gettering capability in a carbon-cluster (C3H5) ion-implanted region was investigated by comparing a Czochralski (CZ)-grown silicon substrate and an epitaxial growth layer. A high Fe gettering efficiency in a carbon-cluster ion-implanted epitaxial growth layer, which has a low oxygen region, was observed by deep-level transient spectroscopy (DLTS) and secondary ion mass spectroscopy (SIMS). It was demonstrated that the amount of gettered Fe in the epitaxial growth layer is approximately two times higher than that in the CZ-grown silicon substrate. Furthermore, by measuring the cathodeluminescence, the number of intrinsic point defects induced by carbon-cluster ion implantation was found to differ between the CZ-grown silicon substrate and the epitaxial growth layer. It is suggested that Fe gettering by carbon-cluster ion implantation comes through point defect clusters, and that O in the carbon-cluster ion-implanted region affects the formation of gettering sinks for Fe.

  7. Measurements of diameters of selectively etchable tracks produced in polymer by heavy ions

    International Nuclear Information System (INIS)

    Apel', P.Yu.

    1981-01-01

    The process of pore formation in polyethyleneterephtalate films irradiated by the 136 Xe, 84 Kr, 40 Ar ions was investigated by measuring the conductivity of the samples during etching. The diameters of the damaged tracks within which the local etching rate was larger than etching rate for non-destroyed polymer were determined. In the case of the 136 Xe ions measurements have been carried out at different ion energies [ru

  8. Fractal characterization of the silicon surfaces produced by ion beam irradiation of varying fluences

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, R.P. [Department of Physics, University of Allahabad, Allahabad, UP 211002 (India); Kumar, T. [Department of Physics, Central University of Haryana, Jant-Pali, Mahendergarh, Haryana 123029 (India); Mittal, A.K. [Department of Physics, University of Allahabad, Allahabad, UP 211002 (India); K Banerjee Centre of Atmospheric and Ocean Studies, University of Allahabad, Allahabad, UP 211002 (India); Dwivedi, S., E-mail: suneetdwivedi@gmail.com [K Banerjee Centre of Atmospheric and Ocean Studies, University of Allahabad, Allahabad, UP 211002 (India); Kanjilal, D. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, PO Box 10502, New Delhi 110 067 (India)

    2015-08-30

    Highlights: • Fractal analysis of Si(1 0 0) surface morphology at varying ion fluences. • Autocorrelation function and height–height correlation function as fractal measures. • Surface roughness and lateral correlation length increases with ion fluence. • Ripple pattern of the surfaces is found at higher ion fluences. • Wavelength of the ripple surfaces is computed for each fluence. - Abstract: Si (1 0 0) is bombarded with 200 keV Ar{sup +} ion beam at oblique incidence with fluences ranging from 3 × 10{sup 17} ions/cm{sup 2} to 3 × 10{sup 18} ions/cm{sup 2}. The surface morphology of the irradiated surfaces is captured by the atomic force microscopy (AFM) for each ion fluence. The fractal analysis is performed on the AFM images. The autocorrelation function and height–height correlation function are used as fractal measures. It is found that the average roughness, interface width, lateral correlation length as well as roughness exponent increase with ions fluence. The analysis reveals the ripple pattern of the surfaces at higher fluences. The wavelength of the ripple surfaces is computed for each ion fluence.

  9. 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

  10. Study of structure and spectroscopy of water–hydroxide ion clusters ...

    Indian Academy of Sciences (India)

    Experimen- talists are interested in determining the bonding,1–18 structure and spectroscopy of these systems and the- oreticians have contributed to the logical explanation of experimental findings. There are different types of systems ranging from atomic clusters, especially noble gas clusters (modelled by Lennard Jones ...

  11. IR photodissociation spectroscopy of (OCS){sub n}{sup +} and (OCS){sub n}{sup −} cluster ions: Similarity and dissimilarity in the structure of CO{sub 2}, OCS, and CS{sub 2} cluster ions

    Energy Technology Data Exchange (ETDEWEB)

    Inokuchi, Yoshiya, E-mail: y-inokuchi@hiroshima-u.ac.jp; Ebata, Takayuki [Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)

    2015-06-07

    Infrared photodissociation (IRPD) spectra of (OCS){sub n}{sup +} and (OCS){sub n}{sup −} (n = 2–6) cluster ions are measured in the 1000–2300 cm{sup −1} region; these clusters show strong CO stretching vibrations in this region. For (OCS){sub 2}{sup +} and (OCS){sub 2}{sup −}, we utilize the messenger technique by attaching an Ar atom to measure their IR spectra. The IRPD spectrum of (OCS){sub 2}{sup +}Ar shows two bands at 2095 and 2120 cm{sup −1}. On the basis of quantum chemical calculations, these bands are assigned to a C{sub 2} isomer of (OCS){sub 2}{sup +}, in which an intermolecular semi-covalent bond is formed between the sulfur ends of the two OCS components by the charge resonance interaction, and the positive charge is delocalized over the dimer. The (OCS){sub n}{sup +} (n = 3–6) cluster ions show a few bands assignable to “solvent” OCS molecules in the 2000–2080 cm{sup −1} region, in addition to the bands due to the (OCS){sub 2}{sup +} ion core at ∼2090 and ∼2120 cm{sup −1}, suggesting that the dimer ion core is kept in (OCS){sub 3–6}{sup +}. For the (OCS){sub n}{sup −} cluster anions, the IRPD spectra indicate the coexistence of a few isomers with an OCS{sup −} or (OCS){sub 2}{sup −} anion core over the cluster range of n = 2–6. The (OCS){sub 2}{sup −}Ar anion displays two strong bands at 1674 and 1994 cm{sup −1}. These bands can be assigned to a C{sub s} isomer with an OCS{sup −} anion core. For the n = 2–4 anions, this OCS{sup −} anion core form is dominant. In addition to the bands of the OCS{sup −} core isomer, we found another band at ∼1740 cm{sup −1}, which can be assigned to isomers having an (OCS){sub 2}{sup −} ion core; this dimer core has C{sub 2} symmetry and {sup 2}A electronic state. The IRPD spectra of the n = 3–6 anions show two IR bands at ∼1660 and ∼2020 cm{sup −1}. The intensity of the latter component relative to that of the former one becomes stronger and stronger with

  12. Electronic and geometric structures of Ge{sub n}{sup -} and Ge{sub n}{sup +} (n=5-10) clusters in comparison with corresponding Si{sub n} ions

    Energy Technology Data Exchange (ETDEWEB)

    Li Baoxing; Cao Peilin; Song Bin; Ye Zhezhen

    2003-02-10

    Using full-potential linear-muffin-tin-orbital molecular-dynamics (FP-LMTO-MD) method, we have studied the geometric and electronic structures of ionic Ge{sub 5-10} clusters. Our calculations show that the ground state structures of some Ge cluster ions are different from those of their corresponding neutral Ge clusters. Furthermore, the positive Ge ions have more severe structural distortion than the negative Ge ions due to Jahn-Teller distortion. In addition, there are differences between the ground state structures of Ge ions and Si ions, although most of the Ge ions have similar geometrical configurations to their corresponding Si ions.

  13. Thermodynamics of Small Alkali Metal Halide Cluster Ions: Comparison of Classical Molecular Simulations with Experiment and Quantum Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Vlcek, Lukas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Uhlik, Filip [Charles Univ., Prague (Czech Republic); Moucka, Filip [Purkinje Univ. (Czech Republic); Nezbeda, Ivo [Purkinje Univ. (Czech Republic); Academy of Sciences of the Czech Republic (ASCR), Prague (Czech Republic); Chialvo, Ariel A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-16

    We evaluate the ability of selected classical molecular models to describe the thermodynamic and structural aspects of gas-phase hydration of alkali halide ions and the formation of small water clusters. To understand the effect of many-body interactions (polarization) and charge penetration effects on the accuracy of a force field, we perform Monte Carlo simulations with three rigid water models using different functional forms to account for these effects: (i) point charge non-polarizable SPC/E, (ii) Drude point charge polarizable SWM4- DP, and (iii) Drude Gaussian charge polarizable BK3. Model predictions are compared with experimental Gibbs free energies and enthalpies of ion hydration, and with microscopic structural properties obtained from quantum DFT calculations. We find that all three models provide comparable predictions for pure water clusters and cation hydration, but differ significantly in their description of anion hydration. None of the investigated classical force fields can consistently and quantitatively reproduce the experimental gas phase hydration thermodynamics. The outcome of this study highlights the relation between the functional form that describes the effective intermolecular interactions and the accuracy of the resulting ion hydration properties.

  14. Molecular clusters of 3D and lower magnetic dimensionality

    International Nuclear Information System (INIS)

    Papaefthymiou, G.C

    1991-01-01

    Controlled polymerization of iron leads to the synthesis of molecular clusters of ever-increasing size, tending to extended structures. Polymerization of oxo-bridged octahedrally coordinated iron leads to clusters with 3D magnetic interactions between iron ions, while sulfide- and selenide-bridged tetrahedrally coordinated iron ions produce clusters of lower magnetic dimensionality. In this paper the magnetic properties of the resulting large molecular clusters with N ≥ 17 (where N = the number of iron ions in the cluster) are investigated for the presence of collective magnetic correlations associated with the solid state

  15. Biodiesel purification methodology produced in the RECOPE experimental plant, using ion exchange resins

    International Nuclear Information System (INIS)

    Calderon Hernandez, Teresita

    2016-01-01

    A methodology was proposed for the biodisel purification of crude palm oil produced in a plant located on the Refinadora Costarricense de Petroleo (RECOPE) campus in Alto de Ochomogo, using ion exchange resins. A comparison between two resins was carried out: the USF C-211H, which had been acquired together with the RECOPE experimental plant and the PD206 resin, which was in the process of being acquired at the time of starting the project. The biodisel was eluted by glass columns packed with each resin, to determine the saturation of the same. The percentage of free and bound glycerin and the presence of soaps were analyzed as response variables. With the results obtained, it was determined that the PD206 resin is more efficient in the removal of glycerin, soaps and methanol than the resin USF C-211H. However, neither of the two resins diminishes the acidity of the biodisel. A biodisel sample was eluted by the PD206 resin and the quality of the obtained product was analyzed. A flash point of 145 degrees was obtained. A total acid number of 0.82 mg KOH / G was shown, no presence of water or sediment was observed. The percentage value of carbon residue was 0.01% m / m, the cloud point was 12 degrees, the density at 15 degrees was 0.8713 g / cm 3 , the viscosity at 40 degrees was 2.75 mm 2 /s; the stability to oxidation was 14.5 h, the percentage of free glycerin was 0.01% m / m and the percentage of total glycerin was 0.06% m / m, finally a percentage of Fatty Acids Methyl Esters (FAME) of 98,6%. Of the analyzed parameters, all are within the limits established in the Reglamento Tecnico Centroamericano except the acidity value, which exceeds the maximum value of 0.05 mg KOH / g sample. An economic analysis was carried out to evaluate which resin provides the best option to complete the purification process of the biodisel produced. The PD206, despite being more expensive, purifies a larger volume of biodiesel, so for a better negotiation in the purchase price, this

  16. Photonic guiding structures in lithium niobate crystals produced by energetic ion beams

    Science.gov (United States)

    Chen, Feng

    2009-10-01

    A range of ion beam techniques have been used to fabricate a variety of photonic guiding structures in the well-known lithium niobate (LiNbO3 or LN) crystals that are of great importance in integrated photonics/optics. This paper reviews the up-to-date research progress of ion-beam-processed LiNbO3 photonic structures and reports on their fabrication, characterization, and applications. Ion beams are being used with this material in a wide range of techniques, as exemplified by the following examples. Ion beam milling/etching can remove the selected surface regions of LiNbO3 crystals via the sputtering effects. Ion implantation and swift ion irradiation can form optical waveguide structures by modifying the surface refractive indices of the LiNbO3 wafers. Crystal ion slicing has been used to obtain bulk-quality LiNbO3 single-crystalline thin films or membranes by exfoliating the implanted layer from the original substrate. Focused ion beams can either generate small structures of micron or submicron dimensions, to realize photonic bandgap crystals in LiNbO3, or directly write surface waveguides or other guiding devices in the crystal. Ion beam-enhanced etching has been extensively applied for micro- or nanostructuring of LiNbO3 surfaces. Methods developed to fabricate a range of photonic guiding structures in LiNbO3 are introduced. Modifications of LiNbO3 through the use of various energetic ion beams, including changes in refractive index and properties related to the photonic guiding structures as well as to the materials (i.e., electro-optic, nonlinear optic, luminescent, and photorefractive features), are overviewed in detail. The application of these LiNbO3 photonic guiding structures in both micro- and nanophotonics are briefly summarized.

  17. Clusters in nuclei. Vol. 1

    International Nuclear Information System (INIS)

    Beck, Christian

    2010-01-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is presently one of the domains of heavy-ion nuclear physics facing both the greatest challenges and opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physics decided to team up in producing a comprehensive collection of lectures and tutorial reviews covering the field. This first volume, gathering seven extensive lectures, covers the follow topics: - Cluster Radioactivity - Cluster States and Mean Field Theories - Alpha Clustering and Alpha Condensates - Clustering in Neutron-rich Nuclei - Di-neutron Clustering - Collective Clusterization in Nuclei - Giant Nuclear Molecules By promoting new ideas and developments while retaining a pedagogical nature of presentation throughout, these lectures will both serve as a reference and as advanced teaching material for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  18. Coulomb frustration of the multiphoton ionization of metallic clusters under intense EUV FEL evidenced by ion spectrometry

    International Nuclear Information System (INIS)

    Mazza, T; Devetta, M; Milani, P; Motomura, K; Liu, X-J; Fukuzawa, H; Yamada, A; Nagaya, K; Iwayama, H; Sugishima, A; Mizoguchi, Y; Saito, N; Coreno, M; Nagasono, M; Tono, K; Togashi, T; Kimura, H; Okunishi, M; Fennel, Th; Senba, Y

    2015-01-01

    Free electron laser light sources delivering high intensity pulses of short wavelength radiation are opening novel possibilities for the investigation of matter at the nanoscale and for the discovery and understanding of new physical processes occurring at the exotic transient states they make accessible. Strong ionization of atomic constituents of a nano-sized sample is a representative example of such processes and the understanding of ionization dynamics is crucial for a realistic description of the experiments. We report here on multiple ionization experiments on free clusters of titanium, a high cohesive energy metal. The time of flight ion spectra reveal a saturation of the cluster ionization at ∼10 16 photons per pulse per cm 2 . Our results also show a clear lack of any explosion process, opposite to what is observed for a rare-gas cluster under similar conditions. A simple and generalized multi-step ionization model including Coulomb frustration of the photoemission process effectively reproduces with a good agreement the main features of the experimental observation and points to an interpretation of the data involving a substantial energy deposition into the cluster through electronic system heating upon scattering events within photoemission. (paper)

  19. Measurements of ion temperature and flow of pulsed plasmas produced by a magnetized coaxial plasma gun device using an ion Doppler spectrometer

    Science.gov (United States)

    Kitagawa, Y.; Sakuma, I.; Iwamoto, D.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

    2012-10-01

    It is important to know surface damage characteristics of plasma-facing component materials during transient heat and particle loads such as type I ELMs. A magnetized coaxial plasma gun (MCPG) device has been used as transient heat and particle source in ELM simulation experiments. Characteristics of pulsed plasmas produced by the MCPG device play an important role for the plasma material interaction. In this study, ion temperature and flow velocity of pulsed He plasmas were measured by an ion Doppler spectrometer (IDS). The IDS system consists of a light collection system including optical fibers, 1m-spectrometer and a 16 channel photomultiplier tube (PMT) detector. The IDS system measures the width and Doppler shift of HeII (468.58 nm) emission line with the time resolution of 1 μs. The Doppler broadened and shifted spectra were measured with 45 and 135 degree angles with respect to the plasmoid traveling direction. The observed emission line profile was represented by sum of two Gaussian components to determine the temperature and flow velocity. The minor component at around the wavelength of zero-velocity was produced by the stationary plasma. As the results, the ion velocity and temperature were 68 km/s and 19 eV, respectively. Thus, the He ion flow energy is 97 eV. The observed flow velocity agrees with that measured by a time of flight technique.

  20. Cooling of ions trapped in potential wells produced by electromagnetic radiation fields

    International Nuclear Information System (INIS)

    Sobehart, J.R.

    1990-01-01

    The probability distributions for the ground state and the excited state of a two-level ion trapped in an harmonic potential well are studied. The ion is excited by electromagnetic radiation and relaxes back due to either spontaneous or stimulated emission. The photon statistics is considered Poissonian and the momentum transfer between the electromagnetic field and the ion is assumed discrete. The present results are closely related to the quantum treatment in the heavy particle limit as well as to those derived from previous semiclassical models. (Author) [es

  1. Radiation enhanced copper clustering processes in Fe-Cu alloys during electron and ion irradiations as measured by electrical resistivity

    International Nuclear Information System (INIS)

    Ishino, S.; Chimi, Y.; Bagiyono; Tobita, T.; Ishikawa, N.; Suzuki, M.; Iwase, A.

    2003-01-01

    To study the mechanism of radiation-enhanced clustering of copper atoms in Fe-Cu alloys, in situ electrical resistivity measurements are performed during irradiation with 100 MeV carbon ions and with 2 MeV electrons at 300 K. Two kinds of highly pure Fe-Cu alloys with Cu content of 0.02 and 0.6 wt% are used. The results are summarized as follows: - Although there is a steep initial resistivity increase below about 10 μdpa, the resistivity steadily decreases after this initial transient in Fe-0.6wt%Cu alloy, while in Fe-0.02wt%Cu alloy, the resistivity either decreases slowly or stays almost constant. The rate of change in resistivity depends on copper concentration. - The rate of change in resistivity per dpa is larger for electron irradiation than for ion irradiation. - Change in dose rate from 10 -8 to 10 -9 dpa/s slightly enhances the rate of resistivity change per dpa. The decrease in resistivity with dose is considered to be due to clustering or precipitation of copper atoms. The initial abrupt increase in resistivity is too large to be accounted for by initial introduction of point defects before copper clustering. Tentatively the phenomenon is explained as due to the formation of embryos of copper precipitates with a large strain field around them. Quantitative evaluation of the results using resistivity contribution of a unit concentration of Frenkel pairs and that of copper atoms gives an important conclusion that more than one copper atom are removed from solid solution by one Frenkel pair. The clustering efficiency is surprisingly high in the present case compared with the ordinary radiation-induced or radiation-enhanced precipitation processes

  2. Electron transfer from H2 and Ar to stored multiply charged argon ions produced by synchrotron radiation

    International Nuclear Information System (INIS)

    Kravis, S.D.; Church, D.A.; Johnson, B.M.; Meron, M.; Jones, K.W.; Levin, J.C.; Sellin, I.A.; Azuma, Y.; Berrah-Mansour, N.; Berry, H.G.; Druetta, M.

    1992-01-01

    The rate coefficients for electron transfer from Ar and H 2 to Ar q+ ions (3≤q≤6) have been measured using an ion-storage technique in a Penning ion trap. The ions were produced in the trap by K-shell photoionization of Ar atoms, using broadband synchrotron x-ray radiation. K-electron removal resulted in vacancy cascading, yielding a distribution of argon-ion charge states peaked near Ar 4+ . The stored ion gas had an initial temperature near 480 K. The basic data determining the rate coefficients k(Ar q+ ) are the storage time constants of each charge state in the trap, in the presence of a measured pressure of target gas. The results of the measurements (in units of 10 -9 cm 3 s -1 ) are k(Ar 3+ ,H 2 )=4.3(0.7), k(Ar 3+ ,Ar)=1.6(0.2), k(Ar 4+ ,H 2 )=5.2(0.6), k(Ar 4+ ,Ar)=2.5(0.3), k(Ar 5+ ,H 2 )=5.9(0.7), k(Ar 5+ ,Ar)=2.9(0.3), k(Ar 6+ ,H 2 )=8.5(1.2), and k(Ar 6+ ,Ar)=2.5(0.3)

  3. Modification on surface oxide layer structure and surface morphology of niobium by gas cluster ion beam treatments

    International Nuclear Information System (INIS)

    Wu, A.T.; Swenson, D.R.; Insepov, Z.

    2010-01-01

    Recently, it was demonstrated that significant reductions in field emission on Nb surfaces could be achieved by means of a new surface treatment technique called gas cluster ion beam (GCIB). Further study as shown in this paper revealed that GCIB treatments could modify surface irregularities and remove surface asperities leading to a smoother surface finish as demonstrated through measurements using a 3D profilometer, an atomic force microscope, and a scanning electron microscope. These experimental observations were supported by computer simulation via atomistic molecular dynamics and a phenomenological surface dynamics. Measurements employing a secondary ion mass spectrometry found that GCIB could also alter Nb surface oxide layer structure. Possible implications of the experimental results on the performance of Nb superconducting radio frequency cavities treated by GCIB will be discussed. First experimental results on Nb single cell superconducting radio frequency cavities treated by GCIB will be reported.

  4. Graphene synthesis on SiC: Reduced graphitization temperature by C-cluster and Ar-ion implantation

    International Nuclear Information System (INIS)

    Zhang, R.; Li, H.; Zhang, Z.D.; Wang, Z.S.; Zhou, S.Y.; Wang, Z.; Li, T.C.; Liu, J.R.; Fu, D.J.

    2015-01-01

    Thermal decomposition of SiC is a promising method for high quality production of wafer-scale graphene layers, when the high decomposition temperature of SiC is substantially reduced. The high decomposition temperature of SiC around 1400 °C is a technical obstacle. In this work, we report on graphene synthesis on 6H–SiC with reduced graphitization temperature via ion implantation. When energetic Ar, C 1 and C 6 -cluster ions implanted into 6H–SiC substrates, some of the Si–C bonds have been broken due to the electronic and nuclear collisions. Owing to the radiation damage induced bond breaking and the implanted C atoms as an additional C source the graphitization temperature was reduced by up to 200 °C

  5. Collision-Induced Dissociation Study of Strong Hydrogen-Bonded Cluster Ions Y-(HF) n (Y=F, O2) Using Atmospheric Pressure Corona Discharge Ionization Mass Spectrometry Combined with a HF Generator.

    Science.gov (United States)

    Sakamoto, Kenya; Sekimoto, Kanako; Takayama, Mitsuo

    2017-01-01

    Hydrogen fluoride (HF) was produced by a homemade HF generator in order to investigate the properties of strong hydrogen-bonded clusters such as (HF) n . The HF molecules were ionized in the form of complex ions associated with the negative core ions Y - produced by atmospheric pressure corona discharge ionization (APCDI). The use of APCDI in combination with the homemade HF generator led to the formation of negative-ion HF clusters Y - (HF) n (Y=F, O 2 ), where larger clusters with n ≥4 were not detected. The mechanisms for the formation of the HF, F - (HF) n , and O 2 - (HF) n species were discussed from the standpoints of the HF generator and APCDI MS. By performing energy-resolved collision-induced dissociation (CID) experiments on the cluster ions F - (HF) n ( n =1-3), the energies for the loss of HF from F - (HF) 3 , F - (HF) 2 , and F - (HF) were evaluated to be 1 eV or lower, 1 eV or higher, and 2 eV, respectively, on the basis of their center-of-mass energy ( E CM ). These E CM values were consistent with the values of 0.995, 1.308, and 2.048 eV, respectively, obtained by ab initio calculations. The stability of [O 2 (HF) n ] - ( n =1-4) was discussed on the basis of the bond lengths of O 2 H-F - (HF) n and O 2 - H-F(HF) n obtained by ab initio calculations. The calculations indicated that [O 2 (HF) 4 ] - separated into O 2 H and F - (HF) 3 .

  6. Effect of irradiation angle on the efficiency of formation of multiply charged ions in a laser-produced plasma

    International Nuclear Information System (INIS)

    Bedilov, M R; Beisembaeva, Kh B; Tsoi, T G; Satybaldiev, T B; Sabitov, M S

    2000-01-01

    Mass spectrometry is used to investigate the emission behaviour and the characteristics of multiply charged ions in a plasma produced at small angles of incidence of laser radiation (α∼20 0 ) and also at grazing incidence (α∼85 0 ). It is found that upon grazing incidence of the laser radiation onto a target, the efficiency of production of multiply charged ions is reduced compared to that for α∼20 0 . However, this geometry of laser irradiation of solids can be used for the elemental analysis of surface layers of a sample. (interaction of laser radiation with matter. laser plasma)

  7. Physical principles of the surface plasma method for producing beams of negative ions

    International Nuclear Information System (INIS)

    Bel'chenko, Yu.I.; Dimov, G.I.; Dudnikov, V.G.

    1977-01-01

    The processes which are important for the production of intense beams of negative ions from surface plasma sources (SPS) are examined. The formation of negative ions when atomic particles interact with a surface is analyzed on the basis of both experimental results obtained when a surface was bombarded with beams and recently developed theoretical considerations of reflection, scattering, and electron exchange. The characteristic features of these processes in SPS, when a surface is bombarded with intense fluxes of plasma particles, are revealed in special experiments. The characteristics of generation and acceleration of the bombarding particles in a gas discharge SPS plasma, the characteristics of transportation of negative ions through the plasma toward the beam forming system, the role of cesium in SPS, and the characteristics of formation of the intense negative ion beams as well as the removal of parasite electrons from the beam

  8. High energy density in matter produced by heavy ion beams. Annual report 1993

    International Nuclear Information System (INIS)

    1994-06-01

    The experimental activities at GSI were concentrated on the progress in beam-plasma interaction experiments of heavy ion with ionized matter, plasma -lens forming devices, intense beam at high temperature experimental area, and charge exchange collisions of ions. The development to higher intensities and phase space densities during 1993 for the SIS and the ESR is recorded. The possibility of studying of funneling of two beams in a two-beam RFQ is studied. Specific results are presented with respect to inertial confinement fusion (ICF). The problem of ion stopping in plasma and pumping X-ray lasers with heavy ion beams are discussed. Various contributions deal with dense plasma effects, shocks and opacity. (HP)

  9. Genetic interrelations in the actinomycin biosynthetic gene clusters of Streptomyces antibioticus IMRU 3720 and Streptomyces chrysomallus ATCC11523, producers of actinomycin X and actinomycin C

    Science.gov (United States)

    Crnovčić, Ivana; Rückert, Christian; Semsary, Siamak; Lang, Manuel; Kalinowski, Jörn; Keller, Ullrich

    2017-01-01

    Sequencing the actinomycin (acm) biosynthetic gene cluster of Streptomyces antibioticus IMRU 3720, which produces actinomycin X (Acm X), revealed 20 genes organized into a highly similar framework as in the bi-armed acm C biosynthetic gene cluster of Streptomyces chrysomallus but without an attached additional extra arm of orthologues as in the latter. Curiously, the extra arm of the S. chrysomallus gene cluster turned out to perfectly match the single arm of the S. antibioticus gene cluster in the same order of orthologues including the the presence of two pseudogenes, scacmM and scacmN, encoding a cytochrome P450 and its ferredoxin, respectively. Orthologues of the latter genes were both missing in the principal arm of the S. chrysomallus acm C gene cluster. All orthologues of the extra arm showed a G +C-contents different from that of their counterparts in the principal arm. Moreover, the similarities of translation products from the extra arm were all higher to the corresponding translation products of orthologue genes from the S. antibioticus acm X gene cluster than to those encoded by the principal arm of their own gene cluster. This suggests that the duplicated structure of the S. chrysomallus acm C biosynthetic gene cluster evolved from previous fusion between two one-armed acm gene clusters each from a different genetic background. However, while scacmM and scacmN in the extra arm of the S. chrysomallus acm C gene cluster are mutated and therefore are non-functional, their orthologues saacmM and saacmN in the S. antibioticus acm C gene cluster show no defects seemingly encoding active enzymes with functions specific for Acm X biosynthesis. Both acm biosynthetic gene clusters lack a kynurenine-3-monooxygenase gene necessary for biosynthesis of 3-hydroxy-4-methylanthranilic acid, the building block of the Acm chromophore, which suggests participation of a genome-encoded relevant monooxygenase during Acm biosynthesis in both S. chrysomallus and S

  10. Arrays of Size-Selected Metal Nanoparticles Formed by Cluster Ion Beam Technique

    DEFF Research Database (Denmark)

    Ceynowa, F. A.; Chirumamilla, Manohar; Zenin, Volodymyr

    2018-01-01

    Deposition of size-selected copper and silver nanoparticles (NPs) on polymers using cluster beam technique is studied. It is shown that ratio of particle embedment in the film can be controlled by simple thermal annealing. Combining electron beam lithography, cluster beam deposition, and heat...... with required configurations which can be applied for wave-guiding, resonators, in sensor technologies, and surface enhanced Raman scattering....

  11. Ion beam mixing to produce disordered AlSi superconducting alloys

    International Nuclear Information System (INIS)

    Xi Xiaoxing; Ran Qize; Liu Jiarui; Guan Weiyan

    1987-01-01

    Multilayered Al/Si films were bombarded with Ar ions at LHe temperature and superconducting transition temperature Tsub(c) was measured in situ. The highest Tsub(c) thus obtained was 7.53 K. The systematic studies on samples with different compositions suggest that ion induced disorder might be the main reason for Tsub(c) enhancement in these AlSi alloys. (author)

  12. Angular correlation of the N+ ions produced in the dissociative double ionization of nitrogen

    International Nuclear Information System (INIS)

    Ezell, R.L.; Edwards, A.K.; Wood, R.M.

    1984-01-01

    The double ionization of N 2 by He + projectiles was studied by measuring the angular correlation between the two N + ions emitted in the dissociation of N 2+ 2 molecular ions. If there were no recoil velocity imposed on the N 2+ 2 ion in the initial ionizing collision, and thermal effects were neglected, the pair of N + ions would have equal and opposite velocity vectors in the laboratory frame of reference. Measuring the coincidence yield of pairs of N + ions as a function of the angle between their velocity vectors permits an estimate to be made of the component of momentum transferred to the N 2+ 2 parent ions in the beam direction. The results presented in this report show the recoil velocity to be considerably less than the mean thermal velocity of N 2 molecules at room temperature. We also report mesurements of the relative cross section for N + production from N 2+ 2 as a function of the orientation of the N 2 target molecules relative to the projectile beam axis

  13. Statistics of high-altitude and high-latitude O+ ion outflows observed by Cluster/CIS

    Directory of Open Access Journals (Sweden)

    A. Korth

    2005-07-01

    Full Text Available The persistent outflows of O+ ions observed by the Cluster CIS/CODIF instrument were studied statistically in the high-altitude (from 3 up to 11 RE and high-latitude (from 70 to ~90 deg invariant latitude, ILAT polar region. The principal results are: (1 Outflowing O+ ions with more than 1keV are observed above 10 RE geocentric distance and above 85deg ILAT location; (2 at 6-8 RE geocentric distance, the latitudinal distribution of O+ ion outflow is consistent with velocity filter dispersion from a source equatorward and below the spacecraft (e.g. the cusp/cleft; (3 however, at 8-12 RE geocentric distance the distribution of O+ outflows cannot be explained by velocity filter only. The results suggest that additional energization or acceleration processes for outflowing O+ ions occur at high altitudes and high latitudes in the dayside polar region. Keywords. Magnetospheric physics (Magnetospheric configuration and dynamics, Solar wind-magnetosphere interactions

  14. Structure carbon materials: clusters, nanotubes, ion-implant polymers and diamonds

    International Nuclear Information System (INIS)

    Lapchuk, N.M.; Odzhaev, V.B.; Poklonskij, N.A.; Sviridov, D.V.

    2009-01-01

    The paper summarizes the series of research works dealing with the physics of nanostructured carbon materials, which were awarded a Sevchenko Prize in 2008. The paper considers the mechanism of synthesis of 3D carbon nanospecies and their nanomechanics, magnetic properties of ion-implanted diamonds, as well as the regularities of formation of novel forms of amorphous hydrogenated carbon and metal-carbon nanocomposites via ion bombardment of polymers, as well as electronic, magnetic, and structural properties of ion-implanted polymers an their possible applications in micro- and nanoelectronics. (authors)

  15. Multiply charged ions of the oxygen - produced at interaction of laser radiation with two-element solids

    International Nuclear Information System (INIS)

    Bedilov, M.R.; Bedilov, R.M.; Kamalova, J.O.; Davletov, I.Yu.; Matnazarov, A.R.

    2007-01-01

    Full text: The interest to study of the oxygen multiply charged ions spectra produced at interaction laser radiation with one and two-element solids, is associate with possibility of creating laser and inertial thermonuclear syntheses, effective sources of multiply charged ions and nuclei atoms elements, plasma lasers, lasers on multiply charged transition, design of radiation-resistant materials and others. The present time many works is devoted to multiply charged ions, obtained from one element targets. Experimental results of study charge and energy spectra multiply charged ions of the oxygen, formed at interaction laser radiation with one and two-element solids are given in this work. Our experiments, we used installation, which is described in [1]. Neodymium laser had following parameters: wavelength 1.06 μm; intensity q = (0.1 h 1000) GW/sm 2 ; angle of incidence = 180. Were study one element Al, and two-element Al 2 O 3 , Y 2 O 3 targets by a diameter of 10 mm and thickness of 3 mm. Analysis obtained charge and energy spectra of multiply charged ions one (Al) and two-element (Al 2 O 3 , Y 2 O 3 ) targets depending on intensity of laser radiation and targets components reveal the following: - maximal charge number one element target (Al) at q 500 GW/sm 2 is equal Z max = 6 and all peaks corresponding to charge numbers Z = 1 - 6 well resolved, but two-element targets (Al 2 O 3 ) Z max ions Al decrease before 3. Also it is necessary to note that, Z max ions of the oxygen depend on target components. In case Al 2 O 3 and Y 2 O 3 maximal charge number of oxygen ions are equal Z max = 6 and 3, accordingly; - obtained charge and energy spectra of oxygen ions being included in two-element targets, are indicative of that, general regularities of the change Z max , E max and structures charge and energy spectra depending on q laser are saved. However they hang by target components; - common features and some differences of energy spectra multiply charged oxygen ions

  16. Ionization Capabilities of Hydronium Ions and High Electric Fields Produced by Atmospheric Pressure Corona Discharge.

    Science.gov (United States)

    Sato, Natsuhiko; Sekimoto, Kanako; Takayama, Mitsuo

    2016-01-01

    Atmospheric pressure corona discharge (APCD) was applied to the ionization of volatile organic compounds. The mass spectra of analytes having aromatic, phenolic, anilinic, basic and aliphatic in nature were obtained by using vapor supply and liquid smear supply methods. The vapor supply method mainly gave protonated analytes [A+H] + caused by proton transfer from hydronium ion H 3 O + , except for benzene, toluene and n -hexane that have lower proton affinity. The use of the liquid smear supply method resulted in the formation of molecular ion A ·+ and/or dehydride analyte [A-H] + , according to the nature of analytes used. The formation of A ·+ without fragment ions could be explained by the electron tunneling via high electric fields 10 8  V/m at the tip of the corona needle. The dehydride analytes [A-H] + observed in the mass spectra of n -hexane, di- and tributylamines may be explained by the hydride abstraction from the alkyl chains by the hydronium ion. The hydronium ion can play the two-roles for analytes, i.e. , the proton donor to form [A+H] + and the hydride acceptor to form [A-H] + .

  17. Confinement characteristics of high-energy ions produced by ICRF heating in the large helical device

    International Nuclear Information System (INIS)

    Kumazawa, R; Saito, K; Torii, Y; Mutoh, T; Seki, T; Watari, T; Osakabe, M; Murakami, S; Sasao, M; Watanabe, T; Yamamoto, T; Notake, T; Takeuchi, N; Saida, T; Shimpo, F; Nomura, G; Yokota, M; Kato, A; Zao, Y; Okada, H; Isobe, M; Ozaki, T; Narihara, K; Nagayama, Y; Inagaki, S; Morita, S; Krasilnikov, A V; Idei, H; Kubo, S; Ohkubo, K; Sato, M; Shimozuma, T; Yoshimura, Y; Ikeda, K; Nagaoka, K; Oka, Y; Takeiri, Y; Tsumori, K; Ashikawa, N; Emoto, M; Funaba, H; Goto, M; Ida, K; Kobuchi, T; Liang, Y; Masuzaki, S; Minami, T; Miyazawa, J; Morisaki, T; Muto, S; Nakamura, Y; Nakanishi, H; Nishimura, K; Noda, N; Ohdachi, S; Peterson, B J; Sagara, A; Sakakibara, S; Sakamoto, R; Sato, K; Shoji, M; Suzuki, H; Tanaka, K; Toi, K; Tokuzawa, T; Watanabe, K Y; Yamada, I; Yamamoto, S; Yoshinuma, M; Yokoyama, M; Watanabe, K-Y; Kaneko, O; Kawahata, K; Komori, A; Ohyabu, N; Yamada, H; Yamazaki, K; Sudo, S; Matsuoka, K; Hamada, Y; Motojima, O; Fujiwara, M

    2003-01-01

    The behaviour of high-energy ions accelerated by an ion cyclotron range of frequency (ICRF) electric field in the large helical device (LHD) is discussed. A better confinement performance of high-energy ions in the inward-shifted magnetic axis configuration was experimentally verified by measuring their energy spectrum and comparing it with the effective temperature determined by an electron slowing down process. In the standard magnetic axis configuration a saturation of the measured tail temperature was observed as the effective temperature was increased. The ratio between these two quantities is a measure of the quality of transfer efficiency from high-energy ions to a bulk plasma; when this efficiency was compared with Monte Carlo simulations the results agreed fairly well. The ratio of the stored energy of the high-energy ions to that of the bulk plasma was measured using an ICRF heating power modulation method; it was deduced from phase differences between total and bulk plasma stored energies and the modulated ICRF heating power. The measured high energy fraction agreed with that calculated using the injected ICRF heating power, the transfer efficiency determined in the experiment and the confinement scaling of the LHD plasma

  18. High dislocation density structures and hardening produced by high fluency pulsed-ion-beam implantation

    International Nuclear Information System (INIS)

    Sharkeev, Yu.P.; Didenko, A.N.; Kozlov, E.V.

    1994-01-01

    The paper presents a review of experimental data on the ''long-range effect'' (a change in dislocation structure and in physicomechanical properties at distances considerably greater than the ion range value in ion-implanted metallic materials and semiconductors). Our results of electron microscopy studies of high density dislocation structure in ion-implanted metallic materials with different initial states are given. It has been shown that the nature of the dislocation structure and its quantitative characteristics in the implanted metals and alloys depend on the target initial state, the ion type and energy and the retained dose. The data obtained by different workers are in good agreement both with our results and with each other as well as with the results of investigation of macroscopic characteristics (wear resistance and microhardness). It has been established that the ''long-range effect'' occurs in metallic materials with a low yield point or high plasticity level and with little dislocation density in their initial state prior to ion implantation. ((orig.))

  19. Energy distribution of ions produced by laser ablation of silver in vacuum

    International Nuclear Information System (INIS)

    Toftmann, B.; Schou, J.; Canulescu, S.

    2013-01-01

    The ion energy in a silver ablation plume for fluence in the range of 0.6–2.4 J cm −2 , typical for a pulsed laser deposition (PLD) experiment has been investigated. In this fluence range the ion fraction of the ablated particles becomes gradually dominant and can be utilized to characterize the ablation process. A silver target in vacuum was irradiated with a Nd:YAG laser at a wavelength of 355 nm and detailed measurements of the time-resolved angular distribution of plume ions were made. In contrast to earlier work, the beam spot was circular such that any flip-over effect of the plume is avoided. The angular energy distribution of ions in forward direction exceeds values of 500 eV, while at large angles the ion energy tail is below 100 eV. The maximum for the time-of-flight distributions agrees consistently with the prediction of Anisimov's model in the low fluence range, in which hydrodynamic motion prevails.

  20. On the application of the weak-beam technique to the determination of the sizes of small point-defect clusters in ion-irradiated copper

    International Nuclear Information System (INIS)

    Jenkins, M. L.

    1998-01-01

    We have made an analysis of the conditions necessary for the successful use of the weak-beam technique for identifying and characterizing small point-defect clusters in ion-irradiated copper. The visibility of small defects was found to depend only weakly on the magnitude of the beam-convergence. In general, the image sizes of small clusters were found to be most sensitive to the magnitude of Sa with the image sizes of some individual defects changing by large amounts with changes as small as 0.025 nm -1 . The most reliable information on the true defect size is likely to be obtained by taking a series of 5-9 micrographs with a systematic variation of deviation parameter from 0.2-0.3 nm -1 . This procedure allows size information to be obtained down to a resolution limit of about 0.5 nm for defects situated throughout a foil thickness of 60 nm. The technique has been applied to the determination of changes in the sizes of small defects produced by a low-temperature in-situ irradiation and annealing experiment

  1. Molecular depth profiling of trehalose using a C{sub 60} cluster ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Wucher, Andreas [Department of Physics, University of Duisburg-Essen, D-47048 Duisburg (Germany)], E-mail: andreas.wucher@uni-due.de; Cheng Juan; Winograd, Nicholas [Department of Chemistry, Pennsylvania State University, University Park, PA 16802 (United States)

    2008-12-15

    Molecular depth profiling of organic overlayers was performed using a mass selected fullerene ion beam in conjunction with time-of-flight (TOF-SIMS) mass spectrometry. The characteristics of depth profiles acquired on a 300-nm trehalose film on Si were studied as a function of the impact kinetic energy and charge state of the C{sub 60} projectile ions. We find that the achieved depth resolution depends only weakly upon energy.

  2. Proximity gettering technology for advanced CMOS image sensors using carbon cluster ion-implantation technique. A review

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Kazunari; Kadono, Takeshi; Okuyama, Ryousuke; Shigemastu, Satoshi; Hirose, Ryo; Onaka-Masada, Ayumi; Koga, Yoshihiro; Okuda, Hidehiko [SUMCO Corporation, Saga (Japan)

    2017-07-15

    A new technique is described for manufacturing advanced silicon wafers with the highest capability yet reported for gettering transition metallic, oxygen, and hydrogen impurities in CMOS image sensor fabrication processes. Carbon and hydrogen elements are localized in the projection range of the silicon wafer by implantation of ion clusters from a hydrocarbon molecular gas source. Furthermore, these wafers can getter oxygen impurities out-diffused to device active regions from a Czochralski grown silicon wafer substrate to the carbon cluster ion projection range during heat treatment. Therefore, they can reduce the formation of transition metals and oxygen-related defects in the device active regions and improve electrical performance characteristics, such as the dark current, white spot defects, pn-junction leakage current, and image lag characteristics. The new technique enables the formation of high-gettering-capability sinks for transition metals, oxygen, and hydrogen impurities under device active regions of CMOS image sensors. The wafers formed by this technique have the potential to significantly improve electrical devices performance characteristics in advanced CMOS image sensors. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Energy distribution of ions produced by laser ablation of silver in vacuum

    DEFF Research Database (Denmark)

    Christensen, Bo Toftmann; Schou, Jørgen; Canulescu, Stela

    2013-01-01

    the ablation process. A silver target in vacuum was irradiated with a Nd:YAG laser at a wavelength of 355nm and detailed measurements of the time-resolved angular distribution of plume ions were made. In contrast to earlier work, the beam spot was circular such that any flip-over effect of the plume is avoided......The ion energy in a silver ablation plume for fluence in the range of 0.6–2.4Jcm−2, typical for a pulsed laser deposition (PLD) experiment has been investigated. In this fluence range the ion fraction of the ablated particles becomes gradually dominant and can be utilized to characterize...

  4. Recent developments of target and ion sources to produce ISOL beams

    CERN Document Server

    Stora, Thierry

    2013-01-01

    In this review on target and ion sources for ISOL (Isotope Separation OnLine) beams, important develop- ments from the past five years are highlighted. While at precedent EMIS conferences, a particular focus was given to a single topics, for instance specifically on ion sources or on chemical purification tech- niques, here each of the important elements present in an ISOL production unit is discussed. Fast diffus- ing nanomaterials, uranium-based targets, high power targets for next generation facilities, purification by selective adsorption, new ion sources are all part of this review. For each of these selected topics, the reported results lead to significant gains in intensity, purity, or quality of the delivered beam, or in the production of new isotope beams. Often the outcome resulted from the combination of original ideas with state-of-the-art investigations; this was carried out using very different scientific disciplines, lead- ing to understanding of the underlying chemical or physical mechanisms a...

  5. Extraction of volume produced H- or D- ions from a sheet plasma, 2

    International Nuclear Information System (INIS)

    Uramoto, Joshin.

    1984-02-01

    A development to large area H - or D - ion source is tried by using three extraction electrodes: The first electrode bias voltage is set near the wall potential (floating), the second electrode is set near 13 % of main extraction voltage and the third electrode is the main acceleration electrode. An ion current of 13 mA (3.3 mA/cm 2 ) for H - or 11 mA (2.8 mA/ cm 2 ) for D - at 3 KeV is extracted from 9 apertures of 6 mm phi in 4 cm 2 outside of the sheet plasma (14 cm wide and 1.0 cm thick) under a pressure of 7.7 x 10 -4 H2 or D2 gas and a weak magnetic field 50 gauss. Then, it is noted that the corresponding electron current is suppressed below 1/10 of the H - or D - ion current. (author)

  6. Two-dimensional evaluation of an ion plasma produced by pulsed lasers extracted by non-parallel collectors

    International Nuclear Information System (INIS)

    Mahdieh, M H; Gavili, A

    2003-01-01

    Two-dimensional hydrodynamics of ion extraction from quasi-neutral plasmas has been calculated numerically for non-parallel ion extractors, and the results compared with those for the parallel case. The ions were assumed to be initially uniform with a very steep density profile at the boundaries, and held between two non-parallel metal plates as cathode and anode with fixed potentials. Experimentally, tunable pulsed lasers through stepwise photo-excitation and photo-ionization or multi-photo-ionization processes can produce such plasma. Poisson's equation was solved simultaneously with the equations of mass and momentum, assuming the Maxwell-Boltzmann distribution for electrons. Ordinary Cartesian co-ordinates are not suitable for the rotated extractor geometry; therefore using the 'algebraic method' a transformation from the physical domain into the computational rectangular plane is applied for analysing the irregular boundaries. Such a technique provides adequate resolution for the boundary layer. Using a first-order explicit upwind differencing in an appropriate transformed Cartesian co-ordinate system, the hydrodynamics of the plasma ions between the two non-parallel electrodes was evaluated. In these calculations electric potential, ion density between the two electrodes, and the extraction time were assessed, considering three separate regions for the plasma, i.e. the ion sheath where (n i >>n e ∼0), the transition region (pre-sheath) (n i = n e ), and the quasi-neutral plasma (n i -n e i ). The results were compared with those for parallel electrodes. A significant discrepancy was found between the two results. From the calculation, the non-uniform asymmetric potential contour, and the ion density contour across the plasma, were obtained for the non-parallel electrodes. For comparison with the parallel extractors, we have also obtained almost the same extraction time for the non-parallel extractors

  7. Semiconductor detectors for observation of multi-MeV protons and ions produced by lasers

    Czech Academy of Sciences Publication Activity Database

    Krása, Josef; Klir, D.; De Marco, Massimo; Cikhardt, J.; Velyhan, Andriy; Řezáč, Karel; Pfeifer, Miroslav; Krouský, Eduard; Ryć, L.; Dostál, Jan; Kaufman, Jan; Ullschmied, Jiří; Limpouch, J.

    2016-01-01

    Roč. 3, č. 1 (2016), 9-11 ISSN 2336-2626 R&D Projects: GA ČR GA16-07036S; GA MŠk EF15_008/0000162; GA MŠk(CZ) LD14089 Grant - others:ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : laser-accelerated ions * ion collectors * SiC detectors * similarity relations * electromagnetic pulse Subject RIV: BL - Plasma and Gas Discharge Physics

  8. Broadening of ICRH produced fast ion profiles due to orbit effects

    International Nuclear Information System (INIS)

    Eriksson, L.-G.; Porcelli, F.

    1991-01-01

    In the JET tokamak, minority ions accelerated by ICRH reach energies in the MeV range. Near the plasma magnetic axis, the standard trapped particle ''banana'' orbit is distorted into a ''potato'' or ''fat banana'' orbit. The zero banana width approximation which is used in most Fokker-Planck calculations of velocity distributions of resonating ions is often not valid in JET. The inclusion of finite banana width effects will, in general, lead to a lowering of the averaged tail energy and a broadening of pressure profiles, power transfer profiles etc. A model for calculating orbit broadened profiles is presented. (Author)

  9. The structure of small clusters ejected by ion bombardment of solids

    International Nuclear Information System (INIS)

    Ali, M.; Smith, R.

    1993-01-01

    The structure of small clusters predicted by the many-body potentials used in Molecular Dynamics (MD) simulations of semiconductor processes is investigated. The potential minima are determined by using global optimisation algorithms which also find the local minima. It is shown that there are many such local minima for the Tersoff type potentials. If an MD simulation requires an accurate description of the small cluster geometries and energetics, then the potential can describe them provided they are included in the fitting process. (Author)

  10. A Mutant of Bacillus Subtilis with High-Producing Surfactin by Ion Beam Implantation

    International Nuclear Information System (INIS)

    Liu Qingmei; Yuan Hang; Wang Jun; Gong Guohong; Zhou Wei; Fan Yonghong; Wang Li; Yao Jianming; Yu Zengliang

    2006-01-01

    In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological changes in the bacteria were observed by scanning electron microscope (SEM). The optimum condition of ions implantation, 20 keV of energy and 2.6x10 15 N + /cm 2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wild strain. The microbial growth and biosurfactant production of both the mutant and the wild strain were compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was determined to be a complex of surfactin family through analysis of electrospray ionization mass spectrum (ESI/MS) and there was an interesting finding that after the ion beam implantation the intensities of the components were different from the wild type strain

  11. Three-body fragmentation of methane dications produced by slow A r8 + -ion impact

    Science.gov (United States)

    Zhang, Y.; Jiang, T.; Wei, L.; Luo, D.; Wang, X.; Yu, W.; Hutton, R.; Zou, Y.; Wei, B.

    2018-02-01

    The three-body fragmentation dynamics of CH4 2 + dications induced by single-electron capture of slow (3-keV/u) A r8 + ions is investigated. The experiment is performed on a newly built, highly charged ion collision platform which consists of an electron cyclotron resonance ion source and a cold target recoil ion momentum spectroscopy (COLTRIMS) setup. Using the COLTRIMS methodology, the complete kinematical information is determined for two three-body breakup channels, CH4 2 +→H++CH2 ++H and CH4 2 +→H2 ++C H++H . Then analyzing the complete kinematics with the Dalitz plot, very different fragmentation mechanisms (e.g., sequential and/or concerted pathway) are clearly identified for the two channels. To confirm the existence of some possible fragmentation pathways, we also simulate corresponding Dalitz plots employing a simple classical mechanical model. For the H++CH2 ++H channel, the dependence of the fragmentation pathway on its kinetic energy release is studied, which reflects the different nature of the corresponding states of CH4 2 + dications. Furthermore, the kinetic energy ratio of two ionic fragments is analyzed to infer the three-body fragmentation mechanism of CH4 2 + dications.

  12. Scaling of x-ray emission and ion velocity in laser produced Cu ...

    Indian Academy of Sciences (India)

    Laser plasma; x-ray emission; conversion efficiency; ion velocities. ... fits from this kind of optimization studies are in the fields of x-ray lithography, x-ray lasers etc. .... formula between the x-ray conversion rate versus different parameters of the ...

  13. Stream mesocosm response sensitivities to simulated ion stress in produced waters from resource extraction activities

    Science.gov (United States)

    To increase the ecological relevance of laboratory exposures intent on determining species sensitivity to ion stress from resource extraction activities we have conducted several stream mesocosm dosing studies that pair single-species and community-level responses in-situ and all...

  14. Kossel and Okorokov effect like processes produced by ions in crystalline targets

    International Nuclear Information System (INIS)

    Aginian, M.A.; Ispiryan, K.A.; Ispiryan, M.K.

    2011-01-01

    It is shown that taking into account the energy levels of ions and/or of the crystalline atoms some new processes with consequences similar to the Kossel and Okorokov effects can take place when certain additional resonance conditions are satisfied

  15. Bose-Einstein correlations between hard photons produced in heavy ions collisions

    International Nuclear Information System (INIS)

    Marques Moreno, F.M.

    1994-06-01

    Heavy-ion collisions offer the unique possibility to create in the laboratory nuclear matter far from equilibrium. The electromagnetic probe constituted by hard photons and the Bose-Einstein correlations were used to study the properties of such a matter (size, density, temperature...). It is shown how the formalism has evolved from Young experiments to heavy-ion collisions experiments. The experiments performed with the photon multidetector TAPS at Ganil are described. The systems studied are: 86 KR + nat Ni at 60.0 A.MeV, and 181 Ta + 197 Au at 39.5 A.MeV. Results are presented concerning the production of gamma, pi 0 , e +- and γγ correlation. The results are interpreted with the help of static and dynamic calculations describing hard photon production in heavy ion collisions. For the first time in Nuclear Physics, the existence of the Bose-Einstein effect for photons in the range of gamma is demonstrated, and the existence of two different photon sources is postulated, reflecting the density oscillations taking place in the nuclear matter created in heavy-ion collisions. (from author) 55 figs., 22 tabs., 76 refs

  16. Dual beam organic depth profiling using large argon cluster ion beams

    Science.gov (United States)

    Holzweber, M; Shard, AG; Jungnickel, H; Luch, A; Unger, WES

    2014-01-01

    Argon cluster sputtering of an organic multilayer reference material consisting of two organic components, 4,4′-bis[N-(1-naphthyl-1-)-N-phenyl- amino]-biphenyl (NPB) and aluminium tris-(8-hydroxyquinolate) (Alq3), materials commonly used in organic light-emitting diodes industry, was carried out using time-of-flight SIMS in dual beam mode. The sample used in this study consists of a ∽400-nm-thick NPB matrix with 3-nm marker layers of Alq3 at depth of ∽50, 100, 200 and 300 nm. Argon cluster sputtering provides a constant sputter yield throughout the depth profiles, and the sputter yield volumes and depth resolution are presented for Ar-cluster sizes of 630, 820, 1000, 1250 and 1660 atoms at a kinetic energy of 2.5 keV. The effect of cluster size in this material and over this range is shown to be negligible. © 2014 The Authors. Surface and Interface Analysis published by John Wiley & Sons Ltd. PMID:25892830

  17. Ultrahigh-sensitive detection of molecules produced in catalytic reactions by uni-atomic-composition bi-element clusters supported on solid substrate

    International Nuclear Information System (INIS)

    Yasumatsu, H; Fukui, N

    2013-01-01

    An apparatus has been developed for measuring catalytic activities of uni-atomic-composition bi-element clusters supported on a solid substrate. The cluster sample is prepared by irradiating a cluster-ion beam having the uni-atomic composition onto the substrate on a soft-landing condition in an ultra-high vacuum. The catalytic activity is measured by temperature-programmed desorption (TPD) mass analysis. Molecules at a density as low as 3 cm −3 have been detected with an ultrahigh-sensitive TPD mass spectrometer consisting of a cylindrical electron gun, a quadrupole mass filter and a micro-channel-plate ion-detector. The high reproducibility has been achieved by careful calibration of the TPD mass spectrometer. As a benchmark example, thermal oxidation of CO catalysed on Pt 30 disks supported on a silicon surface was studied. The CO 2 products have been successfully observed at the Pt 30 density as low as 3 × 10 12 clusters in a circular area of 8 mm in diameter at the ramping rate of the sample temperature as low as 0.3 K s −1 .

  18. Intense pulsed sources of ions and electrons produced by lasers; Sources pulsees intenses d'ions et d'electrons produites par laser

    Energy Technology Data Exchange (ETDEWEB)

    Bourrabier, G [Centre de Recherche de la C.S.F., Corbeville (France); Consoli, T; Slama, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-11-01

    We describe a device for the acceleration of the plasma burst produced by focusing a laser beam into a metal target. We extract the electrons and the ions from the plasma. The maximum current is around 2000 amperes during few microseconds. The study of the effect of the kind of the target on the characteristics of the current shows the great importance of the initial conditions that is the ionisation potential of the target and the energy laser. (authors) [French] On decrit un dispositif destine a accelerer la bouffee de plasma produite par focalisation d'un faisceau laser sur une cible solide. On extrait du plasma les electrons et les ions. Le courant maximum atteint pres de 2000 amperes pendant quelques microsecondes. L'etude de l'effet de la nature de la cible sur les caracteristiques du courant collecte, met en evidence l'importance des conditions initiales (potentiel d'ionisation de la cible, energie du laser). (auteurs)

  19. Measurement of the energy loss of heavy ions in laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Knobloch-Maas, Renate

    2009-11-25

    The interaction of ions with plasma is not yet fully understood today, although it is important for inertial fusion technology. During recent years, the energy loss of heavy ions in plasma has therefore been a subject of research in the Laser and Plasma Physics group of Darmstadt University of Technology. Several experiments were carried out at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt using laser-created plasma, thereby taking advantage of the unique combination of GSI's accelerator facility and the laser system nhelix, which is also described in this work. The experiments focus on the measurement of the energy loss of medium heavy ions in a plasma created by directly heating a thin carbon foil with the nhelix laser, at an energy of about 50 J. In order to measure the energy loss using a time-of-flight method, a stop detector is used to register the arrival of the ion pulses after passing the plasma and a 12 m drift space. At the beginning of the work on this thesis, the ion detector types formerly used were found to be inadequately suited to the difficult task; this was changed during this thesis. The ion detector has to be able to temporarily resolve ion pulses with a frequency of 108 MHz and a width (FWHM) of 3 ns at a very low current. It also has to withstand the X-ray burst from the plasma with a dead time shorter than the difference between the X-ray and the ion time of flight between the plasma and the detector. In order to satisfy these and other demands, a new diamond detector was designed and has now been used for several measurements. In addition to the new detector, other improvements were made concerning the diagnostics and the laser. The laser-created plasma now reaches a maximum temperature exceeding 200 eV and a free electron density of up to 10{sup 22} cm{sup -3}. With this greatly improved setup, energy loss data could be obtained with a temporal resolution several times better than before, using an ion beam with a

  20. Measurement of the energy loss of heavy ions in laser-produced plasmas

    International Nuclear Information System (INIS)

    Knobloch-Maas, Renate

    2009-01-01

    The interaction of ions with plasma is not yet fully understood today, although it is important for inertial fusion technology. During recent years, the energy loss of heavy ions in plasma has therefore been a subject of research in the Laser and Plasma Physics group of Darmstadt University of Technology. Several experiments were carried out at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt using laser-created plasma, thereby taking advantage of the unique combination of GSI's accelerator facility and the laser system nhelix, which is also described in this work. The experiments focus on the measurement of the energy loss of medium heavy ions in a plasma created by directly heating a thin carbon foil with the nhelix laser, at an energy of about 50 J. In order to measure the energy loss using a time-of-flight method, a stop detector is used to register the arrival of the ion pulses after passing the plasma and a 12 m drift space. At the beginning of the work on this thesis, the ion detector types formerly used were found to be inadequately suited to the difficult task; this was changed during this thesis. The ion detector has to be able to temporarily resolve ion pulses with a frequency of 108 MHz and a width (FWHM) of 3 ns at a very low current. It also has to withstand the X-ray burst from the plasma with a dead time shorter than the difference between the X-ray and the ion time of flight between the plasma and the detector. In order to satisfy these and other demands, a new diamond detector was designed and has now been used for several measurements. In addition to the new detector, other improvements were made concerning the diagnostics and the laser. The laser-created plasma now reaches a maximum temperature exceeding 200 eV and a free electron density of up to 10 22 cm -3 . With this greatly improved setup, energy loss data could be obtained with a temporal resolution several times better than before, using an ion beam with a diameter of only

  1. Genetic interrelations in the actinomycin biosynthetic gene clusters of Streptomyces antibioticus IMRU 3720 and Streptomyces chrysomallus ATCC11523, producers of actinomycin X and actinomycin C

    Directory of Open Access Journals (Sweden)

    Crnovčić I

    2017-04-01

    Full Text Available Ivana Crnovčić,1 Christian Rückert,2 Siamak Semsary,1 Manuel Lang,1 Jörn Kalinowski,2 Ullrich Keller1 1Institut für Chemie, Technische Universität Berlin, Berlin-Charlottenburg, 2Technology Platform Genomics, Center for Biotechnology, Bielefeld University, Bielefeld, Germany Abstract: Sequencing the actinomycin (acm biosynthetic gene cluster of Streptomyces antibioticus IMRU 3720, which produces actinomycin X (Acm X, revealed 20 genes organized into a highly similar framework as in the bi-armed acm C biosynthetic gene cluster of Streptomyces chrysomallus but without an attached additional extra arm of orthologues as in the latter. Curiously, the extra arm of the S. chrysomallus gene cluster turned out to perfectly match the single arm of the S. antibioticus gene cluster in the same order of orthologues including the the presence of two pseudogenes, scacmM and scacmN, encoding a cytochrome P450 and its ferredoxin, respectively. Orthologues of the latter genes were both missing in the principal arm of the S. chrysomallus acm C gene cluster. All orthologues of the extra arm showed a G +C-contents different from that of their counterparts in the principal arm. Moreover, the similarities of translation products from the extra arm were all higher to the corresponding translation products of orthologue genes from the S. antibioticus acm X gene cluster than to those encoded by the principal arm of their own gene cluster. This suggests that the duplicated structure of the S. chrysomallus acm C biosynthetic gene cluster evolved from previous fusion between two one-armed acm gene clusters each from a different genetic background. However, while scacmM and scacmN in the extra arm of the S. chrysomallus acm C gene cluster are mutated and therefore are non-functional, their orthologues saacmM and saacmN in the S. antibioticus acm C gene cluster show no defects seemingly encoding active enzymes with functions specific for Acm X biosynthesis. Both acm

  2. Neurokinin B-producing projection neurons in the lateral stripe of the striatum and cell clusters of the accumbens nucleus in the rat.

    Science.gov (United States)

    Zhou, Ligang; Furuta, Takahiro; Kaneko, Takeshi

    2004-12-06

    Neurons producing preprotachykinin B (PPTB), the precursor of neurokinin B, constitute 5% of neurons in the dorsal striatum and project to the substantia innominata (SI) selectively. In the ventral striatum, PPTB-producing neurons are collected mainly in the lateral stripe of the striatum (LSS) and cell clusters of the accumbens nucleus (Acb). In the present study, we first examined the distribution of PPTB-immunoreactive neurons in rat ventral striatum and found that a large part of the PPTB-immunoreactive cell clusters was continuous to the LSS, but a smaller part was not. Thus, we divided the PPTB-immunoreactive cell clusters into the LSS-associated and non-LSS-associated ones. We next investigated the projection targets of the PPTB-producing ventral striatal neurons by combining immunofluorescence labeling and retrograde tracing. After injection of Fluoro-Gold into the basal component of the SI (SIb) and medial part of the interstitial nucleus of posterior limb of the anterior commissure, many PPTB-immunoreactive neurons were retrogradely labeled in the LSS-associated cell clusters and LSS, respectively. When the injection site included the ventral part of the sublenticular component of the SI(SIsl), retrogradely labeled neurons showed PPTB-immunoreactivity frequently in non-LSS-associated cell clusters. Furthermore, these PPTB-immunoreactive projections were confirmed by the double-fluorescence method after anterograde tracer injection into the ventral striatum containing the cell clusters. Since the dorsalmost part of the SIsl is known to receive strong inputs from PPTB-producing dorsal striatal neurons, the present results indicate that PPTB-producing ventral striatal neurons project to basal forebrain target regions in parallel with dorsal striatal neurons without significant convergence. 2004 Wiley-Liss, Inc.

  3. 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.

  4. Chemical degradation of selected Zn-based corrosion products induced by C{sub 60} cluster, Ar cluster and Ar{sup +} ion sputtering in the focus of X-ray photoelectron spectroscopy (XPS)

    Energy Technology Data Exchange (ETDEWEB)

    Steinberger, R., E-mail: roland.steinberger@jku.at [Christian Doppler Laboratory for Microscopic and Spectroscopic Material Characterization, Center for Surface and Nanoanalytics, Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz (Austria); Sicking, J., E-mail: jens.sicking@bayer.com [Bayer AG, Engineering & Technology, Applied Physics, Chempark Building E 41, 51368 Leverkusen (Germany); Weise, J., E-mail: juliane.weise@physik.tu-freiberg.de [Institut für Experimentelle Physik, TU Bergakademie Freiberg, Leipziger Straße 23, 09599 Freiberg (Germany); Duchoslav, J., E-mail: jiri.duchoslav@jku.at [Christian Doppler Laboratory for Microscopic and Spectroscopic Material Characterization, Center for Surface and Nanoanalytics, Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz (Austria); Greunz, T., E-mail: theresia.greunz@jku.at [Christian Doppler Laboratory for Microscopic and Spectroscopic Material Characterization, Center for Surface and Nanoanalytics, Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz (Austria); Meyer, D.C., E-mail: Dirk-Carl.Meyer@physik.tu-freiberg.de [Institut für Experimentelle Physik, TU Bergakademie Freiberg, Leipziger Straße 23, 09599 Freiberg (Germany); Stifter, D., E-mail: david.stifter@jku.at [Christian Doppler Laboratory for Microscopic and Spectroscopic Material Characterization, Center for Surface and Nanoanalytics, Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz (Austria)

    2017-05-01

    Highlights: • XPS investigations for various sputter concepts on Zn-based corrosions products. • Direct comparison of induced chemical damage for ion and cluster sputtering. • Azimuthal rotation or heavy projectile bombardment was not found to be beneficial. • Ar cluster etching is rated as unsuitable for surface cleaning or depth profiling. • C{sub 60} and Ar{sup +} are applicable for sputtering when degradation is carefully considered. - Abstract: Monoatomic ion sputtering is a common concept for surface sensitive analysis methods to clean surfaces prior investigation or to obtain information from deeper regions. However, severe damage of the materials – linked to preferential sputtering, ion implantation, atomic mixing and in worst case chemical degradation – can affect the validity of the analysis. Hence, the impact of C{sub 60} cluster etching, furthermore, of Ar{sup +} ion bombardment with and without azimuthal sample rotation and also the application of heavy projectiles (Xe{sup +} ions) was investigated to find a concept, which is less destructive or with less critical influence on the chemical nature of the investigated materials. In this work the focus is set on hydrozincite and zinc oxide, two common corrosion products of Zn-based coatings. As a main point, all the obtained results from (i) Ar{sup +} ion, (ii) Ar cluster, and (iii) C{sub 60} cluster etching on the degradation kinetics of hydrozincite were compared with respect to the reached sputter depth. In addition, the sputter rate of all three methods was experimentally determined for ZnO. In total, fully non-destructive conditions could not be found, but valuable knowledge on the type and rate of degradation, which is essential to choose the most suited sputter concept.

  5. Characteristics and applications of ion streams produced by long-pulse lasers

    Czech Academy of Sciences Publication Activity Database

    Rohlena, Karel; Láska, Leoš; Jungwirth, Karel; Krása, Josef; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Ullschmied, Jiří; Badziak, J.; Parys, P.; Wolowski, J.; Gammino, S.; Torrisi, L.; Boody, F. P.

    2005-01-01

    Roč. 47, - (2005), B503-B512 ISSN 0741-3335. [EPS Plasma Physics Conference /32nd./. Tarragona, 27.06.2005-01.07.2005] R&D Projects: GA ČR(CZ) GA202/05/2475 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser plasma * ion sources * implantation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.902, year: 2005

  6. Wave number determination of Pc 1-2 mantle waves considering He++ ions: A Cluster study

    Science.gov (United States)

    Grison, B.; Escoubet, C. P.; Santolík, O.; Cornilleau-Wehrlin, N.; Khotyaintsev, Y.

    2014-09-01

    The present case study concerns narrowband electromagnetic emission detected in the distant cusp region simultaneously with upgoing plasma flows. The wave properties match the usual properties of the Pc 1-2 mantle waves: small angle between the wave vector and the magnetic field line, left-hand polarization, and propagation toward the ionosphere. We report here the first direct wave vector measurement of these waves (about 1.2 × 10- 2 rad/km) through multi spacecraft analysis using the three magnetic components and, at the same time, through single spacecraft analysis based on the refractive index analysis using the three magnetic components and two electric components. The refractive index analysis offers a simple way to estimate wave numbers in this frequency range. Numerical calculations are performed under the observed plasma conditions. The obtained results show that the ion distribution functions are unstable to ion cyclotron instability at the observed wave vector value, due to the large ion temperature anisotropy. We thus show that these electromagnetic ion cyclotron (EMIC) waves are amplified in the distant cusp region. The Poynting flux of the waves is counterstreaming with respect to the plasma flow. This sense of propagation is consistent with the time necessary to amplify the emissions to the observed level. We point out the role of the wave damping at the He++ gyrofrequency to explain that such waves cannot be observed from the ground at the cusp foot print location.

  7. Metallic oxide nano-clusters synthesis by ion implantation in high purity Fe10Cr alloy

    International Nuclear Information System (INIS)

    Zheng, Ce

    2015-01-01

    ODS (Oxide Dispersed Strengthened) steels, which are reinforced with metal dispersions of nano-oxides (based on Y, Ti and O elements), are promising materials for future nuclear reactors. The detailed understanding of the mechanisms involved in the precipitation of these nano-oxides would improve manufacturing and mechanical properties of these ODS steels, with a strong economic impact for their industrialization. To experimentally study these mechanisms, an analytical approach by ion implantation is used, to control various parameters of synthesis of these precipitates as the temperature and concentration. This study demonstrated the feasibility of this method and concerned the behaviour of alloys models (based on aluminium oxide) under thermal annealing. High purity Fe-10Cr alloys were implanted with Al and O ions at room temperature. Transmission electron microscopy observations showed that the nano-oxides appear in the Fe-10Cr matrix upon ion implantation at room temperature without subsequent annealing. The mobility of implanted elements is caused by the defects created during ion implantation, allowing the nucleation of these nanoparticles, of a few nm in diameter. These nanoparticles are composed of aluminium and oxygen, and also chromium. The high-resolution experiments show that their crystallographic structure is that of a non-equilibrium compound of aluminium oxide (cubic γ-Al 2 O 3 type). The heat treatment performed after implantation induces the growth of the nano-sized oxides, and a phase change that tends to balance to the equilibrium structure (hexagonal α-Al 2 O 3 type). These results on model alloys are fully applicable to industrial materials: indeed ion implantation reproduces the conditions of milling and heat treatments are at equivalent temperatures to those of thermo-mechanical treatments. A mechanism involving the precipitation of nano-oxide dispersed in ODS alloys is proposed in this manuscript based on the obtained experimental results

  8. Polymerization of solid C60 under C60 cluster ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vacík, Jiří; Naramoto, H.; Narumi, K.

    2009-01-01

    Roč. 95, - (2009), s. 867-873 ISSN 0947-8396 R&D Projects: GA AV ČR(CZ) KAN400480701; GA MŠk(CZ) LC06041 Institutional research plan: CEZ:AV0Z10480505 Keywords : fulleren * cluster * bombardment * polymerization Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.595, year: 2009 http://www.springerlink.com/content/0947-8396

  9. Cluster expansion of the solvation free energy difference: Systematic improvements in the solvation of single ions

    Science.gov (United States)

    Pliego, Josefredo R.

    2017-07-01

    The cluster expansion method has been used in the imperfect gas theory for several decades. This paper proposes a cluster expansion of the solvation free energy difference. This difference, which results from a change in the solute-solvent potential energy, can be written as the logarithm of a finite series. Similar to the Mayer function, the terms in the series are related to configurational integrals, which makes the integrand relevant only for configurations of the solvent molecules close to the solute. In addition, the terms involve interaction of solute with one, two, and so on solvent molecules. The approach could be used for hybrid quantum mechanical and molecular mechanics methods or mixed cluster-continuum approximation. A simple form of the theory was applied for prediction of pKa in methanol; the results indicated that three explicit methanol molecules and the dielectric continuum lead to a root of mean squared error (RMSE) of only 1.3 pKa units, whereas the pure continuum solvation model based on density method leads to a RMSE of 6.6 pKa units.

  10. submitter On the composition of ammonia–sulfuric-acid ion clusters during aerosol particle formation

    CERN Document Server

    Schobesberger, S; Bianchi, F; Rondo, L; Duplissy, J; Kürten, A; Ortega, I K; Metzger, A; Schnitzhofer, R; Almeida, J; Amorim, A; Dommen, J; Dunne, E M; Ehn, M; Gagné, S; Ickes, L; Junninen, H; Hansel, A; Kerminen, V -M; Kirkby, J; Kupc, A; Laaksonen, A; Lehtipalo, K; Mathot, S; Onnela, A; Petäjä, T; Riccobono, F; Santos, F D; Sipilä, M; Tomé, A; Tsagkogeorgas, G; Viisanen, Y; Wagner, P E; Wimmer, D; Curtius, J; Donahue, N M; Baltensperger, U; Kulmala, M; Worsnop, D R

    2015-01-01

    The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new-particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia $(NH_3)$ and sulfuric acid $(H-2SO_4)$. Experiments were conducted in the presence of water, ozone and sulfur dioxide. Contaminant trace gases were suppressed at the technological limit. For this study, we mapped out the compositions of small $NH_3–H_2SO_4$ clusters over a wide range of atmospherically relevant environmental conditions. We covered [NH3] in the range from 10. Positively charged clusters grew on average by Δm/Δn = 1.05 and were only observed at sufficiently high $[NH_3]$ / $[H_2SO_4]$. The $H_2SO_4$ molecules of these clusters are partially neutralized by $NH_3$, in close resemblance...

  11. Photoelectric work function measurement of a cesiated metal surface and its correlation with the surface-produced H- ion flux

    International Nuclear Information System (INIS)

    Wada, M.; Berkner, K.H.; Pyle, R.V.; Stearns, J.W.

    1982-09-01

    For application in plasma heating, fueling, and current drive of magnetic fusion devices, high current negative deuterium ion sources for intense neutral beam injectors are being developed using efficient production of negative hydrogen isotope ions on low work function metal surfaces imbedded in hydrogen plasmas. In order to investigate the correlation between work function and negative hydrogen ion production, photoelectron emission from a cesiated metal surface, which is immersed in a hydrogen plasma with an electron density less than 5 x 10 10 /cc, was measured in the photon energy range of 1.3 to 4.1 eV. The work function determination was based on Fowler's analysis, and at the optimum coverage a work function of less than 1.5 eV was observed for a Cs-Cu surface. Measured values of work functions for different Cs coverages were compared to the negative hydrogen currents produced at the metal surface in the discharge; the surface production of negative hydrogen ion current is monotonically increasing with decreasing work function

  12. Method of producing p-i-n structures by compensation of lithium ions from both side of silicon

    International Nuclear Information System (INIS)

    Muminov, R.A.; Radjapov, S.A.; Saymbetov, A.K.; Tursunkulov, O.M.; Pindurin, Yu.S.

    2007-01-01

    Full text: Semiconductor nuclear radiation detectors are needed to solve certain problems in nuclear spectroscopy. The development of efficiency detectors became possible with advances in growing high purify silicon single crystals with the required properties, satisfying the requirements for obtaining detectors based on them. One important requirement for obtaining detectors with sensitive area is that its resistance must be high. This is achieved by using the lithium ion drift process in the volume of the semiconductor detector. Thus it has been developed and created silicon semiconductor nuclear radiation detectors with vide range of diameter of sensitive area up to 100 mm and thickness (from 1mm to 10mm). At present work a new method for producing p-i-n structures was developed to decrease substantially the time required for compensation of silicon by lithium ions and to eliminate at the same time the negative consequences of holding the crystal at a high temperature and under a high voltage. Drift of lithium ions from two ends of prepared samples is conducted to a depth sufficient for the required compensation of the initial acceptor impurity in silicon. The method described above was used to fabricate a batch of Si(Li) detectors with a 1-10 mm thick and 10-110 mm in diameter sensitive region. The thickness of the sensitive region was determined by performing standard measurements and chemical pigmentation. Advantages of detectors are they have improved properties and less time for compensation of lithium ions. (authors)

  13. Energy dependence of the stopping power of MeV 16O ions in a laser-produced plasma

    International Nuclear Information System (INIS)

    Sakumi, A.; Shibata, K.; Sato, R.; Tsubuku, K.; Nishimoto, T.; Hasegawa, J.; Ogawa, M.; Oguri, Y.; Katayama, T.

    2001-01-01

    The energy dependence of the stopping power of 16 O ions in a laser-produced plasma target was experimentally investigated in the projectile energy range of 150-350 keV/u. In order to produce the target plasma a Q-Switched Nd-glass laser was focused onto a small lithium hydride (LiH) pellet. The plasma electron temperature and the electron line density were 15 eV and 2x10 17 cm -2 , respectively. The energy loss of 16 O ions in the plasma was measured by a time-of-flight (TOF) method. We found that the stopping power in the plasma agreed with the theoretical estimation based on a modified Bohr equation with correction at low velocities. In this evaluation, the effective charge of the projectile was calculated by means of rate equations on the loss and capture of electrons. It has been also found that in this projectile energy range the stopping power of the 16 O ions in the plasma still increases with decreasing projectile energy, while it decreases in cold equivalent

  14. Removal of Pb(II ions and malachite green dye from wastewater by activated carbon produced from lemon peel

    Directory of Open Access Journals (Sweden)

    Sayed Zia Mohammadi

    2014-06-01

    Full Text Available In the present study, a high-surface area activated carbon was prepared by chemical activation of lemon peel with H3PO4 as the active agent. Then, the adsorption behavior of Malachite green dye and Pb(II ions on the produced activated carbon was studied. Batch process was employed for sorption kinetics and equilibrium studies. Experimental data were �tted to various isotherm models. According to the Langmuir model, the maximum adsorption capacities of Malachite green dye and Pb(II ions were found to be 66.67 and 90.91 mg g-1, respectively, at room temperature. Kinetic studies showed the adsorption process followed a pseudo second-order rate model. The sorption kinetics were controlled by intra-particle diffusion. The results indicated that the produced activated carbon can be economically and effectively used as an adsorbent for the removal of Malachite green dye and Pb(II ions from wastewaters.

  15. "Trampoline" ejection of organic molecules from graphene and graphite via keV cluster ions impacts

    Science.gov (United States)

    Verkhoturov, Stanislav V.; Gołuński, Mikołaj; Verkhoturov, Dmitriy S.; Geng, Sheng; Postawa, Zbigniew; Schweikert, Emile A.

    2018-04-01

    We present the data on ejection of molecules and emission of molecular ions caused by single impacts of 50 keV C602+ on a molecular layer of deuterated phenylalanine (D8Phe) deposited on free standing, 2-layer graphene. The projectile impacts on the graphene side stimulate the abundant ejection of intact molecules and the emission of molecular ions in the transmission direction. To gain insight into the mechanism of ejection, Molecular Dynamic simulations were performed. It was found that the projectile penetrates the thin layer of graphene, partially depositing the projectile's kinetic energy, and molecules are ejected from the hot area around the hole that is made by the projectile. The yield, Y, of negative ions of deprotonated phenylalanine, (D8Phe-H)-, emitted in the transmission direction is 0.1 ions per projectile impact. To characterize the ejection and ionization of molecules, we have performed the experiments on emission of (D8Phe-H)- from the surface of bulk D8Phe (Y = 0.13) and from the single molecular layer of D8Phe deposited on bulk pyrolytic graphite (Y = 0.15). We show that, despite the similar yields of molecular ions, the scenario of the energy deposition and ejection of molecules is different for the case of graphene due to the confined volume of projectile-analyte interaction. The projectile impact on the graphene-D8Phe sample stimulates the collective radial movement of analyte atoms, which compresses the D8Phe layer radially from the hole. At the same time, this compression bends and stretches the graphene membrane around the hole thus accumulating potential energy. The accumulated potential energy is transformed into the kinetic energy of correlated movement upward for membrane atoms, thus the membrane acts as a trampoline for the molecules. The ejected molecules are effectively ionized; the ionization probability is ˜30× higher compared to that obtained for the bulk D8Phe target. The proposed mechanism of ionization involves tunneling of

  16. "Trampoline" ejection of organic molecules from graphene and graphite via keV cluster ions impacts.

    Science.gov (United States)

    Verkhoturov, Stanislav V; Gołuński, Mikołaj; Verkhoturov, Dmitriy S; Geng, Sheng; Postawa, Zbigniew; Schweikert, Emile A

    2018-04-14

    We present the data on ejection of molecules and emission of molecular ions caused by single impacts of 50 keV C 60 2+ on a molecular layer of deuterated phenylalanine (D8Phe) deposited on free standing, 2-layer graphene. The projectile impacts on the graphene side stimulate the abundant ejection of intact molecules and the emission of molecular ions in the transmission direction. To gain insight into the mechanism of ejection, Molecular Dynamic simulations were performed. It was found that the projectile penetrates the thin layer of graphene, partially depositing the projectile's kinetic energy, and molecules are ejected from the hot area around the hole that is made by the projectile. The yield, Y, of negative ions of deprotonated phenylalanine, (D8Phe-H) - , emitted in the transmission direction is 0.1 ions per projectile impact. To characterize the ejection and ionization of molecules, we have performed the experiments on emission of (D8Phe-H) - from the surface of bulk D8Phe (Y = 0.13) and from the single molecular layer of D8Phe deposited on bulk pyrolytic graphite (Y = 0.15). We show that, despite the similar yields of molecular ions, the scenario of the energy deposition and ejection of molecules is different for the case of graphene due to the confined volume of projectile-analyte interaction. The projectile impact on the graphene-D8Phe sample stimulates the collective radial movement of analyte atoms, which compresses the D8Phe layer radially from the hole. At the same time, this compression bends and stretches the graphene membrane around the hole thus accumulating potential energy. The accumulated potential energy is transformed into the kinetic energy of correlated movement upward for membrane atoms, thus the membrane acts as a trampoline for the molecules. The ejected molecules are effectively ionized; the ionization probability is ∼30× higher compared to that obtained for the bulk D8Phe target. The proposed mechanism of ionization involves

  17. Lifetime and quenching of CO /a super 3 pi/ produced by recombination of CO2 ions in a helium afterglow.

    Science.gov (United States)

    Wauchop, T. S.; Broida, H. P.

    1972-01-01

    Demonstration that rapid dissociative recombination of CO2(+) in a flowing, helium afterglow is an efficient source of CO in the a super 3 pi metastable state. Ions produced by mixing CO2 with He(2 super 3 S) recombine to produce a CO metastable afterglow with a number density as great as 10 to the 9th per sq cm. Monitoring of the (a super 3 pi-X super 1 sigma) Cameron transition in CO was used to study the lifetime and quenching of CO (a super 3 pi) by CO2, N2, NO, and He. Recombination of CO2(+) also produces CO in the d super 3 delta and a' super 3 sigma states.

  18. Can pions created in high-energy heavy-ion collisions produce a Centauro-type effect?

    International Nuclear Information System (INIS)

    Martinis, M.; Mikuta-Martinis, V.; Crnugelj, J.

    1995-01-01

    We study a Centauro-type phenomenon in high-energy heavy-ion collisions by assuming that pions are produced semiclassically both directly and in pairs through the isovector channel. The leading-particle effect and the factorization property of the scattering amplitude in the impact-parameter space are used to define the classical pion field. We show that the Centauro-type effect is strongly suppressed if a large number of pions are produced in isovector pairs. Our conclusion is supported through the calculation of two pion correlation parameters, f 2 0- and f 2 00 , as well as f 2, n - 0 and the average number of neutral pions (left-angle n 0 right-angle n- ) a a function of negative pions (n - ) produced

  19. Ridge optical waveguide in an Er3+/Yb3+ co-doped phosphate glass produced by He+ ion implantation combined with Ar+ ion beam etching

    International Nuclear Information System (INIS)

    Tan Yang; Chen Feng; Hu Lili; Xing Pengfei; Chen Yanxue; Wang Xuelin; Wang Keming

    2007-01-01

    This paper reports on the fabrication and characterization of a ridge optical waveguide in an Er 3+ /Yb 3+ co-doped phosphate glass. The He + ion implantation (at energy of 2.8 MeV) is first applied onto the sample to produce a planar waveguide substrate, and then Ar + ion beam etching (at energy of 500 eV) is carried out to construct rib stripes on the sample surface that has been deposited by a specially designed photoresist mask. According to a reconstructed refractive index profile of the waveguide cross section, the modal distribution of the waveguide is simulated by applying a computer code based on the beam propagation method, which shows reasonable agreement with the experimentally observed waveguide mode by using the end-face coupling method. Simulation of the incident He ions at 2.8 MeV penetrating into the Er 3+ /Yb 3+ co-doped phosphate glass substrate is also performed to provide helpful information on waveguide formation

  20. Operation modes of the FALCON ion source as a part of the AMS cluster tool

    Directory of Open Access Journals (Sweden)

    Girka Oleksii

    2015-06-01

    Full Text Available The paper investigates the options to increase the production yield of temperature compensated surface acoustic wave (SAW devices with a defined range of operational frequencies. The paper focuses on the preparation of large wafers with SiO2 and AlN/Si3N4 depositions. Stability of the intermediate SiO2 layer is achieved by combining high power density UV radiation with annealing in high humidity environment. A uniform thickness of the capping AlN layer is achieved by local high-rate etching with a focused ion beam emitted by the FALCON ion source. Operation parameters and limitations of the etching process are discussed.

  1. Study on breeding of daptomycin-producing strains by nitrogen ion implantation

    International Nuclear Information System (INIS)

    Zhou Jian; Liu Ying; Fang Dongsheng; Jiang Hong; Zhang Yin; Gao Wuyan

    2008-01-01

    Streptomyces roseosporus C20, the bacteria used in production of daptomycin, were implanted with (15-200)x10 13 /cm 2 of 20keV N + ions. Survival rate of the bacteria at different absorbed doses was investigated, and mutagenic effects of the microbe were studied. After breeding under the selection pressure of resistance to streptomycin (the lethal concentration is 1.2μg/mL), several mutant strains with higher yields of daptomycin have been obtained. One of mutant strains, N3-36, can increase up to 126% compared to the original strain. It also shows that the mutant strains have high genetic stability. (authors)

  2. An explosive-emitter cathode produced using the heavy ion track technique

    International Nuclear Information System (INIS)

    Akap'ev, G.N.; Korenev, S.A.

    1988-01-01

    A cathode based on thin metallic foils with a homogeneous needle surface is described. The cathode was manufactured using the heavy ion track technique which permits the production of cathodes with an unlimited area and a needle density ranging from about 10 3 to 10 9 needles per cm 2 . An electron gun using this type of cathode has a current of 200-900 A and an energy of 100-300 keV. The cross section of the electron beam is fairly uniform. It is shown that needle emitters of similar shape and size play the principal role in forming a homogeneous cathode plasma

  3. 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.

  4. Lead-silicate glass surface sputtered by an argon cluster ion beam investigated by XPS

    Czech Academy of Sciences Publication Activity Database

    Zemek, Josef; Jiříček, Petr; Houdková, Jana; Jurek, Karel; Gedeon, O.

    2017-01-01

    Roč. 469, Aug (2017), s. 1-6 ISSN 0022-3093 R&D Projects: GA MŠk LM2015088; GA ČR(CZ) GA15-12580S Institutional support: RVO:68378271 Keywords : lead-silicate glass * XPS * BO * NBO * Argon duster ion beam sputtering * X-ray irradiation Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.124, year: 2016

  5. Structure, properties and applications of TiN coatings produced by sputter ion plating

    International Nuclear Information System (INIS)

    Rickerby, D.S.

    1988-01-01

    The potential beneficial effects that wear-resistant coatings have on engineering surfaces depends upon their ability to remain adherent with the treated component. This paper concentrates on the process of sputter ion plating, a simple dc glow discharge sputtering system operating in soft vacuum, and relates the properties of titanium nitride coatings to the degree of ion polishing (substrate bias) which is utilised during deposition. Substrate bias was identified as the most important system parameter since it allowed for some stress relaxation within the coating via its influence on porosity levels in the coating microstructure. The influence that this has on coating adhesion is discussed. The internal stress is a combination of intrinsic growth stresses and thermal mismatch stresses with the latter tending to dominate as substrate bias is increased. In addition to substrate bias, the role that titanium interlayers and substrate cleaning play in improving the adhesion of titanium nitride coatings is discussed, and the potential benefits highlighted. In the last part of the paper some applications of titanium nitride coating are described -it will be shown that increase in component life is by no means the only criterion which should be considered when judging the success, or otherwise, of a coated component. (author)

  6. [Search for strange quark matter and antimatter produced in high energy heavy ion collisions

    International Nuclear Information System (INIS)

    1992-01-01

    This document describes the development and progress of our group's research program in high energy heavy ion physics. We are a subset of the Yale experimental high energy physics effort (YAUG group) who became interested in the physics of high energy heavy ions in 1988. Our interest began with the possibility of performing significant searches for strange quark matter. As we learned more about the subject and as we gained experimental experience through our participation in AGS experiment 814, our interests have broadened. Our program has focused on the study of new particles, including (but not exclusively) strange quark matter, and the high sensitivity measurement of other composite nuclear systems such as antinuclei and various light nuclei. The importance of measurements of the known, but rare, nuclear systems lies in the study of production mechanisms. A good understanding of the physics and phenomenology of rare composite particle production in essential for the interpretation of limits to strange quark matter searches. We believe that such studies will also be useful in probing the mechanisms involved in the collision process itself. We have been involved in the running and data analysis for AGS E814. We have also worked on the R ampersand D for AGS E864, which is an approved experiment designed to reach sensitivities where there will be a good chance of discovering strangelets or of setting significant limits on the parameters of strange quark matter

  7. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    Science.gov (United States)

    Oganessian, Yu. Ts.; Shchepunov, V. A.; Dmitriev, S. N.; Itkis, M. G.; Gulbekyan, G. G.; Khabarov, M. V.; Bekhterev, V. V.; Bogomolov, S. L.; Efremov, A. A.; Pashenko, S. V.; Stepantsov, S. V.; Yeremin, A. V.; Yavor, M. I.; Kalimov, A. G.

    2003-05-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10 -3. The set up can work in the wide mass range from A≈20 to A≈500, its mass acceptance is as large as ±2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90° electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considered. Description of its elements and subsystems is given.

  8. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    CERN Document Server

    Oganessian, Yu T; Dmitriev, S N; Itkis, M G; Gulbekyan, G G; Khabarov, M V; Bekhterev, V V; Bogomolov, S L; Efremov, A A; Pashenko, S V; Stepantsov, S V; Yeremin, A V; Yavor, M I; Kalimov, A G

    2003-01-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10 sup - sup 3. The set up can work in the wide mass range from A approx 20 to A approx 500, its mass acceptance is as large as +-2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90 deg. electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considere...

  9. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    International Nuclear Information System (INIS)

    Oganessian, Yu.Ts.; Shchepunov, V.A.; Dmitriev, S.N.; Itkis, M.G.; Gulbekyan, G.G.; Khabarov, M.V.; Bekhterev, V.V.; Bogomolov, S.L.; Efremov, A.A.; Pashenko, S.V.; Stepantsov, S.V.; Yeremin, A.V.; Yavor, M.I.; Kalimov, A.G.

    2003-01-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10 -3 . The set up can work in the wide mass range from A∼20 to A∼500, its mass acceptance is as large as ±2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90 deg. electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considered. Description of its elements and subsystems is given

  10. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    Energy Technology Data Exchange (ETDEWEB)

    Oganessian, Yu.Ts.; Shchepunov, V.A. E-mail: shchepun@sunhe.jinr.rushchepun@cv.jinr.ru; Dmitriev, S.N.; Itkis, M.G.; Gulbekyan, G.G.; Khabarov, M.V.; Bekhterev, V.V.; Bogomolov, S.L.; Efremov, A.A.; Pashenko, S.V.; Stepantsov, S.V.; Yeremin, A.V.; Yavor, M.I.; Kalimov, A.G

    2003-05-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10{sup -3}. The set up can work in the wide mass range from A{approx}20 to A{approx}500, its mass acceptance is as large as {+-}2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90 deg. electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considered. Description of its elements and subsystems is given.

  11. Development and test of ion emitter modules for the projects ASPOC/CLUSTER (8th project year) and EQUATOR-S (4th project year). Final report

    International Nuclear Information System (INIS)

    Fehringer, H.M.; Ruedenauer, F.G.; Steiger, W.

    1997-02-01

    Not only was the failure of flight V001 of the newly developed ARIANE-V rocket a disaster for the European space industry and a drawback in the highly competitive launcher business, with the loss of its payload, ESA's 4 scientific CLUSTER satellites, also the work and expectations of hundreds of scientists and engineers were buried in the swamps of French Guyana. The Austrian experiment ASPOC, for which ion emitters have been developed under the contract reported here, was one of the 12 instruments onboard. In a meeting following the launch failure ESA's Science Policy Committee (SPC) decided to immediately rebuild one CLUSTER satellite and use the instrument spare models as the payload. This new mission was called PHOENIX. Furthermore, the SPC initiated studies to look for options of a CLUSTER reflight. The final decision about the future of the CLUSTER project is now due in February 1997. Since ASPOC has been lost, this report only very shortly deals with the work done up to the launch date. More important are two aspects: First, the ion emitters, the product which has been developed within this long term project, are of such high quality that they survived both the explosion of the rocket and the subsequent free fall from 3.6 km height. Ten ion emitters have been recovered from the debris and all of them were still working well. Second, new applications both in the scientific and in the commercial area have been found for the indium ion sources. Under an ESA contract their potential use as ion thrusters has recently successfully been studied. A further contract now has been placed for the development of a prototype ion thruster. Furthermore, the indium ion source has been selected as the primary ion emitter for the time of flight mass spectrometer COSIMA, a key instrument of the ROSETTA mission. Concerning EQUATOR-S, a new set of ion emitter modules has to be built, as those originally foreseen for EQUATOR-S are now being used for PHOENIX. The respective

  12. Structural Characterizations of Palladium Clusters Prepared by Polyol Reduction of [PdCl4]2− Ions

    Directory of Open Access Journals (Sweden)

    Loredana Schiavo

    2016-01-01

    Full Text Available Palladium nanoparticles are of great interest in many industrial fields, ranging from catalysis and hydrogen technology to microelectronics, thanks to their unique physical and chemical properties. In this work, palladium clusters have been prepared by reduction of [PdCl4]2− ions with ethylene glycol, in the presence of poly(N-vinyl-2-pyrrolidone (PVP as stabilizer. The stabilizer performs the important role of nucleating agent for the Pd atoms with a fast phase separation, since palladium atoms coordinated to the polymer side-groups are forced at short distances during nucleation. Quasispherical palladium clusters with a diameter of ca. 2.6 nm were obtained by reaction in air at 90°C for 2 hours. An extensive materials characterization by transmission electron microscopy (TEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and other characterizations (TGA, SEM, EDS-SEM, and UV-Vis has been performed in order to evaluate the structure and oxidation state of nanopalladium.

  13. Effects of incident energy and angle on carbon cluster ions implantation on silicon substrate: a molecular dynamics study

    Science.gov (United States)

    Wei, Ye; Sang, Shengbo; Zhou, Bing; Deng, Xiao; Chai, Jing; Ji, Jianlong; Ge, Yang; Huo, Yuanliang; Zhang, Wendong

    2017-09-01

    Carbon cluster ion implantation is an important technique in fabricating functional devices at micro/nanoscale. In this work, a numerical model is constructed for implantation and implemented with a cutting-edge molecular dynamics method. A series of simulations with varying incident energies and incident angles is performed for incidence on silicon substrate and correlated effects are compared in detail. Meanwhile, the behavior of the cluster during implantation is also examined under elevated temperatures. By mapping the nanoscopic morphology with variable parameters, numerical formalism is proposed to explain the different impacts on phrase transition and surface pattern formation. Particularly, implantation efficiency (IE) is computed and further used to evaluate the performance of the overall process. The calculated results could be properly adopted as the theoretical basis for designing nano-structures and adjusting devices’ properties. Project supported by the National Natural Science Foundation of China (Nos. 51622507, 61471255, 61474079, 61403273, 51502193, 51205273), the Natural Science Foundation of Shanxi (Nos. 201601D021057, 201603D421035), the Youth Foundation Project of Shanxi Province (Nos. 2015021097), the Doctoral Fund of MOE of China (No. 20131402110013), the National High Technology Research and Development Program of China (No. 2015AA042601), and the Specialized Project in Public Welfare from The Ministry of Water Resources of China (Nos. 1261530110110).

  14. Role of isolated and clustered DNA damage and the post-irradiating repair process in the effects of heavy ion beam irradiation

    International Nuclear Information System (INIS)

    Tokuyama, Yuka; Terato, Hiroaki; Furusawa, Yoshiya; Ide, Hiroshi; Yasui, Akira

    2015-01-01

    Clustered DNA damage is a specific type of DNA damage induced by ionizing radiation. Any type of ionizing radiation traverses the target DNA molecule as a beam, inducing damage along its track. Our previous study showed that clustered DNA damage yields decreased with increased linear energy transfer (LET), leading us to investigate the importance of clustered DNA damage in the biological effects of heavy ion beam radiation. In this study, we analyzed the yield of clustered base damage (comprising multiple base lesions) in cultured cells irradiated with various heavy ion beams, and investigated isolated base damage and the repair process in post-irradiation cultured cells. Chinese hamster ovary (CHO) cells were irradiated by carbon, silicon, argon and iron ion beams with LETs of 13, 55, 90 and 200 keV µm -1 , respectively. Agarose gel electrophoresis of the cells with enzymatic treatments indicated that clustered base damage yields decreased as the LET increased. The aldehyde reactive probe procedure showed that isolated base damage yields in the irradiated cells followed the same pattern. To analyze the cellular base damage process, clustered DNA damage repair was investigated using DNA repair mutant cells. DNA double-strand breaks accumulated in CHO mutant cells lacking Xrcc1 after irradiation, and the cell viability decreased. On the other hand, mouse embryonic fibroblast (Mef) cells lacking both Nth1 and Ogg1 became more resistant than the wild type Mef. Thus, clustered base damage seems to be involved in the expression of heavy ion beam biological effects via the repair process. (author)

  15. Resonant ion-dip infrared spectroscopy of benzene-(water)n-(methanol)m clusters with n+m=4, 5

    International Nuclear Information System (INIS)

    Hagemeister, F.C.; Gruenloh, C.J.; Zwier, T.S.

    1998-01-01

    Resonant two-photon ionization and resonant ion-dip infrared (RIDIR) spectra of benzene-(water) n -(methanol) m clusters (hereafter shortened to BW n M m ) have been recorded for a total of seven clusters with n+m=4 and 5. The infrared spectra in the OH and CH stretch regions show absorptions characteristic of H-bonded W n M m clusters which are bound to benzene by a π H-bond involving a dangling OH on the W n M m sub-unit. Density functional theory (DFT) calculations identify a number of conformational isomers in the n+m=4 series which meet the general criteria imposed by the experimental spectra. The structures, binding energies, harmonic vibrational frequencies, and infrared intensities for these isomers have been calculated for comparison with experiment. Based on the calculations, tentative assignments of several of the observed species are given. The calculations uncover the fact that complexation of benzene to the cyclic water tetramer imposes much the same perturbations on the cycle as substitution of methanol for water. In particular, the single-donor OH stretch spectra of W n M m and BW n+1 M m-1 are calculated to be virtually identical to one another. The comparison of experiment and theory for this series of cyclic structures is used to assess the strengths and limitations of the calculations at the DFT Becke3LYP/6-31+G * level of theory. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  16. Interaction of nanosecond laser pulse with tetramethyl silane (Si(CH34 clusters: Generation of multiply charged silicon and carbon ions

    Directory of Open Access Journals (Sweden)

    Purav M. Badani

    2011-12-01

    Full Text Available Present work reports significantly high levels of ionization, eventually leading to Coulomb explosion of Tetramethyl silane (TMS clusters, on interaction with laser pulses of intensity ∼109 W/cm2. Tetramethyl silane clusters, prepared by supersonic expansion were photoionized at 266, 355 or 532 nm and the resultant ions were detected using time-of-flight mass spectrometer. It is observed that wavelength of irradiation and the size of the cluster are crucial parameters which drastically affect the nature of charge species generated upon photoionization of cluster. The results show that clusters absorb significantly higher energy from the laser field at longer wavelengths (532 nm and generate multiply charged silicon and carbon ions which have large kinetic energies. Further, laser-cluster interaction at different wavelengths has been quantified and charge densities at 266, 355 and 532 nm are found to be 4x 1010, 5x 1010 and 5x 1011 charges/cm3 respectively. These unusual results have been rationalized based on dominance of secondary ionization processes at 532 nm ultimately leading to Coulomb explosion of clusters. In another set of experiments, multiply charged ions of Ar (up to +5 state and Kr (up to +6 state were observed when TMS doped inert gas clusters were photoionized at 532 and 355 nm. The extent of energy absorption at these two wavelengths is clearly manifested from the charge state of the atomic ions generated upon Coulomb disintegration of the doped cluster. These experiments thus demonstrate a novel method for generation of multiply charged atomic ions of inert gases at laser intensity of ∼ 109 W/cm2. The average size of the cluster exhibiting Coulomb explosion phenomena under giga watt intensity conditions has been estimated to be ∼ 6 nm. Experimental results obtained in the present work agree qualitatively with the model proposed earlier [D. Niu, H. Li, F. Liang, L. Wen, X. Luo, B. Wang, and H. Qu, J. Chem. Phys. 122, 151103

  17. Molecular depth profiling of multi-layer systems with cluster ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Juan [Department of Chemistry, Penn State University, University Park, PA 16802 (United States); Winograd, Nicholas [Department of Chemistry, Penn State University, University Park, PA 16802 (United States)]. E-mail: nxw@psu.edu

    2006-07-30

    Cluster bombardment of molecular films has created new opportunities for SIMS research. To more quantitatively examine the interaction of cluster beams with organic materials, we have developed a reproducible platform consisting of a well-defined sugar film (trehalose) doped with peptides. Molecular depth profiles have been acquired with these systems using C{sub 60} {sup +} bombardment. In this study, we utilize this platform to determine the feasibility of examining buried interfaces for multi-layer systems. Using C{sub 60} {sup +} at 20 keV, several systems have been tested including Al/trehalose/Si, Al/trehalose/Al/Si, Ag/trehalose/Si and ice/trehalose/Si. The results show that there can be interactions between the layers during the bombardment process that prevent a simple interpretation of the depth profile. We find so far that the best results are obtained when the mass of the overlayer atoms is less than or nearly equal to the mass of the atoms in buried molecules. In general, these observations suggest that C{sub 60} {sup +} bombardment can be successfully applied to interface characterization of multi-layer systems if the systems are carefully chosen.

  18. Electrochemical characterization of silicon/graphene/MWCNT hybrid lithium-ion battery anodes produced via RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Toçoğlu, Ubeyd, E-mail: utocoglu@sakarya.edu.tr; Hatipoğlu, Gizem; Alaf, Miraç; Kayış, Fuat; Akbulut, Hatem

    2016-12-15

    Graphical abstract: Silicon/graphene/MWCNT hybrid composite anodes were produced via RF magnetron sputtering technique. CR2016 type coin cells were assembled for electrochemical characterization of anodes. Electrochemical characterizations of anodes were conducted via galvanostatic charge/discharge, cyclic voltammetry and electrochemical impedance spectroscopy techniques. - Highlights: • Silicon/graphene/MWCNT hybrid negative lithium ion battery anodes were produced via magnetron sputtering. • Structural and electrochemical characterizations of composite anodes were conducted comprehensively. • The capacity values exhibited by composite anodes were found to be almost more than two times compared to thin film anodes after 100 cycles. - Abstract: In this study it was aimed to enhance cycling performance of silicon lithium ion battery anodes via producing flexible Silicon/Graphene/MWCNT composite structures. The volumetric expansions, which are the primary obstacle that hinders the practical usage of silicon anodes, were tried to suppress using flexible graphene/MWCNT paper substrates. Moreover to achieve lightweight and high electrical conductive anodes, the advantage of graphene was aimed to be exploited. Silicon/graphene/MWCNT flexible composite anodes were produced via radio frequency (RF) magnetron sputtering technique. Graphene/MWCNT papers were produced with vacuum filtration technique as substrate for sputtering process. At coating process of papers constant sputtering power was applied. Phase analysis was conducted with X-ray diffraction (XRD) technique and Raman spectroscopy. Field emission scanning electron microscopy (FESEM). Cyclic voltammetry (CV) tests were carried out to reveal reversible reactions between silicon and lithium. Galvanostatic charge/discharge technique was employed to determine the cyclic performance of anodes. Electrochemical impedance spectroscopy technique was used to understand the relation between cyclic performance and

  19. Electrochemical characterization of silicon/graphene/MWCNT hybrid lithium-ion battery anodes produced via RF magnetron sputtering

    International Nuclear Information System (INIS)

    Toçoğlu, Ubeyd; Hatipoğlu, Gizem; Alaf, Miraç; Kayış, Fuat; Akbulut, Hatem

    2016-01-01

    Graphical abstract: Silicon/graphene/MWCNT hybrid composite anodes were produced via RF magnetron sputtering technique. CR2016 type coin cells were assembled for electrochemical characterization of anodes. Electrochemical characterizations of anodes were conducted via galvanostatic charge/discharge, cyclic voltammetry and electrochemical impedance spectroscopy techniques. - Highlights: • Silicon/graphene/MWCNT hybrid negative lithium ion battery anodes were produced via magnetron sputtering. • Structural and electrochemical characterizations of composite anodes were conducted comprehensively. • The capacity values exhibited by composite anodes were found to be almost more than two times compared to thin film anodes after 100 cycles. - Abstract: In this study it was aimed to enhance cycling performance of silicon lithium ion battery anodes via producing flexible Silicon/Graphene/MWCNT composite structures. The volumetric expansions, which are the primary obstacle that hinders the practical usage of silicon anodes, were tried to suppress using flexible graphene/MWCNT paper substrates. Moreover to achieve lightweight and high electrical conductive anodes, the advantage of graphene was aimed to be exploited. Silicon/graphene/MWCNT flexible composite anodes were produced via radio frequency (RF) magnetron sputtering technique. Graphene/MWCNT papers were produced with vacuum filtration technique as substrate for sputtering process. At coating process of papers constant sputtering power was applied. Phase analysis was conducted with X-ray diffraction (XRD) technique and Raman spectroscopy. Field emission scanning electron microscopy (FESEM). Cyclic voltammetry (CV) tests were carried out to reveal reversible reactions between silicon and lithium. Galvanostatic charge/discharge technique was employed to determine the cyclic performance of anodes. Electrochemical impedance spectroscopy technique was used to understand the relation between cyclic performance and

  20. Identification and functional analysis of gene cluster involvement in biosynthesis of the cyclic lipopeptide antibiotic pelgipeptin produced by Paenibacillus elgii

    Directory of Open Access Journals (Sweden)

    Qian Chao-Dong

    2012-09-01

    Full Text Available Abstract Background Pelgipeptin, a potent antibacterial and antifungal agent, is a non-ribosomally synthesised lipopeptide antibiotic. This compound consists of a β-hydroxy fatty acid and nine amino acids. To date, there is no information about its biosynthetic pathway. Results A potential pelgipeptin synthetase gene cluster (plp was identified from Paenibacillus elgii B69 through genome analysis. The gene cluster spans 40.8 kb with eight open reading frames. Among the genes in this cluster, three large genes, plpD, plpE, and plpF, were shown to encode non-ribosomal peptide synthetases (NRPSs, with one, seven, and one module(s, respectively. Bioinformatic analysis of the substrate specificity of all nine adenylation domains indicated that the sequence of the NRPS modules is well collinear with the order of amino acids in pelgipeptin. Additional biochemical analysis of four recombinant adenylation domains (PlpD A1, PlpE A1, PlpE A3, and PlpF A1 provided further evidence that the plp gene cluster involved in pelgipeptin biosynthesis. Conclusions In this study, a gene cluster (plp responsible for the biosynthesis of pelgipeptin was identified from the genome sequence of Paenibacillus elgii B69. The identification of the plp gene cluster provides an opportunity to develop novel lipopeptide antibiotics by genetic engineering.

  1. Contribution to the source size study produced in the heavy ion reactions at 30MeV/u

    International Nuclear Information System (INIS)

    Khelfaoui, Ben Abed.

    1991-05-01

    In this work are given the measurement results of source sizes produced in the heavy ion reactions at intermediate energies, and are studied the correlations of light particles (proton-proton correlations) with very weak momentum. The used technics is an application of intensity interferometry to the case of particles submitted to hadronic interactions. The studied reactions were induced by a 20 We beam on 12 C, 59 Co, and 197 Au targets at 25 0 C and on 27 Al (at 22 0 C, 60 0 C and 80 0 C). Beam energy was 30 MeV/u [fr

  2. Interaction between rare-earth ions and amorphous silicon nanoclusters produced at low processing temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Meldrum, A. [Department of Physics, University of Alberta, Edmonton, T6G2J1 (Canada)]. E-mail: ameldrum@ualberta.ca; Hryciw, A. [Department of Physics, University of Alberta, Edmonton, T6G2J1 (Canada); MacDonald, A.N. [Department of Physics, University of Alberta, Edmonton, T6G2J1 (Canada); Blois, C. [Department of Physics, University of Alberta, Edmonton, T6G2J1 (Canada); Clement, T. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, T6G2V4 (Canada); De Corby, R. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, T6G2V4 (Canada); Wang, J. [Department of Physics, Chinese University of Hong Kong, Shatin, Hong Kong (China); Li Quan [Department of Physics, Chinese University of Hong Kong, Shatin, Hong Kong (China)

    2006-12-15

    Temperatures of 1000 deg. C and higher are a significant problem for the incorporation of erbium-doped silicon nanocrystal devices into standard silicon technology, and make the fabrication of contacts and reflectors in light emitting devices difficult. In the present work, we use energy-filtered TEM imaging techniques to show the formation of size-controlled amorphous silicon nanoclusters in SiO films annealed between 400 and 500 deg. C. The PL properties of such films are characteristic of amorphous silicon, and the spectrum can be controlled via a statistical size effect-as opposed to quantum confinement-that has previously been proposed for porous amorphous silicon. Finally, we show that amorphous nanoclusters sensitize the luminescence from the rare-earth ions Er, Nd, Yb, and Tm with excitation cross-sections similar in magnitude to erbium-doped silicon nanocrystal composites, and with a similar nonresonant energy transfer mechanism.

  3. Does Aerobic Respiration Produce Carbon Dioxide or Hydrogen Ion and Bicarbonate?

    Science.gov (United States)

    Swenson, Erik R

    2018-05-01

    Maintenance of intracellular pH is critical for clinical homeostasis. The metabolism of glucose, fatty acids, and amino acids yielding the generation of adenosine triphosphate in the mitochondria is accompanied by the production of acid in the Krebs cycle. Both the nature of this acidosis and the mechanism of its disposal have been argued by two investigators with a long-abiding interest in acid-base physiology. They offer different interpretations and views of the molecular mechanism of this intracellular pH regulation during normal metabolism. Dr. John Severinghaus has posited that hydrogen ion and bicarbonate are the direct end products in the Krebs cycle. In the late 1960s, he showed in brain and brain homogenate experiments that acetazolamide, a carbonic anhydrase inhibitor, reduces intracellular pH. This led him to conclude that hydrogen ion and bicarbonate are the end products, and the role of intracellular carbonic anhydrase is to rapidly generate diffusible carbon dioxide to minimize acidosis. Dr. Erik Swenson posits that carbon dioxide is a direct end product in the Krebs cycle, a more widely accepted view, and that acetazolamide prevents rapid intracellular bicarbonate formation, which can then codiffuse with carbon dioxide to the cell surface and there be reconverted for exit from the cell. Loss of this "facilitated diffusion of carbon dioxide" leads to intracellular acidosis as the still appreciable uncatalyzed rate of carbon dioxide hydration generates more protons. This review summarizes the available evidence and determines that resolution of this question will require more sophisticated measurements of intracellular pH with faster temporal resolution.

  4. Formation of positive cluster ions Li(n) Br (n = 2-7) and ionization energies studied by thermal ionization mass spectrometry.

    Science.gov (United States)

    Veličković, S R; Đustebek, J B; Veljković, F M; Veljković, M V

    2012-05-01

    Clusters of the type Li(n)X (X = halides) can be considered as potential building blocks of cluster-assembly materials. In this work, Li(n)Br (n = 2-7) clusters were obtained by a thermal ionization source of modified design and selected by a magnetic sector mass spectrometer. Positive ions of the Li(n)Br (n = 4-7) cluster were detected for the first time. The order of ion intensities was Li(2)Br(+) > Li(4)Br(+) > Li(5)Br(+) > Li(6)Br(+) > Li(3)Br(+). The ionization energies (IEs) were measured and found to be 3.95 ± 0.20 eV for Li(2)Br, 3.92 ± 0.20 eV for Li(3)Br, 3.93 ± 0.20 eV for Li(4)Br, 4.08 ± 0.20 eV for Li(5)Br, 4.14 ± 0.20 eV for Li(6)Br and 4.19 ± 0.20 eV for Li(7)Br. All of these clusters have a much lower ionization potential than that of the lithium atom, so they belong to the superalkali class. The IEs of Li(n)Br (n = 2-4) are slightly lower than those in the corresponding small Li(n) or Li(n)H clusters, whereas the IEs of Li(n)Br are very similar to those of Li(n) or Li(n)H for n = 5 and 6. The thermal ionization source of modified design is an important means for simultaneously obtaining and measuring the IEs of Li(n)Br (n = 2-7) clusters (because their ions are hermodynamically stable with respect to the loss of lithium atoms in the gas phase) and increasingly contributes toward the development of clusters for practical applications. Copyright © 2012 John Wiley & Sons, Ltd.

  5. Fast ion emission from the plasma produced by the PALS laser system

    Czech Academy of Sciences Publication Activity Database

    Wolowski, J.; Badziak, J.; Boody, F. P.; Hora, H.; Hnatowicz, Vladimír; Jungwirth, Karel; Krása, Josef; Láska, Leoš; Parys, P.; Peřina, Vratislav; Pfeifer, Miroslav; Rohlena, Karel; Ryc, L.; Ullschmied, Jiří; Woryna, E.

    2002-01-01

    Roč. 44, - (2002), s. 1277-1283 ISSN 0741-3335 Institutional research plan: CEZ:AV0Z1048901 Keywords : emission * plasma produced * PALS laser system ? Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.121, year: 2002

  6. Ion emission in solids bombarded with Aun+ (n = 1 - 9) clusters accelerated within the 0.15 - 1.25 MeV energy range

    International Nuclear Information System (INIS)

    Wehbe, Nimer

    2006-06-01

    This experimental work is devoted to the study of the ion emission in solids at the impact of gold clusters of energies within 0.15 to 1.25 MeV range. The physics of ion-solid collisions and the theoretical models of sputtering of solids under ion bombardment are presented in the first chapter. The chapter no. 2 deals with the description of the experimental setup. The study of a gold target allowed to evidence the role of the size and energy of the clusters in determining the emission intensity and the mass distribution of the ions. The 4. chapter gives results from the study of cesium iodide in which the intense emission of CsI clusters could be investigated quantitatively due to multiplicity measurements. Finally, the chapter no. 5 was devoted to the study of a biologic molecule, the phenylalanine, and of a pesticide molecule, chlorosulfuron. This work evidenced the importance of clusters for surface analyses by mass spectrometry

  7. Carbon nanotube growth from catalytic nano-clusters formed by hot-ion-implantation into the SiO{sub 2}/Si interface

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Yasushi, E-mail: yhoshino@kanagawa-u.ac.jp [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); Arima, Hiroki; Yokoyama, Ai; Saito, Yasunao; Nakata, Jyoji [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan)

    2012-07-01

    We have studied growth of chirality-controlled carbon nanotubes (CNTs) from hot-implantation-formed catalytic nano-clusters in a thermally grown SiO{sub 2}/Si substrate. This procedure has the advantage of high controllability of the diameter and the number of clusters by optimizing the conditions of the ion implantation. In the present study, Co{sup +} ions with ion dose of 8 Multiplication-Sign 10{sup 16} cm{sup -2} are implanted in the vicinity of the SiO{sub 2}/Si interface at 300 Degree-Sign C temperature. The implanted Co atoms located in the SiO{sub 2} layer has an amorphous-like structure with a cluster diameter of several nm. In contrast, implanted Co atoms in the Si substrate are found to take a cobalt silicide structure, confirmed by the high-resolution image of transmission electron microscope. CNTs are grown by microwave-plasma-enhanced chemical vapor deposition. We have confirmed a large amount of vertically-aligned multi-walled CNTs from the Co nano-clusters formed by the hot-ion-implantation near the SiO{sub 2}/Si interface.

  8. Proceedings of the Cooling, Condensation, and Storage of Hydrogen Cluster Ions Workshop Held in Menlo Park, California on 8-9 January 1987.

    Science.gov (United States)

    1987-12-01

    5. Low susceptibility to accidental annihilation: Because large .4 cluster ions can be dynamically stored and have relatively small physical...1985. 10. Echt 0., Casero R., and Soler J. M., private communication. 7 0 p 0 N’. ’A. "--V ~N A f’~w N’.? .~ N’. ~b0aN N~ Robert L. Forward Prospects

  9. The Effect of Ion Multi-scales on Magnetic Reconnection in Earth's Magnetotail - Cluster Observations"

    Science.gov (United States)

    Shojaei Ardakani, A.; Mouikis, C.; Kistler, L. M.; Torbert, R. B.; Roytershteyn, V.; Omelchenko, Y.

    2017-12-01

    A recent statistical study, using Cluster observations, showed that during substorms, a higher O+ content in the plasma sheet during the substorm growth phase, makes it more difficult to trigger reconnection [Liu et al, 2013]. In addition, they showed that, in contrast to predictions that the reconnection rate during the substorm expansion phase slows down in the presence of O+, the magnetotail unloading rate is actually faster when the O+ content is higher. This could be due to a faster local reconnection rate or due to reconnection occurring over a greater width in the tail when the O+ content of the plasma sheet is high. To address this question, we use reconnection events observed by Cluster that have different densities of O+ and we determine the local reconnection rate. For the calculation of the reconnection rate we use CODIF observations from the boundary layer/lobes around flow reversals where the distribution functions show signatures of the presence of cold plasma convecting towards the current sheet. In addition, we use timing analysis to deduce the movement of the x-line. This methodology will be compared with the estimation of the reconnection rate using results from fully kinetic and hybrid particle-in-cell simulations that model reconnection in the presence of O+ in both local geometry and in a model magnetotail equilibrium. Finally, we use the deduced local reconnection rate together with the total magnetotail pressure rate of change (from Liu et al., [2013]) to estimate the cross-tail extent of the reconnecting plasma sheet.

  10. Optical and electrical properties of disordered layers in GaAs crystals produced by Si+ ion implantation

    International Nuclear Information System (INIS)

    Shigetomi, S.; Matsumori, T.

    1981-01-01

    The ion dose dependence and the annealing behavior of GaAs after implantation with 200 keV 2 x 10 12 -2 x 10 16 Si + ions/cm 2 as studied by using optical absorption, reflection, photoluminescence, sheet-resistivity, Hall effect and field effect methods. The experimental results of the optical absorption and reflection indicate that, when annealed at about 400 0 C, the disordered layers produced by high-dose implantation (2 x 10 15 -2 x 10 16 ions/cm 2 ), reorder epitaxially on the underlying crystal leaving relatively little residual disorder in the near-surface. However, from the experimental results of optical reflection, 800 0 C annealing is required for perfect recrystallization. The temperature dependence of the sheet-resistivity, with annealing temperature as a parameter, indicates that, next to the variable-range hopping and phonon-assisted hopping regions, a new region is observed. Holes, thermally-activated from localized states near the Fermi level Esub(F) to the mobility edge Esub(V) near the valence band, are responsible for electrical conduction in this region. (orig.)

  11. Role of ion magnetization in formation of radial density profile in magnetically expanding plasma produced by helicon antenna

    Science.gov (United States)

    Yadav, Sonu; Ghosh, Soumen; Bose, Sayak; Barada, Kshitish K.; Pal, Rabindranath; Chattopadhyay, Prabal K.

    2018-04-01

    Experimentally, the density profile in the magnetic nozzle of a helicon antenna based plasma device is seen to be modified from being centrally peaked to that of hollow nature as the external magnetic field is increased. It occurs above a characteristic field value when the ions become magnetized in the expansion chamber. The density profile in the source chamber behind the nozzle, however, remains peaked on-axis irrespective of the magnetic field. The electron temperature there is observed to be hollow and this nature is carried to the expansion chamber along the field line. In the electron energy distribution near the off axis peak location, a high energy tail exists. Rotation of these tail electrons in the azimuthal direction due to the gradient-B drift in the expansion chamber leads to an additional off-axis ionization and forms the hollow density profile. It seems that if the ions are not magnetized, then the off-axially produced additional plasma is not confined and the density profile retains the on-axis peak nature. The present experiment successfully demonstrates how the knowledge of the ion magnetization together with tail electrons significantly contributes to the design of an efficient helicon plasma based thruster.

  12. Plasma diagnostics of the SIMPA Ecr ion source by X-ray spectroscopy, Collisions of H-like Neon ions with Argon clusters; Diagnostic du plasma de la source d'ions ECR SIMPA par spectroscopie X, Collision d'ions neon hydrogenoides avec des agregats d'argon

    Energy Technology Data Exchange (ETDEWEB)

    Adrouche, N

    2006-09-15

    The first part of this thesis is devoted to the SIMPA ECR ion source characterization, first, I explored the ion source's capacities on the point of view of extracted currents for three elements, argon, krypton and neon. By analyzing the Bremsstrahlung spectra, I determined the electronic temperature in the plasma and the electronic and ionic densities. In a second time, I recorded high resolution X-spectra of argon and krypton plasma's. By taking into account the principal mechanisms of production of a K hole in the ions inside the plasma, I determined the ionic densities of the high charge states of argon. Lastly, I highlighted a correlation between the ions charge states densities with the intensities of extracted currents. The second part of the thesis is devoted to Ne{sup 9+-} argon clusters collisions. First, I presented simple and effective theoretical models allowing to describe the phenomena occurring during a collision, from the point of view of the projectile. I carried out a simulation for a collision of an ion Ne{sup 9+} with an argon cluster of a given size, which has enabled us to know the energy levels populated during the electronic capture and to follow the number of electrons in each projectile shell. Lastly, I presented the first results of a collision between a Ne{sup 9+} beam and argon clusters. These results, have enabled me by using projectile X-ray spectroscopy during the ions-clusters collision, to evidence a strong clustering of targets atoms and to highlight an electronic multi-capture in the projectile ion excited states. (author)

  13. Ion collisions and deceleration in laser-produced plasma-jet interaction with walls

    Czech Academy of Sciences Publication Activity Database

    Renner, Oldřich; Krouský, Eduard; Liska, R.; Šmíd, M.; Larroche, O.; Dalimier, E.

    2011-01-01

    Roč. 56, - (2011), T165-T174 ISSN 0001-7043 R&D Projects: GA MŠk(CZ) LC528; GA ČR GAP205/10/0814 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser-produced plasma jets * plasma-wall interaction * plasma diagnostics * X-ray spectroscopy * fluid and kinetic plasma simulation Subject RIV: BL - Plasma and Gas Discharge Physics

  14. Increased carrier lifetimes in epitaxial silicon layers on buried silicon nitride produced by ion implantation

    International Nuclear Information System (INIS)

    Skorupa, W.; Kreissig, U.; Hensel, E.; Bartsch, H.

    1984-01-01

    Carrier lifetimes were measured in epitaxial silicon layers deposited on buried silicon nitride produced by high-dose nitrogen implantation at 330 keV. The values were in the range 20-200 μs. The results are remarkable taking into account the high density of crystal defects in the epitaxial layers. Comparing with other SOI technologies the measured lifetimes are higher by 1-2 orders of magnitude. (author)

  15. Radioactive ion beams produced by neutron-induced fission at ISOLDE

    CERN Document Server

    Catherall, R; Gilardoni, S S; Köster, U

    2003-01-01

    The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN, tests have been made on standard ISOLDE actinide targets using fast neutron bunches produced by bombarding thick, high-Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten an...

  16. Changes in cluster magnetism and suppression of local superconductivity in amorphous FeCrB alloy irradiated by Ar{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Okunev, V.D., E-mail: okunev@mail.fti.ac.donetsk.ua [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Samoilenko, Z.A. [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Szymczak, H.; Szewczyk, A.; Szymczak, R.; Lewandowski, S.J.; Aleshkevych, P.; Malinowski, A.; Gierłowski, P.; Więckowski, J. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Wolny-Marszałek, M.; Jeżabek, M. [Institute of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland); Varyukhin, V.N. [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Antoshina, I.A. [Obninsk State Technical University of Atomic Energy, 249020 Obninsk (Russian Federation)

    2016-02-01

    We show that cluster magnetism in ferromagnetic amorphous Fe{sub 67}Cr{sub 18}B{sub 15} alloy is related to the presence of large, D=150–250 Å, α-(Fe Cr) clusters responsible for basic changes in cluster magnetism, small, D=30–100 Å, α-(Fe, Cr) and Fe{sub 3}B clusters and subcluster atomic α-(Fe, Cr, B) groupings, D=10–20 Å, in disordered intercluster medium. For initial sample and irradiated one (Φ=1.5×10{sup 18} ions/cm{sup 2}) superconductivity exists in the cluster shells of metallic α-(Fe, Cr) phase where ferromagnetism of iron is counterbalanced by antiferromagnetism of chromium. At Φ=3×10{sup 18} ions/cm{sup 2}, the internal stresses intensify and the process of iron and chromium phase separation, favorable for mesoscopic superconductivity, changes for inverse one promoting more homogeneous distribution of iron and chromium in the clusters as well as gigantic (twice as much) increase in density of the samples. As a result, in the cluster shells ferromagnetism is restored leading to the increase in magnetization of the sample and suppression of local superconductivity. For initial samples, the temperature dependence of resistivity ρ(T)~T{sup 2} is determined by the electron scattering on quantum defects. In strongly inhomogeneous samples, after irradiation by fluence Φ=1.5×10{sup 18} ions/cm{sup 2}, the transition to a dependence ρ(T)~T{sup 1/2} is caused by the effects of weak localization. In more homogeneous samples, at Φ=3×10{sup 18} ions/cm{sup 2}, a return to the dependence ρ(T)~T{sup 2} is observed. - Highlights: • The samples at high dose of ion irradiation become more homogeneous. • Gigantic increase in density of the samples (twice as much) is observed. • Ferromagnetism in large Fe–Cr clusters is restored. • Ferromagnetism of Fe–Cr clusters suppresses local superconductivity in them. • The participation of quantum defects in scattering of electrons is returned.

  17. New anode material for lithium-ion cells produced by catalytic graphitization of glassy carbon at 1000 degrees C

    Energy Technology Data Exchange (ETDEWEB)

    Skowronski, J.M. [Poznan Univ. of Technology, Poznan (Poland). Inst. of Chemistry and Technical Electrochemistry; Central Lab. of Batteries and Cells, Poznan (Poland); Knofczynski, K. [Central Lab. of Batteries and Cells, Poznan (Poland)

    2006-10-15

    This study investigated the conversion of glassy carbon into graphite at relatively low temperature of 1000 degrees C under ambient pressure using iron powder as the catalyst. The composite product of reaction was a graphite and turbostratic carbon whose use was then examined in terms of application in lithium-ion cells. Glassy, hard carbon spheres of 10 to 15 {iota}m were prepared from phenolic resin in a nitrogen atmosphere and then subjected to heat treatment with an iron powder mixture. After cooling down to ambient temperature, the carbon/iron mixture was treated with diluted HCl solution to remove metallic additives. The modified carbon was then washed with distilled water until chloride ions disappeared in a filtrate. All samples were characterized using XRD analysis. Working electrodes for electrochemical measurements were made by mixing carbons with PVDF. Cyclic voltammograms recorded for unmodified and modified carbons were consistent with XRD measurements. SEM analysis revealed that the process of graphitization begins at the external regions of glassy carbon spheres where erosion occurs when the carbon reacts with iron particles. The surface destruction of carbon spheres progresses into the interior of the spheres, resulting in their collapse followed by the transformation into pallets resembling a stack of graphite sheets. It was noted that not all unorganized carbon was conversed to graphite. Rather, only 50 per cent of turbostratic carbon existed in the product of heat treatment. The product of graphitization appeared to be a promising material for the preparation of anodes for lithium-ion cells. The discharge capacity for carbon produced by catalytic treatment was found to be approximately 5 times higher, while the discharge/charge reversibility was 23 per cent higher than values obtained for untreated carbon. The study showed that the uptake of lithium ions by the original carbon depends on the insertion/deinsertion mechanism of hard carbon as well

  18. Characterization of junctions produced by medium-energy ion implantation in silicon

    International Nuclear Information System (INIS)

    Monfret, A.

    1970-01-01

    Characteristics of diodes made by implanting 20 keV boron and phosphorus ions into silicon are reviewed. Special features of theses diodes are presented, and correlation with technology is studied. This paper includes three parts: - in the first part, the theory of range distribution is considered for both amorphous and single-crystal targets, - In the second part, a brief description of the experimental conditions is given. - In the third part, the experimental results are presented. The results lead to a schematic model of the component. They also show the influence of cleaning and annealing treatments from which optimized process of fabrication can be determined. In this study, the influence of a two stage annealing process is shown. For phosphorus and boron implants, the first stage is performed at 150 deg. C while the second stage is 450 deg. C for phosphorus and 550 deg. C for boron implants. The implanted diodes are found to exhibit good electrical characteristics. Comparisons with standard diffused diodes are quite favourable. (author) [fr

  19. Spectral and ion emission features of laser-produced Sn and SnO2 plasmas

    Science.gov (United States)

    Hui, Lan; Xin-Bing, Wang; Du-Luo, Zuo

    2016-03-01

    We have made a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and SnO2 plasmas under identical experimental conditions. Planar slabs of pure metal Sn and ceramic SnO2 are irradiated with 1.06 μm, 8 ns Nd:YAG laser pulses. Fast photography employing an intensified charge coupled device (ICCD), optical emission spectroscopy (OES), and optical time of flight emission spectroscopy are used as diagnostic tools. Our results show that the Sn plasma provides a higher extreme ultraviolet (EUV) conversion efficiency (CE) than the SnO2 plasma. However, the kinetic energies of Sn ions are relatively low compared with those of SnO2. OES studies show that the Sn plasma parameters (electron temperature and density) are lower compared to those of the SnO2 plasma. Furthermore, we also give the effects of the vacuum degree and the laser pulse energy on the plasma parameters. Project supported by the National Natural Science Foundation of China (Grant No. 11304235) and the Director Fund of WNLO, China.

  20. Photon emission produced by Kr+ ions bombardment of Cr and Cr2O3 targets

    International Nuclear Information System (INIS)

    Boujlaidi, A. El; Hammoum, K.; Jadoual, L.; Jourdani, R.; Ait El Fqih, M.; Aouchiche, H.; Kaddouri, A.

    2015-01-01

    The sputter induced photon spectroscopy technique was used to study the luminescence spectra of the species sputtered from chromium powder and its oxide Cr 2 O 3 , during 5 keV Kr + ions bombardment in vacuum better than 10 −7 torr. The optical spectra recorded between 350 and 470 nm exhibit discrete lines which are attributed to neutral excited atoms of chromium (Cr I lines). The experiments are also performed under 10 −5 torr ultra pure oxygen partial pressure. The results demonstrate that the measured intensities of the emitted photons are always higher in the presence of oxygen and even higher than those obtained for Cr 2 O 3 target. In the presence of oxygen vapor we assume that an oxide film is formed on the chromium surface which is responsible of the increase of photon emission. This variation in the intensities is correctly explained in the model of electron transfer processes between the excited sputtered atom and the bombarded surface. This model suggests that the structure formed on the Cr surface in the case of oxygenated chromium is closer to that of Cr 2 O 3 oxide

  1. Cluster-cluster clustering

    International Nuclear Information System (INIS)

    Barnes, J.; Dekel, A.; Efstathiou, G.; Frenk, C.S.; Yale Univ., New Haven, CT; California Univ., Santa Barbara; Cambridge Univ., England; Sussex Univ., Brighton, England)

    1985-01-01

    The cluster correlation function xi sub c(r) is compared with the particle correlation function, xi(r) in cosmological N-body simulations with a wide range of initial conditions. The experiments include scale-free initial conditions, pancake models with a coherence length in the initial density field, and hybrid models. Three N-body techniques and two cluster-finding algorithms are used. In scale-free models with white noise initial conditions, xi sub c and xi are essentially identical. In scale-free models with more power on large scales, it is found that the amplitude of xi sub c increases with cluster richness; in this case the clusters give a biased estimate of the particle correlations. In the pancake and hybrid models (with n = 0 or 1), xi sub c is steeper than xi, but the cluster correlation length exceeds that of the points by less than a factor of 2, independent of cluster richness. Thus the high amplitude of xi sub c found in studies of rich clusters of galaxies is inconsistent with white noise and pancake models and may indicate a primordial fluctuation spectrum with substantial power on large scales. 30 references

  2. Cathode materials produced by spray flame synthesis for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, NoorAshrina Binti A.

    2013-07-03

    Lithium ion batteries are one of the most enthralling rechargeable energy storage systems for portable application due to their high energy density. Nevertheless, with respect to electromobility innovation towards better electrochemical properties such as higher energy and power density is required. Altering the cathode material used in Li-ion batteries is favorable since the mass- and volume performance is closely related to the cathode electrode mass. Instead of using LiCoO{sub 2} as cathode electrode, LiFePO{sub 4} has gained serious attention as this material owns a high theoretical capacity of 170 mAh g{sup -1}. It is non-toxic, cheap and consists of abundant materials but suffers from low electronic and ionic conductivity. Utilization of nanotechnology methods in combination with composite formation is known to cure this problem effectively. In this work, a new combination of techniques using highly scalable gas-phase synthesis namely spray-flame synthesis and subsequent solid-state reaction has been used to synthesize nanocomposite LiFePO{sub 4}/C. At first this work deals with the formation and characterization of nanosize FePO{sub 4} from a solution of iron(III)acetylacetonate and tributyl phosphate in toluene using spray-flame synthesis. It was shown that a subsequent solid state reaction with Li{sub 2}CO{sub 3} and glucose yielded a LiFePO{sub 4}/C nanocomposite with very promising electrochemical properties. Based on these initial findings the influence of two synthesis parameter - carbon content and annealing temperature - was investigated towards the physicochemical properties of LiFePO{sub 4}/C. It was shown that an annealing temperature of 700 C leads to high purity composite materials consisting of crystalline LiFePO{sub 4} with crystallite sizes well below 100 nm and amorphous carbon consisting of disordered and graphite-like carbon. Variation of glucose amount between 10 and 30 wt% resulted in carbon contents between 2.1 and 7.3 wt%. In parallel

  3. Cathode materials produced by spray flame synthesis for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, NoorAshrina Binti A.

    2013-07-03

    Lithium ion batteries are one of the most enthralling rechargeable energy storage systems for portable application due to their high energy density. Nevertheless, with respect to electromobility innovation towards better electrochemical properties such as higher energy and power density is required. Altering the cathode material used in Li-ion batteries is favorable since the mass- and volume performance is closely related to the cathode electrode mass. Instead of using LiCoO{sub 2} as cathode electrode, LiFePO{sub 4} has gained serious attention as this material owns a high theoretical capacity of 170 mAh g{sup -1}. It is non-toxic, cheap and consists of abundant materials but suffers from low electronic and ionic conductivity. Utilization of nanotechnology methods in combination with composite formation is known to cure this problem effectively. In this work, a new combination of techniques using highly scalable gas-phase synthesis namely spray-flame synthesis and subsequent solid-state reaction has been used to synthesize nanocomposite LiFePO{sub 4}/C. At first this work deals with the formation and characterization of nanosize FePO{sub 4} from a solution of iron(III)acetylacetonate and tributyl phosphate in toluene using spray-flame synthesis. It was shown that a subsequent solid state reaction with Li{sub 2}CO{sub 3} and glucose yielded a LiFePO{sub 4}/C nanocomposite with very promising electrochemical properties. Based on these initial findings the influence of two synthesis parameter - carbon content and annealing temperature - was investigated towards the physicochemical properties of LiFePO{sub 4}/C. It was shown that an annealing temperature of 700 C leads to high purity composite materials consisting of crystalline LiFePO{sub 4} with crystallite sizes well below 100 nm and amorphous carbon consisting of disordered and graphite-like carbon. Variation of glucose amount between 10 and 30 wt% resulted in carbon contents between 2.1 and 7.3 wt%. In parallel

  4. Purification of recombinant aprotinin produced in transgenic corn seed: separation from CTI utilizing ion-exchange chromatography

    Directory of Open Access Journals (Sweden)

    A. R. Azzoni

    2005-09-01

    Full Text Available Protein expression in transgenic plants is considered one of the most promising approaches for producing pharmaceutical proteins. As has happened with other recombinant protein production schemes, the downstream processing (dsp of these proteins produced in plants is key to the technical and economic success of large-scale applications. Since dsp of proteins produced transgenically in plants has not been extensively studied, it is necessary to broaden the investigation in this field in order to more precisely evaluate the commercial feasibility of this route of expression. In this work, we studied the substitution of an IMAC chromatographic step, described in previous work (Azzoni et al., 2002, with ion-exchange chromatography on SP Sepharose Fast Flow resin as the second step in the purification of recombinant aprotinin from transgenic maize seed. The main goal of this second purification step is to separate the recombinant aprotinin from the native corn trypsin inhibitor. Analysis of the adsorption isotherms determined at 25°C under different conditions allowed selection of 0.020 M Tris pH 8.5 as the adsorption buffer. The cation-exchange chromatographic process produced a high-purity aprotinin that was more than ten times more concentrated than that generated using an IMAC step.

  5. ELF waves and ion resonances produced by an electron beam emitting rocket in the ionosphere

    International Nuclear Information System (INIS)

    Winckler, J.R.; Abe, Y.; Erickson, K.N.

    1986-01-01

    Results are reported from the ECHO-6 electron-beam-injection experiment, performed in the auroral-zone ionosphere on March 30, 1983 using a sounding rocket equipped with two electron guns and a free-flying plasma-diagnostics instrument package. The data are presented in extensive graphs and diagrams and characterized in detail. Large ELF wave variations, superposed on the strong beam-sector-directed quasi-dc component, are observed in the 100-eV beam-induced plasma when the beam is injected in a transverse spiral, but not when it is injected upward parallel to the magnetic-field line. ELF activity is found to be suppressed whenever the rocket passed through field lines with auroral activity, suggesting that the waves are produced by the interaction of the beam potentials, plasma currents, and return currents neutralizing the accelerator payload. 12 references

  6. Using MASHA+TIMEPIX Setup for Registration Beta Decay Isotopes Produced in Heavy Ion Induced Reactions

    Science.gov (United States)

    Rodin, A. M.; Belozerov, A. V.; Chernysheva, E. V.; Dmitriev, S. N.; Gulyaev, A. V.; Gulyaeva, A. V.; Itkis, M. G.; Novoselov, A. S.; Oganessian, Yu. Ts.; Salamatin, V. S.; Stepantsov, S. V.; Vedeneev, V. Yu.; Yukhimchuk, S. A.; Krupa, L.; Granja, C.; Pospisil, S.; Kliman, J.; Motycak, S.; Sivacek, I.

    2015-06-01

    Radon and mercury isotopes were produced in multi nucleon transfer (48Ca + 232Th) and complete fusion (48Ca + naturalNd) reactions, respectively. The isotopes with given masses were detected using two detectors: a multi-strip detector of the well-type (made in CANBERRA) and a position-sensitive quantum counting hybrid pixel detector of the TIMEPIX type. The isotopes implanted into the detectors then emit alpha- and betaparticles until reaching the long lived isotopes. The position of the isotopes, the tracks, the time and energy of beta-particles were measured and analyzed. A new software for the particle recognition and data analysis of experimental results was developed and used. It was shown that MASHA+ TIMEPIX setup is a powerful instrument for investigation of neutron-rich isotopes far from stability limits.

  7. Spectral and spatial shaping of a laser-produced ion beam for radiation-biology experiments

    Directory of Open Access Journals (Sweden)

    L. Pommarel

    2017-03-01

    Full Text Available The study of radiation biology on laser-based accelerators is most interesting due to the unique irradiation conditions they can produce, in terms of peak current and duration of the irradiation. In this paper we present the implementation of a beam transport system to transport and shape the proton beam generated by laser-target interaction for in vitro irradiation of biological samples. A set of four permanent magnet quadrupoles is used to transport and focus the beam, efficiently shaping the spectrum and providing a large and relatively uniform irradiation surface. Real time, absolutely calibrated, dosimetry is installed on the beam line, to enable shot-to-shot control of dose deposition in the irradiated volume. Preliminary results of cell sample irradiation are presented to validate the robustness of the full system.

  8. Assessing Many-Body Effects of Water Self-Ions. I: OH-(H2O) n Clusters.

    Science.gov (United States)

    Egan, Colin K; Paesani, Francesco

    2018-04-10

    The importance of many-body effects in the hydration of the hydroxide ion (OH - ) is investigated through a systematic analysis of the many-body expansion of the interaction energy carried out at the CCSD(T) level of theory, extrapolated to the complete basis set limit, for the low-lying isomers of OH - (H 2 O) n clusters, with n = 1-5. This is accomplished by partitioning individual fragments extracted from the whole clusters into "groups" that are classified by both the number of OH - and water molecules and the hydrogen bonding connectivity within each fragment. With the aid of the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method, this structure-based partitioning is found to largely correlate with the character of different many-body interactions, such as cooperative and anticooperative hydrogen bonding, within each fragment. This analysis emphasizes the importance of a many-body representation of inductive electrostatics and charge transfer in modeling OH - hydration. Furthermore, the rapid convergence of the many-body expansion of the interaction energy also suggests a rigorous path for the development of analytical potential energy functions capable of describing individual OH - -water many-body terms, with chemical accuracy. Finally, a comparison between the reference CCSD(T) many-body interaction terms with the corresponding values obtained with various exchange-correlation functionals demonstrates that range-separated, dispersion-corrected, hybrid functionals exhibit the highest accuracy, while GGA functionals, with or without dispersion corrections, are inadequate to describe OH - -water interactions.

  9. Hydration structure and dynamics of a hydroxide ion in water clusters of varying size and temperature: Quantum chemical and ab initio molecular dynamics studies

    International Nuclear Information System (INIS)

    Bankura, Arindam; Chandra, Amalendu

    2012-01-01

    Highlights: ► A theoretical study of hydroxide ion-water clusters is carried for varying cluster size and temperature. ► The structures of OH − (H 2 O) n are found out through quantum chemical calculations for n = 4, 8, 16 and 20. ► The finite temperature behavior of the clusters is studied through ab initio dynamical simulations. ► The spectral features of OH modes (deuterated) and their dependence on hydrogen bonding states of water are discussed. ► The mechanism and kinetics of proton transfer processes in these anionic clusters are also investigated. - Abstract: We have investigated the hydration structure and dynamics of OH − (H 2 O) n clusters (n = 4, 8, 16 and 20) by means of quantum chemical and ab initio molecular dynamics calculations. Quantum chemical calculations reveal that the solvation structure of the hydroxide ion transforms from three and four-coordinated surface states to five-coordinated interior state with increase in cluster size. Several other isomeric structures with energies not very different from the most stable isomer are also found. Ab initio simulations show that the most probable configurations at higher temperatures need not be the lowest energy isomeric structure. The rates of proton transfer in these clusters are found to be slower than that in bulk water. The vibrational spectral calculations reveal distinct features for free OH (deuterated) stretch modes of water in different hydrogen bonding states. Effects of temperature on the structural and dynamical properties are also investigated for the largest cluster considered here.

  10. Failure to produce taste-aversion learning in rats exposed to static electric fields and air ions

    Energy Technology Data Exchange (ETDEWEB)

    Creim, J.A.; Lovely, R.H.; Weigel, R.J.; Forsythe, W.C.; Anderson, L.E. [Pacific Northwest Labs., Richland, WA (United States)

    1995-12-01

    Taste-aversion (TA) learning was measured to determine whether exposure to high-voltage direct current (HVdc) static electric fields can produce TA learning in male Long Evans rats. Fifty-six rats were randomly distributed into four groups of 14 rats each. All rats were placed on a 20 min/day drinking schedule for 12 consecutive days prior to receiving five conditioning trials. During the conditioning trials, access to 0.1% sodium saccharin-flavored water was given for 20 min, followed 30 min later by one of four treatments. Two groups of 14 rats each were individually exposed to static electric fields and air ions, one group to +75 kV/m (+2 {times} 10{sup 5} air ions/cm{sup 3}) and the other group to {minus}75 kV/m ({minus}2 {times} 10{sup 5} air ions/cm{sup 3}). Two other groups of 14 rats each served as sham-exposed controls, with the following variation in one of the sham-exposed groups: this group was subdivided into two subsets of seven rats each, so that a positive control group could be included to validate the experimental design. The positive control group (n = 7) was injected with cyclophosphamide 25 mg/kg, i.p., 30 min after access to saccharin-flavored water on conditioning days, whereas the other subset of seven rats was similarly injected with an equivalent volume of saline. Access to saccharin-flavored water on conditioning days was followed by the treatments described above and was alternated daily with water recovery sessions in which the rats received access to water for 20 min in the home cage without further treatment. Following the last water-recovery session, a 20 min, two-bottle preference test (between water and saccharin-flavored water) was administered to each group. The positive control group did show TA learning, thus validating the experimental protocol.

  11. The adsorption of helium atoms on small cationic gold clusters.

    Science.gov (United States)

    Goulart, Marcelo; Gatchell, Michael; Kranabetter, Lorenz; Kuhn, Martin; Martini, Paul; Gitzl, Norbert; Rainer, Manuel; Postler, Johannes; Scheier, Paul; Ellis, Andrew M

    2018-04-04

    Adducts formed between small gold cluster cations and helium atoms are reported for the first time. These binary ions, Aun+Hem, were produced by electron ionization of helium nanodroplets doped with neutral gold clusters and were detected using mass spectrometry. For a given value of n, the distribution of ions as a function of the number of added helium atoms, m, has been recorded. Peaks with anomalously high intensities, corresponding to so-called magic number ions, are identified and interpreted in terms of the geometric structures of the underlying Aun+ ions. These features can be accounted for by planar structures for Aun+ ions with n ≤ 7, with the addition of helium having no significant effect on the structures of the underlying gold cluster ions. According to ion mobility studies and some theoretical predictions, a 3-D structure is expected for Au8+. However, the findings for Au8+ in this work are more consistent with a planar structure.

  12. Melatonin Protects Human Cells from Clustered DNA Damages, Killing and Acquisition of Soft Agar Growth Induced by X-rays or 970 MeV/n Fe ions

    Energy Technology Data Exchange (ETDEWEB)

    Das, B.; Sutherland, B.; Bennett, P. V.; Cutter, N. C.; Sutherland, J. C.

    2011-06-01

    We tested the ability of melatonin (N-acetyl-5 methoxytryptamine), a highly effective radical scavenger and human hormone, to protect DNA in solution and in human cells against induction of complex DNA clusters and biological damage induced by low or high linear energy transfer radiation (100 kVp X-rays, 970 MeV/nucleon Fe ions). Plasmid DNA in solution was treated with increasing concentrations of melatonin (0.0-3.5 mM) and were irradiated with X-rays. Human cells (28SC monocytes) were also irradiated with X-rays and Fe ions with and without 2 mM melatonin. Agarose plugs containing genomic DNA were subjected to Contour Clamped Homogeneous Electrophoretic Field (CHEF) followed by imaging and clustered DNA damages were measured by using Number Average length analysis. Transformation experiments on human primary fibroblast cells using soft agar colony assay were carried out which were irradiated with Fe ions with or without 2 mM melatonin. In plasmid DNA in solution, melatonin reduced the induction of single- and double-strand breaks. Pretreatment of human 28SC cells for 24 h before irradiation with 2 mM melatonin reduced the level of X-ray induced double-strand breaks by {approx}50%, of abasic clustered damages about 40%, and of Fe ion-induced double-strand breaks (41% reduction) and abasic clusters (34% reduction). It decreased transformation to soft agar growth of human primary cells by a factor of 10, but reduced killing by Fe ions only by 20-40%. Melatonin's effective reduction of radiation-induced critical DNA damages, cell killing, and striking decrease of transformation suggest that it is an excellent candidate as a countermeasure against radiation exposure, including radiation exposure to astronaut crews in space travel.

  13. Study of the defect structures produced by heavy ions in dielectrics by means of small angle scattering

    International Nuclear Information System (INIS)

    Albrecht, D.J.

    1983-11-01

    The aim of the present thesis was to study the defects in dielectrics produced by fast ions. For this the small angle scattering was proved as suitable method. By the production by means of the ion beam of an accelerator the defects possess a pronounced preferential direction. In scattering experiments this system of scattering centers is distinguished by its unusually strong dependence of the sample orientation according to the primary beam. This property was studied, described, and illustrated by examples, and it could by shown that from this additional informations about the scattering defects can be derived. For the first time nuclear tracks were detected by means of small angle neutron scattering. It could be shown that here the same results are obtained as by small angle X-ray scattering. The measured intensity distributions could be assigned to a mathematical model description which gives form, width, and density of the tracks in the position space. On the base of this cylinder model computer codes were established which simulate the scattering experiment regarding the main influences and calculate the expected theoretical intensity distribution. The agreement between calculated and measured scattering distributions proves the validity of the model. The parameters determined by this model, maximal change of density in the track, defect length, radial dilatation, distance of the narrowings and there depth were determined. For the main quantities, radial dilatation and maximal change of densities a simple description of the energy dependence could be given via the energy loss. (orig./HSI) [de

  14. Chemical composition of waterfall-induced air ions: Spectrometry vs. simulations

    Energy Technology Data Exchange (ETDEWEB)

    Parts, T.-E.; Luts, A. [Tartu Univ. (Estonia). Dept. of Environmental Physics; Laakso, L.; Hirsikko, A.; Groenholm, T.; Kulmala, M. [Helsinki Univ. (Finland). Dept. of Physical Sciences

    2007-07-01

    Our measurements of ion size distributions near a waterfall provided new evidence for a waterfall-induced modification of air ion sizes. The ion size spectrum near a waterfall permanently differs from that in ordinary tropospheric air. In this paper we investigated the near-waterfall air ions chemical nature in detail. We carried out a simulation series of air small negative ion evolution, proposing that falling water, as a new environmental component, increases the concentration of OH{sup -} cluster ions. The produced OH{sup -} ions were employed as an extra input for our ion evolution model. The presence of additional OH{sup -} ions resulted in a decrease of typically model-provided NO{sub 3}{sup -} and/or HSO{sub 4}{sup -} cluster ion concentrations and an increase of the abundance of HCO{sub 3}{sup -} cluster ions. Near the waterfall the latter ions became dominant in our simulations. (orig.)

  15. Sifting through genomes with iterative-sequence clustering produces a large, phylogenetically diverse protein-family resource.

    Science.gov (United States)

    Sharpton, Thomas J; Jospin, Guillaume; Wu, Dongying; Langille, Morgan G I; Pollard, Katherine S; Eisen, Jonathan A

    2012-10-13

    New computational resources are needed to manage the increasing volume of biological data from genome sequencing projects. One fundamental challenge is the ability to maintain a complete and current catalog of protein diversity. We developed a new approach for the identification of protein families that focuses on the rapid discovery of homologous protein sequences. We implemented fully automated and high-throughput procedures to de novo cluster proteins into families based upon global alignment similarity. Our approach employs an iterative clustering strategy in which homologs of known families are sifted out of the search for new families. The resulting reduction in computational complexity enables us to rapidly identify novel protein families found in new genomes and to perform efficient, automated updates that keep pace with genome sequencing. We refer to protein families identified through this approach as "Sifting Families," or SFams. Our analysis of ~10.5 million protein sequences from 2,928 genomes identified 436,360 SFams, many of which are not represented in other protein family databases. We validated the quality of SFam clustering through statistical as well as network topology-based analyses. We describe the rapid identification of SFams and demonstrate how they can be used to annotate genomes and metagenomes. The SFam database catalogs protein-family quality metrics, multiple sequence alignments, hidden Markov models, and phylogenetic trees. Our source code and database are publicly available and will be subject to frequent updates (http://edhar.genomecenter.ucdavis.edu/sifting_families/).

  16. The x-ray emission spectra of multicharged xenon ions in a gas puff laser-produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Skobelev, I.Yu.; Dyakin, V.M.; Faenov, A.Ya. [Multicharged Ion Spectra Data Center, VNIIFTRI, Mendeleevo (Russian Federation); Bartnik, A.; Fiedorowicz, H.; Jarocki, R.; Kostecki, J.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Warsaw (Poland); Biemont, E. [Institut de Physique Nucleaire Experimentale, Universite de Liege, Liege (Belgium); Astrophysique et Spectroscopie, Universite de Mons-Hainaut, Mons (Belgium); Quinet, P. [Astrophysique et Spectroscopie, Universite de Mons-Hainaut, Mons (Belgium); Nilsen, J. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Behar, E.; Doron, R.; Mandelbaum, P.; Schwob, J.L. [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem (Israel)

    1999-01-14

    Emission spectra of multicharged xenon ions produced by a laser gas puff are observed with high spectral resolution in the 8.5-9.5 and 17-19 A wavelength ranges. Three different theoretical methods are employed to obtain 3l-n'l'(n' = 4 to 10) wavelengths and Einstein coefficients for Ni-like Xe{sup 26+}. For the 3d-4p transitions, very good agreement is found between the experimental wavelengths and the various theoretical wavelengths. These accurate energy level measurements can be useful for studying the Ni-like xenon x-ray laser scheme. On the other hand, several intense spectral lines could not be identified as 3l-n'l' lines of Ni-like xenon, despite the very good agreement between the wavelengths and Einstein coefficients calculated for these transitions using the three different methods. (author)

  17. Cluster observations of band-limited Pc 1 waves associated with streaming H+ and O+ ions in the high-altitude plasma mantle

    Science.gov (United States)

    Engebretson, M. J.; Kahlstorf, C. R. G.; Murr, D. L.; Posch, J. L.; Keiling, A.; Lavraud, B.; Rème, H.; Lessard, M. R.; Kim, E.-H.; Johnson, J. R.; Dombeck, J.; Grison, B.; Robert, P.; Glassmeier, K.-H.; Décréau, P. M. E.

    2012-10-01

    Bursts of band-limited Pc 1 waves (0.2 to ˜1.0 Hz) with normalized frequency f/fH+ ˜ 0.5 have been observed by the Cluster spacecraft during many passes through the high-latitude plasma mantle. These transverse, left-hand polarized waves are associated with regions of H+ and O+ ions streaming away from Earth along magnetic field lines at the same velocity (˜140 km/s). Waves were observed only when H+ fluxes increased by factors of 10-1000 and energies of both ion species increased by factors of up to 10. We present two satellite-ground conjunctions to demonstrate the high latitude localization of these waves and their ability to reach the polar ionosphere and two extended examples of waves and associated ion distribution functions near the southern dusk flank magnetopause. We also present the results of a search for all such events during Cluster's 2002 and 2003 passages through the magnetotail, with orbital precession covering dawn to dusk on Earth's night side (June through December). A total of 46 events (band-limited Pc 1-2 waves accompanied by a sustained population of streaming H+ and O+ ions, separated by at least 12 min) were observed on 29 days. The waves were generally associated with intervals of southward IMF Bz and/or large IMF By (times of active cusp reconnection), and often but not always occurred during the main phase or early recovery phase of magnetic storms. Analysis of selected events shows that the waves are associated with large H+ temperature anisotropy, and that the waves propagate opposite to the direction of the streaming ions. A wave instability analysis using the WHAMP code confirms that the generation of these waves, via the ion cyclotron instability, is basically consistent with known physics. Their extended region of wave growth is likely, however, to reach tailward significantly beyond the Cluster orbit.

  18. Sifting through genomes with iterative-sequence clustering produces a large, phylogenetically diverse protein-family resource

    Directory of Open Access Journals (Sweden)

    Sharpton Thomas J

    2012-10-01

    Full Text Available Abstract Background New computational resources are needed to manage the increasing volume of biological data from genome sequencing projects. One fundamental challenge is the ability to maintain a complete and current catalog of protein diversity. We developed a new approach for the identification of protein families that focuses on the rapid discovery of homologous protein sequences. Results We implemented fully automated and high-throughput procedures to de novo cluster proteins into families based upon global alignment similarity. Our approach employs an iterative clustering strategy in which homologs of known families are sifted out of the search for new families. The resulting reduction in computational complexity enables us to rapidly identify novel protein families found in new genomes and to perform efficient, automated updates that keep pace with genome sequencing. We refer to protein families identified through this approach as “Sifting Families,” or SFams. Our analysis of ~10.5 million protein sequences from 2,928 genomes identified 436,360 SFams, many of which are not represented in other protein family databases. We validated the quality of SFam clustering through statistical as well as network topology–based analyses. Conclusions We describe the rapid identification of SFams and demonstrate how they can be used to annotate genomes and metagenomes. The SFam database catalogs protein-family quality metrics, multiple sequence alignments, hidden Markov models, and phylogenetic trees. Our source code and database are publicly available and will be subject to frequent updates (http://edhar.genomecenter.ucdavis.edu/sifting_families/.

  19. Cluster induced ignition - A new approach to inertial fusion energy

    International Nuclear Information System (INIS)

    Desai, T.; Mendonca, J.T.; Batani, D.; Bernardinello, A.

    2001-01-01

    An ultra intense laser interaction with clusters produce energetic ions and electrons in MeV range due to cluster explosion. Here we discuss the possibility of harnessing these particle energies to heat a part of the pre compressed DT fuel to ignition condition. In this article we are striving to present the principle concept and the preliminary results are discussed. (author)

  20. Switch-on of the ion emitters on experiment ASPOC/CLUSTER, recovered from the debris of the ARIANE-V maiden flight disaster

    International Nuclear Information System (INIS)

    Fehringer, M.; Ruedenauer, F.; Arends, H.

    1996-11-01

    Within the project ASPOC, Seibersdorf has developed the ion emitter modules for potential control of the four CLUSTER - satellites. During start of the CLUSTER - mission, the ARIANE - V carrier had to be destroyed at an altitude of 3.8 km, due to a misprogramming of the inertial platform. From the debris of the disaster, three of the four ASPOC - experiments were recovered. Approximately 2 months after the disaster, the ion emitter modules were shipped to Seibersdorf for an investigation of the influence of the extreme stresses on the emitter structures. In spite of the mechanical stresses due to the explosion and the 4 km drop, and in spite of the fact that the emitters were exposed to the damp subtropical environment for about 2 months, all recovered emitters refired in the laboratory at the first attempt. Operating conditions after refiring corresponded closely to the parameters obtained during preflight - testing. (author)

  1. Clustering of color sources and the shear viscosity of the QGP in heavy ion collisions at RHIC and LHC energies

    Energy Technology Data Exchange (ETDEWEB)

    Dias de Deus, J. [Instituto Superior Tecnico, CENTRA, Lisbon (Portugal); Hirsch, A.S.; Scharenberg, R.P.; Srivastava, B.K. [Purdue University, Department of Physics, West Lafayette, IN (United States); Pajares, C. [Universidale de Santiago de Compostela and Instituto Galego de Fisica de Atlas Enerxias (IGFAE), Departamento de Fisica de Particulas, Santiago, de Compostela (Spain)

    2012-08-15

    We present our results on the shear viscosity to entropy ratio ({eta}/s) in the framework of the clustering of the color sources of the matter produced at RHIC and LHC energies. The onset of de-confinement transition is identified by the spanning percolating cluster in 2D percolation. The relativistic kinetic theory relation for {eta}/s is evaluated using the initial temperature (T) and the mean free path ({lambda}{sub mfp}). The analytic expression for {eta}/s covers a wide temperature range. At T{proportional_to}150 MeV below the hadron to QGP transition temperature of {proportional_to}168 MeV, with increasing temperatures the {eta}/s value drop sharply and reaches a broad minimum {eta}/s{proportional_to}0.20 at T{proportional_to}175-185 MeV. Above this temperature {eta}/s grows slowly. The measured values of {eta}/s are 0.204{+-}0.020 and 0.262{+-}0.026 at the initial temperature of 193.6{+-}3 MeV from central Au+Au collisions at {radical}(s{sub NN})=200{proportional_to}GeV (RHIC) and 262.2{+-}13 MeV in central Pb+Pb collisions at {radical}(s{sub NN})= 2.76{proportional_to}TeV (LHC). These {eta}/s values are 2.5 and 3.3 times the AdS/CFT conjectured lower bound 1/4{pi} but are consistent with theoretical {eta}/s estimates for a strongly coupled QGP. (orig.)

  2. Formation of large clusters during sputtering of silver

    International Nuclear Information System (INIS)

    Staudt, C.; Heinrich, R.; Wucher, A.

    2000-01-01

    We have studied the formation of polyatomic clusters during sputtering of metal surfaces by keV ion bombardment. Both positively charged (secondary cluster ions) and neutral clusters have been detected in a time-of-flight mass spectrometer under otherwise identical experimental conditions, the sputtered neutrals being post-ionized by single photon absorption using a pulsed 157 nm VUV laser beam. Due to the high achievable laser intensity, the photoionization of all clusters could be saturated, thus enabling a quantitative determination of the respective partial sputtering yields. We find that the relative yield distributions of sputtered clusters are strongly correlated with the total sputtering yield in a way that higher yields lead to higher abundances of large clusters. By using heavy projectile ions (Xe + ) in connection with bombarding energies up to 15 keV, we have been able to detect sputtered neutral silver clusters containing up to about 60 atoms. For cluster sizes above 40 atoms, doubly charged species are shown to be produced in the photoionization process with non-negligible efficiency. From a direct comparison of secondary neutral and ion yields, the ionization probability of sputtered clusters is determined as a function of the cluster size. It is demonstrated that even the largest silver clusters are still predominantly sputtered as neutrals

  3. Studies of radiation-produced radicals and radical ions. Progress report, June 1, 1981-August 31, 1982

    International Nuclear Information System (INIS)

    Williams, T.F.

    1982-01-01

    The discovery and characterization of novel radical ions produced by the γ irradiation of solids continues to be a fertile field for investigation. This Progress Report describes the generation and ESR identification of several new paramagnetic species, some of which have long been sought as important intermediates in radiation chemistry. We have also contributed to a general theoretical problem in ESR spectroscopy. Solid-state studies of electron attachment reactions, both non-dissociative and dissociative, reveal interesting structural and chemical information about the molecular nature of these processes for simple compounds. In particular, ESR measurements of the spin distribution in the products allow a fairly sharp distinction to be drawn between radical anions and radical-anion pairs or adducts. Dimer radical anion formation can also take place but the crystal structure plays a role in this process, as expected. Some radical anions undergo photolysis to give radical-anion pairs which may then revert back to the original radical anion by a thermal reaction. The chemistry of these reversible processes is made more intricate by a competing reaction in which the radical abstracts a hydrogen atom from a neighboring molecule. However, the unraveling of this complication has also served to extend our knowledge of the role of quantum tunneling in chemical reactions. The results of this investigation testify to the potential of solid-state techniques for the study of novel and frangible radical ions. Progress in this field shows no sign of abating, as witness the recent discovery of perfluorocycloalkane radical anions and alkane radical cations

  4. Observations of different core water cluster ions Y-(H2O)n (Y = O2, HOx, NOx, COx) and magic number in atmospheric pressure negative corona discharge mass spectrometry.

    Science.gov (United States)

    Sekimoto, Kanako; Takayama, Mitsuo

    2011-01-01

    Reliable mass spectrometry data from large water clusters Y(-)(H(2)O)(n) with various negative core ions Y(-) such as O(2)(-), HO(-), HO(2)(-), NO(2)(-), NO(3)(-), NO(3)(-)(HNO(3))(2), CO(3)(-) and HCO(4)(-) have been obtained using atmospheric pressure negative corona discharge mass spectrometry. All the core Y(-) ions observed were ionic species that play a central role in tropospheric ion chemistry. These mass spectra exhibited discontinuities in ion peak intensity at certain size clusters Y(-)(H(2)O)(m) indicating specific thermochemical stability. Thus, Y(-)(H(2)O)(m) may correspond to the magic number or first hydrated shell in the cluster series Y(-)(H(2)O)(n). The high intensity discontinuity at HO(-)(H(2)O)(3) observed was the first mass spectrometric evidence for the specific stability of HO(-)(H(2)O)(3) as the first hydrated shell which Eigen postulated in 1964. The negative ion water clusters Y(-)(H(2)O)(n) observed in the mass spectra are most likely to be formed via core ion formation in the ambient discharge area (760 torr) and the growth of water clusters by adiabatic expansion in the vacuum region of the mass spectrometers (≈1 torr). The detailed mechanism of the formation of the different core water cluster ions Y(-)(H(2)O)(n) is described. Copyright © 2010 John Wiley & Sons, Ltd.

  5. The observation of the Ne-like ion resonance line satellites for CrXV ... Ni XIX CO2-laser produced plasma

    International Nuclear Information System (INIS)

    Khakhalin, S.Ya.; Faenov, A.Ya.; Skobelev, I.Yu.; Pikuz, S.A.; Nilsen, J.; Osterheld, A.

    1994-01-01

    We present an analysis of dielectronic satellite spectra of Ne-like ion resonance lines for elements from Cr to Ni. For these low-Z elements, we use spectra from strongly underionized CO 2 -laser produced plasma to minimize the emission from open L-shell ions. This simplifies the spectra and allows the identification of satellite lines caused by radiative transitions from autoionizing states of sodium like ions. Good agreement between the satellite structure calculations and the experimental emission spectra is obtained. (orig.)

  6. The observation of the Ne-like ion resonance line satellites for CrXV. Ni XIX CO[sub 2]-laser produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Khakhalin, S.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Faenov, A.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Skobelev, I.Yu. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Pikuz, S.A. (P. N. Lebedev Physical Inst., Russian Academy of Science, Moscow (Russian Federation)); Nilsen, J. (Lawrence Livermore National Lab., Livermore, CA (United States)); Osterheld, A. (Lawrence Livermore National Lab., Livermore, CA (United States))

    1994-08-01

    We present an analysis of dielectronic satellite spectra of Ne-like ion resonance lines for elements from Cr to Ni. For these low-Z elements, we use spectra from strongly underionized CO[sub 2]-laser produced plasma to minimize the emission from open L-shell ions. This simplifies the spectra and allows the identification of satellite lines caused by radiative transitions from autoionizing states of sodium like ions. Good agreement between the satellite structure calculations and the experimental emission spectra is obtained. (orig.).

  7. Identification and activation of novel biosynthetic gene clusters by genome mining in the kirromycin producer Streptomyces collinus Tü 365

    DEFF Research Database (Denmark)

    Iftime, Dumitrita; Kulik, Andreas; Härtner, Thomas

    2016-01-01

    Streptomycetes are prolific sources of novel biologically active secondary metabolites with pharmaceutical potential. S. collinus Tü 365 is a Streptomyces strain, isolated 1972 from Kouroussa (Guinea). It is best known as producer of the antibiotic kirromycin, an inhibitor of the protein biosynth......Streptomycetes are prolific sources of novel biologically active secondary metabolites with pharmaceutical potential. S. collinus Tü 365 is a Streptomyces strain, isolated 1972 from Kouroussa (Guinea). It is best known as producer of the antibiotic kirromycin, an inhibitor of the protein...

  8. Accurate argon cluster-ion sputter yields: Measured yields and effect of the sputter threshold in practical depth-profiling by x-ray photoelectron spectroscopy and secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Cumpson, Peter J.; Portoles, Jose F.; Barlow, Anders J.; Sano, Naoko [National EPSRC XPS User' s Service (NEXUS), School of Mechanical and Systems Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU (United Kingdom)

    2013-09-28

    Argon Gas Cluster-Ion Beam sources are likely to become widely used on x-ray photoelectron spectroscopy and secondary ion mass spectrometry instruments in the next few years. At typical energies used for sputter depth profiling the average argon atom in the cluster has a kinetic energy comparable with the sputter threshold, meaning that for the first time in practical surface analysis a quantitative model of sputter yields near threshold is needed. We develop a simple equation based on a very simple model. Though greatly simplified it is likely to have realistic limiting behaviour and can be made useful for estimating sputter yields by fitting its three parameters to experimental data. We measure argon cluster-ion sputter yield using a quartz crystal microbalance close to the sputter threshold, for silicon dioxide, poly(methyl methacrylate), and polystyrene and (along with data for gold from the existing literature) perform least-squares fits of our new sputter yield equation to this data. The equation performs well, with smaller residuals than for earlier empirical models, but more importantly it is very easy to use in the design and quantification of sputter depth-profiling experiments.

  9. Inulin-type fructan degradation capacity of Clostridium cluster IV and XIVa butyrate-producing colon bacteria and their associated metabolic outcomes.

    Science.gov (United States)

    Moens, F; De Vuyst, L

    2017-05-30

    Four selected butyrate-producing colon bacterial strains belonging to Clostridium cluster IV (Butyricicoccus pullicaecorum DSM 23266 T and Faecalibacterium prausnitzii DSM 17677 T ) and XIVa (Eubacterium hallii DSM 17630 and Eubacterium rectale CIP 105953 T ) were studied as to their capacity to degrade inulin-type fructans and concomitant metabolite production. Cultivation of these strains was performed in bottles and fermentors containing a modified medium for colon bacteria, including acetate, supplemented with either fructose, oligofructose, or inulin as the sole energy source. Inulin-type fructan degradation was not a general characteristic among these strains. B. pullicaecorum DSM 23266 T and E. hallii DSM 17630 could only ferment fructose and did not degrade oligofructose or inulin. E. rectale CIP 105953 T and F. prausnitzii DSM 17677 T fermented fructose and could degrade both oligofructose and inulin. All chain length fractions of oligofructose were degraded simultaneously (both strains) and both long and short chain length fractions of inulin were degraded either simultaneously (E. rectale CIP 105953 T ) or consecutively (F. prausnitzii DSM 17677 T ), indicating an extracellular polymer degradation mechanism. B. pullicaecorum DSM 23266 T and E. hallii DSM 17630 produced high concentrations of butyrate, CO 2 , and H 2 from fructose. E. rectale CIP 105953 T produced lactate, butyrate, CO 2 , and H 2 , from fructose, oligofructose, and inulin, whereas F. prausnitzii DSM 17677 T produced butyrate, formate, CO 2 , and traces of lactate from fructose, oligofructose, and inulin. Based on carbon recovery and theoretical metabolite production calculations, an adapted stoichiometrically balanced metabolic pathway for butyrate, formate, lactate, CO 2 , and H 2 production by members of both Clostridium cluster IV and XIVa butyrate-producing bacteria was constructed.

  10. Carbon-cluster mass calibration at SHIPTRAP

    International Nuclear Information System (INIS)

    Chaudhuri, Ankur

    2007-01-01

    A carbon-cluster ion source has been installed and tested at SHIPTRAP, the Penning-trap mass spectrometer for mass measurements of heavy elements at GSI/Darmstadt, Germany. A precision mass determination is carried out by measuring the ion cyclotron frequency ω c =qB=m, where q/m is the charge-to-mass ratio of the ion and B is the magnetic field. The mass of the ion of interest is obtained from the comparison of its cyclotron frequency ω c with that of a well-known reference ion. Carbon clusters are the mass reference of choice since the unified atomic mass unit is defined as 1/12 of the mass of the 12 C atom. Thus the masses of carbon clusters 12 C n , n=1,2,3,.. are multiples of the unified atomic mass unit. Carbon-cluster ions 12 C n + , 5≤n≤23, were produced by laser-induced desorption and ionization from a carbon sample. Carbon clusters of various sizes ( 12 C 7 + , 12 C 9 + , 12 C 10 + , 12 C 11 + , 12 C 12 + , 12 C 15 + , 12 C 18 + , 12 C 19 + , 12 C 20 + ) were used for an investigation of the accuracy of SHIPTRAP covering a mass range from 84 u to 240 u. To this end the clusters were used both as ions of interest and reference ions. Hence the true values of the frequency ratios are exactly known. The mass-dependent uncertainty was found to be negligible for the case of (m-m ref ) -8 was revealed. In addition, carbon clusters were employed for the first time as reference ions in an on-line studies of short-lived nuclei. Absolute mass measurements of the radionuclides 144 Dy, 146 Dy and 147 Ho were performed using 12 C 11 + as reference ion. The results agree with measurements during the same run using 85 Rb + as reference ion. The investigated radionuclides were produced in the fusion-evaporation reaction 92 Mo( 58 Ni,xpyn) at SHIP (Separator for Heavy Ion reaction Products) at GSI. Among the measured nuclei 147 Ho has the lowest half life (5.8 s). A relative mass uncertainty of 5 x 10 -8 was obtained from the mass measurements using carbon clusters

  11. Quantification of trace level of fluoride content in uranium oxide produced by deconversion of HEX gas by ion chromatography

    International Nuclear Information System (INIS)

    Unnikrishnan, E.K.; Padmakumar, P.R.; Shanmugavelu, P.; Sudhakar, T.M.; Bhowmik, A.

    2015-01-01

    Fluoride content in nuclear fuel is detrimental due to its corrosion behavior with cladding material. It is essential to monitor and control the fluoride concentration in nuclear material at various processing stages. Deconversion of upgraded HEX gas is carried out to produce uranium oxide. The performance of the deconversion process of HEX gas is evaluated for which trace level of fluoride concentration accompanying uranium oxide is considered as a marker. An analytical method has been developed for testing the uranium oxide produced from deconversion process of HEX gas. The method involves sample pretreatment followed by analysis using ion chromatography. The test method was validated for its performance using in house synthetic uranyl fluoride (UO 2 F 2 ) standard solutions prepared with different level of fluoride content. The results are in agreement with the expected values with the recovery in the range of 80-95%. This method has been successfully implemented for routine analysis of samples at our lab. Since UO 2 F 2 reference material is not available to validate this method, in house UO 2 F 2 standards were prepared from U 3 O 8 prepared from nuclear grade uranyl nitrate solution. UO 2 F 2 standards were prepared by converting U 3 O 8 to UO 2 F 2 by the addition of HF followed by H 2 O 2 at 200°C on a hot plate. The entire yellow colored UO 2 F 2 was dissolved in nano pure water and recrystallised several times to ensure that all free HF is removed. The crystals dried in air oven at 120° for three hours. Samples containing 1000 mg kg -1 fluoride prepared from this UO 2 F 2 , and subsequently from this sample containing 5 mg kg -1 to 35 mg kg -1 fluoride samples were prepared and analysed against fluoride CRM and the fluoride concentration obtained was analysed

  12. Beams of mass-selected clusters: realization and first experiments

    International Nuclear Information System (INIS)

    Kamalou, O.

    2007-04-01

    The main objective of this work concerns the production of beams of mass-selected clusters of metallic and semiconductor materials. Clusters are produced in magnetron sputtering source combined with a gas aggregation chamber, cooled by liquid nitrogen circulation. Downstream of the cluster source, a Wiley-McLaren time-of-flight setup allows to select a given cluster size or a narrow size range. The pulsed mass-selected cluster ion beam is separated from the continuous neutral one by an electrostatic 90-quadrupole deflector. After the deflector, the density of the pulsed beam amounts to about 10 3 particles/cm 3 . Preliminary deposition experiments of mass-selected copper clusters with a deposition energy of about 0.5 eV/atom have ben performed on highly oriented pyrolytic graphite (HOPG) substrates, indicating that copper clusters are evidently mobile on the HOPG-surface until they reach cleavage steps, dislocation lines or other surface defects. In order to lower the cluster mobility on the HOPG-surface, we have first irradiated HOPG samples with slow highly charged ions (high dose) in order to create superficial defects. In a second step we have deposited mass-selected copper clusters on these pre-irradiated samples. The first analysis by AFM (Atomic Force Microscopy) techniques showed that the copper clusters are trapped on the defects produced by the highly charged ions. (author)

  13. Measurement of the ratio of C3+ and O4+ ions produced by ECRIS to prepare a laser cooling experiment at storage rings

    International Nuclear Information System (INIS)

    Zhu, X.L.; Wen, W.Q.; Ma, X.; Li, J.Y.; Feng, W.T.; Zhang, R.T.; Wang, Enliang; Yan, S.; Guo, D.L.; Hai, B.; Qian, D.B.; Zhang, P.; Xu, S.; Zhao, D.M.; Yang, J.; Zhang, D.C.; Li, B.; Gao, Y.; Huang, Z.K.; Wang, H.B.

    2014-01-01

    To prepare the upcoming laser cooling of relativistic C 3+ ion beams at the experimental Cooler Storage Ring (CSRe), a novel experiment was performed using a reaction microscope to determine the ratio of C 3+ ions in mixed ion beams of C 3+ and O 4+ that are produced by an Electron Cyclotron Resonance Ion Source (ECRIS). The mixed ion beams at an energy of 4 keV/u were directed to collide on a supersonic helium gas target. Using the single-electron capture channel and the coincidence technique, the fractions of C 3+ and O 4+ ions in the primary beam were obtained. Using different injection gases for ECRIS, including O 2 , CO, CO 2 , and CH 4 , at a fixed radio-frequency power of 300 W, the measured results showed that the fraction of C 3+ ions was greater than 70% for the injection gases of CO and CO 2 . These measured results are very important and helpful for the upcoming laser cooling experiments

  14. Revealing dynamically-organized receptor ion channel clusters in live cells by a correlated electric recording and super-resolution single-molecule imaging approach.

    Science.gov (United States)

    Yadav, Rajeev; Lu, H Peter

    2018-03-28

    The N-methyl-d-aspartate (NMDA) receptor ion-channel is activated by the binding of ligands, along with the application of action potential, important for synaptic transmission and memory functions. Despite substantial knowledge of the structure and function, the gating mechanism of the NMDA receptor ion channel for electric on-off signals is still a topic of debate. We investigate the NMDA receptor partition distribution and the associated channel's open-close electric signal trajectories using a combined approach of correlating single-molecule fluorescence photo-bleaching, single-molecule super-resolution imaging, and single-channel electric patch-clamp recording. Identifying the compositions of NMDA receptors, their spatial organization and distributions over live cell membranes, we observe that NMDA receptors are organized inhomogeneously: nearly half of the receptor proteins are individually dispersed; whereas others exist in heterogeneous clusters of around 50 nm in size as well as co-localized within the diffraction limited imaging area. We demonstrate that inhomogeneous interactions and partitions of the NMDA receptors can be a cause of the heterogeneous gating mechanism of NMDA receptors in living cells. Furthermore, comparing the imaging results with the ion-channel electric current recording, we propose that the clustered NMDA receptors may be responsible for the variation in the current amplitude observed in the on-off two-state ion-channel electric signal trajectories. Our findings shed new light on the fundamental structure-function mechanism of NMDA receptors and present a conceptual advancement of the ion-channel mechanism in living cells.

  15. Novel uses of a wide beam saddle field ion source for producing targets used in nuclear physics experiments at the Argonne National Laboratory ATLAS facility

    International Nuclear Information System (INIS)

    Greene, J.P.; Thomas, G.E.

    1996-01-01

    The wide beam ion sputter source has several unique characteristics which make it very useful for producing, reducing the thickness or cleaning the surface of targets needed for nuclear physics experiments. A discussion of these techniques as well as the sputter source characteristics will be given. Sputter yields obtained utilizing the source are presented for a variety of materials common to nuclear target production

  16. Imaging with Mass Spectrometry: A SIMS and VUV-Photoionization Study of Ion-Sputtered Atoms and Clusters from GaAs and Au

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Lynelle; Zhou, Jia; Wilson, Kevin R.; Leone, Stephen R.; Ahmed, Musahid

    2008-12-05

    A new mass spectrometry surface imaging method is presented in which ion-sputtered neutrals are postionized by wavelength-tunable vacuum ultraviolet (VUV) light from a synchrotron source. Mass spectra and signal counts of the photoionized neutrals from GaAs (100) and Au are compared to those of the secondary ions. While clusters larger than dimers are more efficiently detected as secondary ions, certain species, such as As2, Au and Au2, are more efficiently detected through the neutral channel. Continuously tuning the photon wavelength allows photoionization efficiency (PIE) curves to be obtained for sputtered Asm (m=1,2) and Aun (n=1-4). From the observed ionization thresholds, sputtered neutral As and Au show no clear evidence of electronic excitation, while neutral clusters have photoionization onsets shifted to lower energies by ~;;0.3 eV. These shifts are attributed to unresolved vibrational and rotational excitations. High-spatial resolution chemical imaging with synchrotron VUV postionization is demonstrated at two different photon energies using a copper TEM grid embedded in indium. The resulting images are used to illustrate the use of tunable VUV light for verifying mass peak assignments by exploiting the unique wavelength-dependent PIE of each sputtered neutral species. This capability is valuable for identifying compounds when imaging chemically complex systems with mass spectrometry-based techniques.

  17. Relationship between Statistical and Dynamical properties of fragments produced at Fermi Energy in Heavy ion collisions: ng

    International Nuclear Information System (INIS)

    Lehaut, G.

    2009-10-01

    The properties of the fragments produced in heavy-ion collisions around the Fermi energy have been studie