Towards 20 A negative hydrogen ion beams for up to 1 h: Achievements of the ELISE test facility (invited)

International Nuclear Information System (INIS)

Fantz, U.; Heinemann, B.; Wünderlich, D.; Riedl, R.; Kraus, W.; Nocentini, R.; Bonomo, F.

2016-01-01

The large-scale RF-driven ion source of the test facility extraction from a large ion source experiment is aimed to deliver an accelerated ion current of 20 A D − (23 A H − ) with an extracted electron-to-ion ratio below one for up to 1 h. Since the first plasma pulses for 20 s in volume operation in early 2013, followed by caesiation of the ion source, substantial progress has been achieved in extending the pulse length and the RF power. The record pulses in hydrogen are stable 400 s pulses with an extracted ion current of 18.3 A at 180 kW total RF power and 9.3 A at 80 kW stable for 1 h. For deuterium pulse, length and RF power are limited by the amount of co-extracted electrons

H- ion production from different converter materials

International Nuclear Information System (INIS)

Leung, K.N.; Ehlers, K.W.

1984-10-01

For heating plasmas and for current drive in some fusion reactors, high energy neutral beams may be required. The high neutralization efficiency of H - or D - ions makes them favorable to form neutral atoms with energies in excess of 160 keV. It has been shown that a steady-state H - ion beam with current greater than 1 A can be generated by a surface conversion type source with Mo being used as the converter material. In order to achieve the proper cesium coverage and thereby increasing the H - ion yield, the application of porous cesium-dispensing converters is being investigated. It is also possible to optimize the H - production by choosing the proper converter material. In this paper, we compare the negative ion yield generated by different materials (such as Mo, Ti, V, Nb, Pt, Pd, Rh, Cu, Ta, Al, Au, LaB 6 and stainless-steel) in the pure hydrogen and cesium-hydrogen modes of operation

Correlation of H- production and the work function of a surface in a hydrogen plasma

International Nuclear Information System (INIS)

Wada, M.

1983-03-01

Surface-plasma negative hydrogen ion sources are being developed as possible parts for future neutral beam systems. In these ion sources, negative hydrogen ions (H - ) are produced at low work function metal surfaces immersed in hydrogen plasmas. To investigate the correlation between the work function and the H - production at the surface with a condition similar to the one in the actual plasma ion source, these two parameters were simultaneously measured in the hydrogen plasma environment

Sputtering of solid nitrogen and oxygen by keV hydrogen ions

DEFF Research Database (Denmark)

Ellegaard, O.; Schou, Jørgen; Stenum, B.

1994-01-01

Electronic sputtering of solid nitrogen and oxygen by keV hydrogen ions has been studied at two low-temperature setups. The yield of the sputtered particles has been determined in the energy regime 4-10 keV for H+, H-2+ and H-3+ ions. The yield for oxygen is more than a factor of two larger than...... that for nitrogen. The energy distributions of the sputtered N2 and O2 molecules were measured for hydrogen ions in this energy regime as well. The yields from both solids turn out to depend on the sum of the stopping power of all atoms in the ion. The yield increases as a quadratic function of the stopping power...

H- formation process in a multicusp ion source

International Nuclear Information System (INIS)

Leung, K.N.; Kunkel, W.B.

1987-07-01

In recent years, H - ions have been found important applications in high energy accelerators and in neutral beam heating of fusion plasmas. There are different techniques for producing the H - or D - ions. The most attractive scheme is the direct extraction of H - ions from a hydrogen discharge. This technique requires no cesium and it utilizes the existing large area positive ion source technology. This paper investigates this techniques. 14 refs

Extraction of negative lithium ions from a lithium-containing hydrogen plasma

International Nuclear Information System (INIS)

Wada, M.; Sasao, M.

1996-01-01

Negative lithium ions (Li - ) were extracted from a 6-cm-diam 7-cm-long negative hydrogen ion (H - ) source to simulate the condition of Li - extraction from a Li vapor introduced ion source for the neutral beam heating. The amount of the Li - current extracted from a hydrogen plasma with Li vapor was comparable to that extracted from a pure Li plasma. However, the amount of the H - current decreased as the H 2 gas pressure in the source decreased due to a getter-pump effect of Li during the introduction of Li vapor. A heat shield installed to keep a high wall temperature was effective in mitigating the pressure decrease. However, the H - current extracted from the ion source equipped with the heat shield became 20% of the original value, as Li vapor was injected into the ion source. copyright 1996 American Institute of Physics

Trapping of hydrogen isotopes in molybdenum and niobium predamaged by ion implantation

International Nuclear Information System (INIS)

Bottiger, J.; Picraux, S.T.; Rud, N.; Laursen, T.

1977-01-01

The trapping of hydrogen isotopes at defects in Mo and Nb have been studied. Ion beams of 11- and 18-keV He + , 55-keV O + and Ne + , and 500-keV Bi + were used to create defects. Subsequently H or D was injected at room temperature by use of molecular beams of 16-keV H + 2 and D + 2 . Appreciable enhancements were observed in the amount of H and D retained within the near-surface region of predamaged samples compared to samples with no prior damage. The total amount of D retained within the near-surface region was measured by means of the nuclear reaction D( 3 He,p) 4 He, and H depth profiles were measured via a resonance in the nuclear reaction 1 H( 19 F,αγ) 16 O. The H profiles correlate with the predicted predamaging ion profiles; however, appreciable tails to deeper depths for the hydrogen profiles are observed for the heavier predamaging ions. For a given predamage ion fluence, the amount of trapped deuterium increases linearly with incident deuterium fluence until a saturation in the enhancement is reached. The amount of deuterium trapped when saturation occurs increases with increasing predamage fluence. The experiments indicate that lighter ions, which create fewer primary displacements, are more effective per displacement in trapping hydrogen. An appreciable release of hydrogen is obtained upon annealing at 200 and 300 degreeC, and a preannealing experiment indicates this is due to detrapping rather than to any loss of traps. These temperatures suggest a much higher binding energy for the trapped hydrogen isotopes (approx.1.5 eV) than the available evidence gives for simple H-defect binding energies (approximately-less-than0.3 eV). The detailed trapping mechanism is not known. However, it is suggested on the basis of the high binding energies and the high concentrations of hydrogen which can be trapped that clusters of hydrogen may be formed

Micro structure processing on plastics by accelerated hydrogen molecular ions

Science.gov (United States)

Hayashi, H.; Hayakawa, S.; Nishikawa, H.

2017-08-01

A proton has 1836 times the mass of an electron and is the lightest nucleus to be used for accelerator in material modification. We can setup accelerator with the lowest acceleration voltage. It is preferable characteristics of Proton Beam Writer (PBW) for industrial applications. On the contrary ;proton; has the lowest charge among all nuclei and the potential impact to material is lowest. The object of this research is to improve productivity of the PBW for industry application focusing on hydrogen molecular ions. These ions are generated in the same ion source by ionizing hydrogen molecule. There is no specific ion source requested and it is suitable for industrial use. We demonstrated three dimensional (3D) multilevel micro structures on polyester base FPC (Flexible Printed Circuits) using proton, H2+ and H3+. The reactivity of hydrogen molecular ions is much higher than that of proton and coincident with the level of expectation. We can apply this result to make micro devices of 3D multilevel structures on FPC.

Study of the hydrogen behavior in amorphous hydrogenated materials of type a - C:H and a - SiC:H facing fusion reactor plasma

International Nuclear Information System (INIS)

Barbier, G.

1997-01-01

Plasma facing components of controlled fusion test devices (tokamaks) are submitted to several constraints (irradiation, high temperatures). The erosion (physical sputtering and chemical erosion) and the hydrogen recycling (retention and desorption) of these materials influence many plasma parameters and thus affect drastically the tokamak running. First, we will describe the different plasma-material interactions. It will be pointed out, how erosion and hydrogen recycling are strongly related to both chemical and physical properties of the material. In order to reduce these interactions, we have selected two amorphous hydrogenated materials (a-C:H and a-SiC:H), which are known for their good thermal and chemical qualities. Some samples have been then implanted with lithium ions at different fluences. Our materials have been then irradiated with deuterium ions at low energy. From our results, it is shown that both the lithium implantation and the use of an a - SiC:H substrate can be beneficial in enhancing the hydrogen retention. These results were completed with thermal desorption studies of these materials. It was evidenced that the hydrogen fixation was more efficient in a-SiC:H than in a-C:H substrate. Results in good agreement with those described above have been obtained by exposing a - C:H and a - SiC:H samples to the scrape off layer of the tokamak of Varennes (TdeV, Canada). A modelling of hydrogen diffusion under irradiation has been also proposed. (author)

Study on the hydrogen negative ion in low pressure discharges

International Nuclear Information System (INIS)

Bruneteau, A.M.

1983-07-01

A new use of negative hydrogen ions is the production of intense fast neutral atom beams useful in plasma heating in thermonuclear heating. That is one of the reasons that started this study. The density of negative hydrogen ions in diffusion, and multipole-type low pressure (10 -3 - 10-2 Torr) discharges is deduced from the various formation and destruction processes of the species present in these discharges. The H - ions are essentially produced by dissociative attachment to vibrationally excited molecules and destroyed by processes the relative importance of which is discussed as a function of the discharge parameters. The experimental study of the density of the H - ions, measured by photodetachment, as a function of these parameters, coroborates the theoretical model [fr

Experimental measurements of negative hydrogen ion production from surfaces

International Nuclear Information System (INIS)

Graham, W.G.

1977-09-01

Experimental measurements of the production of H - from surfaces bombarded with hydrogen are reviewed. Some measurements of H + and H 0 production from surfaces are also discussed with particular emphasis on work which might be relevant to ion source applications

Can Cu(II) ions be doped into the crystal structure of potassium hydrogen tartrate?

OpenAIRE

Srinivasan, Bikshandarkoil R.; Remesh, H.

2015-01-01

The differing binding preferences of the hydrogen tartrate ligand (HC4H4O6)- namely {\\mu}7-octadentate mode for potassium ion and bidentate mode for cupric ion rules out the doping (incorporation) of any Cu(II) ion into the crystal structure of potassium hydrogen tartrate. Hence, the claim of growth of copper doped potassium hydrogen tartrate viz. K0.96Cu0.04C4H5O6 by Mathivanan and Haris, Indian J Pure App Phys 51 (2013) 851-859 is untenable.

Study of the hydrogen behavior in amorphous hydrogenated materials of type a - C:H and a - SiC:H facing fusion reactor plasma; Etude du comportament de l`hydrogene dans des materiaux amorphes hydrogenes de type a - C:H et a - SiC:H devant faire face au plasma des reacteurs a fusion

Energy Technology Data Exchange (ETDEWEB)

Barbier, G. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire

1997-04-10

Plasma facing components of controlled fusion test devices (tokamaks) are submitted to several constraints (irradiation, high temperatures). The erosion (physical sputtering and chemical erosion) and the hydrogen recycling (retention and desorption) of these materials influence many plasma parameters and thus affect drastically the tokamak running. First, we will describe the different plasma-material interactions. It will be pointed out, how erosion and hydrogen recycling are strongly related to both chemical and physical properties of the material. In order to reduce these interactions, we have selected two amorphous hydrogenated materials (a-C:H and a-SiC:H), which are known for their good thermal and chemical qualities. Some samples have been then implanted with lithium ions at different fluences. Our materials have been then irradiated with deuterium ions at low energy. From our results, it is shown that both the lithium implantation and the use of an a - SiC:H substrate can be beneficial in enhancing the hydrogen retention. These results were completed with thermal desorption studies of these materials. It was evidenced that the hydrogen fixation was more efficient in a-SiC:H than in a-C:H substrate. Results in good agreement with those described above have been obtained by exposing a - C:H and a - SiC:H samples to the scrape off layer of the tokamak of Varennes (TdeV, Canada). A modelling of hydrogen diffusion under irradiation has been also proposed. (author) 176 refs.

A feature of negative hydrogen ion production in the Uramoto-type sheet plasma

Energy Technology Data Exchange (ETDEWEB)

Jimbo, Kouichi [Kyoto Univ., Uji (Japan). Inst. of Atomic Energy

1997-02-01

It seems that negative hydrogen ions H{sup -} are formed directly from atomic hydrogens H. When the chamber was biased more negative against the anode potential at constant are power, forming a much deeper electrostatic well in the Uramoto-type sheet plasma negative ion source, more negative hydrogen ion currents were extracted. The chamber potential V{sub B} was biased down to -100V in the 150V discharge. The negative ion current J{sup -} was evaluated by the JAERI-probe measurement. J{sup -} increases linearly with the chamber current I{sub B}. The largest J{sup -} value was obtained at absolute value of |V{sub prob,f}|=15V and absolute value of |V{sub B}|=100V; the discharge was not operated for absolute value of |V{sub B}|>100V. We speculate the following collisional (three-body) electron attachment to H as a possible production process for H{sup -}; e+e+H{yields}e+H{sup -}. This process may explain the linear increase of J{sup -} with absolute value of |V{sub prob,f}|. (S.Y.)

Negative hydrogen ion production mechanisms

Energy Technology Data Exchange (ETDEWEB)

Bacal, M. [UPMC, LPP, Ecole Polytechnique, UMR CNRS 7648, Palaiseau (France); Wada, M. [School of Science and Engineering, Doshisha University, Kyoto 610-0321 (Japan)

2015-06-15

Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

Determination of the diffusion coefficient of hydrogen ion in hydrogels.

Science.gov (United States)

Schuszter, Gábor; Gehér-Herczegh, Tünde; Szűcs, Árpád; Tóth, Ágota; Horváth, Dezső

2017-05-17

The role of diffusion in chemical pattern formation has been widely studied due to the great diversity of patterns emerging in reaction-diffusion systems, particularly in H + -autocatalytic reactions where hydrogels are applied to avoid convection. A custom-made conductometric cell is designed to measure the effective diffusion coefficient of a pair of strong electrolytes containing sodium ions or hydrogen ions with a common anion. This together with the individual diffusion coefficient for sodium ions, obtained from PFGSE-NMR spectroscopy, allows the determination of the diffusion coefficient of hydrogen ions in hydrogels. Numerical calculations are also performed to study the behavior of a diffusion-migration model describing ionic diffusion in our system. The method we present for one particular case may be extended for various hydrogels and diffusing ions (such as hydroxide) which are relevant e.g. for the development of pH-regulated self-healing mechanisms and hydrogels used for drug delivery.

Reaction of O+, CO+, and CH+ ions with atomic hydrogen

International Nuclear Information System (INIS)

Federer, W.; Villinger, H.; Howorka, F.; Lindinger, W.; Tosis, P.; Bassi, D.; Ferguson, E.

1984-01-01

Rate coefficients for reactions of the ions O + , CO + , and CH + with atomic hydrogen have been measured for the first time at 300 K. This provides basic data for the ion chemistry of planetary atmospheres, cometary atmospheres, and interstellar molecular clouds. The O + +H measurement supports quantal calculations of this reaction. The CO + +H reaction provides an example of partial spin nonconservation in a charge-transfer reaction occurring in a deep potential well. Reactions of the same ions with H 2 that have been measured elsewhere are also reported

Hydrogen retention in ion irradiated steels

International Nuclear Information System (INIS)

Hunn, J.D.; Lewis, M.B.; Lee, E.H.

1998-01-01

In the future 1--5 MW Spallation Neutron Source, target radiation damage will be accompanied by high levels of hydrogen and helium transmutation products. The authors have recently carried out investigations using simultaneous Fe/He,H multiple-ion implantations into 316 LN stainless steel between 50 and 350 C to simulate the type of radiation damage expected in spallation neutron sources. Hydrogen and helium were injected at appropriate energy and rate, while displacement damage was introduced by nuclear stopping of 3.5 MeV Fe + , 1 microm below the surface. Nanoindentation measurements showed a cumulative increase in hardness as a result of hydrogen and helium injection over and above the hardness increase due to the displacement damage alone. TEM investigation indicated the presence of small bubbles of the injected gases in the irradiated area. In the current experiment, the retention of hydrogen in irradiated steel was studied in order to better understand its contribution to the observed hardening. To achieve this, the deuterium isotope ( 2 H) was injected in place of natural hydrogen ( 1 H) during the implantation. Trapped deuterium was then profiled, at room temperature, using the high cross-section nuclear resonance reaction with 3 He. Results showed a surprisingly high concentration of deuterium to be retained in the irradiated steel at low temperature, especially in the presence of helium. There is indication that hydrogen retention at spallation neutron source relevant target temperatures may reach as high as 10%

Comparison of measured and modelled negative hydrogen ion densities at the ECR-discharge HOMER

Science.gov (United States)

Rauner, D.; Kurutz, U.; Fantz, U.

2015-04-01

As the negative hydrogen ion density nH- is a key parameter for the investigation of negative ion sources, its diagnostic quantification is essential in source development and operation as well as for fundamental research. By utilizing the photodetachment process of negative ions, generally two different diagnostic methods can be applied: via laser photodetachment, the density of negative ions is measured locally, but only relatively to the electron density. To obtain absolute densities, the electron density has to be measured additionally, which induces further uncertainties. Via cavity ring-down spectroscopy (CRDS), the absolute density of H- is measured directly, however LOS-averaged over the plasma length. At the ECR-discharge HOMER, where H- is produced in the plasma volume, laser photodetachment is applied as the standard method to measure nH-. The additional application of CRDS provides the possibility to directly obtain absolute values of nH-, thereby successfully bench-marking the laser photodetachment system as both diagnostics are in good agreement. In the investigated pressure range from 0.3 to 3 Pa, the measured negative hydrogen ion density shows a maximum at 1 to 1.5 Pa and an approximately linear response to increasing input microwave powers from 200 up to 500 W. Additionally, the volume production of negative ions is 0-dimensionally modelled by balancing H- production and destruction processes. The modelled densities are adapted to the absolute measurements of nH- via CRDS, allowing to identify collisions of H- with hydrogen atoms (associative and non-associative detachment) to be the dominant loss process of H- in the plasma volume at HOMER. Furthermore, the characteristic peak of nH- observed at 1 to 1.5 Pa is identified to be caused by a comparable behaviour of the electron density with varying pressure, as ne determines the volume production rate via dissociative electron attachment to vibrationally excited hydrogen molecules.

Quantum effects on the formation of negative hydrogen ion by polarization electron capture in partially ionized dense hydrogen plasmas

International Nuclear Information System (INIS)

Jung, Young-Dae; Kato, Daiji

2009-05-01

The quantum effects on the formation of the negative hydrogen ion (H - ) by the polarization electron capture process are investigated in partially ionized dense hydrogen plasmas. It is shown that the quantum effect strongly suppresses the electron capture radius as well as the cross section for the formation of the negative hydrogen ion. In addition, it has been found that the electron capture position is receded from the center of the projectile with decreasing the quantum effect of the plasma. (author)

Directional effect on coloration in LiF crystal by H{sup +} and H{sub 2}{sup +} ion bombardment

Energy Technology Data Exchange (ETDEWEB)

Mingle, Gan; Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Jianer, Zeng; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1997-03-01

In the present paper, the first results are reported about the coloration in LiF crystals induced by bombardments of single hydrogen ions (H{sup +}) and molecular hydrogen ions (H{sub 2}{sup +}) with the same velocity under the <100> aligned and random conditions. For the single hydrogen ion irradiation, the coloration is rather simple. The F-type color center absorption under the <100> aligned condition becomes larger than that under the random condition with the dose increase because of larger fraction of electronic energy loss under channeling condition. On the contrary, the coloration for the molecular ions does not show big channeling effect. In the low dose region some difference can be seen but the difference of coloration is not observed any more with the dose increase. The pronounced coloration for molecular ions under the channeling condition is observed in comparison with that for single ions. (author)

Electrical shielding box measurement of the negative hydrogen beam from Penning ion gauge ion source.

Science.gov (United States)

Wang, T; Yang, Z; Dong, P; long, J D; He, X Z; Wang, X; Zhang, K Z; Zhang, L W

2012-06-01

The cold-cathode Penning ion gauge (PIG) type ion source has been used for generation of negative hydrogen (H(-)) ions as the internal ion source of a compact cyclotron. A novel method called electrical shielding box dc beam measurement is described in this paper, and the beam intensity was measured under dc extraction inside an electrical shielding box. The results of the trajectory simulation and dc H(-) beam extraction measurement were presented. The effect of gas flow rate, magnetic field strength, arc current, and extraction voltage were also discussed. In conclusion, the dc H(-) beam current of about 4 mA from the PIG ion source with the puller voltage of 40 kV and arc current of 1.31 A was extrapolated from the measurement at low extraction dc voltages.

Production of hydrogen and deuterium negative ions in an electron cyclotron resonance driven plasma

Energy Technology Data Exchange (ETDEWEB)

Dougar-Jabon, V.D. [Industrial Univ. of Santander, Bucaramanga (Colombia)

2001-04-01

An electron cyclotron resonance source with driven plasma rings for hydrogen isotope ion production is studied. Extracted currents of positive and negative ions depending on gas pressure, microwave power value and extraction voltage are obtained. The study shows that the negative ion yield is an order of magnitude higher than the yield of positive particles when a driven ring is in contact with the surface of the plasma electrode. The production of negative ions of deuterium, D{sup -}, is close to the production of negative ions of light hydrogen isotope, H{sup -}. The comparison of the experimental data with the calculated ones shows that the most probable process of the H{sup -} and D{sup -} ion formation in the electron cyclotron driven plasma is dissociative attachment of electrons to molecules in high Rydberg states. For hydrogen ions and ions of deuterium, the negative current at a microwave power of 200 W through a 3-mm aperture and 8 kV extraction voltage are 4.7 mA and 3.1 mA respectively. (orig.)

Production of hydrogen and deuterium negative ions in an electron cyclotron resonance driven plasma

International Nuclear Information System (INIS)

Dougar-Jabon, V.D.

2001-01-01

An electron cyclotron resonance source with driven plasma rings for hydrogen isotope ion production is studied. Extracted currents of positive and negative ions depending on gas pressure, microwave power value and extraction voltage are obtained. The study shows that the negative ion yield is an order of magnitude higher than the yield of positive particles when a driven ring is in contact with the surface of the plasma electrode. The production of negative ions of deuterium, D - , is close to the production of negative ions of light hydrogen isotope, H - . The comparison of the experimental data with the calculated ones shows that the most probable process of the H - and D - ion formation in the electron cyclotron driven plasma is dissociative attachment of electrons to molecules in high Rydberg states. For hydrogen ions and ions of deuterium, the negative current at a microwave power of 200 W through a 3-mm aperture and 8 kV extraction voltage are 4.7 mA and 3.1 mA respectively. (orig.)

A collisional radiative model of hydrogen plasmas developed for diagnostic purposes of negative ion sources

Energy Technology Data Exchange (ETDEWEB)

Iordanova, Snejana, E-mail: snejana@phys.uni-sofia.bg; Paunska, Tsvetelina [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria)

2016-02-15

A collisional radiative model of low-pressure hydrogen plasmas is elaborated and applied in optical emission spectroscopy diagnostics of a single element of a matrix source of negative hydrogen ions. The model accounts for the main processes determining both the population densities of the first ten states of the hydrogen atom and the densities of the positive hydrogen ions H{sup +}, H{sub 2}{sup +}, and H{sub 3}{sup +}. In the calculations, the electron density and electron temperature are varied whereas the atomic and molecular temperatures are included as experimentally obtained external parameters. The ratio of the H{sub α} to H{sub β} line intensities is calculated from the numerical results for the excited state population densities, obtained as a solution of the set of the steady-state rate balance equations. The comparison of measured and theoretically obtained ratios of line intensities yields the values of the electron density and temperature as well as of the degree of dissociation, i.e., of the parameters which have a crucial role for the volume production of the negative ions.

Negative hydrogen ion beam extraction from an AC heated cathode driven Bernas-type ion source

Energy Technology Data Exchange (ETDEWEB)

Okano, Y.; Miyamoto, N.; Kasuya, T.; Wada, M.

2015-04-08

A plasma grid structure was installed to a Bernas-type ion source used for ion implantation equipment. A negative hydrogen (H{sup −}) ion beam was extracted by an AC driven ion source by adjusting the bias to the plasma grid. The extracted electron current was reduced by positively biasing the plasma grid, while an optimum plasma grid bias voltage for negative ion beam extraction was found to be positive 3 V with respect to the arc chamber. Source operations with AC cathode heating show extraction characteristics almost identical to that with DC cathode heating, except a minute increase in H{sup −} current at higher frequency of cathode heating current.

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.)

Working group report on ion-impact excitation: Recommended database for ion-impact excitation of atomic hydrogen

International Nuclear Information System (INIS)

Fritsch, W.; Olson, R.E.; Schartner, K.H.; Belkic, D.S.

1989-01-01

This report discusses (i) proton impact excitation, and (ii) excitation by ion collisions (from helium ions to iron ions) of atomic hydrogen, both for H(1s) and H(n>1), where where n = the principal quantum number, in the energy range from 1 keV/amu to 2 MeV/amu and 10 MeV/amu, respectively. For the range of ions considered, a few generic plots are given for the total cross section as a function of E/q, where E is the beam energy, for different values q (ion charge in units of proton charge) and different final principal quantum numbers. 12 refs, 3 figs

Improving corrosion resistance of magnesium-based alloys by surface modification with hydrogen by electrochemical ion reduction (EIR) and by plasma immersion ion implantation (PIII)

Energy Technology Data Exchange (ETDEWEB)

Bakkar, A. [Institut fuer Materialpruefung und Werkstofftechnik, Dr. Doelling und Dr. Neubert GmbH, Freiberger Strasse 1, 38678 Clausthal (Germany); Department of Metallurgy and Materials Engineering, Suez Canal University, P.O. Box 43721, Suez (Egypt); Neubert, V. [Institut fuer Materialpruefung und Werkstofftechnik, Dr. Doelling und Dr. Neubert GmbH, Freiberger Strasse 1, 38678 Clausthal (Germany)]. E-mail: volkmar.neubert@tu-clausthal.de

2005-05-01

Magnesium-based hydrides are well known that they have a high hydrogen-storage capacity. In this study, two different methods have been provided for hydrogen surface modification of high purity magnesium (hp Mg) and AZ91 magnesium alloy. One was electrochemical ion reduction (EIR) of hydrogen from an alkaline electrolyte on such Mg-based cathode. The other was plasma immersion ion implantation (PIII or PI{sup 3}) into Mg-based substrate. The depth profile of H-modified surfaces was described by Auger electron spectroscopy (AES) and by secondary ion mass spectrometry (SIMS) measurements. Corrosion testing was carried out in Avesta cell by potentiodynamic polarisation in chloride-containing aqueous solutions of pH 7 and pH 12. A greatly significant improvement in the corrosion resistance of H-modified surfaces was verified.

Improving corrosion resistance of magnesium-based alloys by surface modification with hydrogen by electrochemical ion reduction (EIR) and by plasma immersion ion implantation (PIII)

International Nuclear Information System (INIS)

Bakkar, A.; Neubert, V.

2005-01-01

Magnesium-based hydrides are well known that they have a high hydrogen-storage capacity. In this study, two different methods have been provided for hydrogen surface modification of high purity magnesium (hp Mg) and AZ91 magnesium alloy. One was electrochemical ion reduction (EIR) of hydrogen from an alkaline electrolyte on such Mg-based cathode. The other was plasma immersion ion implantation (PIII or PI 3 ) into Mg-based substrate. The depth profile of H-modified surfaces was described by Auger electron spectroscopy (AES) and by secondary ion mass spectrometry (SIMS) measurements. Corrosion testing was carried out in Avesta cell by potentiodynamic polarisation in chloride-containing aqueous solutions of pH 7 and pH 12. A greatly significant improvement in the corrosion resistance of H-modified surfaces was verified

Comparison of measured and modelled negative hydrogen ion densities at the ECR-discharge HOMER

Energy Technology Data Exchange (ETDEWEB)

Rauner, D.; Kurutz, U.; Fantz, U. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany)

2015-04-08

As the negative hydrogen ion density n{sub H{sup −}} is a key parameter for the investigation of negative ion sources, its diagnostic quantification is essential in source development and operation as well as for fundamental research. By utilizing the photodetachment process of negative ions, generally two different diagnostic methods can be applied: via laser photodetachment, the density of negative ions is measured locally, but only relatively to the electron density. To obtain absolute densities, the electron density has to be measured additionally, which induces further uncertainties. Via cavity ring-down spectroscopy (CRDS), the absolute density of H{sup −} is measured directly, however LOS-averaged over the plasma length. At the ECR-discharge HOMER, where H{sup −} is produced in the plasma volume, laser photodetachment is applied as the standard method to measure n{sub H{sup −}}. The additional application of CRDS provides the possibility to directly obtain absolute values of n{sub H{sup −}}, thereby successfully bench-marking the laser photodetachment system as both diagnostics are in good agreement. In the investigated pressure range from 0.3 to 3 Pa, the measured negative hydrogen ion density shows a maximum at 1 to 1.5 Pa and an approximately linear response to increasing input microwave powers from 200 up to 500 W. Additionally, the volume production of negative ions is 0-dimensionally modelled by balancing H{sup −} production and destruction processes. The modelled densities are adapted to the absolute measurements of n{sub H{sup −}} via CRDS, allowing to identify collisions of H{sup −} with hydrogen atoms (associative and non-associative detachment) to be the dominant loss process of H{sup −} in the plasma volume at HOMER. Furthermore, the characteristic peak of n{sub H{sup −}} observed at 1 to 1.5 Pa is identified to be caused by a comparable behaviour of the electron density with varying pressure, as n{sub e} determines

An overview of negative hydrogen ion sources for accelerators

Science.gov (United States)

Faircloth, Dan; Lawrie, Scott

2018-02-01

An overview of high current (>1 mA) negative hydrogen ion (H-) sources that are currently used on particle accelerators. The current understanding of how H- ions are produced is summarised. Issues relating to caesium usage are explored. The different ways of expressing emittance and beam currents are clarified. Source technology naming conventions are defined and generalised descriptions of each source technology are provided. Examples of currently operating sources are outlined, with their current status and future outlook given. A comparative table is provided.

The charge spectrum of positive ions in a hydrogen aurora

Science.gov (United States)

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

1976-01-01

An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

XUV-exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets. Part II: hydrogen coronae and ion escape.

Science.gov (United States)

Kislyakova, Kristina G; Lammer, Helmut; Holmström, Mats; Panchenko, Mykhaylo; Odert, Petra; Erkaev, Nikolai V; Leitzinger, Martin; Khodachenko, Maxim L; Kulikov, Yuri N; Güdel, Manuel; Hanslmeier, Arnold

2013-11-01

We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a "super-Earth" with a radius of 2 R(Earth) and a mass of 10 M(Earth), located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×10²⁵ s⁻¹ to ∼5.3×10³⁰ s⁻¹, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EO(H)) to <3 EO(H) and usually is several times smaller in comparison to the thermal atmospheric escape rates.

Experimental study on negative hydrogen ion formation in the quiescent plasma machine at INPE

International Nuclear Information System (INIS)

Ferreira, J.L.; Ferreira, J.G.; Damasio, W.C.

1989-01-01

The preliminary results from the study on generation of positive and negative hydrogen ions in plasma produced by thermionic discharge confined superficially by magnetic fields, are presented. In the interior of this discharge was inserted a Langmuir electrostatic probe to measure H - , H + , H + 2 and H + 3 concentrations in the plasma produced from argon (Ar) and hydrogen (H 2 ) gas mixture. (M.C.K.) [pt

Investigation of the hydrogen multilayered target H/T-D{sub 2} and muonic X-ray yields in ion implantation

Energy Technology Data Exchange (ETDEWEB)

Gheisari, R., E-mail: gheisari@pgu.ac.ir [Physics Department, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of)

2011-12-21

This paper extends applications of the multilayered solid target H/T-D{sub 2}, which is kept at 3 K. The time evolutions of muonic tritium atoms ({mu}t) are obtained, by taking into account {mu}t production rate at different places of deuterium material. The apparatus H/T-D{sub 2} can be used for checking nuclear properties of implanted ions, which take part at muon transfer. Electromagnetic X-rays are generated by muon atomic transitions. The muonic X-ray transition energies are strongly affected by the size of nuclei. Here, a solid hydrogen-tritium (H/T) with a Almost-Equal-To 1 mm thick is used for {mu}t production. For ion implantation, the required amount of deuterium material is determined to be about 3.2 {mu}m. Moreover, the muonic X-ray yields are estimated and compared with those of the arrangement H/T-D{sub 2}. While the present target requires argon ion beam intensity nearly a factor of 2 times smaller; gives a relatively higher X-ray yield (15% enhancement per hour) at the energy 644 keV with the detection efficiency of Almost-Equal-To 1%.

Sensitive detection of hydrogen in a-Si:H by coincidence measurement of elastically scattered 100 MeV /sup 3/He/sup 2 +/ ions and recoil protons

Energy Technology Data Exchange (ETDEWEB)

Fukada, Noboru; Imura, Takeshi; Hiraki, Akio [Osaka Univ., Suita (Japan). Faculty of Engineering; Itahashi, Takahisa; Fukuda, Tomokazu; Tanaka, Masayoshi

1982-09-01

We have drastically improved the sensitivity of the nuclear elastic scattering (NES) method for determining hydrogen concentrations in hydrogenated amorphous silicon (a-Si:H) films. A beam of 100 MeV /sup 3/He/sup 2 +/ ions was used in the experiment. By taking the coincidence of detection of the scattered /sup 3/He ion with that of the recoil proton, we could achieve a sensitivity of 0.1 atomic percent with a precision of about 1 percent for 1 ..mu..m films.

Collisional excitation of ArH+ by hydrogen atoms

Science.gov (United States)

Dagdigian, Paul J.

2018-06-01

The rotational excitation of the 36ArH+ ion in collisions with hydrogen atoms is investigated in this work. The potential energy surface (PES) describing the 36ArH+-H interaction, with the ion bond length r fixed at the average of r over the radial v = 0 vibrational state distribution, was obtained with a coupled cluster method that included single, double, and (perturbatively) triple excitations [RCCSD(T)]. A deep minimum (De = 3135 cm-1) in the PES was found in linear H-ArH+ geometry at an ion-atom separation Re = 4.80a0. Energy-dependent cross-sections and rate coefficients as a function of temperature for this collision pair were computed in close-coupling (CC) calculations. Since the PES possesses a deep well, this is a good system to test the performance of the quantum statistical (QS) method developed by Manolopoulos and co-workers as a more efficient method to compute the cross-sections. Good agreement was found between rate coefficients obtained by the CC and QS methods at several temperatures. In a simple application, the excitation of ArH+ is simulated for conditions under which this ion is observed in absorption.

Effect of heating on the behaviors of hydrogen in C-TiC films with auger electron spectroscopy and secondary ion mass spectroscopy analyses

International Nuclear Information System (INIS)

Zou, Y.; Wang, L.W.; Huang, N.K.

2007-01-01

C-TiC films with a content of 75% TiC were prepared with magnetron sputtering deposition followed by Ar + ion bombardment. Effect of heating on the behaviors of hydrogen in C-TiC films before and after heating was studied with Auger Electron Spectroscopy and Secondary Ion Mass Spectroscopy (SIMS) analyses. SIMS depth profiles of hydrogen after H + ion implantation and thermal treatment show different hydrogen concentrations in C-TiC coatings and stainless steel. SIMS measurements show the existence of TiH, TiH 2 , CH 3 , CH 4 , C 2 H 2 bonds in the films after H + ion irradiation and the changes in the Ti LMM, Ti LMV and C KLL Auger line shape reveal that they have a good hydrogen retention ability after heating up to the temperature 393 K. All the results show that C-TiC coatings can be used as a hydrogen retainer or hydrogen permeable barrier on stainless steel to protect it from hydrogen brittleness

Hydrogen ion (Ph), ammonia, dissolved oxygen and nitrite ...

African Journals Online (AJOL)

Hydrogen ion (pH), dissolved oxygen, ammonia and nitrite concentrations were studied monthly in two systems (re-circulatory and semi-intensive of 3 m2 sizes) each for six months. The systems were each stocked with 200 g of Clarias gariepinus fingerlings. Results showed that all parameters were within acceptable limits ...

Correlation of H- production and the work function of a surface in a hydrogen plasma

International Nuclear Information System (INIS)

Wada, M.

1983-01-01

Surface-plasma negative hydrogen ion sources are being developed as possible parts for future netural beam systems. In these ion sources, negative hydrogen ions (H - ) are produced at low work function metal surfaces immersed in hydrogen plasmas. To investigate the correlation between the work function and the H-production at the surface with a condition similar to the one in the actual plasma ion source, these two parameters were simultaneously measured in the hydrogen plasma environment. The photoelectron emission currents from Mo and Cu surfaces in a cesiated hydrogen discharge were measured in the photon energy range from 1.45 to 4.14 eV, to determine the work function based on Fowler's theory. A small magnetic line cusp plasma container was specially designed to minimize the plasma noise and to realize the efficient collection of incident light onto the target. The photelectron current was detected phase sensitively and could be measured with reasonable accuracy up to about 5 x 10 11 cm -3 of the plasma electron density. As Cs density was increased in the hydrogen discharge, the work function decreased until it reached a minimum value. This value of the lowest work function was approximately 1.4 eV for both Mo and Cu surfaces, and the detected total H - current was a maximum at this condition

Applications of heavy-ion reactions on hydrogen isotopes

International Nuclear Information System (INIS)

Evers, E.J.

1987-01-01

This thesis describes various aspects of 'inverse' reactions between the lightest nuclides, hydrogen and deuterium, and heavy ions in the range from carbon to phosphorus. The reactions studied in this thesis always result in one light ejectile and one excited heavy nucleus. Coincidence experiments have been performed in which both the emitted light particle and the gamma radiation emitted by the excited heavy nucleus produced, are detected. Ch. 1 describes the system built for the acquisition of data obtained in such coincidence experiments. Ch. 2 describes precision measurements of nuclear lifetimes and stopping powers. Coincident Doppler shift attenuation (DSA) experiments were performed with the reaction 2 H( 31 P,pγ) 32 P at E( 31 P 7+ )=50 MeV and thin Ti 2 H targets on Au, Ag and Cu backings. Mean lifetimes of the E x =513, 1150, 1323 and 1755 levels were determined with experimental stopping powers of Forster et al. These lifetimes were used as input in further analysis of the experimental data and of an additional experiment with a target on Mg backing to determine a consistent set of stopping power data for P ions with a velocity in the range 0-8(c/137) in the four materials mentioned. Ch.'s 3 and 4 deal with narrow resonances in reactions of nitrogen and fluorine beams with hydrogen targets. In Ch. 3 a method is described for the calibration of analyzing-magnet systems of heavy-ions accelerators. Ch. 4 describes an experiment to investigate the hydrogen concentration in silicon nitride films using a resonant inverse nuclear reaction. This method turns out to be a very suitable one for determining hydrogen concentration profiles with a good depth resolution over a large depth. 69 refs.; 23 figs.; 7 tabs

Hydrogen molecular ions for improved determination of fundamental constants

NARCIS (Netherlands)

Karr, J.-P.; Hilico, L.; Koelemeij, J.C.J.; Korobov, V.I.

2016-01-01

The possible use of high-resolution rovibrational spectroscopy of the hydrogen molecular ions H-2(+) and HD+ for an independent determination of several fundamental constants is analyzed. While these molecules had been proposed for the metrology of nuclear-to-electron mass ratios, we show that they

Electron capture by C2+ and Ti2+ ions in H and H2

International Nuclear Information System (INIS)

Nutt, W.L.; McCullough, R.W.; Gilbody, H.B.

1978-01-01

Cross sections for electron capture by C 2+ and Ti 2+ ions in H and H 2 have been determined within the energy range 0.5 to 14 keV from measurements made using a tungsten-tube furnace to provide a target of highly dissociated hydrogen. (author)

Influence of hydrogen-ion concentration exponent on undrained shear behaviour of bentonites; Bentonaito no hihaisui sendan kyodo ni oyobosu suiso ion nodo shisu no eikyo

Energy Technology Data Exchange (ETDEWEB)

Kamei, T [Kiso Jiban Consultants Co. Ltd., Tokyo (Japan); Tokida, M [Nagano National College of Technology, Nagano (Japan)

1994-12-21

Because there is a report example that the yield stress of a landslide clay increases along with a decrease of a hydrogen-ion concentration exponent, it is thought that a shear strength of the landslide clay depends on the hydrogen-ion concentration exponent. Furthermore, when the soil stabilization method by lime is applied to the soft ground and high organic earth, it is pointed out that the hydrogen-ion concentration exponent will become one of the harmful factors. Accordingly, it is understood that revealing an influence of a hydrogen-ion concentration exponent affects on the characteristics of an earth is one of the important factors, to evaluate a strength, deformation and so forth of the viscous ground. In this study, in order to examine an influence of a hydrogen-ion concentration exponent affecting on an undrained shear behavior of the bentonites, for the artificially adjusted bentonite specimens with 5 kinds of different pH, the isotropic consolidated undrained triaxial compression tests were performed, and consequently an influence of pH affecting on the engineering characteristics of the bentonites was made clear quantitatively. 28 refs., 16 figs., 5 tabs.

Silicon surface damage caused by reactive ion etching in fluorocarbon gas mixtures containing hydrogen

International Nuclear Information System (INIS)

Norstroem, H.; Blom, H.; Ostling, M.; Nylandsted Larsen, A.; Keinonen, J.; Berg, S.

1991-01-01

For selective etching of SiO 2 on silicon, gases or gas mixtures containing hydrogen are often used. Hydrogen from the glow discharge promotes the formation of a thin film polymer layer responsible for the selectivity of the etching process. The reactive ion etch (RIE) process is known to create damage in the silicon substrate. The influence of hydrogen on the damage and deactivation of dopants is investigated in the present work. The distribution of hydrogen in silicon, after different etching and annealing conditions have been studied. The influence of the RIE process on the charge carrier concentration in silicon has been investigated. Various analytical techniques like contact resistivity measurements, four point probe measurements, and Hall measurements have been used to determine the influence of the RIE process on the electrical properties of processed silicon wafers. The hydrogen profile in as-etched and post annealed wafers was determined by the 1 H( 15 N,αγ) 12 C nuclear reaction. The depth of the deactivated surface layer is discussed in terms of the impinging hydrogen ion energy, i.e., the possibility of H + ions to pick up an energy equal to the peak-to-peak voltage of the rf signal

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

Science.gov (United States)

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

2015-07-01

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

Note: Recombination of H+ and OH− ions along water wires

International Nuclear Information System (INIS)

Lee, Song Hi; Rasaiah, Jayendran C.

2013-01-01

Transport and recombination of hydrogen and hydroxide ions along a hydrogen-bonded water wire are studied by molecular dynamics simulation using a dissociating model for water. The results are compared with a recent CP-MD study of neutralization in bulk water [A. Hassanali, M. K. Prakrash, H. Eshet, and M. Parrinello, Proc. Natl. Acad. Sci. U.S.A. 108, 20410 (2011)]. The translocation of H + and OH − along the wire is faster than in the bulk water, followed by compression of the water wire when two water molecules separate the transported ions. Neutralization occurs with the concerted transfer of three protons as in the bulk water, followed by energy dissipation along the water chain

Plasma-surface interaction in negative hydrogen ion sources

Science.gov (United States)

Wada, Motoi

2018-05-01

A negative hydrogen ion source delivers more beam current when Cs is introduced to the discharge, but a continuous operation of the source reduces the beam current until more Cs is added to the source. This behavior can be explained by adsorption and ion induced desorption of Cs atoms on the plasma grid surface of the ion source. The interaction between the ion source plasma and the plasma grid surface of a negative hydrogen ion source is discussed in correlation to the Cs consumption of the ion source. The results show that operation with deuterium instead of hydrogen should require more Cs consumption and the presence of medium mass impurities as well as ions of the source wall materials in the arc discharge enlarges the Cs removal rate during an ion source discharge.

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.

Influence of nonionic surfactants on the potentiometric response of hydrogen ion-selective polymeric membrane electrodes.

Science.gov (United States)

Espadas-Torre, C; Bakker, E; Barker, S; Meyerhoff, M E

1996-05-01

The influence of poly(ethylene oxide)-based nonionic surfactants (i.e., Triton X-100 and Brij 35) in the sample phase on the response properties of hydrogen ion-selective polymeric membrane electrodes containing mobile (lipophilic amines) or covalently bound (aminated-poly-(vinyl chloride)) hydrogen ion carriers is reported. In the presence of these nonionic surfactants, membrane electrode response toward interfering cation activity (e.g., Na+) in the sample phase is increased substantially and the pH measuring range shortened. The degree of cation interference for pH measurements is shown to correlate with the basicity of the hydrogen ion carrier doped within the membrane phase. The observed deterioration in selectivity arises from the partitioning of the surfactant into the membrane and concomitant extraction of metal cations by the surfactants in the organic phase. The effect of nonionic surfactants on pH electrodes prepared with aminated-PVC membranes is shown to be more complex, with additional large shifts in EMF values apparently arising from multidentate interactions between the surfactant molecules and the polymeric amine in the membrane, leading to a change in the apparent pKa values for the amine sites. The effects induced by nonionic surfactants on the EMF response function of hydrogen ion-selective polymeric membrane electrodes are modeled, and experimental results are shown to correlate well with theoretical predictions.

Calculation of von Neumann entropy for hydrogen and positronium negative ions

International Nuclear Information System (INIS)

Lin, Chien-Hao; Ho, Yew Kam

2014-01-01

In the present work, we carry out calculations of von Neumann entropies and linear entropies for the hydrogen negative ion and the positronium negative ion. We concentrate on the spatial (electron–electron orbital) entanglement in these ions by using highly correlated Hylleraas functions to represent their ground states, and to take care of correlation effects. We apply the Schmidt decomposition method on the partial-wave expanded two-electron wave functions, and from which the one-particle reduced density matrix can be obtained, leading to the quantifications of linear entropy and von Neumann entropy in the H − and Ps − ions. - Highlights: • We calculate von Neumann entropies and linear entropies for hydrogen and positronium negative ions. • We employ highly correlated Hylleraas functions to take into account of correlation effects. • Spatial (electron–electron orbital) entanglement is quantified using the Schmidt decomposition method. • The eigenvalues of the one-particle reduced density matrix are calculated

Charge changing and excitation cross sections for 1-25 KeV hydrogen ions and atoms incident on sodium

International Nuclear Information System (INIS)

Howald, A.M.

1983-01-01

Measurements of charge changing and excitation cross sections for 1-25 keV beams of hydrogen atoms and ions incident on a sodium vapor target are reported. The charge changing cross sections are for reactions in which the incident H ion or atom gains or loses an electron during a collision with a Na atoms to form a hydrogen ion or atom in a different charge state. The six cross sections measured are sigma/sub +0/ and sigma/sub +-/ for incident protons, sigma/sub -0/ and sigma/sub -+/ for incident H - ions, and sigma/sub g-/ and sigma/sub g+/ for incident H(1s) atoms. Measurements are also reported for the negative, neutral, and positve equilibrium fractions for H beams in thick Na targets. The excitation cross sections are for reactions in which the Na target atom is excited to the 3p level by a collision with a H atom or ion. The five cross sections measured are for incident H + , H 2 + , H 3 + , and H - ions, and for H(1s) atoms. These cross sections are measured using a new technique that compares them directly to the known cross section for excitation by electron impact

Interaction of He+2 ions with hydrogen molecules

International Nuclear Information System (INIS)

Afrosimov, V.V.; Leiko, G.A.; Panov, M.N.

1980-01-01

Cross sections for all elementary reactions involving a change in charge state in He +2 -H 2 collisions have been measured for He +2 kinetic energies in the range E=1.2--100 keV. Measurements were carried out by distinguishing an individual collision by a coincidence method and by simultaneously analyzing the charge states of the fast and slow particles. Furthermore, in the same event, the electronic states of the particles after the collision were determined by analyzing the kinetic energies of the resulting ions. The elementary reactions involving the formation of He + ions in the ground and excited states were studied. The reactions involving transitions in the hydrogen molecule to the 1ssigma/sub g/ and 2psigma/sub u/ states of H 2 + ions, and reactions in which wto protons are formed, were also studied. At E>15 keV, the largest cross section is that corresponding to one-electron capture: He +2 +H 2 →He + +H 2 + (this cross section is sigma=8.3 x 10 -16 cm 2 at E=50 keV). In this reaction, 90--98% of the He + ions are formed in excited states with principal quantum number n=2. At E + ion predominates, accompanied by the simultaneous dissociation of the H 2 + ion: He +2 +H 2 →He + (1s)+H + H+H0+e - . The cross section for this exothermic capture with dissociation (the energy released is ΔEapprox. =+36.3--3.8 eV) increases with decreasing energy E. At E>15 keV, an endothermic pathway is predominant: →He + (2s,2p)+H + +H+0+e - (the energy expended, ΔE, is more than 3.2 eV). The existence of two capture reactions with dissociation - exothermic and endothermic - leads to a minimum in the cross section for this reaction, at Eapprox. =15 keV. Ionization reactions and ionization with dissociation have the smallest cross sections

Experimental investigation of the formation of negative hydrogen ions in collisions between positive ions and atomic or molecular targets

International Nuclear Information System (INIS)

Lattouf, Elie

2013-01-01

The formation of the negative hydrogen ion (H - ) in collisions between a positive ion and a neutral atomic or molecular target is studied experimentally at impact energies of a few keV. The doubly-differential cross sections for H - formation are measured as a function of the kinetic energy and emission angle for the collision systems OH + + Ar and O + + H 2 O at 412 eV/a.m.u. These H - ions can be emitted at high energies (keV) in hard quasi-elastic two-body collisions involving a large momentum transfer to the H center. However, H - anions are preferentially emitted at low energy (eV) due to soft many-body (≥ 2) collisions resulting in a low momentum transfer. The formation of H - ions by electron capture follows excitation or ionization of the molecule. The molecular fragmentation dynamics is modeled to simulate the emission of H - ions. The overall good agreement between the simulation and the experiment leads to the understanding of most of the experimental observations. (author) [fr

Determination of Hydrogen Density by Swift Heavy Ions.

Science.gov (United States)

Xu, Ge; Barriga-Carrasco, M D; Blazevic, A; Borovkov, B; Casas, D; Cistakov, K; Gavrilin, R; Iberler, M; Jacoby, J; Loisch, G; Morales, R; Mäder, R; Qin, S-X; Rienecker, T; Rosmej, O; Savin, S; Schönlein, A; Weyrich, K; Wiechula, J; Wieser, J; Xiao, G Q; Zhao, Y T

2017-11-17

A novel method to determine the total hydrogen density and, accordingly, a precise plasma temperature in a lowly ionized hydrogen plasma is described. The key to the method is to analyze the energy loss of swift heavy ions interacting with the respective bound and free electrons of the plasma. A slowly developing and lowly ionized hydrogen theta-pinch plasma is prepared. A Boltzmann plot of the hydrogen Balmer series and the Stark broadening of the H_{β} line preliminarily defines the plasma with a free electron density of (1.9±0.1)×10^{16}  cm^{-3} and a free electron temperature of 0.8-1.3 eV. The temperature uncertainty results in a wide hydrogen density, ranging from 2.3×10^{16} to 7.8×10^{18}  cm^{-3}. A 108 MHz pulsed beam of ^{48}Ca^{10+} with a velocity of 3.652  MeV/u is used as a probe to measure the total energy loss of the beam ions. Subtracting the calculated energy loss due to free electrons, the energy loss due to bound electrons is obtained, which linearly depends on the bound electron density. The total hydrogen density is thus determined as (1.9±0.7)×10^{17}  cm^{-3}, and the free electron temperature can be precisely derived as 1.01±0.04  eV. This method should prove useful in many studies, e.g., inertial confinement fusion or warm dense matter.

A hydrogen-ferric ion rebalance cell operating at low hydrogen concentrations for capacity restoration of iron-chromium redox flow batteries

Science.gov (United States)

Zeng, Y. K.; Zhao, T. S.; Zhou, X. L.; Zou, J.; Ren, Y. X.

2017-06-01

To eliminate the adverse impacts of hydrogen evolution on the capacity of iron-chromium redox flow batteries (ICRFBs) during the long-term operation and ensure the safe operation of the battery, a rebalance cell that reduces the excessive Fe(III) ions at the positive electrolyte by using the hydrogen evolved from the negative electrolyte is designed, fabricated and tested. The effects of the flow field, hydrogen concentration and H2/N2 mixture gas flow rate on the performance of the hydrogen-ferric ion rebalance cell have been investigated. Results show that: i) an interdigitated flow field based rebalance cell delivers higher limiting current densities than serpentine flow field based one does; ii) the hydrogen utilization can approach 100% at low hydrogen concentrations (≤5%); iii) the apparent exchange current density of hydrogen oxidation reaction in the rebalance cell is proportional to the square root of the hydrogen concentration at the hydrogen concentration from 1.3% to 50%; iv) a continuous rebalance process is demonstrated at the current density of 60 mA cm-2 and hydrogen concentration of 2.5%. Moreover, the cost analysis shows that the rebalance cell is just approximately 1% of an ICRFB system cost.

Optimum extracted H- and D- current densities from gas-pressure-limited high-power hydrogen/deuterium tandem ion sources

International Nuclear Information System (INIS)

Hiskes, J.R.

1993-01-01

The tandem hydrogen/deuterium ion source is modelled for the purpose of identifying the maximum current densities that can be extracted subject to the gas-pressure constraints proposed for contemporary beam-line systems. Optimum useful extracted current densities are found to be in the range of approximately 7 to 10 mA cm -2 . The sensitivity of these current densities is examined subject to uncertainties in the underlying atomic/molecular rate processes; A principal uncertainty remains the quantification of the molecular vibrational distribution following H 3 + wall collisions

Secondary Electron Emission from Solid Hydrogen and Deuterium Resulting from Incidence of keV Electrons and Hydrogen Ions

DEFF Research Database (Denmark)

Sørensen, H.

1977-01-01

are small, in contrast to what is expected for insulating materials. One explanation is that the secondary electrons lose energy inside the target material by exciting vibrational and rotational states of the molecules, so that the number of electrons that may escape as secondary electrons is rather small....... The losses to molecular states will be largest for hydrogen, so that the SEE coefficients are smallest for solid hydrogen, as was observed. For the incidence of ions, the values of δ for the different molecular ions agree when the number of secondary electrons per incident atom is plotted versus the velocity...... or the stopping power of the incident particles. Measurements were also made for oblique incidence of H+ ions on solid deuterium for angles of incidence up to 75°. A correction could be made for the emission of secondary ions by also measuring the current calorimetrically. At largest energies, the angular...

The Cascaded Arc: High Flows of Rovibrationally Excited H2 and its Impact on H- Ion Formation

International Nuclear Information System (INIS)

Gabriel, O.; Harskamp, W. E. N. van; Schram, D. C.; Sanden, M. C. M. van de; Engeln, R.

2009-01-01

The cascaded arc is a plasma source providing high fluxes of excited and reactive species such as ions, radicals and rovibrationally excited molecules. The plasma is produced under pressures of some kPa in a direct current arc with electrical powers up to 10 kW. The plasma leaves the arc channel through a nozzle and expands with supersonic velocity into a vacuum-chamber kept by pumps at low pressures. We investigated the case of a pure hydrogen plasma jet with and without an applied axial magnetic field that confines ions and electrons in the jet. Highly excited molecules and atoms were detected by means of laser-induced fluorescence and optical emission spectroscopy. In case of an applied magnetic field the atomic state distribution of hydrogen atoms shows an overpopulation between the electronic states p = 5, 4 and 3. The influence of the highly excited hydrogen molecules on H - ion formation and a possible mechanism involving this negative ion and producing atomic hydrogen in state p = 3 will be discussed.

Hydrogen/deuterium exchange of multiply-protonated cytochrome c ions

International Nuclear Information System (INIS)

Wood, T.D.; Guan, Ziqiang; O'Connor, P.B.

1995-01-01

Low resolution measurements show gaseous multiply-protonated cytochrome c ions undergo hydrogen/deuterium (H/D) exchange with pseudo first-order kinetics at three distinct exchange levels, suggesting the co-existence of gaseous protein conformations. Although exchange levels first increase with increasing charge values, they decrease at the highest charge values, consistent with solution-phase behavior of cytochrome c, where the native structure unfolds with decreasing pH until folding into a compact A-state at lowest pH. High resolution measurements indicate the presence of at least six H/D exchange levels. Infrared (IR) laser heating and fast collisions via quadrupolar excitation (QE) increase H/D exchange levels (unfolding) while charge-stripping ions to lower charge values can increase or decrease H/D exchange levels (unfolding or folding). Wolynes has suggested studying proteins in vacuo could play an important role in delineating the contributions various forces play in the protein folding process, provided appropriate comparisons can be made between gas-phase and solution-phase structures

Electron cyclotron resonance discharge as a source for hydrogen and deuterium ions production

Energy Technology Data Exchange (ETDEWEB)

Chacon Velasco, A.J. [Universidad de Pamplona, Pamplona (Colombia); Dougar-Jabon, V.D. [Universidad Industrial de Santander, Bucaramanga (Colombia)

2004-07-01

In this report, we describe characteristics of a ring-structure hydrogen plasma heated in electron cyclotron resonance conditions and confined in a mirror magnetic trap and discuss the relative efficiency of secondary electrons and thermo-electrons in negative hydrogen and deuterium ion production. The obtained data and calculations of the balance equations for possible reactions demonstrate that the negative ion production is realized in two stages. First, the hydrogen and deuterium molecules are excited in collisions with the plasma electrons to high-laying Rydberg or vibrational levels in the plasma volume. The second stage leads to the negative ion production through the process of dissociative attachment of low energy electrons. The low energy electrons are originated due to a bombardment of the plasma electrode by ions of one of the driven rings and thermo-emission from heated tungsten filaments. Experiments seem to indicate that the negative ion generation occurs predominantly in the limited volume filled with thermo-electrons. Estimation of the negative ion generation rate shows that the main channel of H{sup -} and D{sup -} ion production involves the process of high Rydberg state excitation. (authors)

Electron cyclotron resonance discharge as a source for hydrogen and deuterium ions production

International Nuclear Information System (INIS)

Chacon Velasco, A.J.; Dougar-Jabon, V.D.

2004-01-01

In this report, we describe characteristics of a ring-structure hydrogen plasma heated in electron cyclotron resonance conditions and confined in a mirror magnetic trap and discuss the relative efficiency of secondary electrons and thermo-electrons in negative hydrogen and deuterium ion production. The obtained data and calculations of the balance equations for possible reactions demonstrate that the negative ion production is realized in two stages. First, the hydrogen and deuterium molecules are excited in collisions with the plasma electrons to high-laying Rydberg or vibrational levels in the plasma volume. The second stage leads to the negative ion production through the process of dissociative attachment of low energy electrons. The low energy electrons are originated due to a bombardment of the plasma electrode by ions of one of the driven rings and thermo-emission from heated tungsten filaments. Experiments seem to indicate that the negative ion generation occurs predominantly in the limited volume filled with thermo-electrons. Estimation of the negative ion generation rate shows that the main channel of H - and D - ion production involves the process of high Rydberg state excitation. (authors)

XPS study of the ultrathin a-C:H films deposited onto ion beam nitrided AISI 316 steel

International Nuclear Information System (INIS)

Meskinis, S.; Andrulevicius, M.; Kopustinskas, V.; Tamulevicius, S.

2005-01-01

Effects of the steel surface treatment by nitrogen ion beam and subsequent deposition of the diamond-like carbon (hydrogenated amorphous carbon (a-C:H) and nitrogen doped hydrogenated amorphous carbon (a-CN x :H)) films were investigated by means of the X-ray photoelectron spectroscopy (XPS). Experimental results show that nitrogen ion beam treatment of the AISI 316 steel surface even at room temperature results in the formation of the Cr and Fe nitrides. Replacement of the respective metal oxides by the nitrides takes place. Formation of the C-N bonds was observed for both ultrathin a-C:H and ultrathin a-CN x :H layers deposited onto the nitrided steel. Some Fe and/or Cr nitrides still were presented at the interface after the film deposition, too. Increased adhesion between the steel substrate and hydrogenated amorphous carbon layer after the ion beam nitridation was explained by three main factors. The first two is steel surface deoxidisation/passivation by nitrogen as a result of the ion beam treatment. The third one is carbon nitride formation at the nitrided steel-hydrogenated amorphous carbon (or a-CN x :H) film interface

Absorption of hydrogen in vanadium, enhanced by ion bombardment; Ionenbeschussunterstuetzte Absorption des Wasserstoffs in Vanadium

Energy Technology Data Exchange (ETDEWEB)

Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

1998-12-31

Prior to hydrogen implantation into vanadium, the vanadium specimen usually is exposed to an activation process and is then heated at 1 atm hydrogen to temperatures between 500 and 600 C, subsequently cooled down in several steps. Within this temperature range, hydrogen solubility increases with declining temperature. A decisive factor determining hydrogen absorption is the fact that at temperatures above 250 C, oxygen desorbs from the material surface and thus no longer inhibits hydrogen absorption. Therefore a different approach was chosen for the experiments reported: Hydrogen absorption under UHV conditions at room temperature. After the usual activation process, the vanadium surface was cleaned by 5 keV Ar{sup +} ion bombardment. Thus oxygen absorption at the specimen surface (and new reactions with oxygen from the remaining gas) could be avoided, or removed. By means of thermal desorption mass spectrometry (TDMS), hydrogen absorption as a function of argon ion dose was analysed. TDMS measurements performed for specimens treated by ion bombardment prior to H{sup 2} exposure showed two H{sup 2} desorption peaks, in contrast to the profiles measured with specimens not exposed to ion bombardment. It is assumed that the ion bombardment disturbs the crystal structure so that further sites for hydrogen absorption are produced. (orig./CB) [Deutsch] Bei der Beladung von Vandium mit Wasserstoff wird ueblicherweise die Probe nach einer Aktivierungsprozedur bei 1 atm Wasserstoff auf Temperaturen im Bereich von 500 bis 600 C hochgeheizt und danach schrittweise abgekuehlt. In diesem Temperaturbereich nimmt die Wasserstoffloeslichkeit mit abnehmender Temperatur zu. Entscheidend fuer die Beladung ist aber auch die Tatsache, dass bei Temperaturen groesser 250 C Sauerstoff von der Oberflaeche desorbiert und dadurch die Absorption von Wasserstoff nicht mehr blockieren kann. Im Rahmen der hier beschriebenen Untersuchungen sollte die Wasserstoffbeladung unter UHV-Bedingungen bei

Assessment for ion beam analysis methods about hydrogen isotope in hydrogen storaged metal

International Nuclear Information System (INIS)

Ding Wei; Long Xinggui; Shi Liqun

2006-01-01

In this paper, experimental arrangements of measuring hydrogen isotope concentration and distribution in metal hydride with ion beam analysis methods were reported, and the advantage and disadvantage of different methods were analyzed too. Experiment results show that it can get abundant information and accurate value by these ways. It can get an accurate value since it's the Rutherford cross-section, and the Mylar film used in the experiment is thin enough for H, D and T distinguishing each other while using ERD analysis method with 6.0 MeV O ion beam to proceed this work, but the disadvantage of this method is that the sample preparing is more difficult, and the analysis depth is lower. It could get the distribution information of H, D and T and the analysis depth is about 3.0 μm while using ERD analysis method with 7.4 MeV 4 He ion beam, but the disadvantage is that the spectra of H, D and T overlap each other, which makes a big error in simulated calculation. If using PBS method with 3.0 MeV proton, the analysis depth is deeper, but it couldn't get the H distribution information. (authors)

Anhydrous thallium hydrogen L-glutamate: polymer networks formed by sandwich layers of oxygen-coordinated thallium ions cores shielded by hydrogen L-glutamate counterions.

Science.gov (United States)

Bodner, Thomas; Wirnsberger, Bianca; Albering, Jörg; Wiesbrock, Frank

2011-11-07

Anhydrous thallium hydrogen L-glutamate [Tl(L-GluH)] crystallizes from water (space group P2(1)) with a layer structure in which the thallium ions are penta- and hexacoordinated exclusively by the oxygen atoms of the γ-carboxylate group of the hydrogen L-glutamate anions to form a two-dimensional coordination polymer. The thallium-oxygen layer is composed of Tl(2)O(2) and TlCO(2) quadrangles and is only 3 Å high. Only one hemisphere of the thallium ions participates in coordination, indicative of the presence of the 6s(2) lone pair of electrons. The thallium-oxygen assemblies are shielded by the hydrogen l-glutamate anions. Only the carbon atom of the α-carboxylate group deviates from the plane spanned by the thallium ions, the γ-carboxylate groups and the proton bearing carbon atoms, which are in trans conformation. Given the abundance of L-glutamic and L-aspartic acid in biological systems on the one hand and the high toxicity of thallium on the other hand, it is worth mentioning that the dominant structural motifs in the crystal structure of [Tl(L-GluH)] strongly resemble their corresponding analogues in the crystalline phase of [K(L-AspH)(H(2)O)(2)].

Hydrogen formation under gamma and heavy ions irradiation of geopolymers

International Nuclear Information System (INIS)

Chupin, F.; Dannoux-Papin, A.; D'Espinose de Lacaillerie, J.B.; Ngono Ravache, Y.

2015-01-01

This study examines the behavior under irradiation of geo-polymer which is not yet well known and attempts to highlight the importance of water radiolysis. For their use as embedding matrices, stability under ionizing radiation as well as low hydrogen gas released must be demonstrated. Different formulations of geo-polymers have been irradiated either with γ-rays ( 60 Co sources) or 75 MeV 36 Ar ions beams and the production of hydrogen released has been quantified. This paper presents the results of gas analysis in order to identify important structural parameters that influence confined water radiolysis. Indeed, a correlation between pore size, water content on one side, and the hydrogen production radiolytic yield (G(H 2 )) on the other side, has been demonstrated. For the 75 MeV 36 Ar ions irradiation, the effect of porosity has not been well emphasized. For both, the results have revealed the water content influence. (authors)

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.

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

NARCIS (Netherlands)

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

2016-01-01

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

Strong charge state dependence of H+ and H2+ sputtering induced by slow highly charged ions

International Nuclear Information System (INIS)

Kakutani, N.; Azuma, T.; Yamazaki, Y.; Komaki, K.; Kuroki, K.

1995-01-01

Secondary ion emission has been studied for very slow ( similar 0.01ν B ) highly charged Ar and N ions bombarding C 60 containing hydrogen as an impurity. It is found that the fragmentations of C 60 are very rare even for Ar 16+ bombardments. On the other hand, the sputtering of H + and H 2 + has been observed to increase drastically as a function of incident charge q like q γ (e.g., γ similar 4.6 for H + sputtering by 500 eV Ar q+ ). (orig.)

Recent operation of the FNAL magnetron H- ion source

Science.gov (United States)

Karns, P. R.; Bollinger, D. S.; Sosa, A.

2017-08-01

This paper will detail changes in the operational paradigm of the Fermi National Accelerator Laboratory (FNAL) magnetron H- ion source due to upgrades in the accelerator system. Prior to November of 2012 the H- ions for High Energy Physics (HEP) experiments were extracted at ˜18 keV vertically downward into a 90 degree bending magnet and accelerated through a Cockcroft-Walton accelerating column to 750 keV. Following the upgrade in the fall of 2012 the H- ions are now directly extracted from a magnetron at 35 keV and accelerated to 750 keV by a Radio Frequency Quadrupole (RFQ). This change in extraction energy as well as the orientation of the ion source required not only a redesign of the ion source, but an updated understanding of its operation at these new values. Discussed in detail are the changes to the ion source timing, arc discharge current, hydrogen gas pressure, and cesium delivery system that were needed to maintain consistent operation at >99% uptime for HEP, with an increased ion source lifetime of over 9 months.

Hydrogen and oxygen behaviors on Porous-Si surfaces observed using a scanning ESD ion microscope

International Nuclear Information System (INIS)

Itoh, Yuki; Ueda, Kazuyuki

2004-01-01

A scanning electron-stimulated desorption (ESD) ion microscope (SESDIM) measured the 2-D images of hydrogen and oxygen distribution on solid surfaces. A primary electron beam at 600 eV, with a pulse width of 220 ns, resulted in ion yields of H + and O + . This SESDIM is applied to the surface analysis of Porous-Si (Po-Si) partially covered with SiN films. During the heating of a specimen of the Po-Si at 800 deg. C under ultra-high-vacuum (UHV) conditions, the components of the surface materials were moved or diffused by thermal decomposition accompanied by a redistribution of hydrogen and oxygen. After cyclic heating of above 800 deg. C, the dynamic behaviors of H + and O + accompanied by the movements of the SiN layers were observed as images of H + and O + . This was because the H + and O + ions have been identified as composite materials by their kinetic energies

Precipitation characteristics of uranyl ions at different pHs depending on the presence of carbonate ions and hydrogen peroxide.

Science.gov (United States)

Kim, Kwang-Wook; Kim, Yeon-Hwa; Lee, Se-yoon; Lee, Jae-Won; Joe, Kih-Soo; Lee, Eil-Hee; Kim, Jong-Seung; Song, Kyuseok; Song, Kee-Chan

2009-04-01

This work studied the dissolution of uranium dioxide and precipitation characteristics of uranyl ions in alkaline and acidic solutions depending on the presence of carbonate ions and H2O2 in the solutions at different pHs controlled by adding HNO3 or NaOH in the solution. The chemical structures of the precipitates generated in different conditions were evaluated and compared by using XRD, SEM, TG-DT, and IR analyses together. The sizes and forms of the precipitates in the solutions were evaluated, as well. The uranyl ions were precipitated in the various forms, depending on the solution pH and the presences of hydrogen peroxide and carbonate ions in the solution. In a 0.5 M Na2CO3 solution with H2O2, where the uranyl ions formed mixed uranyl peroxy-carbonato complexes, the uranyl ions were precipitated as a uranium peroxide of UO4(H20)4 at pH 3-4, and precipitated as a clarkeite of Na2U2Ox(OH)y(H2O)z above pH 13. In the same carbonate solution without H2O2, where the uranyl ions formed uranyl tris-carbonato complex, the uranyl ions were observed to be precipitated as a different form of clarkeite above pH 13. The precipitate of uranyl ions in a nitrate solution without carbonate ions and H2O2 at a high pH were studied together to compare the precipitate forms in the carbonate solutions.

A novel non-sequential hydrogen-pulsed deep reactive ion etching of silicon

International Nuclear Information System (INIS)

Gharooni, M; Mohajerzadeh, A; Sandoughsaz, A; Khanof, S; Mohajerzadeh, S; Asl-Soleimani, E

2013-01-01

A non-sequential pulsed-mode deep reactive ion etching of silicon is reported that employs continuous etching and passivation based on SF 6 and H 2 gases. The passivation layer, as an important step for deep vertical etching of silicon, is feasible by hydrogen pulses in proper time-slots. By adjusting the etching parameters such as plasma power, H 2 and SF 6 flows and hydrogen pulse timing, the process can be controlled for minimum underetch and high etch-rate at the same time. High-aspect-ratio features can be realized with low-density plasma power and by controlling the reaction chemistry. The so-called reactive ion etching lag has been minimized by operating the reactor at higher pressures. X-ray photoelectron spectroscopy and scanning electron microscopy have been used to study the formation of the passivation layer and the passivation mechanism. (paper)

Effect of helium ion bombardment on hydrogen behaviour in stainless steel

International Nuclear Information System (INIS)

Guseva, M.I.; Stolyarova, V.G.; Gorbatov, E.A.

1987-01-01

The effect of helium ion bombardment on hydrogen behaviour in 12Kh18N10T stainless steel is investigated. Helium and hydrogen ion bombardment was conducted in the ILU-3 ion accelerator; the fluence and energy made up 10 16 -5x10 17 cm -2 , 30 keV and 10 16 -5x10 18 cm -2 , 10 keV respectively. The method of recoil nuclei was used for determination of helium and hydrogen content. Successive implantation of helium and hydrogen ions into 12Kh18N10T stainless steel results in hydrogen capture by defects formed by helium ions

Guiding of slow neon and molecular hydrogen ions through nanocapillaries in PET

International Nuclear Information System (INIS)

Stolterfoht, N.; Hellhammer, R.; Sobocinski, P.; Pesic, Z.D.; Bundesmann, J.; Sulik, B.; Shah, M.B.; Dunn, K.; Pedregosa, J.; McCullough, R.W.

2005-01-01

The transmission profiles of atomic 3keV Ne 7+ ions and molecular 1keV H 2 + and H 3 + ions passing through nanocapillaries were studied. Capillaries with a diameter of 100nm and a length of 10μm in insulating PET polymers were used. The high aspect ratio of 100 is achieved by the method of etching ion tracks produced by high-energy xenon impact. The angular distributions of the transmitted projectiles show that the majority of ions are transported in their initial charge state along the capillary axis even when the capillaries are tilted with respect to the incident beam direction. This result indicates ion-guiding, which is produced by charge-up effects influencing the ion trajectories in a self-supporting manner. The guiding effects are found to be different for highly charged neon and singly charged molecular hydrogen. Negligible fragmentation of the molecular ions was observed

O--H charge exchange in cold, dense, hydrogen plasmas

International Nuclear Information System (INIS)

Cohen, S.A.; Dylla, H.F.

1977-05-01

It is pointed out that the accidentally resonant charge exchange reaction, O + + H 0 reverse arrows O 0 + H + , is an important mechanism for causing the loss of singly charged oxygen ions from oxygen contaminated hydrogen plasmas. Results of a Monte Carlo simulation are presented which show that the fraction of oxygen lost because of charge exchange exceeds 1 / 3 when the parameters n/sub e/ approx. 10 13 cm -3 , n/sub H//sup o/ approx. 10 11 cm -3 and T/sub e/ approx. 3 eV are attained

H- Enhancement Process in a Multicusp Ion Source Operated with a Barium Insert Structure

Energy Technology Data Exchange (ETDEWEB)

Leung, K.N.; Van Os, C.F.A.; Kunkel, W.B.

1990-05-01

It has been demonstrated that the H{sup -} output current from a small multicusp source can be substantially enhanced if the hydrogen plasma is seeded with barium. Operating with a barium washer insert at the extraction aperture, it is found that the extractable H{sup -} current is increased by a factor of three if the insert bias potential is optimized. By use of a mixture of xenon and hydrogen gas, it is further demonstrated that the positive hydrogen ions are responsible for the observed H{sup -} enhancement.

Chemical sputtering of graphite by H+ ions

International Nuclear Information System (INIS)

Busharov, N.P.; Gorbatov, E.A.; Gusev, V.M.; Guseva, M.I.; Martynenko, Y.V.

1976-01-01

In a study of the sputtering coefficient S for the sputtering of graphite by 10-keV H + ions as a function of the graphite temperature during the bombardment, it is found that at T> or =750degreeC the coefficient S is independent of the target temperature and has an anomalously high value, S=0.085 atom/ion. The high rate of sputtering of graphite by atomic hydrogen ions is shown to be due to chemical sputtering of the graphite, resulting primarily in the formation of CH 4 molecules. At T=1100degreeC, S falls off by a factor of about 3. A model for the chemical sputtering of graphite is proposed

Serum albumin forms a lactoferrin-like soluble iron-binding complex in presence of hydrogen carbonate ions.

Science.gov (United States)

Ueno, Hiroshi M; Urazono, Hiroshi; Kobayashi, Toshiya

2014-02-15

The iron-lactoferrin complex is a common food ingredient because of its iron-solubilizing capability in the presence of hydrogen carbonate ions. However, it is unclear whether the formation of a stable iron-binding complex is limited to lactoferrin. In this study, we investigated the effects of bovine serum albumin (BSA) on iron solubility and iron-catalyzed lipid oxidation in the presence of hydrogen carbonate ions. BSA could solubilize >100-fold molar equivalents of iron at neutral pH, exceeding the specific metal-binding property of BSA. This iron-solubilizing capability of BSA was impaired by thermally denaturing BSA at ≥ 70 °C for 10 min at pH 8.5. The resulting iron-BSA complex inhibited iron-catalyzed oxidation of soybean oil in a water-in-oil emulsion measured using the Rancimat test. Our study is the first to show that BSA, like lactoferrin, forms a soluble iron-binding complex in the presence of hydrogen carbonate ions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Generation of H-, D- ions on composite surfaces with application to surface/plasma ion source systems

International Nuclear Information System (INIS)

Hiskes, J.R.; Karo, A.M.; Wimmer, E.; Freeman, A.J.; Chubb, S.R.

1983-01-01

We review some salient features of the experimental and theoretical data pertaining to hydrogen negative ion generation on minimum-work-function composite surfaces consisting of Cs/transition metal substrates. Cesium or hydrogen ion bombardment of a cesium-activated negatively-biased electrode exposed to a cesium-hydrogen discharge results in the release of hydrogen negative ions. These ions originate through desorbtion of hydrogen particles by incident cesium ions, desorbtion by incident hydrogen ions, and by backscattering of incident hydrogen. Each process is characterized by a specific energy and angular distribution. The calculation of ion formation in the crystal selvage region is discussed for different approximations to the surface potential. An ab initio, all-electron, local density functional model for the composite surface electronics is discussed

A Facile, Nonreactive Hydrogen Peroxide (H2O2) Detection Method Enabled by Ion Chromatography with UV Detector.

Science.gov (United States)

Song, Mingrui; Wang, Junli; Chen, Baiyang; Wang, Lei

2017-11-07

Hydrogen peroxide (H 2 O 2 ) is ubiquitous in the natural environment, and it is now widely used for pollutant control in water and wastewater treatment processes. However, current analytical methods for H 2 O 2 inevitably require reactions between H 2 O 2 and other reactants to yield signals and are thus likely subjective to the interferences of coexisting colored, oxidative, and reductive compounds. In order to overcome these barriers, we herein for the first time propose to analyze H 2 O 2 by ion chromatography (IC) using an ultraviolet (UV) detector. The proposal is based on two principles: first, that H 2 O 2 can deprotonate to hydroperoxyl ion (HO 2 - ) when eluent pH is higher than the acid-dissociation coefficient of H 2 O 2 (pK a = 11.6); and second, that after separation from other compounds via IC column, H 2 O 2 can be quantified by a UV detector. Under favorable operating conditions, this method has successfully achieved acceptable recoveries (>91%) of H 2 O 2 dosed to ultrapure and natural waters, a calibration curve with R 2 > 0.99 for a wide range of H 2 O 2 concentrations from 0.1 to 50 mg/L and a method detection limit of 0.027 mg/L. In addition, this approach was shown to be capable of distinguishing H 2 O 2 from anions (e.g., fluoride and chloride) and organics (e.g., glycolate) and monochloramine, suggesting that it is insensitive to many neighboring compounds as long as they do not react quickly with H 2 O 2 . Hence, this study proves the combination of IC and UV detector a facile and reliable method for H 2 O 2 measurement.

High-current negative hydrogen ion beam production in a cesium-injected multicusp source

International Nuclear Information System (INIS)

Takeiri, Y.; Tsumori, K.; Kaneko, O.

1997-01-01

A high-current negative hydrogen ion source has been developed, where 16.2 A of the H - current was obtained with a current density of 31 mA/cm 2 . The ion source is a multicusp source with a magnetic filter for negative ion production, and cesium vapor is injected into the arc chamber, leading to enhancement of the negative ion yields. The cesium-injection effects are discussed, based on the experimental observations. Although the surface production of the negative ions on the cesium-covered plasma grid is thought to be a dominant mechanism of the H - current enhancement, the cesium effects in the plasma volume, such as the cesium ionization and the electron cooling, are observed, and could contribute to the improved operation of the negative ion source. (author)

Efficiencies of Eu{sup 3+} ions and hydrogen atoms as donors in ZnO thin films

Energy Technology Data Exchange (ETDEWEB)

Akazawa, Housei, E-mail: akazawa.housei@lab.ntt.co.jp [NTT Device Innovation Center, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)

2016-09-15

The donor efficiencies of Eu{sup 3+} ions and hydrogen atoms in ZnO crystalline films were investigated with reference to that of Ga{sup 3+} ions. It was found that Eu{sup 3+} ions acted as extrinsic donors in ZnO:Eu films, yielding a resistivity of 1.8 × 10{sup −3} Ω cm at a doping level of 1 at. %. This value is comparable to one for intrinsic donors in undoped ZnO films. The conductivity was maintained as the deposition temperature was increased to 200 °C, and this is evidence for the contribution of extrinsic donors. Deposition of Ga-doped and Eu-doped ZnO films in an H{sub 2}O gas flow produced oxyhydrogenated ZnO:(Ga, H) and ZnO:(Eu, H) films in which the Ga{sup 3+} and Eu{sup 3+} donors were deactivated by oxidization. Nevertheless, hydrogen donors contributed to electrical conduction yielding a resistivity of 1 × 10{sup −2} Ω cm. Postannealing in an H{sub 2} gas ambient alleviated the excessive oxidization of the films and thereby reactivated the donor action of Ga{sup 3+} and Eu{sup 3+} ions, causing the resistivity to recover to 10{sup −3} Ω cm for ZnO:(Ga, H) and 10{sup −2} Ω cm for ZnO:(Eu, H). In contrast, vacuum annealing of ZnO:(Ga, H) and ZnO:(Eu, H) films increased resistivity through removal of hydrogen donors while not affecting the oxidized condition of the samples.

Study of high energy ion loss during hydrogen minority heating in TFTR

International Nuclear Information System (INIS)

Park, J.; Zweben, S.J.

1994-03-01

High energy ion loss during hydrogen minority ICRF heating is measured and compared with the loss of the D-D fusion products. During H minority heating a relatively large loss of high energy ions is observed at 45 degrees below the outer midplane, with or without simultaneous NBI heating. This increase is most likely due to a loss of the minority tail protons, a possible model for this process is described

A Hydrogen Ion-Selective Sensor Based on Non-Plasticised Methacrylic-acrylic Membranes

Directory of Open Access Journals (Sweden)

Musa Ahmad

2002-08-01

Full Text Available A methacrylic-acrylic polymer was synthesised for use as a non-plasticised membrane for hydrogen ion-selective sensor incorporating tridodecylamine as an ionophore. The copolymer consisted of methyl methacrylate and n-butyl acrylate monomers in a ratio of 2:8. Characterisation of the copolymer using FTNMR demonstrated that the amount of each monomer incorporated during solution polymerisation was found to be similar to the amount used in the feed before polymerisation. The glass transition temperature of the copolymer determined by differential scanning calorimetry was -30.9 ºC. Potentiometric measurements conducted showed a linear pH response range of 4.3 – 9.6 with the response slope of 56.7 mV/decade. The selectivity of the sensors towards hydrogen ions was similar to other plasticiser based membrane electrodes and the logarithmic selectivity coefficients for discrimination against interference cations is close to –9.7. However, the incorporation of a lipophilic anion as membrane additive is essential in ensuring optimum performance of the hydrogen ion sensor.

Role of hydrogen ions in standard and activation heap leaching of gold

Science.gov (United States)

Rubtsov, YuI

2017-02-01

The role of hydrogen ions in activation heap leaching of gold from rebellious ore has been studied, which has allowed enhancing gold recovery. The author puts forward a gold leaching circuit with the use of activated oxygen-saturated solutions acidified to pH = 6-9.

Visualization of hydrogen in steels by secondary ion mass spectrometry

International Nuclear Information System (INIS)

Takai, Kenichi

2000-01-01

Secondary ion mass spectrometry (SIMS) enables us to visualize hydrogen trapping sites in steels. Information about the hydrogen trapping sites in high-strength steels by SIMS is very important to discuss environmental embrittlement mechanism for developing steels with a high resistance to the environmental embrittlement. Secondary ion image analysis by SIMS has made possible to visualize the hydrogen and deuterium trapping sites in the steels. Hydrogen in tempered martensite steels containing Ca tends to accumulate on inclusions, at grain boundaries, and in segregation bands. Visualization of hydrogen desorption process by secondary ion image analysis confirms that the bonding between the inclusions and the hydrogen is strong. Cold-drawn pearlite steels trap hydrogen along cold-drawing direction. Pearlite phase absorbs the hydrogen more than ferrite phase does. This article introduces the principle of SIMS, its feature, analysis method, and results of hydrogen visualization in steels. (author)

Precision spectroscopy of molecular hydrogen ions : Towards frequency metrology of particle masses

NARCIS (Netherlands)

Roth, B.; Koelemeij, J.; Schiller, S.; Hilico, L.; Karr, Jean Philippe; Korobov, V.I.; Bakalov, D.

2008-01-01

We describe the current status of high-precision ab initio calculations of the spectra of molecular hydrogen ions (H2+ and HD+) and of two experiments for vibrational spectroscopy. The perspectives for a comparison between theory and experiment at a level of 1 part in 109 are considered.

High brilliance multicusp ion source for hydrogen microscopy at SNAKE

Energy Technology Data Exchange (ETDEWEB)

Moser, M., E-mail: marcus.moser@unibw.de [Universitaet der Bundeswehr Muenchen, Institut fuer Angewandte Physik und Messtechnik, LRT2, Department fuer Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany); Reichart, P. [Universitaet der Bundeswehr Muenchen, Institut fuer Angewandte Physik und Messtechnik, LRT2, Department fuer Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany); Carli, W. [Maier-Leibniz-Laboraturium der LMU und TU Muenchen, 85478 Garching (Germany); Greubel, C.; Peeper, K. [Universitaet der Bundeswehr Muenchen, Institut fuer Angewandte Physik und Messtechnik, LRT2, Department fuer Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany); Hartung, P. [Maier-Leibniz-Laboraturium der LMU und TU Muenchen, 85478 Garching (Germany); Dollinger, G. [Universitaet der Bundeswehr Muenchen, Institut fuer Angewandte Physik und Messtechnik, LRT2, Department fuer Luft- und Raumfahrttechnik, 85577 Neubiberg (Germany)

2012-02-15

In order to improve the lateral resolution of the 3D hydrogen microscopy by proton-proton scattering at the Munich microprobe SNAKE, we have installed a new multicusp ion source for negative hydrogen ions manufactured by HVEE at the Munich 14 MV tandem accelerator that boosts the proton beam brilliance with the potential to reduce the beam diameter at the focal plane of SNAKE. We measured a beam brilliance B = 27 A m{sup -2} rad{sup -2} eV{sup -1} directly behind the ion source that is at the space charge limit for conventional ion sources. After preacceleration to in total 180 keV beam energy we measure a slightly reduced beam brilliance of B = 10 {mu}A mm{sup -2} mrad{sup -2} MeV{sup -1}. For injection into the tandem accelerator, the extracted H{sup -}-current of the multicusp source of 1 mA is reduced to about 10 {mu}A because of radiation safety regulations and heating problems at the object slits of SNAKE. Due to beam oscillations and influences of the terminal stripper of the tandem we measured a reduced beam brilliance of 0.8 {mu}A mm{sup -2} mrad{sup -2} MeV{sup -1} in front of SNAKE at 25 MeV but still being nearly 10 times larger than measured with any other ion source.

Hydrogen absorption kinetics of niobium with an ion-plated nickel overlayer

International Nuclear Information System (INIS)

Nakamura, K.

1981-01-01

The hydrogen absorption rate for nickel-ion-plated niobium was measured as a function of hydrogen pressure and temperature. The observed absorption curves of c(mean)/csub(e) against time (c(mean) and csub(e) are the mean and equilibrium hydrogen concentrations respectively) exhibited a marked hydrogen pressure dependence below 628 K but this was less marked above 723 K. The results were analysed on the basis of the proposed model that the rate-determining step is the hydrogen permeation through the nickel overlayer and that the permeation is driven by the hydrogen activity difference between the two interfaces, namely the H 2 -Ni and Ni-Nb interfaces. The marked pressure dependence can be attributed to the fact that the hydrogen activity coefficient in nickel is constant and that in niobium it varies markedly with concentration, i.e. with hydrogen pressure and temperature. It was also found that the change in the nickel overlayer structure caused by the dilatation of bulk niobium during hydrogen absorption enhances the hydrogen absorption rates. The temperature dependence of the hydrogen absorption rate is also discussed in comparison with that for tantalum with a vacuum-deposited nickel overlayer. (Auth.)

Ion beam analysis of oxidation and hydrogenation of switchable mirrors

International Nuclear Information System (INIS)

Huisman, M.C.; Jongerden, M.R.; Molen, S.J. van der; Vis, R.D.

2001-01-01

Thin films of Y, La or rare earth (RE) hydrides exhibit a metal insulator transition between their di- and trihydride phase. After H loading lateral diffusion samples of these materials contain an overview of all hydride phases present in the thin film phase diagram. In this paper the thin film YH x system will be investigated. The unexpected presence of a lateral oxygen profile in the YH x sample necessitates a careful interpretation of local hydrogen concentration differences. In this paper the potential of ion beam analysis will be discussed with respect to the investigation of oxidation and hydrogenation of YH x switchable mirrors. The results of the measurements will be discussed in terms of differences between bulk- and thin-film-phase diagrams of YH x . The experimental methods used are 1 H ( 4 He, 1 H) 4 He elastic recoil detection at 5 MeV and 16 O( 4 He, 4 He) 16 O resonant backscattering around 3.036 MeV

Effects of foreign gases on H- formation in a magnetic multipole hydrogen plasma source

International Nuclear Information System (INIS)

Mosbach, T

2005-01-01

The effects of admixtures of argon and xenon and of nitrogen (for the purpose of comparison between atomic and molecular additives) to a given H 2 base pressure are investigated with respect to the vibrational populations of hydrogen molecules in the electronic ground state, to the density of negative ions and to the electron energy distribution function (EEDF). This work aims to unravel the influence of the vibrational population distribution and the EEDF on the formation of negative hydrogen ions in the volume of a magnetic multipole plasma source. The admixtures of these foreign gases lead to a measurable state-specific decrease in the population of the high vibrational states of the H 2 molecule. Higher states exhibit a clearly stronger decrease with increasing foreign gas partial pressure. The measured density of the negative ions decreases with increasing noble gas partial pressure, despite the fact that the low-energy fraction of the measured EEDF is modified such that the efficiency of ion formation by dissociative attachment is more favourable. The various measurements are compared for the case of the H 2 -Ar discharge, with a global model developed for the stationary plasma state. The decrease in the density of the negative ions with increasing argon admixture can be reproduced by the model with high accuracy on the basis of measured population distributions of the vibrationally excited H 2 molecules and the measured EEDF

Hydrogen interstitial in H-ion implanted ZnO bulk single crystals: Evaluation by elastic recoil detection analysis and electron paramagnetic resonance

Energy Technology Data Exchange (ETDEWEB)

Kaida, T.; Kamioka, K.; Nishimura, T. [College of Engineering and Research Center of Ion Beam Technology, Hosei University, Koganei, Tokyo 184-8584 (Japan); Kuriyama, K., E-mail: kuri@ionbeam.hosei.ac.jp [College of Engineering and Research Center of Ion Beam Technology, Hosei University, Koganei, Tokyo 184-8584 (Japan); Kushida, K. [Department of Arts and Sciences, Osaka Kyoiku University, Kashiwara, Osaka 582-8582 (Japan); Kinomura, A. [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

2015-12-15

The origins of low resistivity in H ion-implanted ZnO bulk single crystals are evaluated by elastic recoil detection analysis (ERDA), electron paramagnetic resonance (EPR), and Van der Pauw methods. The H-ion implantation (peak concentration: 5.0 × 10{sup 15} cm{sup −2}) into ZnO is performed using a 500 keV implanter. The maximum of the concentration of the implanted H estimated by a TRIM simulation is at 3600 nm in depth. The resistivity decreases from ∼10{sup 3} Ω cm for un implanted ZnO to 6.5 Ω cm for as-implanted, 2.3 × 10{sup −1} Ω cm for 200 °C annealed, and 3.2 × 10{sup −1} Ω cm for 400 °C annealed samples. The ERDA measurements can evaluate the concentration of hydrogens which move to the vicinity of the surface (surface to 300 nm or 100 nm) because of the diffusion by the annealing at 200 °C and 400 °C. The hydrogen concentration near the surface estimated using the 2.0 MeV helium beam is ∼3.8 × 10{sup 13} cm{sup −2} for annealed samples. From EPR measurements, the oxygen vacancy of +charge state (V{sub o}{sup +}) is observed in as-implanted samples. The V{sub o}{sup +} related signal (g = 1.96) observed under no illumination disappears after successive illumination with a red LED and appears again with a blue light illumination. The activation energy of as-implanted, 200 °C annealed, and 400 °C annealed samples estimated from the temperature dependence of carrier concentration lies between 29 meV and 23 meV, suggesting the existence of H interstitial as a shallow donor level.

Space Charge Compensation in the Linac4 Low Energy Beam Transport Line with Negative Hydrogen Ions

CERN Document Server

Valerio-Lizarraga, C; Leon-Monzon, I; Lettry, J; Midttun, O; Scrivens, R

2014-01-01

The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Tranport (LEBT) using the package IBSimu1, which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H- beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

Intense negative hydrogen ion source for neutral injection into tokamaks

International Nuclear Information System (INIS)

Prelec, K.; Sluyters, T.

1975-01-01

In this scheme negative ions are extracted from a plasma source, accelerated to the required energy and then neutralized by stripping in a gas, metal vapor or plasma jet. One of the most promising direct extraction sources is the magnetron source, operating in the mixed hydrogen-cesium mode. In the present source cathode current densities are up to 20 A/cm 2 at arc voltages between 100 V and 150 V. In order to utilize the discharge more efficiently multislit extraction geometry was adopted. Highest currents were obtained by using six slits, with a total extraction area of 1.35 cm 2 . At an extraction voltage of 18 kV negative hydrogen ion currents close to 1 A were obtained, which corresponds to current densities of about 0.7 A/cm 2 at the extraction aperture. Pulse length was 10-20 ms and the repetition rate 0.1 Hz. The total extracted current was usually 2-3 times the H - current

Oxidative damage to collagen and related substrates by metal ion/hydrogen peroxide systems

DEFF Research Database (Denmark)

Hawkins, C L; Davies, Michael Jonathan

1997-01-01

. In this study electron paramagnetic resonance spectroscopy with spin trapping has been used to identify radicals formed on collagen and related materials by metal ion-H2O2 mixtures. Attack of the hydroxyl radical, from a Fe(II)-H2O2 redox couple, on collagen peptides gave signals from both side chain (.CHR...... are similar to those from the alpha-carbon site of peptides and the side-chain of lysine. Enzymatic digestion of the large, protein-derived, species releases similar low-molecular-weight adducts. The metal ion employed has a dramatic effect on the species observed. With Cu(I)-H2O2 or Cu(II)-H2O2 instead of Fe(II)-H......2O2, evidence has been obtained for: i) altered sites of attack and fragmentation, ii) C-terminal decarboxylation, and iii) hydrogen abstraction at N-terminal alpha-carbon sites. This altered behaviour is believed to be due to the binding of copper ions to some substrates and hence site...

Reflection properties of hydrogen ions at helium irradiated tungsten surfaces

International Nuclear Information System (INIS)

Doi, K; Tawada, Y; Kato, S; Sasao, M; Kenmotsu, T; Wada, M; Lee, H T; Ueda, Y; Tanaka, N; Kisaki, M; Nishiura, M; Matsumoto, Y; Yamaoka, H

2016-01-01

Nanostructured W surfaces prepared by He bombardment exhibit characteristic angular distributions of hydrogen ion reflection upon injection of 1 keV H + beam. A magnetic momentum analyzer that can move in the vacuum chamber has measured the angular dependence of the intensity and the energy of reflected ions. Broader angular distributions were observed for He-irradiated tungsten samples compared with that of the intrinsic polycrystalline W. Both intensity and energy of reflected ions decreased in the following order: the polycrystalline W, the He-bubble containing W, and the fuzz W. Classical trajectory Monte Carlo simulations based on Atomic Collision in Amorphous Target code suggests that lower atom density near the surface can make the reflection coefficients lower due to increasing number of collisions. (paper)

Understanding the mechanism of DNA deactivation in ion therapy of cancer cells: hydrogen peroxide action*

Science.gov (United States)

Piatnytskyi, Dmytro V.; Zdorevskyi, Oleksiy O.; Perepelytsya, Sergiy M.; Volkov, Sergey N.

2015-11-01

Changes in the medium of biological cells under ion beam irradiation has been considered as a possible cause of cell function disruption in the living body. The interaction of hydrogen peroxide, a long-lived molecular product of water radiolysis, with active sites of DNA macromolecule was studied, and the formation of stable DNA-peroxide complexes was considered. The phosphate groups of the macromolecule backbone were picked out among the atomic groups of DNA double helix as a probable target for interaction with hydrogen peroxide molecules. Complexes consisting of combinations including: the DNA phosphate group, H2O2 and H2O molecules, and Na+ counterion, were considered. The counterions have been taken into consideration insofar as under the natural conditions they neutralise DNA sugar-phosphate backbone. The energy of the complexes have been determined by considering the electrostatic and the Van der Waals interactions within the framework of atom-atom potential functions. As a result, the stability of various configurations of molecular complexes was estimated. It was shown that DNA phosphate groups and counterions can form stable complexes with hydrogen peroxide molecules, which are as stable as the complexes with water molecules. It has been demonstrated that the formation of stable complexes of H2O2-Na+-PO4- may be detected experimentally by observing specific vibrations in the low-frequency Raman spectra. The interaction of H2O2 molecule with phosphate group of the double helix backbone can disrupt DNA biological function and induce the deactivation of the cell genetic apparatus. Thus, the production of hydrogen peroxide molecules in the nucleus of living cells can be considered as an additional mechanism by which high-energy ion beams destroy tumour cells during ion beam therapy. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey Solov'yov, Nigel Mason, Gustavo García, Eugene

Chemical Bonding States of TiC Films before and after Hydrogen Ion Irradiation

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

TiC films deposited by rf magnetron sputtering followed by Ar+ ion bombardment were irradiated with a hydrogen ion beam. X-ray photoelectron spectroscopy (XPS) was used for characterization of the chemical bonding states of C and Ti elements of the TiC films before and after hydrogen ion irradiation, in order to understand the effect of hydrogen ion irradiation on the films and to study the mechanism of hydrogen resistance of TiC films. Conclusions can be drawn that ion bombardment at moderate energy can cause preferential physical sputtering of carbon atoms from the surface of low atomic number (Z) material. This means that ion beam bombardment leads to the formation of a non-stoichiometric composition of TiC on the surface.TiC films prepared by ion beam mixing have the more excellent characteristic of hydrogen resistance. One important cause, in addition to TiC itself, is that there are many vacant sites in TiC created by ion beam mixing.These defects can easily trap hydrogen and effectively enhance the effect of hydrogen resistance.

The RHIC polarized H{sup −} ion source

Energy Technology Data Exchange (ETDEWEB)

Zelenski, A., E-mail: zelenski@bnl.gov; Atoian, G.; Raparia, D.; Ritter, J.; Steski, D. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

2016-02-15

A novel polarization technique had been successfully implemented for the Relativistic Heavy Ion Collider (RHIC) polarized H{sup −} ion source upgrade to higher intensity and polarization. In this technique, a proton beam inside the high magnetic field solenoid is produced by ionization of the atomic hydrogen beam (from external source) in the He-gaseous ionizer cell. Further proton polarization is produced in the process of polarized electron capture from the optically pumped Rb vapor. The use of high-brightness primary beam and large cross sections of charge-exchange cross sections resulted in production of high intensity H{sup −} ion beam of 85% polarization. The source very reliably delivered polarized beam in the RHIC Run-2013 and Run-2015. High beam current, brightness, and polarization resulted in 75% polarization at 23 GeV out of Alternating Gradient Synchrotron (AGS) and 60%-65% beam polarization at 100-250 GeV colliding beams in RHIC.

Trapping and re-emission of energetic hydrogen and helium ions in materials

International Nuclear Information System (INIS)

Yamaguchi, Sadae

1981-01-01

The experimental results on the trapping and re-emission of energetic hydrogen and helium ions in materials are explained. The trapping of deuterium and helium in graphite saturates at the concentration of 10 18 ions/cm 2 . The trapping rate of hydrogen depends on the kinds of target materials. In the case of the implantation in Mo over 3 x 10 16 H/cm 2 , hydrogen is hardly trapped. On the other hand, the trapping of hydrogen in Ti, Zr and Ta which form solid solution is easily made. The hydrogen in these metals can diffuse toward the inside of metals. The deuterium retained in 316 SS decreased with time. The trapping rate reached saturation more rapidly at higher implantation temperature. The effective diffusion constant for the explanation of the re-emission process is 1/100 as small as the ordinary value. The radiation damage due to helium irradiation affects on the trapping of deuterium in Mo. The temperature dependence of the trapping rate can be explained by the diffusion model based on the Sievert's law. The re-emission of helium was measured at various temperature. At low temperature, the re-emission was low at first, then the rate increased. At high temperature, the re-emission rate was high from the beginning. (Kato, T.)

Investigations on Cs-free alternative materials for negative hydrogen ion formation

Energy Technology Data Exchange (ETDEWEB)

Kurutz, Uwe

2017-01-19

Neutral beam injection (NBI) represents a main auxiliary heating and current drive system for thermonuclear fusion devices. For ITER, a total heating power of up to 33 MW will be delivered for up to one hour pulses at particle energies of up to 1 MeV by two NBI systems. The respective ion sources will therefore have to allow for the extraction and acceleration of negative hydrogen ions at a current density of 200 A/m{sup 2} from a low pressure low temperature hydrogen plasma. Also for the succeeding demonstration reactor DEMO the application of NBI is currently discussed. Respective systems will, however, have to fulfil even higher demands, like higher powers (up to 135 MW), longer pulse lengths (2 h or even cw operation), and more restrictive constrains regarding the reliability and stability. Today efficient NBI negative hydrogen ion sources are based mainly on the conversion of positive hydrogen ions and/or hydrogen atoms at a grid surface coated with caesium. Cs is used for reducing the grid's work function which significantly enhances the particle conversion probability. However, the alkali metal is chemically very reactive and easily forms compounds with residual gas impurities. Furthermore, complex redistribution dynamics of the deposited Cs layer is given. This inherently links the application of Cs with a temporal and spatial non-stability of the negative ion yield, which contradicts the required reliability of a DEMO NBI system. Thus, for DEMO, Cs-free alternative materials for negative ion formation are investigated within this work at a flexible laboratory experiment. An ECR discharge is used which provides comparable parameters (pressure, densities, particle fluxes and -energies) to the NBI ion sources. Negative ion formation is measured above different material samples via laser photodetachment together with global plasma parameters using a Langmuir probe and optical emission spectroscopy. The plasma parameters are used for modelling the

Investigations on Cs-free alternative materials for negative hydrogen ion formation

International Nuclear Information System (INIS)

Kurutz, Uwe

2017-01-01

Neutral beam injection (NBI) represents a main auxiliary heating and current drive system for thermonuclear fusion devices. For ITER, a total heating power of up to 33 MW will be delivered for up to one hour pulses at particle energies of up to 1 MeV by two NBI systems. The respective ion sources will therefore have to allow for the extraction and acceleration of negative hydrogen ions at a current density of 200 A/m 2 from a low pressure low temperature hydrogen plasma. Also for the succeeding demonstration reactor DEMO the application of NBI is currently discussed. Respective systems will, however, have to fulfil even higher demands, like higher powers (up to 135 MW), longer pulse lengths (2 h or even cw operation), and more restrictive constrains regarding the reliability and stability. Today efficient NBI negative hydrogen ion sources are based mainly on the conversion of positive hydrogen ions and/or hydrogen atoms at a grid surface coated with caesium. Cs is used for reducing the grid's work function which significantly enhances the particle conversion probability. However, the alkali metal is chemically very reactive and easily forms compounds with residual gas impurities. Furthermore, complex redistribution dynamics of the deposited Cs layer is given. This inherently links the application of Cs with a temporal and spatial non-stability of the negative ion yield, which contradicts the required reliability of a DEMO NBI system. Thus, for DEMO, Cs-free alternative materials for negative ion formation are investigated within this work at a flexible laboratory experiment. An ECR discharge is used which provides comparable parameters (pressure, densities, particle fluxes and -energies) to the NBI ion sources. Negative ion formation is measured above different material samples via laser photodetachment together with global plasma parameters using a Langmuir probe and optical emission spectroscopy. The plasma parameters are used for modelling the inherently

Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 2. Assessing Charge Site Location and Isotope Scrambling

Science.gov (United States)

Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Donohoe, Gregory C.; Valentine, Stephen J.

2016-03-01

Ion mobility spectrometry (IMS) coupled with gas-phase hydrogen deuterium exchange (HDX)-mass spectrometry (MS) and molecular dynamic simulations (MDS) has been used for structural investigation of anions produced by electrospraying a sample containing a synthetic peptide having the sequence KKDDDDDIIKIIK. In these experiments the potential of the analytical method for locating charge sites on ions as well as for utilizing collision-induced dissociation (CID) to reveal the degree of deuterium uptake within specific amino acid residues has been assessed. For diffuse (i.e., more elongated) [M - 2H]2- ions, decreased deuterium content along with MDS data suggest that the D4 and D6 residues are charge sites, whereas for the more diffuse [M - 3H]3- ions, the data suggest that the D4, D7, and the C-terminus are deprotonated. Fragmentation of mobility-selected, diffuse [M - 2H]2- ions to determine deuterium uptake at individual amino acid residues reveals a degree of deuterium retention at incorporation sites. Although the diffuse [M - 3H]3- ions may show more HD scrambling, it is not possible to clearly distinguish HD scrambling from the expected deuterium uptake based on a hydrogen accessibility model. The capability of the IMS-HDX-MS/MS approach to provide relevant details about ion structure is discussed. Additionally, the ability to extend the approach for locating protonation sites on positively-charged ions is presented.

Small-angle scattering of ions or atoms by atomic hydrogen

International Nuclear Information System (INIS)

Franco, V.

1982-01-01

A theory for small-angle scattering of arbitrary medium- or high-energy atoms or ions by atomic hydrogen is described. Results are obtained in terms of the known closed-form and easily calculable Glauber-approximation scattering amplitudes for electron-hydrogen collisions and for collisions between the nucleus (treated as one charged particle) of the ion or atom and the hydrogen atom, and in terms of the transition form factor of the arbitrary ion or atom. Applications are made to the angular differential cross sections for the excitation of atomic hydrogen to its n = 2 states by singly charged ground-state helium ions having velocities of roughly between 1/2 and 1 a.u. The differential cross sections are obtained in terms of electron-hydrogen amplitudes and the known He + ground-state form factor. Comparisons are made with other calculations and with recent measurements. The results are in good agreement with the data. It is seen that the effect of the He + electron is to produce significant constructive interference at most energies

Atomic processes, cross sections, and reaction rates necessary for modelling hydrogen-negative-ion sources and identification of optimum H- current densities

International Nuclear Information System (INIS)

Hiskes, J.R.

1991-01-01

The principal electron excitation cross sections for vibrational excitation in a hydrogen discharge are reported. In the first chamber of a two-chamber hydrogen negative-ion-source system subject to the beam-line constraint of a maximum gas pressure, the density of vibrationally excited molecules reaches an asymptote for increasing discharge current or the equivalent fast electron density. Operating near this first-chamber asymptote, there exists a spatially-dependent maximum negative-ion density in the second chamber. With the extraction grid placed at this maximum the optimum performance of a hydrogen-based system is determined. This optimum performance provides a criterion for the selection of differing source types for fusion applications

[The effect of hydrogen peroxide on the electrochemical corrosion properties and metal ions release of nickel-chromium dental alloys].

Science.gov (United States)

Wang, Jue; Qiao, Guang-yan

2013-04-01

To investigate the effect of hydrogen peroxide on the electrochemical corrosion and metal ions release of nickel-chromium dental alloys. The corrosion resistance of nickel-chromium dental alloys was compared by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva after immersed in different concentrations of hydrogen peroxide for 112 h. The metal ions released from nickel-chromium dental alloys to the artificial saliva were detected after electrochemical measurements using inductively coupled plasma mass spectrometry (ICP-MS). The data was statistically analyzed by analysis of variance (ANOVA) using SPSS 13.0 software package. The electrochemical experiment showed that the sequence of polarization resistance in equivalent circuit (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the "pseudo-passivation" (δE) of nickel-chromium alloys in artificial saliva was 30% alloys to the artificial saliva, and the order of the concentrations of metal ions was 0% corrosion resistance of nickel-chromium dental alloys decrease after immersed in different concentrations of hydrogen peroxide for 112 h. Nickel-chromium dental alloys are more prone to corrosion in the artificial saliva with the concentration of hydrogen peroxide increased, and more metal ions are released in the artificial saliva.

Gaseous anion chemistry. Hydrogen-deuterium exchange in mono- and dialcohol alkoxide ions: ionization reactions in dialcohols

International Nuclear Information System (INIS)

Lloyd, J.R.; Agosta, W.C.; Field, F.H.

1980-01-01

The subject of this work is H-D exchange in certain gaseous anions using D 2 as the exchanging agent. The anions involved are produced from ethylene glycol, 1,3-propanediol, 1,4-butanediol, ethanol, 1-propanol, and 1-butanol. Spectra and postulated ionization reactions for these mono- and dialcohols are given. Hydrogen-deuterium exchange occurs in the (M - 1) - and (2M - 1) - ions of ethylene glycol, 1,3-propanediol, and 1,4-butanediol. The amount of exchange occurring is 3-8 times greater in (2M - 1) - than in (M - 1) - . The amount of H-D exchange occurring in ethanol, 1-propanol, and 1-butanol is small or zero in the (2M - 1) - ions and in the (M - 1) - ion for 1-butanol [the only (M - 1) - ion which could be examined experimentally]. The amount of exchange occurring in the (2M - 1) - and (M - 1) - ions from ethylene glycol is not affected by the total pressure or composition of the reaction mixture in the ionization chamber of the mass spectrometer. A novel hydrogen-bridging mechanism is suggested to account for the observed exchange occurring in the dialcohols

Mesospheric H2O and H2O2 densities inferred from in situ positive ion composition measurement

Science.gov (United States)

Kopp, E.

1984-01-01

A model for production and loss of oxonium ions in the high-latitude D-region is developed, based on the observed excess of 34(+) which has been interpreted as H2O2(+). The loss mechanism suggested in the study is the attachment of N2 and/or CO2 in three-body reactions. Furthermore, mesospheric water vapor and H2O2 densities are inferred from measurements of four high-latitude ion compositions, based on the oxonium model. Mixing ratios of hydrogen peroxide of up to two orders of magnitude higher than previous values were obtained. A number of reactions, reaction constants, and a block diagram of the oxonium ion chemistry in the D-region are given.

Historical perspective of the H- Ion Source Symposia

International Nuclear Information System (INIS)

Schmidt, C.W.

1997-11-01

The International Symposium on the Production and Neutralization of Negative Hydrogen Ions and Beams is entering its third decade of providing a forum for the H - ion source community. The first meeting was held at Brookhaven National Laboratory in 1977 and has returned there every three years to 1995. This is the eighth meeting in this series and for the first time is in Europe, hosted by CEA/Center de Cadarache. Since this Symposium is meeting in Europe many new people have had an opportunity to attend and many of these are of a younger generation. On the 20th anniversary of the First Symposium it seems fitting that a historical review should be given. The Symposium meetings and its archiving of information has been a valuable asset to this community. I hope to briefly describe the early H - source work and provide some insight into the success of the H - source effort

Historical perspective of the H- ion source symposia

International Nuclear Information System (INIS)

Schmidt, C.W.

1998-01-01

The International Symposium on the Production and Neutralization of Negative Hydrogen Ions and Beams is entering its third decade of providing a forum for the H - ion source community. The first meeting was held at Brookhaven National Laboratory in 1977 and has returned there every three years to 1995. This is the eighth meeting in this series and for the first time is in Europe, hosted by CEA/Center de Cadarache. Since this Symposium is meeting in Europe many new people have had an opportunity to attend and many of these are of a younger generation. On the 20th anniversary of the First Symposium it seems fitting that a historical review should be given. The Symposium meetings and its archiving of information has been a valuable asset to this community. I hope to briefly describe the early H - source work and provide some insight into the success of the H - source effort. copyright 1998 American Institute of Physics

Historical perspective of the H- ion source symposia

International Nuclear Information System (INIS)

Schmidt, C. W.

1998-01-01

The International Symposium on the Production and Neutralization of Negative Hydrogen Ions and Beams is entering its third decade of providing a forum for the H - ion source community. The first meeting was held at Brookhaven National Laboratory in 1977 and has returned there every three years to 1995. This is the eighth meeting in this series and for the first time is in Europe, hosted by CEA/Center de Cadarache. Since this Symposium is meeting in Europe many new people have had an opportunity to attend and many of these are of a younger generation. On the 20th anniversary of the First Symposium it seems fitting that a historical review should be given. The Symposium meetings and its archiving of information has been a valuable asset to this community. I hope to briefly describe the early H - source work and provide some insight into the success of the H - source effort

Vibrational and cascade dissociation of H{sub 2}{sup +} ions by collision with gas molecules; Dissociation vibrationnelle et dissociation en cascade d'ions H{sub 2}{sup +} par collisions avec les molecules d'un gaz

Energy Technology Data Exchange (ETDEWEB)

Verveer, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1966-07-01

Protons produced by collisional dissociation of H{sub 2}{sup +} ions have an energy spectrum with a narrow central peak. For a part the protons in this peak are produced by vibrational dissociation and for another part by a cascade of two collisions. For H{sub 2}{sup +} ions of 50 to 150 keV the cross section for vibrational dissociation is about 4.1 10{sup -19} cm{sup 2}/molecule in hydrogen and 1.1 10{sup -18} cm{sup 2}/molecule in argon. (author) [French] Les protons resultant de la dissociation par collisions d'ions H{sub 2}{sup +} dans un gaz ont un spectre d'energie qui presente un pic central tres etroit. Les protons dans ce pic proviennent, pour une part de la dissociation vibrationnelle et pour l'autre part d'une suite de deux collisions. Dans le domaine d'energie des ions H{sub 2}{sup +} de 50 a 150 keV la section efficace de dissociation vibrationnel vaut 4.1 10{sup -19} cm{sup 2}/molecule pour l'hydrogene et 1,1 10{sup -18} cm{sup 2}/molecule pour l'argon.

Electron capture by Ne3+ ions from atomic hydrogen

International Nuclear Information System (INIS)

Rejoub, R.; Bannister, M.E.; Havener, C.C.; Savin, D.W.; Verzani, C.J.; Wang, J.G.; Stancil, P.C.

2004-01-01

Using the Oak Ridge National Laboratory ion-atom merged-beam apparatus, absolute total electron-capture cross sections have been measured for collisions of Ne 3+ ions with hydrogen (deuterium) atoms at energies between 0.07 and 826 eV/u. Comparison to previous measurements shows large discrepancies between 50 and 400 eV/u. Previously published molecular-orbital close-coupling (MOCC) calculations were performed over limited energy ranges, but show good agreement with the present measurements. Here MOCC calculations are presented for energies between 0.01 and 1000 eV/u for collisions with both H and D. For energies below ∼1 eV/u, an enhancement in the magnitude of both the experimental and theoretical cross sections is observed which is attributed to the ion-induced dipole attraction between the reactants. Below ∼4 eV/u, the present calculations show a significant target isotope effect

Electron capture by Ne3+ ions from atomic hydrogen

Science.gov (United States)

Rejoub, R.; Bannister, M. E.; Havener, C. C.; Savin, D. W.; Verzani, C. J.; Wang, J. G.; Stancil, P. C.

2004-05-01

Using the Oak Ridge National Laboratory ion-atom merged-beam apparatus, absolute total electron-capture cross sections have been measured for collisions of Ne3+ ions with hydrogen (deuterium) atoms at energies between 0.07 and 826 eV/u . Comparison to previous measurements shows large discrepancies between 50 and 400 eV/u . Previously published molecular-orbital close-coupling (MOCC) calculations were performed over limited energy ranges, but show good agreement with the present measurements. Here MOCC calculations are presented for energies between 0.01 and 1000 eV/u for collisions with both H and D. For energies below ˜1 eV/u , an enhancement in the magnitude of both the experimental and theoretical cross sections is observed which is attributed to the ion-induced dipole attraction between the reactants. Below ˜4 eV/u , the present calculations show a significant target isotope effect.

Hydrogen peroxide scavenger, catalase, alleviates ion transport dysfunction in murine colitis.

Science.gov (United States)

Barrett, Kim E; McCole, Declan F

2016-11-01

Reactive oxygen species (ROS) such as hydrogen peroxide (H 2 O 2 ) contribute to epithelial damage and ion transport dysfunction (key events in inflammatory diarrhoea) in inflammatory bowel disease (IBD). The aim of this study was to identify if H 2 O 2 mediates suppression of colonic ion transport function in the murine dextran sulfate sodium (DSS) colitis model by using the H 2 O 2 degrading enzyme, catalase. Colitis was induced by administering DSS (4%) in drinking water for 5 days followed by 3 days on normal H 2 O. Mice were administered either pegylated catalase or saline at day -1, 0 and +1 of DSS treatment. Ion transport responses to the Ca 2+ -dependent agonist, carbachol (CCh), or the cAMP-dependent agonist, forskolin, were measured across distal colonic mucosa mounted in Ussing chambers. Parameters of DSS-induced inflammation (loss in body weight, decreased colon length, altered stool consistency), were only partially alleviated by catalase while histology was only minimally improved. However, catalase significantly reversed the DSS-induced reduction in baseline ion transport as well as colonic I sc responses to CCh. However, ion transport responses to forskolin were not significantly restored. Catalase also reduced activation of ERK MAP kinase in the setting of colitis, and increased expression of the Na + -K + -2Cl - cotransporter, NKCC1, consistent with restoration of ion transport function. Ex vivo treatment of inflamed colonic mucosae with catalase also partially restored ion transport function. Therefore, catalase partially prevents, and rescues, the loss of ion transport properties in DSS colitis even in the setting of unresolved tissue inflammation. These findings indicate a prominent role for ROS in ion transport dysfunction in colitis and may suggest novel strategies for the treatment of inflammatory diarrhoea. © 2016 John Wiley & Sons Australia, Ltd.

Ion beam analysis of oxidation and hydrogenation of switchable mirrors

Energy Technology Data Exchange (ETDEWEB)

Huisman, M.C. E-mail: huisman@nat.vu.nl; Jongerden, M.R.; Molen, S.J. van der; Vis, R.D

2001-07-01

Thin films of Y, La or rare earth (RE) hydrides exhibit a metal insulator transition between their di- and trihydride phase. After H loading lateral diffusion samples of these materials contain an overview of all hydride phases present in the thin film phase diagram. In this paper the thin film YH{sub x} system will be investigated. The unexpected presence of a lateral oxygen profile in the YH{sub x} sample necessitates a careful interpretation of local hydrogen concentration differences. In this paper the potential of ion beam analysis will be discussed with respect to the investigation of oxidation and hydrogenation of YH{sub x} switchable mirrors. The results of the measurements will be discussed in terms of differences between bulk- and thin-film-phase diagrams of YH{sub x}. The experimental methods used are {sup 1}H ({sup 4}He, {sup 1}H){sup 4}He elastic recoil detection at 5 MeV and {sup 16}O({sup 4}He, {sup 4}He){sup 16}O resonant backscattering around 3.036 MeV.

Simple emittance measurement of negative hydrogen ion beam using pepper-pot method

International Nuclear Information System (INIS)

Hamabe, M.; Tsumori, K.; Takeiri, Y.; Kaneko, O.; Asano, E.; Kawamoto, T.; Kuroda, T.; Guharay, S.K.

1997-01-01

A simple apparatus for emittance measurement using pepper-pot method is developed. The pepper-pot patterns are directly exposed and recorded on a Kapton foil. Using this apparatus, emittance was measured in the case of the negative hydrogen (H - ) beam from the large negative ion source, which is the 1/3 scaled test device for the negative-ion-based neutral beam injection (N-NBI) on the Large Helical Device (LHD). As the consequence of the first trial, the 95% normalized emittance value is measured as 0.59 mm mrad. (author)

Simple emittance measurement of negative hydrogen ion beam using pepper-pot method

Energy Technology Data Exchange (ETDEWEB)

Hamabe, M.; Tsumori, K.; Takeiri, Y.; Kaneko, O.; Asano, E.; Kawamoto, T.; Kuroda, T. [National Inst. for Fusion Science, Nagoya (Japan); Guharay, S.K.

1997-02-01

A simple apparatus for emittance measurement using pepper-pot method is developed. The pepper-pot patterns are directly exposed and recorded on a Kapton foil. Using this apparatus, emittance was measured in the case of the negative hydrogen (H{sup -}) beam from the large negative ion source, which is the 1/3 scaled test device for the negative-ion-based neutral beam injection (N-NBI) on the Large Helical Device (LHD). As the consequence of the first trial, the 95% normalized emittance value is measured as 0.59 mm mrad. (author)

Modeling of gas flow in the simulation of H- ion source

International Nuclear Information System (INIS)

Ogasawara, M.; Okuda, Y.; Shirai, M.; Mitsuhashi, S.; Hatayama, A.

1996-01-01

Actual gas supply into the ion source is modeled. Filling pressure is related to gas flow rate and conductance of the H - extraction system. The rate equation for the H 2 molecule with gas inflow and outflow rates related with the filling pressure are employed in the numerical simulation of a negative hydrogen ion source. With the results of numerical simulation, the H number conservation relation and pressure balance equation are shown to be inaccurate especially for higher electron temperature. Actually for 5 eV of electron temperature, lost H 2 density amounts to 79% and the pressure becomes 5 times the original pressure of 5 mTorr. Even for a low pressure of 3 mTorr, the lost fraction is 67% for 5 eV of the electron temperature. This inaccuracy is large in high power and even for low pressure operation of the ion source. copyright 1996 American Institute of Physics

THE HYDROGEN ION CONCENTRATION OF JOINT EXUDATES IN RHEUMATIC FEVER AND OTHER FORMS OF ARTHRITIS.

Science.gov (United States)

Boots, R H; Cullen, G E

1922-09-30

1. The hydrogen ion concentration of joint exudates aspirated from patients ill with acute rheumatic fever, arthritis of undetermined origin, and bacterial arthritis was determined. The hydrogen ion concentrations of the joint exudates from patients with acute rheumatic fever approximated the normal reaction of blood, varying from pH 7.27 to 7.42. Exudates from patients with arthritis of undetermined origin varied in pH from 7.33 to 7.47. The pH of a joint effusion occurring in a patient with myocardial insufficiency was 7.34. Bacteriologically, all of these fluids were sterile by ordinary means of cultivation. An exudate aspirated from a knee infected with Staphylococcus aureus had a pH of 6.69, while that from a patient having an arthritis due to Streptococcus hoemolyticus was also acid, having a pH of 6.19. 2. Since a definitely acid medium is necessary for the liberation of free salicylic acid and since all of the joint fluids from patients with acute rheumatic fever were slightly alkaline, no free salicylic acid could possibly exist in such joint fluids following the administration of salicylates.

Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

Energy Technology Data Exchange (ETDEWEB)

Valerio-Lizarraga, Cristhian A., E-mail: cristhian.alfonso.valerio.lizarraga@cern.ch [CERN, Geneva (Switzerland); Departamento de Investigación en Física, Universidad de Sonora, Hermosillo (Mexico); Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard [CERN, Geneva (Switzerland); Leon-Monzon, Ildefonso [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico); Midttun, Øystein [CERN, Geneva (Switzerland); University of Oslo, Oslo (Norway)

2014-02-15

The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup −} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

Formation of negative hydrogen ion: polarization electron capture and nonthermal shielding.

Science.gov (United States)

Ki, Dae-Han; Jung, Young-Dae

2012-09-07

The influence of the nonthermal shielding on the formation of the negative hydrogen ion (H(-)) by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section as functions of the collision energy, de Broglie wave length, Debye length, impact parameter, and spectral index of the plasma. The result shows that the nonthermal character of the plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radii. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. It is also found that the maximum position of the formation cross section approaches to the collision center with an increase of the spectral index. In addition, it is found that the formation cross section significantly decreases with an increase of the Debye length, especially, for small spectral indices.

Formation of negative hydrogen ion: Polarization electron capture and nonthermal shielding

International Nuclear Information System (INIS)

Ki, Dae-Han; Jung, Young-Dae

2012-01-01

The influence of the nonthermal shielding on the formation of the negative hydrogen ion (H − ) by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section as functions of the collision energy, de Broglie wave length, Debye length, impact parameter, and spectral index of the plasma. The result shows that the nonthermal character of the plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radii. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. It is also found that the maximum position of the formation cross section approaches to the collision center with an increase of the spectral index. In addition, it is found that the formation cross section significantly decreases with an increase of the Debye length, especially, for small spectral indices.

Synergistic methane formation on pyrolytic graphite due to combined H+ ion and H0 atom impact

International Nuclear Information System (INIS)

Haasz, A.A.; Davis, J.W.; Auciello, O.; Strangeby, P.C.; Vietzke, E.; Flaskamp, K.; Philipps, V.

1986-06-01

Exposure of graphite to multispecies hydrogenic impact, as is the case in tokamaks, could lead to synergistic mechanisms resulting in an enhancement of methane formation, and consequently in increased carbon erosion. We present results obtained in controlled experiments in our laboratories in Toronto and Juelich for the synergistic methane production due to combined sub-eV H 0 atoms and energetic H + ion impact on pyrolytic graphite. Flux densities were 10 14 -2x10 16 H 0 /cm 2 s for the sub-eV H 0 atoms and 6x10 12 -5x10 15 H + /cm 2 for H + ions of 300 eV to 2.5 keV energy. Synergistic factors (defined as the ratio of methane formation rate due to combined H 0 and H + fluxes to the sum of the formation rates due to separate species impact) ranged from about 1.5-15 for the experimental parameters used. In addition, a spectrum of formed hydrocarbons in the synergistic reaction of H + and H 0 on graphite is presented

H/CNG pathway to hydrogen

International Nuclear Information System (INIS)

Bugyra, W.J.; Martin, D.R.

2004-01-01

'Full text:' The addition of hydrogen to natural gas to produce a 'premium' fuel offers an ideal bridge to the hydrogen and fuel cell era. This pathway provides many of the expected benefits of hydrogen and fuel cells, reduces cost and risk, and facilitates the transition to hydrogen incrementally through existing infrastructure, technologies and channels. The H/CNG pathway is evaluated qualitatively and quantitatively in the context of: barriers to introducing hydrogen infrastructure and how they can be addressed; potential benefits (emissions, energy security) and drawbacks (range, technical compatibility) of H/CNG blended fuels; economics; and, comparative analysis to the use of ethanol in gasoline. Leveraging the NGV industry eases the transition to fuel cells by taking advantage of existing infrastructure, technologies, skills, codes and standards, and provides for incremental change that may be more acceptable to consumers, regulators and incumbent technology providers. The greatest benefits can be achieved through a two-track pathway. One would utilize small amounts of hydrogen in existing NGVs and installed power systems - much as ethanol is added to gasoline. The second introduce products designed specifically to operate on higher levels of H/CNG, like buses, in concentrations where the greatest emission benefits can be achieved. (author)

Microanalysis on the Hydrogen Ion Irradiated 50 wt pct TiC-C Films

Institute of Scientific and Technical Information of China (English)

Hui JIANG; Yaoguang LIU; Ningkang HUANG

2007-01-01

The 50 wt pct TiC-C films were prepared on stainless steel substrates by using a technique of ion beam mixing.These films were irradiated by hydrogen ion beam with a dose of 1×1018 ions/cm2 and an energy of 5 keV.Microanalysis of X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) were used to analyze the films before and after hydrogen ion irradiation and to study the mechanism of hydrogen resistance.

A spin-filter polarimeter for low energy hydrogen and deuterium ion beams

International Nuclear Information System (INIS)

Lemieux, S.K.; Clegg, T.B.; Karwowski, H.J.; Thompson, W.J.; Crosson, E.R.

1993-01-01

An efficient polarimeter which reveals populations of individual hyperfine states of nuclear-spin-polarized H ± (or D ± ) ion beams has been tested. This device is based on unique properties of a three-level interaction in the 2S 1/2 and 2P 1/2 states of hydrogen (or deuterium) atoms, created when the incident, polarized ion beams undergo electron pickup in cesium vapour. Used on a polarized ion source, its efficiency faciy facilitates both rapid optimization and continual monitoring of parameters that affect the beam polarization. With such sources, and perhaps in applications with polarized gas jet targets, the device has potential for an absolute accuracy of better than 2%. (orig.)

Work function dependence and isotope effect in the production of negative hydrogen ions during sputtering of adsorbed hydrogen on Cs covered Mo(100) surfaces

International Nuclear Information System (INIS)

Yu, M.L.

1977-01-01

The enhancement of the H - yield, during sputtering of adsorbed hydrogen on a Mo(100) surface, by a Cs overlayer was investigated. An exponential dependence of the H - yield on the work function was observed for a wide range of Cs coverages. A simple electron tunneling model was proposed. A large reduction in the ion yield was also observed when D 2 replaced H 2 as the adsorbate

On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

International Nuclear Information System (INIS)

Borodi, Gheorghe

2008-01-01

The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22- pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4. Reactions of CO 2 + with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H 2 densities over the full temperature range of the apparatus (10 K-300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH + , CH 2 + , and CH 4 + have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. (orig.)

On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

Energy Technology Data Exchange (ETDEWEB)

Borodi, Gheorghe

2008-12-09

The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22- pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4. Reactions of CO{sub 2}{sup +} with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H{sub 2} densities over the full temperature range of the apparatus (10 K-300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH{sup +}, CH{sub 2}{sup +}, and CH{sub 4}{sup +} have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. (orig.)

Periodic orbits of the hydrogen molecular ion and their quantization

International Nuclear Information System (INIS)

Duan, Y.; Yuan, J.; Bao, C.

1995-01-01

In a classical study of the hydrogen molecular ion beyond the Born-Oppenheimer approximation (BOA), we have found that segments of trajectories resemble that of the Born-Oppenheimer approximation periodic orbits. The importance of this fact to the classical understanding of chemical bonding leads us to a systematic study of the periodic orbits of the planar hydrogen molecular ion within the BOA. Besides introducing a classification scheme for periodic orbits, we discuss the convergence properties of families of periodic orbits and their bifurcation patterns according to their types. Semiclassical calculations of the density of states based on these periodic orbits yield results in agreement with the exact quantum eigenvalues of the hydrogen molecular ion system

Study on a negative hydrogen ion source with hot cathode arc discharge.

Science.gov (United States)

Lin, S H; Fang, X; Zhang, H J; Qian, C; Ma, B H; Wang, H; Li, X X; Zhang, X Z; Sun, L T; Zhang, Z M; Yuan, P; Zhao, H W

2014-02-01

A negative hydrogen (H(-)) ion source with hot cathode arc discharge was designed and fabricated as a primary injector for a 10 MeV PET cyclotron at IMP. 1 mA dc H(-) beam with ɛ N, RMS = 0.08 π mm mrad was extracted at 25 kV. Halbach hexapole was adopted to confine the plasma. The state of arc discharge, the parameters including filament current, arc current, gas pressure, plasma electrode bias, and the ratio of I(e(-))/I(H(-)) were experimentally studied. The discussion on the result, and opinions to improve the source were given.

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.

Fundamental atomic collisional processes in negative ion sources for H-

International Nuclear Information System (INIS)

Crandall, D.H.; Barnett, C.F.

1977-01-01

The basic collision processes which create or destroy H - in gas-phase collisions like those which occur in ion sources are discussed. Cross sections are presented which show that, for known processes, destruction is generally more likely than production. One possible production mechanism (on which there is no data) is suggested, and isotope effects between hydrogen and deuterium are discussed

Transport coefficients for carbon, hydrogen, and the organic mixture C2H3

International Nuclear Information System (INIS)

Rinker, G.

1986-02-01

Electrical and thermal transport coefficients are calculated for amorphous elemental carbon and hydrogen, using the best available systematic theoretical methods. The density range considered is 10 -3 g/cm 3 less than or equal to rho less than or equal to 10 6 g/cm 3 for carbon, and 10 -4 g/cm 3 less than or equal to rho less than or equal to 10 5 g/cm 3 for hydrogen. The temperature range considered is 10 -2 eV less than or equal to kT less than or equal to 10 4 eV. Calculational methods include relativistic partial-wave analysis of the extended Ziman theory, and nonrelativistic plane-wave analysis (Born approximation) of the original Ziman theory. Physical models include relativistic Dirac-Fock-Slater and nonrelativistic Thomas-Fermi-Dirac electron-ion potentials, and one-component-plasma ion-ion structure factors. A mixing algorithm is used to obtain approximate transport coefficients for the atomic ratio C 2 H 3 . 10 refs., 31 figs

Reduction of friction stress of ethylene glycol by attached hydrogen ions

Science.gov (United States)

Li, Jinjin; Zhang, Chenhui; Deng, Mingming; Luo, Jianbin

2014-01-01

In the present work, it is shown that the friction stress of ethylene glycol can decrease by an order of magnitude to achieve superlubricity if there are hydrogen ions attached on the friction surfaces. An ultra-low friction coefficient (μ = 0.004) of ethylene glycol between Si3N4 and SiO2 can be obtained with the effect of hydrogen ions. Experimental result indicates that the hydrogen ions adsorbed on the friction surfaces forming a hydration layer and the ethylene glycol in the contact region forming an elastohydrodynamic film are the two indispensable factors for the reduction of friction stress. The mechanism of superlubricity is attributed to the extremely low shear strength of formation of elastohydrodynamic film on the hydration layer. This finding may introduce a new approach to reduce friction coefficient of liquid by attaching hydrogen ions on friction surfaces. PMID:25428584

Fluorescent sensors based on quinoline-containing styrylcyanine: determination of ferric ions, hydrogen peroxide, and glucose, pH-sensitive properties and bioimaging.

Science.gov (United States)

Yang, Xiaodong; Zhao, Peiliang; Qu, Jinqing; Liu, Ruiyuan

2015-08-01

A novel styrylcyanine-based fluorescent probe 1 was designed and synthesized via facile methods. Ferric ions quenched the fluorescence of probe 1, whereas the addition of ferrous ions led to only small changes in the fluorescence signal. When hydrogen peroxide was introduced into the solution containing probe 1 and Fe(2+) , Fe(2+) was oxidized to Fe(3+), resulting in the quenching of the fluorescence. The probe 1/Fe(2+) solution fluorescence could also be quenched by H2 O2 released from glucose oxidation by glucose oxidase (GOD), which means that probe 1/Fe(2+) platform could be used to detect glucose. Probe 1 is fluorescent in basic and neutral media but almost non-fluorescent in strong acidic environments. Such behaviour enables it to work as a fluorescent pH sensor in both the solution and solid states and as a chemosensor for detecting volatile organic compounds with high acidity and basicity. Subsequently, the fluorescence microscopic images of probe 1 in live cells and in zebrafish were achieved successfully, suggesting that the probe has good cell membrane permeability and a potential application for imaging in living cells and living organisms. Copyright © 2014 John Wiley & Sons, Ltd.

The Hydrogen Peroxide Scavenger, Catalase, Alleviates Ion Transport Dysfunction in Murine Colitis

Science.gov (United States)

Barrett, Kim E.; McCole, Declan F.

2016-01-01

Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) contribute to epithelial damage and ion transport dysfunction (key events in inflammatory diarrhea) in inflammatory bowel disease (IBD). The aim of this study was to identify if H2O2 mediates suppression of colonic ion transport function in the murine dextran sulfate sodium (DSS) colitis model by using the H2O2 degrading enzyme, catalase. Colitis was induced by administering DSS (4%) in drinking water for 5 days followed by 3 days on normal H2O. Mice were administered either pegylated-catalase or saline at day −1, 0 and +1 of DSS treatment. Ion transport responses to the Ca2+-dependent agonist, carbachol (CCh), or the cAMP-dependent agonist, forskolin, were measured across distal colonic mucosa mounted in Ussing chambers. Parameters of DSS-induced inflammation (loss in body weight, decreased colon length, altered stool consistency), were only partially alleviated by catalase while histology was only minimally improved. However, catalase significantly reversed the DSS-induced reduction in baseline ion transport as well as colonic Isc responses to CCh. However, ion transport responses to forskolin were not significantly restored. Catalase also reduced activation of ERK MAP kinase in the setting of colitis, and increased expression of the Na+-K+-2Cl− cotransporter, NKCC1, consistent with restoration of ion transport function. Ex vivo treatment of inflamed colonic mucosae with catalase also partially restored ion transport function. Therefore, catalase partially prevents, and rescues, the loss of ion transport properties in DSS colitis even in the setting of unresolved tissue inflammation. These findings indicate a prominent role for ROS in ion transport dysfunction in colitis and may suggest novel strategies for the treatment of inflammatory diarrhea. PMID:27543846

Determination of Trace Anions in Concentrated Hydrogen Peroxide by Direct Injection Ion Chromatography with Conductivity Detection after Pt-Catalyzed On-Line Decomposition

International Nuclear Information System (INIS)

Kim, Do Hee; Lee, Bo Kyung; Lee, Dong Soo

1999-01-01

A method has been developed for the determination of trace anion impurities in concentrated hydrogen peroxide. The method involves on-line decomposition of hydrogen peroxide, ion chromatographic separation and subsequent suppressed-type conductivity detection. H 2 O 2 is decomposed in Pt-catalyst filled Gore-Tex membrane tubing and the resulting aqueous solution containing analytes is introduced to the injection valve of an ion chromatograph for periodic determinations. The oxygen gas evolving within the membrane tubing escapes freely through the membrane wall causing no problem in ion chromatographic analysis. Decomposition efficiency is above 99.99% at a flow rate of 0.4mL/min for a 30% hydrogen peroxide concentration. Analytes are quantitatively retained. The analysis results for several brands of commercial hydrogen peroxides are reported

Spectroscopic measurement of H(1S) and H2(v double-prime,J double-prime) in an H- ion source plasma

International Nuclear Information System (INIS)

Stutzin, G.C.

1990-08-01

Low pressure H 2 discharges have been used for some time as sources of H - ions. These discharges contain many different species of particles which interact with each other and with the walls of the discharge chamber. Models exist that predict the populations of the various species for given macroscopic discharge parameters. However, many of the cross sections and wall catalyzation coefficients are unknown or somewhat uncertain. Therefore, it is of interest to measure the populations of as many of these species as possible, in order to determine the validity of the models. These models predict that H - is created predominantly by the two-step process of vibrational excitation of hydrogen molecules followed by dissociative attachment of slow electrons to these vibrationally-excited hydrogen molecules. Many different collisional processes must be included in the models to explain the dependence of the various populations upon macroscopic parameters. This work presents results of spectroscopic measurements of the density and translational temperature of hydrogen atoms and of specific rotationally- and vibrationally-excited states of electronic ground-state H 2 , in a discharge optimized for H - production, as well as conventional measurements of the various charged species within the plasma. The spectroscopic measurements are performed directly by narrowband, single-photon absorption in the vacuum ultraviolet

Plasma diagnostic tools for optimizing negative hydrogen ion sources

International Nuclear Information System (INIS)

Fantz, U.; Falter, H.D.; Franzen, P.; Speth, E.; Hemsworth, R.; Boilson, D.; Krylov, A.

2006-01-01

The powerful diagnostic tool of optical emission spectroscopy is used to measure the plasma parameters in negative hydrogen ion sources based on the surface mechanism. Results for electron temperature, electron density, atomic-to-molecular hydrogen density ratio, and gas temperature are presented for two types of sources, a rf source and an arc source, which are currently under development for a neutral beam heating system of ITER. The amount of cesium in the plasma volume is obtained from cesium radiation: the Cs neutral density is five to ten orders of magnitude lower than the hydrogen density and the Cs ion density is two to three orders of magnitude lower than the electron density in front of the grid. It is shown that monitoring of cesium lines is very useful for monitoring the cesium balance in the source. From a line-ratio method negative ion densities are determined. In a well-conditioned source the negative ion density is of the same order of magnitude as the electron density and correlates with extracted current densities

Estimation of Sputtering Damages on a Magnetron H- Ion Source Induced by Cs+ and H+ Ions

CERN Document Server

Pereira, H; Alessi, J; Kalvas, t

2013-01-01

An H− ion source is being developed for CERN’s Linac4 accelerator. A beam current requirement of 80 mA and a reliability above 99% during 1 year with 3 month uninterrupted operation periods are mandatory. To design a low-maintenance long life-time source, it is important to investigate and understand the wear mechanisms. A cesiated plasma discharge ion source, such as the BNL magnetron source, is a good candidate for the Linac4 ion source. However, in the magnetron source operated at BNL, the removal of material from the molybdenum cathode and the stainless steel anode cover plate surfaces is visible after extended operation periods. The observed sputtering traces are shown to result from cesium vapors and hydrogen gas ionized in the extraction region and subsequently accelerated by the extraction field. This paper presents a quantitative estimate of the ionization of cesium and hydrogen by the electron and H− beams in the extraction region of BNL’s magnetron ion source. The respective contributions o...

Hydrogen atom temperature measured with wavelength-modulated laser absorption spectroscopy in large scale filament arc negative hydrogen ion source

International Nuclear Information System (INIS)

Nakano, H.; Goto, M.; Tsumori, K.; Kisaki, M.; Ikeda, K.; Nagaoka, K.; Osakabe, M.; Takeiri, Y.; Kaneko, O.; Nishiyama, S.; Sasaki, K.

2015-01-01

The velocity distribution function of hydrogen atoms is one of the useful parameters to understand particle dynamics from negative hydrogen production to extraction in a negative hydrogen ion source. Hydrogen atom temperature is one of the indicators of the velocity distribution function. To find a feasibility of hydrogen atom temperature measurement in large scale filament arc negative hydrogen ion source for fusion, a model calculation of wavelength-modulated laser absorption spectroscopy of the hydrogen Balmer alpha line was performed. By utilizing a wide range tunable diode laser, we successfully obtained the hydrogen atom temperature of ∼3000 K in the vicinity of the plasma grid electrode. The hydrogen atom temperature increases as well as the arc power, and becomes constant after decreasing with the filling of hydrogen gas pressure

Negative ion emission at field electron emission from amorphous (alpha-C:H) carbon

CERN Document Server

Bernatskij, D P; Ivanov-Omskij, V I; Pavlov, V G; Zvonareva, T K

2001-01-01

The study on the electrons field emission from the plane cathode surface on the basis of the amorphous carbon film (alpha-C:H) is carried out. The methodology, making it possible to accomplish simultaneously the registration of the emission currents and visually observe the distribution of the emission centers on the plane emitter surface is developed. The analysis of the oscillograms indicated that apart from the proper electron constituent the negative ions of hydrogen (H sup - and H sub 2 sup -), carbon (C sup -) and hydrocarbon (CH sub n sup -) are observed. The ions emission is connected with the processes of formation and degradation of the local emission centers

Influence of the pH on molecular hydrogen primary yields in He{sup 2+} ion tracks in liquid water. A Monte Carlo study

Energy Technology Data Exchange (ETDEWEB)

Cobut, Vincent [Departement de Chimie, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville/Oise, 95031 Cergy-Pontoise Cedex (France)]. E-mail: vincent.cobut@chim.u-cergy.fr; Corbel, Catherine [CEA-Saclay, DSM/DRECAM/SCM/Laboratoire de Radiolyse, Bat. 546, Piece 5, 91191 Gif-sur-Yvette Cedex (France); Patau, Jean Paul [Faculte de Pharmacie, Universite Paul-Sabatier, 35 chemin des Maraichers, 31062 Toulouse Cedex 4 (France)

2005-02-01

Monte Carlo calculations are performed to investigate how the acidity of aqueous solutions at room temperature affects the molecular hydrogen (H{sub 2}) yield as a function of time in 20 MeV-He{sup 2+} ion track segments. For pH values varying from 1 to 13, the time dependence of the calculated yields is nearly independent of pH in the time range 10{sup -12}-10{sup -8} s and only weakly dependent in the time range 10{sup -8}-10{sup -6} s. To understand this behaviour, the kinetic mechanisms governing H{sub 2} formation are examined as a function of time. It is found that the main reactions responsible for the H{sub 2} yield as a function of time are strongly pH-dependent at low and high pH values. The pH-dependences of the reaction yields are however such that the variations in the yields compensate each other. This is why the time dependence of the H{sub 2} yield is only weakly pH-dependent.

Hydrogen retention properties of lithium film

International Nuclear Information System (INIS)

Kanaya, Koh; Yamauchi, Yuji; Hirohata, Yuko; Hino, Tomoaki; Mori, Kintaro

1998-01-01

Hydrogen retention properties of Li films and lithium oxide-lithium hydroxide (Li 2 O-LiOH) mixed films were investigated by two methods, hydrogen ion irradiation and hydrogen glow discharge. In a case of the hydrogen ion irradiation, thermal desorption spectrum of hydrogen retained in Li 2 O-LiOH film had two desorption peaks at around 470 K and 570 K. The ratio between retained hydrogen and Li atom was about 0.7. In a case of the hydrogen glow discharge, the hydrogen was also gettered in Li film during the discharge. The ratio of H/Li was almost 0.9. Most of gettered hydrogen desorbed by a baking with a temperature of 370 K. On the contrary, when the Li film exposed to the atmosphere was irradiated by the hydrogen plasma, the desorption of H 2 O was observed in addition to the adsorption of H 2 . (author)

Control of entanglement following the photoionization of trapped, hydrogen-like ions

International Nuclear Information System (INIS)

Radtke, Thomas; Fritzsche, Stephan; Surzhykov, Andrey

2005-01-01

Density matrix theory is applied to re-investigate the entanglement in the spin state of pairs of electrons following the photoionization of trapped, hydrogen-like ions. For the ionization of one out of two non-interacting atoms, in particular, we analyzed how the entanglement between the electrons is changed owing to their interaction with the radiation field. Detailed calculations on the concurrence of the final spin-state of the electrons have been performed for the photoionization of hydrogen as well as for hydrogen-like Xe 53+ and U 91+ ions. From these computations it is shown that the degree of entanglement, which is quite well preserved for neutral hydrogen, will be strongly affected by relativistic and non-dipole effects of the radiation field as the nuclear charge of the ions is increased

Procedure for reducing hydrogen ion concentration in acidic anion eluate

International Nuclear Information System (INIS)

Parobek, P.; Baloun, S.; Plevac, S.

1992-01-01

A procedure is suggested for reducing the concentration of hydrogen ions in the acidic anionic eluate formed during the separation of uranium. The procedure involves anex elution, precipitation, filtration, precipitate rinsing, and anex rinsing. The procedure is included in the uranium elution process and requires at least one ion exchanger column and at least one tank in the continuous or discontinuous mode. Sparing the neutralizing agent by reducing the hydrogen ion concentration in the acidic anionic eluate is a major asset of this procedure. (Z.S.). 1 fig

Hydrogenation effects on the lithium ion battery performance of TiOF2

Science.gov (United States)

He, Min; Wang, Zhihui; Yan, Xiaodong; Tian, Lihong; Liu, Gao; Chen, Xiaobo

2016-02-01

Hydrogenated titanium oxyfluorides (TiOF2) nanoparticles were synthesized via one-pot hydrothermal method and subsequent hydrogenation treatment. As anode materials for lithium ion batteries, the hydrogenated TiOF2 showed a superior rate performance compared to the pristine TiOF2. A charge capacity of 118.4 mA h g-1 was achieved at the current density of 1053 mA g-1 upon 150 cycles, which was 4 times higher than that of the pristine TiOF2. The rate performance of the hydrogenated TiOF2 at different current densities of 42, 210, 1053, 2106, 5265, 10530, 21060 and 52650 mA g-1 was 2.8, 6.0, 13.2, 14.7, 21.5, 30.6, 67.9 and 483.3 times higher than those of the pristine TiOF2 electrode at the corresponding rates, respectively. The remarkable improvement of the electrochemical performance was likely related to the size breakdown in the (001) direction after hydrogenation, instead of oxygen vacancies induced better charge transfer properties.

Investigation of hydrogen micro-kinetics in metals with ion beam implantation and analysis

International Nuclear Information System (INIS)

Wang, T.S.; Peng, H.B.; Lv, H.Y.; Han, Y.C.; Grambole, D.; Herrmann, F.

2007-01-01

One of the most important subjects in the fusion material research is to study the hydrogen and helium concentration, diffusion and evolution in the structure material of fusion reactor, since the hydrogen and helium can be continuously produced by the large dose fast neutron irradiation on material. Various analysis Methods can be used, but the ion beam analysis method has some advantages for studying the hydrogen behaviors in nano- or micrometer resolution. In this work, the hydrogen motion and three-dimensional distribution after implantation into metal has been studied by resonance NRA, micro-ERDA and XRD etc Methods. The resolution of the H-depth-profile is in nanometer level and the lateral resolution can be reached to 2 micrometers. The evolution of hydrogen depth-profile in a titanium sample has been studied versus the change of normal stress in samples. Evident hydrogen diffusion has been observed, while a normal stress is changed in the range of 107-963 MPa. A new phase transformation during the hydrogenation is observed by the in-situ XRD analysis. The further study on the hydrogen behaviors in the structure materials of fusion reactor is in plan. (authors)

Accurate stopping power determination of 15N ions for hydrogen depth profiling by a combination of ion beams and synchrotron radiation

Science.gov (United States)

Zier, M.; Reinholz, U.; Riesemeier, H.; Radtke, M.; Munnik, F.

2012-02-01

Hydrogen analysis is of particular importance in thin film technology and it is often necessary to obtain a depth profile. The method with the best depth resolution is NRA using the 6385 keV resonance of the 1H( 15N,αγ) 12C nuclear reaction. The correct quantification of the depth and concentration scales in the measured hydrogen profiles relies on accurate stopping power values. We present a method to deduce these values from a combination of two techniques: NRA and X-ray reflectometry (XRR). This method is applied to the determination of the stopping power of ˜6.4 MeV 15N ions in H-containing amorphous Si-layers (a-Si:H). Density-independent stopping powers at different H concentrations are determined by combining the results from NRA and XRR with an overall uncertainty of 3.3%, showing good agreement with SRIM values. This work shows exemplary the methodology for future evaluation of stopping powers for quality assurance in NRA.

Multiply charged negative ions of hydrogen in linearly polarized laser fields

International Nuclear Information System (INIS)

van Duijn, E.; Muller, H.G.

1997-01-01

Motivated by the prediction of the appearance of atomic multiply charged negative ions (AMCNI) of hydrogen, induced by a linearly polarized laser field, we present an analytical quantum mechanical treatment of the appearance and structure of AMCNI in a linearly polarized field, based on high-frequency Floquet theory (HFFT). For the simplest AMCNI of hydrogen, H 2- and H 3- , the values of α 0 at which the first bound state appears are α 0 =1.62x10 2 and α 0 =1.02x10 4 , where α 0 =I 1/2 /ω 2 is the amplitude of the oscillation of a free electron in the field with frequency ω and intensity I (unless stated otherwise, we use atomic units throughout this paper). Whereas in vacuum at least one of the electrons of an AMCNI autodetaches, an intense high-frequency field can change the character of the ion dramatically, such that bound states of AMCNI can appear. Due to the interaction with the field, the electrons of the AMCNI oscillate in phase along the polarization axis. This open-quotes quiverclose quotes motion enables the electrons to be spatially separated over distances of order α 0 , reducing the repulsive e-e interaction as α 0 increases. In other words, for α 0 large enough, the field enables a configuration in which the electrons, while widely separated, are bound to one proton. For the prediction of bound states of H N- with N>3, however, a relativistic description or low-frequency theory is required. copyright 1997 The American Physical Society

XUV-Exposed, Non-Hydrostatic Hydrogen-Rich Upper Atmospheres of Terrestrial Planets. Part II: Hydrogen Coronae and Ion Escape

Science.gov (United States)

Lammer, Helmut; Holmström, Mats; Panchenko, Mykhaylo; Odert, Petra; Erkaev, Nikolai V.; Leitzinger, Martin; Khodachenko, Maxim L.; Kulikov, Yuri N.; Güdel, Manuel; Hanslmeier, Arnold

2013-01-01

Abstract We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a “super-Earth” with a radius of 2 REarth and a mass of 10 MEarth, located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×1025 s−1 to ∼5.3×1030 s−1, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EOH) to stars—Early atmospheres—Earth-like exoplanets—Energetic neutral atoms—Ion escape—Habitability. Astrobiology 13, 1030–1048. PMID:24283926

X-ray spectroscopy of hydrogen-like ions in an electron beam ion trap

Energy Technology Data Exchange (ETDEWEB)

Tarbutt, M.R.; Crosby, D.; Silver, J.D. [Univ. of Oxford, Clarendon Lab. (United Kingdom); Myers, E.G. [Dept. of Physics, Florida State Univ., Tallahassee, FL (United States); Nakamura, N.; Ohtani, S. [ICORP, JST, Chofu, Tokyo (Japan)

2001-07-01

The X-ray emission from highly charged hydrogen-like ions in an electron beam ion trap is free from the problems of satellite contamination and Doppler shifts inherent in fast-beam sources. This is a favourable situation for the measurement of ground-state Lamb shifts in these ions. We present recent progress toward this goal, and discuss a method whereby wavelength comparison between transitions in hydrogenlike ions of different nuclear charge Z, enable the measurement of QED effects without requiring an absolute calibration.

CW/Pulsed H- ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

Science.gov (United States)

Peng, S. X.; Ren, H. T.; Xu, Y.; Zhang, T.; Zhang, A. L.; Zhang, J. F.; Zhao, J.; Guo, Z. Y.; Chen, J. E.

2015-04-01

Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H- beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H- source able to produce very intense H- beams with important variation of the duty factor[1]. Recently, a new version of 2.45 GHz microwave H- ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H- ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H- beam with rms emittance about 0.16 π.mm.mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H- ion beam at 35 keV with rms emittance about 0.2 π.mm.mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H- source body is ϕ116 mm × 124 mm, and the entire H- source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper.

Effects of Hydrogen Ion Implantation on TiC-C Coating of Stainless Steel

Institute of Scientific and Technical Information of China (English)

ZHANG Rui-qian; LIU Yao-guang; HUANG Ning-kang

2008-01-01

Titanium carbide coatings are widely used as various wear-resistant material.The hydrogen erosion resistance of TiC-C films and the effect of hydrogen participation on TiC-C films were studied.Seventy-five percent TiC-C films are prepared on stainless steel surface by using ion mixing,where TiC-C films are deposited by rf magnetron sputtering followed by argon ion bombardment.The samples are then submitted to hydrogen ion implantation at 1.2×10-3 Pa.Characterization for the 75% TiC-C films was done with SIMS,XRD,AES,and XPS.Secondary ion mass spectroscopy (SIMS) was used to analyze hydrogen concentration variation with depth,X-Ray diffraction (XRD) was used to identify the phases,and Auger electron spectra (AES) as well as X-ray photoelectron spectra (XPS) were used to check the effects of hydrogen on shifts of chemical bonding states of C and Ti in the TiC-C films.It is found that TiC-C films on stainless steel surface can prevent hydrogen from entering stainless steel.

Efficient preparation of highly hydrogenated graphene and its application as a high-performance anode material for lithium ion batteries

Science.gov (United States)

Chen, Wufeng; Zhu, Zhiye; Li, Sirong; Chen, Chunhua; Yan, Lifeng

2012-03-01

A novel method has been developed to prepare hydrogenated graphene (HG) via a direct synchronized reduction and hydrogenation of graphene oxide (GO) in an aqueous suspension under 60Co gamma ray irradiation at room temperature. GO can be reduced by the aqueous electrons (eaq-) while the hydrogenation takes place due to the hydrogen radicals formed in situ under irradiation. The maximum hydrogen content of the as-prepared highly hydrogenated graphene (HHG) is found to be 5.27 wt% with H/C = 0.76. The yield of the target product is on the gram scale. The as-prepared HHG also shows high performance as an anode material for lithium ion batteries.

Numerical analysis of electronegative plasma in the extraction region of negative hydrogen ion sources

International Nuclear Information System (INIS)

Kuppel, S.; Matsushita, D.; Hatayama, A.; Bacal, M.

2011-01-01

This numerical study focuses on the physical mechanisms involved in the extraction of volume-produced H - ions from a steady state laboratory negative hydrogen ion source with one opening in the plasma electrode (PE) on which a dc-bias voltage is applied. A weak magnetic field is applied in the source plasma transversely to the extracted beam. The goal is to highlight the combined effects of the weak magnetic field and the PE bias voltage (upon the extraction process of H - ions and electrons). To do so, we focus on the behavior of electrons and volume-produced negative ions within a two-dimensional model using the particle-in-cell method. No collision processes are taken into account, except for electron diffusion across the magnetic field using a simple random-walk model at each time step of the simulation. The results show first that applying the magnetic field (without PE bias) enhances H - ion extraction, while it drastically decreases the extracted electron current. Secondly, the extracted H - ion current has a maximum when the PE bias is equal to the plasma potential, while the extracted electron current is significantly reduced by applying the PE bias. The underlying mechanism leading to the above results is the gradual opening by the PE bias of the equipotential lines towards the parts of the extraction region facing the PE. The shape of these lines is due originally to the electron trapping by the magnetic field.

Numerical analysis of electronegative plasma in the extraction region of negative hydrogen ion sources

Science.gov (United States)

Kuppel, S.; Matsushita, D.; Hatayama, A.; Bacal, M.

2011-01-01

This numerical study focuses on the physical mechanisms involved in the extraction of volume-produced H- ions from a steady state laboratory negative hydrogen ion source with one opening in the plasma electrode (PE) on which a dc-bias voltage is applied. A weak magnetic field is applied in the source plasma transversely to the extracted beam. The goal is to highlight the combined effects of the weak magnetic field and the PE bias voltage (upon the extraction process of H- ions and electrons). To do so, we focus on the behavior of electrons and volume-produced negative ions within a two-dimensional model using the particle-in-cell method. No collision processes are taken into account, except for electron diffusion across the magnetic field using a simple random-walk model at each time step of the simulation. The results show first that applying the magnetic field (without PE bias) enhances H- ion extraction, while it drastically decreases the extracted electron current. Secondly, the extracted H- ion current has a maximum when the PE bias is equal to the plasma potential, while the extracted electron current is significantly reduced by applying the PE bias. The underlying mechanism leading to the above results is the gradual opening by the PE bias of the equipotential lines towards the parts of the extraction region facing the PE. The shape of these lines is due originally to the electron trapping by the magnetic field.

Hydrogen ion input to the Hubbard Brook Experimental Forest, New Hampshire, during the last decade

Science.gov (United States)

Gene E. Likens; F. Herbert Bormann; John S. Eaton; Robert S. Pierce; Noye M. Johnson

1976-01-01

Being downwind of eastern and midwestern industrial centers, the Hubbard Brook Experimental Forest offers a prime location to monitor long-term trends in atmospheric chemistry. Continuous measurements of precipitation chemistry during the last 10 years provide a measure of recent changes in precipitation inputs of hydrogen ion. The weighted average pH of precipitation...

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.

Population of the 3s state in hydrogen due to H+, H2+ and H3+ impact on ethylene, 1-butene and cis-2-butene

International Nuclear Information System (INIS)

Loyd, D.H.; Dawson, H.R.

1983-01-01

Absolute cross sections were measured for capture or dissociation into the 3s state of atomic hydrogen due to impact of 14-28 keV H + , H +2 and H +3 ions on ethylene, 1-butene and cis-2-butene. The cross sections obtained for the butene targets were almost identical and support the additive rule for cross sections. Ethylene cross sections were 21% lower than the values predicted by the additive rule, which agrees well with the observed trend toward reduction in total electron capture cross sections for protons on these gases at much higher energies

Recombination of H3+ and D3+ ions with electrons in low temperature plasma

International Nuclear Information System (INIS)

Glosik, J; Plasil, R.; Pysanenko, A.; Poterya, V.; Kudrna, P.; Zakouril, P.

2002-01-01

From the decaying plasma (stationary afterglow) in the mixture of He, Ar and H 2 (or D 2 ) we determined the overall recombination rate constant (α eff ) of the recombination of H 3 + and D 3 + ions with electrons at thermal energies. We observed dependence of recombination rate coefficients on partial pressure of hydrogen (and deuterium), which indicates that observed recombination is the three-body process proceeding most probably via formation of long lived intermediate state. From the obtained data we conclude that binary dissociative recombination of H 3 + and D 3 + ions with electrons is very slow with rate coefficient α DR -9 cm 3 s -1 and α DR -9 cm 3 s -1 , respectively. (author)

Simulation of RF power and multi-cusp magnetic field requirement for H{sup −} ion sources

Energy Technology Data Exchange (ETDEWEB)

Pathak, Manish [Ion Source Lab., Proton Linac & Superconducting Cavities Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Senecha, V.K., E-mail: kumarvsen@gmail.com [Ion Source Lab., Proton Linac & Superconducting Cavities Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Homi Bhabha National Institute, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Kumar, Rajnish; Ghodke, Dharmraj V. [Ion Source Lab., Proton Linac & Superconducting Cavities Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India)

2016-12-01

A computer simulation study for multi-cusp RF based H{sup −} ion source has been carried out using energy and particle balance equation for inductively coupled uniformly dense plasma considering sheath formation near the boundary wall of the plasma chamber for RF ion source used as high current injector for 1 Gev H{sup −} Linac project for SNS applications. The average reaction rates for different reactions responsible for H{sup −} ion production and destruction have been considered in the simulation model. The RF power requirement for the caesium free H{sup -} ion source for a maximum possible H{sup −} ion beam current has been derived by evaluating the required current and RF voltage fed to the coil antenna using transformer model for Inductively Coupled Plasma (ICP). Different parameters of RF based H{sup −} ion source like excited hydrogen molecular density, H{sup −} ion density, RF voltage and current of RF antenna have been calculated through simulations in the presence and absence of multicusp magnetic field to distinctly observe the effect of multicusp field. The RF power evaluated for different H{sup −} ion current values have been compared with the experimental reported results showing reasonably good agreement considering the fact that some RF power will be reflected from the plasma medium. The results obtained have helped in understanding the optimum field strength and field free regions suitable for volume emission based H{sup −} ion sources. The compact RF ion source exhibits nearly 6 times better efficiency compare to large diameter ion source.

Metal and hydrogen catalysis in isotopic hydrogen exchange in some biologically important heterocyclic compounds

International Nuclear Information System (INIS)

Buncel, E.; Joly, H.A.; Jones, J.R.; Onyido, I.

1989-01-01

This study reports on the catalytic roles of metal and hydrogen ions in tritium exchange in some heterocyclic substrates which occur as residues in many biologically important molecules. We have found that detritiation of 1-methyl[2- 3 H]imidazole is inhibited by a number of metal ions. As well, inhibition of exchange rates was noted with Ag(I) and Cu(II) for [2- 3 H]thiazole and 1-methyl[8- 3 H]inosine, with Ag(I) for [2- 3 H]benzothiazole, and with Cu(II) for 1-methyl[8- 3 H]guanosine. A complete mechanistic description, which includes the various metal ion-coordinated species generated under the experimental conditions, is presented. The results demonstrate the reactivity order: protonated >> metal-coordinated >> neutral substrates. The differential catalytic effects of metal and hydrogen ions in these processes are discussed in terms of the extent of charge developed on the ligating heteroatom in the reaction intermediate. (author). 13 refs.; 1 fig

Simulations of negative hydrogen ion sources

Science.gov (United States)

Demerdjiev, A.; Goutev, N.; Tonev, D.

2018-05-01

The development and the optimisation of negative hydrogen/deuterium ion sources goes hand in hand with modelling. In this paper a brief introduction on the physics and types of different sources, and on the Kinetic and Fluid theories for plasma description is made. Examples of some recent models are considered whereas the main emphasis is on the model behind the concept and design of a matrix source of negative hydrogen ions. At the Institute for Nuclear Research and Nuclear Energy of the Bulgarian Academy of Sciences a new cyclotron center is under construction which opens new opportunities for research. One of them is the development of plasma sources for additional proton beam acceleration. We have applied the modelling technique implemented in the aforementioned model of the matrix source to a microwave plasma source exemplifying a plasma filled array of cavities made of a dielectric material with high permittivity. Preliminary results for the distribution of the plasma parameters and the φ component of the electric field in the plasma are obtained.

Studies of an inductively coupled negative hydrogen ion radio frequency source through simulations and experiments

International Nuclear Information System (INIS)

Bandyopadhyay, M.

2004-01-01

In the frame work of a development project for ITER neutral beam injection system a radio frequency (RF) driven negative hydrogen (H-/D-) ion source, (BATMAN ion source) is developed which is designed to produce several 10s of ampere of H-/D- beam current. This PhD work has been carried out to understand and optimize BATMAN ion source. The study has been done with the help of computer simulations, modeling and experiments. The complete three dimensional Monte-Carlo computer simulation codes have been developed under the scope of this PhD work. A comprehensive description about the volume production and the surface production of H- ions is presented in the thesis along with the study results obtained from the simulations, modeling and the experiments. One of the simulations is based on the volume production of H- ions, where it calculates the density profile of the vibrationally excited H2 molecules, the density profile of H- ions and the transport probability of those H- ions along the source axis towards the grid. The other simulation studies the transport of those H- ions which are produced on the surface of the plasma grid. It is expected that if there is a plasma flow in the source, the transport of plasma components (molecules and ions) would be influenced. Experimentally it is observed that there is a convective plasma flow exists in the ion source. A transverse magnetic filter field which is present near the grid inside the ion source reduces the flow velocity. Negative ions and electrons have the same sign of charge; therefore the electrons are co-extracted with the negative ions through the grid system, which is not desirable. It is observed that a magnetic field near the grid, magnetized the electrons and therefore reduce the co-extracted electron current. It is also observed experimentally that if the plasma grid is biased positively with respect to the source body, the electron density near the plasma grid is reduced and therefore the co

The formation of [M-H]+ ions in N-alkyl-substituted thieno[3,4-c]-pyrrole-4,6-dione derivatives during atmospheric pressure photoionization mass spectrometry

KAUST Repository

Sioud, Salim

2014-10-09

RESULTS [M-H]+ ions were observed under APPI conditions. The type of dopant and the length of the alkyl chain affected the formation of these ions. MS/MS fragmentation of [M-H]+ and [M + H]+ ions exhibited completely different patterns. Theoretical calculations revealed that the loss of hydrogen molecules from the [M + H]+ ions is the most favourable condition under which to form [M-H]+ ions.CONCLUSIONS [M-H]+ ions were detected in all the TPD derivatives studied here under the special experimental conditions during APPI, using a halogenated benzene dopant, and TPD containing substituted N-alkyl side chains with a minimum of four carbon atoms. Density functional theory calculations showed that for [M-H]+ ions to be formed under these conditions, the loss of hydrogen molecules from the [M + H]+ ions is proposed to be necessary.RATIONALE The formation of ions during atmospheric pressure photoionization (APPI) mass spectrometry in the positive mode usually provides radical cations and/or protonated species. Intriguingly, during the analysis of some N-alkyl-substituted thieno[3,4-c]pyrrole-4,6-dione (TPD) derivatives synthesized in our laboratory, unusual [M-H]+ ion peaks were observed. In this work we investigate the formation of [M-H]+ ions observed under APPI conditions.METHODS Multiple experimental parameters, including the type of ionization source, the composition of the solvent, the type of dopant, the infusion flow rate, and the length of the alkyl side chain were investigated to determine their effects on the formation of [M-H]+ ions. In addition, a comparison study of the gas-phase tandem mass spectrometric (MS/MS) fragmentation of [M + H]+ vs [M-H]+ ions and computational approaches were used.

H passivation of Li on Zn-site in ZnO: Positron annihilation spectroscopy and secondary ion mass spectrometry

Science.gov (United States)

Johansen, K. M.; Zubiaga, A.; Tuomisto, F.; Monakhov, E. V.; Kuznetsov, A. Yu.; Svensson, B. G.

2011-09-01

The interaction of hydrogen (H) with lithium (Li) and zinc vacancies (VZn) in hydrothermally grown n-type zinc oxide (ZnO) has been investigated by positron annihilation spectroscopy (PAS) and secondary ion mass spectrometry. Li on Zn-site (LiZn) is found to be the dominant trap for migrating H atoms, while the trapping efficiency of VZn is considerably smaller. After hydrogenation, where the LiZn acceptor is passivated via formation of neutral LiZn-H pairs, VZn occurs as the prime PAS signature and with a concentration similar to that observed in nonhydrogenated Li-poor samples. Despite a low efficiency as an H trap, the apparent concentration of VZn in Li-poor samples decreases after hydrogenation, as detected by PAS, and evidence for formation of the neutral VZnH2 complex is presented.

Multiphoton ionization for hydrogen plasma diagnostics

International Nuclear Information System (INIS)

Bonnie, J.H.M.

1987-01-01

In this thesis the processes leading to the formation of negative ions (H - ) in hydrogen discharges are studied. These ions enable efficient production of a beam of fast neutral particles. Such beams are applied in nuclear fusion research. A model has been generally accepted in which H - is formed by means of dissociative attachment (DA) of electrons to vibrationally excited hydrogen molecules [H 2 (υ'')] molecule: when υ'' is low, electron emission is most probable, but when υ'' is high, H - production dominates. A necessary preliminary to the DA process is the presence of sufficient [H 2 (υ'')] molecules with υ'' > 4. By determining the densities of hydrogen molecules in the various vibrational levels as a function of the various discharge parameters (scaling laws), insight can be gained into the extent to which the DA process contributes to H - formation. Since the de-excitation of [H 2 (υ'')] molecules by H atoms is expected to have a large cross section, it is also relevant to determine the scaling laws for atomic hydrogen. This thesis gives an account of the development of an experimental setup for obtaining such measurements, and reports the first results achieved. In view of the anticipated density of the vibrationally excited molecules and the detection limit considered feasible, the diagnostic chosen was resonance-enhanced multiphoton ionization (REMPI). The principle is based on state-selective ionization with REMPI of particles effusing from the discharge chamber through an aperture in the wall. The ions produced in the REMPI-process are then detected. The use of both an electric and a magnetic field makes it possible to distinguish the REMPI ions from those originating elsewhere, such as plasma ions or photodesorption ions. 145 refs.; 25 figs.; 6 tabs

Spectrometric determination of the species distribution of hydrogen and deuterium in the multi-megawatt ion sources (PINI) of the neutral beam injectors NI-1 and NI-2 of TEXTOR

International Nuclear Information System (INIS)

Rotter, H.; Uhlemann, R.

1990-11-01

The ion species fractions of hydrogen H + , H 2 + , H 3 + and deuterium D + , D 2 + , D 3 + in the extracted beam of the multi-megawatt ion sources (PINI) of the neutral beam injectors of TEXTOR are determined. The measurements are obtained from two grating spectrometers of 0.5 m focal length with a light guiding system of 50 mm aperture using the Doppler shifted H α /D α -light of the accelerated beam particles. The spectral resolution obtained is 0.76 A with a 50 μm entrance slit. The ion source is a bucket source (modified JET PINI) with a multipole magnetic field in checkerboard arrangement. The species fraction measurements are performed as function of beam current, ion source pressure and beam pulse length. The results for hydrogen and deuterium at particle energies of 20-55 keV and beam currents of 13-87 A show no significant difference between neutral injector I and II. For 55 keV and a beam current of 87 A in hydrogen and 63 A in deuterium a species mix of 67.2:24.5:8.4% (H + :H 2 + :H 3 + ) and of 69.1:23.8:7.1% (D + :D 2 + :D 3 + ) is obtained. (orig.) [de

Unusual hydrogen bonding in L-cysteine hydrogen fluoride.

Science.gov (United States)

Minkov, V S; Ghazaryan, V V; Boldyreva, E V; Petrosyan, A M

2015-08-01

L-Cysteine hydrogen fluoride, or bis(L-cysteinium) difluoride-L-cysteine-hydrogen fluoride (1/1/1), 2C3H8NO2S(+)·2F(-)·C3H7NO2S·HF or L-Cys(+)(L-Cys···L-Cys(+))F(-)(F(-)...H-F), provides the first example of a structure with cations of the 'triglycine sulfate' type, i.e. A(+)(A···A(+)) (where A and A(+) are the zwitterionic and cationic states of an amino acid, respectively), without a doubly charged counter-ion. The salt crystallizes in the monoclinic system with the space group P2(1). The dimeric (L-Cys···L-Cys(+)) cation and the dimeric (F(-)···H-F) anion are formed via strong O-H···O or F-H···F hydrogen bonds, respectively, with very short O···O [2.4438 (19) Å] and F···F distances [2.2676 (17) Å]. The F···F distance is significantly shorter than in solid hydrogen fluoride. Additionally, there is another very short hydrogen bond, of O-H···F type, formed by a L-cysteinium cation and a fluoride ion. The corresponding O···F distance of 2.3412 (19) Å seems to be the shortest among O-H···F and F-H···O hydrogen bonds known to date. The single-crystal X-ray diffraction study was complemented by IR spectroscopy. Of special interest was the spectral region of vibrations related to the above-mentioned hydrogen bonds.

Ground state of a hydrogen ion molecule immersed in an inhomogeneous electron gas

International Nuclear Information System (INIS)

Diaz-Valdes, J.; Gutierrez, F.A.; Matamala, A.R.; Denton, C.D.; Vargas, P.; Valdes, J.E.

2007-01-01

In this work we have calculated the ground state energy of the hydrogen molecule, H 2 + , immersed in the highly inhomogeneous electron gas around a metallic surface within the local density approximation. The molecule is perturbed by the electron density of a crystalline surface of Au with the internuclear axis parallel to the surface. The surface spatial electron density is calculated through a linearized band structure method (LMTO-DFT). The ground state of the molecule-ion was calculated using the Born-Oppenheimer approximation for a fixed-ion while the screening effects of the inhomogeneous electron gas are depicted by a Thomas-Fermi like electrostatic potential. We found that within our model the molecular ion dissociates at the critical distance of 2.35a.u. from the first atomic layer of the solid

The effect of hydrogenation on the growth of carbon nanospheres and their performance as anode materials for rechargeable lithium-ion batteries

Science.gov (United States)

Zhao, Shijia; Fan, Yunxia; Zhu, Kai; Zhang, Dong; Zhang, Weiwei; Chen, Shuanglong; Liu, Ran; Yao, Mingguang; Liu, Bingbing

2015-01-01

Hydrogenated carbon nanomaterials exhibit many advantages in both mechanical and electrochemical properties, and thus have a wide range of potential applications. However, methods to control the hydrogenation and the effect of hydrogenation on the microstructure and properties of the produced nanomaterials have rarely been studied. Here we report the synthesis of hydrogenated carbon nanospheres (HCNSs) with different degrees of hydrogenation by a facile solvothermal method, in which C2H3Cl3/C2H4Cl2 was used as the carbon precursor and potassium as the reductant. The hydrogenation level of the obtained nanospheres depends on the reaction temperature and higher temperature leads to lower hydrogenation due to the fact that the breaking of C-H bonds requires more external energy. The reaction temperature also affects the diameter of the HCNSs and larger spheres are produced at higher temperatures. More importantly, the size and the degree of hydrogenation are both critical factors for determining the electrochemical properties of the HCNSs. The nanospheres synthesized at 100 °C have a smaller size and a higher hydrogenation degree and show a capacity of 821 mA h g-1 after 50 cycles, which is significantly higher than that of the HCNSs produced at 150 °C (450 mA h g-1). Our study opens a possible way for obtaining high-performance anode materials for rechargeable lithium-ion batteries.

Bound states of hydrogen-like ions in Debye plasma

International Nuclear Information System (INIS)

Li Bowen; Jiang Jun; Kang Weimin; Yang Ningxuan; Dong Chenzhong

2009-01-01

The plasma screening effects on the energy levels and wave functions of hydrogen-like ions were estimated by using Debye model. The effects on n l(n=1-4, l=0-3) energy levels and wave functions of hydrogen and Fe 25+ ion versus screening lengths λ have been analyzed. Furthermore, the screening effects versus quantum number n and l has been analyzed. The results show that the screening effects increasing as n increasing and decreasing as l increasing. Last, the Eigenergies of isoelectronic series change against screening parameter λ has been discussed, it's shown that the plasma screening effects are decreasing as nuclear charge increasing. (authors)

Laser diagnostics of H- formation in a magnetic multicusp ion source

International Nuclear Information System (INIS)

Young, A.T.; Chen, P.; Kunkel, W.B.; Leung, K.N.; Li, C.Y.; Stutzin, G.C.

1991-05-01

The populations of ground electronic state atomic hydrogen and ground electronic state, vibrationally-rotationally excited hydrogen molecules in a negative hydrogen ion source discharge have been measured using vacuum ultraviolet (VUV) laser absorption spectroscopy. Vibrational states up to v=8 and rotational levels as high as J=15 have been measured. The measurements have been made under a range of discharge conditions. The complete vibrational population distribution for v=1-8, J=1 has been obtained. The vibrational distribution appears to be thermalized and does not exhibit a ''plateau'' at the higher vibrational levels, in contrast to most models of this system. In contrast, the high rotational states are populated suprathermally. These determinations indicate that rotationally excited molecules may play an important role in the production of H minus in these sources. 5 refs., 5 figs

Study of the ionization of H+2 ions in strong laser fields

International Nuclear Information System (INIS)

Odenweller, Matthias

2010-01-01

In the framework of this thesis it has been succeeded to develop a worldwide unique measurement apparatur, by which hydrogen-molecule ions can be ionized by means of short laser pulses and the reaction product kinematically completely measured. For this a detection method following the Coltrims technique, in which both protons and electrons can be detected over the complete spatial angle. The H + 2 ions origin from a high-frequency ion source and are accelerated to 400 keV. This ion beam is overlapped with a 780-nm laser pulse othe pulse length 40 fs. After the reaction the molecule ions fragments either via the dissociation channel H + 2 +nhν→H+H + or via an ionization followed by a Coulomb explosion: H + 2 +nhν→H + +H + +e - . The projectiles are detected after a drift path of about 3 m on an ion detector. For the detection of the electrons a special spectrometer was concipated. In the reaction it comes by the comparatively long pulse length already at low intensities to dissociation processes. The dissociating molecule reaches still during the increasing side of the laser pulse in this way distances, in which the charge-resonance-enhanced-ionization (CREI) can take place. Also the angular distribution of the measured protons lying in a very small angular range around the polarization direction of the laser suggests that CREI is the dominant ionization process. At circular polarization however a netto-acceleration of the electrons perpendicularly to the direction of the electric field at the ionization time takes place, so that the measurement of the electron momenta represents a suited measurement quantity for the study of the ionization process. By this way angular distributions of the electrons relatively to the internuclear axis within the polarization plane could be measured.

Applications of ion implantation for modifying the interactions between metals and hydrogen gas

Science.gov (United States)

Musket, R. G.

1989-04-01

Ion implantations into metals have been shown recently to either reduce or enhance interactions with gaseous hydrogen. Published studies concerned with modifications of these interactions are reviewed and discussed in terms of the mechanisms postulated to explain the observed changes. The interactions are hydrogenation, hydrogen permeation, and hydrogen embrittlement. In particular, the results of the reviewed studies are (a) uranium hydriding suppressed by implantation of oxygen and carbon, (b) hydrogen gettered in iron and nickel using implantation of titanium, (c) hydriding of titanium catalyzed by implanted palladium, (d) tritium permeation of 304L stainless steel reduced using selective oxidation of implanted aluminum, and (e) hydrogen attack of a low-alloy steel accelerated by implantation of helium. These studies revealed ion implantation to be an effective method for modifying the interactions of hydrogen gas with metals.

Investigation of morphological, structural, and mechanical characteristics of Zircaloy-4 irradiated with 3.5 MeV hydrogen ions beam

Science.gov (United States)

Rafique, Mohsin; Butt, M. Z.; Ahmad, Sajjad

2017-09-01

Zircaloy-4 specimens were irradiated with 3.5 MeV hydrogen ions (dose range: 1  ×  1013 H+1 cm-2 to 1  ×  1015 H+1 cm-2) using a Pelletron accelerator. FESEM studies reveal formation of hydrogen micro-bubbles, bubbles induced blisters of irregular shapes, and development of cracks on the specimen surface, as in the case of pure zirconium. However, for the highest irradiation dose of 1  ×  1015 H+1 cm-2, agglomeration of flower-shape blisters is observed. XRD analysis shows that the most preferentially oriented crystallographic plane is (0 0 4) with texture coefficient values 1.832-2.308 depending on the ions dose. Its diffraction peak intensity first decreases with the increase in ions dose up to 5  ×  1013 H+1 cm-2 and later increases up to 1  ×  1015 H+1 cm-2. Opposite is found in case of diffraction peak width. Crystallite size and lattice strain determined by Williamson-Hall analysis display a linear relationship between the two with positive slope. Mechanical strength, namely yield stress (YS), ultimate tensile strength (UTS), and fracture stress (FS), increases sharply with ions dose up to 5  ×  1013 H+1 cm-2. For 1  ×  1014 H+1 cm-2 dose there is a sudden drop of stress to a lowest value and then a slow steady increase in stress up to the highest dose 1  ×  1015 H+1 cm-2. Same pattern is followed by uniform elongation and total elongation. All three stress parameters YS, UTS, and FS follow Inverse Hall-Petch relation.

Setup and proof of principle of SAPIS (Stored Atoms Polarized Ion Source), a novel source of polarized H-/D- ions

International Nuclear Information System (INIS)

Emmerich, R.

2007-01-01

The objective of this work was the setup and the proof-of-principle of a new type of negative polarized hydrogen or deuterium ion source, which is based on the charge-exchange reaction vectorH 0 +Cs 0 →vectorH - +Cs + , as for instance the Colliding-Beams-Source (CBS) at the Cooler Synchrotron COSY in Juelich. In contrast to the CBS, the use of a storage cell for the charge-exchange region promises an increase in H - current by at least an order of magnitude without considerable polarization losses. For these purposes, a new laboratory was equipped and both a polarized hydrogen/deuterium atomic beam source and an intense neutral cesium-beam source have been build-on. A Lambshift polarimeter, which allows the measurement of the nuclear polarization of the atomic as well as ionic beams, was completed with the construction of a new spin-filter. After commissioning and optimizing each of these sources, a storage cell was developed and installed in the charge-exchange region with a magnetic field. Additionally, components for the extraction, detection and analysis of the negative ion beam were installed. Following the decisive proof of principle, investigation of the properties of the storage cell, especially as to H recombination and depolarisation, was begun. Furthermore, a number of software programs was developed for the control and monitoring of different components of the sources as well as a universal measuring software for the complete installation, including the measurement and calculation of the beam polarization. At the same time, the remote control system of the Cologne source of polarized ions LASCO at the FN tandem accelerator was completely modernized. (orig.)

Hydrogen production in the K-Basin ion exchange columns, modules and cartridge filters

International Nuclear Information System (INIS)

1994-01-01

K-Basin uses ion exchange modules and ion exchange (IX) columns for removing radionuclides from the basin water. When the columns and modules are loaded, they are removed from service, drained and stored. After a few IX columns accumulate in storage, they are moved to a burial box. One of the burial box contains 33 columns and the other, six. The radionuclides act on the liquid left within and adhering to the beads to produce hydrogen. This report describes the generation rate, accumulation rate and significance of that accumulation. This summary also highlights those major areas of concern to the external (to Westinghouse Hanford Company [WHC]) reviewers. Appendix H presents the comments made by the external reviewers and, on a separate sheet, the responses to those comments. The concerns regarding the details of the analytical approach, are addressed in Appendix H and in the appropriate section

Hydrogen production in the K-Basin ion exchange columns, modules and cartridge filters

Energy Technology Data Exchange (ETDEWEB)

1994-12-21

K-Basin uses ion exchange modules and ion exchange (IX) columns for removing radionuclides from the basin water. When the columns and modules are loaded, they are removed from service, drained and stored. After a few IX columns accumulate in storage, they are moved to a burial box. One of the burial box contains 33 columns and the other, six. The radionuclides act on the liquid left within and adhering to the beads to produce hydrogen. This report describes the generation rate, accumulation rate and significance of that accumulation. This summary also highlights those major areas of concern to the external (to Westinghouse Hanford Company [WHC]) reviewers. Appendix H presents the comments made by the external reviewers and, on a separate sheet, the responses to those comments. The concerns regarding the details of the analytical approach, are addressed in Appendix H and in the appropriate section.

Spectroscopic measurement of H(1S) and H sub 2 (v double prime ,J double prime ) in an H sup minus ion source plasma

Energy Technology Data Exchange (ETDEWEB)

Stutzin, G.C.

1990-08-01

Low pressure H{sub 2} discharges have been used for some time as sources of H{sup {minus}} ions. These discharges contain many different species of particles which interact with each other and with the walls of the discharge chamber. Models exist that predict the populations of the various species for given macroscopic discharge parameters. However, many of the cross sections and wall catalyzation coefficients are unknown or somewhat uncertain. Therefore, it is of interest to measure the populations of as many of these species as possible, in order to determine the validity of the models. These models predict that H{sup {minus}} is created predominantly by the two-step process of vibrational excitation of hydrogen molecules followed by dissociative attachment of slow electrons to these vibrationally-excited hydrogen molecules. Many different collisional processes must be included in the models to explain the dependence of the various populations upon macroscopic parameters. This work presents results of spectroscopic measurements of the density and translational temperature of hydrogen atoms and of specific rotationally- and vibrationally-excited states of electronic ground-state H{sub 2}, in a discharge optimized for H{sup {minus}} production, as well as conventional measurements of the various charged species within the plasma. The spectroscopic measurements are performed directly by narrowband, single-photon absorption in the vacuum ultraviolet.

Effect of low-energy hydrogen ion implantation on dendritic web silicon solar cells

Science.gov (United States)

Rohatgi, A.; Meier, D. L.; Rai-Choudhury, P.; Fonash, S. J.; Singh, R.

1986-01-01

The effect of a low-energy (0.4 keV), short-time (2-min), heavy-dose (10 to the 18th/sq cm) hydrogen ion implant on dendritic web silicon solar cells and material was investigated. Such an implant was observed to improve the cell open-circuit voltage and short-circuit current appreciably for a number of cells. In spite of the low implant energy, measurements of internal quantum efficiency indicate that it is the base of the cell, rather than the emitter, which benefits from the hydrogen implant. This is supported by the observation that the measured minority-carrier diffusion length in the base did not change when the emitter was removed. In some cases, a threefold increase of the base diffusion length was observed after implantation. The effects of the hydrogen implantation were not changed by a thermal stress test at 250 C for 111 h in nitrogen. It is speculated that hydrogen enters the bulk by traveling along dislocations, as proposed recently for edge-defined film-fed growth silicon ribbon.

Collisions of antiprotons with hydrogen molecular ions

DEFF Research Database (Denmark)

Lühr, Armin Christian; Saenz, Alejandro

2009-01-01

Time-dependent close-coupling calculations of the ionization and excitation cross section for antiproton collisions with molecular hydrogen ions are performed in an impact energy range from 0.5 keV to 10 MeV. The Born-Oppenheimer and Franck-Condon approximations as well as the impact parameter...

Gas phase reactions of protonated 1,3-diphenylpropyne and some isomeric [C15H13]+ ions

OpenAIRE

Bäther, Wolfgang; Kuck, Dietmar; Grützmacher, Hans-Friedrich

1985-01-01

Metastable (3-phenyl-2-propynyl)benzenium ions, generated by electron impact induced fragmentation from the appropriately substituted 1,4-dihydrobenzoic acid, react by loss of ·CH3 and C6H6. The study of deuterated derivatives reveals that hydrogen/deuterium exchanges involving all hydrogen and deuterium atoms precede the fragmentations. The results suggest a skeletal rearrangement by electrophilic ring-closure reactions giving rise to protonated phenylindene and protonated 9,10-methano-9,10-...

Negative ion beam processes

International Nuclear Information System (INIS)

Hayward, T.D.; Lawrence, G.P.; Bentley, R.F.; Malanify, J.J.; Jackson, J.A.

1975-06-01

Los Alamos Scientific Laboratory fiscal year 1975 work on production of intense, very bright, negative hydrogen (H - ), ion beams and conversion of a high-energy (a few hundred MeV) negative beam into a neutral beam are described. The ion source work has used a cesium charge exchange source that has produced H - ion beams greater than or equal to 10 mA (about a factor of 10 greater than those available 1 yr ago) with a brightness of 1.4 x 10 9 A/m 2 -rad 2 (about 18 times brighter than before). The high-energy, neutral beam production investigations have included measurements of the 800-MeV H - -stripping cross section in hydrogen gas (sigma/sub -10/, tentatively 4 x 10 -19 cm 2 ), 3- to 6-MeV H - -stripping cross sections in a hydrogen plasma (sigma/sub -10/, tentatively 2 to 4 x 10 -16 cm 2 ), and the small-angle scattering that results from stripping an 800-MeV H - ion beam to a neutral (H 0 ) beam in hydrogen gas. These last measurements were interrupted by the Los Alamos Meson Physics Facility shutdown in December 1974, but should be completed early in fiscal year 1976 when the accelerator resumes operation. Small-angle scattering calculations have included hydrogen gas-stripping, plasma-stripping, and photodetachment. Calculations indicate that the root mean square angular spread of a 390-MeV negative triton (T - ) beam stripped in a plasma stripper may be as low as 0.7 μrad

Applications of ion implantation for modifying the interactions between metals and hydrogen gas

International Nuclear Information System (INIS)

Musket, R.G.

1989-01-01

Ion implantations into metals have been shown recently to either reduce or enhance interactions with gaseous hydrogen. Published studies concerned with modifications of these interactions are reviewed and discussed in terms of the mechanisms postulated to explain the observed changes. The interactions are hydrogenation, hydrogen permeation and hydrogen embrittlement. In particular, the results of the reviewed studies are 1. uranium hydriding suppressed by implantation of oxygen and carbon, 2. hydrogen gettered in iron and nickel using implantation of titanium, 3. hydriding of titanium catalyzed by implanted palladium, 4. tritium permeation of 304L stainless steel reduced using selective oxidation of implanted aluminum, and 5. hydrogen attack of a low-alloy steel accelerated by implantation of helium. These studies revealed ion implantation to be an effective method for modifying the interactions of hydrogen gas with metals. (orig.)

Helicon plasma generator-assisted surface conversion ion source for the production of H(-) ion beams at the Los Alamos Neutron Science Center.

Science.gov (United States)

Tarvainen, O; Rouleau, G; Keller, R; Geros, E; Stelzer, J; Ferris, J

2008-02-01

The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H(-) ion beams in a filament-driven discharge. In this kind of an ion source the extracted H(-) beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H(-) converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H(-) ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H(-) ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H(-) production (main discharge) in order to further improve the brightness of extracted H(-) ion beams.

Helicon plasma generator-assisted surface conversion ion source for the production of H- ion beams at the Los Alamos Neutron Science Centera)

Science.gov (United States)

Tarvainen, O.; Rouleau, G.; Keller, R.; Geros, E.; Stelzer, J.; Ferris, J.

2008-02-01

The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H- ion beams in a filament-driven discharge. In this kind of an ion source the extracted H- beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H- converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H- ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H- ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H- production (main discharge) in order to further improve the brightness of extracted H- ion beams.

Helicon plasma generator-assisted surface conversion ion source for the production of H- ion beams at the Los Alamos Neutron Science Center

International Nuclear Information System (INIS)

Tarvainen, O.; Rouleau, G.; Keller, R.; Geros, E.; Stelzer, J.; Ferris, J.

2008-01-01

The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H - ion beams in a filament-driven discharge. In this kind of an ion source the extracted H - beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H - converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H - ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H - ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H - production (main discharge) in order to further improve the brightness of extracted H - ion beams

Atomistic Modelling of Materials for Clean Energy Applications : hydrogen generation, hydrogen storage, and Li-ion battery

OpenAIRE

Qian, Zhao

2013-01-01

In this thesis, a number of clean-energy materials for hydrogen generation, hydrogen storage, and Li-ion battery energy storage applications have been investigated through state-of-the-art density functional theory. As an alternative fuel, hydrogen has been regarded as one of the promising clean energies with the advantage of abundance (generated through water splitting) and pollution-free emission if used in fuel cell systems. However, some key problems such as finding efficient ways to prod...

Hydrogen retention properties of polycrystalline tungsten and helium irradiated tungsten

International Nuclear Information System (INIS)

Hino, T.; Koyama, K.; Yamauchi, Y.; Hirohata, Y.

1998-01-01

The hydrogen retention properties of a polycrystalline tungsten and tungsten irradiated by helium ions with an energy of 5 keV were examined by using an ECR ion irradiation apparatus and a technique of thermal desorption spectroscopy, TDS. The polycrystalline tungsten was irradiated at RT with energetic hydrogen ions, with a flux of 10 15 H cm -2 and an energy of 1.7 keV up to a fluence of 5 x 10 18 H cm -2 . Subsequently, the amount of retained hydrogen was measured by TDS. The heating temperature was increased from RT to 1000 C, and the heating rate was 50 C min -1 . Below 1000 C, two distinct hydrogen desorption peaks were observed at 200 C and 400 C. The retained amount of hydrogen was observed to be five times smaller than that of graphite, but the concentration in the implantation layer was comparable with that of graphite. Also, the polycrystalline tungsten was irradiated with 5 keV helium ions up to a fluence of 1.4 x 10 18 He cm -2 , and then re-irradiated with 1.7 keV hydrogen ions. The amount of retained hydrogen in this later experiment was close to the value in the case without prior helium ion irradiation. However, the amount of hydrogen which desorbed around the low temperature peak, 200 C, was largely enhanced. The desorption amount at 200 C saturated for the helium fluence of more than 5 x 10 17 He cm -2 . The present data shows that the trapping state of hydrogen is largely changed by the helium ion irradiation. Additionally, 5 keV helium ion irradiation was conducted on a sample pre-implanted with hydrogen ions to simulate a helium ion impact desorption of hydrogen retained in tungsten. The amount of the hydrogen was reduced as much as 50%. (orig.)

Effect of Cesium and Xenon Seeding in Negative Hydrogen Ion Sources

International Nuclear Information System (INIS)

Bacal, M.; Brunteau, A.M.; Deniset, C.; Elizarov, L.I.; Sube, F.; Tontegode, A.Y.; Whealton, J.H.

1999-01-01

It is well known that cesium seeding in volume hydrogen negative ion sources leads to a large reduction of the extracted electron current and in some cases to the enhancement of the negative ion current. The cooling of the electrons due to the addition of this heavy impurity was proposed as a possible cause of the mentioned observations. In order to verify this assumption, the authors seeded the hydrogen plasma with xenon, which has an atomic weight almost equal to that of cesium. The plasma properties were studied in the extraction region of the negative ion source Camembert III using a cylindrical electrostatic probe while the negative ion relative density was studied using laser photodetachment. It is shown that the xenon mixing does not enhance the negative ion density and leads to the increase of the electron density, while the cesium seeding reduces the electron density

Slow positron beam study of hydrogen ion implanted ZnO thin films

International Nuclear Information System (INIS)

Hu, Yi; Xue, Xudong; Wu, Yichu

2014-01-01

The effects of hydrogen related defect on the microstructure and optical property of ZnO thin films were investigated by slow positron beam, in combination with x-ray diffraction, infrared and photoluminescence spectroscopy. The defects were introduced by 90 keV proton irradiation with doses of 1×10 15 and 1×10 16 ions cm −2 . Zn vacancy and OH bonding (V Zn +OH) defect complex were identified in hydrogen implanted ZnO film by positron annihilation and infrared spectroscopy. The formation of these complexes led to lattice disorder in hydrogen implanted ZnO film and suppressed the luminescence process. - Highlights: • Hydrogen introduced by ion implantation can form hydrogen-related defect complex. • V Zn +OH defect complex is identified by positron annihilation and IR spectroscopy. • Irradiation defects suppress the luminescence process

Z-H Bond Activation in (Di)hydrogen Bonding as a Way to Proton/Hydride Transfer and H2 Evolution.

Science.gov (United States)

Belkova, Natalia V; Filippov, Oleg A; Shubina, Elena S

2018-02-01

The ability of neutral transition-metal hydrides to serve as a source of hydride ion H - or proton H + is well appreciated. The hydride ligands possessing a partly negative charge are proton accepting sites, forming a dihydrogen bond, M-H δ- ⋅⋅⋅ δ+ HX (M=transition metal or metalloid). On the other hand, some metal hydrides are able to serve as a proton source and give hydrogen bond of M-H δ+ ⋅⋅⋅X type (X=organic base). In this paper we analyse recent works on transition-metal and boron hydrides showing i) how formation of an intermolecular complex between the reactants changes the Z-H (M-H and X-H) bond polarity and ii) what is the implication of such activation in the mechanisms of hydrides reactions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low-energy hydrogen flux measurements at the TORTUR tokamak with negative ion conversion

International Nuclear Information System (INIS)

Toledo, Wiebo van.

1990-01-01

The interaction of a tokamak plasma with the vessel wall is one of the most important subjects in thermonuclear research. The information about this interaction is not complete without direct detection of the outward stream of low-energy, down to a few electronvolts, neutral hydrogen or deuterium atoms. The detection of these atoms is the subject of this thesis. An appropriate method to analyse the atoms which are emitted from the edge plasma is to use a time-of-flight analyser. This kind of apparatus selects particles according to their velocities with-out distinguishing between different masses. If these analysers use the Daly-method the lowest measurable energy of the hydrogen atoms is approximately 25 electronvolts. To increase the detection efficiency a new detection method was developed. This new method uses the conversion of hydrogen atoms into H- ions on a cesiated tungsten surface. By this conversion the lowest measurable energy is decreased down to 5 electron-volt. (author). 93 refs.; 44 figs.; 7 tabs

Progress of the ''batman'' RF source for negative hydrogen ions

International Nuclear Information System (INIS)

Frank, P.; Heinemann, B.; Kraus, W.; Probst, F.; Speth, E.; Vollmer, O.; Bucalossi, J.; Trainham, R.

1998-01-01

The aim of a collaboration between CEA Cadarache and IPP Garching is to investigate the ability of an rf source to produce negative-ion current densities compatible with ITER NBI requirements (20 mA/cm 2 D-). A standard PlNI-size rf source developed for ASDEX-Upgrade and a three-grid extraction system form the basis of BATMAN (Bavarian Test Machine for Negative Ions). In the case of a pure hydrogen plasma a current density of 5.5 mA/cm 2 at elevated pressure (2.4 Pa) can be reached. Adding small amounts of argon ( 2 . In the low pressure range (0.7 Pa) the negative ion yield is strongly reduced, but with an admixture of argon and a cesium injection the current density is higher approx. by a factor 8 (4 mA/cm 2 ) compared to the pure hydrogen discharge. The negative ion yield shows a saturation with increasing rf power. (author)

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

Numerical analysis on the ion species ratios in a steady state hydrogen plasma

International Nuclear Information System (INIS)

Fukumasa, Osamu; Saeki, Setsuo; Osaki, Katashi; Sakiyama, Satoshi; Itatani, Ryohei.

1984-07-01

Ion species ratios in a hydrogen plasma are calculated systematically as a function of plasma parameters, i.e. the electron density, the electron temperature, the pressure of hydrogen gas and the plasma volume. Furthermore, in the present analysis, the recombination factor for hydrogen atoms at the wall surface of a vacuum vessel is treated as another plasma parameter. The most significant point is that ion species ratios depend strongly not only on plasma parameters, but also on the recombination factor. The proton ratio increases with decreasing value of the recombination factor. Primary electrons also play an important role for ion species ratios, and the presence of primary electrons causes the proton ratio to decrease. (author)

Electronic excitation in transmission of relativistic H- ions through thin foils

International Nuclear Information System (INIS)

Reinhold, C.O.; Kuerpick, P.; Burgdoerfer, J.; Yoshida, S.

1998-01-01

The authors describe a theoretical model to study the transmission of relativistic H - ions through thin carbon foils. The approach is based on a Monte Carlo solution of the Langevin equation describing electronic excitations of the atoms during the transport through the foil. Calculations for the subshell populations of outgoing hydrogen atoms are found to be in good agreement with recent experimental data on an absolute scale and show that there exists a propensity for populating extreme Stark states

Formation of hydrogen negative ions by surface and volume processes with application to negative ion sources

International Nuclear Information System (INIS)

Hiskes, J.R.

1979-01-01

During the last few decades interest in negative-hydrogen ion sources has been directed mainly toward synchrotron and other particle accelerator applications, with emphasis on high current densities delivered for short pulses. But within the last several years there has been an awareness in the magnetic fusion program of the future need for negative ions as a means for generating high energy neutral beams, beams with energies above a few hundred keV. Negative ions seem to be the only effective intermediary for efficiently producing such beams. Although methods for generating negative ion beams have relied upon synchrotron concepts, the requirements for fusion are very different: here one is interested in more moderate current densities, up to 100 m A cm -2 , but with continuous operation. Proposed source modules would accelerate of the order of 10 A of beam current and deliver several megawatts of beam power. Both H - and D - beams are being considered for application in different reactor systems. The conceptualization of negative ion sources is now in a very volatile stage. But of the great variety of proposals that have been offered to date, three general areas appear ready for development. These are: first, the double charge exchange method for converting a positive ion beam into a negative ion beam; second, electron-volume processes wherein low energy electrons interacting with molecular species lead to negative ion products via dissociative attachment or recombination; and third, generation of negative ions in surface interactions, principally via desorption and backscattering. Both our qualitative and our quantitative understanding of these processes diminishes as one proceeds from the first through the third. The physics of these three methods is considered in detail

Nuclear Spin Effect on Recombination of H3+ Ions with Electrons at 77 K

Science.gov (United States)

Varju, J.; Hejduk, M.; Dohnal, P.; Jílek, M.; Kotrík, T.; Plašil, R.; Gerlich, D.; Glosík, J.

2011-05-01

Utilizing different ratios of para to ortho H2 in normal and para enriched hydrogen, we varied the population of para-H3+ in an H3+ dominated plasma at 77 K. Absorption spectroscopy was used to measure the densities of the two lowest rotational states of H3+. Monitoring plasma decays at different populations of para-H3+ allowed us to determine the rate coefficients for binary recombination of H3+ and ortho-H3+ ions: αbinp(77K)=(1.9±0.4)×10-7cm3s-1 and αbino(77K)=(0.2±0.2)×10-7cm3s-1.

Modeling of H- surface conversion sources; binary (H-Ba) and ternary (H-Cs/W) converter arrangements

International Nuclear Information System (INIS)

van Os, C.F.A.; Kunkel, W.B.; Leguijt, C.; Los, J.

1991-01-01

The production process for the formation of H - ions in a surface conversion source is sputtering of hydrogen atoms from the converter surface layers by incident positive ions, followed by electron attachment via resonant charge exchange with the converter surface. The sputtering process is in direct relation to the converter surface composition. New experimental data led us to identify two different classes of converters: metallic converters, like solid barium(binary) and adlayer converters, like cesium on tungsten (ternary). For a binary converter the hydrogen in the surface layers is directly sputtered by the incoming ions. Consequently, the negative ion yield scales with the hydrogen concentration in the surface layers. In the cesium/tungsten system (ternary) the hydrogen at the surface is believed to be sandwiched between the cesium adlayer and the tungsten surface. Hence, the negative ion yield scales with the sputter coefficient of hydrogen on adsorbed cesium. This is experimentally confirmed

Effects of ion concentration on the hydrogen bonded structure of ...

Indian Academy of Sciences (India)

WINTEC

Effects of ion concentration on the hydrogen bonded structure of water in the vicinity of ions in aqueous NaCl solutions. A NAG. 1. , D CHAKRABORTY and A CHANDRA*. Department of Chemistry, Indian Institute of Technology, Kanpur 208 016. 1. Present address: Department of Chemistry and Chemical Engineering,.

Profiles of plasma parameters and density of negative hydrogen ions by laser detachment measurements in RF-driven ion sources

International Nuclear Information System (INIS)

Christ-Koch, Sina

2007-01-01

This work shows the application of the Laserdetachment method for spatially resolved measurements of negative Hydrogen/Deuterium ion density. It was applied on a high power low pressure RF-driven ion source. The Laser detachment method is based on the measurement of electron currents on a positively biased Langmuir probe before and during/after a laser pulse. The density ratio of negative ions to electrons can be derived from the ratio of currents to the probe. The absolute density of negative ions can be obtained when the electron density is measured with the standard Langmuir probe setup. Measurements with the Langmuir probe additionally yield information about the floating and plasma potential, the electron temperature and the density of positive ions. The Laser detachment setup had to be adapted to the special conditions of the RF-driven source. In particular the existence of RF fields (1 MHz), high source potential (-20 kV), magnetic fields (∝ 7 mT) and caesium inside the source had to be considered. The density of negative ions could be identified in the range of n(H - )=1.10 17 1/m 3 , which is in the same order of magnitude as the electron density. Only the application of the Laser detachment method with the Langmuir probe measurements will yield spatially resolved plasma parameters and H- density profiles. The influence of diverse external parameters, such as pressure, RF-power, magnetic fields on the plasma parameters and their profiles were studied and explained. Hence, the measurements lead to a detailed understanding of the processes inside the source. (orig.)

Status of Charge Exchange Cross Section Measurements for Highly Charged Ions on Atomic Hydrogen

Science.gov (United States)

Draganic, I. N.; Havener, C. C.; Schultz, D. R.; Seely, D. G.; Schultz, P. C.

2011-05-01

Total cross sections of charge exchange (CX) for C5+, N6+, and O7+ ions on ground state atomic hydrogen are measured in an extended collision energy range of 1 - 20,000 eV/u. Absolute CX measurements are performed using an improved merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source mounted on a high voltage platform. In order to improve the problematic H+ signal collection for these exoergic CX collisions at low relative energies, a new double focusing electrostatic analyzer was installed. Experimental CX data are in good agreement with all previous H-oven relative measurements at higher collision energies. We compare our results with the most recent molecular orbital close-coupling (MOCC) and atomic orbital close-coupling (AOCC) theoretical calculations. Work supported by the NASA Solar & Heliospheric Physics Program NNH07ZDA001N, the Office of Fusion Energy Sciences and the Division of Chemical Sciences, Geosciences, and Biosciences, and the Office of Basic Energy Sciences of the U.S. DoE.

H2XP:OH2 Complexes: Hydrogen vs. Pnicogen Bonds

Directory of Open Access Journals (Sweden)

Ibon Alkorta

2016-02-01

Full Text Available A search of the Cambridge Structural Database (CSD was carried out for phosphine-water and arsine-water complexes in which water is either the proton donor in hydrogen-bonded complexes, or the electron-pair donor in pnicogen-bonded complexes. The range of experimental P-O distances in the phosphine complexes is consistent with the results of ab initio MP2/aug’-cc-pVTZ calculations carried out on complexes H2XP:OH2, for X = NC, F, Cl, CN, OH, CCH, H, and CH3. Only hydrogen-bonded complexes are found on the H2(CH3P:HOH and H3P:HOH potential surfaces, while only pnicogen-bonded complexes exist on H2(NCP:OH2, H2FP:OH2, H2(CNP:OH2, and H2(OHP:OH2 surfaces. Both hydrogen-bonded and pnicogen-bonded complexes are found on the H2ClP:OH2 and H2(CCHP:OH2 surfaces, with the pnicogen-bonded complexes more stable than the corresponding hydrogen-bonded complexes. The more electronegative substituents prefer to form pnicogen-bonded complexes, while the more electropositive substituents form hydrogen-bonded complexes. The H2XP:OH2 complexes are characterized in terms of their structures, binding energies, charge-transfer energies, and spin-spin coupling constants 2hJ(O-P, 1hJ(H-P, and 1J(O-H across hydrogen bonds, and 1pJ(P-O across pnicogen bonds.

Extended defects and hydrogen interactions in ion implanted silicon

Science.gov (United States)

Rangan, Sanjay

The structural and electrical properties of extended defects generated because of ion implantation and the interaction of hydrogen with these defects have been studied in this work. Two distinct themes have been studied, the first where defects are a detrimental and the second where they are useful. In the first scenario, transient enhanced diffusion of boron has been studied and correlated with defect evolution studies due to silicon and argon ion implants. Spreading resistance profiles (SRP) correlated with deep level transient spectroscopy (DLTS) measurements, reveal that a low anneal temperatures (TED at low anneal temperatures (550°C, the effect of hydrogen is lost, due to its out-diffusion. Moreover, due to catastrophic out-diffusion of hydrogen, additional damage is created resulting in deeper junctions in hydrogenated samples, compared to the non-hydrogenated ones. Comparing defect evolution due to Si and Ar ion implants at different anneal temperatures, while the type of defects is the same in the two cases, their (defect) dissolution occurs at lower anneal temperatures (˜850°C) for Si implants. Dissolution for Ar implants seems to occur at higher anneal temperatures. The difference has been attributed to the increased number of vacancies created by Ar to that of silicon implant. In second aspect, nano-cavity formation due to vacancy agglomeration has been studied by helium ion implantation and furnace anneal, where the effect of He dose, implant energy and anneal time have been processing parameters that have been varied. Cavities are formed only when the localized concentration of He is greater than 3 x 1020 cm-3. While at high implant doses, a continuous cavity layer is formed, at low implant doses a discontinuous layer is observed. The formation of cavities at low doses has been observed for the first time. Variation of anneal times reveal that cavities are initially facetted (for short anneal times) and tend to become spherical when annealed for

Setup and proof of principle of SAPIS (Stored Atoms Polarized Ion Source), a novel source of polarized H{sup -}/D{sup -} ions; Aufbau und Funktionsnachweis von SAPIS (Stored Atoms Polarized Ion Source), einer neuartigen Quelle polarisierter H{sup -}/D{sup -}-Ionen

Energy Technology Data Exchange (ETDEWEB)

Emmerich, R.

2007-02-14

The objective of this work was the setup and the proof-of-principle of a new type of negative polarized hydrogen or deuterium ion source, which is based on the charge-exchange reaction (vector)H{sup 0}+Cs{sup 0}{yields}(vector)H{sup -}+Cs{sup +}, as for instance the Colliding-Beams-Source (CBS) at the Cooler Synchrotron COSY in Juelich. In contrast to the CBS, the use of a storage cell for the charge-exchange region promises an increase in H{sup -} current by at least an order of magnitude without considerable polarization losses. For these purposes, a new laboratory was equipped and both a polarized hydrogen/deuterium atomic beam source and an intense neutral cesium-beam source have been build-on. A Lambshift polarimeter, which allows the measurement of the nuclear polarization of the atomic as well as ionic beams, was completed with the construction of a new spin-filter. After commissioning and optimizing each of these sources, a storage cell was developed and installed in the charge-exchange region with a magnetic field. Additionally, components for the extraction, detection and analysis of the negative ion beam were installed. Following the decisive proof of principle, investigation of the properties of the storage cell, especially as to H recombination and depolarisation, was begun. Furthermore, a number of software programs was developed for the control and monitoring of different components of the sources as well as a universal measuring software for the complete installation, including the measurement and calculation of the beam polarization. At the same time, the remote control system of the Cologne source of polarized ions LASCO at the FN tandem accelerator was completely modernized. (orig.)

Theoretical examination of the trapping of ion-implanted hydrogen in metals

International Nuclear Information System (INIS)

Myers, S.M.; Nordlander, P.; Besenbacher, F.; Norskov, J.K.

1986-01-01

Theoretical analysis of the defect trapping of ion-implanted hydrogen in metals has been extended in two respects. A new transport formalism has been developed which takes account not only of the diffusion, trapping, and surface release of the hydrogen, which were included in earlier treatments, but also the diffusion, recombination, agglomeration, and surface annihilation of the vacancy and interstitial traps. In addition, effective-medium theory has been used to examine multiple hydrogen occupancy of the vacancy, and, for the fcc structure, appreciable binding enthalpies relative to the solution site have been found for occupancies of up to six. These extensions have been employed to model the depth distribution of ion-implanted hydrogen in Ni and Al during linear ramping of temperature, and the results have been used to interpret previously published data from these metals. The agreement between theory and experiment is good for both systems. In the case of Ni, the two experimentally observed hydrogen-release stages are both accounted for in terms of trapping at vacancies with a binding enthalpy that depends upon occupancy in accord with effective-medium theory

Electrocatalytic hydrogen evolution under densely buffered neutral pH conditions

KAUST Repository

Shinagawa, Tatsuya

2015-08-18

Under buffered neutral pH conditions, solute concentrations drastically influence the hydrogen evolution reaction (HER). The iR-free HER performance as a function of solute concentration was found to exhibit a volcano-shaped trend in sodium phosphate solution at pH 5, with the maximum occurring at 2 M. A detailed microkinetic model that includes calculated activity coefficients, solution resistance, and mass-transport parameters accurately describes the measured values, clarifying that the overall HER performance is predominantly governed by mass-transport of slow phosphate ions (weak acid). In the HER at the optimum concentration of approximately 2 M sodium phosphate at pH 5, our theoretical model predicts that the concentration overpotential accounts for more than half of the required overpotential. The substantial concentration overpotential would originate from the electrolyte property, suggesting that the proper electrolyte engineering will result in an improved apparent HER performances. The significance of concentration overpotential shown in the study is critical in the advancement of electrocatalysis, biocatalysis, and photocatalysis.

Electrocatalytic hydrogen evolution under densely buffered neutral pH conditions

KAUST Repository

Shinagawa, Tatsuya; Takanabe, Kazuhiro

2015-01-01

Under buffered neutral pH conditions, solute concentrations drastically influence the hydrogen evolution reaction (HER). The iR-free HER performance as a function of solute concentration was found to exhibit a volcano-shaped trend in sodium phosphate solution at pH 5, with the maximum occurring at 2 M. A detailed microkinetic model that includes calculated activity coefficients, solution resistance, and mass-transport parameters accurately describes the measured values, clarifying that the overall HER performance is predominantly governed by mass-transport of slow phosphate ions (weak acid). In the HER at the optimum concentration of approximately 2 M sodium phosphate at pH 5, our theoretical model predicts that the concentration overpotential accounts for more than half of the required overpotential. The substantial concentration overpotential would originate from the electrolyte property, suggesting that the proper electrolyte engineering will result in an improved apparent HER performances. The significance of concentration overpotential shown in the study is critical in the advancement of electrocatalysis, biocatalysis, and photocatalysis.

Interspecies Ion Diffusion Studies using DT, DT(3He), and DT(H) Implosions

Science.gov (United States)

Kim, Y.; Herrmann, H. W.; Schmitt, M. J.; Kagan, G.; McEvoy, A. M.; Hoffman, N. M.; Gales, S.; Leatherland, A.; Gatu Johnson, M.; Frenje, J.; Glevov, V. Yu; Forrest, C.

2015-11-01

Anomalous ICF yield degradation has been observed from gas fills containing mixtures (i.e., D(3He), DT(3He), D(Ar), and even DT). Interspecies ion diffusion theory has been suggested as a possible cause resulting from gradient-driven diffusion (i.e., pressure, electric potential, and temperature) which forces lower mass ions away from core and higher mass ions toward core. The theory predicts hydrogen addition to deuterium or tritium should result in increased yield compared to expected yield, which is opposite to 3He addition. At Omega laser facility, we have tested hydro-equivalent fills of DT, DT(3He), and DT(H) with the assumption that same fuel mass and particle pressure will provide identical convergence. Preliminary results verify a factor of 2 yield reduction relative to scaling when 3He added to DT. At DT(H) case, however, no significant yield degradation or a slight yield enhancement was observed which agrees with the interspecies ion diffusion theory. Detailed experiment results and simulation are needed to confirm the initial observation.

Negative hydrogen ion sources for accelerators

Energy Technology Data Exchange (ETDEWEB)

Moehs, D.P.; /Fermilab; Peters, J.; /DESY; Sherman, J.; /Los Alamos

2005-08-01

A variety of H{sup -} ion sources are in use at accelerator laboratories around the world. A list of these ion sources includes surface plasma sources with magnetron, Penning and surface converter geometries as well as magnetic-multipole volume sources with and without cesium. Just as varied is the means of igniting and maintaining magnetically confined plasmas. Hot and cold cathodes, radio frequency, and microwave power are all in use, as well as electron tandem source ignition. The extraction systems of accelerator H{sup -} ion sources are highly specialized utilizing magnetic and electric fields in their low energy beam transport systems to produce direct current, as well as pulsed and/or chopped beams with a variety of time structures. Within this paper, specific ion sources utilized at accelerator laboratories shall be reviewed along with the physics of surface and volume H{sup -} production in regard to source emittance. Current research trends including aperture modeling, thermal modeling, surface conditioning, and laser diagnostics will also be discussed.

Gadolinium-hydrogen ion exchange of zirconium phosphate

Science.gov (United States)

Liu, D. C.; Power, J. L.

1972-01-01

The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

Mechanistic Switching by Hydronium Ion Activity for Hydrogen Evolution and Oxidation over Polycrystalline Platinum Disk and Platinum/Carbon Electrodes

KAUST Repository

Shinagawa, Tatsuya

2014-07-22

Fundamental electrochemical reactions, namely the hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR), are re-evaluated under various pH conditions over polycrystalline Pt disk electrodes and Pt/C electrodes to investigate the overpotential and Tafel relations. Kinetic trends are observed and can be classified into three pH regions: acidic (1-5), neutral (5-9), and alkaline (9-13). Under neutral conditions, in which H2O becomes the primary reactant, substantial overpotential, which is not affected by pH and the supporting electrolyte type, is required for electrocatalysis in both directions. This ion independence, including pH, suggests that HER/HOR performance under neutral conditions solely reflects the intrinsic electrocatalytic activity of Pt in the rate determining steps, which involve electron transfer with water molecules. A global picture of the HER/HOR, resulting from mechanistic switching accompanied by change in pH, is detailed.

A future, intense source of negative hydrogen ions

Science.gov (United States)

Siefken, Hugh; Stein, Charles

1994-01-01

By directly heating lithium hydride in a vacuum, up to 18 micro-A/sq cm of negative hydrogen has been obtained from the crystal lattice. The amount of ion current extracted and analyzed is closely related to the temperature of the sample and to the rate at which the temperature is changed. The ion current appears to be emission limited and saturates with extraction voltage. For a fixed extraction voltage, the ion current could be maximized by placing a grid between the sample surface and the extraction electrode. Electrons accompanying the negative ions were removed by a magnetic trap. A Wein velocity filter was designed and built to provide definitive mass analysis of the extracted ion species. This technique when applied to other alkali hydrides may produce even higher intensity beams possessing low values of emittance.

Modification of structure and optical band-gap of nc-Si:H films with ion irradiation

International Nuclear Information System (INIS)

Zhu Yabin; Wang Zhiguang; Sun Jianrong; Yao Cunfeng; Shen Tielong; Li Bingsheng; Wei Kongfang; Pang Lilong; Sheng Yanbin; Cui Minghuan; Li Yuanfei; Wang Ji; Zhu Huiping

2012-01-01

Hydrogenated nano-crystalline silicon (nc-Si:H) films fabricated by using hot-wire chemical vapor deposition are irradiated at room temperature with 6.0 MeV Xe-ions. The irradiation fluences are 1.0 × 10 13 , 5.0 × 10 13 and 1.0 × 10 14 Xe-ions/cm 2 . The structure and optical band-gap of the irradiated films varying with ion fluence are investigated by means of X-ray diffraction, Raman and UV–Vis–NIR spectroscopes, as well as transmission electron microscopy. It is found that the crystallite size, the crystalline fraction and the optical band-gap decrease continuously with increasing the ion fluence. The crystalline fraction of the films irradiated to the fluences from 0 to 1.0 × 10 14 Xe-ions/cm 2 decreases from about 65.7% to 2.9% and the optical band-gap decreases from about 2.1 to 1.6 eV. Possible origins of the modification of the nc-Si:H films under 6.0 MeV Xe-ions irradiation are briefly discussed.

Kinetics of hydrogen adsorption on MgH{sub 2}/CNT composite

Energy Technology Data Exchange (ETDEWEB)

Rather, Sami ullah, E-mail: rathersami@gmail.com; Taimoor, Aqeel Ahmad; Muhammad, Ayyaz; Alhamed, Yahia Abobakor; Zaman, Sharif Fakhruz; Ali, Arshid Mahmood

2016-05-15

Highlights: • Hydrogen adsorption comparisons of commercial, milled, and MgH{sub 2} composite. • Hydrogen adsorption capacity and kinetics improves tremendously by CNT embedding. • Unsteady state modeling and simulation of adsorption kinetics. - Abstract: Magnesium hydride (MgH{sub 2})–carbon nanotubes (CNT) composite has been prepared by high-energy ball milling method and their experimental and kinetic hydrogen adsorption studies was assessed. Hydrogen adsorption studies were performed by Sievert’s volumetric apparatus and kinetic evaluation was conducted by surface chemistry and Langmuir–Hinshelwood–Hougen–Watson (LHHW) type mode. Powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were performed. Hydrogen adsorption capacity of commercial MgH{sub 2}, milled MgH{sub 2}, and MgH{sub 2}/CNT composite are found to be 0.04, 0.057, and 0.059 g (H{sub 2})/g (MgH{sub 2}) at 673 K and hydrogen pressure of 4.6 MPa. Addition of 5 wt% of CNTs to MgH{sub 2} proved to be very critical to enhance hydrogen adsorption as well as to improve its kinetics. It was observed that hydrogen adsorption is not in quasi-state equilibrium and is modeled using kinetic rate laws.

New approach for the electronic energies of the hydrogen molecular ion

International Nuclear Information System (INIS)

Scott, Tony C.; Aubert-Frecon, Monique; Grotendorst, Johannes

2006-01-01

Herein, we present analytical solutions for the electronic energy eigenvalues of the hydrogen molecular ion H 2 + , namely the one-electron two-fixed-center problem. These are given for the homonuclear case for the countable infinity of discrete states when the magnetic quantum number m is zero, i.e., for 2 Σ + states. In this case, these solutions are the roots of a set of two coupled three-term recurrence relations. The eigensolutions are obtained from an application of experimental mathematics using Computer Algebra as its principal tool and are vindicated by numerical and algebraic demonstrations. Finally, the mathematical nature of the eigenenergies is identified

Hydrogenic fast-ion diagnostic using Balmer-alpha light

International Nuclear Information System (INIS)

Heidbrink, W W; Burrell, K H; Luo, Y; Pablant, N A; Ruskov, E

2004-01-01

Hydrogenic fast-ion populations are common in toroidal magnetic fusion devices, especially in devices with neutral beam injection. As the fast ions orbit around the device and pass through a neutral beam, some fast ions neutralize and emit Balmer-alpha light. The intensity of this emission is weak compared with the signals from the injected neutrals, the warm (halo) neutrals and the cold edge neutrals, but, for a favourable viewing geometry, the emission is Doppler shifted away from these bright interfering signals. Signals from fast ions are detected in the DIII-D tokamak. When the electron density exceeds ∼7 x 10 19 m -3 , visible bremsstrahlung obscures the fast-ion signal. The intrinsic spatial resolution of the diagnostic is ∼5 cm for 40 keV amu -1 fast ions. The technique is well suited for diagnosis of fast-ion populations in devices with fast-ion energies (∼30 keV amu -1 ), minor radii (∼0.6 m) and plasma densities (∼ 20 m -3 ) that are similar to those of DIII-D

Nanostructural evolution and behavior of H and Li in ion-implanted γ-LiAlO 2

Energy Technology Data Exchange (ETDEWEB)

Jiang, Weilin; Zhang, Jiandong; Edwards, Danny J.; Overman, Nicole R.; Zhu, Zihua; Price, Lloyd; Gigax, Jonathan; Castanon, Elizabeth; Shao, Lin; Senor, David J.

2017-10-01

In-situ He+ ion irradiation is performed under a helium ion microscope to study nanostructural evolution in polycrystalline gamma-LiAlO2 pellets. Various locations within a grain, across grain boundaries and at a cavity are selected. The results exhibit He bubble formation, grain-boundary cracking, nanoparticle agglomeration, increasing surface brightness with dose, and material loss from the surface. Similar brightening effects at grain boundaries are also observed under a scanning electron microscope. Li diffusion and loss from polycrystalline gamma-LiAlO2 is faster than its monocrystalline counterpart during H2+ ion implantation at elevated temperatures. There is also more significant H diffusion and release from polycrystalline pellets during thermal annealing of 300 K implanted samples. Grain boundaries and cavities could provide a faster pathway for H and Li diffusion. H release is slightly faster from the 573 K implanted monocrystalline gamma-LiAlO2 during annealing at 773 K. Metal hydrides could be formed preferentially along the grain boundaries to immobilize hydrogen.

Characteristics and dynamics of the boundary layer in RF-driven sources for negative hydrogen ions

International Nuclear Information System (INIS)

Wimmer, Christian

2014-01-01

The design of the neutral beam injection system of the upcoming ITER fusion device is based on the IPP (Max-Planck-Institut fuer Plasmaphysik, Garching) prototype source for negative hydrogen ions. The latter consists of a driver, in which hydrogen (or deuterium) molecules are dissociated in a large degree in a hydrogen plasma; the plasma expands then towards the plasma grid, on which negative hydrogen ions are formed by conversion of atoms or positive ions by the surface process and are extracted in the following accompanied by the co-extraction of electrons via a three grid system. Electrons are removed out of the extracted beam prior full acceleration using deflection magnets, bending them onto the second grid. The thermal load limits the tolerable amount of co-extracted electrons. A magnetic filter field in the expansion chamber reduces the electron temperature and density, on the one hand in order to minimize the destruction process of negative hydrogen ions by electron collisions and on the other hand in order to reduce the co-extracted electron current density. Caesium is evaporated into the source for an effective production of negative hydrogen ions, lowering the work function of the plasma grid. Due to the high chemical reactivity of caesium, the high vacuum condition in the source and the plasma-wall interaction, complex redistribution processes of Cs take place in the ion source. The boundary layer is the plasma volume between the magnetic filter field and the plasma grid, in which the most important physics of the negative ion source takes place: the production of negative hydrogen ions at the plasma grid, their transport through the plasma and the following extraction. A deeper understanding of the plasma and Cs dynamics in the boundary layer is desirable in order to achieve a stable long-pulse operation as well as to identify possible future improvements. For this reason, the boundary layer of the prototype source has been characterized in this work

Use of nuclear reactions and ion channeling techniques for depth profiling hydrogen isotopes in solids

International Nuclear Information System (INIS)

Appleton, B.R.

1979-01-01

Hydrogen has always played a preeminent role in materials science because it so readily alters the physical and chemical properties of materials. However, it is often difficult to determine its role because it is one of the most elusive constituents to detect. More recently hydrogen detection has become necessary in numerous energy-related fields. In fusion energy one must understand plasma particle (hydrogen isotope) recycling, trapping and reemission, as well as the effects of hydrogen on the materials properties of first wall structures in plasma devices (i.e., hydrogen embrittlement, sputtering, blistering, etc.). In geology the presence of hydrogen in various forms alters the mechanical properties of many minerals in the earth's crust and enters directly into studies of tectonic processes. Evaluation of hydrogen in moon rocks increases our understanding of solar wind activity. In solar energy, hydrogen plays an important role in amorphous silicon used in fabricating solar cells. Detection of hydrogen is clearly important in the fossil fuel area. Many of the conventional elemental analysis techniques are not directly applicable to hydrogen determination and others can only detect hydrogen when it is in combination with other elements (i.e., H 2 O, OH, etc.). In this paper we discuss the use of ion beam techniques for obtaining quantitative depth information on hydrogen in materials and discuss the application of these techniques to several problems important in some of the areas mentioned

Nuclear Spin Effect on Recombination of H3+ Ions with Electrons at 77 K

International Nuclear Information System (INIS)

Varju, J.; Hejduk, M.; Dohnal, P.; Jilek, M.; Kotrik, T.; Plasil, R.; Gerlich, D.; Glosik, J.

2011-01-01

Utilizing different ratios of para to ortho H 2 in normal and para enriched hydrogen, we varied the population of para-H 3 + in an H 3 + dominated plasma at 77 K. Absorption spectroscopy was used to measure the densities of the two lowest rotational states of H 3 + . Monitoring plasma decays at different populations of para-H 3 + allowed us to determine the rate coefficients for binary recombination of H 3 + and ortho-H 3 + ions: p α bin (77 K)=(1.9±0.4)x10 -7 cm 3 s -1 and o α bin (77 K)=(0.2±0.2)x 10 -7 cm 3 s -1 .

Mechanism of negative hydrogen ion emission from heated saline hydrides

Energy Technology Data Exchange (ETDEWEB)

Kawano, Hiroyuki; Serizawa, Naoshi; Takeda, Makiko; Hasegawa, Seiji [Ehime Univ., Matsuyama (Japan). Faculty of Science

1997-02-01

To find a clue to the mechanism of negative hydrogen ion emission from a heated sample ({approx}10 mg) of powdery saline hydride (LiH or CaH{sub 2}) deposited on a molybdenum ribbon ({approx}0.1 cm{sup 2}), both the ionic and electronic emission currents were measured as a function of sample temperature ({approx}700 - 800 K), thereby yielding {approx}10{sup -15} - 10{sup -12} A of H{sup -} after mass analysis and {approx}10{sup -7} - 10{sup -5} A of thermal electron. Thermophysical analysis of these data indicates that the desorption energy (E{sup -}) of H{sup -} and work function ({phi}) of the emitting sample surface are 5.1 {+-} 0.3 and 3.1 {+-} 0.2 eV for LiH, respectively, while E{sup -} is 7.7 {+-} 0.3 eV and {phi} is 5.0 {+-} 0.2 eV for CaH{sub 2}. Thermochemical analysis based on our simple model on the emissions indicates that the values of E{sup -} - {phi} are 2.35 and 2.31 eV for LiH and CaH{sub 2}, respectively, which are in fair agreement with the respective values (2.1 {+-} 0.3 and 2.6 {+-} 0.3 eV) determined experimentally. This agreement indicates that the emission of H{sup -} is reasonably explained by our model from the viewpoint of reaction energy. (author)

Hydrogen in amorphous silicon

International Nuclear Information System (INIS)

Peercy, P.S.

1980-01-01

The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

On the influence of hydronium and hydroxide ion diffusion on the hydrogen and oxygen evolution reactions in aqueous media

DEFF Research Database (Denmark)

Wiberg, Gustav Karl Henrik; Arenz, Matthias

2015-01-01

We present a study concerning the influence of the diffusion of H+ and OH- ions on the hydrogen and oxygen evolution reactions (HER and OER) in aqueous electrolyte solutions. Using a rotating disk electrode (RDE), it is shown that at certain conditions the observed current, i.e., the reaction rate...

Influence of hydration on ion-biomolecule interactions: M(+)(indole)(H2O)(n) (M = Na, K; n = 3-6).

Science.gov (United States)

Ke, Haochen; Lisy, James M

2015-10-14

The indole functional group can be found in many biologically relevant molecules, such as neurotransmitters, pineal hormones and medicines. Indole has been used as a tractable model to study the hydration structures of biomolecules as well as the interplay of non-covalent interactions within ion-biomolecule-water complexes, which largely determine their structure and dynamics. With three potential binding sites: above the six- or five-member ring, and the N-H group, the competition between π and hydrogen bond interactions involves multiple locations. Electrostatic interactions from monovalent cations are in direct competition with hydrogen bonding interactions, as structural configurations involving both direct cation-indole interactions and cation-water-indole bridging interactions were observed. The different charge densities of Na(+) and K(+) give rise to different structural conformers at the same level of hydration. Infrared spectra with parallel hybrid functional-based calculations and Gibbs free energy calculations revealed rich structural insights into the Na(+)/K(+)(indole)(H2O)3-6 cluster ion complexes. Isotopic (H/D) analyses were applied to decouple the spectral features originating from the OH and NH stretches. Results showed no evidence of direct interaction between water and the NH group of indole (via a σ-hydrogen bond) at current levels of hydration with the incorporation of cations. Hydrogen bonding to a π-system, however, was ubiquitous at hydration levels between two and five.

Hydrogen constituents of the mesosphere inferred from positive ions - H2O, CH4, H2CO, H2O2, and HCN

Science.gov (United States)

Kopp, E.

1990-01-01

The concentrations in the mesosphere of H2O, CH4, H2CO, H2O2, and HCN were inferred from data on positive ion compositions, obtained from one mid-latitude and four high-latitude rocket flights. The inferred concentrations were found to agree only partially with the ground-based microwave measurements and/or model prediction by Garcia and Solomon (1985). The CH4 concentration was found to vary between 70 and 4 ppb in daytime and 900 and 100 ppbv at night, respectively. Unexpectedly high H2CO concentrations were obtained, with H2CO/H2O ratios between 0.0006 and 0.1, and a mean HCN volume mixing ratio of 6 x 10 to the -10th was inferred.

Note: Development of ESS Bilbao's proton ion source: Ion Source Hydrogen Positive

International Nuclear Information System (INIS)

Miracoli, R.; Feuchtwanger, J.; Arredondo, I.; Belver, D.; Gonzalez, P. J.; Corres, J.; Djekic, S.; Echevarria, P.; Eguiraun, M.; Garmendia, N.; Muguira, L.

2014-01-01

The Ion Source Hydrogen positive is a 2.7 GHz off-resonance microwave discharge ion source. It uses four coils to generate an axial magnetic field in the plasma chamber around 0.1 T that exceeds the ECR resonance field. A new magnetic system was designed as a combination of the four coils and soft iron in order to increase the reliability of the source. The description of the simulations of the magnetic field and the comparison with the magnetic measurements are presented. Moreover, results of the initial commissioning of the source for extraction voltage until 50 kV will be reported

Dissolution of oxalate precipitate and destruction of oxalate ion by hydrogen peroxide in nitric acid solution

International Nuclear Information System (INIS)

Kim, Eung-Ho; Chung, Dong-Yong; Park, Jin-Ho; Yoo, Jae-Hyung

2000-01-01

This study aims at developing an oxalate precipitation process, which is applicable to a partitioning of long-lived radionuclides from the high-level radioactive liquid waste. In order to achieve this, a study for decomposition-reaction of oxalic acid by hydrogen peroxide was first carried out. The decomposition rates of H 2 O 2 and oxalic acid increased with an increase of nitric acid concentration, and especially those decomposition rates steeply increased at more than 2 M HNO 3 . Based on this result, the decomposition kinetics of H 2 O 2 and oxalic acid were suggested in this work. Then, the dissolution of oxalate precipitate and the destruction of oxalate ion in the solution were examined. Oxalate precipitates were prepared by adding oxalic acid into a simulated radioactive waste containing 8 metallic elements. The precipitates obtained thereby were dissolved in various nitric acid concentrations and reacted with H 2 O 2 at 90degC. When the oxalates were completely dissolved, most of the oxalates were decomposed by adding H 2 O 2 , but in a slurry state the decomposition yield of the oxalate decreased with an increase of the slurry density in the solution. Such phenomenon was considered to be due to a catalytic decomposition of H 2 O 2 on a solid surface of oxalate and the decomposition mechanism was explained by a charge transfer from a surface of oxalate solid to H 2 O 2 , producing OH radicals which can destruct H 2 O 2 explosively. Accordingly, the experimental condition for the decomposition of the oxalate precipitates was found to be most favorable at 3 M HNO 3 under the initial concentrations of 0.2 M oxalate and 1 M H 2 O 2 . At 3M HNO 3 , oxalate precipitates could be safely and completely dissolved, and almost decomposed. Additionally, it was observed that the presence of ferric ion in the solution largely affects the decomposition rate of H 2 O 2 . This could be explained by a chain reaction of hydrogen peroxide with ferric ion in the solution

Highly stable hydrogenated gallium-doped zinc oxide thin films grown by DC magnetron sputtering using H2/Ar gas

International Nuclear Information System (INIS)

Takeda, Satoshi; Fukawa, Makoto

2004-01-01

The effects of water partial pressure (P H 2 O ) on electrical and optical properties of Ga-doped ZnO films grown by DC magnetron sputtering were investigated. With increasing P H 2 O , the resistivity (ρ) of the films grown in pure Ar gas (Ar-films) significantly increased due to the decrease in both free carrier density and Hall mobility. The transmittance in the wavelength region of 300-400 nm for the films also increased with increasing P H 2 O . However, no significant P H 2 O dependence of the electrical and optical properties was observed for the films grown in H 2 /Ar gas mixture (H 2 /Ar-films). Secondary ion mass spectrometry (SIMS) and X-ray diffraction (XRD) analysis revealed that hydrogen concentration in the Ar-films increased with increasing P H 2 O and grain size of the films decreases with increasing the hydrogen concentration. These results indicate that the origin of the incorporated hydrogen is attributed to the residual water vapor in the coating chamber, and that the variation of ρ and transmittance along with P H 2 O of the films resulted from the change in the grain size. On the contrary, the hydrogen concentration in H 2 /Ar-films was almost constant irrespective of P H 2 O and the degree of change in the grain size of the films versus P H 2 O was much smaller than that of Ar-films. These facts indicate that the hydrogen primarily comes from H 2 gas and the adsorption species due to H 2 gas preferentially adsorb to the growing film surface over residual water vapor. Consequently, the effects of P H 2 O on the crystal growth are reduced

Experimental investigation of ion cyclotron range of frequencies heating scenarios for ITER's half-field hydrogen phase performed in JET

NARCIS (Netherlands)

Lerche, E.; Van Eester, D.; Johnson, T. J.; Hellsten, T.; Ongena, J.; Mayoral, M. L.; Frigione, D.; Sozzi, C.; Calabro, G.; Lennholm, M.; Beaumont, P.; Blackman, T.; Brennan, D.; Brett, A.; Cecconello, M.; Coffey, I.; Coyne, A.; Crombe, K.; Czarnecka, A.; Felton, R.; Giroud, C.; Gorini, G.; Hellesen, C.; Jacquet, P.; Kiptily, V.; Knipe, S.; Krasilnikov, A.; Maslov, M.; Monakhov, I.; Noble, C.; Nocente, M.; Pangioni, L.; Proverbio, I.; Sergienko, G.; Stamp, M.; Studholme, W.; Tardocchi, M.; Vdovin, V.; Versloot, T.; Voitsekhovitch, I.; Whitehurst, A.; Wooldridge, E.; Zoita, V.; JET-EFDA Contributors,

2012-01-01

Two ion cyclotron range of frequencies (ICRF) heating schemes proposed for the half-field operation phase of ITER in hydrogen plasmas—fundamental H majority and second harmonic 3 He ICRF heating—were recently investigated in JET. Although the same magnetic field and RF frequencies ( f ≈ 42 MHz and f

Radiation-induced segregation at grain boundaries in AL-6XN stainless steels irradiated by hydrogen ions

Science.gov (United States)

Long, Yunxiang; Zheng, Zhongcheng; Guo, Liping; Zhang, Weiping; Shen, Zhenyu; Tang, Rui

2018-04-01

The effect of high concentration of hydrogen on the segregation of radiation-induced segregation (RIS) in AL-6XN stainless steels has been investigated by transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy. Specimens were irradiated with 100 keV H2+ ions from 1 dpa to 5 dpa at 380 °C to investigated the dose dependence of grain boundary RIS. A specimen was irradiated to 5 dpa at 290 °C to study the effect of irradiation temperature. The trends of Cr depletion and Ni enrichment with irradiation dose is similar to that of other austenitic steels reported in the literatures, but the higher concentration of hydrogen made the RIS profile wider. An abnormal phenomenon that the degree of RIS increased with decreasing irradiation temperature was found, indicating that with the retention of hydrogen in the steels, temperature dependence of RIS is dominated by the quantity of retained hydrogen, rather than by thermal segregation processes.

Catalytic activity of γ-irradiated transition metal ions in the decomposition of hydrogen peroxide

International Nuclear Information System (INIS)

Arnikar, H.J.; Kapadi, A.H.; Gohad, A.S.; Bhosale, S.B.

1988-01-01

The catalystic decomposition of hydrogen peroxide by transition metal ions, Fe 2+ , Fe 3+ , Co 2+ and Cu 2+ , adsorbed on neutral α-alumina was studied over the temperature range of 295-313 K. γ-irradiation of the catalysts to a dose of 0.12 MGy enhanced markedly the first order decomposition rate. Negligible in the case of Cu 2+ , the radiation effect increased roughly in the order of the number of unpaired d electrons in these ions: Cu(II), Fe(II), Co(II) and Fe(III). Results are explained on the basis of Kremer's mechanism of electron induced heterogeneous decomposition of H 2 O 2 . The radiation effect is attributed to the initial excess of electrons released from traps in the beginning of the reaction

A novel radial anode layer ion source for inner wall pipe coating and materials modification--hydrogenated diamond-like carbon coatings from butane gas.

Science.gov (United States)

Murmu, Peter P; Markwitz, Andreas; Suschke, Konrad; Futter, John

2014-08-01

We report a new ion source development for inner wall pipe coating and materials modification. The ion source deposits coatings simultaneously in a 360° radial geometry and can be used to coat inner walls of pipelines by simply moving the ion source in the pipe. Rotating parts are not required, making the source ideal for rough environments and minimizing maintenance and replacements of parts. First results are reported for diamond-like carbon (DLC) coatings on Si and stainless steel substrates deposited using a novel 360° ion source design. The ion source operates with permanent magnets and uses a single power supply for the anode voltage and ion acceleration up to 10 kV. Butane (C4H10) gas is used to coat the inner wall of pipes with smooth and homogeneous DLC coatings with thicknesses up to 5 μm in a short time using a deposition rate of 70 ± 10 nm min(-1). Rutherford backscattering spectrometry results showed that DLC coatings contain hydrogen up to 30 ± 3% indicating deposition of hydrogenated DLC (a-C:H) coatings. Coatings with good adhesion are achieved when using a multiple energy implantation regime. Raman spectroscopy results suggest slightly larger disordered DLC layers when using low ion energy, indicating higher sp(3) bonds in DLC coatings. The results show that commercially interesting coatings can be achieved in short time.

Effect of hydrogen ion beam treatment on Si nanocrystal/SiO_2 superlattice-based memory devices

International Nuclear Information System (INIS)

Fu, Sheng-Wen; Chen, Hui-Ju; Wu, Hsuan-Ta; Chuang, Bing-Ru; Shih, Chuan-Feng

2016-01-01

Graphical abstract: - Highlights: • Memory window and retention properties are improved employing HIBAS technique. • The O/Si ratio and radiative recombination are changed by HIBAS. • Memory properties are affected not only by Si NCs and O/Si ratio but also the RDCs. • The mechanism of hydrogen ion beam alters the memory properties is investigated. - Abstract: This study presents a novel route for synthesizing silicon-rich oxide (SRO)/SiO_2 superlattice-based memory devices with an improved memory window and retention properties. The SiO_2 and SRO superlattices are deposited by reactive sputtering. Specifically, the hydrogen ion beam is used to irradiate the SRO layer immediately after its deposition in the vacuum chamber. The use of the hydrogen ion beam was determined to increase oxygen content and the density of the Si nanocrystals. The memory window increased from 16 to 25.6 V, and the leakage current decreased significantly by two orders, to under ±20 V, for the hydrogen ion beam-prepared devices. This study investigates the mechanism into how hydrogen ion beam treatment alters SRO films and influences memory properties.

The molecular hydrogen explorer H2EX

NARCIS (Netherlands)

Boulanger, F.; Maillard, J. P.; Appleton, P.; Falgarone, E.; Lagache, G.; Schulz, B.; Wakker, B. P.; Bressan, A.; Cernicharo, J.; Charmandaris, V.; Drissen, L.; Helou, G.; Henning, T.; Lim, T. L.; Valentjin, E. A.; Abergel, A.; Bourlot, J. Le; Bouzit, M.; Cabrit, S.; Combes, F.; Deharveng, J. M.; Desmet, P.; Dole, H.; Dumesnil, C.; Dutrey, A.; Fourmond, J. J.; Gavila, E.; Grangé, R.; Gry, C.; Guillard, P.; Guilloteau, S.; Habart, E.; Huet, B.; Joblin, C.; Langer, M.; Longval, Y.; Madden, S. C.; Martin, C.; Miville-Deschênes, M. A.; Pineau Des Forêts, G.; Pointecouteau, E.; Roussel, H.; Tresse, L.; Verstraete, L.; Viallefond, F.; Bertoldi, F.; Jorgensen, J.; Bouwman, J.; Carmona, A.; Krause, O.; Baruffolo, A.; Bonoli, C.; Bortoletto, F.; Danese, L.; Granato, G. L.; Pernechele, C.; Rampazzo, R.; Silva, L.; Zotti, G. De; Pardo, J.; Spaans, M.; van der Tak, F. F. S.; Wild, W.; Ferlet, M. J.; Ramsay Howat, S. K.; Smith, M. D.; Swinyard, B.; Wright, G. S.; Joncas, G.; Martin, P. G.; Davis, C. J.; Draine, B. T.; Goldsmith, P. F.; Mainzer, A. K.; Ogle, P.; Rinehart, S. A.; Stacey, G. J.; Tielens, A. G. G. M.

The Molecular Hydrogen Explorer, H2 EX, was proposed in response to the ESA 2015 - 2025 Cosmic Vision Call as a medium class space mission with NASA and CSA participations. The mission, conceived to understand the formation of galaxies, stars and planets from molecular hydrogen, is designed to

Investigation of low-resistivity from hydrogenated lightly B-doped diamond by ion implantation

Directory of Open Access Journals (Sweden)

Cui Xia Yan et al

2008-01-01

Full Text Available We have implanted boron (B ions (dosage: 5×1014 cm-2 into diamond and then hydrogenated the sample by implantating hydrogen ions at room temperature. A p-type diamond material with a low resistivity of 7.37 mΩ cm has been obtained in our experiment, which suggests that the hydrogenation of B-doped diamond results in a low-resistivity p-type material. Interestingly, inverse annealing, in which carrier concentration decreased with increasing annealing temperature, was observed at annealing temperatures above 600 °C. In addition, the formation mechanism of a low-resistivity material has been studied by density functional theory calculation using a plane wave method.

Defects in Cu(InGa)Se2/CdS heterostructure films induced by hydrogen ion implantation

International Nuclear Information System (INIS)

Yakushev, M.V.; Tomlinson, R.D.; Hill, A.E.; Pilkington, R.D.; Mudryi, A.V.; Bondar, I.V.; Victorov, I.A.; Gremenok, V.F.; Shakin, I.A.; Patuk, A.I.

1999-01-01

The influence of H + ion implantation on the photoluminescence properties of Cu(InGa)Se 2 /CdS heterostructures has been studied. This treatment was found to increase the photoluminescence intensity of donor-acceptor band at 1.13 eV because of the passivation by hydrogen atoms of the non-radiative recombination centers on the boundary of Cu(InGa)Se 2 and CdS layers. Two broad bands peaks at 0.96 eV and at 0.82 eV in photoluminescence spectra of ion-implanted Cu(InGa)Se 2 films have been found. The tentative model to explain the origin of the broad photoluminescence bands has been discussed

Production of Long-Lived H2-, HD-, and D2- during Grazing Scattering Collisions of H2+, H3+, D2+, D3+ and D2H+ Ions with KBr, KCl, and LiF Surfaces

International Nuclear Information System (INIS)

Seely, D. G.; Meyer, F. W.; Zhang, H.; Havener, C. C.

2009-01-01

We have investigated atomic and molecular anion production from singly charged atomic and molecular hydrogen, deuterium, and mixed isotope beams during grazing interactions with large area KBr, KCl, and LiF single crystal targets in the incident energy range 4-22.5 keV. Electron capture and, in the case of incident molecular ions, dissociation occur during the grazing interactions without appreciable angular straggling or change in velocity. As a result, atomic and molecular cation and anion interaction products are strongly peaked in the specular reflection direction, and, in case of dissociation products, at the fractional kinetic energies determined by the product fragment mass to incident mass ratios. A large-acceptance electrostatic analysis and detection system is used to collect the charged scattering products with high efficiency. Of particular interest is the production of metastable molecular ions H 2 - , HD - , and D 2 - . By comparing molecular anion yields obtained from incident hydrogen, deuterium and mixed isotope molecular ions, effects arising from isobaric contamination are seen for some incident molecular species.

Hydrogen Storage Characteristics of CNT doped NaAlH4

International Nuclear Information System (INIS)

Pukazhselvan, D.; Sterlin Leo Hudson, M.; Bipin Kumar Gupta; Srivastava, O.N.

2006-01-01

The current Hydrogen based energy infrastructure required a high energy density consumer friendly hydrogen storage media. Although the desired goals for the hydrogen fueled vehicular transport has not yet met by any hydrogen storage material, complex Sodium Alanate is said to be a promising candidate under this demand due to its high hydrogen storage capacity and the thermodynamically permissible reversible hydrogen storage capacity. However its poor sorption behavior under moderate conditions (NaAlH 4 →Na 3 AlH 6 ; 3.7 wt % vs 50 hrs at ∼170 C and Na 3 AlH 6 →NaH; 1.85 wt % vs 30 hrs at ∼220 C) urges their limited uses in ages. But these limitations can be removed by using catalysts particularly transition elements but the location of catalyst in NaAlH 4 matrix and the possible mechanism is not yet clearly understood. The aim of the present investigation is to improve the overall sorption characteristics of NaAlH 4 by a new light weighted high surface area (1315 sq mtr/gm) material (CNT) admixing and to obtain a best doping level to NaAlH 4 . So far only Ti has been attempted as a suitable catalyst. It is believed that the high surface area of CNT can provide an additional solid-gas (H 2 ) surface/interface and it can produce thermal contact between grains (thermal conductivity Kth of MWCNT: 3000 w/k and Kth of NaAlH 4 : 0.32 w/k) for stimulating their thermally activated dissociation in NaAlH 4 . In parallel with this approach XRD of NaAlH 4 reveals that there was no change in lattice structure after doping by CNT, SEM picture depicts that CNT precipitation in grain surfaces. Catalytic concentration of various mole % of x values finds that x = 8 is the best doping level as it gives 3.3 wt % of hydrogen within 2 hrs. The comparative sorption behavior with Ti:NaAlH 4 also shows CNTs as an optimum alternative catalyst to NaAlH 4 and besides this CNT doped desorbed ingredients shown good re-hydrogenation behavior(3.7 wt % at 8. cycle and 4.2 wt % maximum at

Collisions of Beq+ and Bq+ ions with H, H2 and He

International Nuclear Information System (INIS)

Phaneuf, R.A.; Janev, R.K.; Tawara, H.; Kimura, M.; Krstic, P.S.; Peach, G.; Mazing, M.A.

1991-01-01

This Working Group Report discusses the available data on cross sections for collisions of beryllium ions and boron ions with atomic and molecular hydrogen and helium for the purpose of applications for plasma diagnostics and modelling of the plasma edge for low energies, and for plasma diagnostics and energy deposition for high energies. In particular, charge exchange, excitation, ionization and two-electron processes are discussed. 43 refs, 1 tab

RF H-minus ion source development in China spallation neutron source

Science.gov (United States)

Chen, W.; Ouyang, H.; Xiao, Y.; Liu, S.; Lü, Y.; Cao, X.; Huang, T.; Xue, K.

2017-08-01

China Spallation Neutron Source (CSNS) phase-I project currently uses a Penning surface plasma H- ion source, which has a life time of several weeks with occasional sparks between high voltage electrodes. To extend the life time of the ion source and prepare for the CSNS phase-II, we are trying to develop a RF negative hydrogen ion source with external antenna. The configuration of the source is similar to the DESY external antenna ion source and SNS ion source. However several changes are made to improve the stability and the life time. Firstly, Si3N4 ceramic with high thermal shock resistance, and high thermal conductivity is used for plasma chamber, which can endure an average power of 2000W. Secondly, the water-cooled antenna is brazed on the chamber to improve the energy efficiency. Thirdly, cesium is injected directly to the plasma chamber if necessary, to simplify the design of the converter and the extraction. Area of stainless steel exposed to plasma is minimized to reduce the sputtering and degassing. Instead Mo, Ta, and Pt coated materials are used to face the plasma, which makes the self-cleaning of the source possible.

Li2 NH-LiBH4 : a Complex Hydride with Near Ambient Hydrogen Adsorption and Fast Lithium Ion Conduction.

Science.gov (United States)

Wang, Han; Cao, Hujun; Zhang, Weijin; Chen, Jian; Wu, Hui; Pistidda, Claudio; Ju, Xiaohua; Zhou, Wei; Wu, Guotao; Etter, Martin; Klassen, Thomas; Dornheim, Martin; Chen, Ping

2018-01-26

Complex hydrides have played important roles in energy storage area. Here a complex hydride made of Li 2 NH and LiBH 4 was synthesized, which has a structure tentatively indexed using an orthorhombic cell with a space group of Pna2 1 and lattice parameters of a=10.121, b=6.997, and c=11.457 Å. The Li 2 NH-LiBH 4 sample (in a molar ratio of 1:1) shows excellent hydrogenation kinetics, starting to absorb H 2 at 310 K, which is more than 100 K lower than that of pristine Li 2 NH. Furthermore, the Li + ion conductivity of the Li 2 NH-LiBH 4 sample is about 1.0×10 -5  S cm -1 at room temperature, and is higher than that of either Li 2 NH or LiBH 4 at 373 K. Those unique properties of the Li 2 NH-LiBH 4 complex render it a promising candidate for hydrogen storage and Li ion conduction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface Passivation and Junction Formation Using Low Energy Hydrogen Implants

Science.gov (United States)

Fonash, S. J.

1985-01-01

New applications for high current, low energy hydrogen ion implants on single crystal and polycrystal silicon grain boundaries are discussed. The effects of low energy hydrogen ion beams on crystalline Si surfaces are considered. The effect of these beams on bulk defects in crystalline Si is addressed. Specific applications of H+ implants to crystalline Si processing are discussed. In all of the situations reported on, the hydrogen beams were produced using a high current Kaufman ion source.

A novel H2S/H2O2 fuel cell operating at the room temperature

Energy Technology Data Exchange (ETDEWEB)

Sanli, Ayse Elif [Gazi University (Turkey)], email: aecsanli@gmail.com; Aytac, Aylin [Department of Chemistry, Faculty of Science, Gazi University, Teknikokullar (Turkey)], email: aytaca@gazi.edu.tr

2011-07-01

This study concerns the oxidation mechanism of hydrogen sulfide and a fuel cell; acidic peroxide is used as the oxidant and basic hydrogen sulfide is the fuel. A solid state H2S/H2O2 stable fuel cell was produced at room temperature. A cell potential of 0.85 V was reached; this is quite remarkable in comparison to the H2S/O2 fuel cell potential of 0.85 V obtained at 850-1000 degree celsius. The hydrogen sulfide goes through an oxidation reaction in the alkaline fuel cell (H2S/H2O2 fuel cell) which opens up the possibility of using the cheaper nickel as a catalyst. As a result, the fuel cell becomes a potentially low cost technology. A further benefit from using H2S as the alkaline liquid H2S/H2O2 fuel cell, is that sulfide ions are oxidized at the anode, releasing electrons. Sulfur produced reacts with the other sulfide ions and forms disulfide and polysulfide ions in basic electrolytes (such as Black Sea water).

High Growth Rate Deposition of Hydrogenated Amorphous Silicon-Germanium Films and Devices Using ECR-PECVD

Energy Technology Data Exchange (ETDEWEB)

Liu, Yong [Iowa State Univ., Ames, IA (United States)

2002-01-01

Hydrogenated amorphous silicon germanium films (a-SiGe:H) and devices have been extensively studied because of the tunable band gap for matching the solar spectrum and mature the fabrication techniques. a-SiGe:H thin film solar cells have great potential for commercial manufacture because of very low cost and adaptability to large-scale manufacturing. Although it has been demonstrated that a-SiGe:H thin films and devices with good quality can be produced successfully, some issues regarding growth chemistry have remained yet unexplored, such as the hydrogen and inert-gas dilution, bombardment effect, and chemical annealing, to name a few. The alloying of the SiGe introduces above an order-of-magnitude higher defect density, which degrades the performance of the a-SiGe:H thin film solar cells. This degradation becomes worse when high growth-rate deposition is required. Preferential attachment of hydrogen to silicon, clustering of Ge and Si, and columnar structure and buried dihydride radicals make the film intolerably bad. The work presented here uses the Electron-Cyclotron-Resonance Plasma-Enhanced Chemical Vapor Deposition (ECR-PECVD) technique to fabricate a-SiGe:H films and devices with high growth rates. Helium gas, together with a small amount of H₂, was used as the plasma species. Thickness, optical band gap, conductivity, Urbach energy, mobility-lifetime product, I-V curve, and quantum efficiency were characterized during the process of pursuing good materials. The microstructure of the a-(Si,Ge):H material was probed by Fourier-Transform Infrared spectroscopy. They found that the advantages of using helium as the main plasma species are: (1) high growth rate--the energetic helium ions break the reactive gas more efficiently than hydrogen ions; (2) homogeneous growth--heavy helium ions impinging on the surface promote the surface mobility of the reactive radicals, so that heteroepitaxy growth as clustering of Ge and Si, columnar structure are

Hydrogen-related effects in crystalline semiconductors

International Nuclear Information System (INIS)

Haller, E.E.

1988-08-01

Recent experimental and theoretical information regarding the states of hydrogen in crystalline semiconductors is reviewed. The abundance of results illustrates that hydrogen does not preferentially occupy a few specific lattice sites but that it binds to native defects and impurities, forming a large variety of neutral and electrically active complexes. The study of hydrogen passivated shallow acceptors and donors and of partially passivated multivalent acceptors has yielded information on the electronic and real space structure and on the chemical composition of these complexes. Infrared spectroscopy, ion channeling, hydrogen isotope substitution and electric field drift experiments have shown that both static trigonal complexes as well as centers with tunneling hydrogen exist. Total energy calculations indicate that the charge state of the hydrogen ion which leads to passivation dominates, i.e., H + in p-type and H/sup /minus// in n-type crystals. Recent theoretical calculations indicate that is unlikely for a large fraction of the atomic hydrogen to exist in its neutral state, a result which is consistent with the total absence of any Electron Paramagnetic Resonance (EPR) signal. An alternative explanation for this result is the formation of H 2 . Despite the numerous experimental and theoretical results on hydrogen-related effects in Ge and Si there remains a wealth of interesting physics to be explored, especially in compound and alloy semiconductors. 6 refs., 6 figs

Hydrogen isotope exchange reaction rates in tritium, hydrogen and deuterium mixed gases

International Nuclear Information System (INIS)

Uda, Tatsuhiko

1992-01-01

Hydrogen isotope exchange reaction rates in H 2 +T 2 , D 2 +T 2 and H 2 +D 2 +T 2 mixed gases, as induced by tritium decay and beta radiation, were experimentally measured by laser Raman spectrometry. Initially a glass cell was filled with T 2 gas to a pressure of 30-40 kPa, and an equivalent partial pressure of H 2 and/or D 2 was added. The first-order hydrogen isotope exchange reaction rates were 5.54x10 -2 h -1 for H 2 +T 2 mixed gas and 4.76x10 -2 h -1 for D 2 +T 2 . The actual HT producing rate was nearly equivalent to the rate of DT, but the reverse reaction rate of HT was faster than that of DT. The exchange reaction rates between H, D and T showed the isotope effect, HD>HT>DT. The hydrogen isotope exchange reaction rates observed were about twenty times larger than ion formation rates by beta radiation. This result suggests that a free radical chain reaction in hydrogen isotopes is occurring. (orig.)

Volume generation of negative ions in high density hydrogen discharges

International Nuclear Information System (INIS)

Hiskes, J.R.; Karo, A.M.

1983-01-01

A parametric survey is made of a high-density tandem two-chamber hydrogen negative ion system. The optimum extracted negative ion current densities are sensitive to the atom concentration in the discharge and to the system scale length. For scale lengths ranging from 10 cm to 0.1 cm optimum current densities range from of order 1 to 100 mA cm -2 , respectively

Hypothesis for the mechanism of negative ion production in the surface-plasma negative hydrogen ion source

International Nuclear Information System (INIS)

Hiskes, J.R.

1975-01-01

An analysis of the surface-plasma negative hydrogen ion source has shown that the tungsten cathode supports approximately a monolayer of cesium. The backscattering of protons from the cathode as energetic neutrals and the subsequent backscattering of these neutrals from the anode provides for a flux of energetic atoms incident upon the cathode which is comparable to the ion flux. A hypothesis is proposed for the generation of negative ions during the collision of these energetic atoms with the cathode. Several mechanisms for negative ion production by proton collision with the surface are discussed. (U.S.)

{sup 2}H NMR study of phase transition and hydrogen dynamics in hydrogen bonded organic antiferroelectric 55DMBP-H{sub 2}ca

Energy Technology Data Exchange (ETDEWEB)

Asaji, Tetsuo, E-mail: asaji@chs.nihon-u.ac.jp; Hara, Masamichi; Fujimori, Hiroki [Nihon University, Department of Chemistry, College of Humanities and Sciences (Japan); Hagiwara, Shoko [Nihon University, Department of Chemistry, Graduate School of Integrated Basic Sciences (Japan)

2016-12-15

Hydrogen dynamics in one-dimensional hydrogen bonded organic antiferroelectric, co-crystal of 5,5’-dimethyl-2,2’-bipyridine (55DMBP) and chloranilic acid (H{sub 2}ca), was investigated by use of {sup 2}H high resolution solid-state NMR. The two types of hydrogen bonds O-H …N and N{sup +}-H …O{sup −} in the antiferroelectric phase were clearly observed as the splitting of the side band of the {sup 2}H MAS NMR spectra of the acid-proton deuterated compound 55DMBP-D {sub 2}ca. The temperature dependence of the spin-lattice relaxation time was measured of the N{sup +}-H and O-H deuterons, respectively. It was suggested that the motion of the O-H deuteron is already in the antiferroelectric phase in the fast-motion regime in the NMR time scale, while that of the N{sup +}-H deuteron is a slow motion. In the high-temperature paraelectric phase, the both deuterons become equivalent and the fast motion of the deuterons in the NMR time scale is taking place with the activation energy of 7.9 kJ mol{sup −1}.

Hydrogen sulfide: role in ion channel and transporter modulation in the eye

Directory of Open Access Journals (Sweden)

Ya Fatou eNjie-Mbye

2012-07-01

Full Text Available Hydrogen sulfide (H2S, a colorless gas with a characteristic smell of rotten eggs, has been portrayed for decades as a toxic environmental pollutant. Since evidence of its basal production in mammalian tissues a decade ago, H2S has attracted substantial interest as a potential inorganic gaseous mediator with biological importance in cellular functions. Current research suggests that, next to its counterparts nitric oxide and carbon monoxide, H2S is an important multifunctional signaling molecule with pivotal regulatory roles in various physiological and pathophysiological processes as diverse as learning and memory, modulation of synaptic activities, cell survival, inflammation and maintenance of vascular tone in the central nervous and cardiovascular systems. In contrast, there are few reports of a regulatory role of H2S in the eye. Accumulating reports on the pharmacological role of H2S in ocular tissues indicate the existence of a functional trans-sulfuration pathway and a potential physiological role for H2S as a gaseous neuromodulator in the eye. Thus, understanding the role of H2S in vision-related processes is imperative to our expanding knowledge of this molecule as a gaseous mediator in ocular tissues. This review aims to provide a comprehensive and current understanding of the potential role of H2S as a signaling molecule in the eye. This objective is achieved by discussing the involvement of H2S in the regulation of (1 ion channels such as calcium (L-type, T-type and intracellular stores, potassium (KATP and small conductance channels and chloride channels, (2 glutamate transporters such as EAAT1/GLAST and the L-cystine/glutamate antiporter. The role of H2S as an important mediator in cellular functions and physiological processes that are triggered by its interaction with ion channels/transporters in the eye will also be discussed.

A compact rf driven H- ion source for linac injection

International Nuclear Information System (INIS)

Rymer, J.P.; Engeman, G.A.; Hamm, R.W.; Potter, J.M.

1991-01-01

A compact rf driven H - ion source has been developed for use as an injector for the AccSys radio frequency quadrupole (RFQ) linacs. A multicusp magnetic bucket geometry developed at Lawrence Berkeley Laboratory confines the plasma created by an antenna driven by 35 kW (peak) of pulsed rf power at 1.8 MHz. A three electrode system is used to extract and accelerate the H - beam, which is then focused into the RFQ by an einzel lens. Permanent magnets in the extraction region sweep electrons onto the second electrode at energies up to half of the full acceleration voltage. A fast pulsed valve allows the hydrogen gas supply to be pulsed, thus minimizing the average gas flow rate into the system. The design features and performance data from the prototype are discussed

Hydrogen permeation behavior through F82H at high temperature

Energy Technology Data Exchange (ETDEWEB)

Matsuda, S.; Katayama, K.; Shimozori, M.; Fukada, S. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kyushu (Japan); Ushida, H. [Energy Science and Engineering, Faculty of Engineering, Kyushu University, Kyushu (Japan); Nishikawa, M. [Malaysia-Japan International Institute of Technology, UTM, Kuala Lumpur (Malaysia)

2015-03-15

F82H is a primary candidate of structural material and coolant pipe material in a blanket of a fusion reactor. Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 C. degrees because it is considered that F82H can be used up to 30,000 hours at 550 C. degrees. However, it is necessary to assume the situation where F82H is heated over 550 C. degrees in a severe accident. In this study, hydrogen permeation behavior through F82H was investigated in the temperature range from 500 to 800 C. degrees. In some cases, water vapor was added in a sample gas to investigate an effect of water vapor on hydrogen permeation. The permeability of hydrogen in the temperature range from 500 to 700 C. degrees agreed well with the permeability reported by E. Serra et al. The degradation of the permeability by water vapor was not observed. After the hydrogen permeation reached in a steady state at 700 C. degrees, the F82H sample was heated to 800 C. degrees. The permeability of hydrogen through F82H sample which was once heated up to 800 C. degrees was lower than that of the original one. (authors)

Extraction of Carbon Dioxide and Hydrogen from Seawater and Hydrocarbon Production Therefrom

Science.gov (United States)

2016-04-05

acidification of seawater by subjecting the seawater to an ion exchange reaction to exchange H.sup. ions for Na.sup. ions. Carbon dioxide may be...extracted from the acidified seawater. Optionally, the ion exchange reaction can be conducted under conditions which produce hydrogen as well as carbon dioxide . The carbon dioxide and hydrogen may be used to produce hydrocarbons.

Effect of cesium seeding on hydrogen negative ion volume production

International Nuclear Information System (INIS)

Bacal, M.; Balghiti-Sube, F. El; Elizarov, L. I.; Tontegode, A. J.

1998-01-01

The effect of cesium vapor partial pressure on the plasma parameters has been studied in the dc hybrid negative ion source ''CAMEMBERT III.'' The cesium vapor pressure was varied up to 10 -5 Torr and was determined by a surface ionization gauge in the absence of the discharge. The negative ion relative density measured by laser photodetachment in the center of the plasma extraction region increases by a factor of four when the plasma is seeded with cesium. However the plasma density and the electron temperature (determined using a cylindrical electrostatic probe) are reduced by the cesium seeding. As a result, the negative ion density goes up by a factor of two at the lowest hydrogen pressure studied. The velocity of the directed negative ion flow to the plasma electrode, determined from two-laser beam photodetachment experiments, appears to be affected by the cesium seeding. The variation of the extracted negative ion and electron currents versus the plasma electrode bias will also be reported for pure hydrogen and cesium seeded plasmas. The cesium seeding leads to a dramatic reduction of the electron component, which is consistent with the reduced electron density and temperature. The negative ion current is enhanced and a goes through a maximum at plasma electrode bias lower than 1 V. These observations lead to the conclusion that the enhancement of pure volume production occurs in this type of plasma. Possible mechanisms for this type of volume process will be discussed

Hydrogen kinetics studies of MgH2-FeTi composites

Science.gov (United States)

Meena, Priyanka; Jangir, Mukesh; Singh, Ramvir; Sharma, V. K.; Jain, I. P.

2018-05-01

MgH2 + x wt% FeTi (x=10, 25, 50) nano composites were ball milled to get nano structured material and characterized for structural, morphological and thermal properties. XRD of the milled samples revealed the formation of MgH2, FeTi, Fe2Ti and H0.06FeTi phases. Morphological studies by SEM were undertaken to investigate the effect of hydrogenation of nanostructure alloy. EDX confirmed elemental composition of the as-prepared alloy. TGA studies showed higher desorption temperature for milled MgH2 compared to x wt% FeTi added MgH2. Activation energy for hydrogen desorption was found to be -177.90, -215.69, -162.46 and -87.93 kJ/mol for milled MgH2 and Mg2+x wt% FeTi (10, 25, 50), showing 89.97 kJ/ mol reduction in activation energy for 50 wt% alloy additives resulting in improved hydrogen storage capacity. DSC investigations were carried out to investigate the effect of alloy on hydrogen absorption behavior of MgH2.

H2-H2O-HI Hydrogen Separation in H2-H2O-HI Gaseous Mixture Using the Silica Membrane

International Nuclear Information System (INIS)

Pandiangan, Tumpal

2002-01-01

It was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical lS process. Porous alumina tube having pore size of 0.1 μm was modified by chemical vapor deposition using tetraethoxysilane. The permeance single gas of He, H 2 , and N 2 was measured at 300-600 o C. Hydrogen permeance of the modified membrane at a permeation temperature of 600 o C was about 5.22 x 10 -08 mol/Pa m 2 s, and 3.2 x 10 -09 of using gas mixture of H 2 -H 2 O-HI, where as HI permeances was below 1 x 10 -10 mol/Pa m 2 s. The Hydrogen permeance relative was not changed after 25 hours exposure in a mixture of H 2 -H 2 O-HI gas at the temperature of 450 o C. (author)

Hydrogen permeation modification of 4140 steel by ion nitriding with pulsed plasmas

Energy Technology Data Exchange (ETDEWEB)

Bruzzoni, P.; Ortiz, M. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Bruehl, S.P.; Gomez, B.J.A.; Feugeas, J.N. [Inst. de Fisica Rosario (UNR-CONICET), Rosario (Argentina); Nosei, L. [Inst. de Mecanica Aplicada y Estructuras (UNR), Rosario (Argentina)

1998-11-10

It is widely known that the hydrogen in steel produces embrittlement. This effect may cause the failure of the elements (confining walls, mechanical parts, etc.) whose surfaces are in contact with this gas or with processes in which hydrogen is continuously generated. In this work it is shown that the ion nitriding of the surface of AISI 4140 is a good mechanism to act as a barrier against hydrogen permeation in its bulk. The ion nitriding was performed using a square wave DC glow discharge. The development of a compound layer of iron nitrides was observed as the cause of the hydrogen permeation reduction. For equal duration of treatment, thicker compound layers were developed in higher discharge/post-discharge ratios in the square wave of the applied voltage onto the sample (cathode), with a greater reduction of hydrogen permeation coefficient as a consequence. Nevertheless, the permeation was not reduced to zero in any of the treatment conditions used. The results of the analysis of the permeation tests and the image of the photomicrographs showed that the existence of cracks, fractures, failures, etc. in the compound layer (pre-existing in the AISI 4140 steel) could be the cause of the residual hydrogen permeation. This can be attributed to the movement of the hydrogen through these defects diffusing through the original {alpha}-Fe phase of the non-treated steel. (orig.) 11 refs.

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

Science.gov (United States)

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

1981-03-01

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

Negative ion detachment processes

International Nuclear Information System (INIS)

Champion, R.L.; Doverspike, L.D.

1990-10-01

This paper discusses the following topics: H - and D - collisions with atomic hydrogen; collisional decomposition of SF 6 - ; two-electron loss processes in negative ion collisions; associative electron detachment; and negative ion desorption from surfaces

Hydrogen storage stability of nanoconfined MgH2 upon cycling

DEFF Research Database (Denmark)

Huen, Priscilla; Paskevicius, Mark; Richter, Bo

2017-01-01

It is of utmost importance to optimise and stabilise hydrogen storage capacity during multiple cycles of hydrogen release and uptake to realise a hydrogen-based energy system. Here, the direct solvent-based synthesis of magnesium hydride, MgH2, from dibutyl magnesium, MgBu2, in four different...... issues are highlighted relating to the presence of unwanted gaseous by-products, Mg/MgH2 containment within the scaffold, and the purity of the carbon aerogel scaffold. The results presented provide a research path for future researchers to improve the nanoconfinement process for hydrogen storage...... carbon aerogels with different porosities, i.e., pore sizes, 15 hydrogenations, are conducted for each scaffold...

Ion cyclotron resonance heating for tungsten control in various JET H-mode scenarios

Science.gov (United States)

Goniche, M.; Dumont, R. J.; Bobkov, V.; Buratti, P.; Brezinsek, S.; Challis, C.; Colas, L.; Czarnecka, A.; Drewelow, P.; Fedorczak, N.; Garcia, J.; Giroud, C.; Graham, M.; Graves, J. P.; Hobirk, J.; Jacquet, P.; Lerche, E.; Mantica, P.; Monakhov, I.; Monier-Garbet, P.; Nave, M. F. F.; Noble, C.; Nunes, I.; Pütterich, T.; Rimini, F.; Sertoli, M.; Valisa, M.; Van Eester, D.; Contributors, JET

2017-05-01

Ion cyclotron resonance heating (ICRH) in the hydrogen minority scheme provides central ion heating and acts favorably on the core tungsten transport. Full wave modeling shows that, at medium power level (4 MW), after collisional redistribution, the ratio of power transferred to the ions and the electrons vary little with the minority (hydrogen) concentration n H/n e but the high-Z impurity screening provided by the fast ions temperature increases with the concentration. The power radiated by tungsten in the core of the JET discharges has been analyzed on a large database covering the 2013-2014 campaign. In the baseline scenario with moderate plasma current (I p = 2.5 MA) ICRH modifies efficiently tungsten transport to avoid its accumulation in the plasma centre and, when the ICRH power is increased, the tungsten radiation peaking evolves as predicted by the neo-classical theory. At higher current (3-4 MA), tungsten accumulation can be only avoided with 5 MW of ICRH power with high gas injection rate. For discharges in the hybrid scenario, the strong initial peaking of the density leads to strong tungsten accumulation. When this initial density peaking is slightly reduced, with an ICRH power in excess of 4 MW,very low tungsten concentration in the core (˜10-5) is maintained for 3 s. MHD activity plays a key role in tungsten transport and modulation of the tungsten radiation during a sawtooth cycle is correlated to the fishbone activity triggered by the fast ion pressure gradient.

An improved value for the electron affinity of the negative hydrogen ion

International Nuclear Information System (INIS)

Scherk, L.R.

1979-01-01

An expression is derived for the lifetime of a negative ion in a weak and static electric field. Using this expression, existing experimental data are analyzed to improve the empirical value of the electron affinity of the negative hydrogen ion by an order of magnitude. (author)

Flower-like hydrogenated TiO2(B) nanostructures as anode materials for high-performance lithium ion batteries

Science.gov (United States)

Zhang, Zhonghua; Zhou, Zhenfang; Nie, Sen; Wang, Honghu; Peng, Hongrui; Li, Guicun; Chen, Kezheng

2014-12-01

Flower-like hydrogenated TiO2(B) nanostructures have been synthesized via a facile solvothermal approach combined with hydrogenation treatment. The obtained TiO2(B) nanostructures show uniform and hierarchical flower-like morphology with a diameter of 124 ± 5 nm, which are further constructed by primary nanosheets with a thickness of 10 ± 1.2 nm. The Ti3+ species and/or oxygen vacancies are well introduced into the structures of TiO2(B) after hydrogen reduction, resulting in an enhancement in the electronic conductivity (up to 2.79 × 10-3 S cm-1) and the modified surface electrochemical activity. When evaluated for lithium storage capacity, the hydrogenated TiO2(B) nanostructures exhibit enhanced electrochemical energy storage performances compared to the pristine TiO2(B) nanostructures, including high capacity (292.3 mA h g-1 at 0.5C), excellent rate capability (179.6 mA h g-1 at 10C), and good cyclic stability (98.4% capacity retention after 200 cycles at 10C). The reasons for these improvements are explored in terms of the increased electronic conductivity and the facilitation of lithium ion transport arising from the introduction of oxygen vacancies and the unique flower-like morphologies.

Calculation of extracted ion beam particle distribution including within-extractor collisions from H-alpha Doppler shift measurements

International Nuclear Information System (INIS)

Kim, Tae-Seong; Kim, Jinchoon; In, Sang Ryul; Jeong, Seung Ho

2008-01-01

Prototype long pulse ion sources are being developed and tested toward the goal of a deuterium beam extraction of 120 keV/65 A. The latest prototype source consists of a magnetic bucket plasma generator and a four-grid copper accelerator system with multicircular apertures of 568 holes. To measure the angular divergence and the ion species of the ion beam, an optical multichannel analyzer (OMA) system for a Doppler-shifted H-alpha lights was set up at the end of a gas-cell neutralizer. But the OMA data are very difficult to analyze due to a large background level on the top of the three energy peaks (coming from H + , H 2 + , and H 3 + ). These background spectra in the OMA signals seem to result from partially accelerated ion beams in the accelerator. Extracted ions could undergo a premature charge exchange as the accelerator column tends to have a high hydrogen partial pressure from the unused gas from the plasma generator, resulting in a continuous background of partially accelerated beam particles at the accelerator exit. This effect is calculated by accounting for all the possible atomic collision processes and numerically summing up three ion species across the accelerator column. The collection of all the atomic reaction cross sections and the numerical summing up will be presented. The result considerably depends on the background pressure and the ion beam species ratio (H + , H 2 + , and H 3 + ). This effect constitutes more than 20% of the whole particle distribution. And the energy distribution of those suffering from collisions is broad and shows a broad maximum in the vicinity of the half and the third energy region

Hydrogen desorption reactions of Li-N-H hydrogen storage system: Estimation of activation free energy

International Nuclear Information System (INIS)

Matsumoto, Mitsuru; Haga, Tetsuya; Kawai, Yasuaki; Kojima, Yoshitsugu

2007-01-01

The dehydrogenation reactions of the mixtures of lithium amide (LiNH 2 ) and lithium hydride (LiH) were studied under an Ar atmosphere by means of temperature programmed desorption (TPD) technique. The dehydrogenation reaction of the LiNH 2 /LiH mixture was accelerated by addition of 1 mol% Ti(III) species (k = 3.1 x 10 -4 s -1 at 493 K), and prolonged ball-milling time (16 h) further enhanced reaction rate (k = 1.1 x 10 -3 s -1 at 493 K). For the hydrogen desorption reaction of Ti(III) doped samples, the activation energies estimated by Kissinger plot (95 kJ mol -1 ) and Arrhenius plot (110 kJ mol -1 ) were in reasonable agreement. The LiNH 2 /LiH mixture without Ti(III) species, exhibited slower hydrogen desorption process and the kinetic traces deviated from single exponential behavior. The results indicated the Ti(III) additives change the hydrogen desorption reaction mechanism of the LiNH 2 /LiH mixture

Synthetic inorganic ion-exchange materials

International Nuclear Information System (INIS)

Abe, M.

1979-01-01

Exchange isotherms for hydrogen ion/alkali metal ions have been measured at 20 and 40 0 C, with a solution ionic strength of 0.1, in crystalline antimonic(V) acid as a cation-exchanger. The isotherms showed S-shaped curves for the systems of H + /Na + , H + /K + , H + /Rb + and H + /Cs + , but not for H + /Li + exchange. The selectivity coefficients (logarithm scale) vs equivalent fraction of alkali metal ions in the exchanger give linear functions for all systems studied. The selectivity sequences are shown. Overall and hypothetical (zero loading) thermodynamic equilibrium constants were evaluated for these ion-exchange reactions. (author)

Beam diagnostic tools for the negative hydrogen ion source test facility ELISE

International Nuclear Information System (INIS)

Nocentini, Riccardo; Fantz, Ursel; Franzen, Peter; Froeschle, Markus; Heinemann, Bernd; Riedl, Rudolf; Ruf, Benjamin; Wuenderlich, Dirk

2013-01-01

Highlights: ► We present an overview of beam diagnostic tools foreseen for the new testbed ELISE. ► A sophisticated diagnostic calorimeter allows beam profile measurement. ► A tungsten wire mesh in the beam path provides a qualitative picture of the beam. ► Stripping losses and beam divergence are measured by H α Doppler shift spectroscopy. -- Abstract: The test facility ELISE, presently being commissioned at IPP, is a first step in the R and D roadmap for the RF driven ion source and extraction system of the ITER NBI system. The “half-size” ITER-like test facility includes a negative hydrogen ion source that can be operated for 1 h. ELISE is expected to extract an ion beam of 20 A at 60 kV for 10 s every 3 min, therefore delivering a total power of 1.2 MW. The extraction area has a geometry that closely reproduces the ITER design, with the same width and half the height, i.e. 1 m × 1 m. This paper presents an overview of beam diagnostic tools foreseen for ELISE. For the commissioning phase, a simple beam dump with basic diagnostic capabilities has been installed. In the second phase, the beam dump will be substituted by a more sophisticated diagnostic calorimeter to allow beam profile measurement. Additionally, a tungsten wire mesh will be introduced in the beam path to provide a qualitative picture of beam size and position. Stripping losses and beam divergence will be measured by means of H α Doppler shift spectroscopy. An absolute calibration is foreseen in order to measure beam intensity

Hydrogen ion induced ultralow wear of PEEK under extreme load

Science.gov (United States)

Yan, Shuai; Wang, Anying; Fei, Jixiong; Wang, Zhenyang; Zhang, Xiaofeng; Lin, Bin

2018-03-01

As a high-performance engineering polymer, poly(ether ether ketone) (PEEK) is a perfect candidate material for applications under extreme working conditions. However, its high wear rate greatly shortens its service life. In this study, ultralow friction and wear between PEEK and silicon nitride (Si3N4) under extreme-load conditions (with a mean contact pressure above 100 MPa) are found in acid lubricating solutions. Both friction and wear decrease sharply with decreasing pH. At pH = 1, the friction coefficient decreases by an order of magnitude and the wear rate of the PEEK decreases by two orders of magnitude compared to the results with water lubrication. These reductions in friction and wear occur for different speed, load, and surface roughness conditions. The underlying mechanism can be attributed to the formation of hydrogen-ion-induced electrical double layers on the surfaces of PEEK and Si3N4. The combined effect of the resulting repulsive force, electro-viscosity, and low shear strength of the water layer dramatically reduces both friction and wear.

Study of wettability and cell viability of H implanted stainless steel

Science.gov (United States)

Shafique, Muhammad Ahsan; Ahmad, Riaz; Rehman, Ihtesham Ur

2018-03-01

In the present work, the effect of hydrogen ion implantation on surface wettability and biocompatibility of stainless steel is investigated. Hydrogen ions are implanted in the near-surface of stainless steel to facilitate hydrogen bonding at different doses with constant energy of 500 KeV, which consequently improve the surface wettability. Treated and untreated sample are characterized for surface wettability, incubation of hydroxyapatite and cell viability. Contact angle (CA) study reveals that surface wettability increases with increasing H-ion dose. Raman spectroscopy shows that precipitation of hydroxyapatite over the surface increase with increasing dose of H-ions. Cell viability study using MTT assay describes improved cell viability in treated samples as compared to the untreated sample. It is found that low dose of H-ions is more effective for cell proliferation and the cell count decreases with increasing ion dose. Our study demonstrates that H ion implantation improves the surface wettability and biocompatibility of stainless steel.

C-H functionalization: thoroughly tuning ligands at a metal ion, a chemist can greatly enhance catalyst's activity and selectivity.

Science.gov (United States)

Shul'pin, Georgiy B

2013-09-28

This brief essay consists of a few "exciting stories" devoted to relations within a metal-complex catalyst between a metal ion and a coordinated ligand. When, as in the case of a human couple, the rapport of the partners is cordial and a love cements these relations, a chemist finds an ideal married couple, in other words he obtains a catalyst of choice which allows him to functionalize C-H bonds very efficiently and selectively. Examples of such lucky marriages in the catalytic world of ions and ligands are discussed here. Activity of the catalyst is characterized by turnover number (TON) or turnover frequency (TOF) as well as by yield of a target product. Introducing a chelating N,N- or N,O-ligand to the catalyst molecule (this can be an iron or manganese derivative) sharply enhances its activity. However, the activity of vanadium derivatives (with additionally added to the solution pyrazinecarboxylic acid, PCA) as well as of various osmium complexes does not dramatically depend on the nature of ligands surrounding metal ions. Complexes of these metals are very efficient catalysts in oxidations with H2O2. Osmium derivatives are record-holders exhibiting extremely high TONs whereas vanadium complexes are on the second position. Finally, elegant examples of alkane functionalization on the ions of non-transition metals (aluminium, gallium etc.) are described when one ligand within the metal complex (namely, hydroperoxyl ligand HOO(-)) helps other ligand of this complex (H2O2 molecule coordinated to the metal) to disintegrate into two species, generating very reactive hydroxyl radical. Hydrogen peroxide molecule, even ligated to the metal ion, is perfectly stable without the assistance of the neighboring HOO(-) ligand. This ligand can be easily oxidized donating an electron to its partner ligand (H2O2). In an analogous case, when the central ion in the catalyst is a transition metal, this ion changing its oxidation state can donate an electron to the coordinated H2O2

Hydrogenated TiO{sub 2} nanobelts as highly efficient photocatalytic organic dye degradation and hydrogen evolution photocatalyst

Energy Technology Data Exchange (ETDEWEB)

Tian, Jian [School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); State key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Leng, Yanhua [State key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Cui, Hongzhi, E-mail: cuihongzhi1965@163.com [School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); Liu, Hong, E-mail: hongliu@sdu.edu.cn [State key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China)

2015-12-15

Highlights: • A facile synthesis of hydrogenated TiO{sub 2} nanobelts is reported. • Utilizing UV and visible light in photocatalytic degradation and H{sub 2} production. • The improved photocatalytic property is owe to Ti{sup 3+} ions and oxygen vacancies. - Abstract: TiO{sub 2} nanobelts have gained increasing interest because of its outstanding properties and promising applications in a wide range of fields. Here we report the facile synthesis of hydrogenated TiO{sub 2} (H-TiO{sub 2}) nanobelts, which exhibit excellent UV and visible photocatalytic decomposing of methyl orange (MO) and water splitting for hydrogen production. The improved photocatalytic property can be attributed to the Ti{sup 3+} ions and oxygen vacancies in TiO{sub 2} nanobelts created by hydrogenation. Ti{sup 3+} ions and oxygen vacancies can enhance visible light absorption, promote charge carrier trapping, and hinder the photogenerated electron–hole recombination. This work offers a simple strategy for the fabrication of a wide solar spectrum of active photocatalysts, which possesses significant potential for more efficient photodegradation, photocatalytic water splitting, and enhanced solar cells using sunlight as light source.

Hydrogen Temperature-Programmed Desorption (H2 TPD) of Supported Platinum Catalysts.

NARCIS (Netherlands)

Koningsberger, D.C.; Miller, J.T.; Meyers, B.L.; Modica, F.S.; Lane, G.S.; Vaarkamp, M.

1993-01-01

Hydrogen temperature-programmed desorption (TPD) of supported platinum catalysts, Pt/KLTL, Pt/H-LTL, Pt/K-MAZ, Pt/H-MAZ, Pt/-Al2O3, and Pt/SiO2, was performed after hydrogen reduction at 300, 450, or 650°C. For all catalysts, reversible desorption of chemisorbed hydrogen occurred at approximately

Synergistic methane formation kinetics for hydrogen impact on carbon

International Nuclear Information System (INIS)

Haasz, A.A.; Davis, J.W.

1986-06-01

A physical/chemical model is presented for the reaction kinetics for methane formation from carbon, due to bombardment by energetic (∼ 100's eV) H + ions and thermal (∼ 1 eV) H 0 atoms. While the model was developed for H + and H 0 , it can be readily applied to non-hydrogenic energetic particles (ions or atoms, e.g., Ar + , He + , He) in combination with thermal (∼ 1 eV) hydrogen (again ions or atoms) impacting on carbon. Both collisional (in the case of the energetic particles) and chemical reaction processes are included. Special cases of sub-eV H 0 alone, energetic H + alone and combined H 0 plus H + were considered and fitted to experimental data. Generally good agreement was found between theoretical predictions and experimental results over the experimental flux and H + energy ranges studied (H 0 flux: 6x10 14 - 7x10 15 H 0 /cm 2 s, H + flux: 6x10 12 - 5x10 15 H + /cm 2 s, H + energy: 300 eV/H + and 1 keV/H + )

H/D Isotope Effects in Hydrogen Bonded Systems

Directory of Open Access Journals (Sweden)

Aleksander Filarowski

2013-04-01

Full Text Available An extremely strong H/D isotope effect observed in hydrogen bonded A-H…B systems is connected with a reach diversity of the potential shape for the proton/deuteron motion. It is connected with the anharmonicity of the proton/deuteron vibrations and of the tunneling effect, particularly in cases of short bridges with low barrier for protonic and deuteronic jumping. Six extreme shapes of the proton motion are presented starting from the state without possibility of the proton transfer up to the state with a full ionization. The manifestations of the H/D isotope effect are best reflected in the infra-red absorption spectra. A most characteristic is the run of the relationship between the isotopic ratio nH/nD and position of the absorption band shown by using the example of NHN hydrogen bonds. One can distinguish a critical range of correlation when the isotopic ratio reaches the value of ca. 1 and then increases up to unusual values higher than . The critical range of the isotope effect is also visible in NQR and NMR spectra. In the critical region one observes a stepwise change of the NQR frequency reaching 1.1 MHz. In the case of NMR, the maximal isotope effect is reflected on the curve presenting the dependence of Δd (1H,2H on d (1H. This effect corresponds to the range of maximum on the correlation curve between dH and ΔpKa that is observed in various systems. There is a lack in the literature of quantitative information about the influence of isotopic substitution on the dielectric properties of hydrogen bond except the isotope effect on the ferroelectric phase transition in some hydrogen bonded crystals.

Electrotransport of hydrogen in aluminium at 20 and 800 deg C

International Nuclear Information System (INIS)

Byalik, O.M.; Volkotrub, N.P.; Pinchuk, V.M.; Golub, L.V.; Degtyarenko, G.E.; Ivanchuk, D.F.

1982-01-01

Electrotransport of hydrogen in the field of crystal lattice of aluminium is investigated at the special installation using the method of measurement of electric resistivity. Quantum-mechanical calculation of H + and H - ions interaction with aluminium atoms is made to clarify the mechanizm of electrotransport. It is shown, that probability of the H + and H - ions permeation in the field of aluminium crystal lattice can be judged by the ratio of δE 1 (the lattice potential barrier) and δ 2 (the local energy minium in the case of atom arrangement in the lattice plane). The value of potentials of hydrogen ions interaction with aluminium lattice is obtained in the result os solution of the Schroedinger equation

Neutral hydrogen from the foil-induced dissociation of 4HeH+, 3HeH+, and H2+

International Nuclear Information System (INIS)

Cooney, P.J.; Gemmell, D.S.; Kanter, E.P.; Pietsch, W.J.; Zabransky, B.J.

1979-01-01

High resolution energy spectra and angular distributions of H 0 from the dissociation of 4 HeH + , 3 HeH + , and H 2 + in thin carbon foils are presented for incident ion energies ranging from 170 to 1800 keV/amu. For the range of dwell times inside the target foils studied (about 1 to 10 fsec), the dominant mechanism for such dissociation is the Coulomb explosion of the ions inside the target followed by electron capture near the rear surface of the foil. At the shortest of these dwell times, the yield of H 0 for incident ions oriented perpendicular to the beam relative to that for ions aligned with the beam is a factor of two greater than at longer dwell times. These data indicate that, for ion fragments which emerge from the rear surface of the target within a few angstroms of one another, those in the perpendicular orientation have a greater electron capture probability than those emerging in other orientations. 9 references

Novel Hydrogen Compounds from a Potassium Carbonate Electrolytic Cell

International Nuclear Information System (INIS)

Mills, Randell L.

2000-01-01

Novel compounds containing hydrogen in new hydride and polymeric states that demonstrate novel hydrogen chemistry have been isolated following the electrolysis of a K 2 CO 3 electrolyte with the production of excess energy. Inorganic hydride clusters K[KH KHCO 3 ] n + and hydrogen polymer ions such as OH 23 + and H 16 - were identified by time-of-flight secondary ion mass spectroscopy. The presence of compounds containing new states of hydrogen was confirmed by X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, and proton nuclear magnetic resonance spectroscopy

Fabrication of SGOI material by oxidation of an epitaxial SiGe layer on an SOI wafer with H ions implantation

International Nuclear Information System (INIS)

Cheng Xinli; Chen Zhijun; Wang Yongjin; Jin Bo; Zhang Feng; Zou Shichang

2005-01-01

SGOI materials were fabricated by thermal dry oxidation of epitaxial H-ion implanted SiGe layers on SOI wafers. The hydrogen implantation was found to delay the oxidation rate of SiGe layer and to decrease the loss of Ge atoms during oxidation. Further, the H implantation did not degrade the crystallinity of SiGe layer during fabrication of the SGOI

Ion beam investigation of hydrogen implanted in magnesium

International Nuclear Information System (INIS)

Chami, A.-C.

1977-01-01

The diffusion mechanism for hydrogen implanted in magnesium was investigated by nuclear reaction analysis or channeling. The hydrogen introduced is then in the presence of radiation defects created by implantation. The H( 11 B,α) reaction used allowed the profiles of implanted hydrogen to be drawn. The Winterbon calculations derived from LSS theory (Lindhard, Scharff, Schiott) were used. LSS profiles folding and the excitation curve unfolding give very same results. An analysis of the profile of the defects and the evaluation of the total number of Frenkel pairs produced show that the defects are isolated when low energy light elements are implanted, and hydrogen interactions are effected through point defects. A channeling analysis shows that hydrogen occupies tetrahedral sites as far as the temperature remains lower that the migration temperature (about 100K). Beyonds this temperature, the hydrogen migrates and is trapped on motionless defects [fr

H2O2 assisted room temperature oxidation of Ti2C MXene for Li-ion battery anodes

KAUST Repository

Ahmed, Bilal

2016-03-08

Herein we demonstrate that a prominent member of the MXene family, Ti2C, undergoes surface oxidation at room temperature when treated with hydrogen peroxide (H2O2). The H2O2 treatment results in opening up of MXene sheets and formation of TiO2 nanocrystals on their surface, which is evidenced by the high surface area of H2O2 treated MXene and X-ray diffraction (XRD) analysis. We show that the reaction time and the amount of hydrogen peroxide used are the limiting factors, which determine the morphology and composition of the final product. Furthermore, it is shown that the performance of H2O2 treated MXene as an anode material in Li ion batteries (LIBs) was significantly improved as compared to as-prepared MXenes. For instance, after 50 charge/discharge cycles, specific discharge capacities of 389 mA h g−1, 337 mA h g−1 and 297 mA h g−1 were obtained for H2O2 treated MXene at current densities of 100 mA g−1, 500 mA g−1 and 1000 mA g−1, respectively. In addition, when tested at a very high current density, such as 5000 mA g−1, the H2O2 treated MXene showed a specific capacity of 150 mA h g−1 and excellent rate capability. These results clearly demonstrate that H2O2 treatment of Ti2C MXene improves MXene properties in energy storage applications, such as Li ion batteries or capacitors.

H2O2 assisted room temperature oxidation of Ti2C MXene for Li-ion battery anodes

KAUST Repository

Ahmed, Bilal; Anjum, Dalaver H.; Hedhili, Mohamed N.; Gogotsi, Yury; Alshareef, Husam N.

2016-01-01

Herein we demonstrate that a prominent member of the MXene family, Ti2C, undergoes surface oxidation at room temperature when treated with hydrogen peroxide (H2O2). The H2O2 treatment results in opening up of MXene sheets and formation of TiO2 nanocrystals on their surface, which is evidenced by the high surface area of H2O2 treated MXene and X-ray diffraction (XRD) analysis. We show that the reaction time and the amount of hydrogen peroxide used are the limiting factors, which determine the morphology and composition of the final product. Furthermore, it is shown that the performance of H2O2 treated MXene as an anode material in Li ion batteries (LIBs) was significantly improved as compared to as-prepared MXenes. For instance, after 50 charge/discharge cycles, specific discharge capacities of 389 mA h g−1, 337 mA h g−1 and 297 mA h g−1 were obtained for H2O2 treated MXene at current densities of 100 mA g−1, 500 mA g−1 and 1000 mA g−1, respectively. In addition, when tested at a very high current density, such as 5000 mA g−1, the H2O2 treated MXene showed a specific capacity of 150 mA h g−1 and excellent rate capability. These results clearly demonstrate that H2O2 treatment of Ti2C MXene improves MXene properties in energy storage applications, such as Li ion batteries or capacitors.

RBS/channeling analysis of hydrogen-implanted single crystals of FZ silicon and 6H silicon

International Nuclear Information System (INIS)

Irwin, R.B.

1984-01-01

Single crystals of FZ silicon and 6H silicon carbide were implanted with hydrogen ions (50 and 80 keV, respectively) to fluences from 2 x 10 16 H + /cm 2 to 2 x 10 18 H+/cm 2 . The implantations were carried out at three temperatures: approx.95K, 300 K, and approx.800 K. Swelling of the samples was measured by surface profilometry. RBS/channeling was used to obtain the damage profiles and to determine the amount of hydrogen retained in the lattice. The damage profiles are centered around X/sub m/ for the implants into silicon and around R/sub p/ for silicon carbide. For silicon carbide implanted at 95 K and 300 K and for silicon implanted at 95 K, the peak damage region is amorphous for fluences above 8 x 10 16 H + /cm 2 , 4 x 10 17 H + /cm 2 , and 2 x 10 17 H + /cm 2 , respectively. Silicon implanted at 300 and 800 K and silicon carbide implanted at 800 K remain crystalline up to fluences of 1 x 10 18 H + /cm 2 . The channeling damage results agree with previously reported TEM and electron diffraction data. The predictions of a simple disorder-accumulation model with a linear annealing term explains qualitatively the observed damage profiles in silicon carbide. Quantitatively, however, the model predicts faster development of the damage profiles than is observed at low fluences in both silicon and silicon carbide. For samples implanted at 300 and 800 K, the model also predicts substantially less peak disorder than is observed. The effect of the surface, the retained hydrogen, the shape of S/sub D/(X), and the need for a nonlinear annealing term may be responsible for the discrepancy

Improved beam extraction for a negative hydrogen ion source for the LHC injector chain upgrade, Linac4

CERN Document Server

Midttun, Øystein; Scrivens, Richard

In the scope of an upgrade of the injector chain of CERN’s accelerator complex, a new linear accelerator, Linac4, is under construction. This accelerator will replace the existing 50 MeV proton linac, Linac2. By increasing the beam energy to 160 MeV, Linac4 makes it possible to double the brightness in the PSB, and ultimately increase the luminosity in the LHC. Linac4 will accelerate beams of negative hydrogen (H-) to be injected into the PSB by multi-turn, charge exchange injection. The ion source was initially based on the non-caesiated RF-volume source from DESY. However, the beam extraction from this source could not handle the 45 keV beam energy required by the RFQ. A new beam extraction system has therefore been designed, via IBSimu simulations [1], to extract and transport the H- ion beam respecting the Linac4 requirements. Key features of the extraction system is a tuneable puller voltage to adapt the extraction field to the ion and electron beam currents, and a magnetized Einzel lens to dump the co...

Kinetic method of ruthenium ion traces determination, basing on the reaction of oxidation of direct blue 6B, by means of hydrogen peroxide

International Nuclear Information System (INIS)

Suwinska, T.; Gregorowicz, A.; Matysek-Majewska, D.

1980-01-01

A sensitive and selective method of determination of ruthenium ion traces (1.10 - 3 μg/cm 3 ) has been worked out. The method is based on oxidation of direct blue 6B by hydrogen peroxide under acidic conditions at pH = 0,8 - 1,2 in the presence of ruthenium ions as catalyst. The method has been applied for determination of ruthenium traces in Pt, PdCl 2 , PtCl 4 and RhCl 3 .n H 2 O. In these materials ruthenium has been determined within the range of 1,10 - 2 % - 5,10 - 4 %. (author)

HERSCHEL SURVEY OF GALACTIC OH{sup +}, H{sub 2}O{sup +}, AND H{sub 3}O{sup +}: PROBING THE MOLECULAR HYDROGEN FRACTION AND COSMIC-RAY IONIZATION RATE

Energy Technology Data Exchange (ETDEWEB)

Indriolo, Nick; Neufeld, D. A. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Gerin, M.; Falgarone, E. [LERMA, Observatoire de Paris, Ecole Normale Supérieure, PSL Research University, CNRS, UMR8112, F-75014 Paris (France); Schilke, P.; Chambers, E. T.; Ossenkopf, V. [I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Benz, A. O. [Institute of Astronomy, ETH Zürich (Switzerland); Winkel, B.; Menten, K. M. [MPI für Radioastronomie, Bonn (Germany); Black, John H.; Persson, C. M. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Bruderer, S.; Van Dishoeck, E. F. [Max Planck Institut für Extraterrestrische Physik, Garching (Germany); Godard, B.; Lis, D. C. [Sorbonne Universités, UPMC Univ. Paris 06, UMR8112, LERMA, F-75005 Paris (France); Goicoechea, J. R. [Instituto de Ciencias de Materiales de Madrid (CSIC), E-28049 Cantoblanco, Madrid (Spain); Gupta, H. [California Institute of Technology, Pasadena, CA 91125 (United States); Sonnentrucker, P. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Van der Tak, F. F. S. [SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen (Netherlands); and others

2015-02-10

In diffuse interstellar clouds the chemistry that leads to the formation of the oxygen-bearing ions OH{sup +}, H{sub 2}O{sup +}, and H{sub 3}O{sup +} begins with the ionization of atomic hydrogen by cosmic rays, and continues through subsequent hydrogen abstraction reactions involving H{sub 2}. Given these reaction pathways, the observed abundances of these molecules are useful in constraining both the total cosmic-ray ionization rate of atomic hydrogen (ζ{sub H}) and molecular hydrogen fraction (f{sub H{sub 2}}). We present observations targeting transitions of OH{sup +}, H{sub 2}O{sup +}, and H{sub 3}O{sup +} made with the Herschel Space Observatory along 20 Galactic sight lines toward bright submillimeter continuum sources. Both OH{sup +} and H{sub 2}O{sup +} are detected in absorption in multiple velocity components along every sight line, but H{sub 3}O{sup +} is only detected along 7 sight lines. From the molecular abundances we compute f{sub H{sub 2}} in multiple distinct components along each line of sight, and find a Gaussian distribution with mean and standard deviation 0.042 ± 0.018. This confirms previous findings that OH{sup +} and H{sub 2}O{sup +} primarily reside in gas with low H{sub 2} fractions. We also infer ζ{sub H} throughout our sample, and find a lognormal distribution with mean log (ζ{sub H}) = –15.75 (ζ{sub H} = 1.78 × 10{sup –16} s{sup –1}) and standard deviation 0.29 for gas within the Galactic disk, but outside of the Galactic center. This is in good agreement with the mean and distribution of cosmic-ray ionization rates previously inferred from H{sub 3}{sup +} observations. Ionization rates in the Galactic center tend to be 10-100 times larger than found in the Galactic disk, also in accord with prior studies.

Plasma ignition and steady state simulations of the Linac4 H$^{-}$ ion source

CERN Document Server

Mattei, S; Yasumoto, M; Hatayama, A; Lettry, J; Grudiev, A

2014-01-01

The RF heating of the plasma in the Linac4 H- ion source has been simulated using an Particle-in-Cell Monte Carlo Collision method (PIC-MCC). This model is applied to investigate the plasma formation starting from an initial low electron density of 1012 m-3 and its stabilization at 1018 m-3. The plasma discharge at low electron density is driven by the capacitive coupling with the electric field generated by the antenna, and as the electron density increases the capacitive electric field is shielded by the plasma and induction drives the plasma heating process. Plasma properties such as e-/ion densities and energies, sheath formation and shielding effect are presented and provide insight to the plasma properties of the hydrogen plasma.

Atomic reaction rates in H- and D- plasmas

International Nuclear Information System (INIS)

Hiskes, J.R.; Bacal, M.; Hamilton, G.W.

1979-01-01

The processes leading to negative ion production in a hydrogen plasma are reviewed. Dissociative attachment of electrons to highly excited vibrational states of hydrogen molecules appears to be the most probable source of negative ions. The possibility of significant negative ion production via dissociative recombination of H 3 + with electrons cannot be excluded. The survival probability of vibrationally excited hydrogen molecules in wall collisions may be a critical parameter in interpreting the data

Non-noble metal graphene oxide-copper (II) ions hybrid electrodes for electrocatalytic hydrogen evolution reaction

KAUST Repository

Muralikrishna, S.

2015-08-25

Non-noble metal and inexpensive graphene oxide-copper (II) ions (GO-Cu2+) hybrid catalysts have been explored for the hydrogen evolution reaction (HER). We were able to tune the binding abilities of GO toward the Cu2+ ions and hence their catalytic properties by altering the pH. We have utilized the oxygen functional moieties such as carboxylate, epoxide, and hydroxyl groups on the edge and basal planes of the GO for binding the Cu2+ ions through dative bonds. The GO-Cu2+ hybrid materials were characterized by cyclic voltammetry in sodium acetate buffer solution. The morphology of the hybrid GO-Cu2+ was characterized by atomic force microscopy. The GO-Cu2+ hybrid electrodes show good electrocatalytic activity for HER with low overpotential in acidic solution. The Tafel slope for the GO-Cu2+ hybrid electrode implies that the primary discharge step is the rate determining step and HER proceed with Volmer step. © 2015 American Institute of Chemical Engineers Environ Prog.

Universal FFM Hydrogen Spectral Line Shapes Applied to Ions and Electrons

Science.gov (United States)

Mossé, C.; Calisti, A.; Ferri, S.; Talin, B.; Bureyeva, L. A.; Lisitsa, V. S.

2008-10-01

We present a method for the calculation of hydrogen spectral line shapes based on two combined approaches: Universal Model and FFM procedure. We start with the analytical functions for the intensities of the Stark components of radiative transitions between highly excited atomic states with large values of principal quantum numbers n,n'γ1, with Δn = n-n'≪n for the specific cases of Hn-α line (Δn = 1) and Hn-β line (Δn = 2). The FFM line shape is obtained by averaging on the electric field of the Hooper's field distribution for ion and electron perturber dynamics and by mixing the Stark components with a jumping frequency rate ve (vi) where v = N1/3u (N is electron density and u is the ion or electron thermal velocity). Finally, the total line shape is given by convolution of ion and electron line shapes. Hydrogen line shape calculations for Balmer Hα and Hβ lines are compared to experimental results in low density plasma (Ne˜1016-1017cm-3) and low electron temperature in order of 10 000K. This method relying on analytic expressions permits fast calculation of Hn-α and Hn-β lines of hydrogen and could be used in the study of the Stark broadening of radio recombination lines for high principal quantum number.

Hydrogen Bonding, (1)H NMR, and Molecular Electron Density Topographical Characteristics of Ionic Liquids Based on Amino Acid Cations and Their Ester Derivatives.

Science.gov (United States)

Rao, Soniya S; Bejoy, Namitha Brijit; Gejji, Shridhar P

2015-08-13

Amino acid ionic liquids (AAILs) have attracted significant attention in the recent literature owing to their ubiquitous applications in diversifying areas of modern chemistry, materials science, and biosciences. The present work focuses on unraveling the molecular interactions underlying AAILs. Electronic structures of ion pairs consisting of amino acid cations ([AA(+)], AA = Gly, Ala, Val, Leu, Ile, Pro, Ser, Thr) and their ester substituted derivatives [AAE(+)] interacting with nitrate anion [NO3(-)] have been obtained from the dispersion corrected M06-2x density functional theory. The formation of ion pair is accompanied by the transfer of proton from quaternary nitrogen to anion facilitated via hydrogen bonding. The [Ile], [Pro], [Ser], and [Thr] and their esters reveal relatively strong inter- as well as intramolecular hydrogen-bonding interactions. Consequently, the hierarchy in binding energies of [AA][NO3] ion pairs and their ester analogues turns out to be [Gly] > [Ala] > [Ser] ∼ [Val] ∼ [Ile] > [Leu] ∼ [Thr] > [Pro]. The work underlines how the interplay of intra- as well as intermolecular hydrogen-bonding interactions in [AA]- and [AAE]-based ILs manifest in their infrared and (1)H NMR spectra. Substitution of -OCH3 functional group in [AA][NO3] ILs lowers the melting point attributed to weaker hydrogen-bonding interactions, making them suitable for room temperature applications. As opposed to gas phase structures, the presence of solvent (DMSO) does not bring about any proton transfer in the ion pairs or their ester analogues. Calculated (1)H NMR chemical shifts of the solvated structures agree well with those from experiment. Correlations of decomposition temperatures in [AA]- and [AAE]-based ILs with binding energies and electron densities at the bond critical point(s) in molecular electron density topography, have been established.

Low energy cross section data for ion-molecule reactions in hydrogen systems and for charge transfer of multiply charged ions with atoms and molecules

International Nuclear Information System (INIS)

Okuno, Kazuhiko

2007-04-01

Systematic cross section measurements for ion-molecule reactions in hydrogen systems and for charge transfer of multiply charged ions in low energy collisions with atoms and molecules have been performed continuously by the identical apparatus installed with an octo-pole ion beam guide (OPIG) since 1980 till 2004. Recently, all of accumulated cross section data for a hundred collision systems has been entered into CMOL and CHART of the NIFS atomic and molecular numerical database together with some related cross section data. In this present paper, complicated ion-molecule reactions in hydrogen systems are revealed and the brief outlines of specific properties in low energy charge transfer collisions of multiply charged ions with atoms and molecules are introduced. (author)

H- ion sources for CERN's Linac4

Science.gov (United States)

Lettry, J.; Aguglia, D.; Coutron, Y.; Chaudet, E.; Dallocchio, A.; Gil Flores, J.; Hansen, J.; Mahner, E.; Mathot, S.; Mattei, S.; Midttun, O.; Moyret, P.; Nisbet, D.; O'Neil, M.; Paoluzzi, M.; Pasquino, C.; Pereira, H.; Arias, J. Sanchez; Schmitzer, C.; Scrivens, R.; Steyaert, D.

2013-02-01

The specifications set to the Linac4 ion source are: H- ion pulses of 0.5 ms duration, 80 mA intensity and 45 keV energy within a normalized emittance of 0.25 mmmrad RMS at a repetition rate of 2 Hz. In 2010, during the commissioning of a prototype based on H- production from the plasma volume, it was observed that the powerful co-extracted electron beam inherent to this type of ion source could destroy its electron beam dump well before reaching nominal parameters. However, the same source was able to provide 80 mA of protons mixed with a small fraction of H2+ and H3+ molecular ions. The commissioning of the radio frequency quadrupole accelerator (RFQ), beam chopper and H- beam diagnostics of the Linac4 are scheduled for 2012 and its final installation in the underground building is to start in 2013. Therefore, a crash program was launched in 2010 and reviewed in 2011 aiming at keeping the original Linac4 schedule with the following deliverables: Design and production of a volume ion source prototype suitable for 20-30 mA H- and 80 mA proton pulses at 45 keV by mid-2012. This first prototype will be dedicated to the commissioning of the low energy components of the Linac4. Design and production of a second prototype suitable for 40-50 mA H- based on an external RF solenoid plasma heating and cesiated-surface production mechanism in 2013 and a third prototype based on BNL's Magnetron aiming at reliable 2 Hz and 80 mA H- operations in 2014. In order to ease the future maintenance and allow operation with Ion sources based on three different production principles, an ion source "front end" providing alignment features, pulsed gas injection, pumping units, beam tuning capabilities and pulsed bipolar high voltage acceleration was designed and is being produced. This paper describes the progress of the Linac4 ion source program, the design of the Front end and first ion source prototype. Preliminary results of the summer 2012 commissioning are presented. The outlook on

Electron-capture cross sections for low-energy highly charged neon and argon ions from molecular and atomic hydrogen

International Nuclear Information System (INIS)

Can, C.; Gray, T.J.; Varghese, S.L.; Hall, J.M.; Tunnell, L.N.

1985-01-01

Electron-capture cross sections for low-velocity (10 6 --10 7 cm/s) highly charged Ne/sup q/+ (2< or =q< or =7) and Ar/sup q/+ (2< or =q< or =10)= projectiles incident on molecular- and atomic-hydrogen targets have been measured. A recoil-ion source that used the collisions of fast heavy ions (1 MeV/amu) with target gas atoms was utilized to produce slow highly charged ions. Atomic hydrogen was produced by dissociating hydrogen molecules in a high-temperature oven. Measurements and analysis of the data for molecular- and atomic-hydrogen targets are discussed in detail. The measured absolute cross sections are compared with published data and predictions of theoretical models

New hydrogen titanium phosphate sulfate electrodes for Li-ion and Na-ion batteries

Science.gov (United States)

Zhao, Ran; Mieritz, Daniel; Seo, Dong-Kyun; Chan, Candace K.

2017-03-01

NASICON-type materials with general formula AxM2(PO4)3 (A = Li or Na, M = Ti, V, and Fe) are promising candidates for Li- and Na-ion batteries due to their open three-dimensional framework structure. Here we report the electrochemical properties of hydrogen titanium phosphate sulfate, H0.4Ti2(PO4)2.4(SO4)0.6 (HTPS), a new mixed polyanion material with NASICON structure. Micron-sized HTPS aggregates with crystallite grain size of ca. 23 nm are synthesized using a sol-gel synthesis in an acidic medium. The properties of the as-synthesized HTPS, ball-milled HTPS, and samples prepared as carbon composites using an in-situ glucose decomposition reaction are investigated. A capacity of 148 mAh g-1 corresponding to insertion of 2 Li+ per formula unit is observed in the ball-milled HTPS over the potential window of 1.5-3.4 V vs. Li/Li+. Lithiation at ca. 2.8 and 2.5 V is determined to occur through filling of the M1 and M2 sites, respectively. Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) are used characterize the HTPS before and after cycling. Evaluation of the HTPS in a Na-ion cell is also performed. A discharge capacity of 93 mAh g-1 with sodiation at ca. 2.9 and 2.2 V vs. Na/Na+ is observed.

The effect of TTNT nanotubes on hydrogen sorption using MgH2

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Mariana Coutinho Brum

2013-06-01

Full Text Available Nanotubes are promising materials to be used with magnesium hydride, as catalysts, in order to enhance hydrogen sorption. A study was performed on the hydrogen absorption/desorption properties of MgH2 with the addition of TTNT (TiTanate NanoTubes. The MgH2-TTNT composite was prepared by ball milling and the influence of the TTNT amount (1.0 and 5.0 wt. (% on the hydrogen capacity was evaluated. The milling of pure MgH2 was performed for 24 hours and afterwards the MgH2-TTNT composite was milled for 20 minutes. Transmission Electronic Microscopy (TEM and Scanning Electron Microscopy (SEM were used to evaluate the nanotube synthesis and show the particle morphology of the MgH2-TTNT composite, respectively. The Differential Scanning Calorimetry (DSC examination provided some evidence with the shifting of the peaks obtained when the amount of TTNT is increased. The hydrogen absorption/desorption kinetics tests showed that the TTNT nanotubes can enhance hydrogen sorption effectively and the total hydrogen capacity obtained was 6.5 wt. (%.

The effect of TTNT nanotubes on hydrogen sorption using MgH2

International Nuclear Information System (INIS)

Brum, Mariana Coutinho; Jardim, Paula Mendes; Conceicao, Monique Osorio Talarico da; Santos, Dilson Silva dos

2013-01-01

Nanotubes are promising materials to be used with magnesium hydride, as catalysts, in order to enhance hydrogen sorption. A study was performed on the hydrogen absorption/desorption properties of MgH 2 with the addition of TTNT (TiTanate nanotubes). The MgH 2 -TTNT composite was prepared by ball milling and the influence of the TTNT amount (1.0 and 5.0 wt. (%)) on the hydrogen capacity was evaluated. The milling of pure MgH 2 was performed for 24 hours and afterwards the MgH 2 -TTNT composite was milled for 20 minutes. Transmission Electronic Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to evaluate the nanotube synthesis and show the particle morphology of the MgH 2 -TTNT composite, respectively. The Differential Scanning Calorimetry (DSC) examination provided some evidence with the shifting of the peaks obtained when the amount of TTNT is increased. The hydrogen absorption/desorption kinetics tests showed that the TTNT nanotubes can enhance hydrogen sorption effectively and the total hydrogen capacity obtained was 6.5 wt. (%). (author)

Hydrogen ion-driven permeation in carbonaceous films

International Nuclear Information System (INIS)

Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

1989-01-01

This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C:H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D 3 + ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5x10 14 D/cm 2 s to 5x10 15 D/cm 2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C:H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C:H films. (orig.)

Hydrogen ion-driven permeation in carbonaceous films

Energy Technology Data Exchange (ETDEWEB)

Anderl, R.A.; Holland, D.F.; Longhurst, G.R.

1989-04-01

This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C:H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D/sub 3//sup +/ ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5x10/sup 14/ D/cm/sup 2/ s to 5x10/sup 15/ D/cm/sup 2/ s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C:H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C:H films. (orig.).

Hydrogen ion-driven permeation in carbonaceous films

Science.gov (United States)

Anderl, R. A.; Holland, D. F.; Longhurst, G. R.

1989-04-01

This paper presents the results of investigations into the permeation properties of amorphous carbonaceous, a-C: H, films produced by plasmachemical deposition techniques. Carbonaceous films on iron substrates with thickness ranging from 60 nm to 110 nm were subjected to high fluence implantations with mass analyzed D +3 ions with energies ranging from 600 eV to 3000 eV and fluxes ranging from 5 × 10 14D/ cm2 s to 5 × 10 15D/ cm2 s, respectively. Deuterium re-emission upstream, deuterium permeation downstream and secondary ions sputtered from the implantation surface were measured as a function of implantation fluence for specimens at 420 K. The present studies indicate that the a-C : H film permeability is directly related to the time, hence the fluence, required to achieve isotopic replacement and saturation of the deuterium ion beam atoms stopped in the implant region. Once the deuterium saturation level is achieved in the layer, a significant fraction of the implanting ions can result in permeation. For the present experiment, this permeation factor was much higher than that for uncoated iron specimens subjected to similar beam conditions. Carbon sputter yields of 0.008-0.01 C/D were determined in this work for 1000-eV to 400-eV deuterium ions incident on a-C : H films.

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

Energy Technology Data Exchange (ETDEWEB)

Onai, M., E-mail: onai@ppl.appi.keio.ac.jp; Fujita, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Etoh, H.; Aoki, Y. [Sumitomo Heavy Industries, Ltd., Tokyo 141-6025 (Japan); Shibata, T. [High Energy Accelerator Research Organization (KEK), Ibaraki (Japan); Mattei, S.; Lettry, J. [CERN Rte de Meyrin, 1200 Geneva (Switzerland)

2016-02-15

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

The 100th anniversary of pH (1909-2009. Negative logarithms for measuring hydrogen ions: are they essential in medicine? Part I

Directory of Open Access Journals (Sweden)

Francesco Sgambato

2013-03-01

Full Text Available Introduction: It has been 100 years since the concept of pH (1909-2009 was ‘‘invented’’ by the Danish chemist-mathematician Søren Peter Lauritz Sørensen (1868-1939 in the chemistry laboratories of the Carlsberg Brewery in Copenhagen. The anniversary provides an opportunity to examine the crucial importance in human life of acid-base balance. Materials and methods: The authors review the historical process that led to the creation of the pH scale, with citation of passages from the original work of Sørensen published 100 years ago. This is followed by a critical analysis of the debate regarding the use of logarithmstomeasure hydrogen ion concentrations based on data from scientific papers published over the past 50 years (1960-2010. Results and discussion: The authors conclude that the concept of acid-base balance can be approached and taught in a simpler, more exciting, and even pleasant fashion without using the infamous and abstruse Henderson-Hasselbalch equation. The whole rationale underlying the understanding and clinical application of this vital topic is clearly and unquestionably inherent simpler, more manageable formula introduced by Henderson (without logs, which is useful and quite adequate for use in medical education.

Effect of Hydrogen Peroxide Content on the Preparation of Peroxotitanate Materials for the Treatment of Radioactive Wastewater

Directory of Open Access Journals (Sweden)

Wein-Duo Yang

2016-01-01

Full Text Available The modification of peroxotitanate using hydrogen peroxide significantly improved the ion-exchange capacity of titanate materials as sorbents for metal ions contained in a radioactive waste simulant solution. The effects of hydrogen peroxide content (hydrogen peroxide/titanium isopropoxide molar ratios, hereafter expressed as H/T on the properties of as-prepared titanate synthesized at 130°C and at pH of 6-7, followed by freeze-drying, were investigated. The peroxotitanate materials thus obtained were characterized by XRD, BET, SEM, TEM, EDX, ICP, and Raman spectroscopy. At an H/T ratio of 2, peroxotitanate predominantly exhibited an amorphous structure, with a clearly observed tubular or fibrous structure. Furthermore, peroxotitanate modified at an H/T ratio of 2 exhibited the best ion-exchange capacity of 191 mg g−1 for metal ions contained in a radioactive waste simulant solution. Hence, these peroxotitanate materials are suitable for removing metal ions from wastewater, especially lanthanide ions (Ln3+ and Sr2+.

Atomic processes in hydrogen and deuterium negative ion discharges

International Nuclear Information System (INIS)

Hiskes, J.R.

1992-01-01

A knowledge of the atomic processes active in a hydrogen negative ion discharge and their respective rates is an essential component of the interpretation, modeling, and enhancement of negative ion systems. The generation of the cross sections and rate processes appropriate to this problem has been a principal activity at several laboratories. In this paper is discussed those collision processes that are of major importance for the destruction of the vibrationally excited molecules generated in the discharge, processes that are essential to the valuation of the optimization procedure that is to be discussed in this paper

Hydration effect on ion exchange resin irradiated by swift heavy ions and gamma rays

Science.gov (United States)

Boughattas, I.; Labed, V.; Gerenton, A.; Ngono-Ravache, Y.; Dannoux-Papin, A.

2018-06-01

Gamma radiolysis of ion exchange resins (IER) is widely studied since the sixties, as a function of different parameters (resin type, dose, atmosphere, water content …). However, to our knowledge, there are very few data concerning hydrogen emission from anionic and cationic resins irradiated at high Linear Energy Transfers (LET). In the present work, we focus on the influence of hydration on hydrogen emission, in anionic and cationic resins irradiated under inert atmosphere using Swift Heavy Ions (SHI) and gamma irradiations. The radiation chemical yield of molecular hydrogen is nonlinear with water content for both resins. The molecular hydrogen production depends first on the water form in IER (free or linked) and second on the solubility of degradation products. Three steps have been observed: at lower water content where G(H2) is stable, at 50%, G(H2) increases due to reactions between water radiolytic species and the resin functional groups and at high water content, G(H2) decreases probably due to its accumulation in water and its consumption by hydroxyl radicals in the supernatant.

Final Report: Metal Perhydrides for Hydrogen Storage

Energy Technology Data Exchange (ETDEWEB)

Hwang, J-Y.; Shi, S.; Hackney, S.; Swenson, D.; Hu, Y.

2011-07-26

Hydrogen is a promising energy source for the future economy due to its environmental friendliness. One of the important obstacles for the utilization of hydrogen as a fuel source for applications such as fuel cells is the storage of hydrogen. In the infrastructure of the expected hydrogen economy, hydrogen storage is one of the key enabling technologies. Although hydrogen possesses the highest gravimetric energy content (142 KJ/g) of all fuels, its volumetric energy density (8 MJ/L) is very low. It is desired to increase the volumetric energy density of hydrogen in a system to satisfy various applications. Research on hydrogen storage has been pursed for many years. Various storage technologies, including liquefaction, compression, metal hydride, chemical hydride, and adsorption, have been examined. Liquefaction and high pressure compression are not desired due to concerns related to complicated devices, high energy cost and safety. Metal hydrides and chemical hydrides have high gravimetric and volumetric energy densities but encounter issues because high temperature is required for the release of hydrogen, due to the strong bonding of hydrogen in the compounds. Reversibility of hydrogen loading and unloading is another concern. Adsorption of hydrogen on high surface area sorbents such as activated carbon and organic metal frameworks does not have the reversibility problem. But on the other hand, the weak force (primarily the van der Waals force) between hydrogen and the sorbent yields a very small amount of adsorption capacity at ambient temperature. Significant storage capacity can only be achieved at low temperatures such as 77K. The use of liquid nitrogen in a hydrogen storage system is not practical. Perhydrides are proposed as novel hydrogen storage materials that may overcome barriers slowing advances to a hydrogen fuel economy. In conventional hydrides, e.g. metal hydrides, the number of hydrogen atoms equals the total valence of the metal ions. One LiH

Effect of argon ion sputtering of surface on hydrogen permeation through vanadium

International Nuclear Information System (INIS)

Yamawaki, Michio; Namba, Takashi; Yoneoka, Toshiaki; Kanno, Masayoshi; Shida, Koji.

1983-01-01

In order to measure the hydrogen permeation rate through V with atomically cleaned surface, an Ar ion sputtering apparatus has been installed in the hydrogen permeability measuring system. The permeation rate of the initial specimen was found to be increased by about one order of magnitude after Ar ion sputtering of its upstream side surface. Repeating of such a sputter-cleaning was not so much effective in increasing the steady state permeation rate as the initial sputtering was, but it accelerated the transient response rate by a factor of 2 or 3. The transient response rate was also accelerated by the increase of hydrogen pressure, but this effect tended to be diminished by the sputter-cleaning of specimen surface. The surface impurity layer on the downstream side of specimen was also inferred to act as a diffusion barrier affecting the steady state permeation rate. The present value of activation energy for hydrogen permeation through V at temperatures below 873K was the smallest one ever obtained, showing that the surface effect was minimized in the present study on account of the surface sputter-cleaning in addition to the ultra high vacuum system. (author)

The populations of excited levels of hydrogen-like and helium-like ions in plasmas traversed by neutral hydrogen beams

International Nuclear Information System (INIS)

Spence, J.; Summers, H.P.

1985-01-01

This paper examines the populations of levels of impurity ions in a spartially homogeneous plasma containing primarily thermal electrons and protons and monoenergetic neutral hydrogen atoms. Of special concern is the role of recombination which may include the radiative, three-body and dielectronic process together with charge exchange capture from neutral hydrogen beams. The influence of these primary processes on the population is modified by radiative transitions and redistributive transitions due to collisions with electrons and protons in the plasma. The behaviour of the populations of the ions C 5+ , C 4+ and Ar 16+ with variation of plasma parameters is explored in the present work. A bundled principal quantum level picture and a more elaborate LS resolved picture are used which allow investigation of the expected spectral emission and its sensitivity to uncertainty in the primary rates. The variation of the impurity ion spectrum in transiently recombining or ionising conditions is also considered. (orig.)

Desalination and hydrogen, chlorine, and sodium hydroxide production via electrophoretic ion exchange and precipitation.

Science.gov (United States)

Shkolnikov, Viktor; Bahga, Supreet S; Santiago, Juan G

2012-08-28

We demonstrate and analyze a novel desalination method which works by electrophoretically replacing sodium and chloride in feed salt water with a pair of ions, calcium and carbonate, that react and precipitate out. The resulting calcium carbonate precipitate is benign to health, and can be filtered or settled out, yielding low ionic strength product water. The ion exchange and precipitation employs self-sharpening interfaces induced by movement of multiple ions in an electric field to prevent contamination of the product water. Simultaneously, the electrolysis associated with the electromigration produces hydrogen gas, chlorine gas, and sodium hydroxide. We conducted an experimental study of this method's basic efficacy to desalinate salt water from 100 to 600 mol m(-3) sodium chloride. We also present physicochemical models of the process, and analyze replacement reagents consumption, permeate recovery ratio, and energy consumption. We hypothesize that the precipitate can be recycled back to replacement reagents using the well-known, commercially implemented Solvay process. We show that the method's permeate recovery ratio is 58% to 46%, which is on par with that of reverse osmosis. We show that the method's energy consumption requirement over and above that necessary to generate electrolysis is 3 to 10 W h l(-1), which is on par with the energy consumed by state-of-the-art desalination methods. Furthermore, the method operates at ambient temperature and pressure, and uses no specialized membranes. The process may be feasible as a part of a desalination-co-generation facility: generating fresh water, hydrogen and chlorine gas, and sodium hydroxide.

Hydrogenation of graphene nanoflakes and C-H bond dissociation of hydrogenated graphene nanoflakes: a density functional theory study

Institute of Scientific and Technical Information of China (English)

Sheng Tao; Hui-Ting Liu; Liu-Ming Yan; Bao-Hua Yue; Ai-Jun Li

2017-01-01

The Gibbs free energy change for the hydrogenation of graphene nanoflakes Cn (n =24,28,30 and 32) and the C-H bond dissociation energy of hydrogenated graphene nanoflakes CnHm (n =24,28,30 and 32;and m =1,2 and 3) are evaluated using density functional theory calculations.It is concluded that the graphene nanoflakes and hydrogenated graphene nanoflakes accept the ortharyne structure with peripheral carbon atoms bonded via the most triple bonds and leaving the least unpaired dangling electrons.Five-membered rings are formed at the deep bay sites attributing to the stabilization effect from the pairing of dangling electrons.The hydrogenation reactions which eliminate one unpaired dangling electron and thus decrease the overall multiplicity of the graphene nanoflakes or hydrogenated graphene nanoflakes are spontaneous with negative or near zero Gibbs free energy change.And the resulting C-H bonds are stable with bond dissociation energy in the same range as those of aromatic compounds.The other C-H bonds are not as stable attributing to the excessive unpaired dangling electrons being filled into the C-H anti-bond orbital.

Scaling relations in elastic scattering cross sections between multiply charged ions and hydrogen

International Nuclear Information System (INIS)

Rodriguez, V.D.

1991-01-01

Differential elastic scattering cross sections of bare ions from hydrogen are calculated using the eikonal approximation. The results satisfy a scaling relation involving the scattering angle, the ion charge and a factor related to the ion mass. A semiclassical explanation in terms of a distant collision hypothesis for small scattering angle is proposed. A unified picture of related scaling rules found in direct processes is discussed. (author)

Scattering of Femtosecond Laser Pulses on the Negative Hydrogen Ion

Science.gov (United States)

Astapenko, V. A.; Moroz, N. N.

2018-05-01

Elastic scattering of ultrashort laser pulses (USLPs) on the negative hydrogen ion is considered. Results of calculations of the USLP scattering probability are presented and analyzed for pulses of two types: the corrected Gaussian pulse and wavelet pulse without carrier frequency depending on the problem parameters.

Dynamics of the reaction of the N+ ion with hydrogen isotopes and helium

International Nuclear Information System (INIS)

Ruska, W.E.W.

1976-01-01

Molecular beam techniques were used to study the reactive and non-reactive scattering of the nitrogen positive ion from hydrogen isotopes and helium, at energies above the stability limit for spectator stripping. Reactive scattering was observed from H 2 and HD targets. Non-reactive scattering was observed from H 2 and D 2 targets, and from He at one energy. A correlation diagram for the system is presented and compared with the available a priori calculations. Two surfaces are expected to lead to reaction. One is a 3 A 2 - 3 PI surface, the other, a 3 B 1 - 3 Σ - surface. Collinear approaches are expected to be most reactive on the 3 B 1 - 3 Σ - surface; noncollinear, on the 3 A 1 - 3 PI surface. Theoretical models are presented in which an incident hard sphere A, representing the projectile ion, strikes one of a pair of hard spheres B-C representing the B hydrogen molecule. After an impulsive A-B collision, an impulsive B-C collision may take place. The relative energy of A to B is then examined, and a reactive event is considered to have occurred if the energy is less than the dissociation energy for the A-B molecule. This model is treated both in the collinear case and in three dimensions. A graphical technique for the collinear case is summarized and applied to reaction on the 3 B 1 - 3 Σ - surface. An integral equation for the three-dimensional case is developed. A synthesis of two treatments, representing the behavior of the system on both reactive surfaces, and considering the charge-exchange channel, correctly predicts the observed product distribution. Predictions are also presented for the as yet unobserved case of reactive scattering from a D 2 target

Development of an intense negative hydrogen ion source with a wide-range of external magnetic filter field

International Nuclear Information System (INIS)

Takeiri, Y.; Ando, A.; Kaneko, O.

1994-09-01

An intense negative hydrogen ion source has been developed, which has a strong external magnetic filter field in the wide area of 35 cm x 62 cm produced by a pair of permanent magnet rows located with 35.4 cm separation. The filter strength is 70 G in the center and the line-integrated filter strength is 850 G cm, which keeps the low electron temperature in the extraction region. Strong cusp magnetic field, 1.8 kG on the chamber surface, is generated for improvement of the plasma confinement. These resulted in the high arc efficiency at the low operational gas pressure. A 16.2 A of the H - ion current with the energy of 47 keV was obtained at the arc efficiency of 0.1 A/kW at the gas pressure of 3.8 mTorr in the cesium-mode operation. The magnetic field in the extraction gap is also strong, 450 G, for the electron suppression. The ratio of the extraction to the negative ion currents was less than 2.2 at the gas pressure of 3 mTorr. The two-stage acceleration was tried, and a 13.6 A of the H - ion beam was accelerated to 125 keV. (author)

Study of the ionization of H{sup +}{sub 2} ions in strong laser fields; Untersuchung der Ionisation von H{sup +}{sub 2}-Ionen in starken Laserfeldern

Energy Technology Data Exchange (ETDEWEB)

Odenweller, Matthias

2010-07-01

In the framework of this thesis it has been succeeded to develop a worldwide unique measurement apparatur, by which hydrogen-molecule ions can be ionized by means of short laser pulses and the reaction product kinematically completely measured. For this a detection method following the Coltrims technique, in which both protons and electrons can be detected over the complete spatial angle. The H{sup +}{sub 2} ions origin from a high-frequency ion source and are accelerated to 400 keV. This ion beam is overlapped with a 780-nm laser pulse othe pulse length 40 fs. After the reaction the molecule ions fragments either via the dissociation channel H{sup +}{sub 2}+nh{nu}{yields}H+H{sup +} or via an ionization followed by a Coulomb explosion: H{sup +}{sub 2}+nh{nu}{yields}H{sup +}+H{sup +}+e{sup -}. The projectiles are detected after a drift path of about 3 m on an ion detector. For the detection of the electrons a special spectrometer was concipated. In the reaction it comes by the comparatively long pulse length already at low intensities to dissociation processes. The dissociating molecule reaches still during the increasing side of the laser pulse in this way distances, in which the charge-resonance-enhanced-ionization (CREI) can take place. Also the angular distribution of the measured protons lying in a very small angular range around the polarization direction of the laser suggests that CREI is the dominant ionization process. At circular polarization however a netto-acceleration of the electrons perpendicularly to the direction of the electric field at the ionization time takes place, so that the measurement of the electron momenta represents a suited measurement quantity for the study of the ionization process. By this way angular distributions of the electrons relatively to the internuclear axis within the polarization plane could be measured.

Installation of spectrally selective imaging system in RF negative ion source

International Nuclear Information System (INIS)

Ikeda, K.; Kisaki, M.; Nagaoka, K.; Nakano, H.; Osakabe, M.; Tsumori, K.; Kaneko, O.; Takeiri, Y.; Wünderlich, D.; Fantz, U.; Heinemann, B.; Geng, S.

2016-01-01

A spectrally selective imaging system has been installed in the RF negative ion source in the International Thermonuclear Experimental Reactor-relevant negative ion beam test facility ELISE (Extraction from a Large Ion Source Experiment) to investigate distribution of hydrogen Balmer-α emission (H α ) close to the production surface of hydrogen negative ion. We selected a GigE vision camera coupled with an optical band-path filter, which can be controlled remotely using high speed network connection. A distribution of H α emission near the bias plate has been clearly observed. The same time trend on H α intensities measured by the imaging diagnostic and the optical emission spectroscopy is confirmed

A procedure for reducing the concentration of hydrogen ions in acid anionic eluate and equipment therefore

International Nuclear Information System (INIS)

Parobek, P.; Baloun, S.; Plevac, S.

1989-01-01

The method is described of reducing the concentration of hydrogen ions in acid anionic eluate produced in the separation of uranium or other metals, in which anion exchanger elution, precipitation, filtration and precipitate and anion exchanger washing are used. The technological line for such elution comprises at least one ion exchange column and at least one container. They together form the first and the second stages of preparation of the acid anion elution solution, the sorption-elution separation of hydrogen ions on an cation exchanger being inserted between them. The preparation of the solution is divide into two stages. In the first stage, the acid and part of the solution for the preparation of the acid anion elution solution are supplied. The resulting enriched acid elution solution is fe onto the cation exchanger where the hydrogen ion concentration i reduced. It is then carried into the second stage where it is mixed with the remaining part of the solution. (B.S.)

Dissociative recombination of molecular ions H2+

International Nuclear Information System (INIS)

Abarenov, A.V.; Marchenko, V.S.

1989-01-01

The total cross sections of dissociation and dissociative recombination of slow electrons and molecular ions H 2 + have been calculated in terms of the quasiclassical and dipole approximations. In the calculations allowance was made for the quantum nature of vibrational motion of heavy particles and presence of autoionization of divergence states of the H 2 (Σ u , nl) molecules. It is shown that the H 2 + ion dissociation cross sections are dominant in increase of the electron energy in the ε >or approx. 2-3 eV region for H 2 + (v) ion distribution over the vibrational levels characteristic for the beam experiments. 15 refs.; 5 figs

Detection of hydrogen dissolved in acrylonitrile butadiene rubber by 1H nuclear magnetic resonance

Science.gov (United States)

Nishimura, Shin; Fujiwara, Hirotada

2012-01-01

Rubber materials, which are used for hydrogen gas seal, can dissolve hydrogen during exposure in high-pressure hydrogen gas. Dissolved hydrogen molecules were detected by solid state 1H NMR of the unfilled vulcanized acrylonitrile butadiene rubber. Two signals were observed at 4.5 ppm and 4.8 ppm, which were assignable to dissolved hydrogen, in the 1H NMR spectrum of NBR after being exposed 100 MPa hydrogen gas for 24 h at room temperature. These signals were shifted from that of gaseous hydrogen molecules. Assignment of the signals was confirmed by quantitative estimation of dissolved hydrogen and peak area of the signals.

Ion-acoustic waves and drift waves in negative ion sources

International Nuclear Information System (INIS)

Gerwin, R.A.

1989-01-01

Attention is directed towards instabilities induced in hydrogen plasmas due to the presence of the desired H/sup /minus// ions. Preliminary investigations indicate that when the electron temperature exceeds the temperature of the background ions (H + ), the H/sup /minus// beam causes collective instabilities even at very low (even vanishing) beam velocities, provided that the non-ideal properties of the background plasma are taken into consideration. The most dangerous instabilities involve oscillations transverse to the direction of beam extraction, and may thereby degrade the beam emittance. 5 refs

Hydrogen Learning for Local Leaders – H2L3

Energy Technology Data Exchange (ETDEWEB)

Serfass, Patrick [Technology Transition Corporation, Washington, DC (United States)

2017-03-30

The Hydrogen Learning for Local Leaders program, H2L3, elevates the knowledge about hydrogen by local government officials across the United States. The program reaches local leaders directly through “Hydrogen 101” workshops and webinar sessions; the creation and dissemination of a unique report on the hydrogen and fuel cell market in the US, covering 57 different sectors; and support of the Hydrogen Student Design Contest, a competition for interdisciplinary teams of university students to design hydrogen and fuel cell systems based on technology that’s currently commercially available.

Chemistry of radio-frequency source of negative hydrogen ions; Chemia radio-frekvencneho zdroja negativnych ionov vodika

Energy Technology Data Exchange (ETDEWEB)

Skoviera, J.; Cernusak, I. [Univerzita Komenskeho, Prirodovedecka fakulta, Katedra fyzikalnej a teoretickej chemie, 84215 Bratislava (Slovakia)

2013-04-16

International Thermonuclear Experimental Reactor (ITER) is a prototype of nuclear fusion reactor Tokamak currently build in Cadarache. It will use as one of primary plasma heating components a radiofrequency driven negative ion source of deuterium. The purpose of cesium evaporated in the part of this ion source is to react with free electrons which can incidentally destroy generated hydrogen ions and are co-extracted with the hydrogen beam. Goal of this work is to investigate majority of processes which might have impact on hydrogen anion in either formative or destructive way associated with cesium. Generally the caesium dynamics is very complex in such sources and the interplay of the individual contributions and their control to establish optimum caesium coverage of the plasma grid is still an open issue. (authors)

4-Methoxybenzamidinium hydrogen oxalate monohydrate

Directory of Open Access Journals (Sweden)

Simona Irrera

2012-12-01

Full Text Available The title hydrated salt, C8H11N2O+·C2HO4−·H2O, was synthesized by a reaction of 4-methoxybenzamidine (4-amidinoanisole and oxalic acid in water solution. In the cation, the amidinium group forms a dihedral angle of 15.60 (6° with the mean plane of the benzene ring. In the crystal, each amidinium unit is bound to three acetate anions and one water molecule by six distinct N—H...O hydrogen bonds. The ion pairs of the asymmetric unit are joined by two N—H...O hydrogen bonds into ionic dimers in which the carbonyl O atom of the semi-oxalate anion acts as a bifurcated acceptor, thus generating an R12(6 motif. These subunits are then joined through the remaining N—H...O hydrogen bonds to adjacent semi-oxalate anions into linear tetrameric chains running approximately along the b axis. The structure is stabilized by N—H...O and O—H...O intermolecular hydrogen bonds. The water molecule plays an important role in the cohesion and the stability of the crystal structure being involved in three hydrogen bonds connecting two semi-oxalate anions as donor and a benzamidinium cation as acceptor.

Revisiting the Hydrogen Storage Behavior of the Na-O-H System

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Jianfeng Mao

2015-04-01

Full Text Available Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS experiments of NaH-NaOH composites reveal two principal features: Firstly, an H2 desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH and hydridic hydrogen (in NaH important in the dehydrogenation mechanism, but that also an intra-phase Hδ+… Hδ– interaction may be a crucial step in the desorption process.

CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

Science.gov (United States)

Rupprechter, G.; Kaichev, V. V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V. I.

2004-07-01

The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H 2 mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH xO species as precursors for CO bond cleavage and that the formation of CH xO is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

Energy Technology Data Exchange (ETDEWEB)

Rupprechter, G.; Kaichev, V.V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V.I

2004-07-31

The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H{sub 2} mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH{sub x}O species as precursors for C---O bond cleavage and that the formation of CH{sub x}O is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

On problems of hydrogen load of sponge palladium and determination of hydrogen content in it

International Nuclear Information System (INIS)

Mittag, E.; Pleis, U.; Roemer, J.

1977-01-01

In the process of catalytic dehalogenation applied as a method for preparation of organic compounds labelled with tritium a special importance pertains to the determination of hydrogen (or tritium) bound on the catalyst. Hydrogen contained in palladium black may be determined quantitatively by oxidation with Pd ++ ions and successive potentiometric titration of the released H + ions. The method permits to obtain data on the quality of the catalyst and on the gas losses on the catalyst. Moreover, in connection with the radioactivity measurement, this method may be used for specific activity determination of the tritium gas

Enhancing optical gains in Si nanocrystals via hydrogenation and cerium ion doping

International Nuclear Information System (INIS)

Wang, Dong-Chen; Li, Yan-Li; Song, Sheng-Chi; Guo, Wen-Ping; Lu, Ming; Chen, Jia-Rong

2014-01-01

We report optical gain enhancements in Si nanocrystals (Si-NCs) via hydrogenation and Ce 3+ ion doping. Variable stripe length technique was used to obtain gains. At 0.3 W/cm 2 pumping power density of pulsed laser, net gains were observed together with gain enhancements after hydrogenation and/or Ce 3+ ion doping; gains after loss corrections were between 89.52 and 341.95 cm −1 ; and the photoluminescence (PL) lifetime was found to decrease with the increasing gain enhancement. At 0.04 W/cm 2 power density, however, no net gain was found and the PL lifetime increased with the increasing PL enhancement. The results were discussed according to stimulated and spontaneous excitation and de-excitation mechanisms of Si-NCs.

Uptake of hydrogen from some carbon fibres examined by Secondary Ion Mass Spectrometry

International Nuclear Information System (INIS)

Madronero, A.; Aguado, J.; Blanco, J.M.; Lopez, A.

2011-01-01

The use of carbonaceous materials for hydrogen storage is not as simple as it may seem. Hydrogen atoms have different bonding energies and are incorporated into different types of these materials. Therefore, it is particularly important to distinguish between the surfacial atoms and those that are embedded in the bulk of the sample. SIMS spectrograph with periodical interruptions of the ion beam enables us to appreciate that at room temperature and in high vacuum, some outgassing of the surfacial hydrogen takes place.

Charge transfer between hydrogen(deuterium) ions and atoms in metal vapors

International Nuclear Information System (INIS)

Alvarez T, I.; Cisneros G, C.

1981-01-01

The current state of the experiments on charge transfer between hydrogen (deuterium) ions and atoms in metal vapors are given. Emphasis is given to describing different experimental techniques. The results of calculations if available, are compared with existing experimental data. (author)

Some developments in polarized ion sources

International Nuclear Information System (INIS)

Witteveen, G.J.

1979-01-01

Investigations concerning an atomic beam source are presented and a new polarized ion source of a more universal type is introduced. Polarized and unpolarized beams of positively or negatively charged ions can be produced with this new version and the theoretical limits are a polarized negative hydrogen ion beam with an intensity of about 1 mH and a polarized proton beam with an intensity of 10 mH. (C.F.)

Optically pumped polarized H- ion source

International Nuclear Information System (INIS)

Anderson, L.W.

1986-01-01

The current status and future prospects for the optically pumped polarized H - ion source are discussed. At the present time H - ion currents of 60 μA and with a polarization of 65% have been produced. The ion current and polarization can be increased significantly if the optically pumped Na charge exchange target density and polarization can be increased. Studies of wall surfaces that permit many bounces before depolarizing the Na electron spin and studies of radiation trapping in optically pumped Na indicate that the Na target density and polarization can be increased substantially. 27 refs., 6 figs., 2 tabs